USS Nautilus was the world's first nuclear-powered submarine. (http://hnsa.org/ships/nautilus.htm)

As Duane Roelands says, Nautilus. It was named Nautilus because of the book,20,000 leagues under the sea. By Jules Verne. In the book it was the submerine of Captain Nemo.

Nautilus?

The Nautilus

USS Nautilus. "The USS Nautilus (SSN-571) was the world's first operational nuclear-powered submarine and the first vessel to complete a submerged transit across the North Pole. In July 1951 the US Congress authorized the construction of a nuclear-powered submarine for the U.S. Navy, which was planned and personally supervised by Admiral Hyman G. Rickover, known as the "Father of the Nuclear Navy."[1] On December 12, 1951 the U.S. Department of the Navy announced that the submarine would be called Nautilus — the sixth US Navy vessel so named — and would carry the hull number SSN-571." For more, please see http://en.wikipedia.org/wiki/USS_Nautilus_(SSN-571)

It was the Nautilus, which was named after Jules Vern's Novel "Twenty Thousand Leagues Under the Sea", the submarine that was so fantastic.

The USS Nautilus (SSN-571) as others have already posted. The start of the Naval Nuclear Propulsion program is pretty interesting, and a textbook case for modeling a successful nuclear power program anywhere. Then Captain Hyman G. Rickover, the Father of the Nuclear Navy (Peace be upon him) was chosen, along with a handful of other men, to attend what is now known as the Oak Ridge National Laboratory to study with a project to design an electric power plant. This project started in 1946, but Rickover wasn't initially selected, though he applied then. His selection was a kind of sly, underhanded political move within the Navy for a reason. The reason was that there were people among the Admiralty which had no interest in nuclear power for propulsion, for a variety of reasons. One was it upset the traditional thinking, and another was it would divert money away from what others considered more important things. Because these people had no interest in nuclear power at all, they had a vested interest in seeing it fail. Enter Captain Rickover. Rickover was not well liked. At all. Which made his selection one which the Admiralty would readily approve, because putting someone not liked in charge of a program nobody wanted was a good idea...they could kill two birds with one stone. However, Rickover was NOT a person to be trifled with. As one person once observed, Captain Rickover was a person who would take the shortest route between two points and not care how many Admirals he bisected along the way. Because of this, Admiral Mills figured Rickover was the best man to establish a Nuclear Propulsion program in the Navy, if Rickover could be convinced it was feasable. When Rickover WAS selected, he went as the deputy director of the entire program, which gave him access to EVERYTHING about the project. Which suited his way of doing business perfectly. His philosophy had always been to assume as much responsibility as he could, most especially if nobody else wanted to or if it wasn't precisely defined. And sometimes even beyond that. And because nobody else wanted anything to do with the program at all, Rickover took it over entirely and ensured the he alone would hold that power. Which became important later. Because of this consolidation of control and authority, all responsibility for the entire program rested with him and him alone. We'll see why that's important in a little bit. By 1949, Rickover was head of both the Naval and the civilian departments concerning Naval Nuclear Propulsion. He lead the efforts to build both the worlds first nuclear powered submarine and the worlds first civilian nuclear power plant (Shippingport Atomic Power Station). Under Rickover's direction, the worlds first nuclear powered propulsion plant was built, small enough to fit into the hull of a submarine that was 28 feet across. His prescribed method was to build a wooden mockup of the submarine and then design and build the power plant to fit inside of that. The construction of the ship, the USS Nautilus, followed a schedule that was one year behind that of the prototype plant being built for it. What this meant was the construction of the ship, and the reactor plant with it, was occurring WHILE the first plant was being designed, built, and tested. This had never been done before, to build a ship before the propulsion plant could even be tested. To appreciate what this accomplishment entails in the early 1950's, consider the following before the S1W/S2W nuclear propulsion plant for the Nautilus was built: A megawatt scale reactor took up a city block, this was the first high temperature reactor ever built, the physics for this reactor had yet to be developed before this program, the design and construction methods did not exist before this program, no engineering data yet existed for the exotic metals yet to be used in this program. Despite all this, the first nuclear propulsion plant was designed and built to fit into the hull of a submarine only 28 feet across. And the biggest reason this happened was because Rickover was in charge of BOTH the civilian AND the Naval nuclear power programs. In 1951, Congress authorized the construction of the first nuclear powered submarine. In June of 1952 the keel of the Nautilus was laid and a year and a half later she was launched in January of 1954. One year later, on January 17, 1955, the worlds first nuclear powered submarine went to sea "Underway on Nuclear Power". Rickover had a work ethic that was, by any measure, nothing short of phenomenal. He accepted no short cuts and no concessions against safety. His view point was that anybody working on the project would be not only proud, but confident enough that their own sons could operate this propulsion plant with safety. Once the program proved to be successful, he gained even more enemies within the Admiralty. Now that the program was proven to be a success, there were those who wished to oust Rickover and take over the project for themselves. But by then, Rickover was the acknowledged head of the entire program, all the way up to and including Congressional recognition and approval of this. Which did not sit well with the Admiralty. When it became apparent that Rickover could not be displaced, the plan was to oust him by attrition. Once passed over for promotion enough times, he would be forced to retire from the Navy, leaving the position open for someone else to fill. And since the Admiralty determined who was advanced to the rank of Admiral, this simply was not going to happen. When the time came for Rickover to be forceably retired, however, Congress got d*mned suspicious. It was absolutely apparent to them that Rickover was nothing short of stellar, and therefore it was not understood why their favorite person in charge of this huge, politically powerful revelation in Naval capabilities was NOT promoted to Admiral and thus being forced out of the Navy. Congress did not wish to have to deal with Admiralty that was not as open and forthcoming with them as Rickover had been. So an ultimatum was put forth to the Admiralty: They could refuse to promote Rickover to Admiral if they wished, since that was their responsibility and authority. But if they didn't, Congress would conduct a full scale investigation into the advancement process of the Admiralty, from one end to the other. Rather than have Congress meddle in Naval advancement affairs, the Admiralty promoted Rickover. When he finally left the Navy in 1982, Rickover was a four star Admiral. And as a testiment to Rickover, the entire program, including the ground breaking USS Nautilus, never had one reactor accident. Pretty darned amazing, considering what it took and the short amount of time it took to get from absolutely NOTHING to the Nautilus steaming under her own power.