Various alternatives of glass waste forms have so far been researched for immobilization of high level radioactive waste. Out of these, two ceramic forms, SYNROC and Supercalcine are the most feasible ones and have the following characteristics; the constituent materials are synthetic minerals and high level radioactive waste elements occupy the cation sites of the crystal structures of the minerals. The two ceramic forms were reviewed with emphasis on compositions, crystalline phases, preparation and physical and chemical stability.
