Reliability modeling by extended GO-FLOW methodology for automatic control component and system at NPP

Reliability of system, structures and components plays a crucial role in ensuring the safe and stable operation of nuclear power plants. With the widespread application of automation in nuclear power plants, the role of the operator in main control room has been changing from actual implementation of control to supervision of the control process. Reliability monitoring of automatic control components and systems provides an insight of the ability of plant systems in realizing their expected goals over time. This paper presents an extension of GO-FLOW methodology in modeling automatic control component and systems from the perspective of cognitive process. Through the concept of hierarchical modeling, this paper designs an improved GO-FLOW model hierarchical modeling and analysis framework, which further increases the feasibility of modular modeling and model readability. Taking CVCS of nuclear power plant as an example, considering the control of ACP, the analysis and calculation of several scenarios are carried out in this study. In the course of the analysis, it was verified that the model is able to update automatically and realize the real-time system reliability monitoring function. The approach proposed in this paper is a general technique which could be extended further to describe more complex control logic.