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Nuclear marine propulsion is propulsion of a registered ship class (cargo, bulk, tanker, container, etc.) by a nuclear reactor. Naval nuclear propulsion is propulsion that specifically refers to naval warships (see Nuclear navy). Only a very few experimental civil nuclear ships have been built; the elimination of fossil fuel does not overcome the myriad technical, economic and political problems of this application of nuclear power.^[1]

Power plants

Operation of a civil or naval ship power plant is similar to land-based nuclear power reactors. A sustained nuclear reaction in the reactor produces heat that is used to boil water. The resulting steam spins a turbine. The turbine shaft may be coupled through a gearbox speed reducer to the ship's propeller, or in a turbo-electric drive system may operate a generator that supplies electric power to motors connected to the propellers.

The majority of marine reactors are of the pressurized water type, although the US and Soviet navies have designed and fielded warships powered with liquid metal cooled reactors. Marine-type reactors differ from commercial reactors in that:

marine reactors are compact but have high power density, i.e. they produce significant power in a small volume, however the total amount of power produced in a marine reactor is small (hundreds of MW_t) compared to a commercial power reactor (thousands of MW_t).
the fuel used is typically of higher enrichment; some run on low-enriched uranium (requiring frequent refuelings), others run on highly enriched uranium (greater than 20% U-235, varying to over 96% in U.S. submarines (They do not need to be refueled as often^[2] and are quieter in operation from smaller core^[3]) to between 30–40% in Russian submarines to lower levels in some others),
the fuel is not a ceramic UO₂ (uranium oxide) but a metal-zirconium alloy (circa 15% U with 93% enrichment, or more U with lower enrichment),
marine reactors are designed for long core life, enabled by the relatively high enrichment of the uranium and by incorporating a "burnable poison" in the cores which is progressively depleted as fission products and minor actinides accumulate; the two effects cancel each other out. One of the technical difficulties is the creation of a fuel which will tolerate the very large amount of radiation damage. During use, the properties of nuclear fuel change. Fuel elements may crack and fission gas bubbles may form.

The reactor, as the ship’s propulsion system energy (heat) source, is mobile, not stationary, as in a land based nuclear reactor plant. The reactor, and all of its auxiliary support equipment, must be of an exceptionally rugged design, to withstand the forces associated with the movement of a ship.

Oceanic weather, the wide variations of air and water temperature, plus the corrosive nature of the salt air and water environments, place even greater, unique design demands upon the sea-based nuclear power propulsion plant.

Finally, the marine reactor propulsion plant must be of cost effective design, construction and operation. It must be highly reliable and self sufficient, so as to be easily reparable and sustainable through repairs, conducted many thousands of miles from its home port.

Long-term integrity of the compact reactor pressure vessel is maintained by providing an internal neutron shield. (This is in contrast to early Soviet civil PWR designs where embrittlement occurs due to neutron bombardment of a very narrow pressure vessel.)

The Russian, U.S. and British navies rely on steam turbine propulsion, while the French and Chinese use the turbine to generate electricity for propulsion (turbo-electric propulsion). Most Russian submarines as well as most American aircraft carriers are powered by two reactors, an exception being the first nuclear powered aircraft carrier the USS Enterprise with eight. The majority of U.S., British, French and Chinese submarines are powered by one, with the notable exception of the USS Triton, the first submarine to circumnavigate the world submerged, with two reactors.

Decommissioning nuclear-powered submarines has become a major task for US and Russian navies. After defuelling, U.S. practice is to cut the reactor section from the vessel for disposal in shallow land burial as low-level waste (see the Ship-Submarine recycling program). In Russia, whole vessels, or sealed reactor sections, typically remain stored afloat, although a new facility near Sayda Bay is to provide storage in a concrete-floored facility on land for some submarines in the far north.

Russia is well advanced with plans to build a floating nuclear power plant for their far eastern territories. The design has two 35 MWe units based on the KLT-40 reactor used in icebreakers (with refueling every four years). Some Russian naval vessels have been used to supply electricity for domestic and industrial use in remote far eastern and Siberian towns.

Lloyd's Register is investigating the possibility of civilian nuclear marine propulsion and rewriting draft rules.^[4]

History

Military

Under the direction of Admiral Hyman G. Rickover^[5], the design, development and production of nuclear marine propulsion plants started in the USA in the 1940s, with the first test reactor being started up in 1953. The first nuclear-powered submarine, USS Nautilus, put to sea in 1955. Much of the early development work on naval reactors was done at the Naval Reactor Facility on the campus of the Idaho National Laboratory^[6].

The Soviets were also involved in the production of a nuclear submarine. They produced the November class, the first of which, K-3 "Leninskiy Komsomol", was underway under nuclear power on July 4, 1958.

The large amounts of power produced by an air-independent nuclear reactor marked the transition of submarines from slow vessels required to surface often, to warships capable of sustaining 20-25 knots (37-46 km/h) submerged for many weeks.

Nautilus led to the parallel development of further Skate-class submarines, powered by single reactors, and a cruiser, USS Long Beach, in 1961, powered by two reactors. The aircraft carrier USS Enterprise, commissioned in 1961, is powered by eight reactor units.

By 1962 the United States Navy had 26 nuclear submarines operational and 30 under construction. Nuclear power had revolutionized the Navy. The technology was shared with the United Kingdom, while French, Soviet, Indian and Chinese developments proceeded separately.

After the Skate-class vessels, reactor development proceeded and in the USA a single series of standardized designs was built by both Westinghouse and General Electric, one reactor powering each vessel. Rolls-Royce built similar units for Royal Navy submarines and then developed the design further to the PWR-2 (pressurized water reactor).

The largest nuclear submarines ever built are the 26,500 tonne Russian Typhoon class.

The most compact nuclear submarines to date ever built are the 2,700 tonne french Rubis class submarine attack submarines.

USA and France have built nuclear aircraft carrier vessels.

Civil

Development of nuclear merchant ships began in the 1950s, but has not generally been commercially successful. The US-built NS Savannah was commissioned in 1962 and decommissioned eight years later. It was a technical success, but not economically viable. The German-built Otto Hahn cargo ship and research facility sailed some 650,000 nautical miles (1,200,000 km) on 126 voyages in 10 years without any technical problems.^{[citation needed]} However, it proved too expensive to operate and was converted to diesel. The Japanese Mutsu was the third civil vessel. It was dogged by technical and political problems and was an embarrassing failure. All three vessels used reactors with low-enriched uranium fuel.

The fourth nuclear merchant ship, Sevmorput, operates successfully in the specialised environment of the Northern Sea Route. Recently there has been renewed interest in nuclear propulsion, and some proposals have been drafted. For example, the cargo coaster^[7] is a new design for a nuclear cargo ship. Using the new micro nuclear reactors, other existing cargo ships could potentially be converted to nuclear propulsion as well.

Nuclear propulsion has proven both technically and economically feasible for nuclear powered icebreakers in the Soviet Arctic. The power levels and energy required for icebreaking, coupled with refueling difficulties for other types of vessels, are significant factors. The Soviet icebreaker Lenin was the world's first nuclear-powered surface vessel and remained in service for 30 years (new reactors were fitted in 1970). It led to a series of larger icebreakers, the 23,500 ton Arktika class, launched from 1975. These vessels have two reactors and are used in deep Arctic waters. NS Arktika was the first surface vessel to reach the North Pole.

For use in shallow waters such as estuaries and rivers, shallow-draft Taymyr class icebreakers with one reactor are being built in Finland and then fitted with their nuclear steam supply system in Russia. They are built to conform with international safety standards for nuclear vessels.

Naval nuclear accidents

United States

USS Thresher (SSN-593) (1963; Thresher/Permit-class; sank, 129 killed)
USS Scorpion (SSN-589) (1968; Skipjack-class; sank, 99 killed)

Both sank for reasons unrelated to their reactor plants and still lie on the Atlantic sea floor.

Russian or Soviet

K-8 (1960; November-class submarine; loss of coolant)
K-19 (1961; Hotel-class submarine; two loss of coolant accidents, 27 killed due to one accident)
K-11 (1965; November-class submarine; two refueling criticalities)
K-159 (1965; November-class submarine; radioactive discharge)
Lenin (1965; Lenin-class icebreaker; loss of coolant)
Lenin (1967; Lenin-class icebreaker; loss of coolant)
K-140 (1968; Yankee-class submarine; power excursion)
K-8 (loss of coolant) (1970; November-class submarine; sank after fire, 52 killed)
K-320 (1970; Charlie I-class submarine; uncontrolled startup)
K-116 (1979; Echo II-class submarine; reactor accident)
K-122 (1980; Echo I-class submarine; fire, 14 killed)
K-222 (1980; Papa-class submarine; uncontrolled startup)
K-27 (1982; Modified November-class submarine; scuttled)
K-123 (1982; Alfa-class submarine; loss of coolant)
K-429 (1983; Charlie I-class submarine; sank due to improper work at shipyard, 16 killed)
K-431 (1985; Echo II-class submarine; refueling criticality, 10 killed)
K-429 (1985; Charlie I-class submarine; sank at moorings)
K-219 (1986; Yankee I-class submarine; sank after collision, 6 killed)
K-278 Komsomolets (1989; Mike class submarine; sank, 42 killed)
K-192 (1989; Echo II-class submarine; loss of coolant)
K-141 Kursk (2000; Oscar II-class submarine; sank, 118 killed)
K-159 (2003; November-class submarine; sank under tow, 9 killed)

While not all of these were reactor accidents, they have a major impact on nuclear marine propulsion and the global politics because they happened to nuclear vessels. Many of these accidents resulted in the sinking of the boat containing nuclear weapons on board, which remain there to this day.^[8]

References

^ John G. Wirt, A Federal Demonstration Project: N.S. Savannah, in Maritime Transportation Research Board , National Research Council (U.S.). Innovation in the maritime industry, Volume 1 National Academies, 1979 pp. 29-36
^ James Clay Moltz (2006). "Global Submarine Proliferation: Emerging Trends and Problems". NTI. Retrieved 2007-03-07. {{cite web}}: Unknown parameter |month= ignored (help)
^ James Acton (December 13, 2007). "Silence is highly enriched uranium". Retrieved 2007-12-13.
^ Full steam ahead for nuclear shipping World Nuclear News, 18 November 2010. Accessed: 27 November 2010.
^ Groves, Leslie R. (1983). Now it can be told. p. 388. ISBN 9780306801891. {{cite book}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)
^ Stacy, Susan (2000). Proving the Principle: A History of the Idaho National Engineering and Environmental Laboratory, 1949-1999. ISBN 9780160591853.
^ [1]
^ Database of radiological incidents and related events

AFP, 11 November 1998; in "Nuclear Submarines Provide Electricity for Siberian Town," FBIS-SOV-98-315, 11 November 1998.
ITAR-TASS, 11 November 1998; in "Russian Nuclear Subs Supply Electricity to Town in Far East," FBIS-SOV-98-316, 12 November 1998.
Harold Wilson's plan BBC News story

External links

[1] John G. Wirt, A Federal Demonstration Project: N.S. Savannah, in Maritime Transportation Research Board , National Research Council (U.S.). Innovation in the maritime industry, Volume 1 National Academies, 1979 pp. 29-36

[2] James Clay Moltz (2006). "Global Submarine Proliferation: Emerging Trends and Problems". NTI. Retrieved 2007-03-07. {{cite web}}: Unknown parameter |month= ignored (help)

[3] James Acton (December 13, 2007). "Silence is highly enriched uranium". Retrieved 2007-12-13.

[wnnLL-4] Full steam ahead for nuclear shipping World Nuclear News, 18 November 2010. Accessed: 27 November 2010.

[5] Groves, Leslie R. (1983). Now it can be told. p. 388. ISBN 9780306801891. {{cite book}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)

[6] Stacy, Susan (2000). Proving the Principle: A History of the Idaho National Engineering and Environmental Laboratory, 1949-1999. ISBN 9780160591853.

[7] [1]

[8] Database of radiological incidents and related events

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[2]

[3]

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@@ Line 1: / Line 1: @@
-'''Nuclear marine propulsion''' is propulsion of a registered ship class (cargo, bulk, tanker, container, etc.) by a [[nuclear reactor]]. '''Naval nuclear propulsion''' is propulsion that specifically refers to naval warships (see [[Nuclear navy]]).
+'''Nuclear marine propulsion''' is propulsion of a registered ship class (cargo, bulk, tanker, container, etc.) by a [[nuclear reactor]]. '''Naval nuclear propulsion''' is propulsion that specifically refers to naval warships (see [[Nuclear navy]]). Only a very few experimental civil nuclear ships have been built; the elimination of fossil fuel does not overcome the myriad technical, economic and political problems of this application of [[nuclear power]].<ref>John G. Wirt, ''A Federal Demonstration Project: N.S. Savannah'', in Maritime Transportation Research Board , National Research Council (U.S.). ''Innovation in the maritime industry, Volume 1'' National Academies, 1979 pp. 29-36 </ref>
 [[Image:Nuclear fuel element.jpg|thumb|right|A nuclear fuel element for the cargo ship [[NS Savannah|NS ''Savannah'']]. The element contains four bundles of 41 fuel rods. The uranium oxide is enriched to 4.2 and 4.6 percent of U-235]]
 ==Power plants==
+Operation of a civil or naval ship power plant is similar to land-based [[Nuclear reactor technology|nuclear power reactors]].  A sustained [[Nuclear chain reaction|nuclear reaction]] in the reactor produces heat that is used to boil water.  The resulting steam spins a [[Steam turbine|turbine]]. The turbine shaft may be coupled through a gearbox speed reducer to the ship's propeller, or in a turbo-electric drive system may operate a generator that supplies electric power to motors connected to the propellers.
 The majority of marine [[Nuclear reactor|reactors]] are of the [[Pressurized water reactor|pressurized water]] type, although the US and Soviet navies have designed and fielded warships powered with [[liquid metal cooled reactor]]s.  Marine-type reactors differ from commercial reactors in that:
@@ Line 9: / Line 12: @@
 *the fuel used is typically of higher enrichment; some run on low-enriched [[uranium]] (requiring frequent refuelings), others run on [[highly enriched uranium]] (greater than 20% U-235, varying to over 96% in U.S. [[submarine]]s (They do not need to be refueled as often<ref>{{cite web|url=http://www.nti.org/e_research/e3_74.html|title=Global Submarine Proliferation: Emerging Trends and Problems|author=James Clay Moltz|publisher=[[NTI]]|month=March | year=2006|accessdate=2007-03-07}}</ref> and are quieter in operation from smaller core<ref>{{cite web|url=http://www.armscontrolwonk.com/1738/silence-is-highly-enriched-uranium|title=Silence is highly enriched uranium|date=December 13, 2007|author=James Acton|accessdate=2007-12-13}}</ref>) to between 30–40% in Russian submarines to lower levels in some others),
 *the fuel is not a ceramic UO<sub>2</sub> (uranium oxide) but a metal-[[zirconium]] alloy (circa 15% U with 93% enrichment, or more U with lower enrichment),
-*marine reactors are designed for long core life, enabled by the relatively high enrichment of the [[uranium]] and by incorporating a "burnable [[Nuclear poison|poison]]" in the cores which is progressively depleted as [[fission product]]s and [[minor actinides]] accumulate; the two effects cancel each other out. One of the technical difficulties is the creation of a fuel which will tolerate the very large amount of radiation damage. It is known that during use the properties of [[nuclear fuel]] change; it is quite possible for fuel to [[fracture|crack]] and for [[nuclear fission|fission]] gas bubbles to form.
+*marine reactors are designed for long core life, enabled by the relatively high enrichment of the [[uranium]] and by incorporating a "burnable [[Nuclear poison|poison]]" in the cores which is progressively depleted as [[fission product]]s and [[minor actinides]] accumulate; the two effects cancel each other out. One of the technical difficulties is the creation of a fuel which will tolerate the very large amount of radiation damage. During use, the properties of [[nuclear fuel]] change. Fuel elements may  [[fracture|crack]] and [[nuclear fission|fission]] gas bubbles may form.
-*The reactor, as the ship’s propulsion system energy (heat) source, is mobile, not stationary, as in a land based nuclear reactor plant.  So the reactor, and all of its auxiliary support equipment, must be of an exceptionally rugged design, to withstand the forces (sometimes very violent forces) associated with the movement of a ship over the world's oceans.
+*The reactor, as the ship’s propulsion system energy (heat) source, is mobile, not stationary, as in a land based nuclear reactor plant.  The reactor, and all of its auxiliary support equipment, must be of an exceptionally rugged design, to withstand the forces associated with the movement of a ship.
 *Oceanic weather, the wide variations of air and water temperature, plus the corrosive nature of the salt air and water environments, place even greater, unique design demands upon the sea-based nuclear power propulsion plant.