Abstract: A nuclear reactor monitoring device, a nuclear reactor control device, and a nuclear power generation plant, wherein a detector (103) for detecting the state quantity of a reactor core (68) in a nuclear reactor (12), an incore instrumentation and calculation unit (211) for generating reactor core performance data on the basis of the state quantity of the reactor core (68) detected by the detector (103), and a reactor core monitoring server main machine (231) for generating reactor core prediction data by predicting and computing the change with the passage of time of the reactor core (68) on the basis of a current reactor core operation condition and the reactor core performance data are provided, the reactor core monitoring server main machine (231) generates the reactor core prediction data when the reactor core performance data exceeds a preset prescribed range.

Abstract: An axial power distribution control device includes an axial offset calculation unit 52, a parameter calculation unit 53, and an axial offset determining unit 55. The axial offset determining unit 55 predicts whether a core axial offset of the power distribution is increased or decreased after a current time, based on a major axis of an ellipse drawn by the xenon parameter and the iodine parameter calculated by the parameter calculation unit 53 and the xenon parameter and the iodine parameter at the current time. This makes it possible to predict a change of the axial offset of the power distribution of a reactor for suppressing a xenon oscillation in the reactor.

Abstract: Parameters DAOPX (=AOP?AOX) and DAOIX (=AOI?AOX) are calculated based on axial offsets of the power distribution (AOX and AO1). A movement control of a control rod is then performed in such a manner that a plot point of a trajectory of the parameter DAOPX and the DAOIX is induced toward the major axis of an ellipse drawn by the trajectory, based on the parameters (DAOPX and DAOIX) and allowable ranges (DAOPX—L and DAOIX—L) obtained in advance. With this configuration, the xenon oscillation is suppressed by controlling the xenon oscillation in a simultaneous manner simply by controlling an axial power distribution in a reactor by a simple operation with a clear purpose.

Abstract: An axial power distribution control device includes an axial offset calculation unit 52, a parameter calculation unit 53, and an axial offset determining unit 55. The axial offset determining unit 55 predicts whether a core axial offset of the power distribution is increased or decreased after a current time, based on a major axis of an ellipse drawn by the xenon parameter and the iodine parameter calculated by the parameter calculation unit 53 and the xenon parameter and the iodine parameter at the current time. This makes it possible to predict a change of the axial offset of the power distribution of a reactor for suppressing a xenon oscillation in the reactor.