Study on a Passive Method for Solving Thermal Stratification of Spent Fuel Pools

Abstract

The external power supply of Fukushima nuclear power plant was lost by the Great East Japan earthquake, which might have resulted in shortage of water in the spent fuel pool. Many researchers are developing cooling system of spent fuel pool (SFP) by loop heat pipe without power supply. However, thermal stratification in SFP was not considered to predict the cooling performance. The purpose of this study is to develop the solving system for thermal stratification without power supply by injecting air to SFP. Simulated test using thermosensitive self-operated valve was done. The flow visualization test and the solving test for thermal stratification have been done by using three kinds of air injection structure. The following conclusions are obtained. ①Air injection method can solve the thermal stratification. ②Using the thermosensitive self-operated valve, the air can be injected without power supply. ③Elbow type was suitable structure as air injection structure.