Effects of Variable Saturation on the Thermal Analysis of the Engineered Barrier System for a Nuclear Waste Repository

The effects of the resaturation process occurring in the buffer on the analysis of temperature distribution in the engineered barrier system of a nuclear waste repository were assessed. The assessment was performed using the TOUGH2 computer code, which analyzes the multidimensional fluid and heat flows of the multiphase, multicomponent fluid mixture in an unsaturated medium. The hydraulic and thermal properties of the buffer, backfill, and near-field rock were measured and were used as input parameters for the analysis. If the resaturation process is considered in the thermal analysis, the disposal density of nuclear waste can be increased up to 30% under the given thermal constraint and site condition. The hydrostatic pressure in the near-field rock will not have an important impact on the resaturation process.