Multivariable modeling and nonlinear coordination control of nuclear reactor cores with/without xenon oscillation using H∞ loop shaping approach

Abstract This investigation is to achieve multivariable modeling for a pressurized water reactor core with/without iodine-xenon dynamics and design nonlinear core multivariable coordination control systems with stability analyses for simultaneous regulations of the core power and axial power difference during load following/transient load maneuvers. A two-point based multivariable model for this nonlinear core with iodine-xenon and that for the core without iodine-xenon are respectively built adopting the power regulating rod and the axial offset regulating rod as inputs and ignoring boron, and are then linearized. The H ∞ loop shaping control with robustness is utilized to contrive a coordination controller of each linearized model and this controller is applied to the nonlinear model corresponding to the linear model. The nonlinear model with iodine-xenon and its coordination controller construct the nonlinear core load following coordination control system, and the nonlinear model without iodine-xenon and its coordination controller structure the nonlinear core transient load coordination control system. One stability theorem is deduced to analysis stability of the two nonlinear control systems. Eventually, the two nonlinear coordination control systems are simulated. Simulations show that the systems possess the desired decoupling control ability for coordination regulations of multi-parameter and good dynamic performance, and are effective.