Possibility, admissability, and desirability of implementing pulsed stochastic regimes in boiling-water reactors with natural coolant circulation

A one-dimensional integral momentum model for the boiling-water channel and the point kinetic equations are used to study the conditions and mechanisms for the appearance of temporary pulses of stochastic regimes and regimes with pulsed turbulence of the neutron field in water-moderated water-cooled boiling-water reactors with natural circulation of the coolant. These self-excited oscillatory regimes occur as a result of a negative steam effect of reactivity. They consist of the fact that neutron bursts with random intensity occur in a reactors in random time intervals. Such regimes make it possible to increase substantially the power and size of boiling-water reactors. The methods proposed for controlling pulsed chaos make it possible to excite and suppress stochastic regimes and to regulate the amplitude of self-excited oscillations so that it does not exceed admissable limits. Small external perturbations have no effect on the characteristics of pulsed chaos. The results are obtained by numerical calculation of the self-excited oscillations.[PUBLICATION ABSTRACT]