Glasses for energy applications : atomic scale network structure and properties

Abstract

Glass is used for the vitrification of high level waste that results from the reprocessing of spent nuclear fuel. A better understanding of the structure of vitrified wastes may lead to insights into the observed compositional flexibility. It is also the starting point for studies of the self-irradiation behaviour of glasses under long-term repository conditions. Appropriate models need to be employed for the study of glasses when using molecular dynamics. The nature of nuclear waste necessitates an accurate structure prediction for a range of compositions and parameters. To this end, the suitability of established potential sets have been compared. The established potential models were used to investigate the structure of zinc containing sodium silicate glass. Once validated, this structure was used to investigate structural changes observed during simulated self-irradiation, where significant changes were observed on the atomic scale. This will provide the basis for further studies of radiation damage, glass-crystal interfaces and damage across glass-crystal interfaces. In order to further enhance the understanding of potential models, a novel glass of composition LiAlF4 has been successfully described, and may become relevant in the future as a thin film coating in Li-ion batteries.