Introduction to the basic physics of nuclear energy and radiation, with an emphasis on the unique attributes and challenges of nuclear energy as a low-carbon solution. Discusses peaceful applications of ionizing radiation, such as reactors for materials science research, nuclear medicine, and security initiatives. Explores fission energy, establishing the scientific, engineering, and economic basis for power reactors. Describes the latest advances in nuclear reactor technology. Introduces magnetic fusion energy research, with lectures covering the scientific and engineering basis of tokamaks, the state-of-the-art in world fusion experiments, and the MIT vision for a high-magnetic field fusion reactor. Uses radiation detection equipment to explore radioactivity in everyday life. Subject can count toward the 6-unit discovery-focused credit limit for first year students.