Limits of decontamination in rural areas radioactively contaminated by TEPCO nuclear power plant accident and new concept for recover planning

Abstract

This is an empirical study on the actual condition of pollution and decontamination in Iitate Village, Fukushima Prefecture, in the affected area of radioactive contamination released by Tokyo Electric Power Fukushima Daiichi Nuclear Power Plant caused by the Great East Japan Great Earthquake of March 2011. I have clarified the air dose rate in residential area, housing, field, and mountain area around housing. Although there is a decline in spatial dose due to natural decay and decontamination, it is not an environment suitable for residence and agriculture work. I investigated the housing which was released from evacuation. According to the survey in 2017, although the dose in the housing tends to be greater in high space, it is less than 0.6 μSv/h. However, the room adjacent to the forest has a dose of about 1.4 times that of the central room. The surface of the residential land is 0.65 μSv/h on average, exceeding the regulation standard value of the radiation control area. In the forest soil surrounding the residential land after decontamination, radioactive cesium is still 40, 000 Bq/kg. Despite this contamination situation, the evacuation designation was cancelled at the end of March 2017 under unreasonable circumstances. Villagers who went back home had no choice but to produce vegetables in farmland where pollution continues, even though they were decontaminated. Radioactive Cs is also contained in decontaminated agricultural land. It is unreasonable to make agricultural products on land contaminated with Cs. Fortunately, the transition rate of Cs is extremely low, and it is not a problem for the elderly to eat. However, this absurdity continues. Products of contaminated forests cannot be eaten in the foreseeable future, and rich agricultural livelihoods have been lost. New land use planning methods, including the prohibition of land use of radioactively contaminated forests, are needed.