Homogenization of engineered barriers, simulations verified against Canister Retrieval Test data

The homogenization process in a buffer of KBS-3 design is here studied. An analytical model capable of predicting the average void ratios at full water saturation in the bentonite block and pellet slot is presented. It is found that pressure difference between the block and pellet slot together with the character of the wetting governs the homogenization. Simulations of the Canister Retrieval Tests experiment, using both the finite element solver Code_Bright and the analytical model show that the models agree well with the experimental data. The obtained responses when simulating two extreme wetting scenarios, fast or slow wetting, using Code_Bright and the analytical model also show good agreement.

► The homogenization process of the bentonite buffer in a deposition hole of the Swedish KBS-3 design is here studied.
► Solutions from an analytical model and finite element THM-models (CODE_BRIGHT) are presented.
► The homogenization is found to be governed by wetting process character and magnitude of pressure difference in the buffer.
► The CODE_BRIGHT and analytical solutions agree well with data from the full scaled Canister Retrieval Test experiment.
► Good agreement between CODE_BRIGHT and the analytical model is obtained when two extreme wetting scenarios are studied.