Nuclear power is generated inside a plant called a reactor. The power source is the heat produced by a controlled nuclear fission chain reaction. This reaction involves an element such as uranium or plutonium being struck by a neutron and splitting. The result of the fission of these large atoms is the creation of new, smaller atoms as byproducts as well as radiation and more neutrons. Those neutrons speed out and strike other uranium/plutonium atoms, creating a chain reaction. The chain reaction is controlled by neutron moderators, which vary depending on the design of the reactor. These can be anything from simple water. Heat energy is released from the fission, and the nuclear reactor uses the heat to produce electricity in exactly the same manner as any other thermal-based power plant. The heat converts water into steam, and the steam is used to turn the blades of a turbine, which runs the generator.