[en] A hybrid computer simulation of a nuclear power plant is described that was used to study the reactor core axial power distribution and to improve its control during loading and unloading maneuvers (load follow). Such control is necessary to prevent subsequent adverse operating conditions due to core xenon redistribution. The novelty of this approach lies in the implementation and organization of the mathematical models. The obtained results prove that the features of the hybrid computer approach, even in a small scale installation, can be satisfactorily used if the models are carefully chosen and the modeling detail and accuracy requirements carefully assessed