Meltdown at Fukushima

Written By: - Date published: 8:39 am, March 31st, 2011 - 35 comments
Categories: disaster - Tags: ,

Efforts to cool the nuclear fuel rods in Fukushima’s No 2 reactor have failed. The rods have become molten and it appears some have melted through the steel reactor core into a concrete layer. Two dangers now arise: radioactive chemicals created by the concrete reacting with the nuclear fuel and the nuclear fuel pooling enough to go critical.

This is what ended up happening to the nuclear fuel in Chernobyl’s No 4 reactor. Lava-like ‘corium‘, which is just a fancy name for ‘substance made from the molten core of a nuclear reactor’, melted through the steel liner and solidified in what was called the ‘elephants foot’ on the concrete basement floor*. The fuel melted through several metres of concrete, creating hydrogen gas and other volatile substances.

Ironically, the water they’re desperately trying to get into the reactors at Fukushima to carry away the heat actually helps to sustain nuclear reactions by slowing down (moderating) the neutrons emitted when an atom decays making them more likely to collide with other unstable atoms. Without the water and with all the reactions with concrete the melting ends. The corium gradually solidifies into what becomes a flaky and still highly radioactive material.

We’re still told that there won’t be a major radiation release from Fukushima as there was from Chernobyl. During that disaster, a graphite fire and multiple explosions after the core was breached sent corium and other irradiated materials high into the atmosphere to be distributed over a wide area. There’s not meant to be any more explosions at Fukushima. They say they are confident they can cool the corium as it comes out.

But a hell of a lot of stuff that wasn’t meant to happen has happened. If the corium is reacting with the concrete creating large amounts of hydrogen and carbon monoxide, then explosions are a real possibility. If the corium comes out all as one glob it could go critical, recreating the self-sustaining chain reaction that powers a nuclear reactor when it’s in action. That’s a hell of a lot more energy then is currently being emitted by the background decay of the fuel rods, which has been enough to cause all these problems. The one bright side is there’s no way it can go supercritical and explode like a nuclear bomb.

It’s not just No 2 reactor. Plutonium has been detected around reactor No 3. This reactor uses MOX fuel, containing plutonium, which is really dangerous stuff. The fact that plutonium seems to be leaking from the reactor suggests a breach in its core too.

With radiation levels rising, it is becoming both evermore vital and evermore difficult for workers to get close to the reactors to try to solve the problems.

I hope they’re drawing up plans for a sarcophagus, and not one like Chernobyl’s that started leaking after a few years.

35 comments on “Meltdown at Fukushima ”

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  1. Colonial Viper 1
    31 March 2011 at 8:51 am

    🙁

    Damn none of that sounds good.

    There is an economic fear as well – that if this whole scenario drags on for months, which it might, business interests will start to bypass Japan altogether. Find alternative suppliers, find alternative ports, offshore operations etc.

  3. Morrissey 3
    31 March 2011 at 9:30 am

    But just over a week ago I saw Air New Zealand boss Rob Fyfe on television, and he was adamant: the fuss over so-called nuclear leaks was a beat-up, and there was nothing to worry about. He advised us to do as he did, which was to accept the word of the Japanese government’s PR people, and not to trust the word of so-called “experts”.

    Here’s a picture of the great man, characteristically deep in thought…
    http://www.iata.org/iata/sites/agm/2009/file/agm2009-02.jpg

    • Lanthanide 3.1
      31 March 2011 at 10:09 am

      He was, and remains, correct.

      There is no danger to aircraft flying to Tokyo, and funnily enough the pilots are actually smart enough to fly around the contaminated area as well.

      • Morrissey 3.1.1
        31 March 2011 at 10:27 am

        “…no danger to aircraft flying to Tokyo…”
        Could you advise us of the source from which you obtained this highly interesting piece of technical information? (Note: Mr Rob Fyfe is not a credible or respected source.)

        • Colonial Viper 3.1.1.2
          31 March 2011 at 12:23 pm

          The thing is, unless you are flying directly over a concentrated gamma ray source, you will be fine at 32,000 feet. In fact at that altitude you could have a 100kT warhead go off a few miles away and still be relatively fine.

          The main issue to me is not whether people can still fly in and out of Tokyo. It will be whether or not they want to.

  4. Lanthanide 4
    31 March 2011 at 9:32 am

    As usual, the media reporting on the plutonium that was detected isn’t very detailed, and so it appears much worse without the detail included:

    “Vienna. Japan Confirms Plutonium in Soil Samples at Fukushima Daiichi. After taking soil samples at the Fukushima Daiichi nuclear power plant, Japanese authorities today confirmed finding traces of plutonium that most likely resulted from the nuclear accident there. The Nuclear and Industrial Safety Agency told the IAEA that the Tokyo Electric Power Company (TEPCO) had found concentrations of plutonium in two of five soil samples.

    Traces of plutonium are not uncommon in soil because they were deposited worldwide during the atmospheric nuclear testing era. However, the isotopic composition of the plutonium found at Fukushima Daiichi suggests the material came from the reactor site, according to TEPCO officials. Still, the quantity of plutonium found does not exceed background levels tracked by Japan’s Ministry of Education, Culture, Sports, Science and Technology over the past 30 years.”

    In other words they found very minute traces of plutonium. Also, plutonium is dangerous to human health because it’s a very toxic material (like arsenic or other heavy metals), rather than because it’s radioactive.

    Plutonium fission products are found in all of the spent fuel rods as a result of fission in the reactor. It’s minute amounts, however. The MOX fuel in reactor 3 is being overplayed – there are something like 700-800 rods active in there at any one time, and only a couple of dozen actually have MOX fuel (which again is only 5% plutonium) and the rest are regular uranium.

    • Morrissey 4.1
      31 March 2011 at 9:41 am

      Lanthanide, these figures of yours are meant to reassure or comfort? How, exactly?

      • Rich 4.1.1
        31 March 2011 at 9:58 am

        Maybe you should just take the Lewis Page approach:
        – Fukushima isn’t a disaster. Chernobyl wasn’t a disaster. The backup safety systems have worked as designed. Look, there are no people dying in the streets of Tokyo from acute radiation sickness – things are as designed.

        (And BTW, Plutonium isn’t dangerous because its a toxic heavy metal, but because it’s an alpha-emitter that accumulates in the body. Arsenic (which isn’t a heavy metal, or indeed a metal of any kind) doesn’t do that).

        • Lanthanide 4.1.1.1
          31 March 2011 at 10:19 am

          Reading about plutonium on wikipedia, it looks like you’re correct, the danger is more from radiation than specifically from toxicity, although it appears the danger is generally overstated:

          “A commonly cited quote by Ralph Nader, states that a pound of plutonium dust spread into the atmosphere would be enough to kill 8 billion people. However, the math shows that only up to 2 million people can be killed by inhaling plutonium. This makes the toxicity of plutonium roughly equivalent with that of nerve gas.”

          “There were about 25 workers from Los Alamos National Laboratory who inhaled a considerable amount of plutonium dust during the 1940’s; according to the hot-particle theory, each of them has a 99.5% chance of being dead from lung cancer by now, but there has not been a single lung cancer among them.”

          As for arsenic:
          “Arsenic is a metalloid. It can exist in various allotropes, although only the grey form is industrially important. The main use of metallic arsenic is for strengthening alloys of copper and especially lead (for example, in automotive batteries).”

          But no, it’s not a “heavy metal”, so I was wrong on that.

          • Rich 4.1.1.1.1
            31 March 2011 at 11:06 am

            I was under the impression that you Knew About All Things, and now I hear you just repeat Wikipedia and the PR department of a japanese airport?

            • ianmac 4.1.1.1.1.1
              31 March 2011 at 11:12 am

              Unworthy of you Rich.

              • Rich …
                31 March 2011 at 3:01 pm

                I’m fed up with this attitude that nuclear power is a safe answer to all our problems and that anyone who opposes it is a luddite scientific ignoramus.

                I understand the pathology. People in the geek community read and watch far too much scifi. Scifi as an artform was developed in 1950’s America, where technology was going to lead us to a bright new future with flying cars and synthetic clothing. So when we have a problem (such as peak oil/climate change) a “technical” solution must arise. Nuclear power is that technical solution, and must be made to succeed.

                Hence, actual problems that prevent nuclear power being deployed get magicked away. Safety limits get questioned – hey look, 25 people got a big dose of Pu and didn’t die – that means it’s safe, right? New technology gets pulled out of a hat that will never, ever have the problems of Fukushima (as Fukushima wouldn’t have the problems of Chernobyl, and Chernobyl wouldn’t have the problems of Windscale Pile I).

                So if people who claim to have scientific evidence for the safety of nuclear energy make schoolboy errors (we did the classification of elements in 5th form), I’m going to call them on it. Sorry, and that.

                • Colonial Viper …
                  31 March 2011 at 3:24 pm

                  No, nuclear power is not some kind of SF solution to all energy needs. But it’s been around as a working concept since the days of the Korean War.

                  There is no doubt that when nuclear power goes bad, it can go very bad.

                  And both regulators and private enterprise seem keen to cut corners which should not be cut.

                  But there are very simple steps which can be taken to limit the damage and probabilities of even a worst case scenario.

                  TEPCO should not have been allowed to store such huge amounts of spent fuel on site, at the densities which were there. A higher sea wall and diesel generators/back up power systems capable of surviving a drowning would both have been extraordinarily helpful. Not having 6 reactors at one site.

                  At the end of the day a lot of important corners were cut, usually in the name of reduced cost and increased efficiency.

                  • mcflock …
                    31 March 2011 at 4:41 pm

                    Agreed, CV. And to me, that’s the real danger of nuclear power – complacency.

                    It’s all very well saying that modern designs are safe now, but what about in 60 years when the workforce has been whittled down in quality or quantity by HR cost-cutting, emergency plans have atrophied, bypass repairs have been left as the norm, waste has built up beyond spec (sorry, “according to re-evaluated and expanded specifications”), etc etc etc? In many accidents/mishaps, it’s not when something is new and shiney that the problem occurs – it’s when a routine job being performed by junior staff at 3am goes kaput that the clusterfuck begins.

        • toad 4.1.1.2
          31 March 2011 at 10:29 am

          Technically, arsenic is a metalloid, being to the left of the amphoteric line in the periodic table. As such, it displays some of the properties of metals, but it is certainly not a heavy metal.

          And you are right, Rich, about the difference between the toxicity mechanisms of plutonium and arsenic. While they are both bio-accumulative, plutonium’s high toxicity is because of the carcinogenic effect of the alpha-particles it emits in radioactive decay. Arsenic’s toxicity arises from its interference with metabolism through disrupting ATP production.

          • NickS 4.1.1.2.1
            31 March 2011 at 2:09 pm

            Not entirely, if memory serves me right, elements like plutonium and uranium when in soluble forms will form ionic bonds (aka co-ordination chemistry) to a wide variety of biomolecules, disrupting metabolic and cell functions depending on what they bond to. Although it appears from accidental inhalation and ingestion that Pu is very considerably less toxic the U-238, but it’s also, despite it’s sort half-life, does not appear to increase cancer risks.

            Still not something you’d want to inhale/ingest, but compared to it’s decay products, it’s far less biological and radiologically dangerous.

            And yeah, arsenic is toxic due to being very electrochemically similar to phosphate, allowing for it to replace it in key phosphorylated biomolecules, where unlike phosphate it ends up binding far more strongly in the active sites of enzymes in the Krebs Cycle.

  5. The Economic Illiteracy Support Group 5
    31 March 2011 at 10:58 am

    For anyone interested in how bad things are becoming at Fukushima, I can heartily recommend the IAEA’s nuclear accident update log – good information, no commentary from “experts” – or worse, interpretation from journalists who don’t seem qualified to interpret nuclear meltdowns. It does mean you need to draw your own conclusions about the future direction of the reactors, but I have to say that I’m concerned that most of the worst-case scenarios do seem to have eventuated.

    • ianmac 5.1
      31 March 2011 at 11:11 am

      Thanks EISG. Thank goodness that the information therein seems credible and nearly understood by a Bear with very Little Brain. Still worthwhile to grapple with the discussion above.

    • Lanthanide 5.2
      31 March 2011 at 11:27 am

      I have seen videos of ‘experts’ on you tube saying they got data from the IAEA. But that data isn’t publicly available on their website. One video I saw was talking about radiation rates observed the area north-west of Japan, which has since been made publicly available only in the last couple of days or so.

      So while the IAEA is one of the best sources to go to, it seems that they aren’t publishing everything, and that some experts and other agencies may actually have an ‘inside run’ on the latest developments.

      • The Economic Illiteracy Support Group 5.2.1
        31 March 2011 at 11:42 am

        I’ve noticed that the data appearing on the IAEA site is slower to come out than in the mainstream media – so I don’t think they’re withholding anything, but their turnaround cycle on the website is definitely slower than in the general media. I’m tending to read the MSM reports with a degree of skepticism until the IAEA provides a more accurate view a day or two later. YMMV.

        • Bright Red 5.2.1.1
          31 March 2011 at 11:45 am

          “The International Atomic Energy Agency said safe limits had been exceeded at Iitate village, 40km northwest of Fukushima, well outside the government-imposed 20km exclusion zone and the 30km “stay indoors” zone.

          “The first assessment indicates that one of the IAEA operational criteria for evacuation is exceeded in Iitate village,” the IAEA’s head of nuclear safety and security, Denis Flory, told reporters.”

  6. freedom 6
    31 March 2011 at 1:02 pm

    The USO said about 200,000 U.S. personnel are being evacuated from Japan to U.S. West Coast cities including San Diego, San Francisco, Los Angeles and Seattle/JBLM.

    http://www.kirotv.com/news/27248974/detail.html

    http://uncensored.co.nz/2011/03/25/stuxnet-japan-division/

    As always there is more to the stories than the scraps we are fed yet 200,000 personnel is most definitely news and most definitely is not being reported in the msm

    as a comparison, it would be like announcing the withdrawl of all military servicemen and private contractors out of Iraq

    • Lanthanide 6.1
      31 March 2011 at 1:22 pm

      The Americans are always over-cautious and paranoid about this sort of thing, though. Look at all the fear whipped up by three mile island.

      I also wonder about the numbers in the first article. At the start it talks about 15,000, and says that 6,700 and 8,000 have arrived at specific basis. At the bottom out of nowhere it suddenly says 200,000. I wonder if that’s a typo or something and it really should be 20,000?

      I also think if 200,000 people had moved out of Japan, we’d know about it. The sheer number of flights and ships required to move that many people within the course of a month is mind-boggling. This article was posted 10 days ago and yet nothing more has been mentioned anywhere about it. Doesn’t add up.

      I checked the http://www.usopsa.org website mentioned in the article. There’s no mention of this evacuation on the site, and the press releases haven’t been updated since 2010.

      As for the stuxnet thing, that’s pretty much tin-foil hat territory. Evidence for stuxnet points firmly at US and Israeli government agents writing viruses specifically to target the equipment used in Iranian centrifuges and fuel enrichment centres. I read an article a couple of months ago that said new evidence indicates that the stuxnet virus was disrupting Iran’s nuclear programme about a full year before it became public knowledge.

      The nuclear power plants in Japan that are currently having issues are far removed from the equipment used to enrich nuclear fuel in Iran, and probably aren’t even made by the same manufacturer. Stuxnet was also a deliberate attack on Iran, it seems unlikely it could make its way to Japan through any other than deliberate means, which again is unlikely.

      • freedom 6.1.1
        31 March 2011 at 1:40 pm

        i posted the uso story to see if anyone else had heard or knew of any other data as i was having trouble finding confirmation, ( which in itself these days is hardly a reason to disbelieve anything.)

        the stuxnet issue is a little more interesting as the plant uses Siemens gear and there are reports of stuxnet affecting many machines outside of Iran. The growing theory is not that the stuxnet caused the fault because as we all know it was the Tsunami that damaged the plant, what is being suggested is that the Siemens/Stuxnet problems the plant was already experiencing may have affected the plant’s ability to function properly

  8. joe90 8
    31 March 2011 at 3:29 pm

    News that an actual meltdown may be under way and the president of TEPCO playing where’s Wally, worrying.

  9. joe90 9
    31 March 2011 at 4:31 pm

    Dr. A. Gopalakrishnan, former chairman of the Atomic Energy Regulatory Board in India speaks about the ongoing problems with the Fukushima reactors

  10. Draco T Bastard 10
    31 March 2011 at 5:53 pm

    Dangerous Levels of Radioactive Isotope Found 25 Miles From Nuclear Plant

    The isotope, cesium 137, was measured in one village by the International Atomic Energy Agency at a level exceeding the standard that the Soviet Union used as a gauge to recommend abandoning land surrounding the Chernobyl reactor, and at another location not precisely identified by the agency at more than double the Soviet standard.

    The measurements, reported Wednesday, would not be high enough to cause acute radiation illness, but far exceed standards for the general public designed to cut the risks of cancer.

    Seems to be getting even worse as time goes by.

  11. Peter 11
    31 March 2011 at 6:12 pm

    FUKUSHIMA NUCLEAR RADIATION IS FOREVER.

    http://www.indybay.org/newsitems/2011/03/27/18675697.php

    http://www.marketoracle.co.uk/Article27229.html

    Japan downplaying the Ionizing Radiation for so many days is scandalous and
    tantamount to global genocide.

  12. RedLogix 12
    31 March 2011 at 7:00 pm

    The crucial point no-one wants to face up to is that everyone of the 450 odd BWR or PWR reactors currently operating in the world are vulnerable to exactly the same failure mode, loss of power to the cooling pumps for a period long enough to compromise fuel integrity.

    Which depending on the exact operating conditions at the time, can be a remarkably short period.

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