Nuclear Accidents in Fukushima, Japan, and Exploration of Effective Decontaminant for the 137Cs-Contaminated Soils

Nuclear accident at the Fukushima Dai-ichi nuclear power plant (FDNPP), which is located 230 km north of downtown Tokyo, was the most recent tragedy in the nuclear society. The total release of radioactivity was estimated to be 6.3 × 1017 Bq, which is approximately onetenth of the total radioactivity released from the Chernobyl (5.2 × 1018 Bq) (TEPCO, 2011). The International Atomic Energy Agency (IAEA) has recently announced the International Nuclear and Radiological Event Scale (INRES) of the Fukushima accident to be level 7.