Power Regulation Feature of a Reactor with Negative Feedback

The theoretical possibility of anomalous manifestation of negative feedback on coolant temperature in the form of a change in the reactor power with sign opposite to that of the introduced reactivity is analyzed. The analysis is performed using a simplified one-dimensional model of a reactor with one feedback on the coolant temperature. It is shown, on the basis of the approximations adopted, that the properties of a reactor with respect to a given effect are determined by a certain criterional complex of physical characteristics, for which numerical estimates corresponding to the appearance of anomalous self-regulation were obtained. Application of the criterion to real loads for VVÉR showed that there are prerequisites for appearance of such anomalies. It is shown that the manifestation of negative feedback examined here is consistent with the neutron-physical stability of a reactor.[PUBLICATION ABSTRACT]