Modélisation de la migration de soluté sorbant et non-sorbant dans une géométrie de fracture réelle à l'aide d'un automate cellulaire de type gaz sur réseau
A. Genty (IRSN), V. Pot (INRA) - Computional Methods in Water ressources, Chapel Hill USA- 13-17 juin 2004
Fractures are features that may be encountered in a potential host rock for high level nuclear waste disposal. They may appear as potential pathways for radionuclides transport. Hydrodynamic properties of the transport inside these systems must then be characterized. Miscible non-sorbing tracer displacements were performed on 2-D real fracture geometry with lattice-gas cellular automaton (LGA). LGA was shown to easily handle the complex geometry of such a fracture. The numerical breakthrough curves obtained were inverted by mean of the CDE and the MIM transport models. Two main conclusions were drawn : (1) at lengh scale of the study, transport in our fracture geometry was more accurately interpreted in terms of the MIM model rather than in terms of the classical CDE model; (2) retardation factor alone was not sufficient to account for the effect of sorption on transport : hydrodynamic dispertion coefficient value had to be increased in addition.