Modeling and forecasting of radiation situation in the rivers of accidental area of the Chernobyl atomic power plant

Mathematical model was developed in order to forecast the secondary radioactive contamination of rivers in thirty kilometer accidental area of the Chernobyl atomic power plant, coused by radionuclide (RN) washing from contaminated water catchment areas during floodings. The model was used to determine the volume of experimental investigations, conducted in the area and under laboratory conditions, which enabled to accomplish the required forecast (for 90Sr and 137Cs). The role of water protection structures was taken into account when conducting calculations; it lay not only in mechanical or due to sorption processes refarding of RN by dead dikes and filter dams, but also in decrease of maximal rates and therefore in reduction of desorption from the botton. Calculations showed, that ∼ 0.5% 90Sr and ∼ 0.1% 137Cs in dissolved state would be washed out from each water catchment during spring flood