Nagra has submitted a general licence application (RBG) for a deep geological repository for low- and intermediate-level waste (L/ILW), alpha-toxic waste (ATW) and high-level waste (HLW) in the Opalinus Clay in Nördlich Lägern, Switzerland. The application is supported by a large number of technical reports which have been made available on a dedicated digital platform, allowing anyone interested to study the supporting safety case. Quintessa has worked for several years to provide post-closure safety assessment support Nagra’s application.
Quintessa’s work has contributed to the latest iteration of assessments supporting selection and demonstrating safety for a repository at Nördlich Lägern for the RBG. It has included:
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support to the source-term modelling code STMAN, the geosphere retention and radionuclide transport modelling code PICNIC-TD, and the biosphere modelling code SwiBAC (referenced in NTB 24-10);
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treatment of C-14 in the post-closure safety assessment (NAB 24-07), including a supporting report on biosphere modelling for C-14 (NAB 23-25);
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biosphere modelling (NAB 24-06) and a supporting report on development of an updated biosphere sorption database (NAB 23-14); and
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assessment of hypothetical scenarios of repository excavation by erosive processes (deep glacial erosion and hillslope erosion) in the very far future (NAB 24-08).