Mathematical modeling of environmental dynamics in Fukushima Prefecture

福島県内の環境動態数理モデル

北村 哲浩   ; 操上 広志  ; 小田 好博 ; 中間 茂雄 ; Malins, A.  ; 山田 進  ; 奥村 雅彦   ; 町田 昌彦  

Kitamura, Akihiro; Kurikami, Hiroshi; Oda, Yoshihiro; Nakama, Shigeo; Malins, A.; Yamada, Susumu; Okumura, Masahiko; Machida, Masahiko

東京電力福島第一原子力発電所の事故後に福島県浜通り側の土砂及びセシウム137分布を予測する複数の解析モデルを開発し、福島県浜通り側の陸域, 河川, ダム湖内の土砂及びセシウム137の侵食、移動および堆積をシミュレートした。さらに、土壌の遮蔽効果を考慮した空間線量率の解析を行った。各モデルの特徴と実測値と整合性について総合的に報告する。

Radioactive cesium, which strongly adheres to soils, is one of the major concerns regarding health physics in Fukushima today. It migrates mainly by soil erosion and subsequent sediment transport within surface water during times of widespread flooding. In order to predict the future distribution and resulting air dose rate at any location in Fukushima, we have prepared a number of mathematical models for radioactive cesium transport with different space and time scales. In this presentation we cover our prediction methodology, ranging from sediment and radioactive cesium movement to resulting long term air dose rate changes. Specifically, we present simulation results of sediment movement and radioactive cesium migration using semi-empirical and physics based watershed models, and that of sediment and radioactive cesium behavior in dam reservoirs using one and two dimensional water system simulation models. We also present some simulation results on air dose rate at a particular location and compared with direct measurement value.