Immobilization of 137Cs and 60Co in concrete matrix

To assess the safety for disposal of radioactive waste-cement composition, the leaching of Cs-137 and Co-60, from a waste composite into a surrounding fluid has been studied. Leaching tests were carried out in accordance with a method recommended by IAEA. Determination of retardation factors K-F and coefficients of distribution k(d), using a simplified mathematical model for analyzing the migration of radionuclides, has been developed. In our experiment, we have analyzed mechanism of Cs-137 and Co-60 leaching values during a period of 60 days. Results presented in this paper are examples of results obtained in a 25 yr mortar and concrete testing project, which will influence the design of the engineered trenches system for a future central Serbian radioactive waste storage center.