Who Was Hisashi Ouchi? Hisashi Ouchi was a Japanese technician working at the Tokaimura nuclear facility in Japan. On September 30, 1999, he became the victim of one of the most severe radiation accidents in human history. He was one of three workers exposed during the JCO nuclear accident, and his injuries became widely known due to the extreme nature of the radiation exposure. What Happened to Hisashi Ouchi? Ouchi was exposed to an estimated 17 Sieverts (Sv) of radiation—far beyond the fatal dose of 8 Sv. The accident occurred when a team was preparing fuel for a fast breeder…