Radionuclide Migration in the Far-Field: The Use of Research Results in Safety Cases

Fundamental processes governing radionuclide migration in the geosphere were investigated in the FUNMIG project. Component 6 coordinated the linking of the scientific work performed in Components 1 to 5 to its use in performance assessment and monitored the improvements achieved within this project for individual safety cases. Boundary conditions for the near-field of a radioactive waste repository, in particular radionuclide fluxes and concentrations but also repository induced perturbations of the geosphere, were defined based on existing safety cases and on the outcome of the NF-PRO project . A catalogue providing concise information for each task performed in FUNMIG was compiled. It facilitates the retrieval of knowledge acquired within FUNMIG and was used to map these tasks to international lists of Features, Events and Processes for clay-rich, crystalline and salt host rocks. The subsequent evaluation revealed issues important for future safety cases, namely the mechanistic understanding, quantification and up-scaling of radionuclide diffusion in clay-rich host rocks and, for crystalline host rocks, the influence of colloids on radionuclide transport and the up-scaling of reactive transport modelling in fractured systems.