HOSHI Masaharu Hiroshima U.Res.Inst.Radiat.Biol.Med.Prof., 原爆放射能医学研究所, 教授 (50099090)
NAKANISHI Takashi Kanazawa U Faculty of Science Prof., 理学部, 教授 (00019499)
YAMAMOTO Masayoshi Kanazawa U Faculty of Science A.Prof., 理学部, 助教授 (10121295)
MITSUGASHIRA Toshiaki Tohoku U.Inst. Material Res. A.Prof., 金属材料研究所, 助教授 (30005938)
IMANAKA Testuji Kyoto U.Res.Reactor Inst. Lecturer, 原子炉実験所, 助手 (90109083)
Environmental impact of the JCO criticality accident was investigated by "Environmental radioactivity research group" and "human effect research group" composed of about 60 members. More than 400 environmental samples (soil, plant leave, chemical reagent, metal, coin, table salt, sugar, stainless steel, fluorescent lamp, gold items etc.) were collected in and around the JCO campus. Concentrations of neutron-induced radionuclides and fission products were measured as a function of distance from the site. Most of the results were reported in "Journal of Environmental Radioactivity, Vol. 50, 2000" as the special issue on Tokai-mura accident. Measurements of long- lived nuclides are still continued in some laboratories. Result of discussion in "The 2_<nd> summer school on environmental radioactivity and radiation" held in June, 2000, was published as "What should be done by nuclear scientists in the case of nuclear accident". Measured values of each sample will be opened as "data base of Tokai- mura accident" with details on sampling map and investigator etc. Results of two research goups have been presented in number of domestic and international symposium.