Controller Design and Stability Analysis of an MSR Plant Based on a Nonlinear Distributed-Parameter Model

A molten-salt reactor (MSR), in which the nuclear waste can be separated and taken away from the liquid fuel through online chemical treatment, has remarkable advantages in safety and economics. To ensure the safe operation of an MSR plant, it is necessary to carry out a controller design and stability analysis of the whole system. In this work, a nonlinear distributed-parameter model of an MSR plant with a graphite-moderated liquid core was established and verified by the reference model. By applying a joint feedforward and feedback control strategy, the power controller and steam temperature controller were designed to adjust the plant load. The Nyquist criterion was used to assess the stability of the control system. The system responses to four different perturbations at the nominal power level were simulated, and the results show that the designed controllers have good reliability. In addition, the control performance was tested in two load change cases: a step load reduction and a linear load change. The dynamic response characteristics of the system parameters show that the developed control system based on the nonlinear distributed-parameter model is capable of fast and accurate regulation.