Study of the TN24p dry cask cooling by heat pipes

Abstract

The management of spent fuel is an issue of great relevance for the future of nuclear energy. In some countries, such as Finland, the construction of a Deep Geological Storage for the long-term cooling, has already begun. In others, the construction of a Centralized Temporary Storage is still being managed, as in Spain, and on-site Dry Cask Storage must be implemented in each nuclear power plant.Several considerations must be taken into account to start building new storage facilities, such as the proper heat removal considering the environmental conditions, the burnup of the spent fuel and the long-term behaviour of the dry cask materials. In order to better evacuate heat, the use of heat pipes is proposed in this study to cool fuel assemblies inside the TN24p dry cask.The objective is to calculate, using CFD (Computational Fluid Dynamics) models, the heat that can be extracted from a TN24p cask with heat pipes and to perform a comparative analysis with respect to a base case without these devices. These data allow exploring the possibility of using the heat for additional applications and give us an idea of how much the temperature is reduced, increasing the temperature margin in the dry cask.The simulations of an eighth of the TN24p cask, carried out with the STAR-CCM+ code, are considered a good starting point to study sensitivity analyses. It was concluded that the determining factor is not the heat sink design but the heat pipe one, which leads to the modification of its equivalent conductivity.