‘Significant failure of containment’ inferred by NRC after first explosion — Protective actions ‘well beyond 50 miles’ if containment failure

Published: February 27th, 2012 at 9:55 am ET


Follow-up to: [intlink id=”nrc-suspected-detonation-at-reactor-no-1-weeks-before-gundersen-postulated-such-a-scenario-at-no-3″ type=”post”]{{empty}}[/intlink]

Title: Japan’s Fukushima Daiichi ET Audio File
Source: Nuclear Regulatory Commission
Date: March 12, 2011

Page 55

CHAIRMAN JACZKO: […] We have video footage that we believed showed containment has been violated.

MR. DORMAN: Yes, what is it, is — I’ll try to describe it for you. From a distance, you’ve got the plants in the center. You’ve got four reactor buildings and behind them, from the point of view of the camera, is the turbine building and then the sea, and what you see is, on the left-most, which would be the Unit 1, from the vicinity of the reactor building, you see an initial vertical pulse —


MR. DORMAN: — and then a large white cloud, spread out from that reactor building, and then you have footage of a later image, where you have the three reactor buildings to the right are solid white images, and the one where the — you know, the explosion occurred, appears to be the metal frames of the portion of the building above the refueling plug and the spent fuel pool.


MR. DORMAN: And based on that, our assessment is, it appears to have been an event that originated in the reactor building.


MR. DORMAN: And our assessment is that there is possibility that that would — and event like that involved a failure of the primary containment.



MR. DORMAN: But again, that’s all our inference off some media footage.

Page 81

CHAIRMAN JACZKO: Can you just summarize again for me, what your thoughts are on that?

MR. DORMAN: Yes, our inference from the explosion that we’ve observed is that the explosion was in the reactor building and represents a significant failure of the containment, primary containment function.

Page 83

MR. DORMAN: Okay, yes, we did — the PMC did look at a scenario involving 100 percent core damage, along with the containment failure, which as you can imagine, would be a significant event with protective action guidelines well beyond 50 miles. But again, at this point, we do not have an indication that there is anything like that kind of core damage, but that would be kind of a bounding scenario.

Published: February 27th, 2012 at 9:55 am ET


Related Posts

  1. NRC officials suspected a ‘detonation’ at Reactor No. 1 weeks before Gundersen postulated that scenario at No. 3 February 27, 2012
  2. US Dept. of Energy memo indicates ‘after-shock’ resulted in explosion at Reactor No. 1: NRC Chairman February 27, 2012
  3. Gundersen: Top lifted off Reactor No. 1 containment BEFORE explosion? (VIDEO) February 9, 2012
  4. Gov’t Nuke Experts: Top part of Reactor 1 containment may have opened up before first Fukushima explosion October 17, 2012
  5. Japan Nuclear Expert: “Containment vessel continued to break at various spots, one after another” from Fukushima melted fuel — “It lost the protective wall which seals in radiation” (VIDEO) March 13, 2013

5 comments to ‘Significant failure of containment’ inferred by NRC after first explosion — Protective actions ‘well beyond 50 miles’ if containment failure

  • sschu

    Just wondering:

    If R1 explosion was failure of primary containment, what was R3 explosion?

    Is this why they put a tent over R1?

    If so, then neither R1 & R3 have any method to contain the reaction.

    Why isn't Tokyo evacuated?

    Why isn't someone in jail?


    • James2

      I wonder the same thing.

      I have always thought it plausible that the #1 explosion was primarily hydrogen that collected at the top of the reactor room and blew the walls and roof out.

      I think the sequence is this; earthquake causes automatic scram of the reactor – which may or may not have happened correctly. After the tsunami all cooling was lost, so the reactor core melted down quickly and created hydrogen, It also probably breeched the bottom of the RPV very quickly.

      At that time there was a lot of hydrogen and it floated to the top of the building, where it ignited and blew off the structure. In this case, the containment breech was probably in a way that allowed the pressure to blow off.

      On #3 you had the same thing, but the containment was probably stronger, and the top of the containment blew and some or all of the reactor itself blew out the top of the primary containment like a bullet out of a gun.

      Both of them are primary containment failures, I guess.

  • sschu

    I have been reading this stuff for a year and still am not sure about the difference between the reactor pressure vessel and primary containment structure. They are different, correct?

  • James2

    yes, I can answer that one. The RPV is a steel structure that houses the rods themselves and where the reaction happens.

    It's cigar shaped, about 50 feet long and placed into the building vertically. The top end of it has a removable cap so they can load and unload fuel.

    The walls are something like 5 inches thick and it can withstand tremendous pressure and temps.

    The primary containment is a thick layer of steel and concrete that surrounds the RPV. It is bulb shaped at the bottom and cylindrical at the top. It also has a steel cap that is bolted down over the RPV lid and above that a concrete "plug" that comes up to the "reactor floor" level.

    The primary containment's job is to contain the fuel in case of RPV failure or meltdown. It obviously doesn't work.

    you'll also hear about the "secondary containment – which as far as I can tell is the building surrounding the whole thing. On unit 1 this was pretty much a "barn" type metal siding above the reactor floor – but on 3 and 4 (I think 2 is similar to #1) the walls and roof are much sturdier concrete/steel.

  • Kevin Kevin

    Busby states that he did testing throughout Japan and in Tokyo.

    He claims, and this is fascinating, that the DOE(US), had been doing testing from the beginning in Japan. He goes on to point out that the US embassy in Tokyo had high volume air testing equipment used on their roof there. He says he was leaked a document from the DOE, and he believes that he was the only one to receive this leak. The information in the leaked document outlines this and extremely high radiation reaching the US Embassy in Tokyo similar to the findings he found in car air filters in Tokyo. He does not state what the readings actually were.

    You can find this at this blog.


    Go to February 03 2012 an interview with Moret and Busby. It is at about 3/4 the way through the podcast. I cannot say exactly the minute as the player of mine does give that detail.

    Busby states that although these findings were found right in Tokyo on top of the US embassy roof, they were never disclosed.