Fuel rod fire?

Update

But see also Fuel rod fire? maybe not. IAEA never actually reported the fuel rod fire, and I’ve seen several skeptics in the interval.

While I was asleep, there was a new and unhappy event at Fukushima Daiichi: stored spent fuel rods apparently caught fire. At least right now, this is considerably more exciting than the actual reactor problems. Here’s what the IAEA says:

As reported earlier, a 400 millisieverts (mSv) per hour radiation dose observed at Fukushima Daiichi occurred between units 3 and 4. This is a high dose-level value, but it is a local value at a single location and at a certain point in time. The IAEA continues to confirm the evolution and value of this dose rate. It should be noted that because of this detected value, non-indispensible staff was evacuated from the plant, in line with the Emergency Response Plan, and that the population around the plant is already evacuated.

As they say, that’s in one nasty spot in the plant, and unlike most of the radiation panic, this really is a kind of nasty dose. In the US, we more commonly do dose rates in “rem” — Roentgen Equivalent Man — and one rem is roughly 1/100 Sievert. So this is 40 rem/hr, and that’s not a neighborhood you want to be in a long time. 50 rem is about where you start seeing observable radiation changes, 100 rem in a short time will actually make you sick.

That being said, the dose rate at the gate they report is this:

At 00:00 UTC on 15 March a dose rate of 11.9 millisieverts (mSv) per hour was observed. Six hours later, at 06:00 UTC on 15 March a dose rate of 0.6 millisieverts (mSv) per hour was observed.

That’s 1.2 rem/hr, going down to 0.06 rem/hr.

The frustrating part about writing on this stuff is that people don’t seem to have any middle setting between “everything is fine” and “run in circles scream and shout”. So saying “no, it’s not Chernobyl” is interpreted as “it’s nothing.”

So let’s go ahead and make this clear: no, it’s still not Chernobyl. But no, it’s not nothing.