Unsaturated flow simulations with ALLIANCES platform: from validation to application

Within the scope of high and intermediate radioactive waste disposal performance calculations, unsaturated flow computation in geological porous media is an important task. Indeed, at the early stage of the repository life, unsaturated process controls the water arrival time to the waste and then radionuclides release. Later, as long as the disposal remains unsaturated, radionuclide transport occurs inside an unsaturated media. Among other phenomenological processes, the ALLIANCES platform allows dealing with unsaturated flow computation and integrates numerical codes solving the Richard's equation allowing code results inter-comparison on a given problem. In this paper we present some unsaturated flow computations performed in the framework of the ALLIANCES validation on analytical solutions and on one laboratory experiment. A three-dimensional calculation application to the disposal plug shaft saturation after closure will complete the demonstration of the ability of ALLIANCES to deal with unsaturated flow problems of concern for radioactive waste disposal performance calculations. (authors)