Fracture network prediction and rock suitability evaluation for spent nuclear fuel disposal
The knowledge of fracture network properties in crystalline rock is essential for the safety assessment and risk management of the final disposal of residual waste products from nuclear facilities in Sweden, hundreds of thousands of years into the future including the next glacial cycle.
Details
- Period: 2024-01-01 – 2027-09-30
- Budget: 5,000,000 SEK
- Funder: SSM
- Type of funding: Project Grant
Description
This is due to the critical role of fracture networks in safety-relevant processes in the host rock, ranging from the coseismic failure of waste canisters to the leakage of radionuclides into the geosphere. Relevant major technical barriers confronted by the Swedish KBS-3 repository concept lie at (i) realistically predicting the fracture network distribution in the repository site based on limited measurements, (ii) effectively avoiding highly conductive/deformable fractures that are detrimental to the repository performance when placing deposition holes, (iii) prospectively estimating the available rock volume for safe disposal along planned deposition tunnels, and (iv) quantitatively assessing the safety and optimality of a designed repository layout. Targeting at these core challenges, this project will deliver an effective and robust operational methodology that can support the regulatory review of repository design, safety assessment, and risk management of the KBS-3 repository in Sweden. The methodology developed will be tested extensively through relevant case studies based on the site characterisation data of e.g. the Forsmark site in Sweden and the Onkalo site in Finland. This project will be implemented via a close, international collaboration of two academic institutions including Uppsala University (Sweden) and Lawrence Berkeley National Laboratory (USA) as well as an industrial company, Clearwater Hardrock Consulting (USA). In addition, the project will be conducted within the DECOVALEX (DEvelopment of COupled models and their VALidation against EXperiments) framework, where about ten research teams of different institutions will compare their models with each other and against experimental observations, aiming to advance our predictive understanding of coupled thermo-hydro-mechanical-chemical (THMC) processes in geological media with application to spent nuclear fuel disposal in crystalline rock.