Non linear Dynamic Inversion based controller design for load following operations in Pressurized Water Reactors with bounded Xenon oscillations

Nuclear Power Plants mostly act as base-load stations mainly because of constraints on rate of reactivity addition. In order that such plants operate as commercially viable entities, it is necessary that they are capable of operating as load following stations. The inherently self-regulating nature of a Pressurized Water Reactor (PWR) makes it a natural choice for load followers. However, this entails an associated problem of periodic variation in spatial concentrations of the burnable neutron poison Xenon which alters the spatial flux profile substantially within the reactor core, and this phenomenon is known as Xenon oscillation. This paper proposes a nonlinear controller design methodology based on Nonlinear Dynamic Inversion (NDI) which is coupled with constrained optimization to develop a tracking controller that achieves load following operation of a PWR over a wide range of reactor power with no Xenon oscillations and satisfies the operational constraints of the reactor imposed by reactivity worth of the control devices and allowable fuel and coolant temperatures.