Nuclear submarine nuclear-powered submarine was first proposed in the United States Navy by the Naval Research Laboratory's Ross Gunn in 1939. Construction of the world's first nuclear powered submarine was made possible by the successful development of a nuclear propulsion plant by a group of scientists and engineers at the Naval Reactors Branch of the Bureau of Ships and the Atomic Energy Commission. In July 1951 the U.S. Congress authorized construction of the first nuclear-powered submarine, "Nautilus", under the leadership of Captain Hyman G. Rickover, USN (sharing names with Captain Nemo's fictional submarine in Jules Verne's "Twenty Thousand Leagues Under the Sea",
Nuclear weapons and the United Kingdom remain classified. Much of the HEU supplied by the US was used not for weapons, but as fuel for the growing fleet of UK nuclear submarines. Under the MDA, the US supplied the UK with not just nuclear submarine propulsion technology, but a complete S5W pressurised water reactor of the kind used to power the US submarines. This was used in the Royal Navy's first nuclear-powered submarine, , which was launched in 1960 and commissioned in 1963. The S5W had a Nuclear reactor core that used uranium enriched to between 93 and 97 per cent uranium-235. Reactor technology was transferred