Guest Post: Japan Considers Raising Nuclear Disaster from Level 5 to 7 Based on Extremely High Radiation Readings

Washington’s Blog

As I wrote on March 29th, radioactive cesium levels from Fukushima already rival Chernobyl, and a study conducted by a team of experts from Kyoto University and Hiroshima University found extremely high levels of cesium outside of the 30 kilometer evacuation zone:

[A] study was conducted by a team of experts from Kyoto University and Hiroshima University … found cesium-137 at levels between about 590,000 and 2.19 million becquerels per cubic meter [outside the 30 kilometer evacuation zone].

After the Chernobyl nuclear accident in the former Soviet Union in 1986, residents who lived in areas where cesium-137 levels exceeded 555,000 becquerels were forced to move elsewhere.


The amounts of cesium-137 found in Iitate were at most four times the figure from Chernobyl.

If more radioactive materials are emitted from the crippled Fukushima plant, the level of cesium-137 could rise even further.

Today, In the department of the obvious, Kyodo News is reporting that – due to extremely high radiation levels – the Japanese government is considering raising the nuclear crisis from a 5 to a 7 – the highest possible level of disaster:

The Nuclear Safety Commission of Japan released a preliminary calculation Monday saying that the crippled Fukushima Daiichi nuclear plant had been releasing up to 10,000 terabecquerels of radioactive materials per hour at some point after a massive quake and tsunami hit northeastern Japan on March 11.

The disclosure prompted the government to consider raising the accident’s severity level to 7, the worst on an international scale, from the current 5, government sources said. The level 7 on the International Nuclear Event Scale has only been applied to the 1986 Chernobyl catastrophe.


According to an evaluation by the INES, level 7 accidents correspond with a release into the external environment radioactive materials equal to more than tens of thousands terabecquerels of radioactive iodine 131. One terabecquerel equals 1 trillion becquerels.

Haruki Madarame, chairman of the commission, which is a government panel, said it has estimated that the release of 10,000 terabecquerels of radioactive materials per hour continued for several hours.

The commission says the release has since come down to under 1 terabecquerel per hour and said that it is still examining the total amount of radioactive materials released.

As I noted yesterday:

The Japanese government reports radiation levels in the number 1 reactor of at least 100 sieverts per hour:

In contrast, radiation levels were apparently about 300 sieverts per hour – 3 times higher – right after Chernobyl exploded.

As MIT explains, the reason that different units for measuring radiation are so confusing is that the U.S. uses a different system from metric countries and different units measure different things:

There are a number of reasons for the confusion. In part, it’s the usual disparity between standard metric units and the less-standard units favored in the United States, added to the general confusion of reporters dealing with a fast-changing situation (for example, some early reports mixed up microsieverts with millisieverts — a thousandfold difference in dose). Others are more subtle: The difference between the raw physical units describing radiation emitted by a radioactive material (measured in units like curies and becquerels), versus measurements designed to reflect the different amounts of radiation energy absorbed by a mass of material (measured in rad or gray), and those that measure the relative biological damage in the human body (using rem and sieverts), which depends on the type of radiation. (Rem, rad and gray are all used as the plural as well as the singular form for those units).

In other words, becquerels measure radiation emitted while sieverts measure biologic damage to the human body. That is why one measure can’t be converted into the other … they measure different things.

Figures on Chernobyl radiation are a little harder to come by in becquerels. But New Scientist noted last month:

In the 10 days it burned, Chernobyl put out 1.76 × 1018 becquerels of iodine-131, which amounts to only 50 per cent more per day than has been calculated for Fukushima Daiichi….

Similarly, says [Gerhard Wotawa of Austria’s Central Institute for Meteorology and Geodynamics in Vienna], caesium-137 emissions are on the same order of magnitude as at Chernobyl. The Sacramento readings suggest it has emitted 5 × 1015 becquerels of caesium-137 per day; Chernobyl put out 8.5 × 1016 in total – around 70 per cent more per day.

1.76 × 1018 becquerels of radioactive iodine over 10 days equals 7.33 × 1015 becquerels per hour during the fire at Chernobyl.

Similarly, 8.5 × 1016 becquerels of radioactive cesium over 10 days equals 3.54 × 1014 becquerels per hour during the fire at Chernobyl.

Both Chernobyl and Fukushima have also released radioactive strontium, called strontium 90. The Nuclear Regulatory Commission estimates:

As a result of the Chernobyl accident, approximately 216,000 curies of Sr-90 were released into the atmosphere.

This is the amount released over the entire time the Chernobyl reactor leaked. 216,000 curies equals 7.992 × 1015 becquerels. Being conservative, and assuming that all of the strontium was released during the initial 10-day fire, results in an hourly strontium release of 3.33 × 1013 of becquerels of strontium 90 per hour.

7.33 × 1015 plus 3.54 × 1014 plus 3.33 × 1013 equals 7,717,300,000,000,000. In other words, Chernyobyl put out an average of 7.717 times 1015 becquerels per hour of radioactive iodine and cesium during the fire.

In contrast, Fukushima put out 10,000 terabecquerels per hour of radioactivity for at least a couple of hours. 10,000 terabecquerels equals 1 x 1016 becquerels, more than Chernobyl.

The above back-of-the-envelope calculation is not definitive, because there were some other (although less important) radioactive materials were also released from Chernobyl, and because the Japanese government has not released enough information to make a definitive comparison.

But the bottom line is that – as even the Japanese government is now reluctantly being forced to admit – the amount of radioactivity being released from Fukushima appears to rival Chernobyl.

Update: The Japanese government has in fact decided to raise the crisis level to 7.

Update 2: Tepco is finally admitting what has been obvious for some time: that Fukushima could end up being worse than Chernobyl.

As Reuters notes:

The operator of Japan’s crippled Fukushima Daiichi nuclear power plant said on Tuesday that they are concerned that the radiation leakage could eventually exceed that of the 1986 Chernobyl nuclear disaster.

“The radiation leak has not stopped completely and our concern is that it could eventually exceed Chernobyl,” an official from operator Tokyo Electric and Power told reporters on Tuesday.

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    1. gepay

      I can’t remember where I saw it but my memory tells me the strontium was about 1/10 of the cesium. I don’t remember if that was Sr90 or Sr90+Sr89. Sr 90s halflife (28.78 yrs) is very similar to cesium 137 while Sr89 (50.57days)is quite a bit shorter. SR90 fission yield of U235 is 5.8% Chernobyl probably did get a lot hotter than the meltdowns of Fukushima. I believe there have been transient criticalities also at Fukushima.
      I have been wondering why no Sr has been detected or if not why they aren’t putting Sr90 ND – not detected. radioactive Krypton 89 does decay to Sr 89 also. they are making no attempts Apparently much more strontium 90 is distributed by open air atom bomb tests because of its relatively high volatility. I imagine that with the same amounts Cs137 and Sr90, Sr90 would be more dangerous as it preferably collects in the bones whereas Cs would anywhere in the body that K is used.

      You might like this chart although not about Sr.
      Table 8: Global Collective Doses From Anthropogenic Radiation Sources
      Source of Exposure Global collective dose (Person-Sv)
      Chernobyl Accident 600,000
      World Nuclear Power Production to 1989 400,000
      World Radioisotope Production and Use to 1989 80,000
      La Hague (planned operation 2008-2025) 65,000
      World Nuclear Weapons Fabrication to 1989 60,000
      Kyshtym Accident USSR 1957 2,500
      Windscale Accident UK 1973 2,000
      World Underground Nuclear Testing to 1989 200
      Three Mile Island Accident US 1979 40
      Sources: derived from Bennett (1995)80; UNSCEAR (1993)81 and UK HPA / CEPN (2006).82
      You might try contacting the Idealist who has done much research on the dangers of radioactive fallout.
      I saw that NHK broadcast where they said radioactive water was leaking into #5 and #6 (turbine halls, ) but have not seen a thing more about it.

  1. ambrit

    Given the abandonment zone established around Chernobyl, and that the reactors there were far inland, doesn’t the situation of Fukushima on the littoral suggest that this won’t be anywhere near as ‘easy’ to contain?
    And since this is, after all, Japan, can Godzilla be far behind?

  2. SteveA

    The Japanese government needs to publish the cumulative radiation totals, broken out by radionuclide. Giving a peak for ‘several hours’ and the current, apparently minimum rate, is meaningless. For all we know, after hitting a max of 10PBq/hr, it may have ranged at 8PBq/hr for hours afterward.

    Also, the notation in this post needs to be fixed — the exponentiation marks are missing.

  3. Van Allen Belt

    Low levels in US drinking water and milk which means every TBTF Bank is swimming in protons that are just looking for a home. To the Hague!

  4. scraping_by

    Thanks for answering a big question.

    In a lot of the science-free science reporting of the MSM, there’s talk of “radioactive water” pouring into the ocean. They then compare it to all the water in all the oceans in the world. Cute.

    In reality, radioactive elements are carried, dissolved or suspended, into the ocean, where they are carried by the Pacific currents eastward. Some will drop out of the water, but they’ll hang around, hot, for a long time. Except for some experiments in vitrification, all molecules keep circulating.

    Unlike the dishonest comparisons to the momentary exposure from cell phones and CT scans, this stuff gets taken up in living bodies, ours or our food, and becomes a source of damage until and unless it’s expelled or it decays to a low level. Our immune systems may handle the damaged tissue, or it may not. If not, then we’re sick.

    Anyway, the debris from the Japanese coastal towns is showing up in California. While we won’t get the dark clouds laced with Plutonium Western Europe got during Chernobyl, what we will get will serve.

  5. Sleeper

    Has anyone noticed that the large Utility companies are keeping their heads down ?

    Not a peep frpm GE or Areva(sp) either.

    Looks like another exercise in extend and pretend.

  6. molten_tofu

    Unless I’m mistaken “only 50% more” doesn’t sound like much of a difference day to day, but over 10 days it’s 1.5^10, and that’s 60x in favor of chernoybl.

  7. alain maronani

    As a leading french green leader says yesterday……and it summarizes very well the tragedy unfolding here….

    I quote

    “There is NO after following a nuclear reactor disaster”.

    For Areva and GE they will have to review theirs business plans…

  8. acontra

    Wow. A couple of petabecquerels here, a couple of petabecquerels there, pretty soon you’re talking about some real radation.

  9. James Brooks

    Right, scraping_by, many of those emitter particles do travel a long way before coming to rest. Quite possibly in some living thing. Like the probable trillions of 1 to 5 micron particles of depleted uranium we’ve cast to the winds of Iraq, Afghanistan, the Balkans, Libya, sowing robust clusters of cancer, leukemia, and birth defects as we go. However, there’s been a change in the wind. Now it’s our turn.

  10. Pro Nuke Power Bloke

    Some talking points you might want to consider before you hastily conclude that nuclear power is not safe:

    *Nuclear power accidents are rare. They happen less than every 30 years.

    *When not subjected to abnormal weather or acts of god, they only emit a very small amount of radiation.

    *Coal, oil and gas will kill more people than Fukushima and Chernobyl combined, especially when we have to fight wars to get them.

    *Fukushima is a marvel of engineering, in that it withstood a big earthquake and tsunami

    *There is electrical power to Fukushima now, which is a hopeful sign.

    *I will wave my hands, confuse you, and then tell you it’s not as bad as Chernobyl. You will believe me because I speak with an air of authority.

    *The minute amount of radiation that will make its way around the world is not dangerous given that the EPA raised its standards for defining dangerous.

    This has been a public service message by the trolls who visit this blog.

    1. PghMike

      All true, but it *is* possible to build safer reactors; for example, reactors that can passively cool themselves during a station blackout. Given the seriousness of a failure, it seems prudent to transition to safer designs.

      1. Salviati

        Its amazing the faith that people put in the hands of scientists. Who is determining the aspects of safety when you are dealing with something like fission?
        Seriously, how many people do you know that are able to assess the safety of a nuclear power plant?
        Ultimately we have to rely on the very institutions that have a vested interest in seeing these things built.
        Notice, I haven’t even factored in the fact that these monstrosities are expensive to build. Most of it is done by private entities whose primary objective is to make a profit. So given that meltdowns are low frequency events, they will cut corners thinking that the hell will be paid by their successors. This is the real world, not some fantasy drawn up by the fools who believe that nuclear is the solution to our carbon issues. Truth is, even this is irrelevant.

        There is a very basic criteria to rule out nuclear power plants, namely that if the low probability event of a meltdown happens then the severity of the event is not containable. That’s it, end of story.

        1. Hal H

          The reporter Matthew Wald (NYTimes) was on NPR Fresh Air (mar 31rst) and offered a nice review of power plant nuclear accidents. He also has a piece today talking about the expected or target rate of accidents where emissions travel off site, as much as once every 3 years given the current number of plants (and toughest assumptions) vs. the preferred target rate.

          About being in the hands of scientists/engineers. In our modern life in cities, almost everything is.

        2. Name (required)

          So to a great extent the problem is not nuclear fission, it’s the need to make a profit from it which leads to cutting corners and the provision of safeguards against once in 50-year events rather than once in 500-year ones. So let’s remove the profit motive. Let’s have nuclear power-stations built by Governments with bottomless taxpayer purses to design for and properly implement safeguards against even once in 10,000-year events. Of course the power produced will be hugely expensive per kWh, so this has to be subsidised by the tax-payer to make it affordable by the taxpayer, at the expense of education, health, pensions, other infrastructure &tc. No, that’s silly. Scrap nuclear generation altogether.

          Of course thermal power stations, coal or oil, create pollution which is currently not factored into the cost per kWh to the consumer and is doing the environment no good at all. Making generators include the clean-up costs in the price of power would make it unaffordable to the taxpayer so let’s have the Government run all the thermal power-stations with an unavoidable mandate to somehow do it recapturing all the carbon and causing no environmental damage. Of course the power produced will be hugely expensive per kWh, so this has to be subsidised by the tax-payer to make it affordable by the taxpayer at the expense of education, health, pensions, other infrastructure &tc. No, that’s silly. Scrap thermal generation altogether.

          There’s always wind, solar, hydro and hydro-thermal. The first three can be unreliable so has to be considerably over-engineered to produce sufficient power in the good times to compensate on the bottom line for the bad, all are unwelcome practically everywhere by people who don’t want it in their backyard, are still relatively inefficient and are limited to sites with particular properties. Hence private generators don’t see much profit in it so it will have to be done by Governments who the power to ram it through local objections and the bottomless taxpayer purse to provide enough to meet demand even at night and when the wind isn’t blowing. Of course the power produced will be hugely expensive per kWh so this has to be subsidised by the tax-payer to make it affordable by the taxpayer, at the expense of education, health, pensions, other infrastructure &tc. No, that’s silly. Green energy will only work for small highly local schemes for folk who don’t mind not watching TV if the wind isn’t blowing.

          Of course there’s always…. Oh. No, there isn’t.

          1. Hal H

            “Of course there’s always…” er, well, potent conservation stuff, like new buildings using 1/4th (or less) the power of old, and…not so glamorous stuff like a dam operator buying cheap wind power at night to pump water back uphill to sell at peak, or a large building in Texas/Florida buying cheap wind power at night to cool a water tank to pre-cool A/C during the heat of the day, etc., stuff that doesn’t require new tech. It comes down to whether you think it’s possible to do things, or that nothing new can be done, etc.

    2. psychohistorian

      As a statement to the “effectiveness” of the current media, go out on a street corner today and ask 10 people what they know about the Fukushima situation and if they are aware at all they will most likely say that it looks like it is under control.

      Will we get to point where reality overwhelms that produced by the media? I hope that it is sooner rather than later. There is a lot of reality to discuss world wide.

    3. Tao Jonesing

      One of the reasons I lurk more and comment less at Naked Capitalism is the obvious presence of paid shills in the comments section.

      On the one hand, this development is a testament to Yves’ effectiveness.

      On the other hand, it is sad.

  11. Hal H

    NYTimes: “Japan’s Nuclear and Industrial Safety Agency said at a news conference Tuesday morning that the rating resulted from new estimates by Japan’s Nuclear Safety Commission that suggest some 10,000 terabecquerels of radiation per hour was released from the plant into the environment for several hours in the aftermath of the March 11 earthquake and tsunami. (The measurement refers to how much radioactive material was emitted, not the dose absorbed by living things. )

    The scale of the radiation leak has since dropped to under 1 terabecquerel per hour, the Kyodo news agency said, citing the commission. Commission officials in Tokyo said they could not immediately comment.”

    Interesting, because since all of this suggests that the emissions from the spent fuel pool at building 4 might have been quite large, having the current rate decrease from that maximum by a factor of 10,000 may be *only* what was ultimately meant when our DOE Sec. Chu (also Nobel physicist) said it was understood the pools were “under control” (nicely ambiguous)….

    Under control as in no longer emitting at that rate, being instead a matter of catching a lot into water, to be dealt with (or not) later.

    1. Hal H

      So far, the conditions at Daiichi have been relatively favorable compared to Chernobyl — no lasting fire creating ash particles to transport radionuclides more effectively. It appears to me they have a lot of stuff in water there, a modest bit dumped in the ocean, and some nasty airborn stuff from earlier (likely during the two fires at building 4) pushed northwest by wind at a bad moment. That would account for the contamination to the northwest. It appears we’ve been lucky, altogether, so far.

      1. Rex

        “It appears we’ve been lucky, altogether, so far.”

        Ha HA! — Nice gallows humor.

        May you live in interesting times.

        1. Hal H

          What are you afraid of, yourself?

          Do you live near Daiichi, or some repeated-problem (ill maintained) BWR?

          Do you think the typical American exposure of about 6 millisieverts/yr is gonna do you in?

  12. SteveA

    An hour ago, a NISA spokesman said during a news conference that the cumulative releases from Fukushima are 10% of those at Chernobyl.

    Right now, Kyoto News is running this: NEWS ADVISORY: Radiation leak may exceed amount in Chernobyl accident: TEPCO (12:09)

    So NISA and TEPCO can’t even agree on the numbers and severity. What a grotesque spectacle.

  13. razzz

    Remembering, there is a big difference between capitalists and free markets, these alternative energies don’t go ahead unless there is government approval, enter the lobbyists combined with corrupted politicians. Company’s don’t further themselves without enriching just the right entities in powerful positions.

    Do really think you couldn’t survive on 12volt house lighting? Or a roof on a house can’t be shingled with high tempered glass or every house can’t be roofed with solar and hot water panels? Or a house can’t be wrapped and insulated to where heating and cooling are minimal? Some entity will have to go broke for these things to happen.

    If competition is dead, so is progress unless thinking X4 crippled nuke plants are just an anomaly that will only temporarily dent your lifestyle, then it’s just a bump in the road to prosperity.

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