Development and Qualification of a Smeared Fracture Modelling Approach for Transfers in Fractured Media

International audienceModelling transfers in fractured media remains a challenging task for nuclear waste storage. In this context, flow velocities around a repository are assumed very small which makes matrix diffusion to play a major role in strongly retarding mass transfers. The development and qualification of a novel smeared fracture approach adapted to these conditions is presented. Flow and transport are solved using a Mixed Hybrid Finite Element method, limited here to 2D problems for the sake of simplicity. The geometry of major fractures and matrix blocks is accounted for without handling a huge dedicated meshing. The precision of the method is studied for various test cases, mesh sizes and transport regimes. It is shown that the smeared fracture approach is accurate while limiting computational costs for transfers at low velocity typical of post closure conditions