The effect of spatial variability on uranium diffusion in Opalinus Clay over a million years was assessed by 2D reactive transport simulations. Different rock types and porosity impacted results, with variability's influence growing with longer correlation lengths of geostatistical simulations (up to 12.9 %). This highlights that 1D models may underestimate uncertainty in long-term radionuclide transport at repository sites, and spatial variability must be considered.

The safe disposal of nuclear waste requires consideration of future developments in nature on the repository, like for instance glacifications. We show an approach by using a sophisticated database for a systematic consideration of such developments and their possible interactions.

This study explores how rock salt reacts to hydrogen, aiming to support safe underground storage of renewable energy. Lab tests on samples from a potential salt cavern-type site in Spain showed that hydrogen caused no major changes to the rock. Minor effects were limited and did not impact overall stability. These findings help confirm that storing hydrogen in salt formations is a safe and reliable option for future energy systems.

The prevailing view in the scientific community is that large amounts of carbon dioxide (CO₂) from the atmosphere and highly radioactive waste must be disposed of safely. In that regard, studies on natural processes that extend over thousands of years help to assess the long-term behaviour of deep geological repositories. From a purely scientific point of view, CO₂ storage and final disposal of highly radioactive waste are feasible.