The increase of the intermittent renewable energies Contribution is a major challenge in the context of the French energy transition, with renewable energies forecasted to be around 30% of the total production by 2030, thus increasing the manageability required of nuclear power plants. This works aims at optimizing load-follow operations on French 1300MW pressurized water reactors, according to values of interests (volume of boron effluents and axial stability) by changing the operating parameters of the rods. A simulator oriented reactor model is designed, coupling a 0D secondary model and a core model with a model including 3D neutronics, multi1D thermal-hydraulics and fuel thermal effects. A simplified controller imitating the current “G mode” operator is presented. Finally, a study of the fitness landscape of the optimization problems shows the potential of this model and these parameters for the optimization process.