Leaching of60Co and137Cs from spent ion exchange resins in cement-bentonite clay matrix

The leaching rate of60Co and137Cs 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 cementbentonite matrix for60Co : (4,2–7,0) × 10−5 (cm/d) and137Cs : (3,2–6,6) × 10−4 (cm/d), after 125 days were measured. From the leaching data the apparent diffusivity of cobalt and cesium in cement-bentonite clay matrix with a waste load of 290–350 (kg/m3) spent cation exchange resins, was measured for60Co : (1,1−4,0) × 10−6 (cm2/d) and137Cs : (0,5–2,6) x× 10−4 (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 radio-active waste management for a future Serbian radioactive waste disposal centre.