Releasing of energy during interaction of nuclie of radiaoctive element
the energy released during nuclear fission or fusion, especially when used to generate electricity.

Nuclear enery means the energy which get from nucleus by combining and splitting. The common source of nuclear energy by splitting of atom is uranium it has atomic no. 235 which split and make kritium and berrium and a large amount of energy. Do you know we can light a bulb for 1 year by spillitng only a single atom of uranium.Another which energy release by combining of atom is hydrogen when two hydrogen atom combine with each other it make helium and produce a large amount of heat.