Control of Nepheline Crystallization in Nuclear Waste Glass

Abstract

Glass frits with high B2O3 concentrations, when combined with high‐alumina concentration nuclear waste, will form glasses with durabilities that are acceptable for disposal (normalized boron release of <1.7 g/L) and predictable using a free energy of hydration model. Glasses with nepheline discriminator values closest to 0.62 showed significant differences in durability between the quenched and heat‐treated versions. Nepheline crystallized in the glass with the lowest nepheline discriminator value. The high‐B2O3 frit was successful in producing glasses without crystallization at waste loadings of up to 45 wt%. The melt rate of this frit was also considerably improved (13.1 g/min).