Mathematical modelling of immobilization of radionuclides 137Cs and 60Co in concrete matrix

Transport phenomena involved in the leaching of a radioactive material from a cement composite matrix are investigated using an empirical method employing a polynomial equation. 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, have been developed. Transport phenomena involved in the leaching of a radioactive material from a cement composite matrix are investigated using an empirical method employing a polynomial equation. In our experiment we have analized 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-year mortar and concrete testing project, which will influence the design of the engineered trenches system for a future central Serbian radioactive waste storage center. (C) 2010 Elsevier Ltd. All rights reserved.