Japan's worst nuclear radiation accident took place at a uranium reprocessing facility in Tokaimura, northeast of Tokyo, on 30 September 1999. The direct cause of the accident was cited as the depositing of a uranyl nitrate solution--containing about 16.6 kg of uranium, which exceeded the critical mass--into a precipitation tank. Three workers were exposed to extreme doses of radiation. Hiroshi Ouchi, one of these workers, was transferred to the University...