Tuesday, August 02, 2011

Lethal Dose at Fukushima

credit: NYT
The highest ever levels of radiation have been recorded at Fukushima-Daiichi. 1000 rems/hour (10Sieverts/hr.) is considered a lethal dose. The measurement was made at the base of the ventilation stack for Units 1&2. The actual readings may be even higher since detectors were pegged at their maximum of 10 Sierverts. Its unclear how many workers have been exposed to such extreme levels without knowledge. Workers sent in to confirm the measurements received 400 millirems in just a few minutes of exposure. TEPCo admitted it does not know how much radiation is being emitted by the melting reactors. It has however minimized exposure issues in the past. The government has ordered a halt to sales of beef from Fukushima Prefecture. Some Cesium137 contaminated meat reached the consumer market and has been consumed. Cs₁₃₇ has a biological half life of 70 days. Japanese clearly do not trust TEPCo or the government to keep them reliably informed about radiation dangers, so they are buying dosimeters to do their own testing. What they are finding is that radioactive fallout has spread wider and is higher than officials have disclosed up until now.