The future repository for high-level radioactive waste must fulfil a number of safety requirements to ensure that it does not pose a risk to humans and the environment in the long term. During the site selection procedure, it will repeatedly be necessary to decide whether a selected area or a possible site can fulfil these requirements in order to be considered in the further procedure as a site with the best possible safety for the final disposal of high-level radioactive waste.

These decisions are to be made on the basis of preliminary safety studies. For example, the preliminary safety studies must show - among many other aspects - that possible exposures due to discharges of radionuclides from the stored radioactive waste would be negligible compared to natural radiation exposure.

Together with the exclusion criteria, minimum requirements and consideration criteria, preliminary safety investigations serve to identify the site that offers the prospect of the best possible safety in the long term.

The main focus will be on the comparability of the findings and results, since on the one hand there will be significant differences in the safety concepts for specific sites and on the other hand the quality of the available data and the associated uncertainties will differ.

The safety requirements for a repository and the requirements for the preliminary safety investigations are specified in legal ordinances pursuant to Sections 26 and 27 of the StandAG. The preliminary safety investigations are carried out in all three phases of the site selection procedure and become more detailed with each phase.