The Dual-Input Describing Function in the Oscillation Analysis of a Nuclear Reactor System

The dual-input describing function concept is discussed with reference to a low-power nuclear reactor. Results of an earlier analysis, where the conrventional describing function of a low-power nuclear reactor was derived by using the Wentzel-Kramers-Brillouin solution of the kinetics equations, are used to obtain the dual-input describing function of a low-power nuclear reactor. The dual-input describing function technique is applied to investigate the self-oscillations of a low-power nuclear reactor with external feedback. For a suitable frequency characteristic of the feedback, ÿxistence of an unstable limit-cycle is shown.