Modelling water and ion diffusion in clays: A multiscale approach

The safety analysis of geological disposal of nuclear waste relies on a comprehensive understanding of the structural and dynamic properties of the geological medium hosting the repository. In this context, a vast research program has been undertaken on the migration of radionuclides (mainly ions) in clays, under the supervision of ANDRA. In parallel to the experimental determination of empirical parameters describing the transport at the macroscopic scale, some theoretical efforts have been made to base such a description on a microscopic view of the transport mechanisms. We review here some of the theoretical approaches developed up to now in our research group, with a particular focus on their complementarity.