Nuclear power apparatus is a term used to describe a device that utilizes nuclear energy to generate electricity. The most common type of nuclear power apparatus is a REACTOR, which is a seven-letter word. Reactors are typically composed of a core containing nuclear fuel, such as uranium, and a system of moderators and control rods to regulate the rate of the nuclear reaction. The heat generated by the reaction is then used to produce steam, which is used to turn turbines and generate electricity.