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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”

Some ideas : I am a bit concerned with the fact that the salt concentration will increase as cooling with sea water continues. Water evaporates but salt will get more and more concentrated. Boron addition will also lead to forming crystals at the high temperatures existing in the reactor. This could further limit the flowrate of the cooling media. Demin water should be brought to the site by tanker (ship) and send to the reactor using the power plant primary loop using the feedwater pumps (flooding the the turbine, condenser).
This could maybee provide a more efficient cooling system.

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Cy I don’t think the US military are going to do anything new, let alone something the Japanese haven’t been doing.

I wouldn’t be surprised if they were asking the US military for equipment assistance if anything. Either that or assistance in filling up that spent fuel pond in reactor 3.

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Great discussion. I have been following it since the start. Some really great and thought provoking reading that has greatly helped me “lean” how bwr work over the last 5 days.

I’m a young nuclear professional who started working at a pwr station so thats what im familiar with. We have done mods to our station that would have HUGELY helped this situation. For one the Passive Auto-catalytic Re-combiners would have helped these guys quite a bit.

Anyway I have a question, please bear in mind that I am asking this in general and not considering unit specific problems…until mentioned otherwise. Please correct if I am horribly wrong along the way.

So they are cooling the cores using diesel drive fire pumps to inject sea water into the reactor vessels. If the cores are uncovered…that means either steam above the vessel or a break in the reactor vessel below the fuel lines preventing filling of the vessel.

From what I understand there isn’t a whole in of the problem units. So its not that. So it can only be steam in the RPV…well steam and other non condensibles.

So my question is How is that steam leaving the RPV and being condensed or ected from the system so that heat can leave the reactor and therefore the core can be cooled

Do they direct it strait from the rpv to the containment and then into the suppression pool?

Then my next question is…if they are not doing the above..how are they actually cooling the core by “injecting sea water”. All that water has to go somewhere as steam or water. Where is it going to.?

I have another follow up question to this so I’m looking forward to your response. Regards.

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Re water loss from the spent-rod cooling pools:

These things are built to keep the rods many meters below the open surface, so while ‘sloshing’ under the 9.0 displacement must have happened and shortened the boil-off interval, it also seems likely that the pools may have been compromized and drained into the lower parts of the reactor buildings, with unknown effects on the electrical and mechanical components there.

Those major gas explosions may well have emptied the pools also. In the video I see a huge mass of liquid-phase water cascading down, after being thrown aloft by a weapons-grade blast effect.

I’m wondering if the spent rods in the blasted buildings may have been thrown out of the pools, assuming the pools survived. It’s clear now that the pictures being shown Mar 12-15 were several days old, and likely selected for angles that didn’t show lower walls that were demolished, beneath the surviving penthouse frames.

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Re: the SFPs

Anyone have any theories on how the situation in the spent fuel pools at #4 occured in the first place? Some alarms must have gone off once the water level started to fall? It seems to me that they should have had enough time to hook up some auxiliary pumps once the lights started to blink…?

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Rice, although #4 was in cold shut-down mode, it’s SFP contained rods more recently in use, and therefore radiologically and thermally hotter than 5&6 SFP’s. If as reported there are 8 sets of fuel rods in SFP#4, that may represent greater storage mass and density, as well as the freshest set.

In addition, 4 was adjacent to the H2 blast wave from #3. It appears that reactors 1-4 are paired on/in larger buildings, and could share ducting and passageways that would internally contain, communicate, even locally focus the supersonic blast shockwave that can be seen dissipating for >100M outside, even in low res.

We’ve been hearing about the double-whammy of 9.0 EQ and a huge tsunami hydro-hammer-flood. But the atmospheric over-pressures from the multiple H2 explosions means it’s more like quadrupple consecutive shocks, each individually above the DBA (design basis accident) parameters.

Those DBA assumptions didn’t allow for simultaneous loss of emergency aux power and grid power, reactor overheat-overpressure followed by explosive H2 shock-waves.

Given the sea-water flooding and loss of containment, large scale radio-contamination of the near shore seems inevitable, a reasonable choice to keep the reactor site workable

I hesitate to link cable news, but this 3/15 in-depth CNBC piece contained more information in one place than I’ve encountered, although events continue to overtake yesterday’s news.
http://www.americablog.com/2011/03/maddow-heres-what-nuclear-meltdown.html

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Can anyone explain the purpose of dropping water from a helicpter if the primary containment structure and the reactor vessel itself is still intact? I think it would provide no cooling benefit unless the reactor core is exposed…

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The workers in japan trying to manage the issues at the nuclear power plant are a testimate to the nuclear industry.

Rather than providing a negative for the nuclear industry, the impacts that the nuclear facility has withstood and the response of the Japanese nuclear workers whould be a sign of how safe nuclear power is.

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D714: Water from helo-buckets and fire-hoses is aimed at the #3 spent fuel pool. That pool, and the #4 SFP are near the top of reactor buildings that are so shattered (just look at the pics) that there is some hope water will splash down into exposed pools, which have cooked dry enough to burn and emit smoke laced with iodine and cesium. I believe that #3 reactor, thought to have compromised containment, is part of the MOX (plutonium-uranium) pilot program. So getting that SFP under control so work on reducing Pu reactor leakage there can commence is a priority. The SFP’s in 1-4 are thought to be the greatest source of leaking radiation at this time, with the potential to get much worse in magnitude and variety of particles release. Without external power, SFP’s in 5 & 6 are said to have rising temperatures, falling water levels.

If you go to the JAIF site linked above, and look at the status report tables, you’ll see that reactor containment is thought damaged by the TEPCO operator on #2 & #3.

Ryan, anyone who is sees multiple reactors and SFP’s damaged to a degree that makes work to contain the leaks almost impossibly dangerous, and guarantees permanent quarantine of property beyond the perimeter of the plant, that somehow proves the general safety of nuclear power? That person is not being careful about their own credibility.

Putting MOX fuel in an old reactor, designing them with the uncontained SFP’s so close to the reactor, letting these roof-top SFP’s become densely packed with decades worth of high-level waste, the lack of gravity fed emergency cooling water: These were not comforting signs of a careful industry, even before the earthquake exposed them as dangerous practices.

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@WW,

That last post was a test.

I previously attempted to post the extact opposite of that argument on this wall and it was taken down by the site moderator.

I wanted to test whether comments were being taken down merely because they were not technical discussion about what was occurring, or because they did not support Mr Brooks agenda on Nuclear Power.

Seems like the later was correct, and confirmed my suspicions about Mr Brooks.

MODERATOR
Comments, which are personal opinions and attack people in a negative fashion are a violation of the Commenting Rules and are deleted.

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Ryan,
given the inflammatory and motive attacking nature of your post here, I can only assume Barry removed your post because it was either ‘playing the man and not the ball’ or was actually full of [ad hom deleted] misinformation. When Barry is getting a million hits a week, he doesn’t have time to suffer [ad hom deleted]

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////The workers in japan trying to manage the issues at the nuclear power plant are a testimate to the nuclear industry.

Rather than providing a negative for the nuclear industry, the impacts that the nuclear facility has withstood and the response of the Japanese nuclear workers whould be a sign of how safe nuclear power is.////

If you posted the reverse of this you’re actually attacking PEOPLE who are potentially giving their lives to prevent a disaster. You’re also attacking a nuclear technology that is outdated. You obviously haven’t heard that these Japanese reactors are older Gen2 reactors, and we now have exponentially safer Gen3 reactors with “Neutron leak” built into the fuel rods so that if they overheat they expand, leak neutrons, and the reaction shuts down. And this is as a completely last resort because:
* Homer Simpson has fallen asleep at the wheel,
* aliens have invaded and shut down the cooling systems (because Australia wouldn’t be building them anywhere near Tsunami prone disasters)

So, basically, if you were making generalisations about the whole UNIVERSE of nuclear power from these old reactors, you were being foolish. But if you were attacking the workers involved — some of whom might get radiation poisoning to prevent this disaster — then you are a [ad hom deleted]

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Eclipse, fair enough assumption given that I wrote that it was “exact opposite” but incorrect.

The post also praised the workers, but stated that theey should not be placed in such a horrible position of having to put their own health at risk to save the health of others, and that this is the intractable issue with nuclear when things go wrong.

It did not play the man, nor contain misinformation – but rather an oppinion baseed upon fact which was reasonable and fair to make. Giving the moderator the benefit of the doubt, I though this may have been because it was not a technical post. But given that my last pro-nuclear post was posted and was non-technical it looks like this site has an agenda of stifling comments which are anti nuclear.

Also my comments were not imflammatory or attacking, but simply a statement that only comments which support Mr Brooks agenda are posted. Interestlingly the two responses I get were immediately “playing the man”, calling me a “fool” and a “heatless bastard”. Interesting indeed.

MODERATOR
The ad homs have now been deleted. Apologies.

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“MODERATOR
Comments, which are personal opinions and attack people in a negative fashion are a violation of the Commenting Rules and are deleted”

This was posted on my comment above.

1. The comment that was removed contained no reference or attack on any people as the moderator should well know. But by posting this, and not my actual comment, the moderator has effectively insinuated to others otherwise. I hope such was not intentional.

2. The two last posts called me a fool and a heartless bastard, in accordance with the apparent moderator’s comment policy I await them to be removed.

MODERATOR
Please re-post your original “in contention” post, giving appropriate references to your
personal analysis re the risk to health of the workers the workers on site. You are correct regarding the inappropriate adjectives used toward you and they will be edited. I apologise .Please understand that I am only human and have been wading through thousands of posts for the last 6 days with hardly any sleep.

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Get some sleep Barry. You’ve been hard at it — all over the blog, all over the media, all over TV and blogs and interviews. It seems like every time I turn to a different news source another TV interview with you crops up!

Go for a walk and have some fun with the family, watch a funny movie with your wife, you’ve earned it!

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Ms. Perps, on 19 March 2011 at 2:10 PM said:

@ Ryan 234
You said :
“The post also praised the workers, but stated that theey should not be placed in such a horrible position of having to put their own health at risk to save the health of others, and that this is the intractable issue with nuclear when things go wrong.”
Perhaps it was your personal opinion that the workers were in fact putting their own health at risk (I assume without relevant authoratative references)that got your post removed.
If I had my husband/son/brother etc working there I would not want to read your doomsday scenario. Remember there are many Japanese residents using this site for real information not conjecture.
SORRY – POSTED THIS BEFORE ON THE WRONG THREAD.

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A friend of mine had an idea I would like to put out there to people who know more about this issue.

The steam that comes off from cooling; I am guessing; carries a fair bit of toxicity.

If ceramic glazes, which have a curing temperature right around the temperature of these damaged reactors, are dropped enmasse on the reactors; could that form a good plug to then cement over?

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[Comment deleted. Please re-post on the correct thread – Fukushima Open Thread. We do not have the ability to move comments between threads.]

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There is a lot of confusion as to what levels of radiation and exposure are not safe. The following link clearly explains how radiation dose rates and exposure limits are determined by epidemiology studies to protect the public and nuclear energy workers in Canada. The risk assessment is based on national data plus inputs from international groups of experts in radiation protection:
http://nuclearsafety.gc.ca/pubs_catalogue/uploads/March-17-2011-INFO-0812-Setting-Radiation-Requirements-on-the-Basis-of-Sound-Science-The-Role-of-Epidemiology_e.pdf . March 2011

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Is it possible that the latest release of steam ,that does not appear to have caused a radioactivity spike is one of the pressure relief valves on the cooling water pipework, or the core injection pipework?

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The Safety Culture of the nuclear industry in Japan has also suffered, as suggested by the following article:
Japan Nuclear Disaster Caps Decades of Faked Reports, Accidents
http://www.bloomberg.com/news/2011-03-17/japan-s-nuclear-disaster-caps-decades-of-faked-safety-reports-accidents.html .

“… Tanaka says the vessel was damaged in the production process. He says he knows because he orchestrated the cover-up. When he brought his accusations to the government more than a decade later, he was ignored, he says.

In 1990, Tanaka wrote a book called “Why Nuclear Power Is Dangerous” that detailed his experiences. “{out of print but soon to be republished}.

“Tokyo Electric in 2002 admitted it had falsified repair reports at nuclear plants for more than two decades. Chairman Hiroshi Araki and President Nobuyama Minami resigned to take responsibility for hundreds of occasions in which the company had submitted false data to the regulator. …”

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It would be useful to come back to this early topic, and sum up what was believed at the time and what’s changed — for a “lessons learned” approach.

A “who could have believed …” summary might help too.

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