An integrated simulation framework for the performance assessment of radioactive waste repositories

Highlights: ► Integrated framework for a performance assessment of radioactive waste repositories. ► Use of Monte Carlo simulation for radionuclide migration at the repository scale. ► Numerical deterministic code for radionuclide migration at the geosphere scale. ► Application to a realistic case study. ► Advantage: modularity, i.e., interchangeability and interconnection. - Abstract: We present an integrated framework for a process-driven performance assessment of radioactive waste repositories. Key features of the proposed modeling strategy include: (1) the use of Monte Carlo-based simulation to model radionuclides migration at the repository scale, which allows simple management of realistic scenarios and (2) the adoption of a numerical code to provide realistic descriptions of the dynamics of radionuclide transport in natural groundwater bodies at the geosphere scale, from the release location to possible human intake occurrence. While repository-scale simulations are performed by the in-house code MASCOT, the subsequent groundwater flow and transport fields are depicted by means of the widely known and extensively used numerical codes MODFLOW and MT3DMS. An application to a realistic case study is presented to show the feasibility of the approach.