Radioactive Waste

Deep geological disposal is one of most favored solutions for the isolation of high level nuclear waste. It is also the one that requires major geotechnical input. The natural (host rock) and engineered barriers (generally made up of swelling clays) will be subjected to simultaneous thermal, hydraulic and mechanical (THM) phenomena triggered by the heat-emitting nature of the nuclear waste, the swelling character of the unsaturated clay barrier, and the highly confined conditions of the isolation system. The THM processes described above and their mutual interactions will control the evolution and long term response of the whole isolation system; therefore a good understanding of the main THM phenomena are required for a safe design of HLW repositories. The introduction of new types of heterogeneous pellet-based engineered barriers and the migration of designs towards higher temperatures provide fresh challenges to geotechnical engineering in a multi-physics context.