An essential item for the long-term safety of high-level waste underground repositories is the backfilling and sealing of access shafts and connection galleries. The main objective of RESEAL II is to demonstrate on a representative scale that the sealing of a shaft i.e. the "experimental" shaft of the HADES underground laboratory, with a low permeability powder/pellets mixture of bentonite avoids preferential migration of water, gas or radionuclides either through the seal of through the excavation disturbed zone around it. The mechanical stability of the seal under accidental overpressure conditions will be also tested. A tracer diffusion in the host clay formation around the seal will allow to study, by modelling, the migration parameters of the excavation disturb ed zone. Hydro-mechanical models will be applied for the interpretation of the test results and consequently to demonstrate our understanding of the seal behaviour.
Funding SchemeCSC - Cost-sharing contracts
91191 Gif Sur Yvette
92298 Chatenay Malabry