Phenomenological Description of the Evolution of a Geological Repository for Radioactive Waste in Opalinus Clay.
Nagra (2024): Phenomenological Description of the Evolution of a Geological Repository for Radioactive Waste in Opalinus Clay. Nagra Arbeitsbericht NAB 24-20 Rev. 1.
The present report outlines the expected evolution of a combined repository for high-level, low- and intermediate-level, and alpha-toxic radioactive waste in the Nördlich Lägern siting region, Switzerland. It provides a high-level description of the expected evolution and behaviour of the repository system, its components, and its surrounding environment over extended periods, as well as noting the main uncertainties.
Key elements of this description include the waste inventory, the location and layout of the deep geological repository the engineered repository components, the long-term safety-related impact of construction, operation and closure of the repository, the evolution of underground openings prior to backfilling, and the long-term interactions between components, including repository-induced effects on the host rock. The description also accounts for geological and climatic processes over extended timescales, such as erosion, uplift and fault activation.
The narrative of the expected evolution of the repository presented in the following sections is based on current scientific understanding, including uncertainty, documented in the assessment basis reports and brought together within the present report.
This comprehensive description of the expected evolution provides a robust foundation for assessing post-closure safety of a combined repository for radioactive waste in the siting region of Nördlich Lägern that is based on a provisional design to ensure the protection of both human health and the environment for millennia to come.
Supplementary Volume:
Nagra (2024): Phenomenological Description of the Evolution of a Geological Repository for Radioactive Waste in Opalinus Clay: Handling of FEPs in the Safety Assessment. Nagra Arbeitsbericht NAB 24-20 Suppl. Vol. Rev. 1
The present report supplements the phenomenological description of the evolution of the combined repository (Nagra 2024a) by developing a FEP database and auditing the phenomena included in the safety assessment against Nagra’s FEP database.