Multi-scale groundwater flow modeling during temperate climate conditions for the safety assessment of the proposed high-level nuclear waste repository site at Forsmark, SwedenModélisation multi-échelle des écoulements souterrains sous conditions climatiques tempérés dans le cadre de l’évaluation de la sécurité du site de stockage de déchets nucléaires de haut niveau propose à Forsmark en SuèdeModelado del flujo de agua subterránea multi-escala en condiciones de clima templado para la evaluación de seguridad del sitio propuesto como repositorio de residuos nucleares de alta actividad en Forsmark, Suecia瑞典福什马克所选高强度核废料储藏地安全评价中温带气候条件下多尺度地下水流模拟Modelação de fluxo multi-escala de águas subterrâneas durante condições climáticas temperadas para avaliação da segurança do proposto depósito de resíduos nucleares de alta atividade em Forsmark, Suécia

Forsmark in Sweden has been proposed as the site of a geological repository for spent high-level nuclear fuel, to be located at a depth of approximately 470 m in fractured crystalline rock. The safety assessment for the repository has required a multi-disciplinary approach to evaluate the impact of hydrogeological and hydrogeochemical conditions close to the repository and in a wider regional context. Assessing the consequences of potential radionuclide releases requires quantitative site-specific information concerning the details of groundwater flow on the scale of individual waste canister locations (1–10 m) as well as details of groundwater flow and composition on the scale of groundwater pathways between the facility and the surface (500 m to 5 km). The purpose of this article is to provide an illustration of multi-scale modeling techniques and the results obtained when combining aspects of local-scale flows in fractures around a potential contaminant source with regional-scale groundwater flow and transport subject to natural evolution of the system. The approach set out is novel, as it incorporates both different scales of model and different levels of detail, combining discrete fracture network and equivalent continuous porous medium representations of fractured bedrock.