No abstract

Understanding composition-structure-property relationships of high-alumina nuclear waste glasses are important for vitrification of nuclear waste at the Hanford Site. Two series of glasses were designed, one with varying Al:Si ratios and the other with (Al + Na):Si ratios based on the international simple glass (ISG, a simplified nuclear waste model glass), with Al 2 O 3 ranging from 0 to 23 mol% (0 to 32 wt%). The glasses were synthesized and characterized using electron probe microanalysis, X-ray photoelectron spectroscopy, small angle X-ray scattering, high-temperature oxide melt solution calorimetry, and infrared spectroscopy. Glasses were crystal free, and the lowest Na 2 O and Al 2 O 3 glass formed an immiscible glass phase. Evolution of various properties-glass-transition temperature, percentage of 4-coordinated B, enthalpy of glass formation-and infrared spectroscopy results indicate that structural effects differ based on the glass series.

No abstract

High-alumina containing high-level waste (HLW) will be vitrified at the Waste Treatment Plant at the Hanford Site. The resulting glasses, high in alumina, will have distinct composition-structure-property (C-S-P) relationships compared to previously studied HLW glasses. These C-S-P relationships determine the processability and product durability of glasses and therefore must be understood. The main purpose of this study is to understand the detailed structural changes caused by Al:Si and (Al + Na):Si substitutions in a simplified nuclear waste model glass (ISG, international simple glass) by combining experimental structural characterizations and molecular dynamics (MD) simulations. The structures of these two series of glasses were characterized by neutron total scattering and 27 Al, 23 Na, 29 Si, and 11 B solid-state nuclear magnetic resonance (NMR) spectroscopy. Additionally, MD K E Y W O R D S aluminosilicates, borosilicate glass, international simple glass, molecular dynamics, nuclear magnetic resonance, scattering F I G U R E 1 Neutron total scattering structure factor spectra obtained from (A-B) experimental data and (C-D) MD simulation for (A, C) ISG-An and (B, D) ISG-AnN glasses.