Hot News Nuclear

Fukushima rated at INES Level 7 – what does this mean?

Hot in the news is that the Fukushima Nuclear crisis has been upgraded from INES 5 to INES 7. Note that this is not due to some sudden escalation of events today (aftershocks etc.), but rather it is based on an assessment of the cumulative magnitude of the events that have occurred at the site over the past month (my most recent update on that is here).

Below I look briefly at what this INES 7 rating means, why it has happened, and to provide a new place to centralise comments on this noteworthy piece of news.

The International Nuclear and Radiological Event Scale (INES) was developed by the International Atomic Energy Agency (IAEA) to rate nuclear accidents. It was formalised in 1990 and then back-dated to events like Chernobyl, Three Mile Island, Windscale and so on. Prior to today, only Chernobyl had been rated at the maximum level of the scale ‘major accident’. A useful 5-page PDF summary description of the INES, by the IAEA, is available here.

A new assessment of Fukushima Daiichi has put this event at INES 7, upgraded from earlier escalating ratings of 3, 4 and then 5. The original intention of the scale was historical/retrospective, and it was not really designed to track real-time crises, so until the accident is fully resolved, any time-specific rating is naturally preliminary.

The criteria used to rate against the INES scale are (from the IAEA documentation):

(i) People and the Environment: considers the radiation doses to people close to the location of the event and the widespread, unplanned release of radioactive material from an installation.

(ii) Radiological Barriers and Control: covers events without any direct impact on people or the environment and only applies inside major facilities. It covers unplanned high radiation levels and spread of significant quantities of radioactive materials confined within the installation.

(iii) Defence-in-Depth: covers events without any direct impact on people or the environment, but for which the range of measures put in place to prevent accidents did not function as intended.

In terms of severity:

Like the scales that describe earthquakes or major storms, each of the INES scale’s seven levels is designed to be ten times more severe that the one before. After below-scale ‘deviations’ with no safety significance, there are three levels of ‘incident’, then four levels of ‘accident’. The selection of a level for a given event is based on three parameters: whether people or the environment have been affected; whether any of the barriers to the release of radiation have been lost; and whether any of the layers of safety systems are lost.

So, on this definitional basis, one might argue that the collective Fukushima Daiichi event (core damage in three units, hydrogen explosions, problems with drying spent fuel ponds, etc.) is ~100 times worse than TMI-2, which was a Level 5.

However, what about when you hit the top of the INES? Does a rating of 7 mean that Fukushima is as bad as Chernobyl? Well, since you can’t get higher than 7 on the scale, it’s impossible to use this numerically to answer such a question on the basis of their categorical INES rating alone. It just tells you that both events are in the ‘major league’. There is simply no event rating 8, or 10, or whatever, or indeed any capacity within the INES system to rank or discriminate events within categories (this is especially telling for 7). For that, you need to look for other diagnostics.

So headlines likeFukushima is now on a par with Chernobyl‘ can be classified as semantically correct and yet also (potentially) downright misleading. Still, it sells newspapers.

There is a really useful summary of the actual ‘news’ of this INES upgrade from World Nuclear News, here. It reports:

Japanese authorities notified the International Atomic Energy Agency of their decision to up the rating: “As a result of re-evaluation, total amount of discharged iodine-131 is estimated at 1.3×1017 becquerels, and caesium-137 is estimated at 6.1×1015 becquerels. Hence the Nuclear and Industrial Safety Agency has concluded that the rating of the accident would be equivalent of Level 7.”

More here from the IAEA:

The new provisional rating considers the accidents that occurred at Units 1, 2 and 3 as a single event on INES. Previously, separate INES Level 5 ratings had been applied for Units 1, 2 and 3. The provisional INES Level 3 rating assigned for Unit 4 still applies.

The re-evaluation of the Fukushima Daiichi provisional INES rating resulted from an estimate of the total amount of radioactivity released to the environment from the nuclear plant. NISA estimates that the amount of radioactive material released to the atmosphere is approximately 10 percent of the 1986 Chernobyl accident, which is the only other nuclear accident to have been rated a Level 7 event.

I also discussed the uprating today on radio, and you can listen to the 12-minute interview here for my extended perspective.

So, what are some of the similarities and differences between Fukushima and Chernobyl?

Both have involved breeches of radiological barriers and controls, overwhelming of defence-in-depth measures, and large-scale release of radioactive isotopes into the environment. The causes and sequence of the two events were, however, very different, in terms of reactor designs, the nature of the triggering events, and time-scale for resolution — this is a topic to be explored in more depth in some future post. The obviously big contrast is in the human toll and nature of the radioactive release.

The Chernobyl event killed 28 people directly via the initial explosion or severe radiation sickness, and other ~15 died as directly attributed result of radiation-induced cancer (see the summary provided today by Ben Heard on Opinion Online: Giving Green the red light). Further, Chernobyl led to a significant overexposure of members of the public in the local area and region, especially due to iodine-131 that was dispersed by the reactor fire, and insufficient protection measures by authorities. An increase in thyroid cancers resulted from this.

In Fukushima, by contrast, no workers have been killed by radiation (or explosions), and indeed none have been exposed to doses >250 mSv (with a ~1000 mSv being the dose required for people to exhibit signs of radiation sickness, through to about 50 % of victims dying after being exposed to >5000 mSv [see chart here]). No member of the public has, as yet, been overexposed at Fukushima. Further, much of the radionuclides released into the environment around Fukushima have been a result of water leakages that were flushed into the ocean, rather than attached to carbon and other aerosols from a burning reactor moderator, where they were largely deposited on land, and had the potential to be inhaled (as occurred in Chernobyl).

So is Fukushima another Chernobyl? No. Is it a serious accident? Yes. Two quite different questions — and answers — which should not be carelessly conflated.

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.

158 replies on “Fukushima rated at INES Level 7 – what does this mean?”

P.S. — standard recommendation for reading science sources — read the footnotes, check that the cited paper actually says what the text claims, see how often that paper was cited by later work, look at the later work. This can be slow and tedious; it’s how it’s done, if you want to put together a picture of what’s available.

This is why those of us less than competent in particular areas look for overview articles and consensus statements–and are wary of PR spin.

Take for example one cite
(Pflugbeil and Schmitz-Feuerhake, 2006).
from the Yablokov document published by the National Academy cited. Looking into that as described above leads to: which cites ongoing work in Europe and compares it to prior work: “These post-Chernobyl observations are consistent with those in the United Kingdom, the United States, and West Germany following the atmospheric nuclear bomb tests of the 1950s…” (cites in original)

This is the sort of work we ought to read and think about before relying on claims — in any direction — that are beliefs and opinions posted on blogs.

There are facts out there. There are new ones being written down.



Moderator wrote:

As has been pointed out up-thread by some commenters, your links don’t always confirm what you are saying. Fortunately, some on the blog read them in full? Have you?
Any future such violations of the citation policy will be deleted.
You are now on permanent moderation.

Could the moderator please be more specific … especially when threatening someone with deletion of posts. A reader said the quote was unattributed in the link I provided, so I provided a new link where quote is attributed (directly in the words of a TEPCO official). I don’t see any violation here (but a specific response to a reader’s request, and a link that directly provides the pertinent information).

I was also asked by a reader to provide information about the health consequences of radiation related to the higher levels reported by Japanese officials (necessitating a category 7 rating). I did so here too: and provided information on health concerns expressed by Japanese officials (in the press conference announcing the category 7 upgrade), health concerns in Europe (including advisories on food restrictions), and reports in US on food exceeding EPA food safety guidelines by milk. And the response by the moderator: “your links don’t always confirm what you are saying.” What about a specific statement, report, or data set confirming health concerns from radiation does not support what I am saying?

I can see where readers here might want to dispute these low levels, and suggest these reports are minor or somehow unfounded (and take issue with respect to degrees). But they are direct replies to reader requests, they provide specific links to back up my claims, and they speak directly to the issue of health concerns spreading far and wide from this particular accident. It was JohnG who first suggested the link I provided was an inaccurate summary of statements made by TEPCO officials. I have since proven him wrong (and it is inaccurate to suggests the links to not support statements I have made in this thread.
If you subsequently posted material that backed up your claims and refuted the arguments from fellow commenters than obviously moderation works to keep this a scientific site.


Hank Roberts, on 14 April 2011 at 12:47 AM said:

> Yablokov … from the NYAS site

Good link, and people should take the time to read that carefully and think it through before proclaiming it wrong. I find it ironic that people are so willing to believe the information from the government of the USSR, and so quick to conclude that the people who came afterward must be less careful of the truth.

It says “The scientific literature on the consequences of the catastrophe now includes more than 30,000 publications, mainly in Slavic languages…. The Chernobyl Digest—scientific abstract collections—was published in Minsk with the participation of many Byelorussian and Russian scientific institutes and includes several thousand annotated publications dating to 1990. At the same time the IAEA/WHO “Chernobyl Forum” Report (2005), advertised by WHO and IAEA as “the fullest and objective review” of the consequences of the Chernobyl accident, mentions only 350 mainly English publications.”

Some work needs to be done translating these.

It’s not appropriate to insist that if it’s not in English it’s not acceptable information.


Something else I have read in regard to Eastern European medical and scientific studies, was that because the studies and papers were not published by a leading scientific or medical journal, they were omitted from the UN backed studies. I have never read what their reasoning was, but it seemed to be mainly political, not scientific.


“Is anybody here aware of the Yablokov report?”

It is mentioned in George Monbiot’s article from a week ago which attacks the evidence provided by anti-nuclear activists (

This is what he says about the Yablokov report:

“A devastating review in the journal Radiation Protection Dosimetry points out that the book achieves its figure by the remarkable method of assuming that all increased deaths from a wide range of diseases – including many which have no known association with radiation – were caused by the accident”
(link to excerpt from review: – unfortunately the full version is per-pay only)


“The academy has given me this statement: “In no sense did Annals of the New York Academy of Sciences or the New York Academy of Sciences commission this work; nor by its publication do we intend to independently validate the claims made in the translation or in the original publications cited in the work. The translated volume has not been peer-reviewed by the New York Academy of Sciences, or by anyone else.”

So the NYAS was just a publisher and does not back the data/conclusions presented in the book.

The link was deleted because, unlike yourself and some others, the comment was not provided with any in depth analysis of the contents of the 349 page document. As you have put in the work to do so maybe you would like to post the link.


And yes, they published it — I’m not suggesting it’s given authority by the publisher, but that the material can be checked by following the footnotes and reading the citing papers that have referenced it.


I think it is pointless to compare Fukushima to Chernobyl- they are very different accidents – for all the reasons mentioned. As usual the media has it all wrong. Nothing new.

But for those that think 7 is too high…

If you were evacuated at a moments notice from your home, likely unable to work because your work is also within the exclusion zone, and you’ve been in this state for 30 days now, with no end in sight I would not fault you for ranking this as at a level of “the most serious incident possible”.

What can be worse than being evicted from your home and community without notice and with no date certain that you will be allowed to resume your life?

Anyone that remembers my prior comments here knows I am far from anti-nuclear but I can’t argue with level 7. Regardless that no one has been killed by this incident, the severe disruption to 200,000 lives cannot be ignored. Unless you are arguing this from a theoretical point of view in the comfort of your own easy chair at home.

My own speculation is that the authorities likely believe that there is no clear end in sight that would allow the return of those 200,000 dispossessed souls. It may not be getting worse but it is also not getting any better and, given that LNT is the foundation for determining when those people can return (right or wrong – it makes no difference), the near to mid-term future is likely quite bleak for the exclusion zone.


> speculation … no clear end in sight

I think that’s what they said explicitly; there’s certainly no end point stated anywhere, and “the areas beyond 20km radius could be exposed to over 20mSv during the course of the next one year, approximately until next March.”

In the news, the public is now hearing confirmation of fuel damage in the spent fuel pools:

“TOKYO, April 13 (UPI) … some of the spent nuclear fuel rods stored in the No. 4 reactor were damaged….
… The utility has estimated 25 percent to 70 percent of the nuclear fuel rods in the Nos. 1, 2 and 3 reactors have been damaged.
Tokyo Electric said a water sample taken Tuesday from the No. 4 unit’s spent nuclear fuel pool indicated damage to some fuel rods for the first time, detecting higher-than-normal levels of radioactive iodine-131, cesium-134 and cesium-137.”


“If you were evacuated at a moments notice from your home, likely unable to work because your work is also within the exclusion zone, and you’ve been in this state for 30 days now, with no end in sight I would not fault you for ranking this as at a level of “the most serious incident possible”.”

Once could argue that being dead is a lot more serious incident than not being able to work for 30 days.

Anyway, deciding INES levels is no simple matter, otherwise there would not be a 200+ page IAEA manual for it (


@John Doe: The Yablokov report compares desease rates accross similar populations before and after the Chernobyl accident. See for example . Specialists will probably argue about this, but the report is really loaded with dozens of analyses like this one.

The NYAS disclaimer is a rather standard disclaimer. It was issued in April 2010, four months *after* they published the report itself:


Looking at the INES levels ‘7’ the categories are simply allocated ‘General Descriptions’. I’ve just seen on the Kyodo agency:

“Excessive radioactive cesium found in fish caught off Fukushima
TOKYO, April 13, Kyodo
Radioactive cesium 25 times above the legal limit for consumption was detected Wednesday in young sand lance caught off Fukushima Prefecture, the Ministry of Health, Labor and Welfare said.
One of the sample fish had a level of cesium of 12,500 becquerels per kilogram about 500 meters off the city of Iwaki, and 35 kilometers from the crippled Fukushima Daiichi nuclear power station, it said. The limit is 500 becquerels under the Food Sanitation Law.”

Bear in mind the distance from Daiichi, the long half life and the importance of fishing to Japan there is going to have to be a lot more in the way of planned countermeasures than better news management..


[Comment deleted. Violation of the citation policy. As described after one of your previous comments]


@François Manchon

I am not equipped to criticise the Yablokov report. I just posted what material i found on the topic. I’ll leave it to experts to evaluate whether it is credible or not.

(However, the method of judging impact of radioactive fallout by using statistic for diseases that have no known association with radiation did leave me with a raised eyebrow.)
As FM claimed he was not equipped to criticize the report he should not have posted it. One of the demands of the citation rule is that the material has been read, digested and understood by the poster. The original comment and link was, therefore, deleted. However some others are taking the time to do his work for him and these comments have been posted.


Is is possible that the Japanese government increased the level to 7 for political purposes.. to garner assistance from the world for clean up, containment, etc? I would think so, logically speaking.


> “no known association”

Follow the footnotes and look at the citing articles.

Quotes paraphrasing paywalled reviews are rhetoric but won’t lead you to any new facts.

Pushing the conversation to extremes of rhetoric instead of using pointers to look up science studies isn’t going to help anyone understand the facts as they’re worked out.


“Quotes paraphrasing paywalled reviews are rhetoric but won’t lead you to any new facts.”

Actually, i was not referring to any reviews but rather the book itself(page 13 of the book PDF):

“Increased cardiovascular disease
with increased frequency of heart attacks and ischemic disease are evident. Average
life expectancy is accordingly reduced. Diseases of the central nervous system in both
children and adults are cause for concern.”

Now, i am no expert, but i did not know cardiovascular diseases were known to be caused by radiation exposure. Have there been any studies suggesting the opposite?


re: “Increased cardiovascular disease
with increased frequency of heart attacks and ischemic disease are evident.”

That could be stress, even if radiation is ruled out. Level 7 events are stressful, and exacerbated when the regional authorities are untrustworthy.

But if you have contemporaneous bump in ailments that absolutely could not be direct or indirect results of the L7 event, then you might have a control that could be subtracted from all the other charts.


> i did not know

Neither did I, until I looked it up. “Hey, who knew?” is usually answered “those who study it.”

Start by doing that yourself, or follow what I tried; read to find better search terms to refine the results.

for a general background , and

which finds many; just as examples from p1:

Radiation-associated cardiovascular disease
… Risk is lifelong, and absolute risk appears to increase with length of time since exposure.
Cited by 158

Radiation-associated cardiovascular disease: manifestations and management*
… survivors treated with radiation remain at increased risk of cardiovascular disease. …
Cited by 66


Add the word “mechanism” to your search, do it in Scholar, and limit it to the recent years to get summary articles; here’s one:

Cardiol Res Pract. 2011; 2011: 317659.
Published online 2011 February 27.
doi: 10.4061/2011/317659.
Radiation-Induced Heart Disease: A Clinical Update

Again, this sort of medical science may be part of the reasoning behind the INES level 7 classification; but they haven’t said specifically and may well not know enough to say.

A lot of research may come out of these events, if there are funds to do the followups.


I would like to see some reasonning following that event, not people getting carried away for 3 pCi/kg of I-131, or saying we need 79 half-lifes to remove radioactive stuff.

I am fed up with fears not based on facts and sound science. I need to see people with critical thinking.



@Hank Roberts

Fair enough – tho i noticed those articles linking cardiovascular diseases to radiation exposure are related to high doses, not to long-term low-dose exposures like those of nuclear fallout after a powerplant accident.

For instance, the article you mentioned

“Radiation-associated cardiovascular disease
… Risk is lifelong, and absolute risk appears to increase with length of time since exposure.
Cited by 158 ”

refers to radiotherapy treatment of cancers, which are rather brutal doses of radiation, 60-80 gray( With 1 gray being roughly equivalent to 1 sievert, this total treatment exposure rivals that of next to the chernobyl reactor right after explosion:


The NYAS disclaimer is certainly NOT a standard disclaimer for any prestigious scholarly publication. This is called getting caught with your pants down after not having properly identified the quality of the published work. No such statement would have been issued if the cited papers were properly peer reviewed and held in high regard for their scientific merit. Essentially, this reads like an embarrassing retraction. That is certainly how it would be viewed in my own scientific field.

One thing I do not understand about the ongoing discussions is the willingness of some posters to reach well beyond their own expertise, and pretend to have the capability to evaluate professional materials from completely unfamiliar disciplines. We have collections of medical reports, scholarly work on radiology, nuclear engineering, and essentially no experts capable of properly evaluating the material. Why is this allowed to be posted? The internet gives people access to information, but certainly does not grant them access to expertise. Despite what you may think, posting scholarly works, when you have no ability to provide proper interpretation of the material, is not informing other readers. Instead it adds to the confusion. This is especially true of cherry picking quotations from carefully constructed scholarly material which needs to be consumed in whole by an expert familiar with the terminology and background material before it is properly understood.
“One thing I do not understand about the ongoing discussions is the willingness of some posters to reach well beyond their own expertise, and pretend to have the capability to evaluate professional materials from completely unfamiliar disciplines”
BNC agrees with you. In fact it is one of the criteria we apply to citations. Consequently, when moderation resumed the original comment was deleted for violation of the citation rule.


Aaron. Yep. We’re all speculating why they chose to go to INES level 7. Maybe it’s just the ongoing leak; maybe it’s the estimate of longterm effects. We can’t know, so all we can do is speculate on the reasoning.

It should lead to research:
Editorial: The Precautionary Principle and Scientific Research are Not Antithetical

“… antagonism to scientific research among those advocating action often reflects their justified frustration at the slowness of the scientific process, the weakness of scientific methodology, the uncertainty of risk assessments, and their opponents’ overuse of the argument that additional research is needed before any action can be taken. Advocating action without waiting for definitive science has been interpreted by some as a reason to stop research. But the opposite should be the case: acting on the Precautionary Principle should automatically trigger research….”

One of the papers citing that one leads to this article that I think applies to this whole issue of assessing risk:
Epidemiology. 2008 January; 19(1): 158–162.
doi: 10.1097/EDE.0b013e31815be031.
Seven deadly sins of environmental epidemiology and the virtues of precaution*

As always, much worth reading in the footnotes:

The Japanese authorities went directly to INES level 7–we’re all wondering if they know more not yet said.


From that latter article, this is the one that made me think of the reaction to those European non-English studies — the first sin, Pride:

“The proud epidemiologist, who overzealously highlights methodological difficulties, or failure to reach statistical significance, at the same time also ignores the innate tendencies of bias toward the null hypothesis.5 Although frequently overlooked, a noisy study is more likely to fail in revealing a true causal link rather than creating spurious associations,9,10 but the literature is nonetheless replete with inferences that misclassification of exposure is an explanation for a positive finding.10
Perhaps the most pervasive symptom of Pride in epidemiology is the condescending attitude toward epidemiology studies from other countries or cultures, most often reflected as an emphasis on major epidemiology journals and English-language literature….”


Clever people have thought about nuclear risk for 75 years, yet we see two major system failures at incidences that would indicate a problem with the risk that were projected. I think the fact we have had two major incidents in 50 years is an indication of a risk assessment error. Until we identify why this is so, I think it is not wise to project the building of 1000’s of new reactors. What went wrong with the past risk assessment approaches. We can’t keep saying we didn’t expect this or that in the analysis. If we have a major nuclear incident due to a terrorist act – will it be because of bad risk assessment, or because we never took the possibility seriously?


Aaron, thanks for your view on the NYAS disclaimer.

Regarding expertise or lack thereof: this is exactly the reason why I posted this question. I would love to read what field experts think about this report.
As per the citation policy, you are expected to understand and comment on links you are posting. Posting a 349 page PDF which you obviously have not read and understood violates the citation policy and as such your original comment was deleted.


To my surprise,
Preston, D.L., Y. Shimizu, D.A. Pierce, A. Suyama, and K. Mabuchi. 2003. Studies of mortality of atomic bomb survivors. Report 13: Solid cancer and noncancer disease mortality: 1950-1997. Radiat Res 160:381-40
being the sizth page thereof
considers other ill-effects than just cancer.


David Mackenzie: According to FAO Fisheries database and the FAO Food Balance Sheets … unfortunately, I can’t link to the output of the query …
fish&seafood is 163 of a 2881 Calorie daily food supply and about half is imported. Saying fish is imported means it is caught by a non-Japanese boat outside of Japanese waters. But plenty of non-imported fish comes from Japanese boats working outside of Japanese waters … but I don’t have data on how much “plenty” is. The bottom line is that any impact on fish consumption in Japan will be small and localised.


@Hank Roberts (6:03am) “We’re all speculating why they chose to go to INES level 7.”

We shouldn’t be. If I’m reading the manual correctly (as per the excerpts I posted back at 9:23am 13 April), the Level 7 designation is a perfectly straightforward, necessary consequence of the calculation of total I131 becquerels released exceeding a certain threshold. There was no ‘chose’, once that calculation had been made.

The only room for speculation is possibly why they ‘chose’ to perform and/or release that calculation at this point in time. In this regard, I don’t think it could have been done validly until repeat airborne monitoring flight data were received (so that total becquerels and proportion of I131 could be estimated), such has only occurred a week or so ago.


@GRL Cowan yes, I should have mentioned that, however those data have only started coming in relatively recently too.


@Hank Benson
you say “There are facts out there”. Fine.

But it is very difficult for anyone in the public that has not access to a well endowed university library (with subscription to most journals) to dig into the references. And indeed the paper that you quote (Pflugbeil and Schmitz-Feuerhake, 2006) is itself a smorgarsbord of links, most of them to abstracts only.

There is something fundamentally wrong when knowledge that derives essentially from public funding (both for production and peer-review) cannot be made accessible to the public. If we ever want to have informed democratic debate on scientific matters, fundamental scientific knowledge should be open source, not a source of income from rent-seeking publishing houses like Elsevier.

So what is left for the rest of us ? Review cautiously the underlying reasoning of the author(s) to see how they link facts that may or may not be true to conclusions. On that score the Yablokov report doesn’t fare well:

Questioning, I quote, “Western scientific protocol” (as if was justified to have different standards for “western” and “eastern” science !) is not for me the best way to achieve credibility.

Also, the most quoted claim : “It is safe to assume that the total Cher- nobyl death toll for the period from 1987 to 2004 has reached nearly 417,000 in other parts of Europe, Asia, and Africa, and nearly 170,000 in North America, accounting for nearly 824,000 deaths worldwide.” is presented with no reference whatsoever, and the reasoning is not properly detailed.

Finally, there is the unprofessional translation. For instance referring to the Student test as “reliability of distinctions by Student” clearly shows that the translator isn’t a scientific or someone versed in scientific translation. This is not a detail, accurate wording counts, especially when one wants to confront conventional wisdom.
I therefore disagree with you on the language issue. I am not a native english speaker but I wholeheartedly endorse the obligation to translate any relevant scientific fact into science lingua franca. Not doing so is for me a sign of disrespect to international peers.

It is a pity because I think this report references many useful pieces of information, such as, for instance, the relative importance of internal contamination (ingestion and inhalation) compared to external exposure. I believe it will be the major long term issue of the Fukushima accident, albeit on a reduced scale as compared to Chernobyl.


Ah, here is the range the government gave with the announcement, I hadn’t seen these numbers:

“The nuclear regulatory agency under the Economy, Trade and Industry Ministry and the Nuclear Safety Commission of Japan, a government panel, said that between 370,000 and 630,000 terabecquerels of radioactive materials have been emitted into the air from the Nos. 1 to 3 reactors of the plant….

… ”Our estimates suggest the amount of radioactive materials released into the air sharply rose on March 15 and 16 after abnormalities were detected at the No. 2 reactor,” Hirose said. …

The safety commission said it estimates the release has come down to under 1 terabecquerel per hour.”



What can be worse than being evicted from your home and community without notice and with no date certain that you will be allowed to resume your life?

– Having your 3 year old daughter die of a chest infection bought on by cooking with wood or cattle dung.

– Having your crop wiped out by a flood, drought

– Being left to starve in the evacuation zone (many animals have reportedly just been left).

– I could go on for a long time. But at a guess, I’d say most of the evacuees will be thankful if they have something to return to … many of their compatriots don’t. The evacuees understand that there are many things worse than being evacuated.

I don’t doubt the technical accuracy of giving this disaster a 7. But there is a serious problem with the way this scale is defined. Personally, I’d prefer a 3D or 4D scale: financial x acute radiation problems x long term radiation impacts x inconvenience

Trying to squash multi-dimensional problems into one dimensional space is always tough and usually silly.


Curious. So many people here keep posting the death count comparisons between this and chernobyl. Anyone know how long after the accident at Chernobyl it was before the first deaths occurred?


Which number could it now go to if another major aftershock centered underneath the plant or another tsunami, that evacuates the work crews, stopping water hosing…, etc., or something else resulting in a new development of radiation problems happens?
Something could still go seriously wrong in the next months ahead, no?

Recently large earthquakes nearly under the DaiIchi nuclear power plant have been occurring daily.

Is this recent news about unit #4’s fuel pool related to the Mag. 7.1, or 6.0, or 5.6, or 6.3, or 5.8, or 5.5….+ many more earthquakes just in the last few days centered very close to the nuclear plant?
“Radiation has risen to high levels above the spent-fuel pool at reactor No. 4 and its temperature is rising,… indicating the fuel rods have been further damaged and are emitting radioactive substances.”
“The radiation level 6 meters above the spent-fuel storage pool at the crippled Fukushima No. 1 nuclear plant was measured at 84 millisieverts per hour Tuesday. Normally, it’s 0.1 microsievert.
The temperature of the pool was 90 degrees, compared with 84 before it caught fire on March 15”

Earthquake info:
This is the Japanese Meteorological Agency list:
This site is based on the USDS data:


OK, let me rephrase my original question on the Yablokov report:

Short description of the material: This is a 300+ page report originally published in 2007 in Russian.

It was translated and published in December 2009 by the NYAS. It examines the effects of the Tchernobyl accident accross a broad range of geographies and angles (public health, flora, fauna, etc.)

My judgement on its quality: This is a collection of scientific articles, which clear explanations on the methodologies used, including their limitations. It is backed by a bunch of data and references to related papers.

How it is relevant to the discussion: the level 7 rating “like Chernboyl” is about radioactivity levels and their potential consequences. This is the whole point of the report.

Chapter “3. General Morbidity, Impairment, and Disability after the Chernobyl Catastrophe” compares the desease rates in comparable populations before and after the accident. For example, the following diagram compares invalidism rates in Belarus areas heavily and less contaminated:

Such findings are particularly troubling, and I would love to read what medical experts think about that.


@Geoff Russell, on 14 April 2011 at 11:59 AM

None of your examples of “worse things” have anything to do with the INES rating.

You are quite magnanimous in your opinion of how the evacuees feel about their situation. They may feel otherwise.

From a political and public policy point of view the evacuation is worse than if a few dozen reactor workers were killed but without the need for evacuation. When there is an industrial accident, such as a refinery accident, society shakes it’s collective head and goes on, basically unaffected.

Any civilian deaths that might accrue from a reactor accident are statistical blips that occur years or decades later.

But mass evacuations are sure, certain, and very visible. There are few or no worse conceivable outcomes. I’m sure that is taken into account when the release levels assigned to level 7 were put to writing.

No other form of industrial accident has such a lasting effect on so many, and on a nation as a whole. Except maybe a worst case LNG explosion but that has never happened so we don’t know how society would/will deal with that.

The Shoreham plant fiasco was a result of, among other things, concerns that something like this could cause the more or less permanent evacuation of Long Island (or worse Manhattan). In that sense it is hard, in retrospect, to argue with the Shoreham antagonists.
This discussion is spilling over into the philosophical area. If you want to go on with this, please move over to the Fukushima Philosophical Open Thread where personal opinion not backed by refs etc is OK and the commenting rules are more relaxed.


@bored cynic : maybe it was a rethorical question ?

Anyway, here is the answer (from here : ) : first death is after 11 days, for an estimated received dose of 25 Sievert !

This being said, I don’t believe number of deaths is the appropriate metric here. Number of healthy years lost per person is more appropriate in my opinion. I have great confidence that this number is large for Chernobyl, but I have also great confidence that this number is dwarved by the cumulated effect of a health system which became derelict because of the mismanaged economy in the ex-USSR. I should add an incredibly high, and still ongoing, consumption of vodka and cigarettes.

I think people underestimate the health benefits of added prosperity afforded, inter alia, by cheap power and industrial production. When one is poor, even dirty coal or biomass energy seems a good bargain. When western activists tout “frugality” and “human scale production”, developping countries grind their teeth because they know it is a synonym of the “poverty” they have been living under and trying to escape from. It is the modern version of “let them eat cake”.


A bored cynic:

According to the Wikipedia account of the Chernobyl disaster, 2 deaths occurred immediately from the explosion itself (namely Vladimir Shashenok, who was crushed by debris, and Valerie Khodenchuk, presumed killed and crushed in the explosion itself – his body was never found, but it is believed to be buried somewhere in the Reactor 4 building). The bulk of the rest appear to have been in May, so we’re talking a period of perhaps a week to a month afterwards.

If you superimpose the Chernobyl disaster over the Fukushima event (given that it’s currently approximately a month and 3 days since the tsunami), 24 of the 31 people known to have died as a direct result of the accident would be dead by now.

So by that metric also, this disaster is a very different animal to the Chernobyl disaster.


@A bored cynic

“Curious. So many people here keep posting the death count comparisons between this and chernobyl. Anyone know how long after the accident at Chernobyl it was before the first deaths occurred?”

According to the UNSCEAR report ( ) the first deaths occured within the first four months(page 12 of the PDF document linked above)

However those deaths were due to acute radiation syndrome which hasn’t happened to anyone in Fukushima so i’m not sure this answers your question. The UNSCEAR report does not mention any timeframe for deaths other than those from ARS(at least i did not find one)


@charles monneron, on 14 April 2011 at 3:49 PM said:
“NR99 : “No other form of industrial accident has such a lasting effect on so many, and on a nation as a whole.”
I suggest you check the situation in Bangladesh or if you like official sources,

Charles, the intro to the WHO report you linked:

“Bangladesh is grappling with the largest mass
poisoning of a population in history because groundwater used for drinking has been contaminated with
naturally occurring inorganic arsenic…”

Emphasis mine. I referred to industrial (man made) accidents.

My original statement about the impact of the evacuation has been nit-picked several times here. It is obvious I struck a nerve. I am not anti-nuclear, but I would suggest that the pro-nuclear side needs to face this issue head on. Otherwise they and their anti-nuclear opponents will simply be talking past each other. And, based on the rather sparse construction starts for new nuclear plants of late, I’d say they are winning the battle of wits.

I was recently admonished by a mod for my defense of my original statement, suggesting my statement or my defense (not sure which) was philosophical and off topic to this thread.

It was not my intent to wax philosophical. My intent was simply to point out the political and real world practical side of the elevated INES 7 rating at the heart of this thread. This is my last word on the subject. Feel free to nit-pick my choice of words (that is apparently acceptable in this thread but not my defense) but ignore the message at your peril. And believe me, I’m on your side but I have a realistic view of these things. It’s not about arcane millisievert or becquerel measurements. It’s all about wholesale evacuations.


>> groundwater used for drinking has been
>> contaminated with _naturally_ occurring
>> inorganic arsenic…

> Emphasis mine. I referred to industrial
> (man made) accidents.

Your information was out of date as of late 2009.

The arsenic got into the drinking water through the wells put in 30 years ago. They are too close to the rice paddies. Water seeping down from the paddies extracted the arsenic; new wells brought it up.

“ScienceDaily (Nov. 16, 2009) — Researchers in MIT’s Department of Civil and Environmental Engineering believe they have pinpointed a pathway by which arsenic may be contaminating the drinking water in Bangladesh, a phenomenon that has puzzled scientists, world health agencies and the Bangladeshi government for nearly 30 years. The research suggests that human alteration to the landscape, the construction of villages with ponds, and the adoption of irrigated agriculture are responsible for the current pattern of arsenic concentration underground….”

“It’s a poor sort of memory that only works backwards” — Alice in Wonderland

Type what you believe into a search engine.
That will give you what’s new since you learned what you believe — something new most every day.

Then look for a consensus statement by people who’ve read it all and thought it through.



I was only responding to Charles’s link in the context of my “industrial accident” comparison. It was totally out of context of my statement, as presented in his link.

Even so, that later research is far from what I call an “industrial accident”. It would be very off topic to pursue this or the reasons for the Bangladesh problems.

I stand by my point that it is difficult at best to find industrial accidents that result in evacuations of entire cities. And that is at the core of the INES 7 rating and all the problems left to resolve at Fukushima.

I will forecast that the final end game could very well be a battle between strict adherents of LNT and those that believe in thresh-hold or hormesis. That will determine when the residents are allowed to return, and to some extent when they actually will return, given they will always have a choice based on what they can divine from public sources. And the result of that battle will determine the final INES rating that history puts on this event.
This is slipping into the philosophical -which is where these arguments are on-going, including LNT. Please post in the Fukushima Philosophical OT from now on.


@NR99: your looks to me a very focused and correct point, the future development of the Fukushima accident will have a deep impact both on LNT principle and on INES scale, imho


Atomic Power Review points out the obvious — water flows downhill.

“It seems as if TEPCO might have discovered what happened when the company essentially plugged up the Eastern facing, or downhill, end of the probably highly fractured facility grounds, pavement, substrate and foundations because there has been a spike over the last day and a half in activity in sub drain pits which seems to correlate to water that’s been through one of the reactors. We wondered before if this weren’t really the fix it seemed.. the public was very relieved that the spread into the water was cut down, but we were very interested to find out where this water would appear next given the essentially fixed flow rate into the reactors….”


So, is there a tech discussion thread here somewhere? I see no news the week I went camping. But poking around for a few hours, there seems to have been news worth mentioning somewhere.

“… authorities were looking for ways to shore up the bottom of the spent uranium fuel-rod storage pool at Reactor No. 4 to prevent it from collapsing….”

“TOKYO, April 17, Kyodo
The U.S. government has told Japan that it can use a U.S. unmanned cargo transport helicopter to set up cranes to remove spent fuel rods from storage pools at the crippled Fukushima nuclear power plant, Japanese and U.S. sources close to the matter said Saturday….”


“-From 11:43am to 0:50pm on April 21st, an unmanned helicopter flew over Units 1 to 4 to confirm the conditions around the building of those Units.”

what’s been happening?


Best news seems to still be over at

“…. we now have available a message from the Japan Nuclear Technology Institute that gives us a couple of mechanical hints. This letter, available at the JANTI site is really intended to be a stern admonishment to the senior nuclear establishment in Japan (primarily the NSC) to get on-site and get contributing….
… What we’re trying to do here is take the few new facts we’ve been given, and start down the path to understanding those critical 24 to 48 hours in which the whole situation at Fukushima Daiichi turned from unusual event to accident. We will provide updates and corrections to the information as new data appear.
1:00 PM Eastern Wednesday 4/20”



Much detail:

Click to access status1F.pdf

Status of Fukushima Daiichi Nuclear Power Station As of 8:30 Apr.21, 2011

This (Written on April 11, 2011) reads like a dope slap — meant to get attention.
“… I have outlined the current status, concerns and reflections surrounding the nuclear power station based on information updates of this incident. Scrutinizing the incident in further detail is the task ….”


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