Symposium Q&A: Explosion at Fukushima Unit 3 drove nuclear fuel out of storage pool — Scattered up to 2 miles away (VIDEO)

Published: March 27th, 2013 at 4:45 pm ET


Source: The Medical and Ecological Consequences of the Fukushima Nuclear Accident, Day 1
Author: The Helen Caldicott Foundation
Date Presented: March 11, 2013

Questions & Answers

Arnie Gundersen, Fairewinds Energy Education: Unit 3 started as a hydrogen explosion – I am in the minority, but I think it’s more than a hydrogen explosion.

I actually think it was something called a prompt moderated criticality that was caused by a hydrogen explosion, which then drove the fuel and scattered particles of fuel for as far as two miles from the fuel pool. […]

The important thing though is that it was a detonation. How it was created is less important than the fact that it was a detonation shockwave and no containment can withstand that.

See also: [intlink id=”nrc-be-fission-products-pellets-parking-lot-fukushima-plant-doesnt-make-sense-fuel-rods-be-intact” type=”post”]{{empty}}[/intlink]

Full Q&A session here

Published: March 27th, 2013 at 4:45 pm ET


Related Posts

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  2. Reactor Designer: “It was a nuclear explosion” at Fukushima Unit 3; Plutonium scattered after blast — ABC: “There’s willful denial and lying going on here, even at the highest levels” (AUDIO) November 5, 2013
  3. Gov’t Report: Criticality suspected to have occurred in Fukushima fuel pool — Nuclear chain reaction after massive explosion at Unit 3 compressed fuel together? Concerned about ‘substantial damage’ to fuel (VIDEO) July 4, 2014
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  5. Nuclear Engineer: New cover on Unit 4 can trap hydrogen gas during criticality in fuel pool — Blast would be close to a nuclear explosion, from a practical standpoint (AUDIO) November 22, 2013

28 comments to Symposium Q&A: Explosion at Fukushima Unit 3 drove nuclear fuel out of storage pool — Scattered up to 2 miles away (VIDEO)

  • Urban27

    There should be better information about te third reactor. The explosion was so much greater than the others. Almost all concrete pillars of 6x6ft were broken like pins. this explosion was something quite else. They have been trying to keep the truth about this away from public. But there is no way an open air explosion could make such damage. The containmet vessel is gone. And it was that, that broke because overpreassure. It scattered the fuel that was inside, and can very well also have scattered the spent fuel.
    Twice I have seen pictures of a ten meters thick wall that has been built around it. 30 ft. wall. But it is very rare it is in pictures. This reactor is as exploded as ever chernobyl was!

    • Maxxforce

      The pillars weren't just broken by the blast, the concrete was STRIPPED from the rebar. Look at the early pictures of unit #3. The remains of the upper pillars are hanging next to the building walls by cords of rebar steel. A hydrogen flame front CANNOT ever, under any circumstance, ablate structural concrete from its rebar core. That concrete isn't just "broken", from the refueling floor up to the bottom of the top level, it's GONE.

  • dosdos dosdos

    I still believe it was the layers of molten MOX, the plutonium and uranium layers, in the bottom of the reactor being shaken violently by the hydrogen explosion and forced to mix into a state of super-criticality that caused the detonation.

    • gottagetoffthegrid

      Yep. That's what Arnie said in tech-speak.

      • hbjon hbjon

        Some people have said that it was the smallest possible critical mass. Can a small fusion reaction cause a small fission reaction? Is there enough heat present?

      • harengus_acidophilus


        Arnie don't talk on mixing elements.

        He has figured out the idea of a boiling subcritical spent fuel pool, "moderated" with vapor bubbles. The initial hydrogen explosion has forced the vapor bubbles to collapse and has induced promt supercriticatity.


        • sunpower

          Regarding whether the explosion at unit 3 was in the reactor or SFP, or was caused by a nuclear explosion/supercriticality, Terra Hertz addressed some issues here-

          What does the photo from overhead indicate happened?
          Taking a look at boiloffs in old films of the BWR's in Idaho, and looking at the SL1 event makes steam blowoff plausible to me. Criticality is one rapid heater not the explosive.
          With all the fuel in the SFP or RPV (whichever one says exploded), critical mass would be way beyond that of a Davy Crockett munition, the smallest nuclear device with a lethal blast radius of one third mile. This force of explosion did not occur, killing everyone at the site, because the critical mass was not enriched or 'prodded' with directed implosion. If nuclear explosions can be caused with low NPP enrichment of uranium and plutonium, it would be news to physics so that's why I don't buy into nuclear supercriticality as the explosive at no. 3.
          Steam explosions are powerful enough to do the damage seen as they did in nineteenth century boiler explosion disasters. This topic can be googled in minutes. As for unit 4, SFP4 was reported boiling off early on. I imagine the hottest fuel already melted. They are accomplishing nothing there but more disaster needlessly.

          • omniversling

            Beg to differ sunpower…the MOX proportion in R3 fuel, and possibly SFPs is about the same as early weapons test carried out by the Brits in Australian tests in the 50s and 60s.

            Simialrly fallout was like the Fuku 'Black Dust'. You can see a reference to it here as the black substance rained down on australia during the Maralinga tests. Go to about 13 minutes into the video and listen for about 1 1/2 minutes. You will be shocked. The out of control reactors in Fukushima (U3 at least) are burning cores made up of weapons mixes.

            See also clips on the open BWR tests:

            ‪Safety experiment on a boiling water reactor‬

            ‪Borax [Part 2] – Safety experiment on a boiling water reactor
            ‪Trinity and Beyond The Atomic Bomb Movie 1995 ‬


            • sunpower

              Thanks for your thoughts, Omni. May peace by unto you as well. Here is where I think you are wrong about a supercriticality detonation event at Daiichi-

              Your theory conflates the proportion of elements in a fuel mix with its enrichment level. You did not address the issue of lack of a shaped charge implosion at Daiichi which is present in Oz. The black soot from uranium weapons and an NPP in melt is clearly high temperature aerosolization of material, but black soot can occur without fissioning. For example, burned DU leaves black soot too although U238 has not gone critical. NPPs in meltdown give off metal fumes of Uranium and aerosolation of whatever material the fuel contacts at high temperature.
              The bright fireball of a nuclear detonation was absent at Daiichi, as was a lethal blast radius killing everyone at the site instantly. How could a supercriticality occur without anyone seeing a flash of intense light? No evidence=no confirmation of the hypothesis.
              Addressing your second clip, those BWR experiments which I too mentioned, simply bolster what THertz said about what happened, IMHO.
              I think in the end my conclusion is how out of control is nuclear power production, poorly understood by its operators, and even less so by laypeople. This sick nuclear agenda has been driven from the top down, in secret, and at an incalculable cost to humanity and most complex life forms.

    • Jebus Jebus

      I'm with you to a point dosdos, it all blew up at some point in time. Reactor, containment and SFP…
      And I have to correct one of my posts yesterday, don't know why I had the 17th as the #3 event day. Was it the 15th 0r 16th?
      Anyways, I found this, as an open question…

      • Jebus Jebus

        I look at the next post by HOTR and my first question is answered…

      • pure water

        Jebus, thanks for this video! I really respect Goddards efforts to analyze things, and watched very carefuly. The picture from March 16 does not show some of the girders, because of the black smoke coming out of the hole.It is not water, it is a black smoke, besides the white one! Go, revisit your initial idea. For me it is still the most probable. There are several indications that "black" is coming out of the pools. Watch it again, please.

        • lickerface lickerface

          Exactly what I saw in that video too. I actually thought the narrator was going to say that the reason for not being able to see the girders was because of the heavy opaque smoke! My reality sensor saw one thing while someone else's is trying to convince me my eyes are lying, but I know better. This same "official story vs. my eyes" phenomenon occurred when I analyzed the twin towers and the surrounding structures. It is best to use our eyes first before hearing an explanation. That definitely looks like a smoke screen above the SFP area in that arial if you compare the moving video frames to the still frame which the narrator focused on. Someone else take another look please.

  • Heart of the Rose Heart of the Rose

    Plutonium threat at Japan reactor, expert warns

    The mixed oxide fuel used in the reactor where an explosion occurred today is more toxic than regular uranium, a Japanese nuclear expert warns.

    March 14 2011

    At a press conference in Tokyo, Masashi Goto, who worked for Toshiba as a reactor researcher and designer, said the mixed oxide (MOX) fuel used in unit 3 of the Fukushima Daiichi nuclear plant contains plutonium, which is much more toxic than the fuel used in the other reactors.
    MOX fuel is a mixture of uranium and plutonium reprocessed from spent uranium, and is sometimes involved in the disposal of weapons-grade plutonium.
    Goto added that the MOX also has a lower melting point than the other fuels. The Fukushima facility began using MOX fuel last September, becoming the third plant in Japan to do so.

  • Proton

    Unit #3 explosion was a fizzle… Yes that is a real term… And it will happen with every MOX meltdown from here on out…


  • James Hollen

    I just seen the news on Fukushima here in High Point,NC. Believe me, there is NOTHING in the news about meltdown, radiation in the ocean, nothing! Japan is going to great lengths to cover over this story.

  • unincredulous unincredulous

    lickerface -"Media and journalists control perception, thus "reality". They are the real terrorists."

    Not. We need to get free media and free journalists who act in the good of everyone's interest. This "control" is the terroristic element. "We report and you decide." is the ultimate farce in today's mainstream media. I am very dissappointed in most television news today. The political "discussions" I see are the most annoying to watch. , the ones where three or so personalities pretend to discuss situations. They cut each other off (rude) and it sours people on intelligent analysis of facts. I watched most of one the other day and I remember it as one unpleasant blur of unpleasant personalities. They cut this one woman off every time she spoke, the other three "terrorists" on the show. I have no idea what she was even trying to say.

    And on the radio, there was a discussion about drones in the sky. One guy called in to discuss the downside of the deregulation of drones. He was just siting an example of an instance where someone might be upset with someone and make an explosive device of the drone with gasoline, a firebomb, and kill his ex lover or some other person. And then, just as he began to go into it, a "test of the emergency broadcast system" acted as grafitti on his whole point. I guess that is supposed to be "coincidence"?

    I remember a time when I respected our country (USA) and yes there was media and journalists back then. Still,…

  • dosdos dosdos

    I differ from Arnie in the cause. He is using an old model from the 60's, where a known moderated criticality occurred. His focus is on the spent fuel pool. This is largely based upon the condition of the roof above the SFP.

    I feel that it was a different type of criticality. First off, from what I've seen of the videos of the contents of the SFP, it's far too structured, not enough damage for a criticality to have occurred there. Second, the roof could have been taken off the way it was by a detonation in the reactor by the way the cap came off.

    MOX reactors work in a different way than LEU (uranium) reactors. LEU reactors use precise spacing to create the sustained reaction. MOX reactors use the plutonium as the exciter for the uranium. Spacing of the rods is not so critical to sustain a reaction level sufficient for boiling water.

    When the core melted, you had layers of materials from the core lying atop one another, the heaviest on the bottom, working up to the lightest on top, according to gravity. This would have placed the plutonium layer immediately above the uranium layer. This would have generated a great deal of heat undisturbed. (cont)

    • dosdos dosdos

      Introduce the hydrogen explosion. The layer of plutonium and the layer of uranium would have been hit by the shockwave, and the two molten layers would have mixed together instantly, increasing the level of excitation of the uranium many fold, to the point that it reached a violent criticality.

      This would have made the reactor vessel into a mortar, sending the remaining core contents and the molten mix skyward. This would account for the level of distribution of plutonium and uranium across the general area for miles around the plant much better than that of the SFP, which is still relatively intact (considering the collapse of building mass into the SFP).

      I agree with Arnie that it was a nuclear detonation. I just feel that it was a MOX event in the reactor, not a moderated criticality in the SFP. Arnie's explanation is an argument for not leaving SFP's overloaded as they are now. My explanation allows for Arnie's warning, since it's been already been proven decades ago, but my conclusion is that MOX is a very dangerous fuel in a meltdown. MOX should be banned, period.

  • Mad Scientists Mad Scientists

    When you compare these photos, Unit 3 certainly looks like a detonation:

    Photo of an atomic blast during atomic testing in Nevada

    Compare it with Unit 3 explosion:!/img/httpImage/alg-nuke-reactor-explosion-jpg.jpg

    Maybe the nuclear industry doesn't want to admit that this can happen.


    1. Millions of people live around nuclear power plants. IF they can detonate, that's a huge problem for the nuclear industry.

    2. The MOX industry must be a trillion dollar business by now.

    (a) $8 billion dollars for the MOX plant in South Carolina, where AREVA is making a bundle

    (b) 30 reactors in "Europe (Belgium, Switzerland, Germany and France) are using MOX and an additional 20 have been licensed to do so."

    3. MOX fuel was supposed to be their great hope. "Turn swords into ploughshares" they said of Mox fuel.

    MOX being dangerous doesn't fit into their plans.