A Reduced-Order Model of Boiling Water Reactor Linear Dynamics

The development of a reduced-order linear model of the linear dynamic behavior of boiling water reactors (BWRs) is reported. The model is based on a detailed study of the various physical dynamic processes involved. The major results of the work are (a) the pole-zero configuration of the transfer function of this type of reactor has been determined, (b) a minimum of three zeros and four poles is needed to properly represent this transfer function, (c) these poles and zeros have been associated with reactor physical processes such as fuel heat transfer dynamics, and (d) a reduced-order linear model composed of only five equations has been developed. With the appropriate parameters, the model very accurately represents the dynamic behavior of BWRs predicted by fine-mesh computer calculations.