It’s now 8:00pm EST on 3/12/11. If you read through press accounts of the situation at Fukushima, you will find two trends. First, credible outside experts (like Michio Kaku) are saying that a worst case scenario is unfolding or has already transpired. Second, Japanese government officials are minimizing the problem. This is the information profile of a disaster in progress. The government denies everything (while evacuating a 20km radius), while outside experts make dire predictions.
I’m watching the situation with some concern because of the current prevailing winds. There is much more nuclear material at Fukushima than there was at Chernobyl, and in the event of a large release, 10 times the radiation released by Chernobyl could be blown straight into downtown Tokyo (see this analysis from rt.com). I’ve read plenty of judgments that this could never happen because the reactors are surrounded by 6 inches of steel plate. But a nuclear reactor can easily get up above 5,000 degrees Fahreneit — more than hot enough to melt through steel. And if this happens, the seawater that has been pumped through the reactor chamber would only help to vaporize and widely disperse radioactive material.
Everything I’ve read assures me that this is unlikely. But if there’s even a 1% chance — would you want to be in Tokyo? My thoughts are with everyone downwind of Fukushima right now.
Some more info — after the earthquake, the reactors were shut down by inserting control rods. However, there are radioactive byproducts of fission that remain for a long time after the rods are inserted and the reactor is “shut down”. The ongoing decay of these byproducts produces considerable heat that still needs to be removed. If enough seawater can be pumped through the reactors, they shouldn’t have any further problems. But that’s a big if.
As Deanah put it, they have “a half life of their own.” Heh.