Abstract
The nuclear industry raises doubts about the safety of spent fuel pools in extreme events after the Fukushima Daiichi nuclear disaster. In this research,the prediction of water level and temperature under LOCA(loss of cooling accident) are simulated by using CFD code.Assuming that LOCA occurs after 7 days of post-shutdown with full core unload in spent fuel pool.For the purpose of making the background similar to the Fukushima unit 4 spent fuel pool issues, the model is established without any cooling ability.The nuclear power plant currently in operation including boiling water reactor and pressurized water reactor.Therefore,by choosing the Kuosheng and Maanshan power plants to cover all types of nuclear power plants.The entire accident model is established with three phases separately：The first phase is the water reaches saturation temperature with transient,the second phase is the water level decrease due to boiling and the third phase is the rate of temperture increases rapidly as the spent fuel uncovers with steady state.The second phase of the process will be replaced by energy conservation estimates where CFD is only caculated for single-phase situations in this research.Set the fuel rack or not, various heat loss and the impact of different rack design will be considered in the first phase.As long as the fuel can be covered by water during the accident,it will be able to ensure that meltdown will not happent and lead to more serious consequences.Taipower Company adopted the NEI 06-12 : The system should be capable of being deployed external SFP makeup from the time loss of cooling ability within 2 hours.Therefore, the calculation results under the decay heat settings and background conditions in this research fully proved that Taiwan Power Company is still able to cope with the safety requirements of the spent fuel pool under LOCA when it encounters an extreme events.