Research on Fault Mode Analysis Method of Nuclear I&C Software Based on Time Automata

This paper presents a novel fault mode analysis method for nuclear instrumentation and control (I&C) software based on timed automata. The proposed approach addresses the limitations of traditional fault analysis techniques in handling complex, real-time systems by accurately capturing the dynamic characteristics and intricate interaction patterns of nuclear I&C software. Key contributions include: (1) development of a timed automata-based modeling framework tailored for nuclear I&C software; (2) design of a comprehensive fault mode library compatible with timed automata models; and (3) implementation of an automated fault mode analysis algorithm leveraging model checking techniques. The method's efficacy is demonstrated through a case study on a digital reactor protection system, specifically the Reactor Coolant Pump speed protection subsystem. Results show significant improvements in fault mode identification rates, particularly for time-related faults, and enhanced capabilities in quantitative analysis and dynamic behavior capture compared to traditional methods. This approach provides a more rigorous and systematic tool for improving the reliability and safety of digital I&C systems in nuclear power plants, with potential applications in other safety-critical domains.