2017 年 32 巻 4 号 p. 237-243
In this paper, we summarized the state-of-art knowledge of source term, atmospheric dispersion, and deposition of radionuclides during the Fukushima Daiichi Nuclear Power Station accident in March 2011. Six years later from the accident, a large amount of internal and international research activities increased our understanding of total release amount and spatiotemporal radiological plume movement. On the other hand, the mechanism of deposition of radionuclides was still largely unknown particularly in mountainous areas of East Japan. Further investigation is required to obtain the detailed information of fog, drizzle, and weak rain events and the physicochemical information of radiological aerosols during the accident.