Study of Station Blackout Caused Severe Accident Process in Daya Bay Nuclear Power Station

Based on the severe accident calculation results of Daya Bay Nuclear Power Station,this paper analyzes a certain of accident sequence and the mitigating measures of severe accident.The results show that the top of core will be uncovered about 1~2 hours later,and the reactor pressure vessel will fail after 5~7 hours.The containment will fail after about 100 hours.The cavity basement can be penetrated about 5.5m after 8.7 days.The results also show that the pit flooding can prevent the melt-through of the basement and reduce hydrogen mass from interaction of molten corium with concrete.