Temperature effect on structural evolution of aluminosilicate gels formed during borosilicate nuclear waste glass corrosion

Abstract

Temperature effects on the interfacial reactions, transport, atomic and microstructural evolutions of hydrated calcium aluminosilicate porous gel structures formed during the dissolution of borosilicate nuclear waste glasses were studied by using reactive molecular dynamics simulations. The gel structures with experimental compositions were generated to reproduce different porosity and pore morphologies, which were then sequentially hydrated and the studied at two temperatures to understand their structural evolutions. These results provide insights into the atomic level details of the gel structure evolution as well as calcium dissolution and water transport, which help to understand the gel layer characteristics that are critical for the residual dissolution rate and long-term chemical durability of borosilicate glasses as a media for immobilization of nuclear waste materials in geological time scales.