Sensitivity analysis for numerical modeling of a generic repository for nuclear waste in bedded salt

Numerical models of a generic repository for nuclear waste were created to analyze the long-term barrier integrity of bedded salt formations. This study focuses on sensitivity analysis and validation for numerical simulation by using 2D models. Under consideration of thermal loading caused by the disposal of heat generating nuclear waste, thermal and thermomechanical coupled calculations were performed using FEM code JIFE (Faust et al. 2016). Thermal analyses were conducted to investigate the influence of mesh density on the temperature results in both near and far field of disposal area. Thermomechanical coupled calculations were carried out to evaluate boundary influence of different model dimension on the results of temperature and vertical displacement. Furthermore, since the overburden are assumed to be elastic, variation of Young’s modulus shows sensitivity of overburden stiffness in thermomechanical coupled calculations of the generic model for bedded salt. The calculated stress and deformation were compared to investigate the influence of overburden stiffness on the results of geomechanical assessment of the salt barrier integrity. The observation of this study gives a better understanding of how to establish a 2D or 3D model in bedded salt formation for barrier integrity analysis.