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.
TRISH HOLAHAN: Okay.
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.
CHAIRMAN JACZKO: Yeah.
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.
TRISH HOLAHAN: Um-hmm.
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.
TRISH HOLAHAN: Okay.
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?
TRISH HOLAHAN: Yes.
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: AUDIO: US gov't experts think melted fuel rods landed in water under Reactor No. 2, causing STEAM explosion -- Pressure dropped dramatically at same time -- Clear indications primary containment lost
Published: March 6th, 2012 at 11:34 am ET