CFD simulation of the thermal-hydraulic characteristics within spent fuel storage pool

The spent fuel rods unloaded from reactor core have massive decay heat and are temporarily stored in the spent fuel pool. It is important for the safety operation of nuclear power plant to determine whether it has proper capability to remove the decay heat. The objective of the present study is to research the residual heat removal ability of spent fuel pool under various unloaded scenarios and influences of various arrangements of inlet pipe. CFD methodology was applied to develop a tool for spent fuel pool thermal hydraulic analysis. The heat transfer at the interface air/liquid was modeled by using effective heat transfer coefficient, which was attained by considering the heat transfer including the natural convection of the air and the vapor of hot water. Results show that the arrangement of the inlet pipe located at the bottom of the spent fuel storage pool, considering the capacity of removing decay heat, is superior to all other arrangements. Both under normal conditions and even more severe scenarios, cooling system can remove the remaining residual heat and the peak temperature locates at the top region of spent fuel storage rack. There exit strong natural circulation, which enhances the flow and heat transfer process in the storage pool. The present studies are of great significance and can provide valuable references for the design and optimization of spent fuel storage pool.