Nuclear power was a technology widely used in Earth naval vessels during the late 20th century.
This fact was stated by Spock upon the arrival of the HMS Bounty to 1986, with regards to the need to repair the ship's dilithium crystals.
This led the crew to discover the aircraft carrier USS Enterprise for what thet sought, as it was powered by nuclear reactors. (Star Trek IV: The Voyage Home)
External link Edit