Temperatures of Interest for the TN-32 Cask during Storage of High Burnup Fuel

The TN-32 cask is licensed to store 32 pressurized water reactor used fuel assemblies, with a maximum allowable decay heat load of 32.6 kW. In this work, a three-dimensional (3D) model of the TN-32 cask has been constructed for computer simulation by using the ANSYS finite element code. Analyses have been conducted to calculate the temperatures of interest for the key components in the TN-32 cask: high burnup fuel cladding, metal Helicoflex seals, and top and radial neutron shields. The various fill-gas conditions inside the cask are (1) vacuum drying before the cask is pressurized with helium; (2) dry storage under normal conditions with helium backfill; and (3) dry storage with air backfill, which simulates leakage of helium gas from the cask. Future study will examine the effects of mixed-zone loading of used fuel assemblies with different burnups on the peak cladding temperatures. The results of these thermal analyses should provide insights into the temperatures of interest of the key components in the TN-32 cask and help support the U.S. Department of Energy High Burnup Dry Storage Cask Research and Development Project.