Immobilization of Radioactive Cesium in Pyrolytic-Carbon-Coated Zeolite

All waste forms currently being developed for radwaste disposal have difficulty immobilizing cesium. A new waste form was developed to dispose of cesium by loading up to 5 wt% Cs onto zeolite granules. These zeolite particles are then heat‐treated and coated with pyrolytic carbon and/or BC to completely immobilize cesium. The leach rate of cesium from pyrocarbon‐coated zeolite is 3 to 4 orders of magnitude less than for other waste forms. We therefore propose that cesium be removed from the primary waste stream and loaded onto zeolite granules for subsequent coating. The total waste form (primary waste form plus coated zeolite) would have acceptable leach resistance for all radwaste components and be extremely leach‐resistant for cesium.