Improved cement barriers applied in nuclear wastes

Laboratory scale experiments have been carried out to compare the rate of release of radionuclides from cemented waste forms with unprocessed powder waste in preformed cement containers. Attempts to improve the properties of cement matrices used as a barrier against the release of radionuclides from waste materials focus on chemical treatment and polymer impregnated cement (PIC). The results obtained show that the incremental release of cesium per day per cm 2 of exposed surface area was decreased for processed cement-waste forms (chemically treated and / or polymer impregnated) compared with unprocessed cement-waste forms. Further improvement in the incremental release was achieved using unprocessed powder wastes in cement containers. Chemical treatment of waste material improved the cumulative percent release of cement — waste forms by a factor of four for cesium and by ten for cobalt.