A coordinated control strategy for forced–natural circulation inter-switching process of integral pressurized water reactor

Achieving natural circulation under low power level, and forced circulation under medium to high power levels is a desirable operation scheme for the integral pressurized water reactor to obtain maneuverability and silence. Nevertheless, the transition process between forced and natural circulation is challenging, which usually fails due to inappropriate control. Thus, its coordinated control is crucial. To improve its control performance, a coordinated control strategy is proposed. A feed-forward compensation controller is proposed for the primary and secondary circuit coordination, and a dual feedback reactor power controller is designed for the primary circuit inner coordination. Meanwhile, an expert system is implemented to coordinate actuators such as control rods and coolant pumps. Results demonstrate that with the coordinated control strategy, although the variation of the regulation time of each key parameter is small, its overshoot has been greatly decreased, and the control performance is thus improved.