Leaching of 137Cs from spent ion exchange resins in cement-bentonite clay matrix

The leaching rate of Cs-137 from the spent cation exchange resins in cement-bentonite matrix has been studied. The solidification matrix was a standard Portland cement mixed with 290350 (kg/m(3)) spent cation exchange resins, with or without 2-5% of bentonite clay. The leaching rates from the cement-bentonite matrix for Cs-137:(3.2- 6.6) x 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/m(3)) spent cation exchange resins was measured for Cs-137: (1,5- 26) x 10(-5)(cm(2)/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.