其他摘要：This research was conducted in radiologically contaminated forests at Fukushima Prefecture from 2011 to 2014 to reveal the contribution for air dose rate at a height of 1 m in the forests from the various forest compartments, by calculating air dose rates from radiocesium inventories in leaves and branches, the litter layer, the mineral soil layers, and natural radiation. In 2011, air dose rates in forests comprised gamma rays emitted from the canopy layer, litter layer, the surface mineral soil layer (0–5 cm), and natural radiation. However, in 2014, >88% of the total air dose rate in the forest originated from the litter layer, the surface mineral soil layer (0–5 cm), and natural radiation, and emissions from the canopy layer were <3%. These results suggest that after 2014, air dose rate could be calculated from radiocesium inventories of the litter layer, the surface mineral soil layer (0–5 cm), and natural radiation in the forest. In addition, air dose rates calculated at a height of 1 m before and after the removal of the litter layer demonstrated that the removal of the litter layer caused a decrease in the air dose rate in forest, even 4 years after the Fukushima Dai-ichi Nuclear Power Plant (FDNPP) accident. It is of interest that the reduction effect of the air dose rate by the removal of the contaminated litter was larger than that when increasing the air dose rate by decreasing the shielding effects caused by the forest litter.
关键词：空間線量率;放射性セシウム;除染効果;森林除染;東京電力福島第一原子力発電所事故
其他关键词：air dose rate;radiocesium stock;decontamination effect;decontamination in forest;Fukushima Dai-ichi Nuclear Power Plant accident
