Processor-in-the-Loop Simulation and Multivariable Control System Design for Pressurizer System in Nuclear Power Plants
摘要
The stable operation of Pressurized Water Reactors (PWRs) critically depends on the effective control of the pressurizer (PZR), a nonlinear multi-input multi-output (MIMO) subsystem responsible for regulating primary coolant pressure and water level during both steady-state and transient conditions. This study proposes a Fuzzy Logic-based Adaptive PID (APID) controller for simultaneous pressure and level control in the PZR system. In contrast to contemporary machine learning (ML) and artificial intelligence (AI)-based control methods which often entail high computational cost, limited interpretability, and certification challenges the proposed APID controller emphasizes real-time feasibility, transparency, and regulatory compliance, which are essential in nuclear safety applications. The controller retains the intuitive structure of classical PID control while integrating rule-based fuzzy logic for online gain adaptation. This hybrid architecture facilitates explainable decision-making, enhances operator trust, and supports formal verification. The controller was deployed on a low-cost STM32F407 microcontroller, meeting strict memory and timing constraints, and was validated through extensive Processor-in-the-Loop (PIL) testing. Utilizing a high-fidelity, nonlinear two-region thermodynamic model of the PZR, simulation results across diverse operating scenarios including load-following transients, coolant flow loss, and setpoint shifts demonstrate significant performance enhancements over conventional PID controllers. Key improvements include up to 90% reduction in pressure overshoot, faster settling times, minimal steady-state error, and robustness against large disturbances, all achieved without the unpredictability commonly associated with data-driven ML models. By bridging adaptive intelligent control with embedded real-time constraints, this work offers a certifiable, high-performance, and transparent solution for next-generation nuclear reactor control systems, aligning theoretical innovation with practical deployment.