Reconstructing the past as a glimpse into a (potential) future: The impact of glacigenic processes on the long-term safety of radioactive waste repositories

Long-term safety assessments for a deep geological repository for highly radioactive waste require evaluating potential future geological and climatic developments over the next one million years. Therefore, the impact of potential future cold stages and glaciations on the geological barrier needs to be considered. The glaciation of a repository site is likely to have the largest effect; however, repository sites located outside the maximum ice-sheet extent may also be affected. Relevant processes with potentially large impacts that can reach repository-relevant depths include glacigenic erosion, ice-load induced deformation, and permafrost formation. A sound understanding of the processes during past glaciations is key to assessing the potential impact of future glaciations, which may serve as analogues. We present examples from current case studies that use reconstructions and numerical modelling of Pleistocene processes to support long-term safety assessments. The first case study focuses on the incision of Pleistocene tunnel valleys in northern Germany. Based on zones of similar depth, the potential for future subglacial erosion is assessed (Breuer et al. 2023). The distribution and orientation of tunnel valleys are compared to the regional structural framework to understand the geological control on subglacial incision (Lang et al. 2025). The second case study presents a numerical model of the response of salt structures to ice-sheet loading (Lang & Hampel 2023), offering new insights into the controlling factors of ice-salt interactions.

References:

Breuer et al. (2023) DOI: https://doi.org/10.5194/egqsj-72-113-2023

Lang & Hampel (2023) DOI: https://doi.org/10.1007/s00531-023-02295-5

Lang et al. (2025) DOI: https://doi.org/10.1111/bor.12694