Model of final geological repository.

A deep underground repository for high-level radioactive waste, where the waste can be safely stored and protected from external influences for tens of thousands of years. A suitable location is a stable geological formation without tectonic faults, away from groundwater, without the risk of being affected by external influences such as earthquakes, floods or volcanic eruptions. The repository should be built at a depth of approximately one kilometer below the surface. The waste stabilised in a solid matrix, e.g. by vitrification, will be stored in corrosion-resistant metal containers covered with clay or bentonite, which will serve as an additional barrier against possible radionuclide leakage. As of 2023, only a few final repositories were in operation, with others in the planning stage or under construction.