Nuclear marine propulsion is propulsion of a ship or submarine with heat provided by a

nuclear reactor A nuclear reactor is a device used to initiate and control a Nuclear fission, fission nuclear chain reaction. They are used for Nuclear power, commercial electricity, nuclear marine propulsion, marine propulsion, Weapons-grade plutonium, weapons ...

. The power plant heats water to produce steam for a turbine used to turn the ship's

propeller A propeller (often called a screw if on a ship or an airscrew if on an aircraft) is a device with a rotating hub and radiating blades that are set at a pitch to form a helical spiral which, when rotated, exerts linear thrust upon a working flu ...

through a

gearbox A transmission (also called a gearbox) is a mechanical device invented by Louis Renault (who founded Renault) which uses a gear set—two or more gears working together—to change the speed, direction of rotation, or torque multiplication/r ...

or through an electric generator and motor. Nuclear propulsion is used primarily within naval warships such as

nuclear submarines A nuclear submarine is a submarine powered by a nuclear reactor, but not necessarily nuclear weapons, nuclear-armed. Nuclear submarines have considerable performance advantages over "conventional" (typically Marine diesel engine, diesel-elect ...

and

supercarrier An aircraft carrier is a warship that serves as a seagoing airbase, equipped with a full-length flight deck and hangar facilities for supporting, arming, deploying and recovering shipborne aircraft. Typically it is the capital ship of a ...

s. A small number of experimental civil nuclear ships have been built. Compared to oil- or coal-fuelled ships, nuclear propulsion offers the advantage of very long intervals of operation before refueling. All the fuel is contained within the nuclear reactor, so no cargo or supplies space is taken up by fuel, nor is space taken up by exhaust stacks or combustion air intakes. The low fuel cost is offset by high operating costs and investment in infrastructure, however, so nearly all nuclear-powered vessels are military.

Power plants

Basic operation of naval ship or submarine

Most naval nuclear reactors are of the pressurized water type, with the exception of a few attempts at using liquid sodium-cooled reactors. A primary water circuit transfers heat generated from

nuclear fission Nuclear fission is a reaction in which the nucleus of an atom splits into two or more smaller nuclei. The fission process often produces gamma photons, and releases a very large amount of energy even by the energetic standards of radioactiv ...

in the fuel to a

steam generator Steam is water vapor, often mixed with air or an aerosol of liquid water droplets. This may occur due to evaporation or due to boiling, where heat is applied until water reaches the enthalpy of vaporization. Saturated or superheated steam is inv ...

; this water is kept under pressure so it does not boil. This circuit operates at a temperature of around . Any

radioactive contamination Radioactive contamination, also called radiological pollution, is the deposition of, or presence of Radioactive decay, radioactive substances on surfaces or within solids, liquids, or gases (including the human body), where their presence is uni ...

in the primary water is confined. Water is circulated by pumps; at lower power levels, reactors designed for submarines may rely on natural circulation of the water to reduce noise generated by the pumps. The hot water from the reactor heats a separate water circuit in the steam generator. That water is converted to steam and passes through steam driers on its way to the

steam turbine A steam turbine or steam turbine engine is a machine or heat engine that extracts thermal energy from pressurized steam and uses it to do mechanical work utilising a rotating output shaft. Its modern manifestation was invented by Sir Charles Par ...

. Spent steam at low pressure runs through a condenser cooled by seawater and returns to liquid form. The water is pumped back to the steam generator and continues the cycle. Any water lost in the process can be made up by desalinated sea water added to the steam generator feed water. In the turbine, the steam expands and reduces its pressure as it imparts energy to the rotating blades of the turbine. There may be many stages of rotating blades and fixed guide vanes. The output shaft of the turbine may be connected to a gearbox to reduce rotation speed, then a shaft connects to the vessel's propellers. In another form of drive system, the turbine turns an electrical generator, and the electric power produced is fed to one or more drive motors for the vessel's propellers. The

Russian Russian(s) may refer to: *Russians (), an ethnic group of the East Slavic peoples, primarily living in Russia and neighboring countries *A citizen of Russia *Russian language, the most widely spoken of the Slavic languages *''The Russians'', a b ...

U.S. The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 states and a federal capital district, Washington, D.C. The 48 contiguous ...

and

British British may refer to: Peoples, culture, and language * British people, nationals or natives of the United Kingdom, British Overseas Territories and Crown Dependencies. * British national identity, the characteristics of British people and culture ...

navies rely on direct steam turbine propulsion, while French and Chinese ships use the turbine to generate electricity for propulsion ( turbo-electric transmission). Some nuclear submarines have a single reactor, but Russian submarines have two, and so had . Most American aircraft carriers are powered by two reactors, but had eight. The majority of marine reactors are of the pressurized water type, although the U.S. and Soviet navies have designed warships powered with

liquid metal cooled reactor A liquid metal cooled nuclear reactor (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 ...

Differences from land power plants

Marine-type reactors differ from land-based commercial electric power reactors in several respects. While land-based reactors in nuclear power plants produce up to around 1600 megawatts of net electrical power (the

nameplate capacity Nameplate capacity, also known as the rated capacity, nominal capacity, installed capacity, maximum effect or gross capacity,EPR), a typical marine propulsion reactor produces no more than a few hundred megawatts. Some

small modular reactor The small modular reactor (SMR) is a class of small nuclear fission reactor, designed to be built in a factory, shipped to operational sites for installation, and then used to power buildings or other commercial operations. The term SMR refers t ...

s (SMR) are similar to marine propulsion reactors in capacity and some design considerations and thus nuclear marine propulsion (whether civilian or military) is sometimes proposed as an additional market niche for SMRs. Unlike for land-based applications where hundreds of hectares can be occupied by installations like

Bruce Nuclear Generating Station Bruce Nuclear Generating Station is a nuclear power station located on the eastern shore of Lake Huron in Ontario, Canada. It occupies 932 ha (2300 acres) of land. The facility derives its name from Bruce Township, Ontario, Bruce Township, the ...

, at sea tight space limits dictate that a marine reactor must be physically small, so it must generate higher power per unit of space. This means its components are subject to greater stresses than those of a land-based reactor. Its mechanical systems must operate flawlessly under the adverse conditions encountered at sea, including vibration and the pitching and rolling of a ship operating in rough seas. Reactor shutdown mechanisms cannot rely on gravity to drop control rods into place as in a land-based reactor that always remains upright. Salt water corrosion is an additional problem that complicates maintenance. Nuclear fuel element

As the core of a seagoing reactor is much smaller than a power reactor, the probability of a neutron intersecting with a fissionable nucleus before it escapes into the shielding is much lower. As such, the fuel is typically more highly enriched (i.e., contains a higher concentration of ²³⁵U vs. ²³⁸U) than that used in a land-based nuclear power plant, which increases the probability of fission to the level where a sustained reaction can occur. Some marine reactors run on relatively low-enriched

uranium Uranium is a chemical element; it has chemical symbol, symbol U and atomic number 92. It is a silvery-grey metal in the actinide series of the periodic table. A uranium atom has 92 protons and 92 electrons, of which 6 are valence electrons. Ura ...

, which requires more frequent refueling. Others run on

highly enriched uranium Enriched uranium is a type of uranium in which the percent composition of uranium-235 (written 235U) has been increased through the process of isotope separation. Naturally occurring uranium is composed of three major isotopes: uranium-238 (238 ...

, varying from 20% ²³⁵U, to the over 96% ²³⁵U found in U.S.

submarine A submarine (often shortened to sub) is a watercraft capable of independent operation underwater. (It differs from a submersible, which has more limited underwater capability.) The term "submarine" is also sometimes used historically or infor ...

s, in which the resulting smaller core is quieter in operation (a big advantage to a submarine). Using more-highly enriched fuel also increases the reactor's power density and extends the usable life of the nuclear fuel load, but is more expensive and a greater risk to

nuclear proliferation Nuclear proliferation is the spread of nuclear weapons to additional countries, particularly those not recognized as List of states with nuclear weapons, nuclear-weapon states by the Treaty on the Non-Proliferation of Nuclear Weapons, commonl ...

than less-highly enriched fuel. A marine nuclear propulsion plant must be designed to be highly reliable and self-sufficient, requiring minimal maintenance and repairs, which might have to be undertaken many thousands of miles from its home port. One of the technical difficulties in designing fuel elements for a seagoing nuclear reactor is the creation of fuel elements that will withstand a large amount of radiation damage. Fuel elements may crack over time and gas bubbles may form. The fuel used in marine reactors is a metal-

zirconium Zirconium is a chemical element; it has Symbol (chemistry), symbol Zr and atomic number 40. First identified in 1789, isolated in impure form in 1824, and manufactured at scale by 1925, pure zirconium is a lustrous transition metal with a greyis ...

alloy rather than the ceramic UO₂ (

uranium dioxide Uranium dioxide or uranium(IV) oxide (), also known as urania or uranous oxide, is an oxide of uranium, and is a black, radioactive, crystalline powder that naturally occurs in the mineral uraninite. It is used in nuclear fuel rods in nuclear reac ...

) often used in land-based reactors. 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 fuel elements, which is slowly depleted as the fuel elements age and become less reactive. The gradual dissipation of the "nuclear poison" increases the reactivity of the core to compensate for the lessening reactivity of the aging fuel elements, thereby extending the usable life of the fuel. The compact

reactor pressure vessel A reactor pressure vessel (RPV) in a nuclear power plant is the pressure vessel containing the nuclear reactor coolant, core shroud, and the reactor core. Classification of nuclear power reactors Russian Soviet era RBMK reactors have each fu ...

is provided with an internal

neutron The neutron is a subatomic particle, symbol or , that has no electric charge, and a mass slightly greater than that of a proton. The Discovery of the neutron, neutron was discovered by James Chadwick in 1932, leading to the discovery of nucle ...

shield, which reduces the damage to the steel from constant neutron bombardment.

Decommissioning

Decommissioning nuclear-powered submarines has become a major task for U.S. 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 The Ship-Submarine Recycling Program (SRP) is the process that the United States Navy uses to dispose of Nuclear decommissioning, decommissioned nuclear navy, nuclear vessels. SRP takes place only at the Puget Sound Naval Shipyard (PSNS) in Bremer ...

''). 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.

Future designs

Russia built a floating nuclear power plant for its far eastern territories. The design has two 35 MWe units based on the KLT-40 reactor used in

icebreaker An icebreaker is a special-purpose ship or boat designed to move and navigate through ice-covered waters, and provide safe waterways for other boats and ships. Although the term usually refers to ice-breaking ships, it may also refer to smaller ...

s (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. In 2010,

Lloyd's Register Lloyd's Register Group Limited, trading as Lloyd's Register (LR), is a technical and professional services organisation and a maritime classification society, wholly owned by the Lloyd’s Register Foundation, a UK charity dedicated to research ...

was investigating the possibility of civilian nuclear marine propulsion and rewriting draft rules (see text under ''Merchant Ships'')..

Civil liability

Insurance of nuclear vessels is not like the insurance of conventional ships. The consequences of an accident could span national boundaries, and the magnitude of possible damage is beyond the capacity of private insurers. A special international agreement, the ''Brussels Convention on the Liability of Operators of Nuclear Ships'', developed in 1962, would have made signatory national governments liable for accidents caused by nuclear vessels under their flag but was never ratified owing to disagreement on the inclusion of warships under the convention. Nuclear reactors under United States jurisdiction are insured by the provisions of the Price–Anderson Act.

Military nuclear ships

By 1990, there were more nuclear reactors powering ships (mostly military) than there were generating electric power in commercial power plants worldwide. Under the direction of U.S. Navy Captain (later Admiral) Hyman G. Rickover, the design, development and production of nuclear marine propulsion plants started in the

United States The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 ...

in the 1940s. The first prototype naval reactor was constructed and tested at the

Naval Reactor Facility The Naval Reactors Facility (NRF) is located northwest of Idaho Falls, Idaho. The NRF is a United States Department of Energy-Naval Reactors facility where three nuclear propulsion prototypes A1W reactor, A1W, S1W reactor, S1W and S5G reactor, S5 ...

at the National Reactor Testing Station in Idaho (now called the

Idaho National Laboratory Idaho National Laboratory (INL) is one of the national laboratories of the United States Department of Energy and is managed by the Battelle Energy Alliance. Historically, the lab has been involved with nuclear research, although the labora ...

) in 1953.

Submarines

The first

nuclear submarine A nuclear submarine is a submarine powered by a nuclear reactor, but not necessarily nuclear-armed. Nuclear submarines have considerable performance advantages over "conventional" (typically diesel-electric) submarines. Nuclear propulsion ...

, , put to sea in 1955 (SS was a traditional

hull classification symbol The United States Navy, United States Coast Guard, and United States National Oceanic and Atmospheric Administration (NOAA) use a hull classification symbol (sometimes called hull code or hull number) to identify their ships by type and by ind ...

for U.S. submarines, while SSN denoted the first "nuclear" submarine). The Soviet Union also developed nuclear submarines. The first types developed were the Project 627, NATO-designated with two water-cooled reactors, the first of which, K-3 ''Leninsky Komsomol'', was underway under nuclear power in 1958. Nuclear power revolutionized the submarine, finally making it a true "underwater" vessel, rather than a "submersible" craft, which could only stay underwater for limited periods. It gave the submarine the ability to operate submerged at high speeds, comparable to those of surface vessels, for unlimited periods, dependent only on the endurance of its crew. To demonstrate this was the first vessel to execute a submerged

circumnavigation Circumnavigation is the complete navigation around an entire island, continent, or astronomical object, astronomical body (e.g. a planet or natural satellite, moon). This article focuses on the circumnavigation of Earth. The first circumnaviga ...

of the Earth (

Operation Sandblast Operation Sandblast was the code name for the first submarine circumnavigation of the world. It was executed by the United States Navy nuclear-powered submarine, nuclear-powered radar picket submarine in 1960 under the command of Captain Edward ...

), doing so in 1960. ''Nautilus'', with a

pressurized water reactor 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 (with notable exceptions being the UK, Japan, India and Canada). In a PWR, water is used both as ...

(PWR), led to the parallel development of other submarines like a unique liquid metal cooled (sodium) reactor in , or two reactors in ''Triton'', and then the s, powered by single reactors, and a cruiser, , in 1961, powered by two reactors. By 1962, the

United States Navy The United States Navy (USN) is the naval warfare, maritime military branch, service branch of the United States Department of Defense. It is the world's most powerful navy with the largest Displacement (ship), displacement, at 4.5 millio ...

had 26 operational nuclear submarines and another 30 under construction. Nuclear power had revolutionized the Navy. The United States shared its technology with the

United Kingdom The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a country in Northwestern Europe, off the coast of European mainland, the continental mainland. It comprises England, Scotlan ...

, while French,

Soviet The Union of Soviet Socialist Republics. (USSR), commonly known as the Soviet Union, was a List of former transcontinental countries#Since 1700, transcontinental country that spanned much of Eurasia from 1922 until Dissolution of the Soviet ...

India India, officially the Republic of India, is a country in South Asia. It is the List of countries and dependencies by area, seventh-largest country by area; the List of countries by population (United Nations), most populous country since ...

n and Chinese development proceeded separately. After the ''Skate''-class vessels, U.S. submarines were powered by a series of standardized, single-reactor designs built by Westinghouse and

General Electric General Electric Company (GE) was an American Multinational corporation, multinational Conglomerate (company), conglomerate founded in 1892, incorporated in the New York (state), state of New York and headquartered in Boston. Over the year ...

Rolls-Royce plc Rolls-Royce Holdings plc is a British multinational aerospace and defence company incorporated in February 2011. The company owns Rolls-Royce, a business established in 1904 which today designs, manufactures and distributes power systems for ...

built similar units for

Royal Navy The Royal Navy (RN) is the naval warfare force of the United Kingdom. It is a component of His Majesty's Naval Service, and its officers hold their commissions from the King of the United Kingdom, King. Although warships were used by Kingdom ...

submarines, eventually developing a modified version of their own, the PWR2. The largest nuclear submarines ever built are the 26,500 tonne Russian . The smallest nuclear warships to date are the 2,700 tonne French attack submarines. The U.S. Navy operated an unarmed nuclear submarine, the NR-1 Deep Submergence Craft, between 1969 and 2008, which was not a combat vessel but was the smallest nuclear-powered submarine at 400 tons.

Aircraft carriers

The United States and France have built nuclear

aircraft carrier An aircraft carrier is a warship that serves as a seagoing airbase, equipped with a full-length flight deck and hangar facilities for supporting, arming, deploying and recovering carrier-based aircraft, shipborne aircraft. Typically it is the ...

French Navy

The sole French nuclear

example is , commissioned in 2001 (a successor is planned). The French carrier is equipped with catapults and arresters. The has 42,000 tonnes, is the

flagship A flagship is a vessel used by the commanding officer of a group of navy, naval ships, characteristically a flag officer entitled by custom to fly a distinguishing flag. Used more loosely, it is the lead ship in a fleet of vessels, typically ...

of the French Navy (Marine Nationale). The ship carries a complement of Dassault Rafale M and E‑2C Hawkeye aircraft, EC725 Caracal and AS532 Cougar helicopters for

combat search and rescue Combat search and rescue (CSAR) are search and rescue operations that are carried out during war that are within or near combat zones. A CSAR mission may be carried out by a task force of helicopters, ground-attack aircraft, aerial refueling ta ...

, as well as modern electronics and Aster missiles.

United States Navy

The United States Navy operates 11 carriers, all nuclear-powered: *: in service 1962–2012, powered by eight reactor units, is still the only aircraft carrier to house more than two nuclear reactors, with each A2W reactor taking the place of one of the conventional boilers in earlier constructions. *: ten 101,000-ton, 1,092 ft long fleet carriers, the first of which was commissioned in 1975. A ''Nimitz''-class carrier is powered by two

s providing steam to four

s. *, one 110,000-ton, 1,106 ft long fleet carrier. The lead of the class , came into service in 2017, with another nine planned.

Destroyers and cruisers

Russian Navy

The ''Kirov'' class, Soviet designation 'Project 1144 Orlan' (

sea eagle A sea eagle or fish eagle (also called erne or ern, mostly in reference to the white-tailed eagle) is any of the birds of prey in the subfamily Haliaeetinae of the bird of prey family Accipitridae. Ten extant species exist, currently described w ...

), is a class of

nuclear-powered Nuclear power is the use of nuclear reactions to produce electricity. Nuclear power can be obtained from nuclear fission, nuclear decay and nuclear fusion reactions. Presently, the vast majority of electricity from nuclear power is produced b ...

guided-missile cruisers of the

Soviet Navy The Soviet Navy was the naval warfare Military, uniform service branch of the Soviet Armed Forces. Often referred to as the Red Fleet, the Soviet Navy made up a large part of the Soviet Union's strategic planning in the event of a conflict with t ...

and

Russian Navy The Russian Navy is the Navy, naval arm of the Russian Armed Forces. It has existed in various forms since 1696. Its present iteration was formed in January 1992 when it succeeded the Navy of the Commonwealth of Independent States (which had i ...

, the largest and heaviest

surface combatant Surface combatants (or surface ships or surface vessels) are a subset of naval warships which are designed for naval warfare, warfare on the surface of the water, with their own weapons and armed forces. They are generally ships built to fight oth ...

warships (i.e. not an

amphibious assault ship An amphibious assault ship is a type of warship employed to land and support ground forces on enemy territory during an armed conflict. The design evolved from aircraft carriers converted for use as helicopter carriers (which, as a result, ar ...

) in operation in the world. Among modern warships, they are second in size only to large

aircraft carriers An aircraft carrier is a warship that serves as a seagoing airbase, equipped with a full-length flight deck and hangar facilities for supporting, arming, deploying and recovering shipborne aircraft. Typically it is the capital ship of a fl ...

, and of similar size to

World War II World War II or the Second World War (1 September 1939 – 2 September 1945) was a World war, global conflict between two coalitions: the Allies of World War II, Allies and the Axis powers. World War II by country, Nearly all of the wo ...

era

battleship A battleship is a large, heavily naval armour, armored warship with a main battery consisting of large naval gun, guns, designed to serve as a capital ship. From their advent in the late 1880s, battleships were among the largest and most form ...

s. The Soviet classification of the ship-type is "heavy nuclear-powered guided missile cruiser" (). The ships are often referred to as

battlecruiser The battlecruiser (also written as battle cruiser or battle-cruiser) was a type of capital ship of the first half of the 20th century. These were similar in displacement, armament and cost to battleships, but differed in form and balance of att ...

s by Western defence commentators due to their size and general appearance.

United States Navy

The

at one time had

cruisers as part of its fleet. The first such ship was USS ''Long Beach'' (CGN-9). Commissioned in 1961, she was the world's first nuclear-powered

. She was followed a year later by USS ''Bainbridge'' (DLGN-25). While ''Long Beach'' was designed and built as a cruiser, ''Bainbridge'' began life as a

frigate A frigate () is a type of warship. In different eras, the roles and capabilities of ships classified as frigates have varied. The name frigate in the 17th to early 18th centuries was given to any full-rigged ship built for speed and maneuvera ...

, though at that time the Navy was using the

hull code The United States Navy, United States Coast Guard, and United States National Oceanic and Atmospheric Administration (NOAA) use a hull classification symbol (sometimes called hull code or hull number) to identify their ships by type and by in ...

"DLGN" for "

destroyer leader Destroyer leader (DL) was the United States Navy designation for large destroyers from 9 February 1951 through the early years of the Cold War. United States ships with hull classification symbol DL were officially frigates from 1 January 1955Blac ...

guided missile A missile is an airborne ranged weapon capable of Propulsion, self-propelled flight aided usually by a propellant, jet engine or rocket motor. Historically, 'missile' referred to any projectile that is thrown, shot or propelled towards a targ ...

nuclear Nuclear may refer to: Physics Relating to the nucleus of the atom: *Nuclear engineering *Nuclear physics *Nuclear power *Nuclear reactor *Nuclear weapon *Nuclear medicine *Radiation therapy *Nuclear warfare Mathematics * Nuclear space *Nuclear ...

". The last nuclear-powered cruisers the Americans would produce would be the four-ship . was commissioned in 1976, followed by in 1977, in 1978 and finally in 1980. Ultimately, all these ships proved to be too costly to maintain and they were all retired between 1993 and 1999.

Other military ships

Communication and command ships

''SSV-33 Ural'' (''ССВ-33 Урал'';

NATO reporting name NATO uses a system of code names, called reporting names, to denote military aircraft and other equipment used by post-Soviet states, former Warsaw Pact countries, China, and other countries. The system assists military communications by providi ...

: ''Kapusta''

for "cabbage"]) was a command and control naval ship operated by the

. ''SSV-33''s hull was derived from that of the

nuclear-power Nuclear power is the use of nuclear reactions to produce electricity. Nuclear power can be obtained from nuclear fission, nuclear decay and nuclear fusion reactions. Presently, the vast majority of electricity from nuclear power is produced by ...

ed s with nuclear marine propulsion. ''SSV-33'' served in

electronic intelligence Signals intelligence (SIGINT) is the act and field of intelligence-gathering by interception of ''signals'', whether communications between people (communications intelligence—abbreviated to COMINT) or from electronic signals not directly u ...

, missile tracking, space tracking, and communications relay roles. Due to high operating costs, ''SSV-33'' was laid up. ''SSV-33'' carried only light defensive weapons. These were two AK-176 76 mm guns, four AK-630 30 mm guns, and four quadruple Igla missile mounts.

Nuclear-powered UUV

The Poseidon (, "

Poseidon Poseidon (; ) is one of the twelve Olympians in ancient Greek religion and mythology, presiding over the sea, storms, earthquakes and horses.Burkert 1985pp. 136–139 He was the protector of seafarers and the guardian of many Hellenic cit ...

Kanyon), previously known by Russian codename Status-6 (), is a nuclear-powered and nuclear-armed

unmanned underwater vehicle Unmanned underwater vehicles (UUV), also known as underwater drones, are submersible vehicles that can operate underwater without a human occupant. These vehicles may be divided into two categories: remotely operated underwater vehicles (ROUVs) an ...

under development by

Rubin Design Bureau Rubin Central Design Bureau for Marine Engineering (), abbreviated as TsKB "Rubin" (), located in Saint-Petersburg, Saint Petersburg, is the largest of Russia's three main centers of submarine design, the other two being Malakhit Marine Engineerin ...

, capable of delivering both conventional and nuclear payloads. According to Russian state TV, it is able to deliver a

thermonuclear Nuclear fusion is a reaction in which two or more atomic nuclei combine to form a larger nuclei, nuclei/neutron by-products. The difference in mass between the reactants and products is manifested as either the release or absorption of ener ...

cobalt bomb of up to 200

megatonne The tonne ( or ; symbol: t) is a unit of mass equal to 1,000 kilograms. It is a non-SI unit accepted for use with SI. It is also referred to as a metric ton in the United States to distinguish it from the non-metric units of the shor ...

s (four times as powerful as the most powerful device ever detonated, the

Tsar Bomba The Tsar Bomba (code name: ''Ivan'' or ''Vanya''), also known by the alphanumerical designation "AN602", was a Thermonuclear weapon, thermonuclear aerial bomb, and by far the most powerful nuclear weapon ever created and tested. The Soviet phy ...

, and twice its maximum theoretical yield) against an enemy's naval ports and coastal cities.

Civilian nuclear ships

The following are

ship A ship is a large watercraft, vessel that travels the world's oceans and other Waterway, navigable waterways, carrying cargo or passengers, or in support of specialized missions, such as defense, research and fishing. Ships are generally disti ...

s that are or were in commercial or civilian use and have nuclear marine propulsion.

Merchant ships

Nuclear-powered civil merchant ships have not developed beyond a few experimental ships. The U.S.-built , completed in 1962, was primarily a demonstration of civil nuclear power and was too small and expensive to operate economically as a merchant ship. The design was too much of a compromise, being neither an efficient freighter nor a viable passenger liner. The German-built , completed in 1968, a cargo ship and research facility, sailed some on 126 voyages over 10 years without any technical problems. It proved too expensive to operate and was converted to diesel. The Japanese , completed in 1972, was dogged by technical and political problems. Its reactor had significant radiation leakage and fishermen protested against the vessel's operation. All of these three ships used low-enriched uranium. '' Sevmorput'', a Soviet and later Russian LASH carrier with icebreaking capability, has operated successfully on the

Northern Sea Route The Northern Sea Route (NSR) (, shortened to Севморпуть, ''Sevmorput'') is a shipping route about long. The Northern Sea Route (NSR) is the shortest shipping route between the western part of Eurasia and the Asia-Pacific region. Ad ...

since it was commissioned in 1988. , it is the only nuclear-powered merchant ship in service. Civilian nuclear ships suffer from the costs of specialized infrastructure. The ''Savannah'' was expensive to operate since it was the only vessel using its specialized nuclear shore staff and servicing facility. A larger fleet could share fixed costs among more operating vessels, reducing operating costs. Despite this, there is still interest in nuclear propulsion. In November 2010 British Maritime Technology and Lloyd's Register embarked upon a two-year study with U.S.-based Hyperion Power Generation (now Gen4 Energy), and the Greek ship operator Enterprises Shipping and Trading SA to investigate the practical maritime applications for small modular reactors. The research intended to produce a concept tanker-ship design, based on a 70 MWt reactor such as Hyperion's. In response to its members' interest in nuclear propulsion, Lloyd's Register has also re-written its 'rules' for nuclear ships, which concern the integration of a reactor certified by a land-based regulator with the rest of the ship. The overall rationale of the rule-making process assumes that in contrast to the current marine industry practice where the designer/builder typically demonstrates compliance with regulatory requirements, in the future the nuclear regulators will wish to ensure that it is the operator of the nuclear plant that demonstrates safety in operation, in addition to the safety through design and construction. Nuclear ships are currently the responsibility of their own countries, but none are involved in international trade. As a result of this work in 2014 two papers on commercial nuclear marine propulsion were published by Lloyd's Register and the other members of this consortium. These publications review past and recent work in the area of marine nuclear propulsion and describe a preliminary concept design study for a Suezmax tanker that is based on a conventional hull form with alternative arrangements for accommodating a 70 MWt nuclear propulsion plant delivering up to 23.5 MW shaft power at maximum continuous rating (average: 9.75 MW). The Gen4Energy power module is considered. This is a small fast-neutron reactor using lead–bismuth eutectic cooling and able to operate for ten full-power years before refueling, and in service last for a 25-year operational life of the vessel. They conclude that the concept is feasible, but further maturity of nuclear technology and the development and harmonisation of the regulatory framework would be necessary before the concept would be viable. Nuclear propulsion has been proposed again on the wave of decarbonization of marine shipping, which accounts for 3–4% of global greenhouse gas emissions.

Merchant cargo ships

* USNS ''American Explorer''; United States tanker, converted to conventional power while under construction * , Japan (1970–1992); never carried commercial cargo, rebuilt as diesel engine powered ''RV Mirai'' in 1996 * , Germany (1968–1979); re-powered with diesel engine in 1979 * , United States (1962–1972) * '' Sevmorput'', Russia (1988–present), ice-strengthened nuclear-powered lighter aboard ship (LASH) carrier In December 2023, the

Jiangnan Shipyard Jiangnan Shipyard ( zh, c=江南造船厂, p=Jiāngnán Zàochuán Chǎng) is a historic shipyard in Shanghai, China. The shipyard has been state-owned since its founding in 1865 and is now operated as Jiangnan Shipyard (Group) Co. Ltd. Befo ...

under the

China State Shipbuilding Corporation The China State Shipbuilding Corporation (CSSC) is a state-owned shipbuilding conglomerate of the People's Republic of China (PRC). Background CSSC is one of the top 10 defence groups in the PRC. It consists of various shipyards, equip ...

officially released a design of a 24000 TEU-class

container ship A container ship (also called boxship or spelled containership) is a cargo ship that carries all of its load in truck-size intermodal containers, in a technique called containerization. Container ships are a common means of commercial intermodal ...

— known as the KUN-24AP — at Marintec China 2023, a premier maritime industry exhibition held in

Shanghai Shanghai, Shanghainese: , Standard Chinese pronunciation: is a direct-administered municipality and the most populous urban area in China. The city is located on the Chinese shoreline on the southern estuary of the Yangtze River, with the ...

. The container ship is reported to be powered by a thorium-based

molten salt reactor A molten-salt reactor (MSR) is a class of nuclear fission reactor in which the primary nuclear reactor coolant and/or the fuel is a mixture of molten salt with a fissile material. Two research MSRs operated in the United States in the mid-20th ...

, making it a first thorium-powered container ship and, if completed, the largest nuclear-powered container ship in the world.

Icebreakers

Nuclear propulsion has proven both technically and economically feasible for

nuclear-powered icebreaker A nuclear-powered icebreaker is an icebreaker with an Nuclear marine propulsion, onboard nuclear power plant that produces power for the vessel's propulsion system. Although more expensive to operate, nuclear-powered icebreakers provide a number ...

s in the

, and later

Arctic The Arctic (; . ) is the polar regions of Earth, polar region of Earth that surrounds the North Pole, lying within the Arctic Circle. The Arctic region, from the IERS Reference Meridian travelling east, consists of parts of northern Norway ( ...

. Nuclear-fuelled ships operate for years without refueling, and the vessels have powerful engines, well-suited to the task of icebreaking. The Soviet icebreaker ''Lenin'' was the world's first nuclear-powered surface vessel in 1959 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 Ton is any of several units of measure of mass, volume or force. It has a long history and has acquired several meanings and uses. As a unit of mass, ''ton'' can mean: * the '' long ton'', which is * the ''tonne'', also called the ''metric ...

of six vessels, launched beginning in 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 The North Pole, also known as the Geographic North Pole or Terrestrial North Pole, is the point in the Northern Hemisphere where the Earth's rotation, Earth's axis of rotation meets its surface. It is called the True North Pole to distingu ...

. For use in shallow waters such as estuaries and rivers, shallow-draft, ''Taymyr''-class icebreakers were built in

Finland Finland, officially the Republic of Finland, is a Nordic country in Northern Europe. It borders Sweden to the northwest, Norway to the north, and Russia to the east, with the Gulf of Bothnia to the west and the Gulf of Finland to the south, ...

and then fitted with their single-reactor nuclear propulsion system in

Russia Russia, or the Russian Federation, is a country spanning Eastern Europe and North Asia. It is the list of countries and dependencies by area, largest country in the world, and extends across Time in Russia, eleven time zones, sharing Borders ...

. They were built to conform to international safety standards for nuclear vessels. All nuclear-powered icebreakers have been commissioned by the Soviet Union or Russia. * (1959–1989; museum ship) * (1975–2008; decommissioned) * (1977–1992; scrapped) * (1985–2013; decommissioned) * (1989–present) * (1989–2014; decommissioned) * (1990–present) * (1992–present) * (2007–present) * (2020–present) * (2021–present) * (2022–present) * (2024–present)

Notes

Citations

References

* 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

The World Nuclear Association

Naval Nuclear Power Training Command
{{Authority control Marine propulsion *

Marine propulsion Marine propulsion is the mechanism or system used to generate thrust to move a watercraft through water. While paddles and sails are still used on some smaller boats, most modern ships are propelled by mechanical systems consisting of an electri ...

Power plants

Basic operation of naval ship or submarine

Differences from land power plants

Decommissioning

Future designs

Civil liability

Military nuclear ships

Submarines

Aircraft carriers

French Navy

United States Navy

Destroyers and cruisers

Russian Navy

United States Navy

Other military ships

Communication and command ships

Nuclear-powered UUV

Civilian nuclear ships

Merchant ships

Merchant cargo ships

Icebreakers

See also

Notes

Citations

References

External links