Construction of river transfer models for MOGRA

陸域挙動予測モデルMOGRAのための河川移行モデル

林 寛子*; 松岡 俊吾*; 高橋 知之*; 天野 光

Hayashi, Hiroko*; Matsuoka, Shungo*; Takahashi, Tomoyuki*; Amano, Hikaru

陸域挙動予測モデル-MOGRAのための河川移行モデルとして、2つの動的コンパートメントモデルの比較解析を行った。1つは存在形態が1成分のモデル、もう1つは存在形態が溶存態及び懸濁態の2成分モデルである。モデルパラメータは、実際に久慈川等で観測された値を用い、流域がCs-137で汚染されたと仮定した。2つのモデルによる解析結果は、河床へのCs-137の沈降速度が小さい場合は差が見いだされなかったが、沈降速度が大きい場合には、結果に明らかな差が生じた。

Two dynamic compartment models were constructed as basic river models for MOGRA (Migration Of GRound Additions), an environmental-load effect predicting code. One is 1 component river model, in which radionuclides in particulate form and dissolved form are considered to be in equilibrium in the river water. Another one is 2 component river model, in which particulate form and dissolved form are considered to be different component and are separately compartmentalized. In each model the river sediment is set in a compartment, and the sedimentation of particulate form and resuspension of radionuclides in the river sediment are taken into account.To verify the analysis function of the constructed models, calculation conditions were set using data of Cs-137 concentration in the river water derived from Kuji river, Japan, and analysis was carried out. Comparing two models, almost no difference is seen when sedimentation velocity is low, while there is apparent difference when sedimentation velocity is high.