NHK: “This is a very severe accident” — Nuclear fuel at Reactor No. 1 may have melted through 65 cm of concrete… Only 37 cm at thinnest point (PHOTOS)

Published: November 30th, 2011 at 3:12 pm ET
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“Now They Tell Us” Series: TEPCO Admits Reactor 1 Corium May Be 65 Centimeters into the Concrete Pedestal of Containment Vessel, EX-SKF, Nov. 30, 2011 (Emphasis Added):

From NHK News (11/30/2011; quick translation, subject to revision)

[...] In Reactors 1 thorugh 3 of Fukushima I Nuclear Power Plant, core meltdowns have occurred, and it is considered that part of the melted fuel has dropped from the RPVs to the CVs. However, the details are not yet known even after more than 8 months since the accident started.

Using different methods, TEPCO and various other research institutions have been analyzing the state of the melted fuel based on the reactor temperatures and the amount of water being poured into the reactors, and the results were announced on November 30 at a workshop held by the national government.

TEPCO’s result shows that, in the most severe case, all of the fuel would have melted, of which a significant portion pierced through the bottom of the Reactor Pressure Vessel and dropped onto the Containment Vessel. [...]

When the melted fuel drops to the bottom of the Containment Vessel, a core-concrete reaction takes place at a high temperature, melting the concrete. [...]

In the worst case, in Reactor No. 1:

  • Melted fuel could reach 65 cm deep into concrete
  • At the thinnest part of the concrete, it is only 37 centimeters to the outer steel plate of the containment vessel
  • This is a very severe accident

In the worst case for Reactor No. 2:

  • 57% of the fuel has melted and part of the fuel dropped onto the containment vessels (See above statement by NHK: “TEPCO’s result shows that, in the most severe case, all of the fuel would have melted”)

In the worst case for Reactor No. 3:

  • 63% of the fuel has melted and part of the fuel dropped onto the containment vessels (See above statement by NHK: “TEPCO’s result shows that, in the most severe case, all of the fuel would have melted”)

“I don’t think it is wrong, but it is only the first step. You can’t get answers from only one analysis. We will need to understand the situation from various analyses.” -Seiji Abe, technical advisor to the Japan Nuclear Energy Safety Organization (JNES)

See EX_SKF’s report for links to 6 .pdf’s in Japanese

Published: November 30th, 2011 at 3:12 pm ET
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Related Posts

  1. *NEW Dec. 1 Yomiuri* Gov’t Study: Reactor pressure vessel may be “tilted” after corium melted through concrete floor up to 200 cm deep November 30, 2011
  2. Tepco: 68 tons of nuclear fuel melted at Fukushima Reactor No. 1 December 1, 2011
  3. Report: If fuel melted through reactor, it would react with concrete floor of primary containment — Could add significantly to total radiation release May 23, 2011
  4. Gov’t: Fuel melted “much deeper” into concrete at Fukushima reactor than revealed — Triple the depth of original estimate — Tepco: “Impossible for us to evaluate potential impact” August 8, 2014
  5. NHK: Over half of fuel has melted out at Reactors No. 2 and 3, says Tepco’s assumed worst scenario (VIDEO) November 30, 2011

19 comments to NHK: “This is a very severe accident” — Nuclear fuel at Reactor No. 1 may have melted through 65 cm of concrete… Only 37 cm at thinnest point (PHOTOS)

  • James Tekton James Tekton

    Ah great,

    Questions answered and how now long it takes to hit the water able?

    Time tells.


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    • arclight arclight

      more questions that answers for thick old me! :)
      how long it will take to burn through the 7.6 meters of concrete?
      and is the strata diagram the beginning of whats under the concrete?
      be nice to now what the diagram of the layers of strata means..

      and what rocks are there? also how permeable the rock stratas are?

      do we believe this data?


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  • radegan

    These past few days are laden with huge admissions by the Japanese government and TEPCO. It does seem that something has changed. I think they’re asking for help but part of the world has war plans and don’t want to set them aside. So the Japanese are willing to share more details, as many details as it takes to get the warriors to see their own children are already in danger from an unseen enemy and the radiation readings and effects they are hiding will soon crimp whatever war plans they have anyway.


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  • Really the same pattern of Tepco admitting facts months after we have been talking about it here. But how can they contemplate removing the fuel when we read recently they can’t even service temperature gauges because the radiation is so high?

    Such a mess.


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  • Mauibrad Mauibrad

    If the corium are in the cement, then they cannot be effectively cooled.


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  • lam335 lam335

    Didn’t a scientist this summer speculate that the fuel could already have burned several meters into the earth below the containment? What makes them so sure its still just making its way through the cement foundation? Would that produce steam?


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    • stopnp stopnp

      Everything that has been stated so far by the japanese government and tepco has been a guesstimate. They don’t even know where the corium are. Considering the fact that they can’t even get close enough to the reactors to read a damn temperature gauge, I find it hard to believe anything that they have tto sy


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      • stopnp stopnp

        My opinion is that the core melted through months ago. Since we’re still seeing steam I would have to deduce from layman’s logic that the corium are still reacting. There were reports of workers seeing steam coming through cracks in the ground a couple of months ago.


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  • CB CB

    Something comming up out of the vents at unit 1 now.


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  • farawayfan farawayfan

    57% 63% 65cm? from random spot temp measurements in areas where there isn’t any core anymore? /goggle I predict a 12.2345345% chance that it’s those numbers and a 99.99999999999% chance they don’t have a damn clue. garbage in, garbage out, exacerbated by garbage work. My apologies to garbagemen, you do far more honest work than these scum.


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  • Grampybone Grampybone

    Based on previous TEPCO reports the certainty that the statistics they release are accurate is low. With the two choices of 63% or “The whole core” chances are that every last drop of it is eating concrete. The fact that the utility has presented data like this so late into the year after the core is estimated to be at 63cm into the ground shows how little they really knew. The distance traveled over 8 months needs to be calculated. The amount of time to burn through 6 meters of ground must be estimated. Vital timetables can be made with the data above and the known facts here at Enenews. I hope we can see how much time we have left before “unknown” fission events start when raw core reaches ground material. If it took 8 months to reach 64cm than every 16 months estimated travel would be 1 meter 28cm. Looks like we have at least 2 years before the core is on ground water.


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  • stock stock@hawaii.rr.com

    Great Source of Info on Energy to melt concrete

    Also keep in mind that steel melts around 2500 deg F, Corium fissions at around 5000 deg F “Blob temperature”. The cute little “blob” that TEPCO showed in their recent drawing of a Corium out of the box was deceptive in size, the real mass of the Corium will be !!!! 200 TONS !!!! of fissioning, poisonous, super hot hell on earth. Y’all TEPCO boyz got a 200 ton blob of stuff and you can’t tell me where it is?

    http://oahutrading.blogspot.com/p/japan-nuclear-information.html


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  • Anthony Anthony

    New radiation treatment lets workers survive ‘fatal dose’ – even AFTER they’ve been exposed
    By DAMIEN GAYLE
    Last updated at 7:52 PM on 30th November 20
    http://www.dailymail.co.uk/sciencetech/article-2068215/New-breakthrough-double-drug-radiation-treatment-help-workers-poisoned-Fukushima-nuclear-disasters.html


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    • Hemisfear311 Hemisfear311

      According to the article, the new treatment has only been tested on mice and it doesn’t say how much the treatment actually helped. Why not turn the Fukushima workers into guinnea pigs, and test new drugs on them? If they don’t make it who can blame the drugs afterwards? Would the pharmaceutical companies pay Tepco for such a chance to test their drugs? We will probably never know.


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  • evendine

    Here’s a paper on simulated corium erosion of concrete (using thermite in place of corium) The thermite reaction is much cooler than corium (around 2000 degC instead of 5000 degC, but it still erodes the concrete at 4cm per minute!

    Typically for Tepco, the figures they’ve given are almost certainly rubbish. According to this study, 7.6m of concrete would last just over 3 hours!

    http://bibliothek.fzk.de/zb/berichte/FZKA6453.pdf


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  • evendine

    Why don’t they use seismic imaging of the foundations / underlying strata to gather some data on what’s actually happening!?


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    • aldo aldo

      I’ve been wondering the same evendine, if you find anything please post here, thanks. Seems odd they lack any technology to remotely sense the location of a corium of all things. Seems like the radiation it emits is doing 99% of the work.


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