Stochastic oscillations in a nuclear reactor with a relay-type regulating system

The objective of this study was to examine the self-excited oscillations that occur when a reactor is subject to oscillating instability and the reactor regulating system relays have zones of instability and hysteris. As this is important in determining the design characteristics of the reactor regulating system, the time interval between regulating system activations was also examined. In order to accomplish this, the six-group reactor kinetics equations were solved, and various models of reactivity feedback due to the regulating systems were assumed. Extensions of this concept to reactivity feedback due to void formation (BWRs) and xenon poisoning were briefly discussed.