Abstract
In the multibarrier system of repositories for radioactive and chemical wastes, compacted betonites may be used as barriers. A research programme dealing with the determination of swelling pressures of compacted bentonites in contact with high-saline brines was conducted by the Gesellschaft für Anlagen- und Reaktorsicherheit GmbH (GRS). Factors found by the GRS team to influence the swelling pressure, besides the density and the microstructure of the compacted bentonite, are the brine composition and the applied hydrostatic pressure. For brines with very high salt content, the existing models are not able to predict or reproduce the experimental results. In order to either extend existing models or to create a new model, the governing parameters for the swelling pressure must be identified. The GRS team has developed new experimental and theoretical approaches for the modeling of swelling pressures.
