This course aims to establish the professional background for nuclear engineering students, is an advanced course to the course of “Basic Principles and Theory of Fission Reactors”.  The contents of the course are emphasized at the key issues concerning the origins and applications of nuclear energy.  At the very beginning of the course, atomic and nuclear physics is reviewed, while the ways that radiation particles interact with matter is introduced subsequently.  Furthermore, the course directs to the practical aspects of nuclear power, nuclear reactors, and nuclear cycles.  Finally, the major part of the course leads to nuclear reactor theory which includes the topics such as criticality, neutron diffusion and moderation, one- and multi-energy-group models, and time-dependent neutronics behaviours.