The successful implementation of safe deep geological disposal of spent fuel, high-level waste and other long-lived radioactive waste is one of the currently most pressing environmental challenges in several countries worldwide. Site exploration and assessment are primarily geoscientific tasks that require interdisciplinary collaboration of different geoscientific disciplines, like geophysics, hydrogeology, (hydro-)geochemistry, mineralogy, geomechanics, and geological as well as THMC modelling. Successful and socially accepted site selection and implementation, however, not only depend on geoscientific state-of-the-art results and R&D programs but to a large extent on well-designed public outreach and public involvement/participation activities as well as on suitable regulatory frameworks.
As for other subsurface technologies such as the storage of thermal energy and other energy carriers, or the deposition of chemotoxic waste, barrier integrity is a crucial aspect for the assessment of nuclear waste disposal. Different technical concepts in diverse geological candidate formations are being discussed. Numerical simulations, in conjunction with experimental studies are an integral part of safety and environmental-impact assessment concepts involving barrier integrity as a key component. Reliable comparative analyses of potential technological options require coupled THMC models capturing the particularities of each rock type and associated repository concept to a comparable level of sophistication. Structural as well as process complexity are often met by data scarcity and variability, necessitating the treatment of uncertainties and variability.
Aside from geoscientific and technological aspects this interdisciplinary session also addresses social and regulatory challenges by welcoming contributions from research and technical support organizations, waste management organizations, regulatory bodies, and NGOs. The session provides a platform for the exchange of i) geophysical, geochemical, geotechnical knowledge for assessing the integrity of multi-barrier systems considering equally conceptual, theoretical, computational and experimental aspects as well as ii) safety assessment strategies and tools, disposal concepts, national and transnational public outreach and involvement programs, siting approaches and relevant regulatory frameworks. Presentations related to other subsurface technologies that face comparable challenges are also welcome.