Probabilistic Safety Analysis Of Cold Weather Risk In L Nuclear Power Plant

In the field of nuclear power, probabilistic safety assessment method has been widely used in many fields, such as the design, operation and maintenance of power plant. Through the analysis of probability and safety of nuclear power plant, it can find the weak in design and operation, so as to take effective measures to ensure nuclear safety, which makes the probability safety analysis method in the nuclear power plant safety management gradually improve.L nuclear power plant is replica design of LingAo Phase ?. Compared with the LingAo Phase II site, it has a relatively cold winter. Although L nuclear power plants located in the northeast region where has low ambient temperature in winter, the operating temperature of the internal power station equipment is guaranteed by heating systems when the off-site power is on. Therefore, the loss of offsite power (LOOP) only be considered when analyzing.In this paper, the loss of offsite power supply events are further classified and the impacts of the two events on the safety of nuclear power plants are discussed.In this paper, the description of the phenomenon of the loss of offsite power accident in the cold weather of L power station is described and the requirements of the safety function and the response mode of the accident are studied. Event tree method is used to analyze the time series and the sequence of events and the corresponding mathematical model are introduced. Fault tree analysis method is used to analyze the failure of safety function and the relevant hypotheses are made in the process of determining the fault tree.Finally through quantitative analysis, we conclude that cold weather conditions of power plants has certain effect to the reactor core damage, but in the acceptable range and improving the reliability of auxiliary feed water and high pressure safety injection recirculation system is an effective way to reduce the probability of core damage and recommending that adding the manual isolation valve and check valve is an effective way to improve the reliability of the auxiliary water pump ventilation system.