Application of Forward FTF Method in Failure Analysis of Pilot-Operated Safety Valve

On the basis of studying the characteristics of Failure Modes,Effect and Criticality Analysis(FMECA) method and Fault Tree Analysis(FTA) method,a forward FTF method which integrates FMECA with FTA is built to analyze the failure of the nuclear Pilot-Operated Safety Valve.It is a comprehensive and exhaustive method which has considered the integrative effect caused by every function failure mode,hardware,software,artificial factor,environment and multiple failure modes.Through the qualitative analysis of the valve failure mode with the method,the most important failure modes of the valve system and important parts are found.A feasible method for failure analysis of the valve system is provided in this paper.