Research On Methods Of Passive Decay Heat Removal Of Nuclear Power Plant

The research of nuclear power plant passive safety is a crucial task to ensure the safe use and the further development of nuclear energy. The aspect of passive safety is studied in this thesis. Some next generation reactors in the world and their passive decay heat removal system designs are analyzed and summarized. The RELAP5 code is a great thermal-hydraulic transient analysis code at present and it is used as the tool of studying passive decay heat removal system for AP-1000 in this thesis. At the same time, a new passive decay heat removal system was put forward.In the thesis, the RELAP5 code is used for simulating and calculating the passive decay heat removal system of the third generation advanced power water reactor AP-1000 which was recently introduced into our country. The calculative results indicate that in the event of a loss of offsite power and all other reliable power, the passive decay heat removal system and the passive containment cooling system for AP-1000 can provide infinite capacity for decay heat removal without the manipulator taking any action. Meanwhile, a new passive decay heat removal system is put forward. According to the comparative character of the two systems, the calculative results are qualitatively analyzed compared with the results of passive decay heat removal system for AP-1000. The results show that however the new passive decay heat removal system could enhance the inherent security of the reactor compared with passive decay heat removal system for AP-1000, it would increase load for passive containment cooling system.Analyze these results, we come to the conclusion in the thesis that these two systems have their own advantages, however, in the event of a loss of offsite power and all other reliable power, they both can achieve the function of exporting the core decay heat and ensure the reactor's safety.