Xenon and samarium concentrations changes occur in a nuclear reactor as a consequence of power level variations. To compensate for the reactivity introduced by these isotopes, the boron concentration in the reactor coolant also needs to be changed. Boron concentration changes result from boration or dilution operations. Both boration and dilution operations have economic effects due to the cost of boric acid and the treatment of the effluent. A method is presented that finds the nuclear power level change that leads to an optimization of the boration and dilution operations. The use of the method for practical applications is demonstrated by comparing the absolute reactivity change for the optimum power ramp and a ramp of ±3%/h. The numerical calculations are very fast. Thus, the method may be implemented in the process computer of any nuclear power plant.