高レベル放射性廃棄物固化処理用Li_2O-Al_2O_3-SiO_2系ガラスおよびガラスセラミクスの開発

For the purpose of developing glass-ceramics which can incorporate and stabilize high-level radioactive nuclear waste, glasses and glass-ceramics of the Li2O-Al2O3-SiO2 system containing sodium molybdate were prepared and their properties were examined. Glass-forming region, liquidus temperature, solubility of molybdate, crystallization temperature and thermal expansion coefficient were measured. The liquidus temperature and viscosity of glasses were lowered by adding sodium molybdate. The glass could contain 2~3 wt% molybdate, which led to the estimate that the glass can admit about 20 wt% nuclear waste. Glass-ceramics with a negative thermal expansion coefficient was prepared, in which main crystalline phase was a low expansion β- eucryptite. The resultant glass-ceramics consisted of coarse grains and was not so strong mechanically. Thus, it was indicated that the fine-grained glass-ceramics with suitable properties would be developed when preper nucleation agents were chosen