| Summary: | 碩士 === 國立清華大學 === 核子工程與科學研究所 === 101 === This research focuses on the analysis of station blackout (SBO) accident in Maanshan nuclear power station and the mitigation capability of SBO response strategy so called the ultimate response guideline (URG) by using TRACE code. Maanshan NPS is a Westinghouse 3-loops PWR power station. In year 2001, a real SBO accident happened in unit 1 of Maanshan NPS. This research uses the input model that has verified with plant startup test to simulate the SBO accident happened in 2001, and then analyze hypothetical SBO accident with URG and other sensitivity studies by using this verified model.
Main action of URG including steam generator (SG) and reactor coolant system (RCS) depressurization, and SG injection by using alternate equipment if onsite regular injection systems aren’t available. The simulation results of SBO accident with URG show that, by executing the URG during SBO can keep the nuclear fuels covered with water and prevent fuel cladding from damage.
Considering the SG injection capability and preparation time may be an uncertainty during SBO, the research evaluates the minimum required injection flow rate to be 40 gpm/SG and the preparation time no more than 3 hours in order to keeps the fuels covered with water. Furthermore, if a 21 gpm/pump leakage rate of reactor coolant pump (RCP) seal LOCA happens during SBO with URG executed, simulation result shows that reactor water level will drop to TAF in 70 hours. Therefore, RCS alternate injection and quick restoration of onsite AC power should be considered to maintain the reactor water level if RCP seal LOCA happens.
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