Nuclear engineering is the branch of engineering concerned with the application of the breakdown of atomic nuclei and/or other sub-atomic physics, based on the principles of nuclear physics. It includes, but is not limited to, the interaction and maintenance of nuclear fission systems and components— specifically, nuclear reactors, nuclear power plants, and/or nuclear weapons. The field may also include the study of nuclear fusion, medical and other applications of (generally ionizing) radiation, nuclear safety, heat/thermodynamics transport, nuclear fuel and/or other related (e.g., waste disposal) technology, nuclear proliferation, and the effect of radioactive waste or radioactivity in the environment