In this paper, a new concept of the Reactivity Trace Curve (RTC) for reactor power control is presented. The concept is demonstrated for a reactor model with one group of delayed neutrons, where the reactivity trace curve is simply a closed form exponential solution of the RTC-differential equation identifier. An extended reactor model of multigroup (six groups) of delayed neutrons is discussed for power control using the RTC-method which is based on numerical solution of the governing equation for the RTC-differential equation identifier. In this numerical solution, an impeded analytical solution for the RTC-identifier in every sampling time step is used. Finally, the concept is applied to a more rigorous reactor model, namely; a model of multigroup of delayed neutrons with temperature feedback. The simulation studies for all of the above mentioned cases demonstrate the validity of the concept for reactor power control with absolute elimination of power shootings.