The strategic line of development of a nuclear power system based on fission and fusion reactors which ensures electricity generation on a specified scale, solves the fuel problem for a long-term outlook, and secures the lowest risk of environmental contamination is presented. A contemporary view of prospects of developing the nuclear power industry on the basis of replacement of thermal reactors in the future by fast reactors, owing to a long duration of this process and the necessity of additional resources of natural uranium, forces us to consider the possibility of implementation of this strategy as unlikely. In addition, the fuel cycle of fast reactors requires the quick reprocessing of the highly active spent fuel, and because of this, the fuel cycle will have a high risk of a negative radioactive effect on the environment. The transition of the nuclear power industry to fast reactors will lead to a full change of the infrastructure related to reactor construction and operation. In the development of a nuclear power system with fusion and fission reactors, the demands for natural uranium will correspond to current estimates of economically effective stockpiles, the risk of radioactive contamination of the environment associated with the spent fuel reprocessing will be the lowest, and the contemporary infrastructure of the nuclear power industry will be maintained, i.e., the prevalence of generating capacities based on thermal neutron reactors. Thus, the integration of nuclear power production by fusion and fission reactions into a unified system creates a significant synergetic effect, in which the deficiencies of each technology are compensated by another technology of nuclear power production.