Faire avancer la sûreté nucléaire

La Recherchev2


Fully coupled modeling of radionuclide migration in a clayey rock disturbed by alkaline plume



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D. Pellegrini, L. de Windt, J. van der Lee Workshop on modeling of coupled transport reaction processes. TRePRo 2002 Rapport IRSN-DES/485


The disposal of radioactive wastes in clayey formations may require the use of large amounts of concrete and cement as a barrier to minimize corrosion of steel containers and radionuclide migration and for supporting drifts and disposal vaults. In this context, reactive transport modeling of the interactions between cement or concrete and the argillaceous host rock aims at estimating the evolution in time of the containment properties of the multi-barriers system.
The objectives of the paper are to demonstrate that integrating radionuclides migration in the modeling of strongly coupled geochemical processes of cement-claystone interactions is feasible and that it represents an efficient way to assess the sensistivity and modification of the classical Kd and solubility parameters with respect to the chemical evolutions. Two types of modeling are considered in the paper: i): calculation of intrinsic solubility limits and Kd values backing up on the results of modeling of cement/claystone interactions (radionuclides are assumed to be present over the whole domain at any time whatever the scenario), ii) full mechanistic modeling which explicitely introduces radionuclides in the calculation with ad hoc assumptions on radionuclide inventory, canister failure, migration pathway, etc.