The BASE (German Federal Office for the Safety of Nuclear Waste Management) research project Evaluation of Retrieval Concepts (BeRK) project addresses the following research questions: how could different retrievability measures and specific retrieval concepts be comparatively evaluated? How can measures for implementing and optimising retrievability be assessed in terms of their safety significance? How can trade-offs be reconstructed?

For 25 years, the rock laboratory at Mont Terri (Switzerland) has been playing an important role in the feasibility and safety studies of deep geologic radioactive waste repositories in clay formations. For the last 12 years, the Bitumen–Nitrate–Clay experiment has been running in situ experiments in this lab. This experiment addresses questions concerning the effect of biogeochemical perturbations of the clay by nitrate from radioactive waste on the migration of redox-sensitive radionuclides.

This workshop aims to bring together experts in both fundamental research on radionuclide chemistry and mobility and its applications to repository safety. It intends to facilitate knowledge exchange between the two fields, promoting more coordinated and goal-oriented safety research.

In this workshop we want to link discussions regarding extended interim storage to the long-term safety of geological repositories. Aspects of the discussion could be as follows: could the embrittlement of the fuel cladding lead to difficulties in transportation and conditioning? Could the decreasing thermal energy of the inventory lead to temperatures that negatively affect safety-relevant aspects? We are looking forward to a multi-faceted discussion that may go well beyond the given examples.

Up to now, only little research has been done on the question of when a scenario is covered by calculation cases. The outcome of the EMS (Entwicklung einer Methode zur szenariengestützten Identifizierung von Berechnungsmodellen) project is intended to support the Federal Office for the Safety of Nuclear Waste Management (BASE) within the framework of supervision and approval in the evaluation process of whether scenarios have been sufficiently covered by calculation cases.