Uncertainty and disturbance estimator based spatial power control of advanced heavy water reactor

The advanced heavy-water reactor (AHWR) is large, modern vertical pressure tube nuclear reactor. It exhibits oscillations caused by disturbance in reactivity and leads to unequal spatial distributions of power and ultimately increases chances of fuel failures. Therefore, it is of utmost importance to control the reactivity of AHWR before it causes a hazard to the systems. This paper presents design of an uncertainty and disturbance estimator (UDE) based control strategy for power distribution control along with estimation of disturbance acting on the AHWR. The designed controller is applied to the 72nd-order multi-input nonlinear AHWR model. In order to investigate the robustness of the designed strategy different disturbance profiles are considered. The detailed simulation demonstrates the efficacy of controller to counter the disturbance effects while offering flexibility in tuning. The results show that the UDE based control performs better compared to optimal integral sliding mode control (ISMC). The stability of the overall system is proved.