FREUDENBERGITE - A POSSIBLE SYNROC PHASE FOR SODIUM-BEARING HIGH-LEVEL WASTE

Earlier studies have shown that the presence of excess sodium in high- level nuclear waste can give rise to increased leachability when the w aste is incorporated in Synroc-type titanate ceramics. Freudenbergite (Na2A12Ti6O16) can incorporate sodium and it exhibits satisfactory lea ching resistance in water and reasonable resistance to radiation. From X-ray diffraction studies, freudenbergite is compatible with the othe r phases in Synroc. Thus, Synroc containing freudenbergite as an addit ional phase offers potential for immobilizing sodium accompanying high -level nuclear fuel reprocessing waste.