Thermal Analysis of Spent Fuel Transportation Cask

Spent fuel transportation casks are required to meet among others, the regulatory thermal test conditions in order to demonstrate their ability to withstand specified accidental fire conditions during transport. This paper describes the transient thermal analysis performed with the above intention for a transportation cask that has not undergone drop test and is not damaged. The original dimensions are used for computations. The analysis was carried out using a heat conduction code employing the Finite Element Method (FEM). At the outset, a benchmark exercise was carried out with the present code to ascertain its capability to carry out calculations involving phase change. The benchmarking was done against the solution given by commercial CFD code STAR CD. After assessing the suitability of the FEM code, it was employed for thermal analysis of the transportation cask. The computation covers normal transport condition, half an hour fire test at 800°C and also the post fire cool down period. The objective of the analysis was to determine the maximum outer surface temperature for normal transport conditions and to assess the extent of melting of lead during fire and post fire period.