Deep geological repositories - Geosciences in the site selection process
Convener: Vanessa Montoya | Co-conveners: Koen Beerten, Andreas Reinicke, Alwina HovingECSECS

Geoscience knowledge is essential to investigate safety requirements that are established by national agencies to construct a geological disposal for high-level and/or long-lived radioactive waste in a specific selected site. Safety requirements include isolation of the nuclear waste from humans and the accessible biosphere, containment by retention and retardation of contaminants, limited water flow to the geo-engineered facility and long-term geological stability of the site. Experiences in many countries have shown that acceptable conditions for selecting a construction site can be found in diverse rock types as granites, metamorphic basement rocks, plastic clays, indurated claystones, evaporites, porous volcanic tuffs and highly compacted volcanic tuffs.
Geoscientist are tackling challenging issues to support the site selection process. These include hydraulic testing in low permeability formations, appropriate selection of borehole testing fluids, porewater characterization, radionuclide-rock and rock-water interactions, geo-mechanical testing of clay rocks, characterization and classification of fractures in crystalline rock, fracture network modelling, development of long-term site evolution models, management of large amount of data obtained during the site characterization phase, integration of diverse geoscientific data and the development of plausible future evolution scenarios. For this reason, in this session, relevant topics included, but not limited are:
• Data digitalization/management and parameter collection
• Development of new methodologies for site characterization (i.e., rock characterization)
• Laboratory-scale, underground research laboratories and large-scale mock-up experiments
• Radionuclide migration in rocks
• Natural analogues and/or full scale in situ testing
• Modelling and upscaling of coupled processes: Thermo-Hydro-Mechanical-Chemical/Biological (T-H-M-C /B)
• Repository induced effects (i.e., gas formation/reactivity, temperature changes, induced seismicity and chemical reactions).
• Long-term geological evolution scenarios including natural processes which may impact the geosphere over very long timescales, including tectonics/neotectonics (uplift, subsidence, faulting), climate change and its effect on groundwater flow and composition (i.e., global warming/cooling with permafrost development), and climatic and/or tectonic induced erosion (i.e. glacial erosion)
• Code and model development and uncertainty treatment