Nuclear Engineering is the branch of engineering concerned with the design and construction and operation of nuclear reactors. In the sub-field of nuclear fission, it particularly includes the interaction and maintenance of systems and components like nuclear reactors, nuclear power plants, and/or nuclear weapons. Nuclear engineers research and develop the processes, instruments, and systems used to derive benefits from nuclear energy and radiation. Many of these engineers find industrial and medical uses for radioactive materials, for example, in equipment used in medical diagnosis and treatment.