Publications Details

Reduced-order THMC coupled simulation of nuclear waste disposal in shale

Chang, Kyung W.; LaForce, Tara; Nole, Michael A.; Stein, Emily S.

Thermal and hydrological behaviors of multiphase pore fluids in the presence of heat cause the near-field thermo-hydro-mechanicalchemical (THMC) coupled processes that can influence performance of geologic radioactive waste repositories. This hydro-thermal impacts may perturb the geomechanical stability of the disturbed rock zone (DRZ) surrounding the drifts in a shale-hosted deep geologic repository, which links heat/fluid flow and chemical/reactive transport between the engineered barrier system (EBS) and the host rock. This work focuses on integrating the effects of a near-field geomechanical process driven by buffer swelling into TH simulations to reduce dimensionality and improve computational efficiency. This geomechanical process can reduce the DRZ permeability, potentially influencing the rate of radionuclide transport and exchange with corrosive species in host rock groundwater that could accelerate waste package degradation. The sensitivity test with variation in host rock permeability indicates that less permeable shale retards re-saturation of the buffer, such that slower increase of swelling pressure delays reduction of DRZ permeability.