Radioactive Pollution of Fukushima Daiichi Nuclear Power Plant

摘要

Before reoperations of Sendai nuclear power plant, radioactive pollution simulation is depending on SPEEDI. However, in the case of Fukushima nuclear power plant accident, the information disclosure delayed with SPEEDI, and the neighborhood felt fear. Radioactive pollution of Fukushima Daiichi nuclear power plant was analyzed by the simulation in the citizen level for the safety of neighborhood. In this paper, using two methods (particle model and atmospheric diffusion model), Fukushima Daiichi nuclear powerplant accidents were analyzed. Next are the results. Using the particle model, the mountains stretch north to south at altitude 700m from Fukushima nuclearpower plant to Fukushima City. The particles over 0.05mm were blocked on the mountain and slopes, then did not approach Fukushima City. On the otherhand, Fukushima nuclear power plant pollutions approached Iidate village. Using atmospheric diffusion model, a pollution range and a dose of radioactivity fitted considerably almost observation values. The real pollution was derived mostly by the atmospheric diffusion. Mountains around 700m in height are adjacent in the outskirts where pollution spreads and the pollution was limited in a range surrounded by the mountains. The mixture layer height in the atmospheric diffusion model becomes 600m. By classification of the pollution, Fukushima nuclear power plant pollutions concentrated on March 12 to 31, the most pollutions were classified to six parts. The ratio of hydrogen explosions was only 25.4% in total, and the rest was 74.6% with leaks. The ratio of radioisotope for Iidate village with high pollution became 18.5%.