COBRA-SFS dry cask modeling sensitivities in high-capacity canisters

Material temperature predictions for dry-cask storage are dependent to varying degrees on user specified model assumptions. To understand the importance of various areas of the dry-cask thermal model, the temperature prediction sensitivity of these parameters has been evaluated. Thermal modeling assumptions are used to approximate cask geometry, fuel assembly design variations, physical properties of cask materials and fill-gas, and environmental conditions of the storage site. The result of this sensitivity study identifies which of these areas will produce the largest reduction in temperature prediction uncertainty with additional testing and measurements of actual cask systems. The scope of this work is to understand the COBRA-SFS modeling parameter sensitivities for the vertical high-capacity canister system. In general, the results show that cask material temperatures depend most on radiative and convective heat transport. The accuracy of the COBRA-SFS model for high-capacity vertical canisters hinges upon accurately modeling channel geometry in the canister and cask annulas.