The logic of the time-optimal solution to the xenon shutdown problem for a point reactor model has been successfully applied to an actual reactor system. Spatial integration of the flux-square weighted xenon concentration was used. The predetermined power variation with time successfully held the xenon boundary and created a final shutdown (target) trajectory whose maximum was within three percent of the specified boundary based on the total reactivity variation of the program. Although digital computer calculation, occasionally using trial-and-error techniques, was necessary to predict the power-time shutdown program, the computer requirements were not excessive. Approximately 7 h of additional reactor operation was utilized to prevent a 16 h period during which xenon buildup would have prevented reactor operation.