NRC’s possible worst case scenario: Examined MOX at No. 3 — Also speculated steam explosion would “reject an entire core” from reactor

Published: March 6th, 2012 at 11:34 am ET


Japan’s Fukushima Daiichi ET Audio File
Nuclear Regulatory Commission
Friday, March 18, 2011

CHAIRMAN JACZKO: So I think we really should produce a source term that is truly what I would call a worst-case but a possible scenario.


CHAIRMAN JACZKO: I don’t know if that’s feasible. If folks can think of what, you know, if there’s any physical limitations. I mean, obviously, if you melt the core, you’re not going to volatilize everything in the core, can you?

BRUCE ROPER: I don’t know the answer to that. We can always talk can only talk about plate-out and things like that, so it all doesn’t get out.


BRUCE BOGER: It sticks to the sides of the walls.

CHAIRMAN JACZKO: Yeah. And it’s not all — I mean, some of it is solid still.


CHAIRMAN JACZKO: And I guess it’s the iodine and the cesiums that you worry about. It’s not the uraniums and the, you know, the hotter, the heavier elements; right?

TRISH HOLAHAN: Yes. And we’ve also been asked to look at the MOX capability, you know, the MOX fuel in Reactor 3.

CHAIRMAN JACZKO: Yeah, in the pool?

TRISH HOLAHAN: Yeah. We, we thought that that was wasn’t significantly contributing to the dose.

CHAIRMAN JACZKO: Ah, okay. Okay. Interesting. Okay. Well, yeah, okay. Well, then maybe that’s the driver. Maybe it doesn’t matter then what we do with the other things because it won’t really act appreciably much anyway. Just go back one more time and, and look and see if you can’t come up with a, with what I would call a true worst-case scenario; namely, the worst-case that is physically possible.


CHAIRMAN JACZKO: See if you can do that because I, I have to believe that there is no possibility in a light-water reactor design to reject an entire core. I mean, that’s basically steam explosion; isn’t it?


CHAIRMAN JACZKO: And, and I think we’ve ruled that, as an agency, we’ve ruled that out as a physical possibility.

TRISH HOLAHAN: Okay. I can —

CHAIRMAN JACZKO: See if you can just take another run at that and give me a ring back and see what that looks like.

TRISH HOLAHAN: Okay, I’ll talk to the Reactor Safety Team.

CHAIRMAN JACZKO: Okay. All right.

More on the ‘impossible’ steam explosion: [intlink id=”us-govt-experts-think-melted-fuel-rods-landed-in-water-under-reactor-no-2-causing-steam-explosion-pressure-dropped-dramatically-at-same-time-clear-indication-primary-containment-lost” type=”post”]{{empty}}[/intlink]

Published: March 6th, 2012 at 11:34 am ET


Related Posts

  1. Fukushima Plant Chief after 3/11: “Reactor 3, probably steam explosion, it just happened!” — NRC Chairman had said a steam explosion could “reject an entire core” (VIDEO) August 9, 2012
  2. Goddard’s Journal analysis indicates steam explosion at Reactor No. 3 — NRC discussed steam explosion ejecting entire core (VIDEOS) April 10, 2012
  3. Japanese Diplomat: It is speculated that melt-throughs at Reactors 1-3 might lead to ‘unintended criticality’ or steam explosion June 14, 2012
  4. Asahi: The explosion at Fukushima Reactor 3 had seriously damaged Reactor 2 — “Worst possible case” was predicted soon after — Many workers abandoned facility March 21, 2013
  5. Fukushima Boss after 3/11: “It’s awful, awful… No. 3 reactor just blew, probably a steam explosion” — Steam explosion, not hydrogen? Reactor blew up, not reactor building? (VIDEO) October 13, 2012

49 comments to NRC’s possible worst case scenario: Examined MOX at No. 3 — Also speculated steam explosion would “reject an entire core” from reactor


    We should all know by now, there's only a few days left before the first year anniversary of the Fukushima catastrophe. We must not leave it to the MSM to define this incident. We need to define this event! So, let's start thinking of how you’d like to see this event being memorialized by future generations, as well as our own. This is the just the beginning of what will be decades of hard truth, coming-down upon us all. We are the vanguard of this truth and must hold-fast to its power. We have only a few days left. Let's try to think-up and do something that lights-up the internet with a million candles and prayers. Within the next twenty-four hours, we should have everyone's input on this.

    I was thinking that everyone should light four candles to mark this sad occasion. The four candles would be symbolic of the four reactors. Amongst other aspects, they can be representative of ideas/concepts that we can all agree too; such as love, peace, truth and life. They can also represent the four directions of the world that will be devastated by this catastrophe. This idea of four elements is fundamental to the transfer of esoteric knowledge and is easily grasped by all.

    This memorial effort can go a long way towards seeing the light, with all of your input and support. Announcements that everyone will be doing this should also be made on other sites, as well.

    Detectors-a-tick’n! We need to move fast on this…

    • Whoopie Whoopie

      Got one. 🙁


        That's amazing! Truly beautiful! Curious if anyone would want to setup a memorial webcam?

      • NoNukes NoNukes

        We would need more than 4 candles, that would give a minimizing impression. They have admitted that 5 and 6 melted, too, not even to move beyond F1, which we probably should..


          @NoNukes: so exactly how many of these plants are in actual meltdown? I thought it was three, with the fourth disabled…

          • NoNukes NoNukes

            March 6, 2012 at 1:13 pm · Reply
            From article linked above:

            CHUCK CASTO: And we certainly know, I think we absolutely know that pool No. 4, though, the walls have collapsed ….
            BRUCE: — you indicated that the walls of the pool were damaged or down?
            CHUCK CASTO: Yes."

            NoNukes: So, since "we absolutely know that pool No. 4, though, the walls have collapsed …." there goes #4, and the transcripts posted in the past few days noted that 5 and 6 had "partial meltdowns," too, which we can understand to mean that the corium is about to the groundwater by now.

            I am not sure of the number "offline" NPPs in Japan total, but there were reports of at least 11-42 down in various places. 3 candles is not enough, and an accurate number may be a fire hazard.

        • NoNukes NoNukes

          More importantly, the NRC suggests above that the R4 SFP is GONE! So, Arnie's song and dance about how if it fell then "Japan would have to evacuate" was probably "limited hangout" of the worst kind.

    • BreadAndButter BreadAndButter

      Hi Aftershock, wonderful idea.
      I suggest we not only light the internet, but also our windows!
      I printed a simple "Japanese flag" banderole on paper and wrapped it around an empty glass – and put the candle inside.

      I will also take it to the chain of lights organised in our town on Sunday.


        @BreadAndButter: I agree! I will be placing the appropriate amount in my kitchen windows for the world to see. 'jec' brought up the issue as to other disabled plants. I explained that the amount of candles should only reflect the actual amount of NPPs that are in meltdown. Is it three or four? If it's three, then we may want to change the count. Remember, this is going to be the start of an annual memorial ritual. We should get it right…

        • HoTaters HoTaters

          Diani #2 as well? Clearly problems there too but unclear if it melted down.


            @HoTaters: couple of things: we need to establish how many plants are in actual meltdown. I'm not sure so I'll leave it to others to tell us. Unrelated, but next on the list is that I left you an email response this morning. Nothing too important, but thought you should know. Finally, I'll be jumping out of here for a bit to tend to other issues. Keep the home fires burning (forgive the sick attempt at humor)…

    • karaa karaa

      I will do this and I thank you for idea. In france, we have a (I hope) very big manifestation, a human chain on the road near the power plants

      <a href="; title="Le 11 mars 2012, réagissons ensemble pour sortir du nucléaire !"><img src="; border="0" width="400" height="70"></a>

  • Bobby1

    "TRISH HOLAHAN: Yes. And we've also been asked to look at the MOX capability, you know, the MOX fuel in Reactor 3.

    CHAIRMAN JACZKO: Yeah, in the pool?


    There was MOX in the #3 SFP?

  • HoTaters HoTaters

    From NRC discussion on March 16, 2011, NRC discussing walls and structure of Unit 4 completely gone, spent fuel pool dry. Discussion says because NRC had reported SPF only dry (and not lacking walls, etc) they might go with what had already been reported (just dry), to be consistent.
    The headline:

    NRC Transcript – TEPCO relayed information Unit 4 SFP Dry – Walls collapsed and incapable of holding inventory – Unit 3 “everything else gone” –
    Posted by Enformable on March 5, 2012 in BWR, FOIA, Fukushima Disaster, March 2011, NRC, Top Docs – FOIA · 1 Comments

    The more I read from the NRC transcripts, the more upsetting it gets … CYA, we can't change our story even if it's bad and it's the truth, because we've got to be consistent!


    • HoTaters HoTaters

      From article linked above:

      CHUCK CASTO: And we certainly know, I think we absolutely know that pool No. 4, though, the walls have collapsed ….
      BRUCE: — you indicated that the walls of the pool were damaged or down?
      CHUCK CASTO: Yes.
      NRC CHAIRMAN JACZKO: I’m not going to get into that level of detail. I mean the relevant factor is it’s dry.
      CHUCK CASTO: Yes, and they can’t maintain inventory at all.
      MALE PARTICIPANT: Chuck, we got a briefing before from Tony and John, and they indicated that there was structural integrity to the core pool.
      CHUCK CASTO: When was that?
      MALE PARTICIPANT: That was about four hours ago.
      CHUCK CASTO: Well, then, I need to tell the Chairman that because that’s not what we understood just a few hours ago.
      MALE PARTICIPANT: But it’s okay because he’s not going to get into that level of detail. But we just need to be careful about consistency in the assessment of the information. I know it’s going to change, too.
      CHUCK CASTO: Yes, well, we were consistent. That’s what we heard; that’s the last we were told, that the walls were not there.
      MALE PARTICIPANT: Right. Because our discussion with part of your team was we thought you had abandoned the notion of putting coolant back in that pool and that you were looking more at dropping sand or something else like that?
      CHUCK CASTO: No, we didn’t suggest that at all yesterday. The Reactor Safety Team suggested the sand. We were still working with water on all four pools.
      And, then, I said let’s go both ways.
      BILL RUAN: Yes, because there’s no fuel pool left.
      CHUCK CASTO: Right.
      BILL RUAN: Unit 3, he believes
      And basically, everything else is gone, and at least in his opinion, and, of course,
      Chuck knows this, Jim’s opinion is there’s no water in the pool.
      BILL RUAN: Unit 3.
      Unit 2, he believes it’s drying out….
      BILL RUAN: They’re drying it out.
      And, then, the only pool that might be okay is Unit 1.

      Also discussed problems with…

      • HoTaters HoTaters

        Did you get this?

        CHUCK CASTO: No, we didn’t suggest that at all yesterday. The Reactor Safety Team suggested the sand. We were still working with water on all four pools.
        And, then, I said let’s go both ways.
        BILL RUAN: Yes, because there’s no fuel pool left.
        CHUCK CASTO: Right.
        BILL RUAN: Unit 3, he believes

        UNIT 3, HE BELIEVES.

    • HoTaters HoTaters

      Am not sure WHAT they were trying to be consistent with, whether it was updating the report the walls were gone on SPF 4, or whether they were sticking with the earlier report SPF 4 was only dry.

      The telling part of this is they agreed all the SPF's were compromised except #1.

      So what happened to all the SPF's ????

      That's what I want to know!

      • HoTaters HoTaters

        Just one last comment. What the NRC person said about venting reactor #2 at Daini is consistent with the NKK (?) reporter's coverage, in the video where he is flying over the plant, and starts talking about Daini. IMHO he was talking about the hole in the side of the building at Daini #2. So it appears they combined video from both sites, and it would give English speakers the impression there were only problems at one plant (Daichi).

    • Bobby1

      Maybe I missed something. The initial report was that the #3 reactor had only recently been fuelled with MOX, and the rods in the SFP was from the old conventional fuel.

      So now those SFP #3 rods all over the place are spent MOX rods?

      • StillJill StillJill

        Yes Bobby1, that is my understanding. Mox, plutonium, etc,…Uranium too right? All over the area and mountains,…somewhere between 1-5 miles, (ish)

      • PhilipUpNorth philipupnorth

        It has become clear that the refueling of #3 was well under way, or had been completed, and that the reactor had been capped, prior to the earthquake of 3/11. (This is contrary to the TEPCO story.) The reactor had to have been capped for it to go boom, as it did. The SFP at #3 was destroyed when the reactor in #3 blew the building up, scattering it's contents all over the area, as has been documented. The reactor #3 went boom, taking the contents of the #3 SFP up with it. The plume that passed over Tokyo a day or two later, contained the MOX fuel from reactor #3 (not from SFP.) People in Tokyo are already dying as a direct result of TEPCO's lie that new MOX fuel was still in the SFP and not in the reactor. Check me out on this, ENENEWS. This is where we are at in understanding what happened at #3, right?

        • Bobby1

          I guess I did miss this. So spent MOX rods were scattered up to 13 miles away (according to the transcripts).

          • PhilipUpNorth philipupnorth

            So the entire MOX core of #3 reactor was ejected, per the NRC discussion.

          • PhilipUpNorth philipupnorth

            Making what happened at the #3 reactor the worst case scenerio, according to the NRC, right?

          • Cataclysmic Cataclysmic

            Seems like I remember reports of this initially, or soon thereafter that were obviously shoved under the carpet.. It is really weird to relive what many here lived through a year ago. or so… nothing here is new news.. we knew, we warned, we squawked, we cried, we yelled and screamed, and everybody, our friends and families labeled us crazy conspiracy theorists… now, the evidence and documentation are out.. and what we railed against is in fact worse than what even most of us "crazys" were all crazy about..

            • moonshellblue moonshellblue

              Thanks for typing out what I have been thinking.

            • That's standard operating procedure. It took 'em two years to admit melting at TMI, and they still haven't admitted that half the core inventory of volatile fission products got released from the fuel. When Fukushima melted a year ago next week, pro-nuclear apologists dismissed me rudely when I asked how much hydrogen was being vented. As in, "melting nukes don't generate hydrogen!" The next day, when the whole world knew melting nukes generate hydrogen (and explode), it was suddenly "everybody knows melting nukes generate hydrogen and explode."

              It took weeks and months for details about Fukushima got released publicly by TEPCO and/or the Japanese government. People were bitching about Jaczko's 50-mile evacuation recommendation for months. Phone calls on March 12 per these transcripts had Bill Borchardt and the rest of the technical management at NRC saying after unit-1 exploded that they needed twice that. Japan didn't go 20 miles and STILL hasn't extended the dead zone to where it needs to be along plume paths. There's a time-delay setting on every little detail. We may hear about it in the media (like here at enenews), but it could take months for 'official' confirmation so the mainstream news reports it. Always as if it's something new, which it hardly ever is for those paying attention.

              That said, this is "worst case" speculation, using unit-1's explosion as a model, but with blown primary containment (they bought NISA's story that primary was still intact at unit-1). It took a couple of months before TEPCO/gov admitted there was primary breach at unit-1. More than 5 months for unit-3. Unit-2's torus blow-out was reported during the first week. As a way of accounting for accumulating coolant water all over the place and going into the sea. There were 'rumors' and reports all along, just no 'official' confirmation.

              These transcripts are OUR 'officials'. Their speculations early on aren't necessarily factual. They're…

              • aigeezer aigeezer

                JoyB – it got cut off. I hope you'll continue the thought.

                • Just pointing out they were 'gaming' scenarios – Exelon was running simulations for GE (which had 70 engineers on the ground in Fuku/Ibaraki working outages when the quake happened) to time meltdowns, melt-throughs, hydrogen generation, steam explosions from the primary, how much core inventory might get released, where it might go, pre-placing assets and organizing with FEMA, DHS, State, FDA…

                  They were getting most of their updates from CNN and FoxNews, just like everybody else. They had the entire nuclear industry via NEI, ANS, INPO, WANO, etc. running projections and doing the math, but they got their news from the television too. TEPCO and the Japanese government (all nuclear related branches) weren't talking, didn't want any 'help', and real data was rare.

                  Just cautioning that you can't actually consider the early speculations – and this is specifically labeled speculation – as some kind of 'truth' about what happened at Fukushima.

      • James2

        The MOX was placed into reactor 3 in August 2010.

        Tepco records say there was no MOX in SFP3. If MOX is on the ground (it was/is) then it came from the core – just another round of proof that the core of #3 blew on March 14th.

        They have been denying this from the beginning. They know full well that the plutonium left the reactor, and that MOX was proven unsafe at Fukushima – and there's some possibility that what blew out of the #3 core that day could wipe out life on earth.

        If it did not wipe out earth – now would be a convenient time to stop messing with MOX, and indeed stop messing with all nuclear reactors.

  • NoPrevarication NoPrevarication

    The 11th of March is on Sunday. Take to the streets. Go to a major local intersection with a poster:

    "Ask me about Fukushima fallout in the U.S" or

    "Who let the Plutonium out?" or

    "Say Goodby to Nuclear Power"

    But for heaven's sake don't just talk about it! Be sure to advertise enenews.

  • jackassrig

    The weak link in the reactor is the bolted top. The temperature rises due to melt down. The steam pressure goes up up and away because the temperature is going up up and away. The bolts loose their strength and the joint parts and ejects the head. The water in the reactor flashs to steam and kaboom. A small volume of water flashes to steam many times the volume of the water. 1200# steam is suddenly let down to atmospheric. Balloon effect the steam, SFP, head, and anything else topside goes out and the bottom of the reactor goes down. Like a recoil in a cannon.

    • HoTaters HoTaters

      Jackassrig, am pretty sure there were photos of #3 early on showing close-ups of sheared-off bolts and the reactor head either off the reactor. Or it had shifted off to one side (maybe not completely fallen off). Came out right around the time the #3 SPF went Kaboom!

      Think maybe it was a video if not still photos. Video most likely ….

    • Those massive chunks of concrete flying 2000 feet up —what could they be except the well head cap above the reactor cap?