The successful implementation of safe deep geological disposal of nuclear waste and other long-lived waste is one of the most pressing environmental challenges in several countries worldwide. Site investigation and selection are primarily geoscientific tasks that require collaboration of different disciplines, like geophysics, hydrogeology, geochemistry, mineralogy, geomechanics, material science, and geological as well as THMC modelling. The development of DGRs also involves the integration of technical designs, evolving regulatory frameworks, and social acceptance considerations.
Barrier integrity is a crucial aspect for the assessment of nuclear waste disposal. Numerical simulations, in conjunction with experimental studies are an integral part of safety and environmental-impact assessment. Reliable comparative analyses of potential technological options require coupled THMC models capturing the particularities of each rock type and associated repository concept. Structural as well as process complexity are met by data scarcity and variability, necessitating the treatment of uncertainties and variability. The session provides a platform for the exchange on the following topics:
- THMC characterization of materials in natural or engineered barriers in lab- or field-scale experiments
- Hydro-mechanical behaviour of materials with extreme hydraulic properties (e.g. low permeability, high suction) and ranging from ductile viscopolastic salt rocks to quasibrittle fractured rock masses
- Hydraulic and chemical behaviour of geologic and geotechnical barriers
- Computational methods, models and uncertainty quantification for barrier integrity assessment in multi-barrier systems
- Geotechnical aspects of repository construction, operation, and post-closure, e.g. monitoring methods, excavation and support, retrieval/recovery, etc.
- Minimally invasive characterization of geology and underground installations using geophysical and geohydrological methods
Contributions can include lab-scale experimentation, underground research laboratories, observation of natural analogues, physics- and data-driven modelling and code development.
Furthermore, the session invites contributions addressing regulatory challenges, public outreach programs, lessons learned from national and international DGR projects, the need for transparent communication to ensure public confidence, and the relevance of geoscientific fundamentals in ensuring the safety of nuclear waste disposal.