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Hirouchi, Jun; Takahara, Shogo; Komagamine, Hiroshi*
Journal of Radiological Protection, 42(4), p.041503_1 - 041503_12, 2022/12
Times Cited Count：1 Percentile：29.26(Environmental Sciences)Sheltering is one of the countermeasures against radiation exposure during nuclear accidents. The effectiveness of sheltering for inhalation exposure is often expressed by the reduction factor, which is defined as the ratio of the indoor to the outdoor cumulative radioactivity concentrations or doses. The indoor concentration is mainly controlled by the air exchange rate, penetration factor, and indoor deposition rate. Meanwhile, the air exchange rate depends on surrounding environmental conditions: the wind speed, leakage area normalized by the floor area of the house, and gross building coverage ratio. In this study, the ranges of the uncertainty of the reduction factors for particles and I
were investigated under various environmental conditions, and sensitivity analyses were conducted to understand the parameter with the most influence on the uncertainty of the reduction factor. From the results of the uncertainty analyses, the calculated reduction factor was highly variable depending on the environmental condition and the airtightness of the houses. The uncertainty ranges of the reduction factor for particles and I were up to 0.9 and 0.3, respectively, and were smaller for newer houses. From the results of the sensitivity analyses, the wind speed was the most influential parameter on the reduction factor. Additionally, the wind speed was less influential for the reduction factor in newer houses.
Ikenoue, Tsubasa; Shimadera, Hikari*; Kondo, Akira*
Journal of Environmental Radioactivity, 225, p.106452_1 - 106452_12, 2020/12
Times Cited Count：4 Percentile：14.27(Environmental Sciences)This study focused on the uncertainty of the factors of the Universal Soil Loss Equation (USLE) and evaluated its impacts on the environmental fate of 
Cs simulated by a radiocesium transport model in the Abukuma River basin. The USLE has five physically meaningful factors: the rainfall and runoff factor (R), soil erodibility factor (K), topographic factor (LS), cover and management factor (C), and support practice factor (P). The simulation results showed total suspended sediment and Cs outflows were the most sensitive to C and P among the all factors. Therefore, land cover and soil erosion prevention act have the great impact on outflow of suspended sediment and Cs. Focusing on land use, the outflow rates of Cs from the forest areas, croplands, and undisturbed paddy fields were large. This study indicates that land use, especially forest areas, croplands, and undisturbed paddy fields, has a significant impact on the environmental fate of Cs.
*; Fusaeda, Shigeki*
JNC TJ1400 2000-004, 245 Pages, 2000/02
JNC-TJ1400-2000-004.pdf:8.57MB
no abstracts in English
*; Fusaeda, Shigeki*
JNC TJ1400 2000-003, 94 Pages, 2000/02
JNC-TJ1400-2000-003.pdf:4.63MB
no abstracts in English
Yotsuji, Kenji; Tachi, Yukio; Hato, Shinji*
no journal, ,
We carried out the uncertainty analyses for the porewater chemistry and distribution coefficients in compacted bentonite using the PHREEQC code.
Ikenoue, Tsubasa; Shimadera, Hikari*; Kondo, Akira*
no journal, ,
This study focused on the uncertainty of the factors of the USLE and evaluated its impacts on the environmental fate of Cs simulated by a radiocesium transport model in the Abukuma River basin. In the USLE, soil loss is expressed as a product of factors representing rainfall (R factor), geology (K factor), topographic (L 
S factor) and land cover and soil erosion prevention act (C P factor). The simulation results showed total outflows of suspended sediment and Cs were the most sensitive to C P factor among the all factors. Therefore, land cover and soil erosion prevention methods have the great impact on outflow of suspended sediment and Cs.
Nittono, Akira*; Ikenoue, Tsubasa; Shimadera, Hikari*; Matsuo, Tomohito*; Kondo, Akira*
no journal, ,
The Fukushima Daiichi Nuclear Power Plant accident caused extensive Cs contamination. Long-term simulations have been conducted to predict the amount of Cs outflow from river basins to the ocean. However, there are uncertainties about the influences of rainfall, tree types and dams to the Cs outflow. This study focused on how much these three factors influence the Cs outflow in eastern Fukushima river basins from 2011 to 2040. The Cs outflow varied by -10 to +17% depending on precipitation, and by -16 to +19% depending on tree species, decreased by 21% by dams.
