Design of a Receding Horizon Control System for Nuclear Reactor Power Distribution

A receding horizon control method is applied to the axial power distribution control in a pressurized water reactor. The basic concept of receding horizon control is to solve on-line, at each sampling instant, an optimization problem for a finite future and to implement the first optimal control input as the current control input. Thus, it is a suitable control strategy for time-varying systems. The reactor model used for computer simulations is a two-point xenon oscillation model based on the nonlinear xenon and iodine balance equations and a one-group, one-dimensional, neutron diffusion equation with nonlinear power reactivity feedback that adequately describes axial oscillations and treats the nonlinearities explicitly. The reactor core is axially divided into two regions, and each region has one input and one output and is coupled with the other region. Through numerical simulations, it is shown that the proposed control algorithm exhibits very fast tracking responses due to the step and ramp changes of axial target shape and also works well in a time-varying parameter condition.