Thermal-geological data for the safety analyses of repository systems in sedimentary host rocks of Germany

Understanding the temperature field is essential for conducting safety analyses during site selection for a repository of heat-generating radioactive waste in Germany. The initial temperature distribution in the respective host rock determines the repository design. This information is also important for analysing possible future developments of repository systems regarding the safe confinement of radioactive nuclides. In the BGE-funded project ThermoBase, BGR and GFZ are collaborating to characterize the subsurface thermal conditions in regions with sedimentary host rocks, such as rock salt and claystone.

BGR carries out stochastic analyses of the influence of parameter variations on the temperature in the host rock and the overburden. Numerical repository system models of varying complexity are used for the safety-related assessment of the influence of the variance of thermal rock properties and boundary conditions on the temperature development in the final repository. First analyses provide insights into the effects of parameter variation on the thermal field.

GFZ is developing detailed 3D geological models for transient conductive temperature and heat flow simulations. New measurements of rock thermal properties are being conducted on core sections in the laboratory and derived from high-resolution geophysical logs. First results provide insights into the spatial variability of the thermal field and its implications for repository planning.