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The S2G reactor was a naval reactor used by the United States Navy to provide electricity generation and propulsion on warships, and the only liquid metal cooled reactor yet deployed by the US Navy. The S2G designation stands for:
An S2G was the initial power plant of USS Seawolf (SSN-575). This was one of three sodium cooled reactors (the core was moderated) ordered for the Seawolf program at the same time as three PWR units were ordered to support the USS Nautilus (SSN-571) program; In each case, one reactor was land-based for training and research, one intended for installation on a submarine, and one spare. The land-based unit corresponding to S2G was S1G reactor. The reactor core was beryllium-moderated. [1] [2]
Persistent superheater problems on Seawolf caused the superheaters to be bypassed, resulting in mediocre performance. This and concern for the dangers posed by liquid sodium coolant led to the PWR type being selected instead as the standard US naval reactor type, and the S2G on Seawolf was replaced by the spare S2Wa reactor from the Nautilus program.
The Atomic Energy Commission historians' account of the naval sodium-cooled reactor experience was:
Although makeshift repairs permitted the Seawolf to complete her initial sea trials on reduced power in February 1957, Rickover had already decided to abandon the sodium-cooled reactor. Early in November 1956, he informed the Commission that he would take steps toward replacing the reactor in the Seawolf with a water-cooled plant similar to that in the Nautilus. The leaks in the Seawolf steam plant were an important factor in the decision but even more persuasive were the inherent limitations in sodium-cooled systems. In Rickover's words they were "expensive to build, complex to operate, susceptible to prolonged shutdown as a result of even minor malfunctions, and difficult and time-consuming to repair." [3]
United States naval reactors are nuclear reactors used by the United States Navy aboard certain ships to generate the steam used to produce power for propulsion, electric power, catapulting airplanes in aircraft carriers, and a few minor uses. Such naval nuclear reactors have a complete power plant associated with them. All commissioned U.S. Navy submarines and supercarriers built since 1975 are nuclear powered, with the last conventional carrier, USS Kitty Hawk, being decommissioned in May 2009. The U.S. Navy also had nine nuclear-powered cruisers with such reactors, but they have since been decommissioned also.
The S1G reactor is a naval reactor used by the United States Navy to provide electricity generation and propulsion on warships. The S1G designation stands for:
The D1G reactor was a prototype naval reactor designed for the United States Navy to provide electricity generation and propulsion on warships. The D1G designation stands for:
A pressurized water reactor (PWR) is a type of light-water nuclear reactor. PWRs constitute the large majority of the world's nuclear power plants. In a PWR, the primary coolant (water) is pumped under high pressure to the reactor core where it is heated by the energy released by the fission of atoms. The heated, high pressure water then flows to a steam generator, where it transfers its thermal energy to lower pressure water of a secondary system where steam is generated. The steam then drives turbines, which spin an electric generator. In contrast to a boiling water reactor (BWR), pressure in the primary coolant loop prevents the water from boiling within the reactor. All light-water reactors use ordinary water as both coolant and neutron moderator. Most use anywhere from two to four vertically mounted steam generators; VVER reactors use horizontal steam generators.
USS Thresher (SSN-593) was the lead boat of her class of nuclear-powered attack submarines in the United States Navy. She was the U.S. Navy's second submarine to be named after the thresher shark.
USS Seawolf (SSN-575) was the third ship of the United States Navy to be named for the seawolf, the second nuclear submarine, and the only US submarine built with a liquid metal cooled (sodium), beryllium-moderated nuclear reactor, the S2G. Her overall design was a variant of Nautilus, but with numerous detail changes, such as a conning tower, stepped sail, and the BQR-4 passive sonar mounted in the top portion of the bow instead of further below. This sonar arrangement resulted in an unusual bow shape above the water for a U.S. submarine. Originally laid down in 1953, her distinctive reactor was later replaced with a standard pressurized water reactor, the replacement process lasting from 12 December 1958 to 30 September 1960.
USS Nautilus (SSN-571) was the world's first operational nuclear-powered submarine and on 3 August 1958 became the first submarine to complete a submerged transit of the North Pole. Her initial commanding officer was Eugene "Dennis" Wilkinson, a widely respected naval officer who set the stage for many of the protocols of today's Nuclear Navy of the US, and who had a storied career during military service and afterwards.
A nuclear submarine is a submarine powered by a nuclear reactor, but not necessarily nuclear-armed. Nuclear submarines have considerable performance advantages over "conventional" submarines. Nuclear propulsion, being completely independent of air, frees the submarine from the need to surface frequently, as is necessary for conventional submarines. The large amount of power generated by a nuclear reactor allows nuclear submarines to operate at high speed for long periods, and the long interval between refuelings grants a virtually unlimited range, making the only limits on voyage times being factors such as the need to restock food or other consumables.
The S1W reactor was the first prototype naval reactor used by the United States Navy to prove that the technology could be used for electricity generation and propulsion on submarines.
Nuclear marine propulsion is propulsion of a ship or submarine with heat provided by a nuclear reactor. The power plant heats water to produce steam for a turbine used to turn the ship's propeller through a gearbox or through an electric generator and motor. Nuclear propulsion is used primarily within naval warships such as nuclear submarines and supercarriers. A small number of experimental civil nuclear ships have been built.
The light-water reactor (LWR) is a type of thermal-neutron reactor that uses normal water, as opposed to heavy water, as both its coolant and neutron moderator; furthermore a solid form of fissile elements is used as fuel. Thermal-neutron reactors are the most common type of nuclear reactor, and light-water reactors are the most common type of thermal-neutron reactor.
Naval Reactors (NR), which administers the Naval Nuclear Propulsion Program, is an umbrella term for the U.S. government office that has comprehensive responsibility for the safe and reliable operation of the United States Navy's nuclear reactors "from womb to tomb." A single entity, it has authority and reporting responsibilities within both the Naval Sea Systems Command and the National Nuclear Security Administration (NA-30). Moreover, the Director of Naval Reactors also serves as a special assistant to the Chief of Naval Operations for Naval Nuclear Propulsion.
A liquid metal cooled nuclear reactor, or LMR is a type of nuclear reactor where the primary coolant is a liquid metal. Liquid metal cooled reactors were first adapted for breeder reactor power generation. They have also been used to power nuclear submarines.
The S2W reactor was a naval reactor built by Westinghouse used by the United States Navy to provide electricity generation and propulsion on warships.
The S3W reactor is a naval reactor used by the United States Navy to provide electricity generation and propulsion on warships. The S3W designation stands for:
The S6W reactor is a naval reactor used by the United States Navy to provide electricity generation and propulsion on warships. The S6W designation stands for:
The United States Navy Nuclear Propulsion community consists of Naval Officers and Enlisted members who are specially trained to run and maintain the nuclear reactors that power the submarines and aircraft carriers of the United States Navy. Operating more than 80 nuclear-powered ships, the United States Navy is currently the largest naval force in the world.
USS Hyman G. Rickover (SSN-795), is a Virginia-class nuclear-powered attack submarine of the United States Navy and the second such boat commemorating Admiral Hyman G. Rickover, pioneer of the nuclear navy. The boat's sponsor is Darleen Greenert, wife of then Chief of Naval Operations, Admiral Jonathan Greenert. Both the boat's name and her sponsor were announced by the Secretary of the Navy at a ceremony at the Washington Navy Yard on 9 January 2015. Hyman G. Rickover's christening occurred on 31 July 2021, and she was commissioned on 14 October 2023, during a ceremony at Naval Submarine Base New London, in Groton, Connecticut.
Captain John Henry Ebersole, M.D., United States Navy Medical Corps was a pioneer in submarine medicine and radiation oncology, selected by Admiral Hyman G. Rickover to serve as medical officer aboard the US Navy's first two nuclear powered submarines, the USS Nautilus and the USS Seawolf. He was the radiologist for NASA that screened the Mercury Seven astronauts for Project Mercury. Ebersole was the radiologist responsible for the x-rays taken during the autopsy of John F. Kennedy on 22 November 1963 at Bethesda Naval Medical Center.