Nuclear waste glass interfaces after one year burial in STRIPA part 2: Glass/bentonite

The effects of bentonite on the surface behaviour of two nuclear waste glasses are studied after up to one year in-situ burial in the STRIPA mine. Cation exchange of Ca, Mg, Al and Fe from the bentonite for primarily Na and B is found to produce a glass surface that has three silicate-rich layers. The larger concentration of M2+ and M3+ cations and the high silica content of the reaction layers result in a considerably retarded rate of ion exchange after the formation of these layers during the first three months of burial.