The Swiss deep geological repository – A century project

Switzerland is planning a deep geological repository to safely dispose of all radioactive waste. After a multi‐stage site selection process involving nationwide screening, geological investigations and extensive deep drilling, Nördlich Lägern was identified as the safest location due to its tectonic stability and the favourable properties of Opalinus Clay, the host rock offering long‐term containment. The general licence application was submitted in 2024. A provisional repository concept was developed, comprising a surface facility and an underground facility accessed by three shafts. At 800–900 m depth, radioactive waste will be emplaced in drifts or caverns. Long‐term safety is ensured through a multi‐barrier system combining engineered and natural barriers. Construction is planned in phases, with emplacement starting in 2050. Extensive geotechnical investigations confirm the anisotropic yet predictable mechanical behaviour of the host rock. Tunnel boring machine (TBM) tunnelling and shaft sinking require careful design to address squeezing ground, lining overstressing and potential water inflow in the shaft in the layers overlying Opalinus Clay. The project will evolve further based on site‐specific data and future operational requirements to realise a safe, feasible and adaptable repository.