Modelling of cementitious backfill interactions with vitrified intermediate-level waste

The calculations indicated that for NRVB, the overall alkaline buffering capacity of the backfill is not expected to be impaired by interactions with vitrified waste; rather the buffering will be to less alkaline pH values (above pH 9) but for a longer period. For the LPB, slightly lower pH values were predicted in some cases. The sorption capacities of the backfills are unlikely to be impaired by interactions with vitrified ILW. Indeed they may be increased, due to the additional C-S-H phase formation. The results of this study suggest that disposal of vitrified ILW in a cement-based disposal system with a high-pH backfill is a potentially viable disposal option.