2007 年 42 巻 3 号 p. 234-246
The Japan Atomic Energy Agency (JAEA) has carried out expeditions in the Japanese and Russian exclusive economic zones (EEZ) of the Japan Sea for 10 years to clarify seawater circulation and transport processes of radionuclides in the sea. The Japan Sea expeditions by JAEA started with its participation in the Japanese-Korean-Russian joint expeditions of 1994 and 1995. Through 18 expeditions, JAEA succeeded in covering almost all areas of the Japan Sea that can be observed at present. As a result, for the first time, JAEA has made distribution maps of anthropogenic radionuclides in the Japan Sea and outlined the transport processes of radionuclides in the sea. Furthermore, we also obtained the results on water circulation and oceanographic features of the Japan Sea. This review summarizes representative and important results obtained in the Japan Sea expeditions by JAEA. The dataset on the distribution of anthropogenic radionuclides established by this study provides background data in assessing the radiological consequences in cases of radioactive waste disposal in the sea or nuclear emergency response to accidental releases of radionuclides in or near the Japan Sea.