Nuclear submarine

USS Nautilus, the first nuclear-powered submarine.

The smallest nuclear-powered submarine, the U.S. Navy's NR-1.

The idea for a nuclear-powered submarine was first proposed in the United States Navy by the Naval Research Laboratory's physicist Ross Gunn[4] in 1939. The Royal Navy began researching designs for nuclear propulsion plants in 1946.[5]

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 in the United States 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 a name with Captain Nemo's fictional submarine Nautilus in Jules Verne's Twenty Thousand Leagues Under the Sea, and another USS Nautilus (SS-168) that served with distinction in World War II).[6]

The Westinghouse Corporation was assigned to build its reactor. After the submarine was completed at the Electric Boat Company, First Lady Mamie Eisenhower broke the traditional bottle of champagne on Nautilus' bow, and the submarine was commissioned USS Nautilus (SSN-571), on 30 September 1954.[7] On 17 January 1955, she departed Groton, Connecticut, to begin sea trials. The submarine was 320 feet (98 m) long and cost about $55 million. Recognizing the utility of such vessels, the British Admiralty formed plans to build nuclear-powered submarines.[8]

The Soviet Union soon followed the United States in developing nuclear-powered submarines in the 1950s. Stimulated by the U.S. development of Nautilus, Soviets began work on nuclear propulsion reactors in the early 1950s at the Institute of Physics and Power Engineering, in Obninsk, under Anatoliy P. Alexandrov, later to become head of the Kurchatov Institute. In 1956, the first Soviet propulsion reactor designed by his team began operational testing. Meanwhile, a design team under Vladimir N. Peregudov worked on the vessel that would house the reactor. After overcoming many obstacles, including steam generation problems, radiation leaks, and other difficulties, the first nuclear submarine based on these combined efforts, K-3 Leninskiy Komsomol of the Project 627 Kit class, called a November-class submarine by NATO, entered service in the Soviet Navy in 1958.[9]

The United Kingdom's first nuclear-powered submarine HMS Dreadnought was fitted with an American S5W reactor, provided to Britain under the 1958 US-UK Mutual Defence Agreement. The hull and combat systems of Dreadnought were of British design and construction, although the hull form and construction practices were influenced by access to American designs.[5] During Dreadnought's construction, Rolls-Royce, in collaboration with the United Kingdom Atomic Energy Authority at the Admiralty Research Station, HMS Vulcan, at Dounreay, developed a completely new British nuclear propulsion system. In 1960, the UK's second nuclear-powered submarine was ordered from Vickers Armstrong and, fitted with Rolls-Royce's PWR1 nuclear plant, HMS Valiant was the first all-British nuclear submarine. Further technology transfers from the United States made Rolls-Royce entirely self-sufficient in reactor design in exchange for a "considerable amount" of information regarding submarine design and quietening techniques transferred from the United Kingdom to the United States.[10] The rafting system for the Valiant class provided the Royal Navy with an advantage in submarine silencing that the United States Navy did not introduce until considerably later.[11]

Nuclear power proved ideal for the propulsion of strategic ballistic missile submarines (SSB), greatly improving their ability to remain submerged and undetected. The world's first operational nuclear-powered ballistic missile submarine (SSBN) was USS George Washington with 16 Polaris A-1 missiles, which conducted the first SSBN deterrent patrol November 1960 – January 1961. The Soviets already had several SSBs of the Project 629 (Golf class) and were only a year behind the US with their first SSBN, ill-fated K-19 of Project 658 (Hotel class), commissioned in November 1960. However, this class carried the same three-missile armament as the Golfs. The first Soviet SSBN with 16 missiles was the Project 667A (Yankee class), the first of which entered service in 1967, by which time the US had commissioned 41 SSBNs, nicknamed the "41 for Freedom".[12][13]

The nuclear-powered VMF Typhoon-class submarine is the world's largest-displacement submarine.[14]

At the height of the Cold War, approximately five to ten nuclear submarines were being commissioned from each of the four Soviet submarine yards (Sevmash in Severodvinsk, Admiralteyskiye Verfi in St.Petersburg, Krasnoye Sormovo in Nizhny Novgorod, and Amurskiy Zavod in Komsomolsk-on-Amur). From the late 1950s through the end of 1997, the Soviet Union, and later Russia, built a total of 245 nuclear submarines, more than all other nations combined.[15]

Today, six countries deploy some form of nuclear-powered strategic submarines: the United States, Russia, the United Kingdom, France, China, and India.[16] Several other countries including Brazil and Australia[17][18] have ongoing projects in different phases to build nuclear-powered submarines.

In the United Kingdom, all former and current nuclear submarines of the British Royal Navy (with the exception of three: HMS Conqueror, HMS Renown and HMS Revenge) have been constructed in Barrow-in-Furness (at BAE Systems Submarine Solutions or its predecessor VSEL) where construction of nuclear submarines continues. Conqueror is the only nuclear-powered submarine in the world ever to have engaged an enemy ship with torpedoes, sinking the cruiser ARA General Belgrano with two Mark 8 torpedoes during the 1982 Falklands War.[lower-alpha 1]

HMS Astute, an advanced nuclear-powered attack submarine.[19]

The main difference between conventional submarines and nuclear submarines is the power generation system. Nuclear submarines employ nuclear reactors for this task. They either generate electricity that powers electric motors connected to the propeller shaft or rely on the reactor heat to produce steam that drives steam turbines (cf. nuclear marine propulsion). Reactors used in submarines typically use highly enriched fuel (often greater than 20%) to enable them to deliver a large amount of power from a smaller reactor and operate longer between refuelings – which are difficult due to the reactor's position within the submarine's pressure hull.

The nuclear reactor also supplies power to the submarine's other subsystems, such as for maintenance of air quality, fresh water production by distilling salt water from the ocean, temperature regulation, etc. All naval nuclear reactors currently in use are operated with diesel generators as a backup power system. These engines are able to provide emergency electrical power for reactor decay heat removal, as well as enough electric power to supply an emergency propulsion mechanism. Submarines may carry nuclear fuel for up to 30 years of operation. The only resource that limits the time underwater is the food supply for the crew and maintenance of the vessel.

The stealth technology weakness of nuclear submarines is the need to cool the reactor even when the submarine is not moving; about 70% of the reactor output heat is dissipated into the sea water. This leaves a "thermal wake", a plume of warm water of lower density which ascends to the sea surface and creates a "thermal scar" that is observable by thermal imaging systems, e.g., FLIR.[20] Another problem is that the reactor is always running, creating steam noise, which can be heard on sonar, and the reactor pump (used to circulate reactor coolant), also creates noise, as opposed to a conventional submarine, which can move about on almost silent electric motors.

• Ballistic missile submarine – Submarine that can launch ballistic missiles
• Attack submarine – Submarine designed to destroy other ships
• List of nuclear submarines
• Nuclear-powered icebreaker – Ship capable of navigating through waters covered with ice
• Nuclear marine propulsion – Propulsion system for marine vessels utilizing a nuclear powerplant
• SSN (hull classification symbol) – Symbol for nuclear-powered general-purpose attack submarine
• Submarine – Watercraft capable of independent operation underwater
• History of submarines – Aspect of history
• List of lost United States submarines

• Friedman, Norman (1984). Submarine design and development. Conway Maritime. ISBN 0-87021-954-5.
• Friedman, Norman (1994). U.S. submarines since 1945: an illustrated design history. Naval Institute Press. ISBN 1-55750-260-9.

• Erickson, Andrew Erickson; Lyle Goldstein (Winter 2007). "China's Future Nuclear Submarine Force: Insights from Chinese Writings" (PDF). Naval War College Review. 60 (1): 54–79. Retrieved 25 August 2009.
• Offley, Edward "Ed" (2007). Scorpion Down (Hardcover ed.). New York: Basic Books by Perseus Press. ISBN 978-0-465-05185-4.
• Polmar, Norman & Moore, J.K. (2004). Cold War Submarines: The Design and Construction of U.S. and Soviet Submarines (Paperback ed.). Washington, DC: Potomac Books, Inc. ISBN 1-57488-530-8.

Wikimedia Commons has media related to Nuclear submarines.

• Nuclear Propulsion – Federation of American Scientists
• 60 Years of Marine Nuclear Power: 1955 - 2015 – on The Lyncean Group of San Diego web site
• V.M. Bukhalov – Atomic-powered submarine design
• Fast Attacks and Boomers: Submarines in the Cold War An online exhibition from the National Museum of American History, Smithsonian Institution
• On Eternal Patrol, website listing all US submarines and submariners lost on duty