Reliability Modeling and Analysis of Reactor Protect System Based on Petri Net

Digital control is an inevitable trend in the development of nuclear power. The application of digital control systems in nuclear power plants not only improves the control capability of nuclear power plants, but also increases the complexity of the system. Traditional reliability analysis methods (such as event trees and fault trees) can only perform static analysis on the reactor protection system, but cannot reflect the impact of maintenance activities on system reliability. In the dynamic analysis method, the Markov model is usually applied to the exponential distribution, and the failure and maintenance process of the reactor protection system does not all obey the exponential distribution. In this paper, the Petri net method is used to model the reactor protection system, and the modules are modeled separately according to the function of the system, and finally the model is integrated. Modularization improves the flexibility and understandability of the model, shortens modeling time, and improves robustness. The proposed model was simulated using the GPenSIM tool, and the state reachability diagram of the system with or without maintenance process was obtained, and the probability of shutdown and refusal was obtained.