Discussion Thread – Japanese nuclear reactors and the 11 March 2011 earthquake

Please use this Discussion Thread for the situation in Japan with respect to the Miyagiken-Oki earthquake (9.0 magnitude) and associated 10m tsunami, and its impact on the local nuclear reactors. Here is a précis of the situation as I understand it:

1. There is no credible risk of a serious accident. All reactors responded by insertion of control rods to shut down their nuclear reactions. Thus, power levels in all cases dropped quickly to about 5% of maximum output,  and the nuclear chain reaction ceased (i.e., all units are subcritical).

Note: I judge the situation would currently be rated INES Level 4: Accident with local consequences on the international nuclear event scale. Update: This level has been confirmed by WNN (5:50 GMT).

2. The concern is providing emergency cooling water to the reactor cores to remove decay heat from the fuel rods. This residual heat comes from the fission products, and will be persistent, but diminishes rapidly over time (i.e., most decay heat occurs over minutes and hours, with cold shutdown within a few days).

3. At one plant, the 40-year old Fukushima Daiichi (unit #1 opened in 1971), the backup diesel generators supply power to the core cooling system failed (apparently due to damage from the tsunami). This allowed pressure to build up in at least one of the reactors cores to about 50% higher than normal (unit 1), and requires venting of very mildly radioactive steam (contains trace levels of tritium). Some discussion here.

4. The nuclear reactor containments were undamaged by the tsunami or earthquake — these structures are sealed from flooding damage and are seismically isolated.

5. New generators and batteries have been transported to the Daiichi site in to provide power to the pumps. The emergency core cooling systems (ECCS) have been invoked, which follows the principle of defense in depth (however, see point #8, below, and TEPCO updates).

6. There are reports of partial exposure of the fuel at Daiichi unit #1, following coolant evaporation that, for a short time, exceeded inputs from the secondary cooling system. Such exposure can lead to some melting of the metal cladding (the ‘wrapping’ of the fuel rods), or the uranium rods themselves if the exposure is prolonged. This is what is technically referred to as a ‘meltdown’. I am still not clear if this exposure of the fuel assemblies actually happened (some evidence here), nor if any fuel underwent melt (due to decay heat, not a critical nuclear reaction).

7. The plant closest to the earthquake epicentre, Onagawa, stood up remarkably well, although there was a fire in a turbine building on site but not associated with the reactor operations, and therefore was not involved with any radioactive systems.

8. There has been an explosion at Fukushima Daiichi at 16:30 JST (7:30 GMT) on March 12. Note: There is no critical nuclear reaction occurring in any of these reactors, and it CANNOT reinitiate as all neutron-absorbing control rods are grounded. As such, any at a plant site fire would be chemical (e.g., hydrogen) or steam pressure during venting (see point #3).

Quote from WNN on the explosion:

Television cameras trained on the plant captured a dramatic explosion surrounding Fukushima Daiichi 1 at around 6pm. Amid a visible pressure release and a cloud of dust it was not possible to immediately know the extent of any damage. Later television shots showed a naked steel frame remaining at the top of the reactor building. The external building structure does not act as the containment, which is an airtight engineered boundary within.

Chief cabinet secretary Yukio Edano appeared on television to clarify that the explosion had damaged the walls and roof of the reactor building but had not compromised the containment.

Monitoring of Fukushima Daiichi 1 had previously shown an increase in radiation levels detected near to the unit emerging via routes such as the exhaust stack and the discharge canal. These included caesium-137 and iodine-131, Nisa said, noting that levels began to decrease after some time.

Nevertheless the amount of radiation detected at the site boundary reached 500 microSieverts per hour – exceeding a regulatory limit and triggering another set of emergency precautions. It also meant the incident has been rated at Level 4 on the International Nuclear Event Scale (INES) – an ‘accident with local consequences’.

Note: The seawater might be used for spraying within the containment, for additional cooling, rather than injection into the reactor core. That is what comes of too much uncertainty and too little hard information.

Japan Chief Cabinet Secretary Yukio Edano, via Reuters:

We’ve confirmed that the reactor container was not damaged. The explosion didn’t occur inside the reactor container. As such there was no large amount of radiation leakage outside…

Edano said due to the falling level of cooling water, hydrogen was generated and that leaked to the space between the building and the container and the explosion happened when the hydrogen mixed with oxygen there.

(I will edit the above section and provide further updates below, as more information comes to hand)

Some useful links for further information:

Battle to stabilise earthquake reactors (World Nuclear News)

Factbox – Experts comment on explosion at Japan nuclear plant (some excellent and informative quotes)

ANS Nuclear Cafe updates (useful news feed)

How to Cool a Nuclear Reactor (Scientific American interview with Scott Burnell from the NRC)

Nuclear Power Plants and Earthquakes (World Nuclear Association fact sheet)

Tokyo Electric Power Company updates here and here (the plant operators)

Capacity Factor: Some links on the Fukushima Daiichi #1 crisis (with updates)

This is a critical time for science, engineering and facts to trump hype, fear, uncertainty and doubt.

——————————

Updates Below
International Atomic Energy Agency: Japan nuclear plants nearest earthquake safely shut down

TEPCO updates for Fukushima Daiichi (Plant #1) and Daini (Plant #2): 8 am, 13 March

[Nuclear Power Station]
Fukushima Daiichi Nuclear Power Station:

Units 1 to 3: shutdown due to earthquake

Units 4 to 6: outage due to regular inspection

* The national government has instructed evacuation for those local residents within 20km radius of the site periphery.

* The value of radioactive material (iodine, etc) is increasing according to the monitoring car at the site (outside of the site). One of the monitoring posts is also indicating higher than normal level.

* Since the amount of radiation at the boundary of the site exceeds the limits, we decide at 4:17PM, Mar 12 and we have reported and/or noticed the government agencies concerned to apply the clause 1 of the Article 15 of the Radiation Disaster Measure at 5PM, Mar 12.

* In addition, a vertical earthquake hit the site and big explosion has happened near the Unit 1 and smoke breaks out around 3:36PM, Mar 12th.

* We started injection of sea water into the reactor core of Unit 1 at 8:20PM, Mar 12 and then boric acid subsequently.

* High Pressure Coolant Injection System of Unit 3 automatically stopped. We endeavored to restart the Reactor Core Isolation Cooling System but failed. Also, we could not confirm the water inflow of Emergency Core Cooling System. As such, we decided at 5.10AM, Mar 12, and we reported and/or noticed the government agencies concerned to apply the clause 1 of the Article 15 of the Radiation Disaster Measure at 5:58AM, Mar 13.

In order to fully secure safety, we operated the vent valve to reduce the pressure of the reactor containment vessels (partial release of air containing radioactive materials) and completed the procedure at 8:41AM, Mar 13,

* We continue endeavoring to secure the safety that all we can do and monitoring the periphery.

Fukushima Daini Nuclear Power Station:

Units 1 to 4: shutdown due to earthquake

* The national government has instructed evacuation for those local residents within 10km radius of the periphery.

* At present, we have decided to prepare implementing measures to reduce the pressure of the reactor containment vessel (partial discharge of air containing radioactive materials) in order to fully secure safety. These measures are considered to be implemented in Units 1, 2 and 3 and accordingly, we have reported and/or noticed the government agencies concerned.

* Unit 3 has been stopped and being “nuclear reactor cooling hot stop” at 12:15PM.

* The operator trapped in the crane operating console of the exhaust stack was transferred to the ground at 5:13PM and confirmed the death at 5:17PM.

Kashiwazaki Kariwa Nuclear Power Station:
Units 1, 5, 6, 7: normal operation

Units 2 to 4: outage due to regular inspection

From Margaret Harding:

Heat from the nuclear fuel rods must be removed by water in a cooling system, but that requires power to run the pumps, align the valves in the pipes and run the instruments. The plant requires a continuous supply of electricity even after the reactor stops generating power.

With the steam-driven pump in operation, pressure valves on the reactor vessel would open automatically as pressure rose too high, or could be opened by operators. “It’s not like they have a breach; there’s no broken pipe venting steam,” said Margaret E. Harding, a nuclear safety consultant who managed a team at General Electric, the reactors’ designer, that analyzed pressure buildup in reactor containments.

You’re getting pops of release valves for minutes, not hours, that take pressure back down”

IAEA alert log:

Japanese authorities have informed the IAEA’s Incident and Emergency Centre (IEC) that today’s earthquake and tsunami have cut the supply of off-site power to the Fukushima Daiichi nuclear power plant. In addition, diesel generators intended to provide back-up electricity to the plant’s cooling system were disabled by tsunami flooding, and efforts to restore the diesel generators are continuing.

At Fukushima Daiichi, officials have declared a nuclear emergency situation, and at the nearby Fukushima Daini nuclear power plant, officials have declared a heightened alert condition.

Japanese authorities say there has so far been no release of radiation from any of the nuclear power plants affected by today’s earthquake and aftershocks.

Tsunamis and nuclear power plants:

Large undersea earthquakes often cause tsunamis – pressure waves which travel very rapidly across oceans and become massive waves over ten metres high when they reach shallow water, then washing well inland. The December 2004 tsunamis following a magnitude 9 earthquake in Indonesia reached the west coast of India and affected the Kalpakkam nuclear power plant near Madras/Chennai. When very abnormal water levels were detected in the cooling water intake, the plant shut down automatically. It was restarted six days later.

Even for a nuclear plant situated very close to sea level, the robust sealed containment structure around the reactor itself would prevent any damage to the nuclear part from a tsunami, though other parts of the plant might be damaged. No radiological hazard would be likely.

World Nuclear News updates (updated 11:44 pm GMT):

Attention is focused on the Fukushima Daiichi and Daini nuclear power plants as Japan struggles to cope in the aftermath of its worst earthquake in recorded history. An explosion on site did not damage containment. Sea water injection continues after a tsunami warning.

Three of Fukushima Daiichi’s six reactors were in operation when yesterday’s quake hit, at which point they shut down automatically and commenced removal of residual heat with the help of emergency diesel generators. These suddenly stopped about an hour later, and this has been put down to tsunami flooding by the International Atomic Energy Agency (IAEA).

The loss of the diesels led the plant owners Tokyo Electric Power Company (Tepco) to immediately notify the government of a technical emergency situation, which allows officials to take additional precautionary measures.

For many hours the primary focus of work at the site was to connect enough portable power modules to fully replace the diesels and enable the full operation of cooling systems.

Pressure and releases

Without enough power for cooling systems, decay heat from the reactor cores of units 1, 2 and 3 has gradually reduced coolant water levels through evaporation. The consequent increase in pressure in the coolant circuit can be managed via pressure release valves. However, this leads to an increase in pressure within the reactor building containment. Tepco has said that the pressure within the containment of Fukushima Daiichi 1 has reached around 840 kPa, compared to reference levels of 400 kPa.

The company has decided to manage this “for those units that cannot confirm certain levels of water injection” by means of a controlled release of air and water vapour to the atmosphere. Because this water has been through the reactor core, this would inevitably mean a certain release of radiation. The IAEA said this would be filtered to retain radiation within the containment. Tepco has confirmed it was in the process of relieving pressure at unit 1 while preparing to do the same for units 2 and 3.

Explosion

Television cameras trained on the plant captured a dramatic explosion surrounding unit 1 at around 6pm. Amid a visible pressure release and a cloud of dust it was not possible to immediately know the extent of any damage. Later television shots showed a naked steel frame remaining at the top of the reactor building. The external building structure does not act as the containment, which is an airtight engineered boundary within.

Chief cabinet secretary Yukio Edano appeared on television to clarify that the explosion had damaged the walls and roof of the reactor building but had not compromised the containment.

Monitoring of Fukushima Daiichi 1 had previously shown an increase in radiation levels detected emerging from the plant via routes such as the exhaust stack and the discharge canal. Tepco have said that the amount of radioactive material such as iodine it is detecting have been increasing. The amount of radiation at the site boundary now exceeds a regulatory limit triggering another set of emergency precautions. It also meant the incident has been rated at Level 4 on the International Nuclear Event Scale (INES) – an ‘accident with local consequences’.

To protect the public from potential health effects of radioactive isotopes of iodine that could potentially be released, authorities are preparing to distribute tablets of non-radioactive potassium-iodide. This is quickly taken up by the body and its presence prevents the take-up of iodine should people be exposed to it.

Over the last several hours evacuation orders for local residents have been incrementally increased and now cover people living within 20 kilometres of the power plant.

Seawater injection

The injection of seawater into the building started at 8.20pm and this is planned to be followed by addition of boric acid, which is used to inhibit nuclear reactions. Tepco had to put the operation on hold for a time when another tsunami was predicted, but work recommenced after the all-clear.

Raised temperatures

Meanwhile at adjacent Fukushima Daini, where four reactors have been shut down safely since the earthquake hit, Tepco has notified government of another emergency status.

Unit 1’s reactor core isolation cooling system had been operating normally, and this was later supplemented by a separate make-up water condensate system. However, the latter was lost at 5.32am local time when its suppression chamber reached 100ºC. This led Tepco to notify government of another technical emergency situation.

Tepco has announced it has decided to prepare for controlled releases to ease pressure in the containments of all four units at Fukushima Daini.

A three kilometre evacuation is in progress, with residents in a zone out to ten kilometres given notice of potential expansion.

Workers

A seriously injured worker was trapped within Fukushima Daiichi unit 1 in the crane operating console of the exhaust stack and is now confirmed to have died. Four workers were injured by the explosion at the same reactor and have been taken to hospital. A contractor was found unconscious and taken to hospital.

Two workers of a ‘cooperative firm’ were injured, said Tepco; one with a broken bone.

At Fukushima Daiini unit 3 one worker received a radiation dose of 106 mSv. This is comparable to levels deemed acceptable in emergency situations by some national nuclear safety regulators.

The whereabout of two Tepco workers remains unknown.

678 Comments

  1. There are a number of comments on the ‘An informed public is key to nuclear acceptance’ thread which probably should be transfered here.

    (Ed: Unfortunately I do not have the ability to transfer comments across threads, people will have to repost manually)

    Like

  2. I left a couple of questions on the appropriately named thread ‘An informed public is key to nuclear acceptance’ , and was asked to repost them here.
    (and these are serious questions, so please don’t laugh them off):

    1. I noticed that they “lost” the diesel backup units about the same time the tsunami hit the plant locations. Is it possible the debris from the tsunami jammed the cooling pump filters and intakes? What good would the backup electric system be, if the cooling water supply is blocked? It seems that they should have an alternative emergency cooling system in place.

    2. These nuclear accidents makes nuclear plants look extremely fallible.

    If one of these reactors melt down, what is the estimate for the eventual death toll, both from initial overexposure and eventually due to higher death rates due to higher radioactive levels in air, soils, and water? I would guess nuclear proponents would have these estimates at their fingertips, perhaps as a function of the amount of radioactive material released. Can one of these reactors release as much radioactive material as Chernobyl?

    3. Are these reactors finished? Do you think they will run again?

    4. Do the owners carry insurance to cover the financial costs associated with a failure? If the Gulf Coast oil spill caused over $50 B in damages, what is the likely financial damages if one of the reactors melts down? Roughly the same cost?

    I will look for your answers to these questions.

    Like

  3. Paul, thanks, at this stage here are my responses:

    1. The generators went out after a hour or so, so I doubt they were flooded. But I don’t know the full situation.

    2. No, quite the opposite. They have just performed robustly in the face of the worst earthquake ever to strike the Japanese islands.

    The risk of meltdown is extremely small, and the death toll from any such accident, even if it occurred, will be zero. There will be no breach of containment and no release of radioactivity beyond, at the very most, some venting of mildly radioactive steam to relieve pressure. Those spreading FUD at the moment will be the ones left with egg on their faces.

    I am happy to be quoted forever after on the above if I am wrong… but I won’t be.

    3. The only reactor that has a small probability of being ‘finished’ is FD unit 1. And I doubt that, but it may be offline for a year or more.

    4 Yes, they are insured. No, the costs won’t be $50 billion, more like <<$1 billion depending on what needs to be repaired, and this will all be on-site work.

    Like

  4. Press Release (Mar 12,2011)
    Plant Status of Fukushima Daini Nuclear Power Station (as of 5AM March 12th )

    http://www.tepco.co.jp/en/press/corp-com/release/11031209-e.html

    Unit 1 (shut down at 2:48PM on March 11th)
    – Reactor is shut down and reactor water level is stable.
    – Offsite power is available.
    – Control rods are fully inserted (reactor is in subcritical status)
    – Status of main steam isolation valve: closed
    – Injection of water into the reactor had been done by the Reactor Core Isolation Cooling System, but at 3:48AM, injection by Make-up Water Condensate System begun.
    – At 6:08PM, we announced the increase in reactor containment vessel pressure, assumed to be due to leakage of reactor coolant. However, we do not believe there is leakage of reactor coolant in the containment vessel at this moment.

    Unit 2 (shut down at 2:48PM on March 11th)
    – Reactor is shut down and reactor water level is stable.
    – Offsite power is available.
    – Control rods are fully inserted (reactor is in subcritical status)
    – Status of main steam isolation valve: closed
    – Injection of water into the reactor had been done by the Reactor Core Isolation Cooling System, but at 4:50AM, injection by Make-up Water Condensate System begun.
    – We do not believe there is leakage of reactor coolant in the containment vessel.

    Unit 3 (shut down at 2:48PM on March 11th)
    – Reactor is shut down and reactor water level is stable.
    – Offsite power is available.
    – Control rods are fully inserted (reactor is in subcritical status)
    – Status of main steam isolation valve: closed
    – Reactor Core Isolation Cooling System is turned off. Currently, injection of water into the reactor is done by Make-up Water Condensate System.
    – We do not believe there is leakage of reactor coolant in the containment vessel.

    Unit 4 (shut down at 2:48PM on March 11th)
    – Reactor is shut down and reactor water level is stable.
    – Offsite power is available.
    – Control rods are fully inserted (reactor is in subcritical status)
    – Status of main steam isolation valve: closed
    – Reactor Core Isolation Cooling System is turned off. Currently, injection of water into the reactor is done by Make-up Water Condensate System.
    – We do not believe there is leakage of reactor coolant in the containment vessel.

    Indication from monitoring posts installed at the site boundary did not show any difference from ordinary level. No radiation impact to the external environment has been confirmed. We will continue to monitor in detail the possibility of radioactive material being discharged from exhaust stack or discharge canal. There is no missing person within the power station.

    We are presently checking on the site situation of each plant while keeping the situation of aftershock and Tsunami in mind.

    A seriously injured worker is still trapped in the crane operating console of the exhaust stack and his breathing and pulse cannot be confirmed. A worker was lightly injured spraining his left ankle and cutting both knees when he fell while walking at the site. The worker is conscious.

    Like

  5. I have a couple of questions for people on this thread (and these are serious questions, so please don’t laugh them off):

    1. I noticed that they “lost” the diesel backup units about the same time the tsunami hit the plant locations. Is it possible the debris from the tsunami jammed the cooling pump filters and intakes? What good would the backup electric system be, if the cooling water supply is blocked? It seems that they should have an alternative emergency cooling system in place.

    I believe the main function of the diesel generators would be to keep the coolant water within the reactor itself circulating. Nor do I know of any mention of debris blocking the inlets for the secondary coolant flow. Sounds like you’re making stuff up.

    2. These nuclear accidents makes nuclear plants look extremely fallible.

    No one seems to have died yet. Apparently over a hundred people died in the oil refinery blaze in Tokyo when the earthquake struck. There also seem to be rather a lot of natgas fires burning away. This was one of the largest earthquakes in history, and most of the nuclear facilities are fine. The way they’ve performed is a tribute to the design work which has gone into them. A massive earthquake of this sort is just about the worst natural disaster you could throw at a fixed structure, and the Japanese nuclear fleet has come through it with remarkably few problems. I don’t see how that translates into ‘extremely fallible’.

    If one of these reactors melt down, what is the estimate for the eventual death toll, both from initial overexposure and eventually due to higher death rates due to higher radioactive levels in air, soils, and water? I would guess nuclear proponents would have these estimates at their fingertips, perhaps as a function of the amount of radioactive material released.

    Pretty much zero. As in the case of the meltdown at Three Mile Island, a meltdown would be most unlikely to result in the release of any significant quantity of radiation.

    Can one of these reactors release as much radioactive material as Chernobyl?

    Not by accident.

    3. Are these reactors finished? Do you think they will run again?

    The reactors are most likely OK, although I understand there is extensive damage to some parts of the rest of the plant. It will take time to repair it all.

    4. Do the owners carry insurance to cover the financial costs associated with a failure? If the Gulf Coast oil spill caused over $50 B in damages, what is the likely financial damages if one of the reactors melts down? Roughly the same cost?

    I’m not sure what the insurance arrangement for NPPs is in Japan, but any damages are likely to be limited to those of the plant itself. There shouldn’t be any external damage to be claimed on.

    Like

  6. barry: nice job here.

    I did not know that they had not invoked the ECCS.

    There’s something I don’t understand. Why were they not invoked? why ship in new portable electricity sources? can eccs work without offsite electricity or diesel generator backup?

    Like

  7. GM, the situation is not serious enough to warrant release of the ECCS. By bringing in the portable generators, they can supplement the power to the secondary system pumps and avoid a lot of later complications in the post-event cleanup/maintenance. Note that boiling water reactors like this can maintain some pump action without electricity, by using steam from the residual reactor heat to turn a turbine. Quite a neat system actually.

    Like

  8. The US news outlets are having a field-day trying to out do each other in hyperbole over these reactors. The two worse so far has been physicist Michio Kaku [ad hom deleted] saying that these reactors were a “Chernobyl waiting to happen” and that they where on the verge of going into a “China Syndrome meltdown,” at any moment, and a CNN reporter talking about the situation at Fukushima Daini Nuclear Power Station, against a backdrop of the burning Cosmo oil refinery in Ichihara city, near Tokyo.

    These are such obvious cases of bias, that I am near apoplexy.

    Like

  9. @Barry

    “Press Release (Mar 12,2011)
    Plant Status of Fukushima Daini Nuclear Power Station (as of 5AM March 12th )”

    I found that a few minutes ago and fed it into MY home, aus.politics. As one would assume, the eco-warriors are having a hissy fit.

    Like

  10. The two worse so far has been physicist Michio Kaku [ad hom deleted]saying that these reactors were… …on the verge of going into a “China Syndrome meltdown,” at any moment…

    Given the location, shouldn’t that be an “America Syndrome”?

    Like

  11. As I understand it they also have batteries for pumping coolant.

    Some of the comments I have seen around blogs and social media demonstrate the level of ignorance that exists. A wave of high speed H2O caused by nature kills probably over 1000 people and you get comments like “the biggest concern regarding this earth quake is those nuclear reactors”. I’ve been doing my bit to try and set people straight.

    Obviously getting these reactors back online as quick as possible is going to be important for the general rebuilding effort. From the perspective of energy security there will potentialy be some lessons to be learnt. But much bigger lessons regarding oil refineries.

    On a separate matter what do people make of the claims that the recent earthquake activity has been brought on by higher than usual turbulence in the sun. Presumably the mechanism proposed has something to do with some form of gravity impulse hitting the earth but I’m not sure how credible this idea is.

    Like

  12. EVACUATE DENVER!!!!
    If you live in Chernobyl the total radiation dose you get each year is 390 millirem. That’s natural plus residual from the accident and fire. In Denver, Colorado, the natural dose is over 1000 millirem/year. Denver gets more than 2.56 times as much radiation as Chernobyl! But Denver has a low cancer rate.

    Calculate your annual radiation dose:
    http://www.ans.org/pi/resources/dosechart/

    Average American gets 361 millirems/year. Smokers add 280 millirems/year from lead210. Radon accounts for 200 mrem/year.
    http://www.doh.wa.gov/ehp/rp/factsheets/factsheets-htm/fs10bkvsman.htm

    http://www.nrc.gov/about-nrc/radiation/around-us/doses-daily-lives.html

    Although radiation may cause cancers at high doses and high dose rates, currently there are no data to unequivocally establish the occurrence of cancer following exposure to low doses and dose rates — below about 10,000 mrem (100 mSv). Those people living in areas having high levels of background radiation — above 1,000 mrem (10 mSv) per year– such as Denver, Colorado have shown no adverse biological effects.
    http://www.nrc.gov/reading-rm/doc-collections/fact-sheets/bio-effects-radiation.html

    Calculations based on data from NCRP reports show that the average level of natural background radiation (NBR) in Rocky Mountain states is 3.2 times that in Gulf Coast states. However, data from the American Cancer Society show that age-adjusted overall cancer death in Gulf Coast states is actually 1.26 times higher than in Rocky Mountain states. The difference from proportionality is a factor of 4.0. This is a clear negative correlation of NBR with overall cancer death. It is also shown that, comparing 3 Rocky Mountain states and 3 Gulf Coast states, there is a strong negative correlation of estimated lung cancer mortality with natural radon levels (factors of 5.7 to 7.5).
    http://www.ncbi.nlm.nih.gov/pubmed/9753369

    Like

  13. IAEA alert log:

    Japanese authorities have informed the IAEA’s Incident and Emergency Centre (IEC) that today’s earthquake and tsunami have cut the supply of off-site power to the Fukushima Daiichi nuclear power plant. In addition, diesel generators intended to provide back-up electricity to the plant’s cooling system were disabled by tsunami flooding, and efforts to restore the diesel generators are continuing.

    At Fukushima Daiichi, officials have declared a nuclear emergency situation, and at the nearby Fukushima Daini nuclear power plant, officials have declared a heightened alert condition.

    Japanese authorities say there has so far been no release of radiation from any of the nuclear power plants affected by today’s earthquake and aftershocks.

    Like

  14. Fuel rod was exposed 90cm above the water inside the reactor core at 11:40AM. Now water for fire-fighting being injected. Fukushima No. 1 NP

    Nuclear plant safety committee confirmed reactor core now exposed 1.7meter above water, speculating now fuel rod has started to melt.

    #Nuclear plant safety committee detected cesium, a substance that is not normally detected unless, according to an expert, fuel rod melts.

    http://twitter.com/Touruma

    No idea how true it is.

    Like

  15. I hope that Twitter story is from a rumormonger, and I hope someone runs the source down and posts a followup.

    The news from the official site is bad enough:

    (From the update at the first link posted earlier)
    http://www.world-nuclear-news.org/RS_Battle_to_stabilise_earthquake_reactors_1203111.html

    “the company’s monitoring of Fukushima Daiichi 1 has separately shown an increase in radiation levels detected emerging from the plant via routes such as the exhaust stack and the discharge canal.

    Over the last several hours evacuation orders for local residents have been incrementally increased and now cover people living within ten kilometres of the power plant.

    Raised temperatures

    Meanwhile at adjacent Fukushima Daini, where four reactors have been shut down safely since the earthquake hit, Tepco has notified government of another emergency status.

    Unit 1’s reactor core isolation cooling system had been operating normally, and this was later supplemented by a separate make-up water condensate system. However, the latter was lost at 5.32am local time when its suppression chamber reached 100ºC. This led Tepco to notify government of another technical emergency situation.

    Tepco has announced it will soon begin controlled releases to ease pressure in the containments of units 1, 2 3 and 4 at Fukushima Daini.

    Like

  16. Higher sun turbulence and gravity effects have nothing whatsoever to do with the movement of lithospheric plates They have and will always continue to move. The stresses in the rocks build up and eventually movement occurs along the plate boundary or along an associated fault. The longer it takes for the movement to occur, the greater the ultimate movement and hence the greater the magnitude of the quake. In 1906, displacement along the San Andreas Fault measured 21feet. No wonder the city fell down and then burned. Following the Christchurch earthquake it was a pretty safe bet that there would be some other movement along the same plate boundary elsewhere. That’s what seems to have happened in Japan.

    Like

  17. “1. I noticed that they “lost” the diesel backup units about the same time the tsunami hit the plant locations. Is it possible the debris from the tsunami jammed the cooling pump filters and intakes? What good would the backup electric system be, if the cooling water supply is blocked? It seems that they should have an alternative emergency cooling system in place.”

    You’re thinking of the tertiary cooling system, the heatsink for the heat engine, which exchanges waste heat from the turbine out to seawater.

    This is completely different from the water that actually cools the reactor, and these reactor cooling systems aren’t dependent on drawing water in from an outside source.

    Like

  18. I did a search on the ‘exposed fuel rods’ and the story only comes up on tweets,[ad hom deleted] our friends at CNNGo said this…

    http://www.cnngo.com/tokyo/life/quake-leaves-tokyo-ites-stranded-546457

    “The top issue on everyone’s mind as of Saturday afternoon involves the Fukushima #1 Nuclear Reactor, which is reportedly leaking radioactive material in a situation highly suggestive of a meltdown. The dangerous conditions preclude direct observation, and citizens are anxiously awaiting further reports.

    According to NHK, the state news channel, one of the reactor’s fuel rod bundles has cracked, and the tips exposed by some 50 – 90 cm due to evaporation of the cooling pond. The surrounding area has subsequently been evacuated to a distance of 10 km”

    BWHAHAHAHAHAHAAAAAAAAAAA!

    That was a good trick! Getting the cooling ponds INSIDE the reactors!

    Like

  19. You’re thinking of the tertiary cooling system, the heatsink for the heat engine, which exchanges waste heat from the turbine out to seawater.

    Strictly speaking, I believe BWRs don’t have a tertiary loop. The primary loop in a BWR drives the turbine directly, so the secondary loop is the one which draws on the heat sink.

    Interesting that the Japanese nuclear authorities continue to talk about possibilities that the pundits on this site have already dismissed.

    I don’t dismiss the possibility of a Three Mile Island-style meltdown if they’re unable to provide proper cooling. Given the containment in these reactors, I very much doubt the possibility of a Chernobyl-style release.

    Like

  20. Paul, what press release, where? Link or description please?

    Google News does not find what you posted. The top hit for regular Google quoting from what you posted is the same UFO/conspiracy site I mentioned above — now at the top of the first page of hits so it’s getting propagated wildly. The second hit is the Huffington Post, home of the anti-vaccine wackywoo and other nitwittery.

    So two crap sources and no news sources.
    What source are you relying on? Why do you trust it to be giving good information? What is your source quoting from? Pointers, links, please.

    “Trust, but verify.”

    Like

  21. Reposting what I posted last night in the earlier thread: Here are diagrams of the various reactor types in use: http://www.ansn-jp.org/jneslibrary/npp2.pdf

    Details here –if you can figure out which type is being discussed; these plants have several different designs. I _think_ the big problem is the Fukushima I-1 model, judging by the date in the timeline.

    That had a simple single-loop cooling system — the one where when the condensate water pool hits 100C (starts to boil) then it’s no longer cooling the primary loop.

    Another part of this doc says the condensate pools were using sea water. I don’t find a diagram of that.

    “After driving a turbine, the steam is converted into water with a condenser (cooled by sea water in Japan), and pumped into the reactor vessel with feedwater pumps. A part of the water is sent into the reactor vessel after being pressurized with recirculation pumps installed outside of the vessel and fed into the reactor core from the bottom part of the reactor vessel with jet pumps.
    Inside of a BWR reactor pressure vessel (RPV), feedwater enters through nozzles high on the vessel, well above the top of the nuclear fuel assemblies (these nuclear fuel assemblies constitute the “core”) but below the water level. The feedwater is pumped into the RPV from the condensers located underneath the low pressure turbines and after going through feedwater heaters that raise its temperature using extraction steam from various turbine stages.
    The feedwater enters into the downcomer region and combines with water exiting the water separators. The feedwater subcools the saturated water from the steam separators. This water now flows down the downcomer region, which is separated from the core by a tall shroud. The water then goes through either jet pumps or reactor internal pumps that provide additional pumping power (hydraulic head). The water now makes a 180 degree turn and moves up through the lower core plate into the nuclear core where the fuel elements heat the water. When the flow moves out of the core through the upper core plate, about 12–15% of the volume of the flow is saturated steam….”

    Like

  22. Several sources including Reuter.
    Here is a Dow Jones version:
    http://e.nikkei.com/e/fr/tnks/Nni20110312D12JF421.htm

    Here is a MarketWatch commentary:

    March 12, 2011, 12:42 a.m. EST

    Japan warns of meltdown at quake-hit plant: Kyodo

    TOKYO (MarketWatch) — Japanese nuclear authorities warned of a meltdown Saturday of the core of a nuclear reactor at a plant in Fukushima operated by Tokyo Electric Power Corp. /quotes/comstock/64e!9501 (JP:9501 2,121, -32.00, -1.49%) , also known as Tepco, according to Kyodo News. Authorities said that there was a high possibility that nuclear fuel rods at the reactor of Tepco’s Daiichi plant may be melting or have melted, Reuters reported, citing Jiji news. The Daiichi No. 1 nuclear reactor is about 240 kilometers (150 miles) north of Tokyo. Friday’s 8.9-magnitude earthquake damaged the plant’s cooling mechanism, leading to overheating that reportedly damaged the fuel rods in the reactor’s core.

    Like

  23. Not saying it’s correct, but here’s sources for Paul’s stories

    http://www.vancouversun.com/Quake+nuke+plant+meltdown+Japan+media/4427671/story.html

    “Kyodo News agency said radioactive caesium had been detected near Fukushima plant, citing the Japanese nuclear safety commission.”

    http://www.channelnewsasia.com/stories/afp_asiapacific/view/1116036/1/.html

    “Japan’s nuclear authorities warned Saturday that quake-hit atomic plant Fukushima No. 1, about 250 kilometres (160 miles) northeast of Tokyo, “may be experiencing a nuclear meltdown”, media said.”

    Like

  24. Just saw Barry on the TV interview. He put the scare stories to bed pretty comprehensively. The newsreaders definitely thought so too. His analogy of the amount of radiation that anyone would receive standing outside the reactor for 100 days being equal to one chest x-ray was brilliant and put it in real perspective for anyone listening who was worried about the situation. He didn’t have much air time but also managed to convey that the evacuation of the areas was merely following procedural protocol arounf nuclear power plants and not indicative of a probable catastrophe.

    Like

  25. A bit more from that same ansn-jp.org document:

    “(2) Heat transfer and power control
    The heat generated in fuel rods is transferred to the reactor coolant. The magnitude of heat transferred according to the temperature difference between the heat transfer surface and the coolant has been obtained in many experiments. Since the heat transfer decreases in the transition film-boiling region in which the boiling becomes violent that could cause a burnout of fuel cladding tube, the heat transfer in the nucleate-boiling region is utilized in BWR. Therefore, the reactor operation limits are imposed on BWRs not to approach to the transition film-boiling region during normal operation and abnormal operational transients….”

    … In contrast to the pressurized water reactors that utilize a primary and secondary loop, in civilian BWRs the steam going to the turbine that powers the electrical generator is produced in the reactor core rather than in steam generators or heat exchangers. There is just a single circuit in a civilian BWR in which the water is at lower pressure (about 75 times atmospheric pressure) compared to a PWR so that it boils in the core at about 285°C. The reactor is designed to operate with steam comprising 12 to 15% of the volume of the two-phase coolant flow (the “void fraction”) in the top part of the core, resulting in less moderation, lower neutron efficiency and lower power density than in the bottom part of the core….

    … Changing (increasing or decreasing) the flow of water through the core is the normal and convenient method for controlling power. When operating on the so-called “100% rod line,” power may be varied from approximately 70% to 100% of rated power by changing the reactor recirculation flow by varying the speed of the recirculation pumps. As flow of water through the core is increased, steam bubbles (“voids”) are more quickly removed from the core, the amount of liquid water in the core increases, neutron moderation increases, more neutrons are slowed down to be absorbed by the fuel, and reactor power increases. As flow of water through the core is decreased, steam voids remain longer in the core, the amount of liquid water in the core decreases, neutron moderation decreases, fewer neutrons are slowed down to be absorbed by the fuel, and reactor power decreases.
    Steam produced in the reactor core passes through steam separators and dryer plates above the core and then directly to the turbine, which is part of the reactor circuit. Because the water around the core of a reactor is always contaminated with traces of radionuclides, the turbine must be shielded during normal operation, and radiological protection must be provided during maintenance. Most of the radioactivity in the water is very short-lived (mostly N-16, with a 7 second half life), so the turbine hall can be entered soon after the reactor is shut down.”

    Like

  26. NYT puts a name on the quotes:
    http://www.nytimes.com/2011/03/13/world/asia/13nuclear.html

    “Ryohei Shiomi, an official with Japan’s nuclear safety commission, said that a meltdown was possible at one of the two Daiichi reactors, The Associated Press reported. Japanese television reported that the country’s Nuclear and Industry Safety Agency said it had detected cesium near one of those reactors.

    Naoto Sekimura, a professor at Tokyo University, told NHK, Japan’s public broadcaster, that “only a small portion of the fuel has been melted….”
    ——-

    No press release at the TEPCO site, here’s the page to check for their news releases:
    http://www.tepco.co.jp/en/press/corp-com/release/index-e.html

    Like

  27. PaulK2
    There are a lot of ifs in the report you linked

    “Hideyuki Ban, the co-director of Citizens’ Nuclear Information Center, said, “The Japanese government’s Nuclear and Industrial Safety Agency has said that if the water level can be raised to cover the fuel rods, they can keep the situation under control, but if the water cannot cover the fuel, the damage will become more severe, and that means radioactive materials will be released.”

    “If damage expands, cesium or other radioactive materials may be released not only inside the containment dome but also into the environment,” he said.”
    This seems to have produced misquoting on some other sites to the point where cesium HAS been released. Surely you know how a story changes as it passes from mouth to mouth. Let’s wait for official confirmation by the appropriate authorities shall we?

    Like

  28. And if you look at the footnotes to the Wikipedia article, if you can read Japanese, they actually cite sources for the stories and link to them. Good.

    This info: “During the afternoon of March 12, the Nuclear and Industrial Safety Agency announced that part of a cesium rod appeared to have melted, but the NHK reported that the rest of the fuel had cooled and there was no reason for alarm.[24]”

    This source:
    http://www3.nhk.or.jp/news/html/20110312/t10014623511000.html

    Like

  29. If cesium has been detected in the coolant water, then the integrity of at least some of the fuel rods has been breached. Given the information that the coolant is only covering the bottom 2/3 of the fuel rods, it shouldn’t take long for the structural integrity of the top portion of the fuel rods to fail.

    If the fuel rods fail and fall, will the control rods still be able to control the reactor?

    Like

  30. Now this from Business Week — which I doubt makes sense:
    http://www.businessweek.com/news/2011-03-12/japan-reactor-rods-may-have-started-to-melt-agency-says.html

    “Tokyo Electric earlier said …. Temperatures in the control room rose to higher than 100 Celsius (212 Fahrenheit), said Naoki Tsunoda, a company spokesman.”

    Hard to believe that’s right. 100 C is the temperature given earlier as a problem for the condensing water pool. But the control room??
    Can’t be right. That’s nightmare material.

    Like

  31. > Given the information that the coolant is only
    > covering the bottom 2/3 of the fuel rods

    Given that? By whom? Where? “Press releases say” is not a source. Sources, man, give us your sources. Otherwise you’re just copypasting stories and that makes everyone dumber.

    Take the “100 C” report above. What’s boiling temperature? Look before that for the “evaporation of the cooling pond” — now that makes sense, and it is indeed on the path to a major failure.

    Could happen. But they had not triggered the last-ditch emergency cooling system — at last report.

    There’s nothing about this in any press release file I can find. If it’s true, someone will know where the story started.

    Ask who says and where you can check.

    Like

  32. > botched translation

    You bet. [ad hom deleted]Plus the honestly fearful who don’t know how to look stuff up.

    Seriously, if you read Japanese, please look at the Japanese sources that Wikipedia cites and help us out — heck, help Wikipedia out with better translations.

    Like

  33. Suspending venting due to high radiation level in the vented gases:

    Venting air from reactor container suspended

    The operation at Fukushima No.1 plant to lower pressure of the containment vessel has been suspended due to high radiation levels at the site.
    http://www3.nhk.or.jp/daily/english/12_38.html
    Pressure of the reactor container is rising as its cooling system became dysfunctional due to a blackout and power generator breakdown. This has raised concern about possible damage to the container.

    The power station’s operator, Tokyo Electric Power Company, began to vent air from the reactor container at 9AM on Saturday.

    Under the plan, 2 valves close to the container would be opened manually, but radiation level on the second valve was found higher than expected.

    The operation has been suspended because of the possibility that workers could be exposed to radiation. The utility is reportedly studying how to open the valve by replacing workers at a short interval, or using electric remote control.

    The Nuclear and Industrial Safety Agency says if radioactive substance is released in the air, safety of residents evacuated beyond a 10-kilometer radius from the No.1 reactor will be ensured.

    Saturday, March 12, 2011 13:09 +0900 (JST)

    Like

  34. Paul, the reactor is already subcritical and the control rods are home. NOTHING will restart the reaction now.

    I just wrote this in response to a friend who said this via email:

    So this is interesting that the Japanese reactors need power to pump cooling water and are in danger of melt down now if I am to believe the news. How can that be since the plant generates it’s own power? So how can it be in danger of meltdown? Would a gen iii plant have the same problem? Why didn’t they put in the control rods to shut down the reactor?

    1. The reactors shut off in the event of a situation like this – control rods are dropped. Power levels drop to about 5%.
    2. The plant is then no longer generating electricity and requires and external source such as a diesel generator to provide power to pumps.
    3. The tsunami seems to have damaged the diesel generators, so they had to fly in some new backup power units.
    4. The meltdown risk is if too much steam is vented from the primary circuit such that the fuel rods are exposed. This may have happened for a short time, leading to some melt of the clad (due to decay heat from the fission
    products) but nothing is confirmed at this stage (i.e. nothing from TEPCO).
    5. AP1000 has additional systems to make this less likely.
    6. Such a potential situation (fuel melt due to loss of coolant via venting) could not happen in the IFR as the fuel would remain passively cooled by the sodium.

    Like

  35. Dow Jones is source for information on 1/3 of fuel rods exposed (I posted link earlier):

    Saturday, March 12, 2011
    Nuclear Authorities: Nuclear Reactor Facing Threat Of Meltdown

    TOKYO (Dow Jones)–Japanese nuclear authorities said Saturday afternoon the Fukushima Daiichi No. 1 nuclear reactor was experiencing the threat of a meltdown after Friday’s massive earthquake damaged the cooling system and that outside water was being poured into the reactor to cool it down.

    “If the water level remains at this level, the reactor core might be damaged, but we are now pouring water into the reactor to prevent it from happening,” a spokesman for Tokyo Electric Power Co. (9501) told Dow Jones Newswires. TEPCO is the owner of the plant, which is located 150 miles, or 240 kilometers, away from Tokyo.

    A portion of the reactor’s fuel rods, which create heat through a nuclear reaction, have become exposed due to the cooling-system failure. The spokesman for TEPCO said 1.5 meters of the 4.5 meter long fuel rods were potentially exposed.

    Loss of cooling water resulted in a near meltdown of the Three Mile Island reactor in Pennsylvania in 1979, the worst nuclear incident in U.S. history.

    If coolant isn’t restored, extreme heat can melt through the reactor vessel and result in a radioactive release. Reactors have containment domes to catch any release. But there is always the chance that an earthquake could create cracks or other breaches in that containment system.

    Hideyuki Ban, the co-director of Citizens’ Nuclear Information Center, said, “The Japanese government’s Nuclear and Industrial Safety Agency has said that if the water level can be raised to cover the fuel rods, they can keep the situation under control, but if the water cannot cover the fuel, the damage will become more severe, and that means radioactive materials will be released.”

    “If damage expands, cesium or other radioactive materials may be released not only inside the containment dome but also into the environment,” he said.

    Like

  36. Update from TEPCO:

    Press Release (Mar 12,2011)
    Plant Status of Fukushima Daini Nuclear Power Station (as of 1PM March 12th )

    Unit 1 (shut down at 2:48PM on March 11th)
    – Reactor is shut down and reactor water level is stable.
    – Offsite power is available.
    – At 8:19am, there was an alarm indicating that one of the control rods was not properly inserted, however, at 10:43am the alarm was automatically called off. Other control rods has been confirmed that they are fully inserted (reactor is in subcritical status)
    – Status of main steam isolation valve: closed
    – Injection of water into the reactor had been done by the Reactor Core Isolation Cooling System, but at 3:48AM, injection by Make-up Water Condensate System begun.
    – At 6:08PM, we announced the increase in reactor containment vessel pressure, assumed to be due to leakage of reactor coolant. However, we do not believe there is leakage of reactor coolant in the containment vessel at this moment.
    – At 5:22AM, the temperature of the suppression chamber exceeded 100 degrees. As the reactor pressure suppression function was lost, at 5:22AM, it was determined that a specific incident stipulated in article 15, clause 1 has occurred.
    – We decided to prepare implementing measures to reduce the pressure of the reactor containment vessel (partial discharge of air containing radioactive materials) in order to fully secure safety. This preparation work started at around 9:43am.

    Unit 2 (shut down at 2:48PM on March 11th)
    – Reactor is shut down and reactor water level is stable.
    – Offsite power is available.
    – Control rods are fully inserted (reactor is in subcritical status)
    – Status of main steam isolation valve: closed
    – Injection of water into the reactor had been done by the Reactor Core Isolation Cooling System, but at 4:50AM, injection by Make-up Water Condensate System begun.
    – We do not believe there is leakage of reactor coolant in the containment vessel.
    – At 5:22AM, the temperature of the suppression chamber exceeded 100 degrees. As the reactor pressure suppression function was lost, at 5:22AM, it was determined that a specific incident stipulated in article 15, clause 1 has occurred.
    – We decided to prepare implementing measures to reduce the pressure of the reactor containment vessel (partial discharge of air containing radioactive materials) in order to fully secure safety. This preparation work commenced at around 10:33AM and completed at 10:58AM.

    Unit 3 (shut down at 2:48PM on March 11th)
    – Reactor is shut down and reactor water level is stable.
    – Offsite power is available.
    – Control rods are fully inserted (reactor is in subcritical status)
    – Status of main steam isolation valve: closed
    – Reactor Core Isolation Cooling System is turned off. Currently, injection of water into the reactor is done by Make-up Water Condensate System.
    – We do not believe there is leakage of reactor coolant in the containment vessel.
    – We decided to prepare implementing measures to reduce the pressure of the reactor containment vessel (partial discharge of air containing radioactive materials) in order to fully secure safety. This preparation work commenced at around 12:08PM and completed at 12:13AM.
    – At 12:15PM, the reactor achieved cold shut down.

    Unit 4 (shut down at 2:48PM on March 11th)
    – Reactor is shut down and reactor water level is stable.
    – Offsite power is available.
    – Control rods are fully inserted (reactor is in subcritical status)
    – Status of main steam isolation valve: closed
    – Reactor Core Isolation Cooling System is turned off. Currently, injection of water into the reactor is done by Make-up Water Condensate System.
    – We do not believe there is leakage of reactor coolant in the containment vessel.
    – In order to cool down the reactor, injection of water into the reactor had been done by the Reactor Core Isolation Cooling System, however, At 6:07AM, the temperature of the suppression chamber exceeded 100 degrees. As the reactor pressure suppression function was lost, at 6:07AM, it was determined that a specific incident stipulated in article 15,clause 1 has occurred.
    – We decided to prepare implementing measures to reduce the pressure of the reactor containment vessel (partial discharge of air containing radioactive materials) in order to fully secure safety. This preparation work commenced at around 11:44AM and completed at 11:52AM.

    Indication from monitoring posts installed at the site boundary did not show any difference from ordinary level.

    No radiation impact to the external environment has been confirmed. We will continue to monitor in detail the possibility of radioactive material being discharged from exhaust stack or discharge canal.

    There is no missing person within the power station. We are presently checking on the site situation of each plant while keeping the situation of aftershock and Tsunami in mind. A seriously injured worker is still trapped in the crane operating console of the exhaust stack and his breathing and pulse cannot be confirmed. Currently, the rescue efforts are under way. A worker was lightly injured spraining his left ankle and cutting both knees when he fell while walking at the site. After medical treatment, the worker is resting in the office.

    Like

  37. Remember that there are two Fukushima nuclear power stations. Daini and Daiichi.

    “All 6 units of Fukushima Daiichi Nuclear Power Station have been shut down.

    Unit 1(Shut down)
    – Reactor has been shut down and steam in reactor has been cooled by isolation condenser, but it is now stopped. Because pressure level in reactor containment vessel is increasing, following the national government instruction, we are implementing a measure to reduce the pressure of the reactor containment vessels in order to fully secure safety.
    Reactor water level is decreasing, we will continue injecting water step by step.

    http://www.tepco.co.jp/en/press/corp-com/release/11031219-e.html

    Like

  38. Thanks Barry for bypassing the “Major Media” with their [ad hom deleted] such as Michio Kaku.

    Speaking as a professional scientist, I support DV8XL’s assessment of Kaku. Much as I love the documentaries on the Discovery channels, I cringe when they feature Kaku [ad hom deleted].

    When the dust settles, I expect your credibility will shine compared to the likes of him.

    Like

  39. Whoops….
    CH9 just got a LOT worse. 18:30 news.

    “Frantically trying to avoid a catastrophic MELT DOWN”.

    “RADIATION levels over 1000 times over the SAFE threshold”

    “PEOPLE evacuated as DEADLY RADIOACTIVE GAS is vented into the atmosphere”

    Sheesh…..

    Like

  40. Quite amazing,[ad hom deleted] who appear out of the woodwork in a situation like this. I saw the same thing on The Oil Drum when the Deepwater Horizon exploded.

    Most of the comments then were complete and utter crap.This Japan earthquake is the same sort of situation only we have the antinuclear propagandists trying to cash in.

    Kiddies,why not just let the situation clarify and then draw conclusions. It seems to me that the Japanese reactors are in competent hands,even in an emergency like this.

    Like

  41. To answer some disputes in this thread

    There are two parts of the Fukushima plant, separated by a few miles. Daiichi (1) has 6 reactors (three were out for maintenance), and Daini (2) has 4.

    Fukushima Daiichi #1 (first phase, first reactor) is a GE BWR/3. IAEA publishes a table of these things:

    http://www-pub.iaea.org/MTCD/publications/PDF/CNPP2010_CD/pages/AnnexII/tables/table2.htm

    I think it has a Mark 1 containment (should double check this)

    Reputable sources are reporting cesium detected outdoors, e.g. the NY Times:

    http://www.nytimes.com/2011/03/13/world/asia/13nuclear.html?_r=1&hp=&pagewanted=all

    (But I do not believe (though I am no expert) that fuel must melt for cesium to be released — I think fuel rod rupture is enough.)

    The claims of 100 °C control room temperatures are obvious mistranslations. If you cross-check with TEPCO press releases, that temperature probably refers to the pressure supression vessel.

    Reports that fuel rods were exposed are scattered and seem unreliable.

    http://e.nikkei.com/e/fr/tnks/Nni20110312D12JF423.htm

    “…said one observer”

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  42. The head of the finnish regulatory agency STUK has just commented the situation in Japan and he thinks this will be the worst nuclear accident after Chernobyl. He says there was a hydrogen explosion and since the reactor is so old the containment building is insufficient [unsubstatiated personal opinion deleted] The rescue effort will continue for months.

    Like

  43. Unfortunately as with Christchurch structure collapses the Fukushima nuclear has become critical as well as the ‘quake releasing 8,000 times the energy of Christchurch shallow event; generation of damage seems to be continuing and any knowledge of structures would tell one that is a bad situation. 7.2 6.6 last night UK time 8.9 and many small events continuing.Our thoughts with Japan nuclear and safety officers. Mike

    Like

  44. ..Futhermore Mr Laaksonen (head of stuk) strongly criticized the insufficient planning with respect to the loss of grid power to run the cooling. He felt that this was a weakness that japanese were well aware of, but had not yet tackled. He also mentioned that USA has several old nuclear power plants with similar weaknesses.

    Like

  45. The lack of information coming out of the Fukishima-Daiichi plant is worrisome. It may indicate the command structure at the facility has been decimated. At this point it is unlikely that the plant control systems and personnel are still intact.

    Since the coolant systems seemed to be under manual control prior to the accident, how the plant will be controlled at this point is highly questionable.

    Like

  46. @ Jani-Petri Martikainen

    How absurd is this situation? How long the cooling system (via turbine spin down) could run with loss of power was exactly the experiment they were running at Chernobyl!

    Why is it the issue hasn’t been addressed comprehensively at every single NPP?

    Like

  47. esquilax,

    The cooling system at no western nuclear plant is ran by the turbines spinning down. i.e. this failure has NOTHING to do with Chernobyl. The cooling systems can be ran for 8 hours on batteries (which is what they did ), off-site power or diesel generators.

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  48. @Scott While you are correct, that is is not similar to Chernobyl, the faith put on the diesel generators has been proven faulty. What I understood is that the NPP was not properly setup to quickly switch to off-site generators when osite ones failed.

    Like

  49. Now is the time to be trumpeting the remarkable success of nuclear power in the face of natural disaster. Such survival in the face of this most savage event, such temporary faults! Nuclear has survived its most severe test yet, confounding its naysayers and pleasing its designers.

    Every hysterical assertion could be countered by referring to the much greater damage done to its rival power sources. Ask what is the condition of the brickwork around coal-fired power stations, or the railways supplying them with coal? How intact are the pipelines supplying methane to factories and homes of a hundred million people? What would be the condition of rooftop glass-covered solar panels? Where would the offshore wind turbines be now? Would the prised-open fractures of the geothermal source stay open enough to continue to supply steam?

    The context of widespread damage to other structures and processes does represent a major challenge to the Japanese response. Consider for example, damage to industrial brickwork including factories, offices and homes, rupturing of pipelines including water and sewerage, the breaking of landline communications and damage to roadwork. As far as toxicity is concerned, consider the spills throughout the chemical engineering plants across Japan. They have plenty to worry about already.

    However, by the time the Japanese people begin what must be a massive recovery programme, it will be nuclear energy first back on deck to power the heavy lifting.

    Like

  50. Understandably there is a lot of confusion going on with the various news sources misinterpreting opinions as facts…

    So, more likely explosion was to do with a secondary structure than hydrogen related? I’ve seen nothing solid to the contrary at this stage, only speculation.

    Like

  51. Roger Clifton: I don’t think you have to be a nuclear hater to realise that the industry is pretty unique in its potential for disastrous consequences should something go badly wrong. If a wind farm is destroyed, then that’s a loss to the grid and presumably the government or company that put them up. But it won’t result in a great many wind turbine-related deaths. Ditto for solar and wave — though not so much for coal or oil.

    Now, in this case the great hope is that the Japanese authorities have things under control, and that the design of the reactors and the safety planning stands up. And there’s an awful lot of hysteria out there.

    That doesn’t negate basic concerns about nuclear energy.

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  52. News coming in indicates that this was an ignition of hydrogen, which caused the explosion and collapse of the roof of the outer reactor building. I strongly suspect that the steel reactor vessel remains intact, which is good news. This is an older design, where the containment is fully internal , rather than being part of the external building shell. Look at the diagram I’ve included in the top post (via Capacity Factor), and you can get a better idea of what I mean.

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  53. Explosion
    Television cameras trained on the plant caputured a dramatic explosion surrounding unit 1 at around 6pm. Amid a visible pressure release and a cloud of dust it was not possible to know the extent of the damage. The external building structure does not act as the containment, which is an airtight engineered boundary within. The status of the containment is not yet known.

    http://www.world-nuclear-news.org/RS_Battle_to_stabilise_earthquake_reactors_1203111.html

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  54. It’s difficult to tell exactly what’s happening in the explosion vid. It seems to me as if the explosion may have been centred on the turbine hall rather than the reactor containment building.

    Of course, in a BWR, the primary coolant loop connects both of these.

    The Japanese authorities have extended the evacuation zone to 20km.

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  55. Also if they had containment hyrdrogen recominers they likely did not have power to operate them. The video sure appears to be a Reactor Building explosion. Turbine structure would be the lower height building.

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  56. Thanks and well done Barry. Much attention given to controlled venting from nuclear power stations. Acrid plumes of smoke from burning oil refineries does not seem to raise eyebrows. Nuclear is still a sexy hazard, quite clearly. Keep the facts coming, we need them.

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  57. Honestly, anyone claiming “victory” from any side of the argument on this less than 48 hours after the earthquake is just plain silly. Anyone who claims they know exactly what has happened and will happen from here is either guessing, lying, or both.

    Like

  58. Here is the report from the BBC website:
    “Government spokesman says the nuclear reactor container at the Fukushima-Daiichi plant has not been damaged, and the level of radiation has dropped following the explosion earlier on Saturday, AFP reports.”

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  59. I’m not convinced the explosion was centred on the reactor building. From what I can make out, it looks as if the explosion starts behind the squarish containment building, and much of the cloud emerged from where the turbine hall would be.

    I could be wrong, and it may well have been a hydrogen explosion in any case.

    Is it confirmed that the reactor building was destroyed? It seems largely intact in the video even after the explosion.

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  60. Boy, did I pick the wrong time to come back to the discussion on NP.

    Even though a series of aging NPPs survived a massive earthquake, even though no serious amount of radiation was released, and no one will be killed, i’m worried this might be the end. People may simply read headlines like ‘Is this another Chernobyl’ and their views on nuclear power may be seriously tainted, all over the world.

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  61. From what I can see in the pictures, similar reactor designs and reports. It is the reactor building. If it was just the interface (steam tunnel) it would be only the side back towards the lower building.
    Lets just hope they can continue to inject what they can and the containment was not damaged.

    Need power to flood up the containment using ECCS pumps (large volume) and/or initiate suppression pool cooling to allow SRV flow cooling to be become effective again. It takes alot of water if they must flood the containment for cooling.

    I’d say if rad levels are dropping, the contaiment is likely still in tact with some fuel failure having occurred.

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  62. I doubt it Huw. When the dust settles, people will realise how well the Japanese reactors — even the 40 year old one — stood up to this incredibly energetic earthquake event. Meanwhile, China, India, Korea etc. will keep building lots of reactors. Those who don’t, well, they’ll continue to be utterly wedded to burning fossil fuels with essentially no other options. There’s this old thing called ‘reality’ that never goes away, despite how annoying it can be to some, at times.

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  63. I get a NHK feed and watched the press conference from Tokyo Electric.

    1) It was a combination of steam and hydrogen that caused the explosion. What we saw wasn’t a building but a steel frame with concrete panels.

    2) Nuclear container was not damaged

    3) Both the radiation level and pressure inside container at reactor 1 have been steadily decreasing since the explosion.

    4) Level was 1,015 microverts at the time of explosion, they been measuring the levels regularly and had dropped to 800 by 5 pm, and 600 by 7 pm.

    5) They are going to let in sea water to help cool reactor 1 down.

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  64. Barry, I seriously hope your right. I’m just hoping this wont impact any new build plans in Europe where there arn’t any major fault lines. I’m pretty sure there’s none in Australia either.

    Did anyone read that comment by Walt Patterson on the BBC article ‘This is starting to look a lot like Chernobyl’ – WHAT?! Which Chernobyl were you looking at?

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  65. Don’t forget that if the reactor escapes without releasing a huge amount of radiation, then it will be forever proven that even a 40 year old reactor can survive an 8.9 earthquake followed by a massive tsunami. It’s not the end of the world.

    Like

  66. Something interesting from a friend of mine, who’s a professor of geophysics:

    The recent Japanese earthquake was a very large one, large enough to be listed in the top 10 in the past century. See:
    http://www.infoplease.com/ipa/A0763403.html

    The largest event we ever recorded was the 1960 M9.5 or 9.6 Chilean earthquake. The 1964 Good Friday event in Alaska was quite a bit smaller at 9.2.

    At the risk on sounding pedantic, I have to indicate that magnitude is a terrible way to measure the size of an earthquake. The Body wave magnitude “saturates” at about 7.5, because the wavelengths of the seismic waves used for that (1 hz P waves) is only about 10 km , so that the amplitudes are controlled by the first 10-20 km of rupture. The surface wave magnitude is based on 20 sec period Rayleigh waves, and is sensitive to a much larger portion of the initial rupture. It saturates around 8.5. After that one has to go to free oscillations of the planet (first observed in 1960), and the gravest modes have periods of 10 minutes to one hour. that will yield a very good estimate of the so-called “moment” of the earthquake. the magnitudes listed in the site above are scaled form moment estimates.

    The problem is that P-waves take about 20 minutes to travel to distant seismic stations, so in the first hour after an event, magnitude estimates tend to be low. After a couple of hours, surface waves have been recorded and analyzed, and the magnitude estimate goes up if the event was big. After a couple of days, free oscillations have been recorded (they will be recorded for several weeks) and a much better magnitude becomes available…. and it can be much larger. However, this does not help with tsunami warnings, of course.

    Another issue is that amplitude-based scales are not very good at telling the story. For each unit step in magnitude, the energy of the event changes by a factor of 30. So a M9.6 event is 30 times more energetic than a M8.6 event. But the number of event drops by a footer of 10 for each increase of on unit in magnitude. Thus it is practically impossible to implement a scheme to “relieve stress” by triggering numerous events of acceptable size. It would take 27,000 M5.6 events to equate a M8.6 one, yet only 1,000 occur in nature.

    It is now possible to use continuously recording GPS stations to get an estimation of the static displacement (zero-frequency) in real time. This is not yet done operationally, unfortunately.
    look at the solutions derived by Europeans for this event at http://igscb.jpl.nasa.gov/pipermail/igsmail/2011/006350.html

    This offers great promise for tsunami warnings and immediate reaction to very large events.

    Finally, the problems with reactor safety require knowing the actual spectrum of the vibrations. Large structures can be damaged by relatively “low” frequency shaking, while pipes, etc may have resonances at much higher frequencies. Even a relatively small event can be very dangerous, of course, if it is close enough and pumps much energy into critical frequencies. A big difference with large events is that the shaking duration is much longer so that fatigue issues become important.

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  67. I’m adding my name to this group to monitor how this event will affect the NRC approval time process time for STP 3 and 4 which has already been delayed 18 months to review a redesign that was initiated because of an NRC concern about terrorism. That concern led to an increased thickness of the containment vessel. However the NRC said that the increased weight causes an earthquake problem and wants the extra 18 months to review the new design change. Now that the earthquake and tsunami have happened we are likely to see even more delays. This is reminiscent of delays in the 1980’s. I thought we were past that problem but apparently not.

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  68. “Edano said it would take about five to 10 hours to fill the reactor core with sea water and around 10 days to complete the process.”

    What process will take the 10 days? Decay heat to reduce?

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  69. Likely using portable pumps for the seawater with limited capacity. If the core stays covered and they keep adding water it will be cooled.
    Pump ideally to vessel and open an SRV to containment. Increases size of pool volume for those that understand pool boiling calculations.
    While this is going on I’m sure they will try and get power back to use the larger volume ECCS pumps if not damaged to move water and establish real cooling.
    Covering the damaged fuel also allows for some scrubbing of the fission product gases that you must vent while flooding.

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  70. i have posted on Nuclear Green a very preliminary assessment of the some nuclear safety issues posed by the Fukushima Dai-ichi explosion, and the possibility of further safety related events. Some recent reactor designs, notably the AP-1000, are likely to have survived the earthquake with passive cooling systems in tact. Other designs are more questionable. Among potential Generation IV reactor designs, Molten Salt Reactors are likely to perform very well in similar situations.

    http://nucleargreen.blogspot.com/2011/03/nuclear-safety-and-fukushima-dai-ichi.html

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  71. Cesnium and Iodine are fission product gases and indicate fuel cladding failure of some degree. Facts are the levels are dropping as venting is stopped so that’s good. Levels don’t appear to be that of gross cladding failure.
    Iodine is bad as it concentrates in your thyroid which is why they dispense Iodine tablets. Try to saturate the thyroid with non radioactive Iodine so you don’t load up the activated Iodine.

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  72. esquilax please settle down with the histrionics and could you try to be a little more mature?

    Not only are the radiation and pressure slowly decreasing the container is intact. They did deal with the heat issue by venting the steam.

    And now they’re using sea water to help it cool as well.

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  73. in the reuters article, there was mention of boric acid to prevent criticality.

    I thought a criticality accident was ruled out with water moderated reactors. is there a failure to distinguish criticality accidents (chernobyl, right?) from LOCAs?

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  74. Nikkiei, they vented the containment to prevent containment failure due to overpressure. Once they lost suppression capability due to temperature of the suppression pool, containment pressure had to follow temperature. It is better to release a small amount of gas to relieve pressure, than fail the containment and release forever….

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  75. I’m not sure why they are borating, unless possibly some control rods failed to insert. Failure of more than one to insert would by standard procedure require boration to ensure shutdown margin when fully cooled down worst case. Or they are just overkilling by borating.

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  76. Don’t confuse the fact that a voided core, loss of moderator will shutdown the reaction but with certain fuel damage. You want to keep the fuel covered and cool to limit fuel damage. Voiding the core is the ultimate poison but will melt the fuel too.

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  77. Pingback: Get Your Hands Dirty! | MK is Stacked

  78. As a professional physicist, I am stunned by two things about this thread. The first is the degree of complacency exhibited by nuclear proponents, [unsubstantiated personal opinion deleted]Complacency in designers of any critical system is a very bad thing. The second is the [unsubstantiated personal opinion deleted] eminating from those apparently against next gen nuclear and the rush to sensationalism. As an independent I have been stunned to see nuclear plant operations so ‘easily’ compromised and the situation progress to a hydrogen explosion. None of that is normal and should not occur in the current situation. Tsunami and large eathquakes were design requirements and the plants have not met those requirements. if next gen nuclear is to be acepted then the industry and its experts need to put the complacency away and operate/design instead with a healthy dread for nuclear fission. We expect nothing less of you.

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  79. Source: http://blogs.aljazeera.net/live/asia/live-blog-japan-earthquake

    The operator of the Fukushima nuclear power plant, Tokyo Electric Power Co, will fill the leaking reactor with sea water to cool it down and reduce pressure in the unit, a government spokesman says. Cabinet secretary Yukio Edano said:

    The nuclear reactor is surrounded by a steel reactor container, which is then surrounded by a concrete building.

    The concrete building collapsed. We found out that the reactor container inside didn’t explode.

    Authorities earlier warned of a reactor meltdown at the reactor, damaged when a massive earthquake and tsunami struck the northeast coast, but said the risk of radiation contamination was small.

    We’ve confirmed that the reactor container was not damaged. The explosion didn’t occur inside the reactor container. As such there was no large amount of radiation leakage outside.

    At this point, there has been no major change to the level of radiation leakage outside, so we’d like everyone to respond calmly.

    We’ve decided to fill the reactor container with sea water. Trade minister Kaieda has instructed us to do so. By doing this, we will use boric acid to prevent criticality.

    It is expected to take between five and ten hours to fill the reactor core with sea water – and around ten days to complete the process.

    Edano said due to the falling level of cooling water, hydrogen was generated and that leaked to the space between the building and the container and the explosion happened when the hydrogen mixed with oxygen there.

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  80. If this is truely a Mark 1 Containment (Torus) they likely had a direct vent from the Torus to the stack. This was a mod to the Mark 1 Containments. If my memory is correct it went to the stack via the Reactor Building ventilation system.
    That would have been the way they would have tried to reduce Containment/Torus pressure once the Torus temperature got too high to condense steam from the SRVs. As they did this the H2 concentration would have risen that they were venting.
    Mixed this with Reactor Building ventilation to form an explosive concentration. Without power available they likely didn’t have Reactor Building ventilation fans operating. Fans in service would have provided large volumes of air dilution of the H2 concentration. Bad situation and ultimately what likely caused the explosion.

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  81. I am not complacent about the seriousness of this event. But, they seem to be handling it text book for severe accident management. When the details emerge I’m sure they are dealing with things way beyond the design basis of the plant (station blackout + > DBA earthquake + > design Tsunami)

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  82. . There is no credible risk of a serious accident.

    Sorry, evacuation of 40,000 people from a 10km exclusion zone is ITSELF a very serious accident and confirmatin that authorities believe there to be a credible risk of much worse.

    Spinning will not change the impact of this on public perceptions even if there ends up being negligible radiation leakage and no direct deaths.

    Nuclear fission is still the only plausible available replacement for fossil fuels.

    Can we now agree that weakening regulation and safety requirements is NOT going to be a politically viable approach to getting costs below coal (whether or not you still prefer that it should be)?

    If so can we now agree on supporting massive R&D to get cheaper clean energy, including R&D on making nuclear fission both cheaper and safer in earthquake zones as well as many other types of R&D.

    Still seems obvious to me that is a much more viable strategy than trying to get a nuclear rollout while it is still more expensive than coal. Does it now also have more appeal to others?

    Note that massive R&D pwould include the necessary preliminaries for starting nuclear research and education institutes that will be neded for trained staff etc and of demonstration plants for them to work with. The other approach has delivered nothing at all so far.

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  83. Today’s Top Stories From Nuclear Townhall:
    • Pressure In Fukushima Daiichi Reactor Said To Be Decreasing
    • Japanese Official Says Pumping System Caused Collapse At Nuclear Plant
    • TEPCO Confirms Venting Of Unit 1, ‘Reactor Not Affected’ By Explosion
    • Japan To Fill Leaking Nuclear Reactor With Sea Water
    • Serious Damage Unlikely To Nuclear Reactor Container
    • Japanese Authorities: Explosion Did Not Occur At Fukushima Reactor
    • Building Collapse, Smoke At Daiichi #1 Complex
    • Japan Orders Evacuation Near 2nd Nuclear Plant
    • How To Help Japan Earthquake Relief
    • Japan Works To Stabilize Reactors In Wake Of Earth Shock

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  84. While I am definitively a supporter of Nuclear Power in general, Fukushima is an example of the [ad hom deleted]
    of nuclear safety officials. The apparent failure of the Mark I BWR containment is not surprising, as multiple studies support the idea that a Mark I is woefully inadequate for even a DBA LOCA (look at NUREG-1150, something like 90% prob of containment failure). This has been known since the 80s, the fact that NRC keeps on re-licensing Mark I containment plants is simply unforgivable. I am truly worried that with the integrity of the drywell compromised and a apparent core melt beginning, there could be radiation release well beyond design basis.

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  85. IF it was damaged and spent fuel pool level lost, RAD levels would be sky high. That’s all I can speculate on that. There are no reports of extreme RAD levels, yet….
    As long as they can keep level in the pool even without a secondary containment structure (Rx Building and it’s ventillation system), it’s not good, but it still should protect the public.

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  86. Let’s see how long the hysteria will last this time.

    US went over to coal and gas after Three Mile Island. After Chernobyl, the rest of the world made the same.

    If there is going to be an environmental disaster caused by Japans accident, this is how it will happen – more fossil fuels.

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  87. The question is, ultimately, what else was damaged in the failure of the drywell? Vital components of the ECCS (emergency core cooling system), including HPCI, LPCI and RCIC are located in the drywell, and most likely, inoperable. They could also be losing cooling water inventory via a break through the main steam line, although depending on the location of the MSLIV, they might be ok. One also has to wonder if the integrity of the suppression pool (torus) is ok, because if the drywell failed, it is highly likely that the torus is damaged. This is very dangerous, because the supression pool ventilation network, which directly connects to the primary containment, which means the primary containment is essentially connected to the atmosphere! Also it is highly likely that normal reactor pressure control is severely limited because of the destruction of the torus. Ultimately, Fukushima is in a beyond-DBA LOCA and has already began a core melt, and the radiation release will most likely be in excess of three mile island, considering the loss of containment. If they dont get reactor cooling under control (which right now is now trivial task), they could be looking at a severe core melt with penetration of the RPV.

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  88. IF it was damaged and spent fuel pool level lost, RAD levels would be sky high.

    I linked to the cabinet minister saying that the concrete building collapsed (many other sources are saying the same thing):

    http://www.reuters.com/article/2011/03/12/japan-quake-reactor-idAFTKZ00680620110312

    He is also quoted as saying the radiation levels did not increase post-explosion (in other links, I think they are supposed to have decreased). And the Mark I containment’s spent fuel pool is on the top level.

    So how to reconcile this?

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  89. Sorry, evacuation of 40,000 people from a 10km exclusion zone is ITSELF a very serious accident and confirmatin that authorities believe there to be a credible risk of much worse.

    I stand by my statement. I judge it would currently be rated INES Level 4: Accident with local consequences or lower on the international nuclear event scale.

    A serious accident is Level 6 or 7. As such, my statement was quantitatively precise and correct.

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  90. @em1ss, In order to understand the Fukushima accident, you have to understand the basics of a Mark I BWR containment. A Mark I containment has two containments, the primary containment and the secondary containment (which, I, incorrectly, but commonly refer to as the drywell). The primary containment surrounds the reactor pressure vessel (RPV) and has a torus shaped supression pool. The secondary containment (also known as reactor building) surrounds the primary containment and contains the ECCS and spent fuel pools, from what I can tell from the news reports, this is what has failed in the explosion and it most likely damaged the torus as well.

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  91. This is very dangerous, because the supression pool ventilation network, which directly connects to the primary containment, which means the primary containment is essentially connected to the atmosphere!

    I understood that Edano’s statement ruled this out? They concluded there was no break in containment, because there was no increase in radioactivity outside… (right?)

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  92. Pingback: La fusión del núcleo del reactor atómico de Fukushima: lo que nunca querríamos haber vivido, en directo | Las mejores web en español

  93. James, my first SRO certification was on a Mark 1 containment. I fully understand the Torus and the Drywell Primary Containment. The Torus is similar to the Suppression pool used on later GE BWR designs.

    The safety issue is total size for a Mark 1 containment and ultimately heat removal capability. Hence why most Mark 1 plants are relatively small in thermal capacity.

    Secondary Containment is as you said the Reactor Building and it’s associated ventilation boundaries. Should anything leak out of primary containment it would be monitored via Reactor Building ventilation prior to release from the stack or isolated from release upon detection.

    Also best I can tell, this plant does not have RCIC, it has an isolation condenser similar to the one I am familiar with. It likely only had dedicated HPCI, LPCI and Core Spray Systems. Auto Depressurization System (ADS) via SRVs to permit LPCI and Core Spray injection.

    It is indeterminate if all the ECCS systems failed except ADS due to the Station Blackout caused by Emergency Diesels failing.

    ADS is the system that would have required batteries to allow cycling of SRVs to lower vessel pressure. Battery capacity is typically 4 hours to support ADS and Emergency Diesel Starts.

    All I have read in print was vessel makeup was by injecting fire water post Station Blackout.

    I still ask for a link that states the primary containment, essentially the Drywell and/or the Torus for a Mark 1 containment failed.

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  94. With regards to venting from the torus with failed fuel, you have to over ride the ventilation isolation interlocks for abnormal radiation levels. But venting to lower pressure protects the contaiment from failing and releasing forever. Best I can tell that is what they were doing, which is text book.

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  95. @em1ss: I was not trying to assert that the primary containment failed, but that the secondary containmnet failed (I idiotically referred to the secondary containment as a drywell, which, I know refers to the primary containment) and this, due to the design of the mark I BWR with the torus being outside of the drywell, could have damaged the torus, resulting in leakage from the primary containment ( primary containment -> damaged torus -> leak). I am just speculating that the torus is damaged, but the japanese gov seems not willing to confirm or deny that even the primary containmnet is intact, all they are willing to to say is that the RPV is still intact. sorry about the confusion

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  96. Barry, correct classificiation according to the INES scale is not the point.

    The point is that if you evacuate 40,000 people from a 10km radius that is correctly perceived to mean that a serious accident HAS happened and that the authorities believe there is a credible risk that something much worse COULD happen.

    If no significant numbers of people had to be evacuated the “usual suspects” would of course still make the usual noise with the usual effect.

    But because 40,000 people DID have to be evacuated, the repercussions ARE much more serious. (I am deliberately not saying WILL or MIGHT be but ARE).

    People don’t want industries that require disruptive evacuations. They WILL demand still greater regulaton and safety. So any strategy of getting LCOE for nuclear below coal by easing regulation and “excessive” safety just got considerably less plausible.

    Granted immediate tasks countering alarmist rumours are more pressing. But you will need to reflect on this later.

    Even if everyone hear unanimously agrees its INES level 4 or less serious and even if that becomes the official conclusion, the consequences of having to evacuate 40,000 people ARE that achieving an immediate rollout becomes that much harder and proposing massive R&D that includes nuclear as well as other technologies and provides for nuclear research and training institutes and plants becomes that much more attractive an alternative strategy.

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  97. James link that they have the portable diesels connected and to what?

    I am not sure they brought anything bigger than to keep the batteries charged yet. That would be a small towable dc diesel like some US plants have purchased for Station Blackout to extend ADS availability. A diesel to run ECCS type pumps would be quite large.

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  98. I can give you the TEPCO press release which argues that external AC power is availble.

    http://www.tepco.co.jp/en/press/corp-com/release/11031221-e.html

    Multiple news reports have said that they brought in some sort of emergency power generation, presumably diesels. Your right about the power requirement regarding ECCS (quite significant) and also wouldn’t it be a little complicated to connect the external power up to the emergency power trains? They seem to be cooling mainly thorugh the isolation condenser and Make-up Water Condensate System, which is relatively low volume right? All of this seems to indicate they still have a high rx pressure…

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  99. I suspect the evacuation may be tied to the failed Fuel Cladding, Reactor Building (Secondary Containment), Spent Fuel Pool exposure to the atmosphere, and/or dual units struggling with cooling due to Emergency Diesel failures. There is always some judgement call with Protective Action Recommendations (evacuation distance and shelter distance), one you can’t win either way after the fact.

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  100. The question is, if they have external power availbe, why didnt they run the reactor building vent fans as well as vent the reactor building to the stack to reduce H2 concentration (I dont think Mark I have H2 ingnitors, only Mark III do) before they blew the whole building, as well as run LPCI and core spray.

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  101. News releases are usually colored a bit as we all know. One plant I know has little hand carried honda ac generators and inverters to keep the SRVs available by damage control procedures. Along with a slightly larger towable to charge the batteries and air start systems to allow emergency diesel restarts.

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  102. BBC reports an explosion.

    NHK:
    Explosion heard at quake-hit reactor

    The Nuclear and Industrial Safety Agency is trying to confirm a report that an explosion occurred at a nuclear power station in quake-hit Fukushima Prefecture.

    The agency said on Saturday that a person at the Fukushima Number One nuclear station reported that an explosion was heard and smoke was seen near one of the reactors at around 4PM.

    The power station operator Tokyo Electric Power Company told the agency that 4 people were injured.

    Video of the reactor in question shows the outer wall of the building that houses the reactor has disappeared.

    Prefectural authorities say the power company informed them that the ceiling of the building collapsed after an explosion.

    http://www3.nhk.or.jp/daily/english/12_50.html

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  103. James Krellenstein,

    The TEPCO press release you linked was for Fukushima Daini. The reactor in question is at Fukushima Daiichi. Nothing on the TEPCO website, as far as I can see, indicates that external power is available at Daiichi.

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  104. I mean it has been over a day, you don’t think they got the diesels up and running? What about the condensate make up system, doesnt that require safety AC? Second of all, if they are truly in a station blackout, and already have core damage, what is the plan to get the core covered?

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  105. I don’t think they had power to run the ventilation fans. Hence why I question the reports about diesels brought in.

    They would likely need a 3-5 MW diesel to support ECCS pump loads and ventilation, just one train of ECCS too typically. We’re talking a big diesel and big cable tie ins via the ECCS off site tranformer sources likely. Railroad car sized. The rail system is a mess now too.

    Too soon to be available even now let alone prior to the explosion by my judgement. Better chance of restoring off site power, but don’t know the scope of that damage either.

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  106. “officials say the explosion was not a nuclear explosion” –NPR. John Hamilton being interviewed: “very strong blast … looked like the building that houses the reactor … as workers were trying to add water … that can cause hydrogen …”
    “nothing they did seemed to be enough to keep the core under control …. extended the evacuation …. out to 12 miles away”

    “the containment structure … did not go in the explosion and the radioactive material is inside that…. they are going to flood the core with seawater … they are also going to put in boric acid ….”

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  107. The core was being kept covered by fire water by last report I read. Standard text book severe accident response. Which could be a diesel fire pump. Diesel pumps are easier to aquire than the size Diesel Generator required to use installed ECCS or non ECCS pumps.

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  108. Just asking, does everyone here understand that Hydrogen is a normal byproduct of fission in a BWR, even through decay heat…. It slows with the reactor shutdown, but doesn’t go away for awhile. Adding water doesn’t produce hydrogen alone….the fission in the core does.

    I always read news reports with some skepticism. For example, “It wasn’t a fire. It was a spontaneous exothermic reaction resulting in heat and smoke.” That was a classic news release I saw once.

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  109. That was early this morning, the fire water makeup. They were switching straight to Sea Water later this morning, which would be the fire back up source I would presume. Meaning they likely used their available clean fire source or would and want to keep some available in case another fire breaks out on site.

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  110. Old steel with 40 years of neutron embrittlement has to be a current concern, the hope would be I think that the temperature change is slow enough that there’s not a shock that fractures anything important. The reason for adding borate would have to be to anticipate a possible collapse of the fuel to the bottom of the structure producing a hot spot that would be less well flooded with water, the ‘China Syndrome’ configuration.

    Above are my amateur guesses both.

    Much appreciate the people who’ve posted with real experience and knowledge and pointers and pictures.

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  111. Based on reports of Radiation releases and Rad Levels… I’d bet on yes. But that could change quick. As time passes they gain time to respond to failures, decay heat lowers. Until now they have been floating at the boiling point in the core it seems.

    If they get sea water injection to the core that will cool them down and establish a time to boil should injection be lost. Pump water in, relieve it to the Torus until containment flood up is achieved. This will cool the core and the Torus.

    This unit despite indicated minor fuel damage is likely off line forever. Just based on age and the Reactor Building damage alone.

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  112. They had only decay heat removal via SRVs available to the Torus, until the Torus became to hot to suppress the steam. All that Hydrogen produced is in containment and the Torus. The MSIVs were closed.

    They had to vent the Torus to prevent over pressurization and primary containment failure. Yes Zirc Water could contribute, but the gaseous releases while venting don’t support that amount of clad damage yet.

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  113. Stepping back, the cautionary lesson here ought to be associated with the warnings about (1) sea level rise over the next 50-100 years raising the baseline against which a storm surge/tsunami will rise, worst case; and (2) a big solar flare taking down the electrical grid across a continent or worldwide, again at least the worst case from the 1800s telegraph era (do we have paleo evidence for anything worse than that?)

    It sounds like these two Japanese plants were prepared for one or two plants at a time to need emergency cooling, with quick return of external AC power.

    We have a small example of what would happen if the whole grid went down across a larger area because of a major flare (where it might take a year or more to replace transformers).

    Sounds to me like it’s time to recommend collaborative designs to go with (Gen4) fission plants — large solar collector fields, and pumped water, hot salt heat, or compressed air geological power storage; put together in a way that each such design site would have redundant power available while all went well, and _still_ have a large stable power supply onsite for the worst case loss-of-grid accident.

    And that whole system needs to be built well, well above the anticipated worst case height of a tsunami on top of a high tide during a storm surge after a century of sea level rise.

    Barry, it’s time to throttle the economists and get the public health and safety design people involved in building the next generation of power systems.

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  114. The US grid is in complete neglect with deregulation in some areas and not in others. Stability is the worst I’ve ever seen it and that should be addressed post this event for sure.

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  115. > water as a moderator

    The worry would be a collapse to create a ‘bowl of hot stuff’ at the bottom of the building in an area that’s already flooded with water. Or rather, worst case would be that then breaking through to the water table — the whole plant is on flat ground and is at sea level, the ground under must be saturated with water by now just from the pumping.

    Yes, once an area heats up enough to boil, the steam won’t slow neutrons down, so you’d get worst case something that would heat, then cool, then heat — as long as water could get back into the material.

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  116. http://www.world-nuclear-news.org/RS_Battle_to_stabilise_earthquake_reactors_1203111.html

    “authorities are preparing to distribute tablets of non-radioactive potassium-iodide. This is quickly taken up by the body and its presence prevents the take-up of iodine should people be exposed to it.

    Seawater injection
    The injection of seawater into the building started at 8.20pm and this is planned to be followed by addition of boric acid, which is used to inhibit nuclear reactions. However, Tepco reported at 10.15pm that a new tsunami warning has caused this to be suspended temporarily….”
    ——

    CDC on potassium iodide:
    http://www.bt.cdc.gov/radiation/ki.asp

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  117. Actually James it is important. If it went to the stack via Reactor Building Ventilation it would have been diluted had the fans been running. Ie. non explosive concentration, despite the high concentration being vented.

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  118. Folks the 1,015 microsievert was a reading taken right after the explosion around 3:30 pm in Japan.

    Consequent measurements taken after showed a significant drops of radiation level. Also that the pressure within the Canister was deceasing on it’s own as well.

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  119. If I had to take a guess on the cause of the explosion, I’ll take a leakage of the hydrogen turbine coolant (used to cool the generator, same as with any coal plant) as my guess – not hydrogen from within the reactor coolant.

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  120. Now that I think about it and reflect on the Company media posts. What’s between the Containment and the atmosphere? The Reactor Building walls. The media spin doctors could call that the space between primary containment and concrete walls (Rx Building walls ie secondary containment).

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  121. This is not good news.

    http://www3.nhk.or.jp/daily/english/12_57.html

    “… Fukushima Prefecture says 3 patients at a hospital near the damaged nuclear power plant have been exposed to radiation.

    The hospital is located in Futaba Town about 3 kilometers north of the Fukushima Number One Nuclear Power Plant. It is within the designated evacuation area of 10 kilometers around the quake-damaged plant.

    The 3 were chosen randomly for radiation testing from 90 patients and staff who were waiting for airlift by helicopter at a nearby high school on Saturday afternoon. The prefectural government says the 3 need decontamination to remove the radioactivity. They have not shown any reaction or physical symptoms of the radioactivity yet.

    Sunday, March 13, 2011 00:58 +0900 (JST)”

    Like

  122. Luke that would have destroyed the turbine building, which appears to be intact. Not blown the walls off the Reactor Building. I was hoping that too early on until the pictures were clearer.

    Like

  123. Or maybe the area or part of the building ventilation that blew was actually isolated from the main vent path, but leaking slightly. That would explain why the torus vent path is reported as still in tact.

    Like

  124. Gregory Meyerson

    I got that news directly from a press conference off of NHK tv.

    Yukio Edano said they were taking regular measurements of radioactivity starting at the time of the explosion. I’ve got an earlier post describing the the amounts and at what time. He also stated the the pressure inside the reactor was decreasing as well. This is also where I heard the use of sea water.

    Here’s a link to the press conference that I saw which has a basic description in English:

    http://www3.nhk.or.jp/daily/english/12_56.html

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  125. Pingback: Microsiervos | Linkeando

  126. May I ask some more stupid questions (in relatively layman terms)?

    Although the fission of uranium has stopped, thermal energy from the decay of the materials in the fuel rods must be removed by circulating coolant water through the reactor. The presence of cesium and iodine compounds in the steam released from the containment building shows that the fuel rods have failed (either split or melted) and any coolant water sent into the reactor will absorb radioactive material.

    1. Is it true that the coolant water circulation loop at this plant has only one eventual heat sink, the circulation of ocean water to cool the coolant water? From the absence of cooling towers, I am assuming that this is the case.

    2. Is it true that the presence of radioactive materials in the steam vented from the containment building means that both the fuel rods have failed contaminating the coolant water system, AND that the earthquake has created leaks in the coolant water circulation system, such that radioactive material and hydrogen accumulated in the containment building, and this accounts for vent of radioactive materials?

    3. The explosion seems to have been caused by hydrogen buildup in the containment building and systems. If the coolant water circulation is continued, as it must to remove decay heat from the reactor, does this mean there will continue to be leakage of the radioactive coolant water?

    4. The presence of significant radiation at the plant perimeter, and the fact that three people randomly selected from an evacuation zone showed high levels of radioactive exposure, means that radioactive material is dispersing through the environment around the plant. If the coolant water circulation in the plant continues, as it must to remove decay heat, won’t the leakage of radioactive material continue, give the failure of the containment systems?

    5. Does the fact that the operators are now planning to flood the reactor with seawater, mean that seawater will be circulated through the reactor? But any seawater circulated through the reactor will need to be discharged to effectively remove heat from the reactor?

    6. So instead of circulating coolant water and suffering radioactive releases from leaks in the coolant water and containment system, they have elected to circulate large amounts of seawater through the reactor, which will be contaminated with radioactive material and the radioactive seawater will be dumped in the ocean? So instead of vent releases to the air, authorities are electing to try and minimize vent releases by circulating seawater and contaminating the ocean instead?

    7. Can the seawater circulated in this manner be contaminated with plutonium?

    I would appreciate any answers from the nuclear experts on this thread.

    Like

  127. I have family and friends in Japan and am finding it very frustrating to find news and information from credible sources in English. I came across this site and it has helped enormously – THANK YOU! I have seen so many conflicting reports on TV and on the internet – from meltdown is imminent to risk is low….what do you think of “expert” interviews like this

    Like

  128. I’m assuming that they’re talking about something like spraying seawater into the containment, to cool it, bring pressure down, and to help scrub out any gaseous radioactive contamination if it’s present.

    I don’t think they would actually put seawater into the reactor coolant system – that’s nuts. It seems completely pointless and unnecessary, and it will basically completely write off the reactor.

    Like

  129. Ok, it appears from this account, that they aren’t circulating seawater through the reactor, but using seawater to deliver boric acid into the reactor containment, however the wording in this statement seems vague.

    Sea water used for cooling down the reactor

    The Tokyo Electric Power Company is using sea water as an emergency coolant in its quake-damaged reactor at Fukushima Number One Power Plant.

    The massive earthquake on Friday caused a breakdown of cooling systems that could cause temperatures in the reactor to rise to uncontrollable levels.

    Chief Cabinet Secretary Yukio Edano disclosed on Saturday that the company is pouring sea water into the containment vessel of the reactor. Sea water is readily available as the plant is close to the sea.

    Edano said the company is mixing boric acid with the water to help absorb neutrons to slow nuclear fission.

    Edano added that government’s Nuclear and Industrial Safety Agency has endorsed the procedure.

    Self-Defense Force troops, who are actually in charge of the cooling process, are using pump trucks and other methods to inject the sea water. They say the work started on Saturday evening will be completed on early Sunday.

    Like

  130. > seawater to deliver boric acid into the reactor
    > containment

    Guessing — would the logic here be to surround the actual reactor vessel, to fill the concrete building shell with boric acid solution? So if the reactor vessel steel doesn’t shatter, it’d cool down, and if the steel does shatter and the fuel structure collapses into the bottom of the building, it’d be falling into the boric acid solution.

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  131. I have a question about containment domes.

    Was the thing that gave way at the daichhi nuclear plant a containment dome or is it as barry suggested that the CD is internal?

    second, if the answer is the former, is this the sort of dome that jets cannot penetrate, as in the you tube videos?

    Like

  132. Hydrogen from zirconium oxidation at high temperatures vents to outer building; explodes. They announced prior to explosion they’d be doing some venting to reduce pressure. That’s my guess.

    Like

  133. Tepco seems way behind, their latest press release still says:

    “Indication from monitoring posts installed at the site boundary did not show any difference from ordinary level. No radiation impact to the external environment has been confirmed. We will continue to monitor in detail the possibility of radioactive material being discharged from exhaust stack or discharge canal.”

    Like

  134. Last night I recall a problem with opening vents — one vent was too radioactive to get a worker to it. Has that been updated anywhere? I wondered if this is why they had hydrogen building up–perhaps they weren’t able to vent enough of it out fast enough? But I haven’t seen mention of that problem at all today.

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  135. It seems that this is a classical example of cascading failure.

    The nuclear engineers on this site are quick to point out the ‘strengths’ of each defensive layer. However, the reality of catastrophic situations is that they tend to reveal the ‘weakness’ of each layer.

    ‘Defense in depth’ is predicated on the idea that the probability of each layer being simultaneously or near simultaneously defeated is improbable. However, as most seiges of castles showed, and most cascading failure events as well, there is a relatively high probability that a chaotic, uncontrolled situation will defeat each layer in turn – given enough time.

    The nuclear engineers will now jump on the time element and say that the reactor going cold means ‘time is on the nuclear operators side’. However, that logic only applies for a near steady state scenario.

    Disaster is simply a combination of factors waiting to align. Over time, a chaotic system will test the system repeatedly – the permutations multiply and eventually nature finds the key to complete failure. Simply put, all man-made systems are eventually destroyed by nature because chaos is kinda hard to model against.

    To relate how mistaken the nuclear engineers are, it’s obvious that this earthquake was not a ‘10,000’ year event – it just makes the top 10 list of the last century. The reactors structure may have been able to withstand the forces of an even larger earthquake, but the reactor ‘system’ couldn’t withstand the external failures caused by the earthquake.

    If everything went ‘according to plan’, this reactor should still be operating. Now the question is: how good are the plans for dealing with the failure of the nuclear operations plan?

    By the way, I like nuclear more than coal…but renewables more than all.

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  136. according to the nisa documents linked by hank, radiation release increased in a 5-6 hour period from .7 to 5.1 at main gate and .7 to 2.7 (in microsieverts) at observation post.

    that’s a lot lower than 1015.

    I don’t know what these numbers relation is supposed to be.

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  137. It’s not clear how many plants are in trouble now. Is there a map showing Fukushima 1 and 2? Separate evacuation zones declared? I’m seeing only fragmentary stuff in translation:

    Evacuation area around Fukushima No.2 expanded
    http://www.nhk.or.jp/daily/english/politics.xml

    NHK WORLD English
    … The prefectural government of Fukushima has … expanded the evacuation area around Fukushima Number 1 Power Station from … kilometer radius around the Number 2 Power Station. …
    http://www.nhk.or.jp/daily/english/society.html

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  138. Luke – Where we are today, I wouldn’t put any money on a restart of Fukushima Daiichi reactor 1. If filling the reactor vessel with seawater is needed to stabilize the decay heat, that’s what they should do.

    Like

  139. http://www.newscientist.com/blogs/shortsharpscience/2011/03/massive-explosion-rips-through.html

    Yukio Edano, Japan’s Chief Cabinet Secretary, said the cause of the explosion was a mixture of hydrogen, from steam escaping the core, and oxygen from the surrounding air.

    He added that the pressure vessel was unaffected and the incident would not be a cause for a large amount of radiation to leak.

    Although the concrete cladding disintegrated in a spectacular fashion, Grimston said that the fact that the metal frame of the building was left intact suggests that the explosion was not as violent as it looked.

    Because the plant went into operation in 1971 and is due for decommissioning, the decision was taken by Tepco to flood it with seawater containing boric acid to kill the nuclear reaction.

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  140. Current latest NISA release with the ‘microsieverts’ measurements is:
    http://www.nisa.meti.go.jp/english/files/en20110312-4.pdf
    —–
    From 04:00, March 12 by the measurement of radioactive materials in the surrounding area of the power station using monitoring cars. (As of 09:40, March12)
    It was confirmed that radioactivity was increased compared to the one at 04:00, March 12.

    MP6 (near the main gate) 0.07microSv/h ->5.1 micro Sv/h (04:00, March12->09:10, March 12)

    MP8 (observation platform) 0.07microSv/h ->2.9 micro Sv/h (04:00, March 12->09:40, March 12)

    NOTE where the decimal points are; I’m _guessing_ that 0.07microSv/h is the baseline (anyone know?)

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  141. OK, I understand that given the reactor’s age they will probably write it off.

    “Because the plant went into operation in 1971 and is due for decommissioning, the decision was taken by Tepco to flood it with seawater containing boric acid to kill the nuclear reaction.”

    This boric acid business doesn’t make any sense. The control rods are all in, the reactor is fully subcritical. Why are we talking about emergency addition of boric acid? There shouldn’t be any kind of criticality issue at all, from my understanding.

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  142. @Hank Roberts

    The English news releases are going to be slow to update. Tokyo Electric, the Prime Minister, and Chief Cabinet Secretary Yukio Edano have all had numerous press conferences on national tv in Japan.

    The info is out there but there’s only fragments of what they said in English. Kind of sad, you think CNN would have someone watching NHK to translate what was said.

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  143. Luke, you can get a whole lot of heat out of the fuel rods for four days or so after a proper shutdown. If the cooling water system has failed (did the ECCS ever get used, anyone know??) then the fuel rod assembly is going to continue to get worse. If the control rods fall out — if the structure falls apart — the fuel rods can end up in a random pile along with the rest of the structure. That could put hot stuff together in a way that lets the heat increase enough to melt the steel. So they want the boric acid solution all around to catch the pieces that could fall through the bottom of the steel containment.

    That’s an amateur guess only. Wait for someone who knows better for a better answer.

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  144. I’m still not clear if the boric acid is going into the concrete building _around_ the steel bottle, or if they’re actually pumping it into the bottle so it floods the reactor core. Anyone got a pointer to better info? Those are very different tactics.

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  145. NYT:

    “The blast, apparently caused by a sharp buildup of pressure or of hydrogen when the reactor’s cooling system failed after the quake, destroyed the concrete structure surrounding the reactor but did not collapse the critical steel container inside, they said. They said that raised the chances they could continue cooling the core, and prevent the release of large amounts of radioactive material and avoid a full core meltdown at the plant.

    Tokyo Electric Power … plans to fill the reactor with seawater to cool it down and reduce pressure. The process would take five to 10 hours, Mr. Edano said, expressing confidence that the operation could “prevent criticality.”

    The company also said its workers also added boric acid to the containment vessel on Saturday night to poison the nuclear chain reaction.
    ——–
    http://www.nytimes.com/2011/03/13/world/asia/13nuclear.html?_r=1&hp=&adxnnl=1&adxnnlx=1299960040-FXxZ1eYct1HY/+40l2dlLg

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  146. Oops. Here’s another radiation figure — this in “rem”
    1 rem=0.01 Sv

    “Fukushima – Home Page Promo – March 2011UPDATE AS OF 12:30 P.M. EST, SATURDAY, MARCH 12:
    … Tokyo Electric Power Co., reported that radiation levels next to the Unit 1 machine building had increased from 0.007 rem per hour to .67 rem per hour.”

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  147. This helps explain — the boric acid apparently is being pumped both into the steel bottle-reactor core and also around it.

    http://www.npr.org/blogs/thetwo-way/2011/03/12/134486565/at-crippled-japanese-nuclear-plant-last-ditch-effort-to-prevent-meltdown?ft=1&f=1001

    Linda Wertheimer speaks with NPR’s Jon Hamilton

    “On Weekend Edition, Jon told host Linda Wertheimer that the plan to flood the core with seawater and boric acid may be unprecedented and will effectively destroy the power plant. If the plan fails and the core does meltdown, Jon said the only thing left to do will be to “seal it up with concrete. You sort of entomb it.”

    And it would be the containment structure that would be entombed — hopefully with any radioactive material still inside. In theory, NPR’s Science Desk tells us, if there was a meltdown that destroyed the steel and ceramic around the fuel rods the containment structure would still be able to prevent any material from being released into the environment…. At Three Mile Island in Pennsylvania, the containment structure prevented a disaster when part of the core melted during a 1979 accident.

    The situation likely won’t be resolved quickly. According to Japan’s Kyodo News:

    “The top government spokesman said Tokyo Electric Power has begun operations to fill the reactor with sea water and pour in boric acid to prevent an occurrence of criticality, noting it may take several hours to inject water into the reactor. In addition, it will take about 10 days to fill the container with sea water, he said.”

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  148. Discussion about what happens when a core starts to melt make comparisons to Three Mile Island — which was a different design, with a large containment building — domed top — around the whole reactor bottle and associated equipment.

    “Because adequate cooling was not available, the nuclear fuel overheated to the point at which the zirconium cladding (the long metal tubes which hold the nuclear fuel pellets) ruptured and the fuel pellets began to melt. It was later found that about one-half of the core melted during the early stages of the accident. Although the TMI-2 plant suffered a severe core meltdown, the most dangerous kind of nuclear power accident, it did not produce the worst-case consequences that reactor experts had long feared. In a worst-case accident, the melting of nuclear fuel would lead to a breach of the walls of the containment building and release massive quantities of radiation to the environment. But this did not occur as a result of the three Mile Island accident.”

    It may help to compare the TMI building to the pictures above in this thread of the BWR-3 (Fukushima-1 is a BWR-3 according to the references given earlier).

    http://www.nrc.gov/reading-rm/doc-collections/fact-sheets/3mile-isle.html
    http://www.nrc.gov/reading-rm/doc-collections/fact-sheets/3mile-isle.html#tmiview

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  149. This may be reassuring. While the diagrams above show a “spent fuel pool” located immediately next to the top of the reactor bottle — that’s not longterm storage, it’s a handling point for refueling operations.

    Here is a description from late 2010 of the site and an assessment of its spent fuel storage — shows the building (though not where the building is on the site). Spent fuel is in dry casks, sealed and air-cooled. I don’t know what if anything would have been in the pool at the top of the reactor building and haven’t seen any pictures since the explosion to know what that situation is. But most of the spent fuel should have been well away from that. What the tsunami did to the storage is an open question though. How much water did hit the site?

    ——

    Integrity Inspection of Dry Storage Casks and Spent Fuels… Storage Status of Spent Fuel at Fukushima-Daiichi NPS. ➢ Approx. 700 spent fuel assemblies are generated every year. ⇨Stored in spent fuel pools / dry …
    http://criepi.denken.or.jp/result/event/seminar/2010/issf/…/6-1_powerpoint.pdf

    This may be the same document:
    http://www-ns.iaea.org/downloads/rw/conferences/spentfuel2010/sessions/session-ten-b/session-10b-japan-1.ppt.

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  150. > last ditch

    > last ditch

    Seemed appropriate to me.

    “Last ditch” is an idiom in US English, often used describing football for example. It comes from trench warfare–World War 1 or even earlier: the last line holding back the enemy advance, well inside the perimeter that was thought defensible.

    They’re using “last ditch” for an action beyond the planned “layered defense in depth” steps. Those were reversible and could have recovered the plant in condition it could be salvaged. Once the building exploded, that was pretty much not going to happen.

    (One of those steps was the Emergency Core Cooling System–did that even get tried before the building explosion? I would guess from the video, which showed big chunks being thrown a long way through the air, that they may have lost the pipes and valves outside the steel bottle then.)

    Can you suggest another step after filling the plant with sea water and boron? That’s been reported as not something that was one of their layered plan steps.

    If that works, the bottle stays intact, the whole area cools off below boiling, the radiation decays away, they pump the contaminated water through filters and demineralizers to concentrate the waste, and they eventually clean it up.

    If that fails — if they don’t get the core cold and it ends up breaching the bottle — what’s to do except entombment of the whole site?

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  151. Damn.

    Sat Mar 12, 2011 4:17pm EST

    (Reuters) – A quake-hit Japanese nuclear plant reeling from an explosion at one of its reactors has also lost its emergency cooling system at another reactor, Japan’s nuclear power safety agency said on Sunday.

    The emergency cooling system is no longer functioning at the No.3 reactor at Tokyo Electric Power Co’s Fukushima Daiichi nuclear power facility, requiring the facility to urgently secure a means to supply water to the reactor, an official of the Japan Nuclear and Industrial Safety Agency told a news conference.

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  152. Another idiom:
    http://abcnews.go.com/International/japan-fukushima-nuclear-power-plant-explosion-workers-injured-radiation/story?id=13120888

    “Flooding the containment vessel with sea water mixed with boron instead of fresh water is an unusual measure, according to Robert Alvarez, a senior scholar at the Institute for Policy Studies, who described it as a “Hail Mary pass” but a necessary step to keep the reactor core covered and the containment vessel cool.”
    —————
    http://www3.nhk.or.jp/daily/english/12_34.html
    updated at 18:16 UTC, Mar. 12

    A nuclear emergency has been declared at Fukushima No.2 nuclear plant …. This follows Friday’s emergency declaration for Fukushima No.1 nuclear plant ….
    … the pressure control system is not functioning at the plant’s 3 reactors….

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  153. Pingback: The Japanese nuclear reactors « SeekerBlog

  154. Firstly, far more megawatts of renewable power could be generated per pound/dollar spent on nuclear, Consider, for example, the new epr reactor, Olkiluoto 3, in Finland. Already costing over 6 billion euros, it is set to provide 1600 Mwatts of electricity.Compare that with about 3.5 million for a 2 Mwatt wind turbine. 1600 Mwatts would then cost about 3 billion euros,and even before you take into account the economies of scale that result from upscaling from a single 2Mwatt turbine. That’s also before you factor in the cost of decommissioning and waste management.

    We urgenrly need to stop wasting our finite capital on fission energy.

    Secondly, although nuclear power is less emissive than fossil fuels, it still requires huge fossil fueled machinery to extract it, and then further energy is required to transport it to where it is needed. As a means of combatting carbon emissions, it’s only the second worst of many evils. Nuclear power stations themselves too require a huge amount of resources to build and operate.

    Thirdly, uranium itself is finite. To replace fossil fuels with nuclear would bring forward “peak uranium” to a point in the very near future.

    I’ve heard it argued, by James Lovelock and others, that Nuclear power is essential to provide a reliable energy source while a transition to renewable sources takes place, but nuclear power plants take over a decade to plan and construct and activate. We need cuts in emission NOW, not 15 years down the line. Also, see my first point. If the same capacity can be constructed quicker, greener and for a fraction of the cost going for renewables now, what on earth is the point of going nuclear?

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  155. hey paul:

    You’re new here. Glad you showed up. I think all of your arguments are incorrect but don’t have the energy to go into details. The section at BNC on renewable energy is excellent and you should spend some time reading all the articles, along with much of the response. Everyone of your points is addressed in great detail.

    It would be nice if what you said was true; but I don’t think it is.

    Meanwhile, I’m feeling depressed. I have spent several years studying the energy/ecology crises as a fairly intelligent non expert.

    And even though I think we have to go with gen three and four nuclear, I’m at the moment less than optimistic.

    Maybe it’ll look different in the morning.

    btw, I thought the point way above thread about Defense in depth not handling multiple problems at once is a good point. Course, with passive safety, we wouldn’t be in this pickle.

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  156. ///Course, with passive safety, we wouldn’t be in this pickle.////
    Yeah, agreed.

    Right now I’m hoping we can invent the super-cheap battery to make renewables an option, because I’m losing confidence that we can overcome the ‘nukes aren’t safe’ argument.

    Last night the world watched a nuclear housing container building explode. It’s NOT a good look! Unless they can comprehensively show that the core is safe and this is not another Chernobyl, we’re done. Where’s Peter Lang with his “Older, cheaper, Nastier Nukes to save a few bucks!” now when these older cheaper nukes have blown up in his face?

    We either need to show that nothing ‘really bad’ happened here, or that the new technologies WILL NOT do this.

    And if we can’t… then I don’t have much hope that we’re going to get through global warming and peak oil with our civilisation intact.

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  157. Paul
    Sure (if you say so)you can build 1600Mwatts of wind power but you fail to mention the capacity factor. What happens when the wind isn’t blowing? You need back-up power, probably gas-fired(fossil fuel) to ensure continuity of supply. How much will that cost?
    As to peak uranium, it is a myth when you consider that new IFR reactors can burn nearly 100% of the fuel and also use once through uranium(waste) as a fuel source. – then there is uranium from sea water.
    Obviously you need to educate yourself and this blog gives you all the information you need if you are genuinely interested in the facts and not the hyperbole. Read the posts on renewables and nuclear and learn something useful.

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  158. EN
    You are overreacting. According to reports it was the building next to the nuclear housing building exploded and the walls of that building collapsed as a result. The containment vessel is untouched. The IAEA have rated the occurence as a Level 4 incident (Barry predicted that several hours ago) which is less than Three Mile Island, which we all know was not a problem.

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  159. Quote: “Consider, for example, the new epr reactor, Olkiluoto 3, in Finland. Already costing over 6 billion euros, it is set to provide 1600 Mwatts of electricity.Compare that with about 3.5 million for a 2 Mwatt wind turbine. 1600 Mwatts would then cost about 3 billion euros,and even before you take into account the economies of scale that result from upscaling from a single 2Mwatt turbine. That’s also before you factor in the cost of decommissioning and waste management.”

    Sounds good until you understand that 2Mwatts is only 17% of the time whereas the nuclear plants works 93% of the time.

    When you starting match the Mwatt output and the capacity factor you have to have thousands of networked windmill across vast regions using thousands of miles of transmission lines that requires more energy input that you get from the life time of the windmill. And you kills birds and endangered bats.

    The only “renewables” worth talking about are large hydroelectric (destroyed in earthquake) and geothermal (indirect nuclear). Greenies oppose those along with nukes because they work.

    The greens only believe systems that deliver a negative rate of energy return on investment.

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  160. “Unless they can comprehensively show that the core is safe and this is not another Chernobyl, we’re done. ”

    Either that is propaganda or you’re just caving into it. Coal has killed and polluted and will kill and pollute far, far more than nuclear has and ever will. (see
    http://frankwarner.typepad.com/free_frank_warner/2006/01/us_coal_mining_.html). Correct me if I’m wrong, but wind power disrupts the environment and is unreliable, AKA not cost-effective. Solar is ridiculously expensive and requires a lot of water.

    One 40 year old reactor melts down thanks to a double natural disaster on one of the most active spots along the “Ring of Fire”, and now “we’re done”? Are we supposed to go back to horse and buggies, or what??

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  161. I think EN has a very serious point, and should be taken seriously. Ms Perps I think you missed his point.

    The point I think EN is making is that even though the consequences of this accident are not extreme, the public will not see it that way. Media hysteria and all that.

    EN I really agree with your last point. God, if your up there, you may have screwed our last serious hope of saving the planet.

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  162. I don’t see the ramifications of this as damaging at all to nuclear power’s prospects. First, it won’t make a jot of difference to the plans of China, India, South Korea etc. Second, a level-headed analysis after the event will underscore the point that even in the most extreme of situations, with a well beyond design basis event, a 40-year old reactor held up to the most trying circumstances nature could throw at it. It will also point to further improvements that can be made to BWR management and emergency response. Finally, it will provide a great conversation starter for talking intelligently to people about nuclear safety. Remember folks, a large-scale future expansion of nuclear power is inevitable in the long run, and vital in the medium-term if we are to move away from our 80% reliance of fossil fuels today. No amount of hype or FUD can change that basic reality.

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  163. http://www.nytimes.com/2011/03/13/world/asia/13nuclear.html?hp

    “TOKYO — Japanese officials took the extraordinary step on Saturday of flooding a crippled nuclear reactor with seawater in a last-ditch effort to avoid a nuclear meltdown ….
    … The Japanese Nuclear and Industrial safety agency said as many as 160 people may have been exposed to radiation around the plant, and Japanese news media said three workers at the facility were suffering from full-on radiation sickness.

    … Olli Heinonen, the former chief inspector for the I.A.E.A., and now a visiting scholar at Harvard, said on Saturday…. “Now, every hour they gain in keeping the reactor cooling down is crucial,” he said.

    But he was also concerned about the presence of spent nuclear fuel in a pool inside the same reactor building. The pool, too, needs to remain full of water, to suppress gamma radiation and prevent the old fuel from melting. If the spent fuel is also exposed — and so far there are only sketchy reports about the condition of that building — it could also pose a significant risk to the workers trying to prevent a meltdown in the core….”

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  164. BBC reports say:

    #
    2318: US nuclear experts warn that pumping sea water to cool a quake-hit Japanese nuclear reactor is an “act of desperation” that may foreshadow a Chernobyl-like disaster, AFP reports. “The situation has become desperate enough that they apparently don’t have the capability to deliver fresh water or plain water to cool the reactor and stabilise it, and now, in an act of desperation, are having to resort to diverting and using sea water,” said Robert Alvarez, who works on nuclear disarmament at the Institute for Policy Studies.

    #
    2326: The Japanese cabinet secretary, Yukio Edano, has been speaking on state TV. He said the third reactor at the Fukushima No. I plant was in danger but attempts were under way for a controlled release of air.

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  165. Hank
    “three workers at the facility were suffering from full-on radiation sickness.”

    Let’s get a bit of perspective here- over 100 people have been injured /killed in the oil and gas fires. Not forgetting the hundreds/thousands killed by the quake/tsunami. 10,000 missing from one town which has been wiped out.

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  166. PaulK2

    “The situation has become desperate enough that they apparently don’t have the capability to deliver fresh water or plain water to cool the reactor and stabilise it, and now, in an act of desperation, are having to resort to diverting and using sea water,” said Robert Alvarez, WHO WORKS ON NUCLEAR DISARMAMENT at the Institute for Policy Studies.”

    Well, given his job and therefore his bias, he would say that wouldn’t he.

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  167. “Japan’s nuclear safety agency reported an emergency at a second reactor Sunday in the same complex … Nuclear and Industrial Safety Agency told the Associated Press early Sunday that the cooling system had malfunctioned at Unit 3 of the Fukushima Daiichi nuclear plant. Officials said they were informed of the emergency by Tokyo Electric …”
    http://www.latimes.com/news/nationworld/world/la-fgw-japan-quake-reactor-20110313,0,3933329.story

    Like

  168. Ms Perps; No, it was the reactor building that had an explosion, but the Mark I BWRs have a crane area superstructure on top of the main concrete building. That area was wrecked; whether and how far the damage extends into the rest of the building is not clear, but that structure has clearly not been destroyed or even reduced significantly. The spent fuel pool for example should be fine, and the characteristics of the damage suggest to me that the explosion was actually in the crane area rather than coming up from deeper in the building.

    Like

  169. Pingback: Top Posts — WordPress.com

  170. Barry,
    I agree that those countries making evidence-based decisions (China, India, S Korea, …) will continue unabated.
    I fear though that the massive negative publicity of this event in Japan will be reinforced in perpetuity by the anti-nuke crowd, thus making nukes of any kind un-touchable, politically, in EU, North America, Aus, etc.
    Unfortunately the anti-nuke crowd will do everything they can to taint by association newer designs – Gen IV, MSR, LFTR, etc.. A massive set-back.

    Like

  171. Update here:
    http://www.world-nuclear-news.org/RS_Battle_to_stabilise_earthquake_reactors_1203111.html
    The ‘naked steel frame’ visible in the post-explosion pictures appears to be the framework shown here at the top: http://www.world-nuclear-news.org/uploadedImages/wnn/Images/bwr%20cutaway.jpg

    “Later television shots showed a naked steel frame remaining at the top of the reactor building.”

    Same image earlier here: http://i.imgur.com/CckjP.jpg — so it’s clearer now that the concrete structure around the reactor is still in place — it’s this metal framework holding thin walls and roof that blew off, leaving the bare grid showing.

    That grid held the walls and roof around the space above the top of the reactor bottle — the space around the crane and work area used to move fuel rods, and above the pool used to hold used fuel rods which is to the side of the reactor bottle.

    Like

  172. Los Angeles Times
    March 12, 2011, 3:52 p.m.
    http://www.latimes.com/news/nationworld/world/la-fgw-japan-quake-meltdown-20110312,0,2889362.story

    “… a government official told CNN Sunday morning Japan time.

    “There is a possibility, we see the possibility of a meltdown,” said Toshihiro Bannai, director of the international affairs office of Japan’s Nuclear and Industrial Safety, in a telephone interview with CNN from the agency’s Tokyo headquarters. “At this point, we have still not confirmed that there is an actual meltdown, but there is a possibility.”

    Bannai said engineers have been unable to get close enough to the reactor’s core to know what’s going on, and that he based his conclusion on radioactive cesium and iodine measured in the air near the plant Saturday night….”

    Like

  173. “Already costing over 6 billion euros, it is set to provide 1600 Mwatts of electricity.Compare that with about 3.5 million for a 2 Mwatt wind turbine. 1600 Mwatts would then cost about 3 billion euros,and even before you take into account the economies of scale that result from upscaling from a single 2Mwatt turbine.”

    According to your own numbers Olkiluoto-3 is a steal compared to wind, even though it’s a first-of-a-kind plant in a nation with limited experience.

    With an industry typical 80-90% capacity factor the nuclear plant generates 1.3-1.4 GW on average; that’s $4.2-4.8 per watt of average power.

    1600 MW of wind turbines with an industry typical 20-30% capacity factor generate 0.3-0.5 GW of average power. That’s $6-9/W of average power, not counting the cost of building powerlines to remote areas that are only used some of the time(due to the abyssmal capacity factor of wind) and not counting the difficulties of integrating a non-dispatchable power source into the grid(storage is keeps being suggested, but what happens in the real world tends to be sucking on a big fat gas pipe courtesy of Russia).

    Like

  174. http://www.reuters.com/article/2011/03/12/us-japan-quake-tepco-radiation-idUSTRE72B3PJ20110312
    Sat Mar 12, 2011 5:51pm EST

    (Reuters) – Tokyo Electric Power Co (9501.T) has begun preparation to release radioactive steam from a second reactor at its quake-struck Fukushima Daiichi nuclear power facility, a spokesman said on Sunday.

    The TEPCO spokesman said preparation work for the release began at 7:30 a.m. (5:30 p.m. EST).

    An official from Japan’s nuclear safety watchdog said earlier on Sunday that it had received a report from Japan’s largest power producer at 5:10 a.m. that the facility’s No. 3 reactor had completely lost its emergency cooling function.

    —–
    On the No. 1 plant:
    http://www.reuters.com/article/2011/03/12/us-japan-quake-iaea-idUSTRE72B3C520110312

    Sat Mar 12, 2011 4:33pm EST

    (Reuters) – Japan told the U.N. atomic watchdog there was an initial increase in radioactivity around a quake-hit nuclear plant on Saturday but levels “have been observed to lessen in recent hours,” the Vienna-based agency said.

    The International Atomic Energy Agency (IAEA) said it had also been informed by Japanese authorities that Saturday’s explosion at the Fukushima Daiichi plant occurred outside the primary containment vessel, not inside.

    “The plant operator, Tokyo Electric Power Company (TEPCO), has confirmed that the integrity of the primary containment vessel remains intact,” it said in a statement that is likely to be seen as positive for efforts to contain the damage.

    The government insisted radiation levels were low, saying the blast had not affected the reactor core container.

    …. Workers pumped sea water into the reactor to cool it.

    “As a countermeasure to limit damage to the reactor core, TEPCO proposed that sea water mixed with boron be injected into the primary containment vessel,” the IAEA said.

    “This measure was approved by Japan’s Nuclear and Industrial Safety Agency (NISA) and the injection procedure began at 20:20 local Japan time.”

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  175. Not a Nuclear Expert, but knowledgable and will try to answer your questions.

    1. Is it true that the coolant water circulation loop at this plant has only one eventual heat sink, the circulation of ocean water to cool the coolant water?

    Yes – There is no cooling tower so the normal heat sink is ocean. But there also is some type of pond that is shared on site by layouts I have seen. This pond may just be water storage though for normal emergency injection, discharge dilution or firewater.

    2. Is it true that the presence of radioactive materials in the steam vented from the containment building means that both the fuel rods have failed contaminating the coolant water system, AND that the earthquake has created leaks in the coolant water circulation system, such that radioactive material and hydrogen accumulated in the containment building, and this accounts for vent of radioactive materials?

    The Cesnium and Iodine detected are normal fission product gases which can’t normally be detected of significance without zirconium fuel cladding damage too some degree (cracks, pinholes etc). Cesnium and Iodine levels can also be used to predict level of fuel failure (actual pellets inside clad). They would be present to some level even without fuel pellet failure and released at some level upon clad leakage. The fuel rods are designed for some normal fission product gas buildup inside the fuel rod cladding over fuel life without overpressurizing the fuel rod.

    First of all the in Mark 1 Containment design the Primary Containment consists of a steel lined drywell and the attached steel lined Torus (suppression chamber). The fission product gases (Cesnium and Iodine) and hydrogen are released from the vessel to the containment during opening of reactor Safety Relief Valves (SRVs) to control reactor pressure. The Steam from the SRVs is directed to the Torus (suppression chamber) below water level and suppressed (quenched) for as long as the Torus temperature stayed below boiling. Discharging the steam below water level also scrubs some of the fission product gasses.

    Reaching 100 C Torus temperature was significant in that it meant Torus suppression capability was ultimately lost to suppress the steam from the reactor SRVs. This means cooling of the reactor was being lost via this method.

    From that point on any reliefs opened would rapidly pressurize the Torus (containment) requiring containment venting to the release stack to lower Torus pressure and prevent Primary Containment failure due to overpressurization.

    Primary Containment failure would mean continuous release from Primary Containment to Secondary Containment (the Reactor Building). As we know the Reactor Building is not entact, so there is no secondary containment boundary left.

    There is no indication of an actual vessel or primary coolant system leak yet reported. The fact that the reactor was repressurizing in between SRV openings is a good gross indicator of that. Vessel level was only being lost due to steam release via SRVs.

    The fission product gas levels measured during release indicate at most only minor fuel pellet damage and some definite fuel clad damage. Remember there is fission product gas buildup inside the fuel rod clad do to normal operation.

    3. The explosion seems to have been caused by hydrogen buildup in the containment building and systems. If the coolant water circulation is continued, as it must to remove decay heat from the reactor, does this mean there will continue to be leakage of the radioactive coolant water?

    The explosion in the Secondary Contaiment (Reactor Building) was due to Hydrogen. It is unclear how this occurred during attempts to pump water into the vessel as reported.

    As explained above, there is no report of or indication of a primary system coolant leak or leak in the reactor vessel pressure boundary.

    Once the containment is flooded heat transfer is from the core to the Salt Water and then radiant through the primary containment steel liner to what’s left of the Reactor Building. You can also feed and bleed, add and remove water to increase cooling. But the volume of water once the containment is full should suffice as decay heat declines over time.

    They are injecting salt water via containment spray system which will quench any steam in the containment air space during injection, rapidly lowering containment pressure until all the steam is gone.

    This minimizes necessary contaiment venting. But some venting will still be required to permit the volume of saltwater being injected to displace the containment air space.

    4. The presence of significant radiation at the plant perimeter, and the fact that three people randomly selected from an evacuation zone showed high levels of radioactive exposure, means that radioactive material is dispersing through the environment around the plant. If the coolant water circulation in the plant continues, as it must to remove decay heat, won’t the leakage of radioactive material continue, give the failure of the containment systems?

    The only containment failures based on reports are fuel clad leakage and reactor building secondary containment. Only reported releases are fission product gases due to containment venting operations.
    The reported radiaton levels are not that high to indicate fuel failure.

    Loss of walls in the reactor building would reduce shielding which would increase rad levels external above normal. Flooding the containment will increase shielding via water from the source the reactor core. Water is better than concrete at shielding.

    5. Does the fact that the operators are now planning to flood the reactor with seawater, mean that seawater will be circulated through the reactor? But any seawater circulated through the reactor will need to be discharged to effectively remove heat from the reactor?

    See the explaination above of why you flood containment for heat removal. Passing through the core would cool the core faster if you kept an SRV open. But this method would also move alot more radioactive particulate contamination from the core into the containment. See above why containment spray is being used to lower containment pressure too.

    6. So instead of circulating coolant water and suffering radioactive releases from leaks in the coolant water and containment system, they have elected to circulate large amounts of seawater through the reactor, which will be contaminated with radioactive material and the radioactive seawater will be dumped in the ocean? So instead of vent releases to the air, authorities are electing to try and minimize vent releases by circulating seawater and contaminating the ocean instead?

    No coolant is being circulated back to the ocean using the methods as reported.

    7. Can the seawater circulated in this manner be contaminated with plutonium?

    If there is fuel pellet damage and clad damage there could be some fission product plutonium detectable in the coolant. Plutonium is a fission product of uranium and always present in spent fuel. As already stated no coolant (salt water) is being circulated back to the environment.

    I would appreciate any answers from the nuclear experts on this thread.

    Like

  176. I am not an expert, just reading, but I think this
    > As we know the Reactor Building is not entact,
    >so there is no secondary containment boundary left.

    is wrong. Look at the pictures e.g. in Barry’s post above at https://bravenewclimate.com/2011/03/12/japan-nuclear-earthquake/#comment-113954

    The primary containment is a steel bottle around the core — the tall cylinder. That sits inside a concrete secondary containment (like a short fat bowling pin shape) that’s cast concrete — part of the building concrete but sealed and capped.

    Those are not pressure vessels, not meant to hold in a high pressure (this is a boiling water reactor not a pressurized water reactor). They did have a vent system that would have led vented material through a filter system.

    That apparently failed and the gas was apparently vented into the building, maybe because of the problem reported last night of one of two valves being inaccessible because of radiation levels (anyone hear more on that?).

    The rest of the building (including the thin top walls and roof that blew off) is not a containment vessel in this design, and not sealed — it was just closed enough to hold in enough hydrogen gas to have an explosion, but that blew up and outward stripping away the walls and roof leaving the steel frame exposed.

    Both of those as far as we know are intact and being flooded now with sea water and borate. Both of those would have been protected from building up too much pressure inside, by releasing steam/air pressure and hydrogen/oxygen gas by opening valves.

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  177. I haven’t seen mention of circulating the sea water/boron solution, just pumping it in (taking up to ten days to fill the outside containment). It will take maybe three or four days for the fuel rods to cool down to where there’s less urgency. My guess — just a guess — is the water/boron is intended to be left in place and topped up for a while rather than circulated — with some boiling away, and some release of steam and radiation from the vents.

    If there were a working cooling pump system and a working cooling pond as a way of cooling water on the loop pumped through the reactor, they’d be using that and removing heat that way — and that’s not happening.

    Like

  178. They are not out of the woods and home yet with this unit, but following the industry established severe accident procedures seems to be working. Effectively protecting the public. This event is way beyond design basis as previosly discussed.

    The real concern now is the spent fuel pool which is likely exposed due to the Reactor building wall failures.

    The actual spent fuel pool walls are typically steel lined and significantly greater thickness concrete than the external building walls so structurally it is likely ok. The reactor building typically has blow out panels for a steam leak. Failure of actual walls indicates the magnitude of the hydrogen explosion beyond the analyzed pressurization from a steam leak.

    As long as they can maintain level in the pool no increase in rad levels should occur. If they lose level though, rad levels will rise dramatically on site and at the site boundary. Keep an eye out for significant rad level changes or actual reports of spent fuel pool status.

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  179. Hank, the primary containment in a Mark 1 design is the torus and drywell. Secondary containment is the reactor building and it’s ventilation systems. Read the whole thread this has been previously established.

    As far as normal ECCS pumping methods, they are in a station blackout and all electrical ECCS systems except for ADS (using SRVs) are unavailable.

    Like

  180. Hank also regarding spent fuel. It is normally first removed from the vessel and stored in the spent fuel pool for several years of decay. Then it is loaded into casks and placed into dry fuel storage vaults on a pad.

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  181. Using seawater is not a “hail mary pass”, to use the American football term, but it certainly is the absolutely last choice.

    Nimitz-class A4W reactors have that capability, for use IF water cannot be circulated through the loop(s) and heat removed through the steam generators AND reserve feedwater has run out AND potable water is running out AND the core still needs to be covered, THEN blanking plates can be removed AND large couplings installed AND valves opened to allow firemain water (seawater) to flow through the Rx and into the RX compartment.

    Afterwards, you remove the fuel and then replace everything that was touched by seawater, because the corrosion issues both inside and outside the primary piping. It would be much less expensive to simply take the whole mess and put it on a barge to Hanford where the rest of the decommissioned submarine RX compartments sit and then rebuild the plant, than it would be to clean and try to inspect everything.

    Like

  182. Hi Ms Perps and any (like Matt) that seem to think I’m an anti-nuclear troll, Huw’s got my back. Yes, I remain convinced that nukes are the only way to solve global warming and peak oil with today’s technology. I’m not talking about my own personal reaction but the *public* reaction.

    They saw a ‘nuclear building’ explode. Add Addinal’s description of geiger counters sniffing babies, and that will settle it for many. They won’t care about Level 4 distinctions. People are often just too busy to look into these details. Most people I meet are not ‘bloggers’ and don’t really care about energy and sustainability issues. They’re sucking down beer as they watch the sport, and worrying how much this carbon tax is going to cost them. I get the impression that maybe 20% or 30% of the people I meet actually believe climate change is all a greenie power grab, and the tax confirms it. Their views on energy issues are decided for them by carefully crafted 10 word sound-bytes from anti-nuke activists. Or, as I was saying earlier, from spectacular visual events like this Japanese ‘nuclear thing exploding!’

    It all depends on how the media handle it from here. The media LOVE a disaster, and hate Barry’s approach of level headed analysis. Boo, hiss, boring! It doesn’t make for a 10 word sound byte or snappy headline! Careful analysis might one day get explored on a show like Catalyst, but will Channel 7 or 9 or 10 run it? I don’t think so.

    As Addinall said:
    ///I am afraid the media and the usual culprits from the Dark Greens are not letting go of this.///

    What kind of ‘analysis’ do we see of these matters on Neighbours or Home and Away? Sadly, that’s the kind of media penetration we’re after.

    So unless we see headlines like “INDESTRUCTIBLE Japanese Core proves nuclear safety” I think the media ‘fallout’ will settle the case for many.

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  183. “KEVIN RUDD has called for urgent briefings from Japan on the threat posed by an explosion at a nuclear plant and said Australia had offered Tokyo atomic expertise.”

    Now THAT was genuinely FUNNY!

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  184. > containment

    You’re right, em1ss, thank you.

    Here’s a picture identifying Fukushima Daiichi 1 as you describe: http://i1107.photobucket.com/albums/h384/reactor1/BoilingWaterReactorDesign_3.jpg

    Larger: http://i1107.photobucket.com/albums/h384/reactor1/BoilingWaterReactorDesign_3.jpg

    from http://www.nei.org/howitworks/boiling-water-reactor-design

    So in these terms, the secondary containment blew off. But in this PWR-2 design, the building doesn’t really “contain” –it’s not air tight in this old design.

    In a newer design the secondary containment would be a sealed building, often with the typical dome, giving an actual second layer of real containment.

    I was thinking of the reactor pressure vessel as a “containment” — it’s not, although it is a closed container.

    > spent fuel
    When used rods are first removed, I think they are temporarily put in the water tank container in the reactor building itself, up near the top of the reactor under the crane; I and others had earlier confused with the “spent fuel pool” but is only a brief holding area (no idea if it had any fuel rods in it as of this time–some bloggers out there were speculating that fuel rods stored there would be exposed after the explosion)

    The “spent fuel pool” is pictured in the powerpoint file I linked above (session-10b-japan-1.ppt), described as “A large-scale pool 12m x 29m x 11m(depth) fuels more than 19-month
    cooling”; used to cool rods down; and after that there’s the dry cask storage.

    Like

  185. The pool basin Spent Nuclear Fuel inventory for the Vermont Yankee BWR Mark I reactor which went on line in 1969 and it is about 690 MTHM containing ~75.6 Mega Ci, predominantly Cs-137 and Sr. 90.

    Like

  186. Ah, there was a better description in the doc I linked long ago, only yesterday: “the reactor building, which doubles as a secondary containment….”

    http://www.ansn-jp.org/jneslibrary/npp2.pdf

    “The primary containment vessel encloses the reactor pressure vessel, other primary components and piping. … The containment is a reinforced concrete containment vessel (RCCV) with a leak tight steel lining. The containment is surrounded by the reactor building, which doubles as a secondary containment. A negative pressure is maintained in the reactor building to direct any radioactive release from the containment to a gas treatment system. The reactor building and the containment are integrated to improve the seismic response of the building and the containment are integrated to improve the seismic response of the building without additional increase in the size and load bearing capability of the walls….”

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  187. Er, this one that’s got the worst problems is a “BWR-3” design — from the same npp2.pdf file, showing the timeline of development:

    “7×7 type fuel development (high power density and long fuel rod) Fukushima I-1 (BWR-3)”

    Like

  188. I don’t see a mention of this morning’s ‘Sunrise’ TV program which seemed to give a balanced view. A couple of journos talked about the role of containment vessels and the problems with coal as an alternative. They interviewed anti-establishment economics academic Steve Keen who predicted the 2008 GFC when others failed to see it coming. Keen argued the case for thorium reactors.

    When the dust settles it will be interesting to compare nuclear harm with that of natural forces, several injuries vs thousands of deaths. Not good enough apparently.

    Like

  189. Argh: “http://discussions.latimes.com/20/lanews/la-sci-japan-quake-sixth-reactor-20110313/10” says “Fukushima No. 1, also known as Fukushima Daiichi, which was disabled by an explosion overnight that destroyed the building housing the reactor and the backup cooling system.”

    Way wrong. Very confused. I got a comment in pointing to

    http://www.world-nuclear-news.org/RS_Battle_to_stabilise_earthquake_reactors_1203111.html

    which has pictures making clear that the reactor building just lost its top, but look how easily confusion arises about what’s what

    Quoting from the World Nuclear News page:

    “Later television shots showed a naked steel frame remaining at the top of the reactor building. The external building structure does not act as the containment, which is an airtight engineered boundary within….”
    and
    “Chief cabinet secretary Yukio Edano appeared on television to clarify that the explosion had damaged the walls and roof of the reactor building but had not compromised the containment.”

    —–
    Bottom line — there’s no “secondary containment” now and no negative air pressure because the building’s lost its top. Might as well refer to “the containment” if you’re pointing people to descriptions to clarify what’s there.

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  190. http://www.tepco.co.jp/en/press/corp-com/release/11031304-e.html

    * High Pressure Coolant Injection System of Unit 3 automatically stopped. We endeavored to restart the Reactor Core Isolation Cooling System but failed. Also, we could not confirm the water inflow of Emergency Core Cooling System. … reported … at 5:58AM, Mar 13.
    In order to fully secure safety, we operated the vent valve to reduce the
    pressure of the reactor containment vessels (partial release of air
    containing radioactive materials) and completed the procedure at 8:41AM,
    Mar 13,

    Like

  191. Unit 1 is a GE BWR 3 with Mark 1 Containment. Major concern with a Mark 1 Containment is primary containment volume size and heat removal capacity via the torus. Secondary Containment remains the same in all BWR 3-6 designs as reactor building and it’s ventilation systems.

    Hence why they modified the Mark 1 Containment (Torus vs Suppression chamber) design to provide an over pressure vent capability directly from the Torus to the exhaust stack. That vent would contain fission product gas along with hydrogen. The vent is not connected to the Reactor Building (secondary Containment) ventilation system like newer BWR designs. Specifically it is not passed though the Standby Gas system first prior to release.

    Fission product barriers (protect the public) and estimated status based on reports are as follows:

    Fuel Pellet – indeterminate without specific coolant sample results but fission product gasses do not indicate gross fuel failure

    Fuel Clad – leakage is indicated due to Fission Product gasses present on venting. Any clad leakage would result in an increase though even if minor. Plants operate with leaking fuel rod clad on pins. They just suppress the power near that bundle.

    Reactor vessel and coolant system – no indication of failure yet reported.

    Primary Containment – Torus and Drywell – no indication of failure yet reported.

    Secondary Containment – Reactor Building and Ventilation systems – failed, walls gone due to hydrogen explosion. Why protecting the vessel and primary containment is so important.

    James and I chased this out to earlier today. I had an SRO cert on a similar design.

    I am concerned about the spent fuel pool status. They must keep it full, re-establish cooling and ventilation boundaries to the environment.

    This unit is likely finished operationally in my opinion. No return from direct seawater flooding of the containment.

    Like

  192. When the dust settles it will be interesting to compare nuclear harm with that of natural forces, several injuries vs thousands of deaths. Not good enough apparently.

    Quite. What has this earthquake taught us? That it’s much, much risker to choose to live next to the ocean than it is to live next to a nuclear power station. But I wonder whether that message will ever get through.

    Like

  193. Hi all,
    being in a career-change etc I don’t have time to read the ins and outs of every single media report on this, so I’m hoping Barry can summarise the gist of it all above when I come back to this topic in a week or so?

    Thanks all for your tireless work on this.

    Like

  194. Hank Roberts, on 13 March 2011 at 1:13 PM — The explosion seems to have just removed the sheet metal walls and roof of the penthouse. The concrete ‘secondary containment’ still ovbiously has walls; I doubt the concrete roof was damaged.

    Like

  195. Sidd, read the thread. Cesnium and Iodine are normal fission product gases that build up inside the fuel rod during operation. Any fuel clad leakage and they leak out. Operating SRVs (Safety Relief Valves) from the Reactor to the Torus puts them in Containment. Venting the Contaiment puts them out the stack to the atmosphere. Key is level observed, high gross fuel failure, low fuel clad leakage.

    Like

  196. Dave, not knowing the specific design but working off typical designs. The upper level of a BWR Reactor Building is not as hardened a concrete structure and would fail first on an internal explosion. The lower levels and ECCS rooms would be significantly hardened structurally.

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  197. Barry,
    In a battle between facts and emotions, emotions wins every time, and no matter what the facts are this is huge blow for the nuclear insutry here (and probably around the world). It might be safer to live near a nuclrar power station than the ocean, but people will now be even more scared of nuclear power.

    Like

  198. Hawkmon, yes, that is a real possibility, as least in some places. In which case, Australia will keep on burning coal and gas. Still, the global picture is of much bigger importance from a climate change mitigation perspective, and in that context, I see no significant alteration of the current trajectory.

    Like

  199. “In a battle between facts and emotions, emotions wins every time, and no matter what the facts are this is huge blow for the nuclear insutry here (and probably around the world). It might be safer to live near a nuclrar power station than the ocean, but people will now be even more scared of nuclear power.”

    The first thing we must understand is that what we are going to be told by statements made [ ad hom deleted]about what the public’s opinion on this matter is unlikely to be true. As I have pointed out here before, public opinion on nuclear energy is a function of public understanding, and it is not by any means uniform. We are going to see interviews, and sound bites by individuals identified as spokespersons for antinuclear groups with impressive sounding names, that will claim to be speaking for the majority. The reality is that these groups are most often little more than one or two people, a web page, and a P.O. box. They are however always available to the media for a quick statement, having cultivated reporters in their area to that end.

    I was stunned to see an absolute nobody from the Toronto area being tooted as an expert on nuclear matters, interviewed on the CBC National News. [ad hom deleted] as he called for the closure of all nuclear power stations in Canada in the wake of what was occurring in Japan. However I must say that I was pleased to also see that Discovery Canada sent a senior reporter to ask intelligent questions to the head of Bruce Power about the incident, and its implications for Canadian nuclear plants. This interview was broadcast on Daily Planet, Discovery’s nightly science news show.

    The lesson here is that we need to have our own spokespeople available to meet with the media on demand. Barry Brook has already positioned himself as the pronuclear go-to guy down there, but we need more credible people to take up this mantel in other countries.

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  200. Agreed DV8. I have done a dozen TV and radio interviews so far, and talked to various newspaper journos. Most, rather than being irked by my ‘just the facts’ approached, seemed quite relieved and probed me quite a bit with sensible questions. But my few short segments are being overwhelmed by the huge amount of hysteria being generated elsewhere, by both those who are being deliberately deceptive to suit their own ends, and those who just plain don’t know better. This is a tough battle ahead, for reality to trump hype and we need as many troops on the ground as possible. This is the time to sell the truth and push nuclear power forward as a rational solution, rather than be put on the back foot for another decade.

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  201. Sorry Barry, I definitely can’t help as a spokesman, company rules for now. Until I retire at least. 29 years of nuclear power operations, 2 years combined gas turbine and likely 5-7 to go.

    It will be a shame if the media turns this into a major disaster and sets back what needs to be done world wide to divorce ourselves from fossil fuels and their effects on the environment.

    Like

  202. great image hank, notice how the upper structure of the Reactor building is not hardened…. It clearly shows how a hydrogen explosion pressurization would result in the damage that occurred.

    Like

  203. When you see people refer to “Unit 3” and they’re confused — refer them to the press release and point out how similar the names are.

    Daiichi Unit 3 has a cooling system failure now;
    Daini Units 1-4 are venting to reduce pressure;
    Daini Unit 3 has a “hot stop” (whatever that is):

    http://www.tepco.co.jp/en/press/corp-com/release/11031304-e.html

    Fukushima Daiichi Nuclear Power Station:
    * High Pressure Coolant Injection System of Unit 3 automatically stopped. We endeavored to restart ….”

    Fukushima Daini Nuclear Power Station:
    Units 1 to 4: shutdown due to earthquake …
    * At present, we have decided to prepare implementing measures to reduce the pressure of the reactor containment vessel (partial discharge of air containing radioactive materials) in order to fully secure safety. These measures are considered to be implemented in Units 1, 2 and 3 ….
    * Unit 3 has been stopped and being “nuclear reactor cooling hot stop” at 12:15PM.

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  204. Thinking out loud here but Hydrogen is lighter than air, without power for Reactor Building Ventilation is it possible it collected in the upper levels near the refuel floor. Possibly they were trying to make up to the fuel pool by some type of temporaty injection and caused the explosion?

    Like

  205. Thanks for the great discussion everyone. It’s been a refreshing change from the rest of the news I’ve been reading online.

    I am curious what the worst case scenario is now? If the plant is off and cooling down, what is important about getting it to cool faster (e.g. pumping in sea water)? If it doesn’t cool down faster will something occur?

    I suppose I am just wondering if it is still possible (if everything went wrong from here on out) that we will end up with a large uninhabitable zone like Chernobyl?

    Like

  206. New update from World Nuclear News

    Venting at Fukushima Daiichi 3
    13 March 2011
    Operations to relieve pressure in the containment of Fukushima Daiichi 3 have taken place after the failure of a core coolant system.

    The news comes one day after the plant’s first reactor was effectively written off as a result of a hydrogen explosion and the move to inject seawater to make certain of cooling the reactor core. Two days ago were the earthquake and tsunami that have proven Japan’s worst ever natural disaster.

    Reactors 1, 2 and 3 were in operation at Tokyo Electric Power Company’s (Tepco’s) east coast power station when the earthquake struck. Three other reactors were already shut for inspection and all three operating units underwent automatic shutdown as expected. Because plant power and grid power were unavailable during the earthquake, diesel generators started automatically to supply power for decay heat removal.

    This situation continued for one hour until the plant was hit by the tsunami wave, which stopped the generators and left the plant in black-out conditions. The loss of power meant inevitable rises in temperature within the reactor system as well increases in pressure. Engineers fought for many hours to install mobile power units to replace the diesels and managed to stabilise conditions at units 2 and 3.

    However, there was not enough power to provide sufficient coolant to unit 1, which came under greater and greater strain from falling water levels and steady pressure rises. Tepco found it necessary yesterday to vent steam from the reactor containment. Next, the world saw a sharp hydrogen explosion destroy a portion of the reactor building roof. Prime minister Naoto Kan ordered the situation brought under control by the injection of seawater to the reactor vessel.

    Now Tepco has reported it has not been able to restart unit 3’s high pressure injection system after an automatic stop. This has left the reactor without sufficient coolant and obligated Tepco to notify government of an emergency situation.

    Preparations for potential pressure relief had already been underway for many hours. Noriyuki Shikata, director of global communications in the prime minister’s office, said the operation was expected to cool the containment, noting that “minute quantities of radioactive materials are released.” When this occurred at unit 1, the International Atomic Energy Agency said the emission would be filtered to retain radioactive materials within the containment.

    A ten kilometre evacuation order is in effect and some 200,000 people have been moved from their homes so far.

    Like

  207. Can anyone reconcile the IAEA page Barry posted just above: 0235 CET, 13 March 2011 — which now says: “CORRECTED An earlier version of this release incorrectly described pressure venting actions at Units 1, 2, and 4 at the Fukushima Daini nuclear power plant. Venting did not occur at these units.

    Japanese authorities have informed the IAEA that Units 1, 2, and 4 at the Fukushima Daini retain off-site power. Daini Unit 3 is in a safe, cold shutdown”

    compared to the press release from TEPCO (Mar 13,2011) quoted above, that’s contradictory on all those points?

    Like

  208. I don’t subscribe to addinall’s brand of [ad hom deleted]fatalism. Like abundant snowfall due to increased water vapor, this is a teaching moment. Please correct me if I’m wrong, but loss of coolant flow is not a serious problem with liquid sodium reactors, right? This is a very good opportunity to point out the advantages of FBR designs.

    Like

  209. I believe the problem with liquid sodium reactors is the activity issue with a loss of coolant accident. Sodium becomes highly activated when used as a coolant. At least that was the problem years ago.

    Like

  210. The problem with nukes seems to be the element of risk associated with it. The procedures established call for evacuation nearby. Currently though the risk of major environmental radiation pollution looks small – the practical effect of evacuating 200,000 people is HUGE.

    So, I’d never-ever want to live near a nuke plant – not because of radiation risk but because of evacuation risk. I already live in an earthquake zone – don’t want to tag along another risk.

    Like

  211. So government instructions are now mentioned in the latest TEPCO press release:

    Press Release (Mar 13,2011)
    Plant Status of Fukushima Daiichi Nuclear Power Station (as of 9am March 13th)

    All 6 units of Fukushima Daiichi Nuclear Power Station have been shut down.

    Unit 1 (Shut down)
    – Reactor has been shut down. However, the unit is under inspection due to the explosive sound and white smoke that was confirmed after the big quake occurred at 3:36PM.
    – We have been injecting sea water and boric acid which absorbs neutron into the reactor core.

    Unit 2(Shut down)
    – Reactor has been shut down and Reactor Core Isolation Cooling System has been injecting water to the reactor. Current reactor water level is lower than normal level, but the water level is steady. After fully securing safety, we are preparing to implement a measure to reduce the pressure of the reactor containment vessels under the instruction of the national government.

    Unit 3(Shut down)
    – Reactor has been shut down. However, High Pressure Core Injection System has been automatically shut down and water injection to the reactor is currently interrupted. We are examining alternative way to inject water.
    Also, following the instruction by the government and with fully securing safety, steps to lowering the pressure of reactor containment vessel has been taken. Spraying in order to lower pressure level within the reactor containment vessel has been cancelled….

    Like

  212. @Barry. Good video.

    Here is a REALLY BAD article that has just popped up on the Australian.
    http://www.theaustralian.com.au/more-bodies-found-as-japans-nuclear-crisis-worsens/story-fn84naht-1226020635376

    “JAPAN battled a feared meltdown of two reactors at a quake-hit nuclear plant, as the full horror of the disaster emerged on the ravaged northeast coast, with thousands feared dead.”

    Hmmmm. Implies causation. And the rest of the article never once tries to separate the two.

    Read it. It is quite ill-making.

    Like

  213. Hey everyone.

    I am just trying to get back up to date on what is going on. I found a pic on wikipedia, of the reactor building post:

    It looks like the only thing left is the top of the drywell. Does anyone have data on the intergrity of the spent fuel pools, it looks like everything at the reactorfueling level is gone, with only thing being the “socket” of the drywell

    Like

  214. NHK press conference

    Some interesting news about Reactor 3.

    1. They noticed water level had declined at 9:05 am so they lowered pressure the pressure and then started injecting water fresh water by use of a pump.

    2. Trouble occurred with the pump which required them to seawater.

    3. Injecting seawater was unstable in the beginning and the water level went lower and core was not fully cover by water and not fully cooled. But only for a short time.

    4. They soon stabilized it and brought the water level back up and the fuel core was completely covered.

    5. Part of the core within the reactor is deforming because of they were exposed outside water. But it wasn’t long enough for it to melt.

    6. Afterwards, huge amount of Hydrogen was generated because of the exposed fuel core. And they observed that to have collected in the upper part of the container.

    7. They believe the hydrogen that caused the explosion of reactor 1 was generated in the same manner. And collected in the upper part of the outer container as well.

    8. There wasn’t an explosion this time because the ventilation was functioning in reactor 3. Ventilation wasn’t working in reactor 1.

    9. Noted that when decision to use seawater was made, it’s also understood that the reactor would never be used again. The, seawater cools the reactor but it becomes extremely difficult to

    10. Sounds like they might use seawater on all of the reactors and close the entire plant.

    Like

  215. The cores in Reactors 1 and 3 both spend some time uncovered. And the core in reactor 1 is damaged but they don’t know the extent of it of the damage.

    Also at 1pm there was a radiation reading of 1557 microsvrs. It’s equivalent to 3 stomach xrays.

    It had dropped to 184 by 2pm and it’s current at 15.

    Like

  216. > It looks like the only thing left is the
    > top of the drywell.

    That’s well above the top of the fuel pool. Look earlier in this thread, at the picture:

    You can see the deep pool to the right of the reactor bottle. It’s way below the level that blew off. There’s a yellow bar across the top of it, and little rectangles at the bottom that must represent fuel, deep down under the water level.

    That’s assuming the water’s still there — but that would be hard to miss.

    Still, it’s a shame everyone’s guessing. I started writing yesterday in the older topic titled “An informed public is key to acceptance of nuclear energy” — hoping this would happen.

    It’s not happening very well. Way too much opportunity lost to actually explain how things work, how they’re put together, how these designs have changed since 40 years ago — and as Barry notes, how this 40-year-old design held together in a quake far above its design maximum.

    Crisis/opportunity.

    Like

  217. The fuel in the early stages of this incident and the 3 Mile Island incident does not melt. Early in the incident when the fuel is standing in the steam environment the temperature raises to 800 – 900 oC. At these temperatures, the protective black oxide film on the zircalloy tubing is lost by dissolving into the base metal. Then rapid corrosion with formation of thick white oxide flakes occurs and the tubes can crumble in minutes.
    pg 450 of http://books.google.com/books?id=gikdjXLfsVEC&pg=PA77&lpg=PA77&dq=zirconium+oxide+diffusion&source=bl&ots=Y2kLvpaTZc&sig=GfRnQCdgpcAMK39UrgWD2-V2fhU&hl=en&ei=22x8TaXBFMf4rAHd6oHMBQ&sa=X&oi=book_result&ct=result&resnum=10&sqi=2&ved=0CFIQ6AEwCQ#v=onepage&q=zirconium%20oxide%20diffusion&f=false

    The crumbled fuel drops to the bottom of the reactor vessel and you should have boric acid present as the configuration at the bottom of the reactor vessel is not controlled by geometry or even have control rod poison present. Late in the event, all the water will boil off around the mixed zirconium and uranium oxides and the hot oxides can proceed to melt with the adjoining steel vessel. Three Mile Island melted assorted metal devices that were through the oxide mass. It did not get to melting the pressure vessel before they quenched it.

    So now, we have stubs of zirc clad fuel standing up with zirc oxide and fuel pellets scattered around, between and below the stubs.

    Like

  218. The hydrogen accumulation is unit 3 is a concern, and must be relieved in a controlled manner. It’s too early to say much more on this. Overall, there are some salient lessons to be learned from this event for BWRs, and for the siting of backup generation in older reactor sites at sea level, which don’t include passive emergency cooling systems like Gen III designs.

    Like

  219. Pingback: Fukushima Nuclear Accident – a simple and accurate explanation « BraveNewClimate

  220. Pingback: The Japanese nuclear reactors: the geophysics « SeekerBlog

  221. New short summary from WNN:

    Earthquake impact on Fukushim Daiichi
    Reactors 1, 2 and 3 were in operation at Tokyo Electric Power Company’s (Tepco’s) east coast Fukushima Daiichi nuclear power plant when the earthquake struck. Three other reactors were already shut for inspection but all three operating units underwent automatic shutdown as expected. Because plant power and grid power were unavailable during the earthquake, diesel generators started automatically to supply power for decay heat removal.

    This situation continued for one hour until the plant was hit by the tsunami wave, which stopped the generators and left the plant in black-out conditions. The loss of power meant inevitable rises in temperature within the reactor system as well increases in pressure. Engineers fought for many hours to install mobile power units to replace the diesels and managed to stabilise conditions at units 2 and 3.

    However, there was not enough power to provide sufficient coolant to unit 1, which came under greater and greater strain from falling water levels and steady pressure rises. Tepco found it necessary yesterday to vent steam from the reactor containment. Next, the world saw a sharp hydrogen explosion destroy a portion of the reactor building roof. Prime minister Naoto Kan ordered the situation brought under control by the injection of seawater to the reactor vessel.

    Like

  222. Pingback: The Japanese nuclear reactors: Fukushima simplified « SeekerBlog

  223. Hallo all ,

    first let me thank for the excellent informations and the discussion in this thread.

    Also for the excellent aggregation of the event here

    https://bravenewclimate.com/2011/03/13/fukushima-simple-explanation/

    Would be great to spread this information.

    Even iam more on the contra side of actual nuclear power plants , here in germany we have a lot of old ones and final storage is also not solved. I prever to stay on the rational side (where ever this is ;) ).

    But this accident opens for me some questions ?

    How could it be that in a known tsunami area the back up power systems are not secured against?

    How could it be that in 3 out of 4 (at least i think so correct me if not so) suffer the same problems when there is always told that the systems are redundant (single point of failure ?) ?

    Why this importent information you people gave me , is not available on an offical side from tapco or the japanese government. (What imho is at least partly the reason for the reaction of media).

    So many greatings from germany and please forgive my horrible english.
    Thomas WAlter

    P.S I was the first time on this webpage but for shure not the last time

    Like

  224. Pingback: Depijama.com – Terremoto no Japão, vazamento nuclear e malucos de plantão atacam na internet

  225. Pingback: Why a MIT nuclear scientist is not so worry about Japans rectors | IAmA Cosmopolite AMA

  226. At the top of the building you see the refueling floor area. The crane for reactor dissassembly is shown in orange. The Spent Fuel Pool is below the refuel floor surface.

    The walls blown off the Reactor Building were essentially at refuel floor level and are not as robust as the balance of the building. The Spent Fuel Pool is a robust concrete structure that is steel lined.

    The water in the pool provides cooling and radiation shielding. Loss of water level in the Spent Fuel Pool would remove shielding and cause a significant increase in measured radiation levels on site and at the site boundary. That has not been reported as occurring yet.

    As long as water level can be maintained the pool will evaporate due to decay heat and remove heat from the spent fuel. Just have to maintain makeup water and level.

    How long the spent fuel has been in the pool since removal from the core determines decay heat load. Spent fuel is held for decay in the pool and when enough decay years have passed it is then loaded into dry fuel storage casks.

    The link below provides some US information on dry fuel storage. There are even U-Tube videos out there on it.

    http://www.nrc.gov/reading-rm/doc-collections/fact-sheets/dry-cask-storage.html

    Like

  227. “The risk of meltdown is extremely small, and the death toll from any such accident, even if it occurred, will be zero. There will be no breach of containment and no release of radioactivity beyond, at the very most, some venting of mildly radioactive steam to relieve pressure. Those spreading FUD at the moment will be the ones left with egg on their faces.
    I am happy to be quoted forever after on the above if I am wrong… but I won’t be.”

    this is a sincere question, but just as a casual observer trying to grasp the severity of the situation, i have to ask the following:

    given the latest updates on the matter, is it safe to assume that Barry’s assessment at the time has proven to be wrong? or at best not completely the most accurate?

    because if this is the case, every last ounce of optimism has just gone out the window for me. please say it ain’t so.

    Like

  228. Based on what we know so far, I’d say Barry is closer to the truth than much of the media reports. The reporters don’t understand what they are being told in a technical sense and often link the facts with death tolls from the quake etc for effect.

    Although things could change with another quake etc., the plant operators are responding pretty well considering the multiple concurrent events that occurred beyond the design basis of the plants. The evacuation zone has been conservative and the public exposure risk has been minimized. Lack of electric power has been the limiting factor in response to the events.

    The facts will all come out in the end, but the media won’t print it. It won’t be headline news. It will be shared throughout the nuclear industry in detail to capture any lessons learned.

    Like

  229. Update on Onagawa via BBC. It seems it is a Level 1 incident with the detection of some sort of radiation leak.

    brucerhee,

    I’d say that Barry’s assessment is still more or less correct. There does not seem to have been a major radiation release on the scale that poses a serious threat to public health.

    Like

  230. Pingback: » Why I am not worried about Japan’s nuclear reactors -

  231. If anything comes out of this it will likely be a change in emergency power sources. Hardened gas turbine units above ground that are duel fuel, gas or oil may be more prudent for units along the coastline. They don’t need cooling water.

    Like

  232. Quote “Also at 1pm there was a radiation reading of 1557 microsvrs. It’s equivalent to 3 stomach xrays.”

    Stomach xrays only last a matter of seconds so would it be correct to say it would be like a Stomach xray in which the doctor has forgotten to switch the machine off?

    Like

  233. Wow, nothing changed overnight? Pointer please if there is a current summary that’s not mentioned here? Just woke up and the radio sounds like much is new but it’s vague what if anything happened since 8 hours ago.

    Like

  234. Mr Goto said the reactors at the Fukushima-Daiichi nuclear plant were suffering pressure build-ups way beyond that for which they were designed. There was a severe risk of an explosion, with radioactive material being strewn over a very wide area – beyond the 20km evacuation zone set up by the authorities – he added. Mr Goto calculated that because Reactor No 3 at Fukushima-Daiichi – where pressure is rising and there is a risk of an explosion – used a type of fuel known as Mox, a mixture of plutonium oxide and uranium oxide, the radioactive fallout from any meltdown might be twice as bad.

    Like

  235. > why the diesel generators at Fukushima Daiichi
    > failed? … what was the mechanism?

    I posted this in the other thread yesterday:

    “CNN: “Crews had difficulty generating enough electricity to pump water into the facility ….

    Janie Eudy told CNN that her husband …. As he and others were planning to evacuate, at their managers’ orders, tsunami waves struck and washed buildings from the nearby town past the plant.”

    Like

  236. Satellite before and after the tsunami, including a closeup of the power plant (page down) — you can see how much got moved around right up to the four big square buildings housing the reactors. I’d guess the diesel generators must have been at ground level.

    http://www.abc.net.au/news/events/japan-quake-2011/beforeafter.htm

    This is also a reminder for us at a distance focusing on the power plants, that there’s far more devastation over a wide area.

    And it makes me think about what Seattle or Port Townsend or Vancouver or Portland will look like, after the next big subduction earthquake on the other side of the Pacific — which is also due by about now.

    Like

  237. Pingback: The nuclear bogeyman – Cloudy, turning to fud later

  238. Here’s an exerpt from the following link.

    Dale Klein, a former chairman of the NRC, said in an interview Saturday that using seawater to flood Fukushima Daiichi-1’s reactor core–and containment as a precautionary measure–is part of the plant’s emergency planning process. “If you’re near the end of your options, that’s one of them,” he said.

    Klein said such a procedure leads him to believe the condensate tank was broken or empty or the pipes leading to it were broken because it would have been used otherwise. The condensate tank is used to provide water to the emergency core cooling system.

    Klein, who chaired the NRC from July 2006 to May 2009, said future operation of the reactor “would be an economic decision that Tepco would have to make.” But he said that it was his guess that the company would consider building a new one instead. “It would be a major cleanup of contaminated components and water,” he said. The 460-MW unit 1 at Fukushima Daiichi (or Fukushima I) began commercial operation in 1971 and is the oldest and smallest of the Fukushima reactors.

    Klein said he would characterize the quake impact on Fukushima I-1 as “more like a Three Mile Island [but] with a lot more knowledge.” Operators at the Japanese unit “knew early on what they had to do, they just had trouble doing it.” he said.

    During the accident at the Three Mile Island-2 unit in Pennsylvania on March 28, 1979, operators mistakenly turned off the emergency core cooling system, which had automatically activated, because they erroneously believed the core was covered. The TMI-2 accident — in which there was a partial core meltdown — is considered the worst in US commercial nuclear power plant history but led to no deaths or injuries to plant workers, according to NRC.

    The workers at Fukushima I-1 set up emergency diesel generators to provide backup power for the cooling system, but they apparently ran for only a short time before being damaged by the tsunami, Klein said. Backup power could have been provided by batteries but that typically lasts only a few hours, and damage to the surrounding area appears to have cut off the option of bringing in additional emergency diesel generators, he said. “The earthquake had minimal impact; the tsunami had the impact,” Klein said.

    At early-afternoon EST Saturday, Klein said he believed there would be few fatalities due to the reactor itself, although he said the hydrogen explosion could have injured people in the plant. “I think this will be remembered for the fatalities from the quake and tsunami, not from the reactor,” he said.

    http://www.platts.com/weblog/oilblog/2011/03/13/whats_going_on.html

    Like

  239. em1ss, I’m talking about a loss of coolant *flow*, like in this situation with the failure of the pumps, not a loss of coolant. Yes, one drawback with liquid sodium is its reactivity with air (and water). That’s not the issue here. From what I’ve been reading about liquid metal reactor designs, even if the pumps are out and the coolant is not flowing, the thermal properties are such that overheating will not occur.

    Like

  240. Yes Sodium has that advantage thermally, but I still believe it has a higher activation rate, so overall radiation levels and activity from leaks is a concern….
    Much the reason the US navy abandoned it after the Seawolf early on as a moderator.

    Like

  241. How did the seemingly large amount of H2 get out of the reactor core (where it would have been generated by very high temperatures in reaction perhaps between zirconium alloy and water? Would this not suggest a severe breach of the core containment vessel and would the release of such quantities of gas from the core not have carried radiative contamination into the ensuing explosion?

    Like

  242. Samoht, this was discussed earlier in the thread. The Hydrogen got out of the vessel via Safety Relief Valve (SRVs)openings to the Torus (Suppression Chamber) to control Reactor Pressure and allow injection with low pressure sources. Decay heat was the enemy.

    Like

  243. > Samoht, on 14 March 2011 at 5:12 AM said:
    > How did the seemingly large amount of H2 get out

    Intentionally — through the valves opened to reduce pressure inside the containment. As of March 12:

    “… TEPCO said it managed to release pressure in the No. 1 reactor’s containment building.
    ….. The company was working to intentionally release radioactive vapor via escape valves … to lower the unusually high pressure inside.
    Workers tried to manually open valves to release vapor, but initially ran into trouble due to unexpectedly high radioactivity levels ….”
    http://www.yomiuri.co.jp/dy/national/20110312dy01.htm

    > Would this not suggest a severe breach

    No. An unusually large amount of gas is a sign of some damage, cracks on the waterproof outside cover of the fuel let water react with the hot metal.
    And
    No. Generating enough gas to raise the pressure inside — as did happen — means the gas is _staying_ inside the reactor.

    Like

  244. Pingback: Brave New Climate – Where are We in the Nuclear Event? « Climate Denial Crock of the Week

  245. Here’s a further annotated version of the now-familiar image, showing the spent fuel storage tank alongside the upper end of the reactor vessel (below the big crane):

    Hat tip to this post–a good summary:
    http://www.housepricecrash.co.uk/forum/index.php?showtopic=160968&view=findpost&p=2924962
    which begins
    “Right then. Who wants to know what actually happened? …. we need to look at the design of the reactor itself. I have been unable to find a decent diagram of the actual reactor at Fukushima, but here is a similar reactor, taken from the United States Nuclear Regulatory Comission’s Reactor Concepts Manual….”

    Like

  246. Night all, work tomorrow and lets pray for:

    * the people still suffering in Japan due to the Quake and the Tsunami.
    * the operators battling decay heat at the nuclear plants.
    * no more acts of nature to inflict more damage.

    Like

  247. Good info here:

    Insights into the Control of the Release of Iodine, Cesium, Strontium and other Fission Products in the Containment by Severe Accident …
    http://www.oecd-nea.org/nsd/docs/2000/csni-r2000-9.pdf

    Goes through the sequence of events and the temperatures and chemistry and type of damage and products expected to be coming off; describes boiling and pressurized water reactors.

    Index of docs from the site:
    http://www.oecd-nea.org/nsd/docs/indexcsni.html

    Like

  248. PS, from the csni-r2000-9 doc, this sounds like the approach being used for the damaged reactors in Japan:

    “There is thought now that especially for reactors with fuel having a low power density it may be possible to arrest accidents by simultaneously providing coolant to the core and by cooling the outside of the reactor vessel [S-14]. The radionuclide release consequences of prolonged retention of core debris in the reactor vessel have not received much attention.”

    Like

  249. And this:

    “A source of fission products to the reactor containment that is not often considered is release from a spent fuel pool located within the containment when pool cooling and residual heat removal cannot be maintained. This configuration of the spent fuel pool within the containment is found in the VVER-1000 reactors. Overheated fuel in the spent fuel pool can undergo gap release, release of radionuclides during fuel degradation and release as a result of molten fuel interactions with concrete. Physical and chemical phenomena associated with these stages of release are likely to be quite similar to releases usually considered in safety analyses except the ambient atmosphere will be air rather than steam [S-25]. No detailed analyses of severe fuel degradation and radionuclide release during accidents involving fuel in a spent fuel pool like that found in VVER-1000 reactors have been published.”

    and

    “The simplest categorisation is to treat the radionuclides that could be released from a nuclear power plant as a mixture of noble gases, gaseous iodine, cesium particulate and other particulate. Little can be done by way of accident management to attenuate the release of noble gases3 except to reduce the leakage from the reactor containment (See Chapter VII). Gaseous iodine release can be attenuated by trapping in water, adsorption on surfaces, chemical transformations and filtration (See Chapter VI). Most of the source term measures of accident management are focused on reducing the amounts of radioactive particulate that can be released from the reactor and discussions of the physical and chemical bases of these measures make up much of the rest of this document.

    fn3. There have been studies of methods to trap noble gases. In the main, absorption methods using zeolites or charcoal have been examined. Though the noble gases will absorb on these materials, it has proved challenging to engineer systems that will operate well under the range of conditions expected to arise in severe accidents.
    ________

    Like

  250. And again from the same document, this definition of “gap release” — which may be as far as these accidents go down the path toward ‘severe’ accidents, if the cooling by flooding seawater works.

    “Gap release
    Once an accident is initiated, coolant levels drop below the top of the active fuel. The cladding on the fuel ruptures and the gap inventory of radionuclides is released to the flow through the reactor coolant system. The gap release consists primarily of noble gases and the more volatile radionuclides such as cesium, iodine, and perhaps tellurium. Some finely fragmented fuel particles may also be released. Gap inventories have been the subject of debate for the last 20 years [S-6]. Some of the best experimental studies of gap release have been reported by Malinauskus and coworkers….”
    ___________

    The concern with the noble gases is that they don’t react chemically so are hard to capture, and the radioactive gas isotopes spread in the air for a while then decay later into solids.

    From a discussion about detecting products of undeground nuclear tests:
    http://www.idealist.ws/nokonuketest.php
    “… cesium 137 and strontium 90 tend to become distributed more widely than their fission byproduct peers – in a leak or vent – primarily because: a) their precursors gases are able to expand and rise rapidly while other nongaseous particles will have fallen to the ground and (b) these gases also escape the fate, of other fission byproducts, of (their or their decay products) being fused to surfaces or other particulates and thus gaining additional mass.

    Krypton and Xenon Gases

    Most radioactive products from any fission activity, including a nuclear blast, ‘began’ as a krypton or a xenon gas. All such gases are radioactive and xenons and kryptons can linger in the air for minutes, hours or years after deliberate or accidental venting from underground shafts.

    … some gases that escape during an underground explosion precipitate into ‘solid rain’. Krypton 90 is just one of dozens of radioactive noble gases that do transform in mid-air from gas to a solid.

    … In the 30 minutes from the time it is ‘born,’ Krypton-90 gas [decays] into a solid… ‘strontium 90,’….

    While many krypton and xenon gases are less radioactive than most solid-form radioactive elements, certain gases, like krypton-86, are clearly dangerous. Krypton-86 is a neutron-activator – it can turn ordinary soil, brick, flesh and air into their radioactive versions.

    Long-lived krypton and xenon and argon gases, like krypton-85 and xenon-133, are all heavier than air and thus they settle near the ground (see footnote 9 ….)

    … a 1995 study published in the journal Applied Radiation and Isotopes noted that ‘Calculations showed that it would take nearly 1 h [hour] to form the total cumulative yield for 137 Cs.’2 Therefore, if xenon-137 gases immediately leak or seep from underground cavities, they have a ‘travel time’ of close to an hour before they fully ‘precipitate’ out into cesium-137….”

    Like

  251. A very informative discussion, if a little heavy on jargon and inconsistent terminology. Here’s my question: if the reactor of Fukushima Daiichi unit #1 had not been shut down completely on detection of seismic activity, would it have been able to survive the events with less risk, damage or cost?

    Like

  252. Worth a detailed look (mentioned above). This looks to me like it’s the source of many of the images being used around the web to explain what’s happening:
    [Magdi Ragheb, U. Illinois at Urbana-Champaign]

    Note it’s copyrighted — cite your source, credit the author.

    An interesting note from that document: see Fig. 17, on p.15 — the “Mark I steel containment design used in 60 percent of USA BWRs” [as of 1986] is the reactor design we’re all studying. From his Table 4:

    Pre Mark I — 4
    Mark I — 22 steel, 2 reinforced concrete
    Mark II — 2 steel, 3 reinforced concrete, 2 post-tensioned concrete
    Mark III — 2 steel, 1 reinforced concrete.

    So the reactors around the US should perform as well as the ones we’ve been looking at — well beyond their design strength.

    My advice to industry (grin):
    Keep those batteries charged. Actively pursue adding nice, big, fields of solar plants, cogeneration, windmills, and pumped water and compressed air power storage around them — so we have multiple redundant power sources _and_ each fission plant has multiple redundant power available right in its back yard. (Then shield them against solar flares).

    AND pursue getting the residential customers well equipped with solar hot water and solar photvoltaic.

    When the worst happens — a solar flare takes out the utility grid for a couple of years, say — the big industrial power supply can either support keeping the reactors working for a while, or take the reactors down gracefully — and supply power from whatever source and the people at home can eke out a more or less comfortable low-power month or year until things get put back together.

    Like

  253. “Mr Goto calculated that because Reactor No 3 at Fukushima-Daiichi – where pressure is rising and there is a risk of an explosion – used a type of fuel known as Mox, a mixture of plutonium oxide and uranium oxide, the radioactive fallout from any meltdown might be twice as bad.”

    When plutonium is used as fuel e.g. in the form of MOX, the neutron spectrum becomes significantly harder than it would be if pure uranium were used. Consequently the effect of neutron absorbers such as boron, xenon and control rods becomes proportionately less i.e. there will be less absorption than if the reactor were fuelled with uranium and the neutron spectrum were softer.

    In addition to the above, the moderator temperature coefficient around MOX fuel tends to be less than it would be for uranium fuel. Consequently the self-limitation of the core becoming less reactive the more the moderator temperature increases will be reduced. This is relevant because in an accident the moderator (water in the case of Fukushima) gets hotter and this temperature rise diminishes the thermalising of the neutrons and therefore dimishes the reactivity of the core. Of course, most of the heat in a tripped reactor is simply the decay heat generated by fission products, but there will still be SOME neutrons created by on-going fission even if they are only the product of spontaneous neutron emission, so it’s good if those neutrons are not thermalised and thus have a better chance of not causing further fissions.

    Lastly the Doppler temperature coefficient is lower in a MOX fuelled core than in a pure uranium core. Just as the moderator temperature coefficient affects the spectrum of the neutrons reaching the fuel, the DTC affects the absorption cross-section of the fuel itself, and thus affects whether a given neutron will be captured and cause a fission.

    All in all, MOX fuelled reactors have less “buffer” in the way they react to temperature changes and, compared to uranium fuelled reactors, require a bit more in the way of absorbers and poisons to keep them under control. In theory this shouldn’t be a problem because a MOX fuelled core will have been designed specifically for the MOX fuel. In practice, though, when adapting an original uranium design to a MOX design some compromises undoubtedly have to be made because the basics of the core e.g. the pressure vessel dimensions can’t be re-optimised. As a consequence there might be a bit of a reduction in the safety margin when using MOX fuel in a reactor design that was originally intended for uranium.

    On top of everything else, a huge amount of experience and literature exists for uranium fuelled designs and accidents, whereas for MOX fuel there is less knowledge and experience. As a result it is easier to imagine a miscalculation or error of judgement when dealing with MOX emergencies.

    Having said all the above, I have confidence in the abilities of the Japanese nuclear engineers, and (standing on my personal soapbox) if I was in the region I’d be more worried about the toxic effects of smoke from refinery fires, water-borne diseases, and straightforward exposure and hypothermia because of loss of electricity production than I would about whether MOX makes another accident more or less likely.

    Like

  254. IAEA update on Onagawa: http://on.fb.me/gM23j7

    The Japanese authorities have informed the IAEA that radioactivity levels at the site boundary of the Onagawa nuclear power plant have returned down to normal background levels. The first (ie lowest) state of emergency was reported at the plant earlier on Sunday after an increased level of radioactivity was detected at the site boundary. Investigations at the site indicate that no emissions of radioactivity have occurred from any of the three units at Onagawa. The current assumption of the Japanese authorities is that the increased level may have been due to a release of radioactive material from the Fukushima Daiichi nuclear power plant.

    The IAEA continues to liaise with the Japanese authorities and is monitoring the situation as it evolves.

    Like

  255. Pingback: Why I am not worried about Japan’s nuclear reactors – From MIT’s Dr. Josef Oehmen « Climate Sanity

  256. Red_Blue, as far as I understand it, the neutrons are basically irrelevant, since criticality stopped when the reactors automatically shut down at the quake.

    Which brings me to another topic – was there any opportunity to keep the reactors running? The main argument against this would be that the grid was down, but both Fukushima sites are multiple reactor – perhaps one could’ve kept running to supply house loads?

    Like

  257. Reality is bad enough.
    http://www.nytimes.com/2011/03/14/world/asia/14nuclear.html?hp

    Partial Meltdowns Presumed at Crippled Reactors
    By HIROKO TABUCHI and MATTHEW L. WALD

    “Officials thought partial meltdowns had occurred at two reactors and were bracing for a second explosion, even as problems were reported at two more nuclear plants….

    … The emergency at the hardest hit plant, Fukushima Daiichi Nuclear Power Station, appeared to be the worst involving a nuclear plant since the Chernobyl disaster 25 years ago, and at least 22 residents near the plant showed signs of radiation exposure, according to local officials. The crisis at that plant, which is much further from Tokyo, continued late Sunday.

    A day after an explosion at one reactor there, Japanese nuclear officials said Sunday that operators at the plant had suffered a setback trying to bring the second reactor thought to be in partial meltdown there under control. The operators need to inject water to help cool the reactor and keep it from proceeding to a full meltdown, but a valve malfunctioned on Sunday, hampering their efforts for much of the day.

    Pressure at the reactor rose during the delay, leading to increased worries of an explosion. At a late-night press conference, officials at Tokyo Electric Power Co., which runs the plant, said the valve had been fixed, but said water levels had not yet begun rising.

    Until late Sunday, the government had declared an emergency at only two nuclear plants, Daiichi and the nearby Fukushima Daini.

    Then, the International Atomic Energy Agency announced that Japan had added a third to the list because radiation had been detected outside the plant, which is about 60 miles from Sendai, a city of 1 million people in Japan’s northeast. The government did not immediately confirm the report from the I.A.E.A., which said it was not yet clear what caused the release of radiation.

    Soon after that announcement, Kyodo News reported that a plant about 75 miles north of Tokyo was having cooling system problems….”

    Like

  258. So the NYT is behind on this news as Barry Brooks posted earlier here — the alarm at Sendai was apparently detecting the releases from the other plants (the winds have been light and variable, apparently).

    Note that the detectors used are _very_ sensitive, likely being done by pulling air through a very fine filter for a long period of time then checking that for radioactivity.

    Anyone who has used a Geiger counter on their laundry dryer lint knows how this procedure concentrates and increases the natural radioactivity, and it would do the same with anything artificial — and the kind of radiation detected would help identify the source.
    _______

    This appears to be the Kyodo News item, I’m guessing: http://english.kyodonews.jp/news/2011/03/77484.html

    Cooling system pump stops at Tokai nuclear power plant 14 Mar 2011 1:55

    One of the two cooling system pumps at the Tokai No. 2 nuclear power plant in the village of Tokai, Ibaraki Prefecture, stopped Friday when a massive earthquake hit Japan but there is no problem with cooling as the remaining pump is working, according to local authorities late Sunday.

    Like

  259. > was there any opportunity to keep the reactors
    > running? … the grid was down, but both Fukushima
    > sites are multiple reactor – perhaps one could’ve
    > kept running to supply house loads?

    No, because the grid is the reliable source; all the others are subject to problems, as we’ve seen. Once the grid is gone, there _should_ have been enough power sources and equipment to handle the steps involved in carefully shutting down, and then actively cooling, the plants. Nobody would throw away any of that safety margin by keeping a fission pile operating, without the grid being available.

    Like

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  262. From reading the various (good) accounts so far, it appears the initial shutdown was automatic.

    Do we know if there was any actual damage caused by the earthquake, to the main systems or cooling systems?

    After that shutdown, and before any of the other failures, would it have been possible to restart the reactor, to remove the dependency on the diesel and battery power for running the cooling systems?

    At what point did they lose the ability to restart?

    (There might not be enough information available yet, but it is something that I think would have been wise to consider, at least with 20/20 hindsight.)

    Brian

    Like

  263. Good clarification here:
    http://www.chicagotribune.com/news/nationworld/la-sci-japan-quake-reactor-qa-20110314,0,7463052.story

    “Japanese authorities say there has been a partial meltdown. What does that mean?

    That statement is based on the detection of extremely small quantities of the isotopes cesium-137 and iodine-131 in the environment near the plant. Those two elements are byproducts of uranium fission. During the normal operation of a reactor, cesium-137 and iodine-131 migrate to the gap between the fuel pellets and the zirconium cladding. The fact that some quantities escaped into the environment suggests the cladding heated up and cracked to some degree. That does not mean any fuel has melted, although it is possible that a small amount did. Barring a major catastrophe, no one will know whether fuel has melted until they can get into the containment vessel and examine it.

    Most likely, the company would keep pumping seawater through it for several years until it had cooled down sufficiently and many of the radioactive isotopes had decayed enough that engineers could go in and remove the fuel. That, in essence, is what happened in 1979 in the partial core meltdown at the Three Mile Island Generating Station in Pennsylvania. “

    Like

  264. > would it have been possible to restart the reactor

    Remembering I’m a pure amateur reader here, you can find better answers from Google (grin):

    Any sudden shutdown has to be followed by a careful recovery, it’s not like turning off a light switch; a whole lot keeps changing for a while.

    “When Enrico Fermi fired up the first nuclear reactor at Hanford in 1944, he was in for quite a surprise. Shortly after the reactor went critical, power stalled and the reactor shut down. A few hours later, the reactor unexpectedly started up again all by itself….”
    http://nuclearfissionary.com/2010/05/06/nuclear-fission-for-dummies-xenon-135/
    Read that for a bit about what happened to Fermi and how things are changing in a fission reactor.

    This sort of thing takes serious study. The behavior changes over time and that has to be very well understood to bring it to a stable well understood configuration before starting the reaction up again.

    Here for example from coursework
    http://www.nuceng.ca/br_space/class/Module3D_XenonJun21.pdf

    “the large and rapid build-up of additional Xenon reactivity load following a reactor trip can cause an extended (approximately 40 hours) of reactor shutdown …”

    Like

  265. Hank, I’ve seen proposals that nuclear plants could be designed to keep running in the event of loss of external grid power – to act as points from which the grid can be restarted, in fact. Not necessarily an easy task but one worth doing I’d think.However clearly for such an exacting infrastructure role there should be some reward to a commercial operator also, in the context of the US system at least.

    Like

  266. We rely upon advanced technology to provide us the productivity based benefits that are the basis of our lifestyle and compensation system.

    All forms of advanced technology carry with them risks. To pretend otherwise is foolish.

    If we want risk free lives then we must give up the benefits that come from technological advances in quality of life and productivity.

    We have over 100 nuclear power plants in the USA, and none of them has had an issue since Three Mile Island.

    There is no free lunch. If we want to continue to advance as a society, and compete with less technologically advanced societies who have more people but less technology than we do (India, China), then we need to continue to take managed technological risks.

    For us to turn our back on nuclear power when it is the only source of carbon free and affordable power, because of politically correct scare-mongering would be a travesty.

    Like

  267. Joffan,

    At Daiichi they cannot immediately restart the 3 reactors that were tripped… but perhaps they could consider one of the three which were shut down for maintenace for back-up duties as you suggest… if any one of them are near ready for restart.

    Like

  268. http://www.reuters.com/article/2011/03/13/us-japan-quake-experts-idUSTRE72C2M020110313?pageNumber=3

    “The problem is that worldwide there are lots of operating reactors built in early 1970’s. I think that (after this catastrophe) the oldest plants will simply be closed and new compensatory ones will be built, unless political situation turns dramatically and nothing gets built.”

    “In the United States, there are 100 plants, and half of those are built in 1970’s” …”

    —-
    TEPCO’s website is very, very slow; here’s a chunk from the last press release:

    Press Release (Mar 13,2011)
    Plant Status of Fukushima Daiichi Nuclear Power Station (as of 9pm March 13th)
    “- We are currently coordinating with the relevant authorities and departments as to how to secure the cooling water to cool down the water in the spent nuclear fuel pool.”
    ————-

    Like

  269. http://www.zerohedge.com/article/iaea-refutes-reactor-3-cooling-problems-provdes-fukushima-status-update?page=1

    IAEA Refutes Reactor 3 Cooling Problems, Provides Fukushima Status Update; Credibility Schism Developing In Japan
    03/12/2011 20:56 -0500
    Contrary to earlier reports that cooling at Reactor 3 at Fukushima has failed (as per CNN and Reuters) and there is now a state of emergency for three reactors at the site, the IAEA has released a report refuting these rumors. It appears that there is a split in news reporting in Japan: on one hand we have the Nuclear and Industrial Safety Agency which seems to present a downside case, while the government is obviously spinning news in a favorable direction….”

    ——-
    http://www.iaea.org/newscenter/news/tsunamiupdate01.html
    Japan Earthquake Update (14 March 2011 01:30 CET)

    Based on information provided by Japanese authorities, the IAEA can confirm the following information about the status of Units 1, 2 and 3 at Fukushima Daiichi nuclear power plant.

    Unit 1 is being powered by mobile power generators on site, and work continues to restore power to the plant. There is currently no power via off-site power supply or backup diesel generators being provided to the plant. Seawater and boron are being injected into the reactor vessel to cool the reactor. Due to the explosion on 12 March, the containment building has been lost.

    Unit 2 is being powered by mobile power generators on site, and work continues to restore power to the plant. There is currently neither off-site power supply nor backup diesel generators providing power to the plant. The reactor core is being cooled through reactor core isolation cooling, a procedure used to remove heat from the core. The current reactor water level is lower than normal but remains steady. The containment building is intact at Unit 2.

    Unit 3 does not have off-site power supply nor backup diesel generators providing power to the plant. As the high pressure injection system and other attempts to cool the reactor core have failed, injection of water and boron into the reactor vessel has commenced. Water levels inside the reactor vessel increased steadily for a certain amount of time but readings indicating the water level inside the pressure vessel are no longer showing an increase. The reason behind this is unknown at this point in time. To relieve pressure, venting of the containment started on 13 March at 9:20AM local Japan time. Planning is underway to reduce the concentration of hydrogen inside the containment building. The containment building is intact at Unit 3.

    The IAEA is seeking information about the status of spent fuel at the Daiichi plant.

    Like

  270. http://www.ucimc.org/content/meltdowns-grow-more-likely-fukushima-reactors

    by Robert Alvarez
    “Robert Alvarez, an Institute for Policy Studies senior scholar, served as senior policy adviser to the Energy Department’s secretary and deputy assistant secretary for national security and the environment from 1993 to 1999.”

    “… Along with the struggle to cool the reactors is the potential danger from an inability to cool Fukushima’s spent nuclear fuel pools. They contain very large concentrations of radioactivity, can catch fire, and are in much more vulnerable buildings. The ponds, typically rectangular basins about 40 feet deep, are made of reinforced concrete walls four to five feet thick lined with stainless steel.

    The boiling-water reactors at Fukushima — 40 years old and designed by General Electric — have spent fuel pools several stories above ground adjacent to the top of the reactor. The hydrogen explosion may have blown off the roof covering the pool, as it’s not under containment. The pool requires water circulation to remove decay heat. If this doesn’t happen, the water will evaporate and possibly boil off. If a pool wall or support is compromised, then drainage is a concern. Once the water drops to around 5-6 feet above the assemblies, dose rates could be life-threatening near the reactor building. If significant drainage occurs, after several hours the zirconium cladding around the irradiated uranium could ignite.

    Then all bets are off.

    On average, spent fuel ponds hold five-to-ten times more long-lived radioactivity than a reactor core. Particularly worrisome is the large amount of cesium-137 in fuel ponds, which contain anywhere from 20 to 50 million curies of this dangerous radioactive isotope. With a half-life of 30 years, cesium-137 gives off highly penetrating radiation and is absorbed in the food chain as if it were potassium.

    In comparison, the 1986 Chernobyl accident released about 40 percent of the reactor core’s 6 million curies. A 1997 report for the Nuclear Regulatory Commission (NRC) by Brookhaven National Laboratory also found that a severe pool fire could render about 188 square miles uninhabitable, cause as many as 28,000 cancer fatalities, and cost $59 billion in damage. A single spent fuel pond holds more cesium-137 than was deposited by all atmospheric nuclear weapons tests in the Northern Hemisphere combined. Earthquakes and acts of malice are considered to be the primary events that can cause a major loss of pool water.

    In 2003, my colleagues and I published a study that indicated if a spent fuel pool were drained in the United States, a major release of cesium-137 from a pool fire could render an area uninhabitable greater than created by the Chernobyl accident. We recommended that spent fuel older than five years, about 75 percent of what’s in U.S. spent fuel pools, be placed in dry hardened casks — something Germany did 25 years ago. The NRC challenged our recommendation, which prompted Congress to request a review of this controversy by the National Academy of Sciences. In 2004, the Academy reported that a “partially or completely drained a spent fuel pool could lead to a propagating zirconium cladding fire and release large quantities of radioactive materials to the environment.”

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  271. Pingback: Too little of late, and now Japan: a roundup « Politics’n'Poetry

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  273. Good brief discussion here:
    http://boards.straightdope.com/sdmb/showthread.php?t=600501

    Several people commenting gave a variety of links there:

    http://www.nrc.gov/reading-rm/doc-collections/nuregs/staff/sr0933/sec3/082r3.html
    Resolution of Generic Safety Issues: Issue 82: Beyond Design Basis Accidents in Spent Fuel Pools (Rev. 3) (NUREG-0933, Main Report with Supplements 1–33)

    http://www.nap.edu/openbook.php?record_id=11263&page=38
    Safety and Security of Commercial Spent Nuclear Fuel Storage: Public Report (2006)
    Board on Radioactive Waste Management (BRWM)

    http://spectrum.ieee.org/energywise/energy/nuclear/japan-nuclear-accident-worse-than-worst-again
    Japan Nuclear Accident: Worse than Worst, Again
    Bill Sweet / Sat, March 12, 2011

    http://www.cfr.org/weapons-of-mass-destruction/nuclear-spent-fuel-pools-secure/p8967
    Are Nuclear Spent Fuel Pools Secure?
    Speaker: Kevin Crowley
    June 7, 2005, Council on Foreign Relations

    Like

  274. em1ss, sodium has not been abandoned as a coolant for power generating plants. It looks like the best choice for fast reactors. Check this out:
    http://www.ne.doe.gov/pdfFiles/SodiumCoolant_NRCpresentation.pdf

    And from wikipedia: “The fast reactors offer the possibility of burning actinides to further reduce waste and of being able to breed more fuel than they consume. These systems offer significant advances in sustainability, safety and reliability, economics, proliferation resistance and physical protection.”

    Sorry for slightly off-topic content… but to me, the take-home message of Fukushima is: we need to bring next-generation plants online quickly. The older designs are problematic.

    Like

  275. Hank:

    did you read the ieee piece? Do you know much about them (ieee)?

    here’s a sample:

    “Operators also are injecting boron into the reactor vessel to head off a re-criticality–a situation in which melting fuel reconfigures itself and starts reacting self-sustainably again.”

    “recriticality”?

    The article also proclaimed the accident second worst ever.

    Recriticality would require a chain reaction, not an increase in decay heat due to lack of coolant.

    am I mistaken here, or is this guy purposefully conflating LOCA and criticality incidents? I have seen this over and over.

    Barry: this is absolutely maddening. Unless I am missing something.

    Like

  276. I’m no expert… just an interested observer…

    “recriticality” – I think the chain of events meant to be described is:
    (1) Loss of cooling ability (e.g. loss of coolant)
    (2) Uncontrolled heating of the core
    (3) Melting fuel rods
    (4) Molten fuel in the fuel rod tubes filling spaces, reaching higher densities, and thus levels of free neutrons (from spontaneous fission) than can be managed via control rods alone (i.e. reaching criticality)

    Adding boron, aka “liquid control rods” into the cooling spaces, gives an extra margin of avoiding criticality even if fuel rods melt (a bit?).

    That’s my uneducated take on the meaning of the term, in the context of the article.

    Like

  277. Gregory Meyerson, – they seem legitimate, but I haven’t looked at the content in detail. However it does look like these are mostly opinions, and as such must be weighed by who is holding them, rather than the venue in which they reside.

    Like

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  280. Just want some “lay-person, oil industry controls engineer” clarification on Fukushima Daiichi No 1 …

    My understanding is that secondary containment in a 1970s GE BWR-1 (outwith the RPV) is the concrete “dry well”.

    I’m more than curious if the H2 explosion at No 1 was within the dry well with all its exposed controls / valves / torus supression pool (scary) and “blew the lid” … or just a superficial blast in the service housing above, which looks more probable looking at photos ?

    But how did hydrogen leak or release there … thought venting was within the turbine hall … no obvious stack that I can see …

    We need facts to counter the s**t even the BBC are putting out, “charlatan engineers” who want to see the death of the only power source that can see civilisation survive post-oil !

    Also what about the pools for the spent fuel rods, now seemingly exposed to the environment, is the boraic acid cover still OK ?

    Why are we not getting this info ?

    Like

  281. > recriticality

    That’s not from the heat of radioactive decay, remember. Criticality means slow neutrons hit fissionable atoms and so cause enough additional fission events to produce a slightly larger number of slow neutrons, which produce more fission events. Those kinds of accidents have happened in many ways.

    They’re adding water to the core; water slows fast neutrons down. If the core fell apart, leaving a pile of fuel rods at the bottom of the container–criticality could happen in that situation. So they’re adding boron, which soaks up neutrons.

    They don’t know what’s happening inside these bottles. So they’re adding boron just in case.
    —-

    And Reactor 3 has had an explosion. Not much info yet.
    http://www.world-nuclear-news.org/RS_Explosion_rocks_third_Fukushima_reactor_1402111.html

    14 March 2011
    First published: 3.08am GMT

    … this time at the third reactor unit. Initial analysis is that the containment structure remains intact.
    … water injection operations have continued and pressure readings from the reactor system remained within a comfortable range. ….Seawater was being injected into the reactor vessel and levels had initially risen as expected. However, a gauge indicated that the rise had tailed off, despite ongoing seawater injection.

    The gauge in question indicated that water levels are around two metres below the top of the nuclear fuel assemblies, which would represent a very serious situation with the risk of fuel damage….”

    Like

  282. DOH … reaction has been poisoned (verified on all reactors) … how does adding water as a supposed moderator make something dead come alive ?

    Adding water will never restart a reaction with virtually nil neutron flux …

    I’m an engineer and understand how you would build a reactor, understand negative coefficient design, the use of control material.

    Hopefully the compromised fuel / control assembiles will be extracted at some point, and the sites rebuilt with most reactors up and running within the year ?

    Its not an option, its the way that most countries have to look for their power in a world of dwindling oil ???

    Like

  283. At this point I wonder why they haven’t taken off some of those upper deck side panels and let the air blow through there, so hydrogen can’t accumulate.

    It would be a tradeoff — it would defeat the described “secondary containment” function (assuming they do have fans running and negative air pressure throughout the building.

    If the negative pressure fans are running they’re presumably pushing the exhaust air through the standard filter system. But do they even have enough electric power for that system to operate, anyone know? If it’s not operating, taking a few sheets of sheet metal off the upper walls for ventilation wouldn’t lose any protection and could let hydrogen escape.

    More amateur speculation on my part, nothing more.

    Like

  284. laura_eva, again, look back in the thread, there are diagrams of the location; the pool is a very deep hole in the concrete; the sketches show where the spent fuel is located, down under 20 feet of water, alongside the top of the reactor vessel, below the big orange crane.

    What blew off the top is sheet metal — leaving the framework behind. Yes, it’s a concern. Several press releases quoted above mention the issue — they need to have water circulating in the spent fuel pool and be adding water as needed to keep the level up.

    But losing some sheet metal over the top isn’t going to mess that process up too badly, compared to the other issues.

    It does mean whatever negative pressure system they were using to draw air in and filter it is gone, so they’re relying on the big concrete primary containment now and on the steel bottle inside that, but they were already venting steam and so not really containing much with that sheet metal roof.

    Or so I’d guess. I’m just another blog reader. But seriously, do look back, there is a lot of good info and most questions have been asked and answered so far earlier in the past three days.

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  286. Whoah, this is alarmingly wrong:

    > laura_eva, on 14 March 2011 at 3:23 PM said:
    > DOH … reaction has been poisoned (verified
    > on all reactors) … how does adding water as a
    > supposed moderator make something dead
    > come alive ?
    >
    > Adding water will never restart a reaction with
    > virtually nil neutron flux …
    >
    > I’m an engineer …

    Maybe. Maybe not. Citations needed for factual claims.

    Try looking: http://www.google.com/search?q=Criticality+Safety+in+the+Waste+Management+of+Spent+Fuel

    From the first hit:
    “Criticality Safety in the Waste Management of Spent Fuel from NPPs
    Robert Kilger
    Abstract:
    During irradiation in the reactor core, fissile material from nuclear fuel is depleted for power generation. However, significant amounts of fissile nuclides, mainly 235U and 239Pu, are still present in spent fuel unloaded from the core, with the inherent potential for maintaining an inadvertent nuclear chain reaction under unfavorable conditions. Due to this reason, criticality safety has to be demonstrated for all stages of waste management of spent nuclear fuel. This pertains e.g. to wet storage in cooling ponds, dry storage and transport of the fuel in casks, dissolver stages in reprocessing plants, as well as the direct final disposition of the spent fuel. Usually, for system design the reactivity of the spent fuel has been considered as being equal to fresh fuel…..”

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  288. From the engineers, for the engineers:
    ———————–
    http://www.bazley.net/institute/archives/archives.html
    ———————–
    What Is a Crit Engineer and What Is Criticality Safety?

    Trying to Find Short Definitions for the Practitioner and Layman

    After experiencing the holidays and having to answer a few more questions from friends and relatives about what we, as nuclear criticality safety engineers, do, the Institute has started work on generating a few web pages to explain to the layman (“—or woman” to quote Life of Brian) what criticality safety is and what a criticality safety engineer does. Along this endeavor, we started looking for some short definitions of who we are and what we do.

    Of course, we stumbled upon the classic definitions of some individuals of the criticality safety community. But those definitions were lacking in perspective of what our jobs as engineers were. We could only find one simple definition of what a criticality safety engineer is.

    The short definitions are provided below in hopes that a few of you would provide us with some more insight (and hopefully some of your artistic prose) into other or more meaningful definitions of criticality safety and criticality safety engineering. (And would also provide us with any already existing celebrity definitions missed.) We’ll add your definition to our list giving you the appropriate credit. Thanks for your help!

    Definitions of Criticality Safety

    Protection against the consequences of an inadvertent nuclear chain reaction, preferably by prevention of the reaction. — ANSI/ANS-8.1-1998

    The art of avoiding a nuclear excursion. — Hugh Paxton

    The art and science of not building a nuclear reactor without shielding, coolant, and control — Francis Alcorn

    Definitions of a Criticality Safety Engineer

    One who, typically by trial and error, realizes that one can not intuitively predict the change in reactivity by any change in any nuclear parameter. — Chris Miller
    ———————————————–

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  297. Interesting night it seems. Another Hydrogen explosion at Unit 3. Buried in these posts is something I forgot about. Hydrogen injection to Feedwater for Hydrogen Water Chemistry.

    Alot of BWRs have implemented this to minimize O2 in the vessel and corrosion. This system should shutdown automatically on a scram by most designs. Possibly this is part of the equation for buildup of H2 in the Reactor Buildings.

    The discussion about the spent fuel pools backs up that a loss of level will result in significantly increased radiation dose rates as the water level drops.

    Continue to monitor reports for this significant increase in radiation levels near the Reactor Buildings and on Site. Otherwise it is safe to assume spent fuel pool level is ok or being maintained adequately above the spent fuel.

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  299. Laura, with regards to Spent Fuel Pool exposure. The surface of the pool is normally exposed to the refueling floor, which is the top of the Reactor Building. With panels blown off and Roof sections of the top floor of the building the surface of the pool is exposed to the environment.

    As long as they keep water in the pool, radiation levels and spent fuel damage will not occur thermally. As described in other posts last night the pool it self is quite a robust concrete walled structure with a steel liner.

    However who knows what fell into the pool and may have caused some damage to the fuel assemblies stored there. Based on reported rad levels and airborne activities it doesn’t seem like this type of damage has occurred as of yet nor a loss of pool water level of significance.

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  300. “While many krypton and xenon gases are less radioactive than most solid-form radioactive elements, certain gases, like krypton-86, are clearly dangerous. Krypton-86 is a neutron-activator – it can turn ordinary soil, brick, flesh and air into their radioactive versions.”

    Somewhere, the anti-nuclearists actually sit around and they actually make up this crap completely out of thin air. They seem to just pick an element at random, and pick a mass number at random (and not check the table of nuclides to see if it actually exists, or if it’s a stable isotope) and they say that this is the deadly radioactive evil that’s being spewed from the reactor.

    Kr-86 is a stable (non-radioactive) nuclide, which comprises 17% of natural krypton.

    Like

  301. i would like to know, if the heat is great enough, in conjuction with the zirconium as an catalyst, to split the water into hydrogen and oxygen, which the zirconium reacts with the oxygen and are left with just the hydrogen as a free gas, when seawater is being used does it also split the NaCl in the seawater producing Clorine gas as well, and if so what type of additional danger could that pose?

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  319. Greg… Sorry, I haven’t got a notice on my computer for that, but if it is I will let the nukeworker.com webadmins know. Interesting that it is though. That thread is by people who operate reactors in the US.

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  322. > krypton-86

    Thanks, Luke, confirming the guy’s “not even wrong” krypton-86 is stable: http://www.wolframalpha.com/entities/isotopes/krypton_86/ve/4s/6l/
    Being an “anti” site is no excuse for sloppy.

    Looking that up led to this:
    http://www.springerlink.com/content/g1764405737222m5/

    Journal of Radioanalytical and Nuclear Chemistry
    Volume 220, Number 2, 173-181, DOI: 10.1007/BF02034852
    Monitoring of fission product release in a boiling water reactor
    Only the first page is shown as a picture, it’s paywalled.

    Google excerpt is: “klypton-87, krypton-88, krypton-85m, xenon-135 and ….. (2.1 y) is produced by neutron activation of 133Cs, a stable fission product. …”
    [Yeah, it does say “klypton” — bad OCR by Google?]
    http://www.springerlink.com/index/g1764405737222m5.pdf

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  323. For Luke — follow up, the “86” was clearly a typo, and the guy has it correct elsewhere:

    “… Kr-87 has a half-life of 1.27 hours … Kr-87 is an example of a ‘delayed neutron,’ a fission product that emits neutrons after the ‘fission event.'”

    So it is in fact a neutron activator, to the extent it’s a delayed neutron emitter — a class of radioactivity I didn’t know existed til today. That’s not a certainty, it’s a low-probability decay path for that isotope, which decays very fast and can go several different ways when the nucleus comes apart, emitting either a beta or a neutron, as I read it.

    Still the point is that the noble gas isotopes will get out through almost any containment or filter, though they can be adsorbed, and when they decay some will produce solid elements wherever they happen to be. Dunno how significant a source this is, anyone know?

    More: http://www.google.com/search?q=krypton+87+neutron

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  325. And here’s the percentage, it’s quite low; I emailed the contact info about both the “86” typo (should be 87) and suggesting the percentage info be included.

    Nuclear energy: principles, practices, and prospects – Google Books Result
    David Bodansky – 2004 – Science – 693 pages
    … proceeds to a number of different states of krypton- 87 (87Kr, Z = 36). In 2.3% of the cases, the resulting 87Kr state decays by neutron emission to …
    books.google.com/books?isbn=0387207783…

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  328. NPR radio news just now says Reactor 2 has a stuck valve preventing them from getting water into the core.
    ABC news website:
    http://www.abc.net.au/news/stories/2011/03/15/3163913.htm
    “Operators won’t rule out nuclear meltdown
    Updated 8 minutes ago
    The nuclear emergency in Japan following Friday’s massive earthquake and tsunami has worsened, with the operators of the damaged Fukushima nuclear plant warning they are fighting to prevent a meltdown.
    … government officials are playing down the nuclear concerns, insisting the situation is under control.

    The fuel rods in the No.2 reactor at the quake-damaged plant are again “fully exposed”, boosting fears of an eventual partial meltdown.

    Air pressure inside the reactor at the Fukushima No 1. plant rose suddenly when the air flow gauge was accidentally turned off, operator TEPCO said early Tuesday (local time).

    That blocked the flow of cooling water into the reactor, leading to full exposure of the rods about 11pm on Monday, it said.

    “We are not optimistic but I think we can inject water once we can reopen the valve and lower air pressure,” a TEPCO official told reporters….”

    ———
    Information on how this started that I had not seen before, from
    http://www.greenaction-japan.org/modules/wordpress1/index.php?p=2

    “This explanatory piece arrived at 17:55 from Takeshi Sakagami:

    Fukushima Daiichi Nuclear Power Station Unit 2 lost its cooling system at 13:26pm.
    Unit 2 was initially expected to have a possible core meltdown earlier than Units 1 and 3.

    Estimating by the release of information from the Prime Minister of Japan and his Cabinet, as well as news media coverage, the tsunami hit Fukushima Daiichi Nuclear Power Station 50 minutes after the earthquake at 15:40 on the 11th, causing the emergency diesel generators to stop functioning. The Reactor Core Isolation Cooling pump of Unit 2, however, activated its water injection system the moment the reactor automatically shutdown.

    A problem occurred at 20:30 when the M/C (Main Switchboard) was submerged underwater. This prevented proper monitoring of pump operations and the reactor’s water levels. The situation had to be managed without proper information from the site.

    As a result, at 20:50, Fukushima Prefecture released an evacuation order for those living within 2km of the reactor. The government also released an evacuation order at 21:23 for those living within 3km and a stay-home order for those within 10km of the reactor. The government’s orders were released following prefectural correspondence.

    TEPCO and NISA (Nuclear and Industrial Safety Agency) made two predictions for pump malfunctions at 21:00 and 22:00. The prediction for 22:00 had fuel exposure at 22:50, meltdown at 24:50, and a reactor containment “bent” (intentional release of pressure) at 27:20.

    At 21:54, water levels were identified as L2(low-low) using temporary power. However, since this temporary power lasted only a short time, there were measures to secure an electric power supply through a power source car. This trial failed, as they could not connect to the source.
    The predicted time for meltdown and reactor containment vessel venting
    (outer air release) passed without successful power connection.

    However, the Reactor Core Isolation Cooling pump was operating. This information was discovered 13min after the predicted time for a reactor containment vessel bent. Water injection continued.
    While this was happening, the Unit 1 situation got worse, as its pump was not operating. Problems occurred in Unit 1, followed by Unit 3.

    Unit 2’s current state of problems include deterioration of the Reactor Core Isolation Cooling pump function, rising pressure in the reactor, and a lowered water level. NISA stated they would try recovering pump functions by lowering pressure through a reactor containment vessel venting (releasing radioactive inner air to the outside). Sea water was used so as to keep as much water as possible in the reactor containment vessel’s suppression pool.

    (translation by a volunteer translator)”

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  330. Seen in retrospective the action should be more prompt when it became clear that the plant suffered multiple failures. Bringing in ships, helicopters and using what was available to power up those pumps, if so by bypassing power directly. Or if coupling external pumps in series to get the water in. As i understrand you don’t need more than 30 bar pressure to get water into the boiler.

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  332. Alright guys. I have looked at aerial photos on unit 3 (http://www.flickr.com/photos/digitalglobe-imagery/5526481182/sizes/o/in/photostream/) any thoughts on the significant steam offgas that looks like it is coming from near the top of the primary containment? I dont think it is the spent fuel pool, as the steam release looks to concentrated in one place. Could it be the connection for primary containment venting to the secondary containment via SGTS?

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  333. I am a nuclear ISI engineer. The technical discussion of the safety of these Japanese plants is exactly correct. People need to understand these plants are not bombs. They are not chernobyl, they are fail safe designed. People need to be aware that to environmental groups these plants are “boogie men”.
    Ask yourself this question. Nuclear plants have operated safely in the United States for over Fifty years.
    How many people have been killed by a Nuclear plant in the United States? More coal miners have been killed in a single mining accident than all of the workers combined over fifty years in a Nuclear plant. And most were not related to radioactivity. How many outside the boundary of a Plant…none
    Here is your choice…keep paying outrageous gas prices and be held hostage to foreign oil or advocate for the nuclear power industry and tell the environmentalists to back off because they have no grounds to demonize this industry. You have a greater risk of dying in a plane crash than from a nuclear plant, period.

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  336. Units 1 & 3 appear to be stable based on reports. Unit 2 is now of concern. Unit 1 & 3 have long term issues to deal with in the spent fuel pools. Those issues can be overcome though barring another act of mother nature.

    Continue to watch the reports of radiation levels on site and at the site boundary and airborne release rates. If they really shoot up, things have gone bad. Unit 2 could be the one that causes real problems though as we monitor the situation.

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  337. James, I am really beginning to believe that the hard pipe mod to vent the torus straight to the stack wasn’t done, or failed due to isolation valve failure. Hence the hydrogen buildup in the reactor building and ultimate explosion for units 1 & 3.

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  339. Can someone please explain how the seawater is being injected? IANAE (I am not an engineer.) So pretend I’m a teenager …

    I understand that a closed vent is preventing the process, but what IS the process? If there is no power, how is the water being injected?

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  340. Buckeye, look earlier in this long thread for pictures and sketches; there are quite a few pipes going into various parts of the reactor containment, and diesel pumps are being used. It’s not clear what particular pipes and valves are used or not used or failed, from what I’ve read.

    Status:
    http://www3.nhk.or.jp/daily/english/14_46.html
    (Japan Broadcasting Corporation)
    updated at 13:40 UTC, Mar. 14

    The utility firm said on Monday afternoon that fuel rods are exposed at the Number Two reactor of its Fukushima Number One plant after the level of coolant water dropped. At around 6:20pm, the power company began pumping in seawater.

    Tokyo Electric says it had to halt the process due to fuel loss for the pumping system, possibly leaving the fuel rods in the reactor exposed. The firm says a core meltdown might have occurred.

    The Nuclear and Industrial Safety Agency says that pumping seawater into the reactor is working now.

    Earlier in the day, the firm told the government that the reactor had lost all cooling capability due to a failure of the emergency power system.

    Since then, the company has tried to circulate the coolant by steam instead of electricity. But attempts to lower the temperature inside the reactor chamber have not worked well.

    The company is also considering opening a hole in the reactor housing building to release hydrogen generated by the exposed fuel rods.

    Accumulated hydrogen has caused blasts at two other reactors at the plant.

    Monday, March 14, 2011 20:36 +0900 (JST)

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  341. http://www3.nhk.or.jp/daily/english/14_16.html

    “TEPCO says the water-drenched equipment and machinery short-circuited after the power plants were submerged in sea water on Friday.
    Based on the government’s guidelines, the Fukushima No. 1 plant was designed to withstand tsunami waves of up to 5.7 meters and the No. 2 plant, up to 5.2 meters.

    TEPCO says the tsunami waves that hit the plants were higher than 10 meters.

    Monday, March 14, 2011 09:53 +0900 (JST)”

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  342. Could be a silly question here guys, so hold on…

    Saw on the news last night footage from inside a reactor. It’s the news, so obviously they didn’t mention where it was.

    This footage showed a ‘pool’ in a builbing, and something that looked like a reactor core at the bottom. Sort of hexagonal honeycomb of rods and things.

    So, I’m just trying to marry up this image to how the plant works. The rods get hot and make steam. Is this bath the heat exchanger that provides steam, or the cooling water around the core? Is only the reactor pressurized?

    Barry, have you done a ‘Nuclear plants for dummies, that know a little bit already’ post?

    EB

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  343. Hank, thank you. I did try to review those diagrams before asking. I see the descriptions and locations labeled where the seawater is being pumped in.

    My question is about the basic physics of getting the water in. Is the water being pulled down into the containment via gravity, forced in by high pressure, or …? Please excuse my ignorance. (IANAE)

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  344. Hank, injection of fire water or sea water is standard protocol for accident mangement. What is really critical is did it get in… and what are the current radiation levels….

    As you said there are many ways to inject if pressure is low enough, some more efficient than others… I hope you understand what you are reading on the internet as it must be filtered….

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  345. I’m not an engineer, just reading. From the quotes above, they do have some electric power and fuel, not enough fuel sometimes, to run ordinary electric or diesel pumps that they have been using.

    I don’t know what “the company has tried to circulate the coolant by steam instead of electricity” means.

    All the reporters are saying it’s hard to get reliable information. A lot of this won’t get clear until the crisis is over.

    Like

  346. Like

  347. thanks to em1ss and please, critique and comment and point to better sources as much as you can. You’re among the very few commenters who actually know what they’re talking about here.

    (I’m not, I’m just trying to filter what I read not to add opinion nor link to anything that doesn’t cite sources; it’s getting harder to sort out sense from crap as this goes on, tho’–I’m hoping we see some known reliable commenters take on a full time feed, but until the companies and government supply facts, that’s not likely).

    http://www.world-nuclear-news.org/RS_Loss_of_coolant_at_Fukushima_Daiichi_2_1403113.html

    Loss of coolant at Fukushima Daiichi 2
    14 March 2011 FIRST PUBLISHED: 6.14pm
    UPDATE 1: 8.04pm Information from Tepco television appearance

    “A spokesman for Tokyo Electric Power Company has appeard on national broadcaster NHK to explain the company’s efforts to control unit 2’s reactor core after its isolation cooling system failed following an increase in containment pressure to some 700 kPa.

    The company prepared to inject seawater into the reactor system, but this was only started “after the water level reached the top of the fuel.” Guages indicated that water levels continued to drop despite the injection process and after some time injection became impossible due to high pressure.

    Opening the relief valve made injection possible again, but after a time pressure relief was again required. Injection has continued since that second venting operation but guages still do not indicate that water levels are rising.

    The Japan Atomic Industry Forum reported back statements from the Nuclear and Industrial Safety Agency (NISA) saying that Tepco made a notification at 8.50pm that some fuel rods were presumed broken, based on radiation detected.”

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  348. evcricket, that sounds like a open-pool research reactor. While they generate some heat of course, it’s low quantities and there is no attempt to use the heat for power generation.

    A power reactor is in an enclosed pressure vessel; the coolant carries the heat to turbines (possibly via heat exchangers).

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  349. I ask again, what are the radiation levels currently…. This is protocol response and may be working, but radiation levels determine effectiveness…

    Some fuel rod leakage or fuel damage should be expected if as reported the fuel was uncovered for the reported amount of time. Key now for reactor 2 is covering the fuel and maintaining containment through flooding.

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  351. http://search.japantimes.co.jp/cgi-bin/nn20110315x1.html

    “Tuesday, March 15, 2011
    …No. 2 reactor at the quake-hit Fukushima No. 1 nuclear power plant, as fuel rods became fully exposed again after workers recovered water levels to cover half of them in a bid to prevent overheating.

    The plant operator, Tokyo Electric Power Co., said steam vents of the pressure container of the reactor that houses the rods were closed probably due to the battery problem, raising fears that its core will melt at a faster pace.

    The firm said it will first lower the pressure of the reactor by releasing radioactive steam and open the vents with new batteries to resume the operation to inject seawater to cool down the reactor.

    Earlier, cooling functions of the reactor failed, causing water levels to sharply fall and fully exposing the fuel rods for about 140 minutes. TEPCO said they could not pour water into the reactor soon as it took time for workers to release steam from the reactor to lower its pressure, the government’s nuclear safety agency said.

    As TEPCO began pouring coolant water into the reactor, water levels went up at one point to cover more than half of the rods that measure about 4 meters.

    Prior to the second full exposure of the rods around 11 p.m. Monday, radiation was detected at 9:37 p.m. at a level twice the maximum seen so far— 3,130 micro sievert per hour — near the main gate of the No. 1 plant, according to TEPCO.”

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  352. http://search.japantimes.co.jp/cgi-bin/nn20110315a1.html

    Tuesday, March 15, 2011

    Reactor fuel rods fully exposed
    Coolant failure now reported in No. 2 unit

    By KANAKO TAKAHARA
    Staff writer

    The radioactive fuel rods at the No. 2 reactor of the Fukushima No. 1 power station were fully exposed at one point Monday, Tokyo Electric Power Co. said, raising the possibility that it suffered a partial core meltdown.

    The utility operating the Fukushima plant later said the level of coolant water in the reactor’s container was raised 2 meters above the base of the rods — which are about 4 meters long.

    However, it was not clear if Tepco was able to pump enough coolant into the containment vessel to cool it off. Nevertheless, Chief Cabinet Secretary Yukio Edano told a news conference Monday evening that the situation stabilized after cooling resumed.

    Fears of the worst-case scenario — a total core meltdown — are increasing because the No. 2 reactor’s self-cooling system failed and sea water was being pumped in from outside.

    Tepco said the water levels fell because the pump temporarily ran out of fuel and workers failed to notice it quickly enough.

    It was not immediately clear how long the reactor’s core lay fully exposed or to what extent it heated up in that time….”

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  353. according to the http://www.nisa.meti.go. site’s latest press release:

    →29.8 micro Sv/h(14:14 March 14)
    MP5 (Monitoring at north-west Site Boundary for Unit 2)
    6.1 micro Sv/h(14:02 March 14)
    MP6 (Monitoring at the west –southwest Site Boundary for Unit 2)
    3.70 micro Sv/h(16:10 March 14)
    →4.2 micro Sv/h(12:34 March 14)
    MP7 (Monitoring at the west –southwest Site Boundary for Unit 2)
    6.1 micro Sv/h (12:16, March 14)
    (3) Wind direction/wind speed (as of 14:14, March 14) at MP-4
    Wind direction: North North West
    Wind Speed: 2.6 m/s

    can someone interprete? is the wind blowing back into Japan?

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  354. Hank, circulation by steam is a two fold explaination. One is by steam driven pumps, injecting coolant which is ideal…

    Second is by steam driven cooling by convection, less than ideal but workable under proper conditions…. This last method relies on wetting the fuel and allowing the steam to rise… removing heat and preventing fuel melt. That’s as simple as I can make it.

    Like

  355. I hope the Japs are able to get enough pumping power on site to flood the boilers. Is there any chance that the condensers can be restarted so it wont have to ventilate everything to athmosphere?

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  357. Sadly, we digress into agendas. Forgetting the mental anguish those affected are feeling locally. It may seem that I analyaze the reports positively with regards to the nuclear events. But I hold alot of skepticism for the news reports too and filter them. I don’t trust the media any more than the skeptics here. I am concerned about reactor 2 right now, but withold judgement for now.

    Show me the data on significant release rates or radiation level increases on site. Then I will say a major nuclear accident impacting the populous now or long term has occurred. I live in the factual world.

    Factually the real horror at the moment is the natural phenomenon that has destroyed an unbeliebable amount of Japan and killed thousands of innocent people. Those that survived are struggling , shelter, food, and fresh water supplies are dwindling…. Never mind the loved ones they may have lost.

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  358. Hank, my bad it’s getting late.. 0.650mpa is 6.5 bar. Does not sound very much at all to me then, a couple of sentrifugal pumps would be able to deliver above that without any problem. But i have only worked with oil boilers, never nuclear so there’s probably more to it than i know.

    So 65 bar is normal operating pressure? Then it sounds to me that its some leeway still, as the denser steam also takes away more heat. but again i might be totally off.

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  359. Now what?
    http://abcnews.go.com/International/japan-earthquake-reactor-fukushima-nuclear-plant-explodes/story?id=13131123#
    “Japan Earthquake: Third Reactor at Fukushima Nuclear Plant Explodes
    Blast Came After IAEA Said Containment Vessels at Fukushima Nuclear Reactors Seem to Be Working
    March 14, 2011
    … a new explosion Tuesday morning at a reactor the Fukushima Daiichi nuclear plant, the Japanese nuclear safety agency reported.
    The blast, which occurred at Unit 2, is the third at the plant since a powerful earthquake struck Japan on Friday….
    The explosion, which occurred at 6:10 a.m., came shortly after the International Atomic Energy Agency had announced that the reactors at the Fukushima Daiichi plant had been shut down. ….”

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  360. New blast reported at damaged Japan nuclear plant

    http://www.marketwatch.com/story/new-blast-reported-at-damaged-japan-nuclear-plant-2011-03-14

    LOS ANGELES (MarketWatch) — Japanese media reported a new explosion heard at the No. 2 reactor of the earthquake-damaged Fukushima Daiichi nuclear power plant early Tuesday morning. Several reports cited government officials as confirming the blast at 6:10 a.m. local time (5:10 p.m. U.S. Eastern time). Officials with the Nuclear and Industrial Safety Agency said the incident may have damaged the reactor’s pressure-suppression system, according to the Kyodo news agency. The plant, operated by Tokyo Electric Power Co. /quotes/comstock/64e!9501 (JP:9501 1,621, 0.00, 0.00%) , has been the focus of widespread concern about a large-scale radiation leak.

    Reportedly damaged the “pressure suppression system” shich apparently is the “inerted drywell (primary containment)” surrounding the reactor vessel proper and includes the “pressure suppression torus” at the base of the reactor.

    http://www.nucleartourist.com/type/bwr.htm

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  361. http://abcnews.go.com/International/japan-earthquake-reactor-fukushima-nuclear-plant-explodes/story?id=13131123&page=2

    “… Officials first became concerned about unit 2 at the plant after pressure began rising in the reactor. Officials from the Tokyo Electric Power Co. told NHK News that the explosion at unit 3 might have damaged unit 2’s cooling system.

    “They’ve had trouble with getting the pumps working, with site power in general… They’ve shipped in extra diesel generators and they may have to do some extra retrofit plumbing,” Morse said.

    … unit 3, which exploded early Monday morning in Japan, reportedly has a leak in its bottom.

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  363. Thanks for catching that — it’s an order of magnitude error error, actually.

    I’ve made some too. Let’s show our work or link to online calculators. We need sanity checks.

    Sounds like it’s getting much worse at the site, if the “hole in the bottom” means the torus is leaking.

    http://www.nytimes.com/2011/03/14/world/asia/japan-fukushima-nuclear-reactor.html?pagewanted=2&src=un&feedurl=http://json8.nytimes.com/pages/world/asia/index.jsonp

    “normally you would just re-establish electricity supply, from the on-site diesel generator or a portable one.” Portable generators have been brought into Fukushima, he said.

    Fukushima was designed by General Electric, as Oyster Creek was around the same time, and the two plants are similar. The problem, he said, was that the hookup is done through electric switching equipment that is in a basement room flooded by the tsunami, he said. “Even though you have generators on site, you have to get the water out of the basement,” he said.

    Another nuclear engineer with long experience in reactors of this type, who now works for a government agency, was emphatic. “To completely stop venting, they’re going to have to put some sort of equipment back in service,” he said. He asked not to be named because his agency had not authorized him to speak.

    The central problem arises from a series of failures…

    Inside the plant, according to industry executives and American experts who received briefings over the weekend, there was deep concern that spent nuclear fuel that was kept in a “cooling pond” inside one of the plants had been exposed and begun letting off potentially deadly gamma radiation.

    Then water levels inside the reactor cores began to fall. While estimates vary, several officials and industry experts said Sunday that the top four to nine feet of the nuclear fuel in the core and control rods appear to have been exposed to the air — a condition that that can quickly lead to melting, and ultimately to full meltdown.

    At 8 p.m., just as Americans were waking up to news of the earthquake, the government declared an emergency, contradicting its earlier reassurances that there were no major problems. But the chief cabinet secretary, Yukio Edano, stressed that there had been no radiation leak.

    But one was coming: Workers inside the reactors saw that levels of coolant water were dropping. They did not know how severely. “The gauges that measure the water level don’t appear to be giving accurate readings,” one American official said.

    What the workers knew by Saturday morning was that cooling systems at a nearby power plant, Fukushima Daini, were also starting to fail, for many of the same reasons. And the pressure in the No. 1 reactor at Fukushima Daiichi was rising so fast that engineers knew they would have to relieve it by letting steam escape.

    Shortly before 4 p.m., camera crews near the Daiichi plant captured what appears to have been an explosion at the No. 1 reactor — apparently caused by a buildup of hydrogen. It was dramatic television but not especially dangerous — except to the workers injured by the force of the blast.

    The explosion was in the outer container, leaving the main reactor vessel unharmed, according to Tokyo Electric’s reports to the International Atomic Energy Agency. (The walls of the outer building blew apart, as they are designed to do, rather than allow a buildup of pressure that could damage the reactor vessel.)

    But the dramatic blast was also a warning sign of what could happen inside the reactor vessel if the core was not cooled. The International Atomic Energy Agency said that “as a countermeasure to limit damage to the reactor core,” Tokyo Electric proposed injecting seawater mixed with boron — which can choke off a nuclear reaction — and it began to do that at 10:20 p.m. Saturday.

    It was a desperation move: The corrosive seawater will essentially disable the 40-year-old plant; the decision to flood the core amounted to a decision to abandon the facility. But even that operation has not been easy.

    To pump in the water, the Japanese have apparently tried used firefighting equipment — hardly the usual procedure. But forcing the seawater inside the containment vessel has been difficult because the pressure in the vessel has become so great.

    One American official likened the process to “trying to pour water into an inflated balloon,” and said that on Sunday it was “not clear how much water they are getting in, or whether they are covering the cores.”

    The problem was compounded because gauges in the reactor seemed to have been damaged in the earthquake or tsunami, making it impossible to know just how much water is in the core.

    And workers at the pumping operation are presumed to be exposed to radiation; several workers, according to Japanese reports, have been treated for radiation poisoning. It is not clear how severe their exposure was….”

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  364. Pingback: Por qué no estoy preocupado por los reactores nucleares de Japó « My Little Posterous

  365. Can’t vouch for this but it’s interesting and seems credible thinking, doesn’t have any news in it:
    http://hotbabysitter.livejournal.com/32121.html

    “… my father works at a nuclear power plant. It’s in southern Georgia …. and is technically a project manager for the plant, not actually a nuclear engineer. Now, obviously, the power plant explosion in Japan is high on the topics of conversation around his workplace. Since he knows that I think his work is really cool and I like hearing about things, he forwarded me and all of his colleagues an email with two highly informative updates on what exactly happened at Fukushima-Daiichi. I’m sure some of y’all already know what’s going on, since y’all are more proactive in looking up what’s going on in the world than me, but if you’re interested in a long, informative update from people in the business, I’m copying it in here ….”

    [excerpts from that (it was prematurely hopeful, written before the 3rd explosion and report of a leak below unit 2, however)-hr]

    “There still is no heat rejection from the pressure suppression pools at any of the reactors so temperatures and pressures are rising and venting is needed. The tsunami destroyed the service water cooling systems. TEPCO is working hard to set up temporary RHR heat exchangers to cool the pools before they get too hot or the seawater levels in the basement areas rise to unacceptable levels.

    At Units 1 and 3, I have confirmed that borated seawater is being injected into the depressurized cores with high pressure fire engine pumps. Both Unit 1 and Unit 3 primary coolant systems are now depressurized at 35-50 psig. Core cooling is with the relatively cold injected borated seawater, but the flooded wet and dry wells are filling and this mode cannot be sustained indefinitely without overflows. So within the next day, TEPCO will need to get some decay heat removal temporary heat exchangers operating to cool the wet well, Then they can go into a stable recirculation mode. Once closed recirculation can be achieved the addition of new flooding seawater can be minimized. But water injection/recirculation will likely continue somewhat like this for weeks.

    It is actually very similar to how we cooled down the damaged/melted Three Mile Island Unit 2 core using the TMI main coolant pumps and steam generators. Of course Fukushima is a BWR and different, but the principle is the same. At TMI this mode continued for several months while core heat decayed. So much of this is like reliving Three Mile Island all over again.

    From various sources I have gathered more information on what actually happened. As often happens, early information can be incorrect, but I think these are correct.

    It seems that all the reactors withstood the earthquake ground motion OK. We do not have a comparison of actual versus design basis accelerations, but even though the motion was probably over the design basis, most safety systems seemed to be functional until the tsunami hit. The tsunami was the big problem.

    It seems that Fukushima design basis tsunami was 6.5 meters, but the actual tsunami was in the 7-8 meter range. These waves washed the diesel fuel system away, submerged the switchyard and destroyed most of the switchgear. This massive damage to the electrical system prevented rapid hookup of auxiliary diesel generators that were relatively quickly brought on site. So only the turbine driven battery controlled RCIC was available to inject water into the reactor vessel until AC power was restored to the HPCI.

    There is no information about the Unit 1 spent fuel pool situation. By now I am sure that TEPCO has the ability to pump water into the pool to maintain water levels. A small fire hose is all that is needed. There is no information available on debris from the explosion or anything else in the pool that is now completely exposed to the environment. Unless heavy debris fell into the pool and damaged spent fuel, this is not a big issue as long as they can keep pool water levels stable, which they should. Given the radiological releases from the primary containment pressure venting, the spent fuel pool releases are negligible.

    Neither is there any information on the spent fuel dry storage cask modules that are at the Fukushima site. The Fukushima Independent Spent Fuel Storage Facility (ISFSF) is in the back of the plant site away from the ocean, so it is hard to tell if it was flooded or not. I suspect that wave water got there, but if it did it was a comparatively nothing event since these are passive cans. I believe there is ~100MTU of spent fuel in their ISFSI. But just being there is an issue in itself. Technically it is better there than in the Unit 1 pool without a roof….”

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  366. We are now almost four days on from the time the earthquake hit (that would be 4.46pm AEST this afternoon, I believe). The reactors were scrammed at the time of the quake, and the daughter product heat output will have been dropping exponentially since then.

    Does anyone know how long external cooling needs to be maintained? I thought I heard something of the order of a week. If so, we should by this time be a fair way along the decay curve for heat output.

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  367. This is a probably credible source, just judging by the authors’ bios at the site. It is not a reassuring piece, it has more numbers and details on the spent fuel pool and the dry cask storage than I’ve seen elsewhere — although still far more questions than answers.

    Barry, if you have a chance, I recommend a look at this and wonder if you can cite or debunk any of it.

    http://dcbureau.org/201103141303/Natural-Resources-News-Service/fission-criticality-in-cooling-ponds-threaten-explosion-at-fukushima.html

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  368. Midnight GMT … just watched a live press conference hosted by Tokyo Electric on NHK news.

    They said that the explosion at Daiichi No 2 (6:14 am Yokyo time) appeared to eminate from “low in the structure”, that they thought the supression pool casing had been breached (accounting for failure to be able to maintain water level ?), that the fuel rods were currently dry, and that measured levels at the plant gates were currently 8217 micro Sv/hr !

    All personell non-essential to the recovery operation had been evacuated.

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  369. Back in the late 60’s early 70’s, the USS Barb SSN-596, a nuclear-powered fas