According to studies of the Federal Institute for Geosciences and Natural Resources (BGR), there are clay stone formations in Northern and Southern Germany that may be suitable to host a repository for heat-generating radioactive waste. Clay stones have low permeabilities and are thus used in industrial applications; e.g. to seal conventional waste disposal sites or disposal sites for chemical-toxic waste. In addition to their low permeability to fluids, clay stones have good retention properties for radionuclides, which qualifies them as host rocks for repositories. Within the scope of project ANSICHT, which was jointly carried out by DBE TECHNOLOGY GmbH, BGR, and Gesellschaft für Reaktorsicherheit (GRS) gGmbH, two generic geologic site models were used to develop a first draft of a methodology to demonstrate the safety of a HLW repository in clay stone in Germany, taking into account the regulatory requirements. This method has the advantage that it links geologic boundary conditions with the development of a repository concept, especially the development of an emplacement and sealing concept and of a corresponding demonstration of the barrier integrity, and with an analysis of the expected and alternative repository developments. The results of project ANSICHT are fundamental for a safety-related and evidence-based design of repository components as well as for the construction, operation, and closure of a repository in clay formations. They, thus, form a useful tool in the pending search for a HLW repository site, especially when it comes to providing a basis for comparing safety analyses of different sites. The documents related to this project will soon be available for download on our website in the media section under FuE-Berichte.