Added 2 new A* pages:I suppose pretty much everyone is following the situation with the overheating nuclear power plant in Japan, damaged in Friday's earthquake. Since I mentioned it early Saturday, they've had two more explosions, and now a fire, which has apparently led to higher radiation levels and even radioactivity "being released directly into the atmosphere." After the fire, radioactivity in the area was measured "up to 100 times the normal levels," which might be about .1 cSv per day: not a situation you want to have for very long. You'd have to get about 2000 times worse than that before it started making people seriously physically ill in the short term, but (still according to that Wikipedia article I linked on Friday) just 19 days of that, for instance, might increase your chance of getting cancer over your lifetime by 2%.|
These are a couple days old now but still good, I think: this article has some solid information about the situation in a reactor of the type in question, mentioning for instance that this reactor's are old (they were near retirement), which means they take longer to cool down, prolonging high temperatures and thus meltdown risk; and this article mentioned that the earthquake (which has since been upgraded from 8.9 to a full 9.0 on the Richter scale, meaning it was about 1.4 times as powerful as initial measurements had indicated) sped up the Earth's rotation by 1.6 microseconds (millionths of a second)--that tends to happen with big earthquakes: the 2004 Sumatra quake, for instance, advanced the planet's rotation a comparatively whopping 8.6 microseconds.
UPDATE: Ah, that first article has been updated with more specific information: the radiation spiked at "a radioactive dose in one hour at the site 400 times the amount a person normally receives in a year" for six hours. If they're basing that on 0.36 cSv per year, then that would have been 864 cSv (144/hour), which would have been a fatal amount (500 cSv is considered the point at which a 50% fatality rate is incurred)...but then they quote a guy as saying "a person would have to be exposed to that dose for 10 hours for it to be fatal," so maybe they were using something more like the low end estimate for yearly gamma ray exposure, 0.1 cSv, which would come out to 240 cSv (40/hour). Even that's quite a bit, and hopefully nobody took that much (presumably you would have had to have been at the plant itself to get that exposure), or they'll be very, very sick right now.
UPDATE again: The article above was an Associated Press article; now I see there's a Reuters article that says the high point of the radiation leak was "400 millisieverts per hour"; a millisievert is 0.001 Sv, or .1 cSv, so 400 of those would come to the 40 cSv/hour exposure I'd guessed above, which means they were using 0.1 cSv as the normal annual exposure figure. Radiation levels ten times normal were measured in Tokyo (which is a little under 250 km, or about 150 miles, from Fukushima--where the plant is said to be located--if my eyeball of Google maps is correct). Both articles have quoted people in Japan as mentioning that what really makes the radiation threat worrying is that you can't see it. On the positive side, the AP article says that a Chernobyl-like scenario where gas from the reactor core explodes directly into the environment is very unlikely, since the reactors at this plant are inside radiation containment structures that did not exist at Chernobyl. Back on the freaking-us-out side, the Reuters article quotes someone as saying the water in the reactor would take 7-10 days (starting from early Saturday, presumably) to boil away, exposing the fuel rods and making a leak possible.