nuclear submarine vs nuclear-powered submarine

nuclear submarine and nuclear-powered submarine both are nouns.

Word	Noun	Adjective	Verb	Adverb
nuclear submarine	Yes	No	No	No
nuclear-powered submarine	Yes	No	No	No

As nouns, nuclear submarine and nuclear-powered submarine are synonyms defined as:

nuclear submarine and nuclear-powered submarine: a submarine that is propelled by nuclear power

Other synonyms of nuclear submarine include nautilus.

nuclear submarine (noun)	nuclear-powered submarine (noun)
a submarine that is propelled by nuclear power	a submarine that is propelled by nuclear power