Robust optimal-integral sliding mode control for a pressurized water nuclear reactor in load following mode of operation

Abstract

A nuclear reactor is a complex, nonlinear, and time-varying system. External disturbances and uncertainty due to neutronic and thermal-hydraulics parameters variation contribute to reactor control challenges and safe operations. Thus, this paper presents a hybrid control system for a nuclear reactor core power control in the presence of a matched disturbance and uncertainties. The hybrid controller combines Linear Quadratic Gaussian/Loop Transfer Recovery (LQG/LTR) optimal control and a nonlinear Integral sliding mode control (ISMC). The nonlinear system of the reactor, which is based on point kinetics equations with three delayed neutron group is linearized to design the LQG/LTR. The Lyapunov theory is used to prove the finite-time convergence of the Integral sliding mode control. Furthermore, a comparative analysis of the hybrid control scheme, LQG/LTR, PID, and an ISMC is conducted with the nonlinear model. Simulation experiments reveal that the closed-loop hybrid control system is stable and achieves the best performance specifications in the presence of external disturbance and uncertainties.