Dynamic Surface-Based Disturbance Observer Control Law Design for Nuclear Reactor Power Level Control in Load-Following Operation

Load-following operation in nuclear power reactors presents significant challenges due to model uncertainties, unmeasured states, and external disturbances. To address these issues, this paper proposes a robust control strategy that combines a dynamic surface control technique with a nonlinear disturbance strategy. The proposed approach is specifically designed for nuclear reactors operating under varying load demands, where both control input and output disturbances are present. The disturbance observers are employed to estimate unknown system states and unmatched and matched disturbances.These estimations are then integrated into the control law to enhance system performance and resilience. The global asymptotic stability of the closed-loop system is rigorously proven using the Lyapunov stability theory. Simulation studies demonstrate the superior performance of the proposed method compared to an optimized proportional-integral-derivative and the famous active disturbance rejection control law, particularly in disturbance rejection and load-following accuracy.