AbstractA CANDU‐CANDU(Th/Pu)‐LMFBR(PuO2) nuclear power system is considered, on a 65 year time horizon. The system is characterized by a number of independent variables and integral parameters that depend on them. In performing the optimization of the system we outline first of all the following components of the independent variable vector:(1) DT1—the delay time in reprocessing Pu from CANDUs, (2) DT2—the delay time in reprocessing Pu partially consumed in the CANDU (Th/Pu)s, (3)b3—the fuel burn‐up in CANDU (Th/Pu)s, (4)q—the control parameter of the total power growth. The components of the independent variable vector, also called decision variables, are subjected to some direct restrictions. In this paper it is admitted that, from the multitude of integral parameters of the system, the annual electric energy has the greatest importance in the case of a non‐econometric approach. This is the objective function of the system optimization problem and depends on the independent variable vector or decision vector. In addition, from the fuel resource point of view, the Unat and Pu cumulative consumptions have a special importance. These are called restriction functions because one looks for the decision vector subject to some direct restrictions (on components) so that, some restrictions on the consumption functions being satisfied, a maximum of the annual electric energy produced in the system at the end of the considered interval is obtained. In this way, the problem has a clear structure of an optimization model of non‐linear programming type and it can be treated in specific way for a given field of the above restriction function values. As a result, a set of optimal solutions for development of a CANDU‐CANDU(Th/Pu)‐LMFBR(PuO2) system, of interest from a nuclear energy policy point