Re the UCB numbers–if you were to drink your entire annual water allotment in the one single day of high readings, and drink all of it straight from a rainwater cistern rather than your tap, it would amount to about 70 microSv, which is the level of excess radiation dose of staying in Denver, CO [...]

And I quite agree that he (like every cabinet secretary) should be held accountable for what he’s doing as cabinet secretary, and for policies he defends / gives cover for. I just don’t think one should leap to the conclusion he’s a moron.

Look, Steven Chu was a legend already 15 years ago when I was looking at grad schools in physics. He can think his way through laser-laced mazes a lot faster and more accurately than pretty much anyone on this planet. He’s no disgrace to the Nobel Prize in Physics. A cabinet secretary, to keep his [...]

The LATimes also says not all the workers have film badges or dosimeters. “Lost in the tsunami”.

What, TEPCO’s procurement officer can’t even find Google Shopping?

Speechless doesn’t even begin.

wrt flashes of radiation and localized criticality: Oklo.

The Areva presentation linked by fml above is really good, I encourage everyone who is interested in the series of events to read it. It may not be there for long, so you may want to download it soon and read it at your leisure.

These are really nice, thanks!

Thanks! That’s the first I’ve seen that makes clear the “feedwater nozzle” is on top. So I think I declare victory in my description above about water temperatures, temperature gradients, and the pressures in the RPV’s. I don’t know how pressure can be “too low to be measured”. That would normally mean 1 atmosphere. I’m [...]

It’s 4 hours if you keep it at full operating pressure (58 ATM) for the whole time. The report says the pressure is 95% responsible for the failure, so if it gets depressurized fairly early then that risk should be much reduced (and the relevant timescales much increased.) We know they depressurized at some point [...]

I’m going to do the broken-record thing and say that the pressure indications we’ve seen to date all say they are running at 3-4 atm, not at the normal operational level of 58 atm. So seeing 285C is not indicative of simply normal operations. At 3-4 atm water boils at ~125C, which is actually consistent [...]

Figure 1 is particularly interesting, as an example of how three “expert reviewers” can sign their names to an abject failure to assess even an obvious mis-fingerprinting.

Cl-38 is beta (directly to stable Ar-38 so no follow-on decays), and those are much trickier to fingerprint than gamma emitters. Thinking about that, I came across an interesting note on false positive nuclide detection which might be useful to bear in mind when reading the Cl-38 paper. All that said, the Cl-38 decay is pretty [...]

The Cl38 paper is very interesting. It seems to rule out that the Cl38 could be produced by spontaneous neutron emission. I did not see a calculation of the converse, which would be basically the time integral of kg.s of recritical mass needed to account for the amount of Cl38 seen. Did I miss it? [...]

To elaborate a bit on lobster’s 4:03, any physics department with significant nuclear/particle lab research will have gamma spectrometers, which certainly will tell you what’s emitting the radiation. In fact, many undergraduate lab courses have the relevant instrumentation. It’s important to remember that measurable and significant are different words! Spectrometers detect single photons at a [...]

Here’s a link to the original the Seattle arxiv paper mentioned above by PJEvans et al . I posted it in comments several days ago but maybe worth repeating.

This picture of building 4 clearly shows a large green-thing on the upper floor (i.e. not suspended from the ceiling), I guess it’s the crane? If I count courses destroyed by the blasts, building 1 and 4 look pretty much the same–three upper courses on building 1, two and a half in building 4. But maybe [...]

thanks bmaz, you’re probably referring to this comment by 1970cs . The upshot of that comment is that the cladding disintegrates completely before melting. I had always assumed it blistered. I suppose in principle the disintegration remains could melt later, if it got hot enough, but it would be much more likely to powder into the well-below-the-relevant-melting-point [...]

wow– The cladding melts eventually, in the neighborhood of 1400 C. You are absolutely right that it oxidizes and ruptures first; but it’s not too hard to believe that it might splinter and crack without actually dumping the pellets out until later when it melts. But once that happens I can’t see any way the [...]

To Millie Sievert@2:45 and wayoutwest@12:11 The fuel pellets absolutely can melt if it gets hot enough. Whether it gets hot enough is essentially a roll of the dice, but it’s not at all unlikely once the pellets start falling down. (Can someone explain something to me? How could the fuel rods stay intact once they [...]

If they checked out fine and are leaving after a couple of days, they probably did not get 2-6 Sieverts.