Common Cause Failure Analysis of Feedwater System in Marine Nuclear Reactors Based on GO Methodology

Feedwater system is divided into two parts: feedwater making and feedwater supplying.Two procedures are carried out in analyzing the feedwater system according to different working condition.In the first stage,the effect of common cause component group 2 to the part of feedwater supplying is analyzed,and in the second stage,the effect of common cause component group 1 and 2 to the whole feedwater system is comprehensively analyzed.This paper respectively analyzes the reliability of feedwater system in two stages with GO Methodology.Firstly,the model of system and construct the GO chart of feedwater system is constructed by analyzing the system,and then the system unavailability in two stages is calculated based on the GO algorithm dealing with common cause failures and the contribution of common cause failure to it.The analysis results show that the common cause failure greatly affects the system reliability and the GO algorithm is the effective and practical method to analyze the system with common cause failure.