Reliability Analysis Of Nuclear Power Plant Reactor Emergency Shutdown System Based On Dynamic Bayesian Network

At this stage,nuclear power technology is rapidly developing and popularizing.To ensure the safe and stable operation of nuclear power plants not only has considerable economic benefits,but also is extremely important for public safety.As a safety critical system,the reactor emergency shutdown system can control the relevant shutdown operation according to the operating parameters of nuclear power plant,so it is necessary to study its reliability.Reactor emergency shutdown system is a multi redundant system with dynamic operation and complex failure mechanism.There are obvious dynamic characteristics in the mission cycle of the system.At present,the dynamic and timing characteristics of the scram system are seldom considered in the analysis method,and a mature analysis scheme has not been formed,Secondly,the traditional reliability analysis method does not consider the complex failure mechanism of the system and the fuzzy uncertainty in the failure rate of components.It is often insufficient in the description of the failure mechanism and can not represent any form of failure logic.In the treatment of the failure rate of components,the accurate value is brought into the calculation.In the actual industrial environment,the failure rate of components is related to the manufacturer and the operating environment,and the accurate value is taken Value is easy to cause information loss.In this paper,a reliability analysis method based on Dynamic Bayesian network(DBN)model is proposed to overcome the above shortcomings in the current reliability research of nuclear power plant emergency shutdown system.The method considers the influence of system time series failure mechanism and periodic maintenance,common cause failure and uncertainty of component failure rate parameters on system reliability,and uses T-S dynamic fault tree to determine dynamic Bayesian network Finally,based on the dynamic Bayesian network model,the system failure probability,component posterior probability and importance are calculated quantitatively.By comparing the posterior probability and importance of each component,the influence of component health status on the whole system is measured from two aspects to determine the weak points of the system.The experimental results show that the analysis results of this method are basically consistent with those of the comparative method,which verifies the correctness and applicability of this method.At the same time,as the mission time goes on,the reliability of the scram system is higher than that of the traditional analysis method without considering the dynamic and maintenance factors,which is more in line with the actual industrial production.The analysis of component importance indicates that component AI and pips-a have great influence on the system reliability,and they are the weak points of the system.It is necessary to pay more attention to the weak points of the system in the maintenance and troubleshooting work.