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The Fukushima Question: How close did Japan really get to a widespread nuclear disaster?

I think The Breakthrough Institute guys, led by Michael Shellenberger and Ted Nordhaus, are doing great working in environmental policy and thought leadership, which is why I was delighted to become a 2012 Senior Fellow. Below I reproduce an important article published today in, on Fukushima and its ensuing hyperventilation. Much of the post-accident speculation was constrained only by people’s imagination (which can be pretty wide ranging), and utterly failed to resolve the fact that RISK is probability X impact. Instead, anti-nuclear types typically choose a huge, speculative impact, and then try to attach a large probability (often near certainty) to it. For truly catastrophic outcomes, the product of the many low-probability events required for initiation make the mathematical risk a vanishingly small one.

How close did Japan really get to a widespread nuclear disaster?

By Ted Nordhaus and Michael Shellenberger

Posted on Slate Thursday, March 1, 2012, at 4:55 PM ET

With an eye to the first anniversary of the tsunami that killed 20,000 people and caused a partial meltdown at the Fukushima power plant in Japan, a recently formed nongovernmental organization called Rebuild Japan released a report earlier this week on the nuclear incident to alarming media coverage.

The crippled Fukushima Daiichi nuclear power plant in Okuma, Fukushima prefecture as of February 2012. Issei Kato/Getty Images

Japan Weighed Evacuating Tokyo in Nuclear Crisis,” screamed the New York Times headline, above an article by Martin Fackler that claimed, “Japan teetered on the edge of an even larger nuclear crisis than the one that engulfed the Fukushima Daiichi Nuclear Power Plant.”

The larger crisis was a worst-case scenario imagined by Japanese government officials dealing with the situation. If workers at the Fukushima Daiichi plant were evacuated, Fackler writes, some worried “[t]his would have allowed the plant to spiral out of control, releasing even larger amounts of radioactive material into the atmosphere that would in turn force the evacuation of other nearby nuclear plants, causing further meltdowns.”

Fackler quotes former newspaper editor and founder of Rebuild Japan Yoichi Funabashi as saying, “We barely avoided the worst-case scenario, though the public didn’t know it at the time.”

To say that Japan “barely avoided” what another top official called a “demonic chain reaction” of plant meltdowns and the evacuation of Tokyo is to make an extraordinary claim. One shudders at the thought of the hardship, suffering, and accidents that would almost certainly have resulted from any attempt to evacuate a metropolitan area of 30 million people. The Rebuild Japan report has not yet been released to the public, but there is reason to doubt that Japan was anywhere close to executing this nightmare contingency plan.

The same day the New York Times published its story, PBS broadcast a Frontline documentary about the Fukushima meltdown that invites a somewhat different interpretation. In an interview conducted for that program, then-Prime Minister Naoto Kan suggests that the fear of cascading plant failures was nothing more than panicked speculation among some of his advisers. “I asked many associates to make forecasts,” Kan explained to PBS, “and one such forecast was a worst-case scenario. But that scenario was just something that was possible, it didn’t mean that it seemed likely to happen.”

The authors of the Rebuild Japan report also spoke with Kan, along with about 300 others. According to the Times, these interviews turned up evidence that the Tokyo Electric Power Company was looking to abandon the teetering power plant, a plan that would have significantly worsened the crisis.

But was this ever really going to happen? Kan told PBS that his Cabinet members had said Tepco “wanted to withdraw,” but adds that the company’s CEO “would not say clearly [to Kan] that they wanted to withdraw, or that they wouldn’t withdraw.” The producer of the Frontline documentary, Dan Edge, said in an interview posted to the PBS website that the Fukushima workers he interviewed said they were told they on the evening of March 14 that there would be a complete evacuation, but then told the next morning that there would not be.

All this suggests there was significant confusion and indecision, and there is no question that what happened at Fukushima demands critical investigation and accountability. Whether or not Tepco mismanaged Fukushima after the tsunami hit, there is evidence that company officials had delayed upgrading the plant ahead of time and ignored the risk of a tsunami large enough to breech the seawall.

The Rebuild Japan report seems, on its face, to have been produced by a highly credible team of “30 university professors, lawyers and journalists.” But even a seemingly legitimate study deserves a skeptical eye. Yet Fackler and the Times chose not to quote a single independent expert on nuclear energy besides Rebuild Japan’s Funabashi. It should have been a red flag that Rebuild Japan gave its report to journalists a full week before releasing it to the public, which prevented outside experts from evaluating its claims. Another hint that the report merited a contrary opinion was the fact that it excluded any account from Tepco executives, who refused to be interviewed by Rebuild Japan investigators.

There’s no question that the findings from the Rebuild Japan study merited coverage, but the Times might have shown more awareness of the fallacy of the worst-case scenario. “In any field of endeavor,” wrote physicist Bernard Cohen in his classic 1990 study, The Nuclear Energy Option, “it is easy to concoct a possible accident scenario that is worse than anything that has been previously proposed.” Cohen goes on to spin a scenario of a gasoline spill resulting in out-of-control fires, a disease epidemic, and, eventually, nuclear war.

Cohen concludes his fantastical thought experiment by saying, “I have frequently been told that the probability doesn’t matter—the very fact that such an accident is possible makes nuclear power unacceptable. According to that way of thinking, we have shown that the use of gasoline is not acceptable, and almost any human activity can similarly be shown to be unacceptable. If probability didn’t matter, we would all die tomorrow from any one of thousands of dangers we live with constantly.”

It was perfectly reasonable for the Japanese authorities to have imagined and considered the very worst possible course of events in the aftermath of Fukushima meltdown. But it’s a mistake to oversell the risks of such a scenario in hindsight. Yes, things could have turned out much worse—just as they could have turned out much better. As the Times and the rest of the news media cover the anniversary of the tsunami, they would do well to keep Cohen’s warning in mind.

Ted Norhaus and Michael Shellenberger


Barry Brook: For those who are interested, here is the full relevant section from Bernard Cohen’s 1990 book:

The Worst Possible Accident

One subject we have not discussed here is the “worst possible nuclear accident,” because there is no such thing. In any field of endeavor, it is easy to concoct a possible accident scenario that is worse than anything that has been previously proposed, although it will be of lower probability. One can imagine a gasoline spill causing a fire that would wipe out a whole city, killing most of its inhabitants. It might require a lot of improbable circumstances combining together, like water lines being frozen to prevent effective fire fighting, a traffic jam aggravated by street construction or traffic accidents limiting access to fire fighters, some substandard gas lines which the heat from the fire caused to leak, a high wind frequently shifting to spread the fire in all directions, a strong atmospheric temperature inversion after the whole city has become engulfed in flame to keep the smoke close to the ground, a lot of bridges and tunnels closed for various reasons, eliminating escape routes, some errors in advising the public, and so forth. Each of these situations is improbable, so a combination of many of them occurring in sequence is highly improbable, but it is certainly not impossible.

If anyone thinks that is the worst possible consequence of a gasoline spill, consider the possibility of the fire being spread by glowing embers to other cities which were left without protection because their firefighters were off assisting the first city; or of a disease epidemic spawned by unsanitary conditions left by the conflagration spreading over the country; or of communications foul-ups and misunderstandings caused by the fire leading to an exchange of nuclear weapon strikes. There is virtually no limit to the damage that is possible from a gasoline spill. But as the damage envisioned increases, the number of improbable circumstances required increases, so the probability for the eventuality becomes smaller and smaller. There is no such thing as the “worst possible accident,” and any consideration of what terrible accidents are possible without simultaneously considering their low probability is a ridiculous exercise that can lead to completely deceptive conclusions.

The same reasoning applies to nuclear reactor accidents. Situations causing any number of deaths are possible, but the greater the consequences, the lower is the probability. The worst accident the RSS considered would cause about 50,000 deaths, with a probability of one occurrence in a billion years of reactor operation. A person’s risk of being a victim of such an accident is 20,000 times less than the risk of being killed by lightning, and 1,000 times less than the risk of death from an airplane crashing into his or her house.7

But this once-in-a-billion-year accident is practically the only nuclear reactor accident ever discussed in the media. When it is discussed, its probability is hardly ever mentioned, and many people, including Helen Caldicott, who wrote a book on the subject, imply that it’s the consequence of an average meltdown rather than of 1 out of 100,000 meltdowns. I have frequently been told that the probability doesn’t matter — the very fact that such an accident is possible makes nuclear power unacceptable. According to that way of thinking, we have shown that the use of gasoline is not acceptable, and almost any human activity can similarly be shown to be unacceptable. If probability didn’t matter, we would all die tomorrow from any one of thousands of dangers we live with constantly.

This whole chapter (and the book) is superb:

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.

79 replies on “The Fukushima Question: How close did Japan really get to a widespread nuclear disaster?”

The question for me is: was there *really* ever any chance of Tokyo needing to be evacuated? Perhaps, Kan et al did envisage a situation in that would happen, but was that just a spur of the moment panic? Or was it based on any kind of actual evidence and reasoning? I’d be very interested in the actual opinion of nuclear scientists and engineers, not the wild hypothesising of politicians.


I can imagine a meeting where Kan said to his nuclear advisors (it’s human nature to think like this): “Okay, what is the *worst* possible situation you can envisage? Let’s establish that and then work backwards to make sure we’ve got this situation covered.” Indeed, that’s probably the strategic planning pathway I would have taken if in that situation. Then of course, we get anti-nuclear groups and general fearmongers taking those scenarios are reporting them as likely, or a ‘near miss’. When you think about it, it’s almost inevitable, especially since this sells lots of newspapers.


Deleted: Due to numerous unsupported assertions this comment was excised – extraordinary claims require extraordinary evidence, and you provide zero references to back up your claims. Try again and comment properly, or dump this stream of conciousness on other, unmoderated sites. ED.


“Minister Naoto Kan suggests that the fear of cascading plant failures was nothing more than panicked speculation among some of his advisers. “I asked many associates to make forecasts,” Kan explained to PBS, “and one such forecast was a worst-case scenario. But that scenario was just something that was possible, it didn’t mean that it seemed likely to happen.”

And in all the reporting of this report, and a much earlier story on how PM Kan imagined an empty Tokyo, evacuated because of the disaster – none of the Japanese Media, as far as I can see, have focused much on his likelihood statement. That said, the radiation hysteria over here is so great that such statements, like that reported in this Japan Times piece:

“The scenario is total fiction, but we thought about what we might have had to do to prevent an escalation,” Kondo said.

…get forgotten very quickly.



DV82XL said it best at:

“We have been deceived into believing that all radiation is bad because of policy reliance on the “linear no-threshold” theory, or LNT, which states that if large amounts of something cause death or sickness, fractional amounts of the same thing cause proportional amounts of death or sickness. If the LNT were applied to falling as it is to radiation, we might note that 100 percent of those falling onto concrete from 100 feet are killed, but only 50 percent of those falling from 50 feet die. With these data we would linearly extrapolate to say that 10 percent falling from 10 feet and one percent of those falling from one foot would die. Armed with this “linear no-threshold falling theory,” we could confidently assert that jumping rope should be banned on all school playgrounds since statistically anyone making 100 one-foot jumps would die.”
S. M. J. Mortazavi1 and P. A. Karam2
“Based on the findings obtained by studies on the health effect of high levels of natural radiation in Ramsar, as well as other HLNRAs, no consistent detrimental effect has been detected so far. ”

If I lived at Fukushima, and my house had not been damaged by the tsunami, I would not evacuate.  The radiation from the reactor has not exceeded natural background radiation in many inhabited places on Earth.  

book:  “Power to Save the World; The Truth About Nuclear Energy” by Gwyneth Cravens, 2007   Gwyneth Cravens is a former anti-nuclear activist.

Page 77:   Natural gas contains radon, a radioactive gas.

Page 98:   There is a table of millirems per year from the
background in a list of inhabited places.   
Chernobyl:  490 millirem/year
Guarapari, Brazil:  3700 millirem/year   [=3.7 rem]
Tamil Nadu, India:  5300 millirem/year    [=5.3 rem]
Ramsar, Iran:  8900 to 13200 millirem/year   [=8.9 to 13.2 rem]
All are natural except for Chernobyl.

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:

The Average American gets 361 millirems/year.   Smokers add 280 millirems/year from lead210.   Radon accounts for 200 mrem/year.


There IS a threshold, and it is around 10 or 20 rems/year, which is 100 or 200 msv/year. Fukushima was evacuated because of bureaucratic over-reaction, not because of radiation. What should have been done: The reactor should have been left in operation because it could have continued to cool itself. It was the automatic scram that caused the problem.


One of the things that has been brought home to us, once again, is that nuclear technology is an extremely misunderstood technology to all but a small group of professionals. People do not understand the basics of reactor operation, the effects of ionizing radiation on the body, the effect of dose rates, bio-accumulation, the difficulty of responsibly storing spent fuel, or anything that is actually relevant to the discussion. Yet all things nuclear appear to be a hobby-horse of the popular media. Everyone likes to talk about Fukushima, everyone has something to say about, but almost no one is qualified to talk about it. Most of the popular media articles were about the Daiichi reactors, while no one died of radiation, and there was very little attention to the natural disaster that killed almost 20,000 people. Some articles mentioned the 20,000 death toll from the earthquake and tsunami in the same breath as the nuclear meltdowns, making it appear as if the reactors had killed 20,000 (!). The result is journalists and bloggers doing a lot of damage, keeping the circle of ignorance intact, and it has now become a holy gospel. My respect for the general media has taken another blow, seeing again how journalists generally don’t care about writing representatively, professionally, or unambiguously. It’s easy to scream “radiation” and “Chernobyl” but it requires time, and the listener’s attention and sincere interest, to explain the facts, and to think about the alternative to nuclear, which is fossil fuel, since wind and solar are not there most of the time so can’t power our countries. Mark Lynas’ article I still think is excellent for a perspective:

Also I’d like to refer to an article by one very cranky, unpolite but totally correct, intelligent and factual person:

Clearly as long as we use fossil fuels, especially coal, for generating our electricity, we don’t have the luxury of choice to reject nuclear power.

At the same time it is obvious that Fukushima Daiichi had insufficient design basis protection. Stress-tests have been conducted for nuclear plants around the world to assess the design basis of other nuclear plants, with a particular focus to flooding and tsunamis. I note however that all newer Japanese nuclear plants, did not have core damage or radiation release. Also many plants that are deep inland, or on shores that have no geological driver for tsunamis (like here in the Netherlands) would not need 15 meter tsunami protection. With that in mind, we must take the lessons of Fukushima into current and future plants. These lessons are straightforward. There is nothing magical, residual risk about the accident, it had 6 meter tsunami protection and a 15 meter tsunami came rushing over it, flooding all electrical infrastructure (which was not water proof class either).

These are two important sides of the medal that we must communicate: the perspective, but also the lessons that we have learnt and must incorporate in existing and future nuclear plants (and that it will in many cases, especially newer reactors, turn out to be a non-issue)

It’s very important also that people get familiar with the basics. We won’t convince anyone that doesn’t know the difference between a nuclear criticality sustained chain reaction and decay heat generation.


Have been thinking about the various claims that Japan would become uninhabitable, Tokyo would need to be evacuated etc. So far, I can’t find any credible evidence that there was ever any danger of either of these being a result of Fukushima.

I found myself thinking back to comparisons between Fukushima and Chernobyl in the early days of the event, and the effects of Chernobyl being held up as a metric for what would be the ‘worst case’ scenario for the effects of Fukushima. With this in mind, I found myself looking at the permanent exclusion zone around Chernobyl: – Indeed, sizeable, but pretty much the same land area as the current Fukushima exlcusion zone (and not anywhere near the size of the whole of Japan).

But then I remembered back to this article by Mark Lynas – – it seems that a ‘worst-case’ scenario, with full meltdowns and the wind blowing towards Tokyo, would have resulted in a dose of 3mSv – high, but not warranting a full evacuation.

(Apologies for the rushed state of this comment)


I wouldn’t say 3 mSv is a high dose. Natural background radiation varies between 1 and 300 mSv/year, with no observed increase in cancer risk. 3 mSv is about the additional dose a Tokyo resident would receive if he or she moved to Denver:,,20410979,00.html

Except of course that he or she would then receive such a dose every year, so it is a much bigger dose.

I haven’t heard any politician talking about evacuating Denver, even though 600,000 people live there.

Though, from a equal risk perspective, Tokyo should have been evacuated a long time ago. The pollution there is orders of magnitude more dangerous in cancer risk than the 20 mSv Fukushima evacuation limit. 13 million people live in Tokyo city. 20 million in the Tokyo area. Why hasn’t Tokyo been evacuated yet?


Before I can make a comment, what is the percent of types of radiation, power plants do not put out the same mix of radiation type that is natural and some meters do not read alpha particles which I believe is a high mix in Japan, that is OK if external but is about the worse for intake through air or food.


I’ll be a little contrarian here…it is not just dose delivered via background radiation. It’s also accumulated radionuclides of Iodine and cesium (both isotopes) and what ever else got out that can bio-accumulate. This is a real danger and why its’ GOOD that the gov’t is attempting to clean up some very strong hotspots that are measured in dosages of mSv per *hour*.

Secondly, the evacuation was a smart thing to do. The danger of excessive dosages caused by radionuclides was totally unpredictable as the breaching of containment was totally unknown. You had 3 melting nuclear power plants you don’t think it was correct to evacuate? This is not serious. It’s exactly what you do. The continued evacuation, however, is what should be questioned.


The explanations of the LNT were all excellent, BTW. These are actually excellent sound bites for the news media and the general pubic.

I think we should examine what TEPCO should of done to prevent this from happening. Maybe it’s not with the thread, but it’s worth talking about…and publicizing it.


What, people are still posting that Ramsar notion and the steel reinforcing rod notion, without mentioning the published refutations?

I guess others besides me gave up chasing down the citations.
You do need a good reference librarian or indexer here, else the talking points will be repeated in every thread and drive out information.

Well, the interesting thing about the one-year-later news was the concern about a possible cascading failure if Fukushima had been a severe enough accident to make _other_ nuclear and fuel power plants shut down due to spreading contamination.

That didn’t happen.

Could it?

Another Carrington event would shut down the electrical grid just as effectively and for at least as long as the scenario they were worried about — and over far more of the planet.

12 percent chance. Do we feel lucky?


“For truly catastrophic outcomes, both numbers are very small, and multiplied, vanishingly so.”

Not sure this makes sense. If the outcome being considered is catastrophic, wouldn’t the impact be large by definition. Of course, such events might be nearly impossible and so the actual risk is still low.

Ed: you are right, it was expressed poorly – I’ve edited the original sentence to make it clearer what I meant.


The Cohen book cited has an excellent discussion about how Cohen himself evaluated scientific information. This starts on page 4. Eg:

“The purpose of this book is to provide this information. Most of it is scientific, obtained from sources that are generally accepted in the scientific community. Some readers may be surprised to learn that nearly all the important facts on these issues are generally accepted (within a degree of uncertainty small enough for the differences of opinion to be of no concern to the public). In the past, the media has often given the impression that there are large and important areas of disagreement within the scientific community on these matters. Actually, in spite of such attempts to dramatize it, long-standing controversy is rather rare in science. This is not to say that different scientists don’t initially have different ideas on an issue, but rather that there are universally accepted ways of settling disagreements, so they don’t persist for long”

He respected scientists, and the premier institutions of science, i.e. the National Academy.

He describes the “basic instrument for scientific communication”, i.e. the scientific literature. “The whole system is set up to maximize exchange of information and give a full airing of the facts”. Since “most people would not consider the scientific literature to be interesting reading”, and because some “scientific questions have an impact on public policy”, he says, “The National Academy of Sciences and similar national and international agencies assemble committees of distinguished scientists specializing in the field to develop and document a consensus”. “The committees’ conclusions are generally accepted by scientists and government agencies all over the world”. “This ability to rapidly resolve controversy has been one of the most important elements in the great success of science, a success that during this century has increased our life expectancy by 25 years, and improved our standard of living immeasurably”.

People who consistently attack the National Academy of Sciences independent expert panel reviews of how dangerous radiation is, i.e. the BEIR panels, who say the NAS is stupid and/or corrupt, should read Cohen, especially his remarks on the BEIR panel which start on page 61. See his online Chapter 5.

On whether the general public ought to accept the conclusions of the NAS or whether they should question the findings because the NAS is too stupid or corrupt to produce a panel of “objective experts”, Cohen emphatically came down on the side of accepting what the NAS says.

“The NAS is a nonprofit organization chartered…. to further knowledge and advise the government. It is composed of about a thousand of our nation’s most distinguished researchers from all branches of science. It appointed the BEIR Committee and reviewed its work. The BEIR committee itself was composed of about 21 American scientists well recognized in the scientific community as experts in radiation biology; 13 of them were university professors, with lifelong job security guaranteed by academic tenure…. To believe that such highly reputable scientists conspired to practice deceit seems absurd…. But above all, they are human beings who have chosen careers in a field dedicated to protection of the health of their fellow human beings; in fact many of them are M.D.’s who have foregone financially lucrative careers in medical practice to become research scientists. To believe that nearly all of these scientists were somehow involved in a sinister plot to deceive the public challenges the imagination”.

Of course, Cohen at that time was defending the position that radiation was not as dangerous as types like Sternglas were saying. Sternglas says radiation at low levels is far more dangerous than the LNT model suggests, and he and others had at that time influenced many in the general population. (The Nuclear Energy Option was first published in 1990). That debate is largely over.

Many of the online nuclear advocates of today tell us the BEIR studies have been discredited, or that the BEIR committee was stupid or corrupt, or that they simply rejected all studies that question LNT, or that they had and have no evidence to put LNT forward as a model describing what happens at low levels of exposure to radiation, AND they tell us they want us to read Cohen’s online book to get some information they want to cherry pick out of it.

I suggest people should read that book. I did, and I asked a prominent pro nuclear advocate how he could possibly attack the NAS as incompetent and corrupt while listing Cohen as one of his “heroes”. “Things have changed”, he wrote. “Things are much more polarized now”. He didn’t say Cohen was mistaken about what the NAS is. If Cohen is that wrong about what the NAS is, it would bring into question what he himself says is his primary source of information on all nuclear matters. Pro nuclear advocates who attack science would find Cohen lined up with me.

It is not necessary to reject the findings of the BEIR panel in order to question public policy that claims to be based on their findings.


Anti nukes should be asked to compare the odds of a probable catastrophe civilization blithely accepts, i.e. climate change, to the odds of whatever could have happened at Fukushima. John Schellnhuber, in this keynote speech delivered at the 4 degrees conference held in the UK, discussed risk of a magnitude the anti nuclear types refuse to face.

He pointed to the recent assessment by Ramanathan and Feng indicating that if civilization stopped all further emissions of CO2 immediately the “2 degrees” target so many seem to believe is still possible to achieve is nevertheless as of now likely to be exceeded. That’s if we did not allow one more molecule of CO2 to enter the atmosphere.

He described how unlikely it ever was that 2 degrees was “safe”. Eg:

“So you see the 2 degrees target looks pretty OK. Its a compromise. So of course we will lose all the coral reefs, if we go up to 2 degrees, or most of them, but who needs coral reefs anyway…. But we will at least save the Greenland ice sheet… and so in the end this is a good political compromise. But if you look at the recent work published in PNAS this year [ he mentioned that “ten thousands of studies that have gone into that work” which clearly indicated 2 degrees is actually a borderline between dangerous and extremely dangerous change ]. This is the stark evidence that 2 degrees is clearly not a very good line, but we are talking at this conference of going even beyond 2 degrees.”

Having predicted there is no way now to avoid what civilization is pretending are acceptable catastrophes such as the death of corals worldwide including the Great Barrier Reef, Schellnhuber discussed how climate scientists advising policy makers describe scenarios in terms of probabilities. Discussing the odds some say still exist he summed up the risk as:

“…if we want to have a 75% chance of holding the 2 degrees line.” He then pointed out this is preposterous compared to what is at stake. I.e., he said: “Which is by the way not a brilliant chance. So if you would do that in a calculation involving nuclear power plants, probably most people would be very uncomfortable if they would live next to a plant that had a 25% chance of blowing up. But, its only the planet that we are talking about, so no problem.”

On nuclear power and climate change I wonder how many are aware of what James Hansen is saying, i.e. in this paper that “the main obstacle to solution of human-made climate change” is not the “merchants of doubt”. He says “the bigger problem is that people who accept the reality of climate change are not proposing actions that would work”. He discusses the dream that renewables will power the entire world, which he calls “this Easter Bunny fable”. As he says, “it will be a real tragedy if environmentalists allow the illusion of ‘soft’ energies to postpone demand for real solution of the energy, climate and national security problems”. He laments that discussion of nuclear power is such “an emotional matter for some people” that he hesitates to discuss it. He says he is writing a paper with Kharecha to do “an objective post-Fukushima assessment of the role of nuclear power”. He says if you buy the idea that renewables are going to save the world from climate change, i.e. “if you drink the kool-aid”, “you are a big part of the problem”.


Hank Roberts,

Well, the interesting thing about the one-year-later news was the concern about a possible cascading failure if Fukushima had been a severe enough accident to make _other_ nuclear and fuel power plants shut down

The substantive question is whether or not the other plants would have had sufficient time to achieve ‘cold shutdown’. The amount of effort it takes to maintain cold shutdown on a reactor that has been depressurized is considerably less then attempting to achieve cold shutdown on a reactor with a melted core where depressurization would cause a large release of radioactive material.

The problems related to ‘station blackout’ at ‘rods in’ + 1 hour are significantly higher then station blackout at ‘rods in’ + 12 hours.

Obviously if there was a concern that nearby power plants would have to be evacuated then nearby plants would have been ordered to immediately proceed to cold shutdown and all non-essential staff evacuated.


Hank Roberts, sure it could happen. Cohen showed in his book that a child playing with matches can kill an entire city. The chances are astronomically small, but they are not zero.


I’ll be a little contrarian here…it is not just dose delivered via background radiation. It’s also accumulated radionuclides of Iodine and cesium (both isotopes) and what ever else got out that can bio-accumulate.

Cesium doesn’t bio-accumulate. It has a very short biological half life, in fact, measured in a few months. We know from Chernobyl that cesium, even in quite high chronic doses of a few hundred mSv/year, does not pose health risks.

I-131 is a real concern, we also learned from Chernobyl, but it all decayed in 3-4 months time. So why evacuate longer than this?


I said, ‘This is a very tough situation. But you cannot abandon the plant. The fate of Japan hangs in the balance. All those over 60 should be prepared to lead the way in a dangerous place. Otherwise, we’re handing Japan over to an invisible enemy. This would affect not just Japan, but the whole world.

Exaggeration in deus ex machina is easy. No doubt Kan wanted to motivate people in the face of a serious situation, but hyperbole is unnecessary. The fact is, Chernobyl was exactly an abandonement of all cooling indefinately – with only some cover up with sand etc. being attempted that actually made the heatup worse due to the insulating effect of such materials.

If you have no cooling and abandon plant, the volatile stuff, cesium, iodine, krypton, xenon and a few others, will find its way into the environment. This is what happened in Chernobyl, almost all the volatiles were released to the environment. The initial explosion (due to positive void coefficient runaway reactor) and lack of containment to hold up the initial stored energy release, combined with graphite-steam reaction/fire, allowed some of the nonvolatile stuff like plutonium and lanthanide fission products to escape. Those are not present in power reactors elsewhere in the world where people are clever enough not to build reactors with combined graphite moderation and water cooling, no containment, and strong postive void coefficient. Without such elements present you will be hard pressed to conjure up mechanisms to drive the nonvolatiles out.

Chernobyl is exactly a worst case scenario with no cooling to speak of and a reactor that destroyed itself with runaway 10000% power output. Yet Chernobyl was not the end of Europe. It wasn’t the end of the Ukraine, either. I visited Kiev recently on vacation. I can assure you it is a pleasant and amazing city to visit. Leave your hazmat suit at home.


You are right I asume people are as fimilare with items that I am, thanks.
Here is info on pulse type energy (See ) which may cause problems at a nuclear plant or any equipment on the power transmission lines, these produce high energy spike voltages on the power lines in the world. (like a lightning strike but can last longer when it hits). The transmission lines act like a generator with the power lines rotating with the earth through the pulse energy from a source like the sun and nuclear bombs. This is info on solar storm activity in 1859, we have not seen one close to this size since then (see and ( see “The Carrington Event.” which means that years ago they had problems with very small and short runs of power cables, today the power lines are many times larger and longer producing higher voltage surges many times greater than in the past jumping gaps past off switches and breakers. See this site with solar flare strengths from 1976 ( , ranges from X9 to X28+, the1859 is not known but is believed to be 5 times the average (X12) which would be about X60+, equipment back then was very crude and could stand large voltage surges as the equipment was just wire coils and contact switch to send a pulse down the lines, yet telegraph equipment burnt up. This info is at site: ( Telegraph systems all over Europe and North America failed, in some cases even shocking telegraph operators.[5] Telegraph pylons threw sparks and telegraph paper spontaneously caught fire.[6] Some telegraph systems appeared to continue to send and receive messages despite having been disconnected from their power supplies. The pulse estimates for the 1859 flare seem to be a low estimate, I think they are low because they do not want to be quoted in research papers. Good news might be that they have a connection to get a warning ahead of time, but would they all decide to drop off line and even so if there battery and generators fail what will happen and how many plants will be effected, will they all operate OK?


EL,you need to do some more reading on the history of the USSR.
There were many reasons for the breakup of that entity and Gorbachev played a major part.

It is possible that Chernobyl made a contribution but Gorbachev is hardly a dispassionate observer or commenter.


I think an important perspective on risk perception, not considered by Norhaus, Shellenberger or Cohen is the experience and understanding of the preceptor.

The fundamental flaw in Cohen’s “worst possible nuclear accident” analogy is that most observers (and journalists) have a reasonable understanding about gasoline fires and how they can spread. More importantly they have an understanding of how the community deals with these accidents when they occur and does so almost always successfully. These observers can immediately see that Cohen’s straw man is a very unlikely occurrence and certainly no basis for banning gasoline!

Nuclear power and hence nuclear accidents are not well understood by most observers and most journalists. Worse still, most observers and journalists have no understanding about how a nuclear power plant works. They have no understanding or experience of how an accident at a nuclear power plant is dealt with. They have no basis on which to assess the likelihood or seriousness of a nuclear meltdown. Hence the simplistic view “the very fact that such an accident is possible makes nuclear power unacceptable”.

Even telling them that “A person’s risk of being a victim of such an accident is 20,000 times less than the risk of being killed by lightning, and 1,000 times less than the risk of death from an airplane crashing into his or her house” will not fix the problem. They have no basis on which to know whether or not this is true or if it matters. People are struck by lightning every year. Probably in the US a house is hit by an airplane every year (albeit a light aircraft).

The challenge is how to educate people about nuclear power risks. It probably has to start with educating people about nuclear power and go from there. Industrial accidents per se are acknowledged and almost accepted because the consequential risks to the individual are perceived to be minimal. So a few workers killed in a gas explosion at a plant is considered almost par for the course! (There are glaring exceptions like Bhopal.) So I suspect it is not the nuclear industrial accident that scares people but poorly understood dangers from leaking radiation. So nuclear risk education has to include the real risk of radiation sickness which could mean education about specific radioactive isotopes and dose levels. Alas this will go over the heads of many and is not helped by the LNT approach already discussed in this thread.


I found this article from the Guardian, that was published not long after 11/3/11 : – [Ignore the alarmist headline] It gives a fuller account of the ‘worst-case’ scenario modelling done by UK government. It claims that even following damage to the core and spent fuel assemblies, there material would not be carried towards Tokyo in sufficient quantity to be of risk to anyone.



The price of the Chernobyl catastrophe was overwhelming, not only in human terms, but also economically. Even today, the legacy of Chernobyl affects the economies of Russia, Ukraine, and Belarus.

I did not say it didn’t affect those economies; I said it wasn’t the end of those economies or societies. Far from it. It would be stupid to argue the accident had no economic effect. Rad cleanup and building the new sarcofagus are expensive. But certainly not prohibitive. What’s prohibitively expensive is trying to power the Ukraine with solar. That would make Chernobyl look like small change. And continuing to power it with fossil fuels, while financially possibly attractive for the time being, is something we cannot afford.

What I see with Fukushima is again a lot of politics and deliberate misunderstanding of events, and trying to blow everything out of proportions. 90% of the media coverage went to the Fukushima reactors, while 10% went to the disaster that killed almost 20,000 people, destroyed thousands of buildings, and wiped whole villages away.

And you, EL, are happily contributing to the skewness.


Fire is a very dangerous thing and yet is present in every kitchen and a lot of other places. Doing anything dangerous is dubbed “playing with fire”. Production of electricity from coal, gas, oil or nuclear heat is literally plying with fire. Nuclear energy is more compact and the engineers have tried harder to make it safe. Of all the energy systems, the nuclear costs least lives per Mega Watt year compared to others. The calculations are post Chernobyl, which caused a few dozen lives.


(Comment deleted.)
You have finally outed yourself as an anti-nuclear troll rather than a pro-renewable advocate. Persistent complaints by BNC commenters regarding your failure to answer questions, repetitious posts and strawman arguments plus your violation of BNC Comments Policy regarding trolling require that you be blacklisted on BNC forthwith.


There are many interesting comments on this thread and I intend to discuss BEIR VII but that seems sufficiently remote from the Fukushima discussion that I shall use the current Open Thread.


There’s a discussion on the same theme taking place over at SciAm:

Unfortunately, the SciAm blogs are a classic example of what can happen when there’s no moderator or moderation policy: there’s an awful lot more heat than light being generated.

One take I find interesting though, is that Fukushima was in fact a worst-possible-case scenario as nuclear accidents go, but the effects for human life-and-limb are very limited. This interpretation, it’s argued, has the support of the US NRC:

Would love to see this interpretation presented to the German public (that’s where I live). No chance, though. The greens over here, with the media in their pockets, have been very successful, implanting the concept of the GAU or super-GAU (worst conceivable accident) with millions of deaths in the public consciousness. It’s not even possible to debate the issue dispassionately with people.


Another excellent article on the overreaction of the media to Fukushima, contrasting that with the negligible attention paid to the victims of the tsunami is by Michael Hanlon of the Telegraph, who counts himself among the guilty.

‘The world has forgotten the real victims of Fukushima

A natural disaster that cost the lives of thousands of people was ignored in favour of a nuclear ‘disaster’ that never was, argues Michael Hanlon.’

This article is a superb piece of writing that addresses many issues concisely. The final sentence of the article:

‘Nobody, to date, has died as a result of radiation leaks at Fukushima Dai-ichi. Zero – a number you will have read even less about than the 20,000 dead.’


I don’t think the issue is with the health effects of Fukushima as it is now, or will be in the future. I think it has already been shown now without doubt that the health effects will be minor, and only a relatively small area of land will be permanently uninhabitable.

I think the issue of discussion here is could it have been worse, and if so, how bad could it have been. And how likely was it to happen. For instance, what would have been the effect if the Fukushima Dai-ichi workers had evacuated? Would the bottom of the vessel have been penetrated? If so, what would have been the effect? What if there had been a cascading effect at other plants?

Having written all that, I have just realised how vanishingly unrealistic and improbable this chain of events would be. I don’t think there would be vessel breaches at Fukushima Dai-chi, even if the plant was totally evacuated, based on TMI (where 50% of the fuel melted and slumped to the bottom, without breach) – would 100% of the fuel melted and breached the pressure vessel? Perhaps. Would this have threatened the integrity of the containment in any serious way? Probably not. Even if this happened, would it mean that Dai-ni and others would need to be evacuated, resulting in the same happening there? Again, this seems unlikely. Would Tokyo have been at risk of evacuation? Almost certainly not – it’s likely that the materials from the accident would have intensified the contamination in the nearby areas, but would not have diffused in significant quantities to Tokyo to threaten existence there.


Most of the fuel of the Daiichi #1 did melt, and dropped to the bulb space beneath the vessel. There, according to recent analysis, it penetrated about 70 cm of the containment concrete there. But not the metal containment beneath that, and even if it got through that, there’s a total of 10.2 meters of concrete.

The bulk of unit 1’s nuclear fuel went through the bottom of the reactor vessel as well as about 70 centimetres of the drywell concrete below, according to the analysis released today. However, the corium did not breach the steel containment vessel 1.9 metres further down within the concrete, or the boundary of secondary containment some 7.6 metres further still.

Of the 10.2 metres of solid concrete that makes up the floor of the reactor building, the corium is thought to have melted and mixed with the first 70 centimetres only. The natural spreading and expansion of the corium, plus the addition of compounds of concrete, would have reduced the intensity of the heat produced until it reached an equilibrium and solidified in place.

If the plant had been abandoned completey, would the corium have gotten through 10.2 meters of concrete? All the pumps and cooling HXs failed long term, causing a 0.7 meter concrete corium penetration. If there had been no water injection, clearly the depth of penetration would be greater. But the deeper the corium penetrates the more heat is dumped in the heating and melting of concrete, and the more diluted the fission products become in the corium-concrete mixture. It takes a serious beyond design basis accident to get even 0.7 meters, so 10.2 meters of concrete is really a lot, so it looks like the Japanese engineers did consider the worst in this case.

Too bad they didn’t have passive filtered venting overpressure protection systems. This is far more important for protecting the public than highly radioactive blobs forming in the concrete basemat, even if it penetrates through to the soil, this will be such a slow process that the ground (and water boiling out of it like fumaroles) would absorb the heat. There would not be a need for evacuation if they had such systems, because modern filters can remove 99.999% of the radioactivity before venting the excess steam pressure. Airborne emissions were the reason for the evacuation, not a molten corium in itself.


I think I can recall some of the mortality figures given by Jim Al Khalili on the SBS documentary. With Chernobyl he said 6 million people had been exposed and 2,000-2,500 were operated for thyroid cancer. There were 15 thyroid deaths. Other cancers were insignificant. I don’t recall any discussion of birth defects. As we saw with the distressed woman fear of cancer even after 25 years was disabling for some.

With Fukushima after 6 months some 30 workers had received 20 mSv of radiation. These figures are in stark contrast to those bandied about by Greenpeace such as nearly a million affected by Chernobyl.


(Comment deleted. Violation of the Citation rule.)
BNC requires that, except on the Open Thread, your assertions/personal beliefs are backed by reputable peer-reviewed links. Your recent comments are personal opinion and you have not provided any such evidence.


Cyril R., on 5 March 2012 at 5:56 AM said:

Too bad they didn’t have passive filtered venting overpressure protection systems. This is far more important for protecting the public than highly radioactive blobs forming in the concrete basemat, even if it penetrates through to the soil, this will be such a slow process that the ground (and water boiling out of it like fumaroles) would absorb the heat. There would not be a need for evacuation if they had such systems, because modern filters can remove 99.999% of the radioactivity before venting the excess steam pressure. Airborne emissions were the reason for the evacuation, not a molten corium in itself.

The absence of that system is probably due to TEPCO’s desire to avoid paying to install it. That, and the sad way that regulators and overseers in Japan work hand-in-glove with those they are supposed to supervise is all that is needed to avoid sensible safety outlays. Sadly, they’re paying for it now though.


It is interesting that the authors have not actually answered the question in their title. “How close did Japan really get to a widespread nuclear disaster?”

The implication is that they were not close at all, but I would say they came within a half inch. Building spent fuel pools above ground was a foolish mistake. They each contain several core loads of long lived fission products, including cesium and strontium.
(Deleted personal opinion.)

The hydrogen explosions severely damaged the concrete structure.
Spent fuel assemblies can air cool by natural convection two weeks after shutdown if they have a good supply of cool air in a low density array. But the densely packed pools common today cannot.

Unloading those pools to a safe density should have been one of the highest priorities, accomplished months ago.
Except on the Open Thread, your expressed personal opinion of what might have happened needs to be supported by scientific references. Please re-submit with such references.


Bill Hannahan — The hydrogen explosions did essentially nothing to the concrete. The top hall of the reactors was covered, sides and top, by sheet metal. That, of course, was severely damaged.
Please suppy supporting reference.


David B. Benson: what Bill is talking about is that spent fuel pools need active cooling when densely packed and containing relatively fresh spent fuel. So if you use that you better be sure you can always get active cooling or have sufficient space between the fuel elements for passive air cooling. Building it at great height is a wonderful way to ensure you DON’T get active cooling in an emergency; the top floor was non-hardened and its collapse, whether in an earthquake or hydrogen explosion, effectively blocks access to the spent fuel pool. If you look at the timeline to boiling for the top fuel pools, it is clear that water eather leaked (through the SNF assembly gates) or sloshed out of them (by the earthquake). So you have an increased probability of water loss to worry about with high up spent fuel pools, too, and no easy way to add makeup water. And a final disadvantage of higher up spent fuel pools also make the seismic profile less favorable: you want the heavy stuff to be at ground level as much as possible to reduce the seismic profile.

Later BWRs designs have already incorporated this lesson; they’ve got spent fuel pools below ground level, where they should be built.

At the Fukushima NPPs, there was also a central spent fuel pool. This was built below grade. It worked fine. Even when power was cut, its ease of accessiblity, combined with the larger water volume in that pool, ensured good cooling throughout the accident. Simply dropping a garden water hose in them would be sufficient cooling.

The World-Nuclear Fukushima information page, recently updated, has a highly accurate description of events and the technology.


Regarding this comment; “The hydrogen explosions did essentially nothing to the concrete.”

David, please link to inspection report showing that the Stainless Steel liner of the unit 4 spent fuel is fully supported by undamaged concrete. Why did they install additional support under unit 4 spent fuel pool?

This photo seems to show damaged concrete, does it still meet the original seismic qualification?
How would it handle another large quake?


Bill Hannahan, on 6 March 2012 at 5:36 PM said:

But the densely packed pools common today cannot.

On pools for Units #1,#2 and #3 there was a single core in the pool +- a few asembley’s. On Unit 4 for there was slightly less then 2.5 cores in the pool as the reactor vessel itself was undergoing inspection.

Click to access ENGNEWS01_1306813176P.pdf

I see no evidence that ‘dense packing’ was the practice at Fukushima.


Regarding the deleted material from my first comment;

“Had the steel liner of a spent fuel pool ripped open, draining the pool, the rods would overheat, catch fire, melt down, and release an enormous quantity of fission products from the open structure.”

This is supported by the Sandia study previously linked and a NRC study;

“FINDING 3B: The committee finds that, under some conditions, a terrorist attack that partially or completely drained a spent fuel pool could lead to a propagating zirconium cladding fire and the release of large quantities of radioactive materials to the environment. Details are provided in the committee’s classified report.”

Cesium has a low boiling temperature, 671C. Most cesium atoms released deep inside containment will plate out on colder surfaces as they migrate through the plant. cesium atoms released from the open air spent fuel pools are much more likely to escape due to the lack of cold surfaces. The mass of cesium and strontium in the spent fuel pools is several times that in the reactor.
Thankyou for the links you have provided. However you still need to supply them for what in your opinion are “well-known and undisputed facts”.


German Nuclear Inspectors Remember Fukushima,1518,819491,00.html
It happened that a German inspection team was at Fukushima Dai-ichi at the time of the Tohoku earthquake and tsunami. Der Spiegel interviewed two with the transcript in the above link. I found the responses surprising but in a pleasant, positive way.

The most amusing line is to the effect that they only spoke enough Japanese to order a pizza.


David B. Benson –
Interesting interview.

Notice how the reporter was fishing with increasing desperation for a negative take on nuclear power. Typical for the German media.


@David B. Benson,

Partially, but not completely off topic. Did you notice on the same web page as the interview the highly propagandistic and near hysterical graphic of the front page of Der Spiegel about Iran and nuclear power. It has a style rather similar to WWII cartoons and a fine example of how this game is being played.


Been away for a few weeks in NZ and in Adelaide at the festival but had a map posted the other day from an ex ANSTO researcher friend. It shows: Government Released New Radiation Readings in Fukishima as of 10/2/2012. It shows the main radiation plume travelling in a NE direction which means Tokyo was not on the path of the plume. It also shows in table form residence doses times to reach 20mSv [annual dose limit for radiation workers as recommendedby the ICRP]. It seems to me that Tokyo was way out on the edge of the plume and that 20 mSv dose would have taken between 2 and 4 years to accumulate there. It seems to me that we have another example of gross misinformation and false reporting from our journalists and others on this event. Nothing has changed, nor is it likely to. I spoke to the Retired Engineers group in Adelaide the other day and have two more speaking engagements coming up as a result. It seems that Robyn Williams will give me a third and possibly fourth go on Ockhams Razor as well. My now 14 year old nuclear education campaign is at last starting to pay off


Terry, Tokyo should have been evacuated long ago. It’s air pollution, courtesy of fossil fuel burning, is far more dangerous than 20 mSv of ionizing radiation. Why are 13 million Japanese allowed to remain in Tokyo-city, with such dangerous levels of air pollution?


See this site:
Fukushima plants where badly designed against a tsunami as there was a tsunami with waves as high as 100 feet in the last 100 years beside the east coast of Japan, so should have been designed for 20% higher at 120 feet for safety.
This is criminal to put the public in that danger. I believe we need nuclear power but it has to be safe and I do not see it anywhere in this industry so I cannot support it now. If one looks at the past service orders to make changes for safety reasons the owners just stone wall it and refuse to make changes or repairs. The over site and safety comities are paper tigers given the responsibility for making sure the public is safe but have no way of enforcing their requests. The only way is to turn the industry over to the governments in each country so that profit is not a issue just safety, yes it will cost more but we will hand this industry over to our children safe and sound.
See Site:


Oh my. Sorry to be so late to this party.

This reminds me of a painful lesson I learned in the time leading up to y2k. I was placed in a tough situation: international NGO’s insisted that I discover the real risks of y2k, to inform their preparations. Problem was, the facts (there were real issues, but almost all were dealt with professionally and on time) did not jibe with the popular consensus.

I learned two major lessons from that journey:

1) Most people, once they have taken action based on believing XYZ about something, will find it very difficult to change their mind, even if presented with unequivocal facts to the contrary.

2) When it comes to risk, the “pass-the-word-along” game spirals out of control exponentially. Typical sequence (based on power grid risks at the time):
– The inside experts expected no outages at all, but positioned assets in case of a very short glitch.
– Observers saw those preparations and thought “ah HA! They expect a few minutes outage; we’d better prepare for hours…”
– Next level: “ah HA! They expect hours… we’ll prepare for days…”
– Next level: “…weeks…”
– Next level: “…months…”
– Next level: “…a few years…”

People who don’t understand risk look at that and say, “See?! ANY risk is too much risk.”

Big Sigh.


I wrote an article about the Frontline documentary. I was amazed to learn at the end of the film that the entire problem had been brought under control by a single fire truck pump and a few strategically placed hoses. Had they done that at day one, things might have been very different.
BNC requires refs to support your comments. Please link to your article and the Frontline documentary .Thankyou.


“Had they done that at day one, things might have been very different.” That is your opinion, show me where they could have set up the hoses with no pumps to spray water because the power was not available for a long peroid of time and even if they had power the pumps at the sea where out as well.

References have been requested from the original commenter.


A “simple fire truck” cannot pump water into a pressurized reactor core. Fire truck pumps cannot produce a pressure head of >>70 atmospheres.

First you have to reduce the pressure in the core. But there were no cooling pumps. So the heat built up, increasing pressure! So they quenched the excess steam from the reactor core into the donut shaped water pool. But there was not enough water in there. They just delayed the problem from the core into the containment, and had to vent the pressure later, from the donut shaped pool.

One of the best references on the sequence of events is the World Nuclear information article on Fukushima:

One of the things I don’t understand is that they apparently had a filtered venting system where the boiled steam from the seawater injection to the reactor vessel could be removed. You’ll see that from early pictures of that time, a rectangular grate where water vapor comes out of. But they chose to wait with venting the containment, till it reached twice design pressure, forcing the top flange open and forcing fission products and hydrogen into the service floor. Why let the pressure build up like that if they had a filtered path for venting? Was it such a difficulty to open the valves manually? Or was it politicians pulling the strings?


A “simple fire truck” cannot pump water into a pressurized reactor core. Fire truck pumps cannot produce a pressure head of >>70 atmospheres.

Go watch the documentary. They didn’t mention the reactor core. Possibly they were spraying the cooling ponds.


richard123456columbia said:

“Had they done that at day one, things might have been very different.” That is your opinion, show me where they could have set up the hoses with no pumps to spray water because the power was not available for a long peroid of time and even if they had power the pumps at the sea where out as well.

A fire truck pump is typically run by the truck’s engine. Like the pumps on all firetrucks, they don’t not need an external source of electricity. In the documentary they interviewed some of the firemen.


From the link you provided:

RPV pressure was reduced by venting steam into the wetwell, allowing injection of seawater using a fire pump from just before noon.


Cyril R. — My understanding (which could well be wrong) is tat there was no procedure in the manuals for opening vents without electricity. So it took some time to figure out a way to do so.


@ biodiversisit
The link to the Frontline page was a prime example of how psychologically, and therefore physically, damaging the misinformation regarding nuclear power and radiation, is to the local people. Those fearmonging individuals and organizations are responsible, as they were at Chernobyl, for robbing residents, and their children, of a future free from crushing anxiety about their health.They should hang their heads in shame!


Cyril R., on 28 March 2012 at 5:42 PM said:

Why let the pressure build up like that if they had a filtered path for venting? Was it such a difficulty to open the valves manually? Or was it politicians pulling the strings?

The TEPCO severe accident procedures provide guidance for venting containment. The guidance directs venting when containment pressure reaches the maximum operating pressure if core damage has not occurred……..In this case, the Emergency Response Center personnel could not verify the integrity of the core, and the associated guidance was applied in the decision to vent Unit 1. Emphasis mine.


But they allowed the pressure to rise to 2x the design pressure. This likely caused the unfiltered release path through the containment vessel flange, which then caused the hydrogen explosion. Better to have filtered release and no hydrogen explosion.


Cyril R, on 30 March 2012 at 1:11 AM said:

But they allowed the pressure to rise to 2x the design pressure.

Read further down in the NEI report…

The first indication of increasing containment pressure was not available until 2350 on the night of the event, when workers connected the temporary generator which was being used to provide some control room lighting to the containment pressure instrument.


Which shows that you don’t want to be operator dependent on venting. In stead use an automatic system.

Just for my own amusement I’ve designed a siphon isolated system that is just a U-pipe filled with water, one end connecting to the containment, the other to the outside. Carbon and HEPA filters on both ends as well to remove the fission products. It works very simple. The pressure in the containment rises, the water in the U-tube is pushed down. When the pressure rises so much that the water reaches the bottom of the U-tube, the water lock is broken and the excess steam and hydrogen (fission products are already filtered at this point) bubble up through the other side of the water column, venting to the outside. Very simple, fully automatic passive venting system. Every nuclear plant should have such a pipe.


Is this the best thread to discuss the groundwater radioactive contaminants and the leakage of these groundwaters into the Pacific Ocean at Fukushima? The NYTimes have direct quotes from experts working with TEPCO that are not reassuring:

Despite Mr. Klein’s criticism, he said Tepco was working hard to clean up the plant. He also said he did not believe it had deliberately covered up problems with the groundwater, though reporters have been regularly asking the utility for more information.

“From what we’ve seen, it’s more of what I’d call incompetence rather than a cover-up,” Mr. Klein said at a news conference in Tokyo after meetings with Tepco executives. He is a former chairman of the United States Nuclear Regulatory Commission.

Lady Barbara Judge, the former chairwoman of the United Kingdom Atomic Energy Authority who also sits on Tepco’s committee, was more blunt.

“I have personally been discussing with people in Japan and outside the fact that Tepco is on a journey of being reborn as a nuclear operator,” she said. “And to find that the communication with respect to the water problem had been so difficult and so late was devastating.”

For weeks, Tepco officials had emphasized that groundwater containing high concentrations of radioactive tritium, strontium and cesium discovered in observation wells at the plant last month did not pose a threat to the nearby Pacific. The utility held its ground even after Japan’s nuclear safety chief said last week that the plant had most likely been leaking contaminated water, probably since the disaster more than two years ago.

On Monday, Tepco finally disclosed that there was a leak. It also released evidence showing that the water in the wells along the shoreline was rising and falling with the tide, indicating that there was no barrier between the wells and the ocean. The company said that different sections had been in charge of varying aspects of the data and that officials had not made the connection earlier.


Does Tepco’s math make sense here, regarding the above (assuming my first post makes it through moderation eventually)? The news story comes from Tepco and Tepco’s followup is:

That says this:

“1,800 mSv/h is approximately 3.5 times higher than the control level of the equivalent dose for skin, which is 500 mSv/year”

comparing “per hour” with “per year” seems wrong somehow.

The news stories come out a day or more before Tepco puts their press release on their website, near as I can tell. Presumably they give the press releases to the newspapers first.


Hank, can you comment on thisRussia spent huge amount of money on Cher.. breaking up the country, USA is only country with enough money to solve 3/11, will it be to much for them. The USA may end up bankrupted by the time they finish or give up. This 3/11 cost financially and health wise is going to be very very high and its effects will go on for centuries. Has anyone figured out the saturation point of the pacific if the radiated water can not be stooped and how long till it does?
When or if fuel sinks into the earth there will be great pressure on the fuel, what effect will this have, will it go critical and blow up or will it keep increasing the amount of radiation as it goes deeper or some thing else? There must be some thing bad or Russia would have let the fuel sink into the earth.:


Perhaps worth a look — up until 1998, this area’s geology was thought to be stable and safe. Then a stretch of heavy rain saturated the ground, causing

“… the 1998 Fukushima disaster in Japan, which occurred in the area …. Before this disaster,… had not been reported to have generated many landslides as a result of intense rainfall. It had previously been supposed to be rather stable to landslide….”

Click to access fukushima.pdf


In response to a blogpost on August 29, 2013 by Ed Lyman, PhD in physics and senior scientist at the Union of Concerned Scientists.

I posted the following question.
Why didn’t TEPCO bury Fukushima’s reactors in leaded sand, as was done at Chernobyl?

I ask this question because my colleague, who has a PhD in physics, wrote recently:
2.5 years – or 1000 days – after 3 of 6 of Fukushima’s nuclear reactors melted, 3 radioactive cores are cooled daily by 300 tons of water. Popping like 1000 giant highly radioactive mushrooms, 1000 tanks filled with 300 tons of radioactive water crowd the plant, with one added each day. At least 3 tanks leak, one leaches 1.8 Sv/hr – the equivalent of 100,000 chest X-rays per hour, or 1000 CT scans each hour.

Soviets buried Chernobyl’s reactor in 4500 tons of leaded sand within 4 days by helicopter, added a cooling barrier underneath in 10 days, and a sarcophagus in 5 months in 1986.

In 2013, we CAN be better than this!

They should have asked for help from those who had gone through it before. …

The 3 reactor cores and fuel are slowly dissolving into the ocean from the many rains water run-off, while at the same time TEPCO has turned into a high volume factory of highly contaminated water that they do not even seem to understand should be decontaminated daily and recycled for cooling. They have to encase the 3 cores and the 5 spent fuel pools in leaded silica (sands melt into silica on the hot cores) before it is too late – ASAP!

Can an expert please comment on this PhD physicist’s statement?


If at full power as I seem to recall they were, the three Fukushima cores were making 6142 thermal megawatts when the earthquake hit and were down to 41 MW a day later. Melting must have been occurring around this time.

Now they’re down to 0.76 MW, so there is no doubt they have long since refrozen, according to the “decay heat” setting of

Chernobyl was a totally different thing. Experience there is not applicable to Fukushima. Dumping stuff on the remains may well have been a classic late-Soviet waving-a-dead-chicken practice, since much of the radioactivity had already, literally, flown. You can see its ground track here.


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