Mathematical Simulation and Analysis of the Behavior of Radionuclides in the System Krasnoyarsk Integrated Mining and Chemical Plant–Enisei–Kara Sea

The equations describing the transport of radionuclides in a system consisting of river water with a suspension and bottom deposits, taking account of the influx of radionuclides with the discharges from the plant and runoff from the basin area, are formulated. The coefficients in the equations are determined by analyzing the data from measurements. On this basis, the flood-plain deposits are dated and the time dependence of the radionuclide discharges over the entire period of operation of plant is determined and the concentration in water and bottom deposits is calculated. The balances between the discharge, the runoff from the basin area, and influx into the bottom deposits, the floodplain, and the Kara Sea are constructed for the past. A procedure is developed for estimating the outflow of mobile forms of radionuclides from the bottom deposits after a sharp decrease of discharges in 1992. The rate of self-purification of the river basin in the future is estimated taking account of this effect and the redistribution of radionuclides between the bottom and flood-plain deposits.