Safety analyses are an essential element in the site selection procedure for a repository for high-level radioactive waste, but also in licensing procedures for repositories in general. On the one hand, these concern repository operation, with the safety of normal operation in accordance with regulations and the handling of incidents. Long-term safety analyses, on the other hand, concern the demonstration of the safety performance of a repository system in the phase after closure over a regulatory period of 1 million years. In these analyses, possible future developments of the repository system must be considered and their impact on the safe containment of radionuclides in the repository must be evaluated. These long-term safety analyses concern:

• A scenario development, in which the conceivable developments of the repository system concerned are systematically derived, taking into account the probability of occurrence of the respective scenario.
• Integrity analyses demonstrating that the (geo)technical and geological barriers will not be inadmissibly impaired in their containment effectiveness by processes occurring in the future.
• Radiological consequence analyses that show that over the entire detection period, the radiological exposure for humans and the environment will remain below regulatory dose limits.

Since there are naturally considerable uncertainties about the development of the repository system due to the prognosis over extremely long periods of time, the systematic identification of uncertainties and their consequences for the long-term safety assessment of the respective repository system plays an important role.

In this context, so-called monitoring also plays a role. This means that during the operating phase, and possibly also with restrictions in the phase after closure of a repository, measurements are taken to check whether the assumptions on which the safety demonstrations were originally based (e.g. concerning the dynamics of heat generation of highly radioactive waste) are actually correct.

Poster or lecture topics on this very interdisciplinary, comprehensive and therefore exciting topic are also very welcome for the site selection days. We look forward to a lively participation in this regard as well.