LEACHING OF ¹³⁷Cs FROM SPENT ION EXCHANGE RESINS IN CEMENT-BENTONITE CLAY MATRIX

Ilija Plecas

Vinca Institute of Nucleare Sciences, P.O.BOX 522 11001 Belgrade, Serbia and Montenegro

Abstract

The leaching rate of ¹³⁷Cs from the spent cation exchange resins in cement-bentonite matrix has been studied. The solidification matrix was a standard Portland cement mixed with 290-350 (kg/m³) spent cation exchange resins, with or without 2-5% of bentonite clay. The leaching rates from the cement-bentonite matrix for¹³⁷Cs:(3.2-6.6)´10^-4(cm/d), after 125 days were measured. From the leaching data the apparent diffusivity of cesium in cement-bentonite clay matrix with a waste load of 290-350 (kg/m³) spent cation exchange resins was measured for ¹³⁷Cs: (1,5-26)´10^-5(cm²/d), after 125 days. The results presented in this paper are part of the results obtained in a 20-year mortar and concrete testing project, which will influence the design of radioactive waste management for a future radioactive waste disposal center.