MODELING OF MIGRATION OF CS-137 ACCIDENTALLY RELEASED INTO A SMALL RIVER

Migration of Cs-137 accidentally released with wastewaters from a nucl ear power plant into a system consisting of a wastewater channel and t he Dudvah river in Slovakia was modelled. The SMC model used simulated the river by a series of mixed 'reactors' representing sections of th e river. Input data for the model were obtained partially by measureme nts and partially by calibration of the model using several sets of da ta for activities of river bottom sediments. In this way the space- an d time-averaged value of the coefficient of exchange between suspended solids and bottom sediments in the river was obtained and the sedimen t distribution along the river was refined. The relatively good agreem ent between the measured and calculated activities of Cs-137 in bottom sediments proved that the activities can be modelled reasonably well using the averaged parameters in the model.