Temperature Prediction Of A TN-32 Cask With Non-Concentric Basket Subjected To Vacuum Drying

In this work, geometrically-accurate two-dimensional computational fluid dynamic models of a used nuclear fuel cask that can contain up to 32 pressurized water reactor (PWR) fuel assemblies are constructed. These models are similar to the TN-32 cask currently employed in the ongoing high-burnup (HBU) Spent Fuel Data Project lead by the Electric Power Research Institute (EPRI). These models are used to predict the peak cladding temperature (PCT) under vacuum drying conditions. In a typical TN-32 cask, the fuel basket is designed to be concentric inside the cask, leaving a constant 4.8-mm gap with the aluminum rails. Previous work by the authors showed that this gap accounts for a significant increase in the PCT. In this work, we will investigate the effect of the fuel basket leaning on one or two sides of the cask, closing the gap on those sides, and enlarging it on the opposite sides. Steady-state simulations that include the temperature-jump boundary conditions at the gas-solid interfaces to into account the rarefaction effect at low pressures will be performed for a range of dry helium pressures ranging from ~105 to 100 Pa in all the configurations (concentric, single-side leaning, and double-side leaning). The PCT will be reported for different pressures. The maximum allowable heat generation that brings the cladding temperatures to the radial hydride formation limit of 400°C will be also reported.