A review of programmable logic controllers in advanced nuclear plant automation: challenges and future prospects

The evolution of advanced nuclear power plants (NPPs) necessitates the integration of robust and reliable automation systems to ensure safe, efficient, and continuous operation. Programmable Logic Controllers (PLCs), as critical components of nuclear instrumentation and control (I&C) systems, play a vital role in automating complex processes, managing reactor systems, and executing safety-critical functions. This review examines the application of PLC-based architectures in advanced nuclear plant automation, with emphasis on their adaptability, real-time processing capabilities, and fault-tolerant designs. Recent studies highlight PLCs' integration with digital instrumentation, supervisory control systems, and distributed control systems (DCS) to enhance plant-wide monitoring and control. The paper explores advancements in redundancy techniques, cybersecurity measures, and compliance with international nuclear safety standards, including IEC 61513 and IEEE 7-4.3.2. However, challenges persist, including aging legacy PLC systems, limitations in handling complex algorithms for predictive diagnostics, and vulnerabilities to cyber threats in increasingly networked environments. Additionally, the evolving regulatory landscape demands rigorous verification and validation (V&V) of PLC software and hardware to ensure compliance and operational safety. Future prospects involve transitioning towards more intelligent, AI-enhanced PLCs, incorporating model-based control strategies, and leveraging digital twin frameworks for predictive maintenance and operational optimization. This review synthesizes current research from reputable journals and technical reports to provide a comprehensive analysis of the role of PLCs in nuclear plant automation, identifying key challenges and charting future directions for next-generation nuclear energy systems.