Three Dimensional Analysis of Combined Gas, Heat and Nuclide Transport in a Repository in Rock Salt Considering Coupled Thermo-Hydro-Geomechanical Processes

摘要

To study the coupled thermo-hydrologic-geomechanical processes and their influence on gas and nuclide transport in a two phase flow configuration in a porous medium, a coupling of the thermo-hydrodynamic code TOUGH2 and the thermo-mechanic code FLAC3D is described and applied to analyze three dimensional gas, heat and nuclide transport in a repository for heat generating nuclear waste in rock salt. According to stress dependent hydrological properties, like, porosity, permeability and capillary pressure, the influence of coupled processes on a two phase flow can be relevant. The present procedure can be applied to quantify safety margin related to hydro-fracturing and dilatancy due to fluid pressure build-up and to define bounding analyses, if the hydrological properties, such as porosity, permeability, and capillary pressure, depending on mean effective normal stress are used.