Curing Time Effect on the Fraction of ¹³⁷Cs From Cement-Ion Exchange Resins-Bentonite Clay Composition

To assess the safety of disposal of radioactive waste material in cement, curing conditions and time of leaching radionuclides ¹³⁷Cs have been studied. Leaching tests in cement-ion exchange resins-bentonite matrix, were carried out in accordance with a method recommended by IAEA. Curing conditions and curing time prior to commencing the leaching test are critically important in leach studies since the extent of hydration of the cement materials determines how much hydration product develops and whether it is available to block the pore network, thereby reducing leaching. Incremental leaching rates R_n (cm/d) of ¹³⁷Cs from cement-ion exchange resins-bentonite matrix after 180 days were measured. The results presented in this paper are examples of results obtained in a 20-year concrete testing project which will influence the design of the engineer trenches system for future central Serbian radioactive waste storing center.