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Nuclear submarine

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Nuclear submarine

A nuclear submarine is a submarine powered by a nuclear reactor. 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 periods of time; and the long interval between refuelings 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. 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 somewhat eroded this disadvantage. The high cost of nuclear technology means that relatively few states have fielded nuclear submarines. Some of the most serious nuclear and radiation accidents ever to occur have involved Soviet nuclear submarine mishaps.


The idea for a nuclear-powered submarine was first proposed in the United States Navy by the Naval Research Laboratory's Ross Gunn in 1939.

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 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 names 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).

The Westinghouse Corporation was assigned to build its reactor. After the submarine was completed at the Electric Boat Company, Mamie Eisenhower (wife of the U.S. President) broke the traditional bottle of champagne on Nautilus' bow, and she was commissioned USS Nautilus (SSN-571), on 30 September 1954. 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.

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, 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.

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 (SSBN-598) 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, the 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".

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.

Today, six countries deploy some form of nuclear-powered strategic submarines: the United States, Russia, France, the United Kingdom, China, and India. Several other countries, including Argentina and Brazil, 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 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.


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. 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.


  • SCB-64: USS Nautilus (SSN-571)
  • SCB-64A: USS Seawolf (SSN-575)
  • SCB-121: Skate class attack submarines
  • SCB-132: USS Triton (SSRN-586)
  • SCB-137A: USS Halibut (SSGN-587)
  • SCB-154: Skipjack class attack submarines
  • SCB-178: USS Tullibee (SSN-597)
  • SCB-180A: George Washington class ballistic missile submarines
  • SCB-180: Ethan Allen class ballistic missile submarines
  • SCB-188: Permit class attack submarines
  • SCB-188A: Sturgeon class attack submarines
  • SCB-216: Lafayette class ballistic missile submarines
  • SCB-216: James Madison class ballistic missile submarines
  • SCB-216: Benjamin Franklin class ballistic missile submarines
  • NR-1
  • SCB-245: USS Narwhal (SSN-671)
  • SCB-302: USS Glenard P. Lipscomb (SSN-685)
  • Operational

  • SCB-303: Los Angeles class attack submarines
  • SCB-304: Ohio-class ballistic missile submarines
  • Seawolf class attack submarines
  • Virginia class attack submarines
  • Under development

  • Ohio replacement SSBN(X) (In development)
  • Decommissioned

  • Project 627 (November) attack submarines
  • Project 645 test attack submarine K-27
  • Project 658 (Hotel) ballistic missile submarines
  • Project 659/675 (Echo) cruise missile submarines
  • Project 661 (Papa) attack submarines
  • Project 667 (Yankee) ballistic missile submarines
  • Project 667B, Murena (Delta I) ballistic missile submarines
  • Project 667BD, Murena-M (Delta II) ballistic missile submarines
  • Project 670 (Charlie) cruise missile submarines
  • Project 671 (Victor) attack submarines
  • Project 678 (X-Ray) research submersible
  • Project 685 (Mike) Attack submarine K-278 Komsomolets
  • Project 705 (Alfa) attack submarines
  • Operational submarines

  • Project 941 (Typhoon) ballistic missile submarines
  • Project 945 (Sierra) attack submarines
  • Project 949 (Oscar) cruise missile submarines
  • Project 667BDR, Kalmar (Delta III) ballistic missile submarines
  • Project 667BDRM, Delfin (Delta IV) ballistic missile submarines
  • Project 1910 Kashalot-class (Uniform) special purpose submarines
  • Project 1851.1 (Paltus) special purpose submarines
  • AS-12 (Losharik) special purpose submarine
  • Project 971 (Akula) attack submarines
  • Project 671RTM Shchuka (Victor III) attack submarines
  • Project 935 (Borei) ballistic missile submarines
  • Project 885 (Graney) attack submarines
  • Decommissioned

  • HMS Dreadnought (S101)
  • Valiant class attack submarines
  • Resolution class ballistic missile submarines
  • Churchill class attack submarines
  • Swiftsure class attack submarines
  • Operational

  • Trafalgar class attack submarines
  • Vanguard class ballistic missile submarines
  • Astute class attack submarines
  • Under development

  • Dreadnought-class ballistic missile submarines (In development)
  • Decommissioned

  • Redoutable class ballistic missile submarines
  • Operational

  • Rubis class attack submarines
  • Triomphant class ballistic missile submarines
  • Under development

  • Barracuda class attack submarines (In development)
  • Operational

  • Type 091 (Han) attack submarines
  • Type 092 (Xia) ballistic missile submarines
  • Type 093 (Shang) attack submarines
  • Type 094 (Jin) ballistic missile submarines
  • Under development

  • Type 095 attack submarines (In development)
  • Type 096 (Tang) ballistic missile submarines (In development)
  • Decommissioned

  • INS Chakra leased Soviet Charlie-class submarine commissioned between 1987 – 1991.
  • Operational

  • INS Chakra leased Russian Akula Class attack submarine, named after the previous INS Chakra
  • Arihant-class submarine INS Arihant commissioned in August 2016 in the Indian Navy.
  • Under development

  • Arihant class submarine – INS Arihant awaiting induction, INS Aridhaman and two more boats under construction). To be followed by larger boats capable of carrying 12–16 ballistic missiles.
  • Indian Navy SSN programme6 submarines to be built. (Planned)
  • Under development

  • SNB Álvaro Alberto – SN10 attack submarines (Planned)
  • Reactor accidents

    Some of the most serious nuclear and radiation accidents by death toll in the world have involved nuclear submarine mishaps. To date, all of these were units of the former Soviet Union. Reactor accidents that resulted in core damage and release of radioactivity from nuclear-powered submarines include:

  • K-8, 1960: suffered a loss-of-coolant accident; substantial radioactivity released.
  • K-14, 1961: the reactor compartment was replaced due to unspecified "breakdown of reactor protection systems".
  • K-19, 1961: suffered a loss-of-coolant accident resulting in 8 deaths and more than 30 other people being over-exposed to radiation. The events on board the submarine are dramatized by the film K-19: The Widowmaker.
  • K-11, 1965: both reactors were damaged during refueling while lifting the reactor vessel heads; reactor compartments scuttled off the east coast of Novaya Zemlya in the Kara Sea in 1966.
  • K-27, 1968: experienced reactor core damage to one of its liquid metal (lead-bismuth) cooled VT-1 reactors, resulting in 9 fatalities and 83 other injuries; scuttled in the Kara Sea in 1982.
  • K-140, 1968: the reactor was damaged following an uncontrolled, automatic increase in power during shipyard work.
  • K-429, 1970: an uncontrolled start-up of the ship's reactor led to a fire and the release of radioactivity
  • K-116, 1970: suffered a loss-of-coolant accident in the port reactor; substantial radioactivity released.
  • K-64, 1972: the first Alfa-class liquid-metal cooled reactor failed; reactor compartment scrapped.
  • K-222, 1980: the Papa-class submarine had a reactor accident during maintenance in the shipyard while the ship's naval crew had left for lunch.
  • K-123, 1982: the Alfa-class submarine reactor core damaged by liquid-metal coolant leak; the sub was forced out of commission for eight years.
  • K-431, 1985: a reactor accident while refueling resulted in 10 fatalities and 49 other people suffered radiation injuries.
  • K-219, 1986: suffered an explosion and fire in a missile tube, eventually leading to a reactor accident; a 20-year-old enlisted seaman, Sergei Preminin, sacrificed his life to secure one of the onboard reactors. The submarine sank three days later.
  • K-192, 1989 (reclassified from K-131): suffered a loss-of-coolant accident due to a break in the starboard reactor loop.
  • Other major accidents and sinkings

  • USS Thresher (SSN-593), 1963: was lost during deep diving tests with 129 crew and shipyard personnel on board; 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 U.S. fleet. Thresher was the first of only two submarines to exceed 100 onboard deaths, joined by the Russian Kursk's 118 lost in 2000.
  • K-3, 1967: the first Soviet nuclear submarine experienced a fire associated with the hydraulic system, killing 39 sailors.
  • USS Scorpion (SSN-589), 1968: was lost at sea, evidently due to implosion upon sinking. What caused Scorpion to descend to its crush depth is not known.
  • USS Guitarro (SSN-665), 1969: sank while pier-side in shipyard due to improper ballasting. The submarine was eventually completed and commissioned.
  • K-8, 1970: a fire and a towing accident resulted in the boat's sinking and loss of all 52 crewmen remaining aboard.
  • K-56, 1973: a collision with another Soviet vessel led to flooding of the battery well and many crew deaths due to chlorine gas.
  • K-429, 1983: the sub survivably sank to the ocean bottom due to flooding from improper rig-for-dive and shipyard errors; 16 crewmen were killed.
  • K-278 Komsomolets, 1989: the Soviet submarine sank in Barents Sea due to a fire.
  • K-141 Kursk, 2000: lost at sea with all 118 crewmen on board; 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 and USS Greeneville, 2001: the American submarine surfaced underneath the Japanese training vessel. Nine Japanese were killed when their ship sank as a result of the collision.
  • K-159, 2003: sank in the Barents Sea while being towed to be scrapped, killing nine crewmen.
  • USS San Francisco (SSN-711), 2005: collided with a seamount in the Pacific Ocean. A crew member was killed and 23 others were injured.
  • USS Miami (SSN-755), 2012: the submarine's forward compartment was destroyed by an arsonist-set fire while in shipyard, causing damage with an estimated $700 million in repair costs. While repairs were initially planned upon, due to budget cuts the boat was subsequently scrapped.
  • References

    Nuclear submarine Wikipedia

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