It has been a little over half a century since the first nuclear-powered warship, the submarine USS Nautilus, signaled that she was under way on nuclear power in 1955. Carriers like USS George H.W. Bush (CVN 77) are among the main beneficiaries of the naval revolution she represented. Nuclear power can drive such a ship at full speed for years on end. It provides the sort of electric power needed for modern electronics and, in the next carrier generation, for new devices like electric catapults and, possibly, lasers for self-defense. As a side benefit, a nuclear carrier does not suffer from the sort of smoke corrosion that used to destroy carrier radars and other electronics, not to mention carrier aircraft themselves.

Rickover’s decisive contribution was to realize as early as 1948 that he knew enough to build a prototype power plant. That was very courageous. Money was tight, and further studies might easily have uncovered some unsuspected problem.

The U.S. Navy’s journey to nuclear power began in 1946, when two scientists at the Office of Naval Research (ONR) pointed out that a submarine so powered would have unlimited underwater endurance at high speed. There was intense interest in high underwater speed because the Germans had pioneered it during World War II. The batteries which then powered submarines offered about an hour or less of endurance at maximum speed. The Germans had partly developed a closed-cycle Walter power plant that promised 10 hours at high speed. Nothing more seemed possible because a submerged submarine had no access to air for her diesel. The Germans had pioneered the snorkel, through which the diesel could breathe when the submarine was at periscope depth, but a submarine could not operate at maximum speed when snorkeling, and no submariner wanted to be limited to periscope depth.

At that time the only reactors in the world were used to make plutonium for atomic bombs. It was widely expected that atomic reactors would soon produce plentiful electric power, but that was a dream rather than a reality. Much of the enormous industrial team assembled to build the wartime atomic bombs (and the plutonium-making reactors) had dispersed, and the wartime bomb program run down to the point where, in 1946, the United States had no usable atomic weapons at all. Submariners were interested in new kinds of propulsion, but that generally meant various forms of closed-cycle engines, like the semi-developed German Walter plant. Surely it would be decades before nuclear power reached any sort of potential. The Bureau of Ships formed a small nuclear propulsion team, headed by Capt. Hyman Rickover.

Rickover was interested in the potential of nuclear power throughout the navy. His whole career had been built in naval propulsion machinery, and he had witnessed several major U.S. advances, leading up to the remarkably efficient and reliable high-pressure high-temperature power plants of World War II.

Rickover sponsored studies of various alternative power reactors from which heat might be extracted in the form of hot water or molten metal or gas. Rickover’s decisive contribution was to realize as early as 1948 that he knew enough to build a prototype power plant. That was very courageous. Money was tight, and further studies might easily have uncovered some unsuspected problem. Indeed, Rickover initially bet on liquid metal, and only later switched his main focus to water. However, his decision led to the construction of a prototype plant. Rickover further accelerated development by deciding that the land-based prototype would be matched by the prototype planned for installation in the first nuclear submarine. Changes to the prototype to solve problems as they were encountered would be duplicated in the submarine reactor. By 1950, the Bureau of Ships was designing the prototype submarine. Rickover contributed further by demanding that it be armed, as a combatant, rather than limited to power plant tests. There was already interest in arming such a submarine with guided missiles, but Rickover wanted to separate the test of the power plant from the tests of such new weapons.

Rickover’s program was viable despite tight defense funds because major companies like Westinghouse and General Electric saw it as an opening into a potentially huge civilian power market. In 1948, Rickover attended a Submarine Officers’ Conference in Washington that discussed progress in the new power plants. Captains in charge of various programs complained that companies would not assign their best engineers, because it seemed unlikely that the navy would ever build many such plants, and because they had no civilian applications. Then Rickover spoke. He had no such problems. The companies were building the necessary laboratories at their own expense. They were pushing their best people into the nuclear program. It turned out that his plant was ready years before any of the others – and it was inherently far superior, because the closed-cycle plants offered only a few hours underwater at high speed. Even in 1952, he offered weeks, and that soon extended to months and then years before a submarine had to be refueled.