Nonlinear PI output power regulation in a light water reactor

Robust nonlinear control of the load following operation has been attempted for a nuclear facility with a pressurized water reactor. A multi-linear model of the plant has been employed to contrive an appropriate proportional-integral (PI) controller further applied to the original nonlinear system. PI parameters (kP,kI) are adopted within the largest intersecting stability regions for all local models. Plant uncertainties due to the variable model parameters are moreover characterized within a multiplicative layout and the largest bound for the local models is assigned as the overall system uncertainty. Nyquist stability criterion is accordingly investigated for the robust stability of the PI controller. The proposed strategy is finally applied in two realistic load following scenarios addressed as output trajectory tracking problems. Results confirm a successful robust control practice for the nonlinear plant with a feasible control rod drive current as the regulating input.