A Modeling approach to estimate H discharge from rivers; Comparison of discharge from the Fukushima Dai-ichi and inventory in seawater in the Fukushima coastal region

モデルを用いた河川からのトリチウム流出量の推定; 福島第一原子力発電所と福島沿岸域における海水中インベントリとの比較

佐久間 一幸   ; 町田 昌彦  ; 操上 広志  ; 岩田 亜矢子; 山田 進  ; 飯島 和毅  

Sakuma, Kazuyuki; Machida, Masahiko; Kurikami, Hiroshi; Iwata, Ayako; Yamada, Susumu; Iijima, Kazuki

Estimation of H discharge from river catchments is important to evaluate the effect of Fukushima Dai-ichi discharge and future planned H release to the ocean on the coastal environment. Using a previously developed model based on the tank model and observed H concentration in river water, the H discharge from the Abukuma River and 13 other rivers in the Fukushima coastal region were estimated from June 2013 to March 2020. The annual H discharge from catchments of the Abukuma River and 13 other rivers in the Fukushima coastal region during 2014-2019 were estimated to be 1.2-4.0 TBq/y. These values were approximately 2-22 times larger than the annual H discharge from the Fukushima Dai-ichi after 2016, indicating the significance of naturally derived H discharge from the catchments through the rivers. This estimation is expected to be useful to evaluate and predict H concentrations and inventories in the Fukushima coastal region for consideration of planned H release to the ocean.