Geological Properties of the Jura Ost, Nördlich Lägern and Zürich Nordost Siting Regions for Safety Assessment
Nagra (2024): Geological Properties of the Jura Ost, Nördlich Lägern and Zürich Nordost Siting Regions for Safety Assessment. Nagra Arbeitsbericht NAB 24-10 Rev. 1.
The Sectoral Plan for Deep Geological Repositories (SGT) has defined the safety-oriented site selection process since 2008. In the third and final stage of the site selection process, the database for the geological site characterisation was improved significantly in the three siting regions Jura Ost (JO), Nördlich Lägern (NL) and Zürich Nordost (ZNO).
Compared to SGT Stage 2, core observations, geophysical logging, and in-situ and laboratory testing were expanded significantly with nine new exploration boreholes (TBO). The regional 3D-seismic measurements in the siting regions also represent an important new dataset. Overall, the combined exploration efforts with 3D seismics and deep boreholes ensures a comparable data basis for all the siting regions.
This report focuses on the spatial geometry of geological layers and key rock properties relevant for transport and assessment of barrier integrity. These properties are evaluated in mineralogical and petrophysical, hydrogeological and geomechanical chapters. The derivation of representative parameter ranges for these key properties is based on a data-driven abstraction and subdivision of the geological units. The observations and measurements of the TBO are compiled and interpreted considering spatial variability, scaling aspects and uncertainties. Representative parameter value ranges are specified for each of the three siting regions.
The report complements the geosynthesis (Nagra 2024e) with a comprehensive site-specific geological description and parametrisation, which serve as a basis for the repository performance assessment (Nagra 2024g) and radiological consequence analysis (Nagra 2024i).