Elemental Composition of Glass Used to Capture Nuclear Waste Makes a Difference
To better understand the structure and durability of aluminoborosilicate glass used to capture nuclear waste, Pacific Northwest National Laboratory scientists conducted systematic experiments with aluminum, boron, sodium and silicon, the four major components of nuclear waste glass. The team synthesized glasses with different concentrations of these elements and then, using the solid-state nuclear magnetic resonance capabilities at DOE’s Environmental Molecular Sciences Laboratory at PNNL, along with flow-through dissolution experiments, they investigated how structural changes in the glass affected their dissolution as a function of pH and temperature. Results indicate that the dissolution rate for glass is controlled by rupturing the aluminum to oxygen bond or the silicon to oxygen bond. Determining how glass breaks and dissolves is paramount for improving the prediction of nuclear waste release from glass and it advances fundamental understanding of how minerals weather and cycle these elements in subsurface environments.
Pierce EM, LR Reed, WJ Shaw, BP McGrail, JP Icenhower, CF Windisch, Jr, EA Cordova, and J Broady. 2010. “Experimental Determination of the Effect of the Ratio of B/Al on Glass Dissolution along the Nepheline (NaAlSiO4)-Malinkoite (NaBSiO4) Join.” Geochimica et Cosmochimica Acta 74(9):2634-2654.