Engineered barrier of bentonite pellets and compacted blocks: State after reaching saturation

摘要

The EB experiment was a large-scale test performed in the Underground Research Laboratory of Mont Terri (Switzerland) for the demonstration of an engineered barrier concept for nuclear waste disposal consisting of the simultaneous use of high-density bentonite blocks and a lower-density bentonite pellets mixture (the granular buffer material, GBM). For that purpose, a gallery was excavated in the Opalinus clay and a dummy waste canister was placed on a bed made of bentonite blocks and surrounded by the GBM material. The bentonite barrier was artificially hydrated with Pearson water and after 10.5 years of operation at isothermal conditions it was considered that the bentonite was completely saturated and the dismantling of the barrier was undertaken. A sampling campaign was done to assess the final state of the bentonite barrier with regards to dry density and water content.