Natural Heat Transfer Performance of Helium Filled Spent Fuel Multi Purpose Container Calculated for Different Initial Pressures

The simple model of helium filled Holtec’s Multi Purpose Container (MPC) for 37 spent fuel assemblies was developed and the calculation was performed using the Ansys Fluent code in steady state. The flow and temperature distribution within the MPC was calculated for different initial helium pressures, and for limiting cask heat loading found in the NPP Krsko SFDS (Spent Fuel Dry Storage) campaign number 1. The determined relationship between helium top to bottom temperature increase and helium pressure decrease can be used as a measure of cask leakage. In addition, lateral temperature distribution in the top MPC plenum, influenced partially by different spent fuel assembly loading, should be checked as a cause for temperature variation at the MPC external top surface, where RTD (Resistance Temperature Detector) detectors are installed.