Some naturally occurring elements are unstable and have the potential to release energy – they are called radioisotopes. Many years ago, we realized that radioisotopes, if used in a controlled fashion could be a valuable source of energy to create electricity.
Through a series of nuclear and chemical reactions, radioisotopes are used to generate a controlled source of heat. That heat is used to convert water to steam. The steam is used to turn a turbine that spins a shaft around a fixed magnet that creates an electrical current. It’s pretty simple, electricity from steam created from the heat given off from a nuclear reaction.