Control system design and simulation of HPR1000

Proportional-integral-derivative (PID) control is widely employed in pressurized water reactor (PWR) systems due to its simplicity and robustness. However, tuning for China’s third-generation nuclear reactor, the Hualong Pressurized Reactor (HPR1000), remains challenging. It features highly complex, nonlinear dynamics with multi-loop coupling and high-order responses, making traditional tuning methods ineffective while field testing frequently fails to meet strict performance standards. In this study, a systematic forward design scheme based on the frequency domain analysis method is proposed. By utilizing the relationship between the frequency domain and the time domain, the control system can be designed analytically. A mechanism model of HPR1000 is established based on the derived system equations. The transfer functions of each subsystem are obtained through linearization. Time domain specifications (overshoot, settling time) are converted into frequency domain specifications (phase margin, crossover frequency). Controllers designed from transfer functions meet all performance requirements in nonlinear closed-loop simulations and are directly applicable in the field. This method establishes a generalized forward design framework that can be extended to diverse reactor control systems.