Gundersen: Damage to Fukushima Unit 3 fuel racks could be from prompt moderated criticality, not objects falling in pool — What does Tepco know that they haven’t yet shown photos of?

Published: December 21st, 2012 at 5:01 pm ET
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Regarding Tepco’s recent statement that the fuel assemblies in the Unit 3 pool could have been damaged by shock when the steel beams or 30-ton fuel exchanger fell, Fairewind’s chief engineer Arnie Gundersen writes in to ENENews:

Another possible reason for damaged U3 racks could be a prompt, moderated criticality. What does TEPCO know about the U3 racks that they have not yet shown photos of? The photos I have seen are very murky, very blurry. I wonder if TEPCO has better quality pictures?

See also: Nuclear expert: Powerful explosion at reactor No. 3 may have been from "prompt criticality" in spent fuel pool (VIDEO)

Published: December 21st, 2012 at 5:01 pm ET
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Related Posts

  1. Asahi: New photos show extensive damage at No. 3 fuel pool — 35-ton machine that appears to be on fuel racks is a crane April 14, 2012
  2. New images of Unit 3 fuel pool show debris near surface, possibly in danger of falling inside — Tepco investigating “condition of steel members partially immersed in pool” (PHOTOS) September 13, 2012
  3. Kyodo: Steel beam removed from Fukushima plant’s No. 3 pool after falling on fuel racks — Another steel beam found soon after (PHOTOS) December 20, 2012
  4. Gundersen: White haze in photo of Unit 3 is coming from spent fuel pool — Almost as dangerous as Unit 4 (PHOTOS) July 12, 2012
  5. Tepco: Fuel assemblies could be damaged from shock in Fukushima Unit 3 pool December 21, 2012

14 comments to Gundersen: Damage to Fukushima Unit 3 fuel racks could be from prompt moderated criticality, not objects falling in pool — What does Tepco know that they haven’t yet shown photos of?

  • HoTaters HoTaters

    Gundersen: Damage to Fukushima Unit 3 fuel racks could be from prompt moderated criticality, not objects falling in pool — What does Tepco know that they haven’t yet shown photos of?

    "What does Tepco know that they haven't yet shown photos of?"

    Thank you, Mr. Gunderson. I've been asking myself the same question for a long, long time.


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  • moonshellblue moonshellblue

    I wonder if the corium also turned into dust like TMI. 36%m or more of the remaining melted fuel at TMI was dust thus perhaps that is why the Muons were unable to detect anything. Does anyone know? Thanks in advance


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  • JoeNeubarth

    I am still convinced that the immediate secondary explosion in Unit Three was from the basement and that it was a steam explosion as I postulated over a year and a half ago. It was vectored upward as if it came out of a shotgun barrel. To get an effect like that, it had to come from the depths of the building.


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    • voltscommissar

      "THE DEVIL'S EJACULATE"

      +1 to JN's posting, but I would add that when the "steam" is black then it ain't just steam.

      As I've posted at enenews before, there is an excellent book "Tritium on Ice" by nuclear physicist Kenneth D Bergeron (MIT Press, 2002) in which he describes the horrors of a steam explosion more accurately (or maybe it's just a subset of all possible steam explosions) called Direct Containment Heating or DCH, where for a GE Mk1 the molten fuel eats thru the bottom of the RPV, squirts downwards as a very high pressure jet, mixes with and boils oodles of water in the suppression torus and creates such a massive pressure build-up that the containment blows within milliseconds of the RPV failure. It is the near simultaneous failure of RPV and containment that I believe we witnessed with that black 'vectored' upthrusting ejection of nuclear crud from unit 3.

      The Devil's ejaculate. Thanks for nothing, General Electric.

      The bright flash from the SE corner of Unit 3 building is a separate event, though probably triggered by the DCH event. I'll post my YouTube enhanced video of that in (serious) reply to the other question on prompt moderated criticality.

      If Arnie disagrees with this, I wish he would say so. I cannot get him or Maggie to respond on Bergeron's DCH ideas…


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  • Heart of the Rose Heart of the Rose

    "prompt moderated criticality"?…failure?
    Why would a 'prompt moderated criticality' be used in this instance?.
    Ya..I'll learn.
    What is a 'prompt moderated criticality?


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    • AGreenRoad AGreenRoad

      The explosion was 'prompt'; meaning it was 'on time' and under budget, plus fast. No one objected to it. Very prompt indeed.

      moderated; meaning covered up, denied and called everything but what it was. Mass media does not cover it, so it NEVER HAPPENED. If it is talked about, it is called a 'steam' or 'hydrogen' explosion, rather than what it really was.

      Criticality; meaning no mass media is critical of what happened at Fukushima. No one was was held accountable for the largest nuclear disaster in history. That is what is called a 'criticality'…


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    • voltscommissar

      A prompt moderated criticality is a dirty nuclear bomb, where the energy yield is very very small relative to the amount of fissile material nearby. The pressures and the geometry are just not right for enough neutrons to chain react with enough U235 to flatten everything within a 5km radius.

      So all we got was a bright flash from the SE corner of the Unit 3 building, almost before the walls had blown out from the force of the steam explosion.

      The bright flash appears to RETREAT backwards into the exploding building, against the direction of the expanding steam blast. This "magic" or paradox is best explained IMO by the flash being merely intensely hot ionized air molecules from a gamma/X-ray burst from the prompt criticality itself.

      So if there was a gamma/X-ray burst, then the US military and all the CTBTO satellite sensors would have detected it instantly. Still no word from the Pentagon on that one….. we are all waiting patiently for public disclosure (but don't hold your breath!)

      Arnie, please critique this theory, when you've got time….!

      and here is my enhanced video http://www.youtube.com/watch?v=Wc4KZoevt10


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    • Fury Fury

      a prompt moderated criticality does not happen outside of a nuclear raector core, can't. It assumes that the "prompt" neutrons, or the "fast " neutrons that are produced in very small quantitys usually are going to set off a chain reaction, a short term "millisecond" reaction. outside of a reactor core you would have to pile up a block of uranium close to a yard on a side, or pure plutonium 4" or more in diameter. Or compress the HELL out of it first.! TONS of pressure!!


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  • AGreenRoad AGreenRoad

    The rats did it..

    The explosion at #3 was ONLY methane gas from the rats passing gas, nothing more.


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  • PhilipUpNorth PhilipUpNorth

    VERY CUTE, you guys. Does anyone have a serious comment OT?


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