Report on the long term safety of the final repository SMA at the Wellenberg site (Community of Wolfenschiessen, Canton Nidwalden)

This report was prepared as part of the documentation of the application for a general license for the proposed repository for low- and intermediate-level wastes at the Wellenberg site. The aim of the report is to document the deliberations performed for the safety assessment of the repository. A conservative approach is adopted in the safety assessment, in that not all of those features of the site which potentially increase the level of safety which can be demonstrated are considered and pessimistic assumptions are made in the event of uncertainties in scenarios, models and data. The safety assessment results indicate a sufficient degree of long-term safety. For the reference case, which is based on realistic-conservative assumptions, predicted radiation doses lie well below the regulatory dose limit of 0.1 mSv/a. For alternative model assumptions and alternative scenarios as well as for the wide range of parameter variations considered, the resulting radiation doses are also below the regulatory limits. However, for some cases the safety margins are smaller. The results of the safety assessment therefore lead to the conclusion that Wellenberg is a suitable site for submitting an application for the general license for the Wellenberg site and for continuing work to implement the L/ILW repository. (author) figs., tabs., refs