KINETICS OF RADIONUCLIDE INTERACTION WITH SUSPENDED-SOLIDS IN MODELING THE MIGRATION OF RADIONUCLIDES IN RIVERS .1. PARAMETERS FOR 2-STEP KINETICS

Four parameters for description of the interaction of radionuclides with suspended solids in mathematical modeling of radionuclide migration in rivers are proposed. The parameters describe two consecutive or parallel steps of the uptake or release of radionuclides by the solids. Two of the parameters are apparent rate constants of radionuclide uptake by the solids (lambda(1), lambda(2)), two are equilibrium distribution coefficients (alpha, beta), describing the equilibrium distribution of a radionuclide between the solution and two kinds of exchange sites in the solid phase. Method for determination of the parameters based on laboratory experiments and computer fit of the results using simple kinetic models are proposed. The applicability of such methods to a set of data on radiocobalt interaction with river sediments is tested.