Sensitivity analysis of COBRA-SFS for dry storage of spent fuel

The storage in the spent fuel pool for spent fuels of the domestic power plant is expected to be saturated from 2024. As a practical alternative to solve this problem, an intermediate storage through the dry storage of spent fuel is considered. Studies about spent fuel for the dry storage are performing for the low burnup fuels, which accounts for 80% of the domestic spent fuels. The degradation of the spent fuel during the dry storage depends on the temperature profile. Thus the temperature profile is suggested as the first item on the gap analysis report. The sensitivity analysis with COBRA-SFS, a thermal hydraulic analysis code for spent fuel storage and transportation casks is performed to decide the priority of the model development and experiment variables. The properties of a backfill gas such as helium cause a difference of about 3%. In particular, it can reduce error by providing precise properties for thermal conductivity, enthalpy, and specific volume. The sensitivity analysis about the energy exchange models, which is expected to cause major deviation is currently in progress