Patent Number: 
Section: abstract

This document's object is to provide an axial power distribution control method in which only the control of an axial power distribution in a nuclear reactor with a simple operation with a clear operational target keeps the control of a xenon oscillation, thereby suppressing the xenon oscillation to an extremely small magnitude in advance at the same time. An axial power distribution control method comprises an axial offset calculation step of calculating an axial offset of the current power distribution (AOP) and axial offsets of the power distributions (AOX, AOI) which would give the current xenon and iodine distributions under equilibrium conditions, respectively, based on relative powers (PT, PB) in the upper and lower halves of the nuclear reactor core, a parameter calculation step of calculating parameters (DAOPX, DAOIX), a trajectory display step of displaying a trajectory to plot the parameters (DAOPX, DAOIX) on one and the other axis, respectively, an allowable range excess judgment step of judging if the axial offset of the current power distribution (AOP) exceeds an allowable range, an alarming step of giving the alarm when the AOP exceeds the allowable range, and a control rod moving step of controlling the movement of control rods to guide the plot to the major axis of an ellipse formed by the trajectory of said parameters upon receipt of the alarm.