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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.

By Barry Brook

Barry Brook is an ARC Laureate Fellow and Chair of Environmental Sustainability at the University of Tasmania. He researches global change, ecology and energy.

678 replies on “Discussion Thread – Japanese nuclear reactors and the 11 March 2011 earthquake”

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)

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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.

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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.

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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.

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There are also a few related comments on Open Thread 9, but there seems little point in copying those, or even linking, on this thread.

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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.

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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?

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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.

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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.

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@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.

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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”?

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I’m about to go into Channel 9 TV studios to talk about the nuclear plant/earthquake situation at 5:30pm tonight (AEDT). Will also be on the Ch9 morning show at 8:15am tomorrow (different interview).

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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.

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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.

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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

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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.

No idea how true it is.

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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.

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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.

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“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.

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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!

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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.

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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.”

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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….”

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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.

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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.”

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Just caught Barry on WIN News. It went OK then senior newsman Peter Harvey chimed in with an upbeat assessment ridiculing the Chernobyl comparison. Let’s hope it falls well short of TMI.

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Just saw Barry’s appearance on channel 9. What a cool, level headed, sensible response to questions on the situation. Exceptionally well done.

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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.

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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.”

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NYT puts a name on the quotes:

“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

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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?

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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

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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?

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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.

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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.

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> 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.

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> 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.

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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)

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I missed Barry. Bummer. Turned on the 17:30 news (in Brisbane) and I just got a reference. Ziggy got a good few minutes and spoke well on the performance of the safety systems.

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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.

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My wife, Sonomi, is from Tokyo by the way. For people who’ve been asking me about whether her immediate family are okay — yes, as far as we know everyone is fine, thank goodness.

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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.

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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

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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.

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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…..

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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.

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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:

(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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YouTube content removed Scott, as ‘spam/ scam / commercially deceptive content’.

If it is an explosion at the plant, it’s going to have happened to a secondary or tertiary system, not the reactor containment building.

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The plant owner, TEPCO, reports an explosion at Fukishima with worker injuries, as the Fukishima nuclear accident continues.

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What caused the explosion is the question. I hope it’s not hydrogen gas, because we can all see the implications of that happening…

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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.

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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

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..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.

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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.

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@ 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?

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@esquilax
My thoughts exactly. Modern NPP:s are designed so that even core meltdown can be controlled (to some extent), but why all old NPPs have not been upgraded to better standards is absurd.

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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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@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.

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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.

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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.

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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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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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“World Nuclear Association comms dir says blast due to hydrogen igniting, may not necessarily have caused radiation leakage”

from twitter. Any confirmation?

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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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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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@Barry
Let’s hope your hunch is right. But I am still worried. I regard our regulatory agency STUK highly.They are not anti-nuclear crazies and know what they are talking about.

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I suspect the Hydrogen explosion is tied to attempting to vent the containment using Reactor Building Ventilation. Possibly a duct rupture.

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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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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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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.

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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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CNN confirming venting of containment was in progress prior to explosion… Confirms my idea that it was a hydrogen explosion due to venting that destroyed the reactor building.

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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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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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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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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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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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Assuming the steel pressure vessel is intact, you’ve still got to dump residual heat from the core for a while yet. Are there still systems available for this after the explosion?

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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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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.

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I have experience with GE BWRs, emergency operating and severe accident management procedures. Though not site specific to there, they are likely very similar.

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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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