Nuclear submarine

Nuclear submarine
USS Michigan: An Ohio-class guided missile submarine.

A nuclear submarine is a submarine powered by a nuclear reactor (see also nuclear marine propulsion). The performance advantages of nuclear submarines over "conventional" (typically diesel-electric) submarines are considerable: 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 durations; and the long interval between refuellings grants a range limited only by consumables such as food. Current generations of nuclear submarines never need to be refueled throughout their 25-year lifespans.[1] Conversely, the limited power stored in electric batteries means that even the most advanced conventional submarine can only remain submerged for a few days at slow speed, and only a few hours at top speed; recent advances in air-independent propulsion have eroded this disadvantage somewhat. The high cost of nuclear technology means that relatively few states have fielded nuclear submarines. Some of the most serious nuclear and radiation accidents in the world have involved Soviet nuclear submarine mishaps.[2][3]



USS Nautilus (SSN-571), the first nuclear powered submarine.

The idea for a nuclear-powered submarine was first proposed by the Naval Research Laboratory's Ross Gunn[4] in 1939.

The United States launched the USS Nautilus, the first nuclear submarine, in 1954.[5] Nautilus could remain underwater for up to four months without resurfacing.

Construction of the Nautilus 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 Atomic Energy Commission. In July 1951, the U.S. Congress authorized construction of the world's first nuclear-powered submarine, under the leadership of Captain Hyman G. Rickover, USN.[6]

The Westinghouse Corporation was assigned to build its reactor. After the submarine was completed, Mamie Eisenhower broke the traditional bottle of champagne on Nautilus' bow. On January 17, 1955, it began its sea trials after leaving its dock in Groton, Connecticut. The submarine was 320 feet long, and cost about $55 million.

The Soviet Union soon followed the United States in developing nuclear-powered submarines in the 1950s. Stimulated by the U.S. development of the Nautilus, Soviet work on nuclear propulsion reactors began 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 entered service in the Soviet Navy in 1958.[7]

The VMF Typhoon class submarine, is nuclear powered and the world's largest-displacement submarine.[8]

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.[9]

Today, six countries deploy some form of nuclear-powered strategic submarines: the United States, Russia, France, the United Kingdom, People's Republic of China, and India.[10] Several other countries, including Argentina and Brazil,[11][12] have ongoing projects in different phases to build nuclear-powered submarines.

In the United Kingdom, all former and current nuclear submarines for the 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 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.[note 1]


HMS Astute, an advanced nuclear powered attack submarine.[13]

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.

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 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 coupled 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" observable by thermal imaging systems, e.g. FLIR.[14]


United States United States Navy



Soviet UnionSoviet / RussiaRussian Navy


Operational submarines

Under development

United Kingdom Royal Navy of the United Kingdom



France French Navy



Under development

China People's Liberation Army Navy of the People's Republic of China


Under development

India Indian Navy


Under development

  • INS Arihant, currently undergoing sea-trials. Scheduled to be operational in 2012.


Some of the most serious nuclear and radiation accidents in the world have involved Soviet nuclear submarine mishaps.[2][3] Notable nuclear submarine accidents include:

  • K-19, 4 July 1961, the reactor almost had a meltdown and exploded, resulting in 8 deaths and more than 30 other people being over-exposed to radiation.[15] The events on board the submarine are dramatized by the film K-19: The Widowmaker.
  • USS Thresher (SSN-593), 1963, was lost during deep diving tests and later investigation concluded that failure of a brazed pipe joint and ice formation in the ballast blow valves prevented surfacing. The accident motivated a number of safety changes to the US fleet.
  • USS Scorpion (SSN-589), 1968, lost.
  • K-27, 24 May 1968, experienced a near meltdown of one of its liquid metal (lead-bismuth) cooled VT-1 reactors, resulting in 9 fatalities and 83 other injuries.[2] The ship was deactivated by 20 July 1968.
  • K-431 reactor accident on 10 August 1985 resulted in 10 fatalities and 49 other people suffered radiation injuries.[3]
  • K-219, 1986, the reactor almost had a meltdown. Sergei Preminin died after he manually lowered the control rods, and stopped the explosion. The submarine sank three days later.
  • K-278 Komsomolets, 1989, Soviet submarine sank in Barents Sea due to a fire.
  • K-141 Kursk, 2000, the generally accepted theory is that a leak of hydrogen peroxide in the forward torpedo room led to the detonation of a torpedo warhead, which in turn triggered the explosion of half a dozen other warheads about two minutes later.
  • Ehime Maru & USS Greeneville, February 2001, the American submarine surfaced underneath the Japanese training vessel. Nine Japanese were killed when their ship sank as a result of the collision.[16]
  • USS San Francisco (SSN-711), 2005, collided with a seamount in the Pacific Ocean. A crew member was killed and 23 others were injured.
  • HMS Vanguard & Le Triomphant, February 2009, the French and British submarines collided in the Atlantic while on routine patrols. There were no injuries among the crews, but both ships were damaged during the collision.

See also


  1. ^ The only other submarine to sink a warship since World War II is the Pakistani Navy's PNS Hangor.
  1. ^ Naval Technology - SSN Astute Class - Attack Submarine
  2. ^ a b c Johnston, Robert (September 23, 2007). "Deadliest radiation accidents and other events causing radiation casualties". Database of Radiological Incidents and Related Events. 
  3. ^ a b c The Worst Nuclear Disasters
  4. ^ NRL Little Book of Achievements
  5. ^ USS Nautilus (SSN-571)
  6. ^ Nuclear Propulsion
  7. ^ Submarine History 1945-2000: A Timeline of Development
  8. ^ Submarine Milestones -- Largest Subs; 1981: Typhoon Class (Soviet and Russian) National Geographic
  9. ^ CNS - Resources on Russian Nuclear Submarines
  10. ^ NTI: Submarine Proliferation
  11. ^ "Argentina, Brazil eye joint project for nuclear submarine". The Times of India. 25 February 2008. Archived from the original on 2008-03-01. Retrieved 2008-03-27. 
  12. ^ Sarah Diehl and Eduardo Fujii (March 2008). Brazil’s Pursuit of a Nuclear Submarine Raises Proliferation Concerns. WMD Insights. Retrieved 2008-03-27. 
  13. ^ "Exclusive: Royal Navy's most advanced submarine HMS Astute set for home on the River Clyde". Daily Record. 13 November 2009. Retrieved 20 November 2009. 
  14. ^ Samuel Upton Newtan Nuclear War I and Other Major Nuclear Disasters of the 20th Century p.291, AuthorHouse, 2007 ISBN 9781425985110
  15. ^ Strengthening the Safety of Radiation Sources p. 14.
  16. ^ Ehime Maru and USS Greeneville collision

Suggested Reading

External links

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