Spent Fuel Pool(s) Near Boiling Point (Again)

The good news is that lighting at Fukushima I has been restored, and all six reactors at Fukushima I have had power restored, which helps both repair efforts and cooling.

But then the bad news starts. The IAEA says the site is still leaking radiation, the source of which they’re not sure of. There have been NO reports of radiation sickness).

Another Reuters report says the Japanese government says chance that the spent fuel pools will reach re-criticality is “low,” which means either that it’s still not zero or that the government is repeating talking points from last week. The latter seems likely to me than anything, but the two are not mutually exclusive.

Worse, Reuters sent out a breaking news alert that at least one spent fuel pool at Fukushima I is heating up again — and currently near the boiling point. When I went to the Reuters site, I couldn’t find the report, but I discovered that the both reactors 2 and 3 have abnormalities visible — “white smoke” in the case of #2, and “white haze” in the case of #3. Both are likely to be steam from the spent fuel pools.

Steam comes from boiling water, in case you were wondering. However, under some atmospheric conditions, water vapor can show up at much lower temperatures than boiling — so in practical terms steam is far from de facto proof of boiling.

There are spent fuel pools at each reactor, and the bad news is that if any of the six of them at Fukushima I were boiling, we would expect it to be the one at Reactor #4, which apparently has a recently decommissioned set of 548 fuel assemblies, which are fresher, more fissionable and hotter. These were removed and placed in the Reactor #4 spent fuel pool when #4 was shut down for routine maintenance before the earthquake.

Does any of this mean anything? Likely, not for anyone except the workers at the plant. With power restored, cooling will surely be managed effectively.

It’s even possible that the report of the fuel pool(s) at the boiling point preceded the restoration of power, and therefore it’s now completely irrelevant. But we won’t know that for a while yet.

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