The CJEZ course introduces students with state-of-the-art problems of nuclear power utilization. It familiarizes students with fundamental physics processes in atoms and atomic nuclei, defines nuclear energy, neutron nuclear reactions, nuclear fission, etc. If defines all processes from general one to the most special; it begins from physics of atomic nucleus and finishes with nuclear heat transfer in nuclear reactors. The emphasis is focused on understanding of problems inside nuclear reactor, on practical examples, computer utilization for nuclear reactor calculations, and practical courses at training nuclear reactor VR-1 in Prague and research reactor LR-0 in Rez. Course contains also physics of shielding and definition of basics of nuclear safety and regarding calculcations. Each nuclear equipment and facility, which is important from nuclear reactor operation point-of-view is described.