Direct method of search for optimal xenon oscillation control based on new concept of axial offsets

A new concept for control of Xe oscillations is applied to solve an optimal control problem. The concept is based on two additional newly defined axial offsets, AOi and AOx together with the conventional axial offset AOp of axial power distribution. The AOi and AOx are the axial offsets of power distributions which would give the current I and Xe distributions under equilibrium condition, respectively. Using these three AOs the necessary condition for a Xe oscillation to be controlled or suppressed can be clearly and simply expressed. In other words, when these three AOs meet together that is the point that the Xe oscillation dies out. Using this simple requirement as the target for Xe oscillation control, the solutions of some optimal problems can also be obtained quite straightforwardly. An example is presented to solve the shortest control time problem known as bang-bang control. (author)