nuclear power vs nuclear energy

nuclear power and nuclear energy both are nouns.

Word	Noun	Adjective	Verb	Adverb
nuclear power	Yes	No	No	No
nuclear energy	Yes	No	No	No

As nouns, nuclear energy is a hypernym of nuclear power; that is, nuclear energy is a word with a broader meaning than nuclear power:

nuclear power: nuclear energy regarded as a source of electricity for the power grid (for civilian use)
nuclear energy: the energy released by a nuclear reaction

Other hypernyms of nuclear power include atomic energy.

nuclear power (noun)	nuclear energy (noun)
nuclear energy regarded as a source of electricity for the power grid (for civilian use)	the energy released by a nuclear reaction