RATE-CONTROLLING STAGES OF THE MIGRATION OF WATER-SOLUBLE RADIONUCLIDE SPECIES IN SOILS

Abstract

The structure and composition of hot particles from soils of the Chernobyl exclusion zone were studied. Regularities that govern the generation of water-soluble Cs-137 and Sr-90 species in soils contaminated by fuel particles borne by the Chernobyl accident were experimentally studied. The kinetic parameters of the formation of the water-soluble species were determined. Cs-137 and Sr-90 solid diffusion through fuel particulates is the rate-controlling stage of aqueous radionuclide migration. The experimental evidence was used to estimate diffusion coefficients. The kinetic parameters of the transformation of exchange-sorbed species of fission products to water-soluble species were determined. The period of 1996-2016 is the most dangerous in terms of the inclusion of Cs-137 and Sr-90 into biogeochemical and food chains.