or atomic energy
Energy released from atomic nuclei in significant amounts.
In 1919 nucleus of an atom . This led ultimately to the discovery of the neutron and the release of huge amounts of energy by the process of nuclear fission . Nuclear energy is also released as a result of nuclear fusion . The release of nuclear energy can be controlled or uncontrolled. Nuclear reactors carefully control the release of energy, whereas the energy release of a nuclear weapon or resulting from a core meltdown in a nuclear reactor is uncontrolled. See also chain reaction , nuclear power , radioactivity .