Time optimal spatial offset control in nuclear power reactors

The problem of minimal time control of xenon spatial oscillations in nuclear power reactors is investigated and the effect of constraints on the control variable (rod position), spatial offset magnitude and rate of change, which is closely related to the rate of change of the local power density, is studied. The concept of spatial offset phase plane is extended to include direct reference to the measured spatial offset. The optimal constrained and unconstrained trajectories and switching curves are analyzed in the phase plane. Work done on the Carnegie-Mellon University digital reactor simulator confirmed the success of the derived theoretical results. Operational strategies that embody both the strength of the theory and the simplicity needed for practical application are recommended.