Study on common cause failure in multiple redundant system

To enhance the safety of nuclear power plants, redundant designs are frequently implemented within safety systems. Probabilistic safety analysis further reveals that common cause failures (CCF) of redundant systems significantly contribute to risk. When a specific component fails, it not only impacts the redundant design but also affects the functioning of components that have not failed. This paper builds upon the common cause failure model widely utilized in probabilistic safety analysis. It explores and establishes an accurate quantitative method for assessing common cause failures in the context of component failure. This approach aims to provide a rational evaluation of the safety levels of nuclear power plants and support the risk assessment and management efforts. The efficacy of this method is demonstrated through a case study analysis of a multi-redundancy design.