Nuclear Energy

Nuclear energy is the energy that is trapped inside each atom. Presently, nuclear energy provides approximately 16% of the world's electricity.

Nuclear energy is produced naturally and in man-made operations under human control.

Naturally: Some nuclear energy is produced naturally. For example, the Sun and other stars make heat and light by nuclear reactions.

Man-Made: Machines called nuclear reactors, parts of nuclear power plants, provide electricity for many cities. Man-made nuclear reactions also occur in the explosion of atomic and hydrogen bombs.

Nuclear energy is released by three exoenergetic (or exothermic) processes

Radioactive decay, where a neutron or proton in the radioactive nucleus decays spontaneously by emitting either of the particles, electromagnetic radiation (gamma rays), neutrinos (or all of them).
Fusion, two atomic nuclei fuse together to form a heavier nucleus.
Fission, the breaking of a heavy nucleus into two (or more rarely three) lighter nuclei.

Currently all nuclear energy production comes from nuclear fission.

How a Nuclear Power Plant Works
A nuclear power plant is basically a steam power plant that is fueled by a radioactive element, like uranium. The radioactive element is placed in a reactor and the individual atoms are allowed to split apart. This process called fission releases great amounts of energy, which is used to heat water to produce steam. The steam turns turbines to generate electricity.
From here, the mechanics of a steam power plant take over. The steam pushes on turbines, which force coils of wire to interact with a magnetic field. This generates an electric current.