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 radioactive decay.
A nuclear reactor is a device used to initiate and control a fission nuclear chain reaction or nuclear fusion reactions. Nuclear reactors are used at nuclear power plants for electricity generation and in nuclear marine propulsion. Heat from nuclear fission is passed to a working fluid, which in turn runs through steam turbines. These either drive a ship's propellers or turn electrical generators' shafts. Nuclear generated steam in principle can be used for industrial process heat or for district heating. Some reactors are used to produce isotopes for medical and industrial use, or for production of weapons-grade plutonium. As of 2022, the International Atomic Energy Agency reports there are 422 nuclear power reactors and 223 nuclear research reactors in operation around the world.
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. In a PWR, the primary coolant (water) is pumped under high pressure to the reactor core where it is heated by the energy released by the fission of atoms. The heated, high pressure water then flows to a steam generator, where it transfers its thermal energy to lower pressure water of a secondary system where steam is generated. The steam then drives turbines, which spin an electric generator. In contrast to a boiling water reactor (BWR), pressure in the primary coolant loop prevents the water from boiling within the reactor. All light-water reactors use ordinary water as both coolant and neutron moderator. Most use anywhere from two to four vertically mounted steam generators; VVER reactors use horizontal steam generators.
A steamship, often referred to as a steamer, is a type of steam-powered vessel, typically ocean-faring and seaworthy, that is propelled by one or more steam engines that typically move (turn) propellers or paddlewheels. The first steamships came into practical usage during the early 1800s; however, there were exceptions that came before. Steamships usually use the prefix designations of "PS" for paddle steamer or "SS" for screw steamer. As paddle steamers became less common, "SS" is assumed by many to stand for "steamship". Ships powered by internal combustion engines use a prefix such as "MV" for motor vessel, so it is not correct to use "SS" for most modern vessels.
NS Savannah was the first nuclear-powered merchant ship. She was built in the late 1950s at a cost of $46.9 million and launched on July 21, 1959. She was funded by United States government agencies. Savannah was a demonstration project for the potential use of nuclear energy. The ship was named after SS Savannah, the first steamship to cross the Atlantic ocean. She was in service between 1962 and 1972 as one of only four nuclear-powered cargo ships ever built.
The Alfa class, Soviet designation Project 705 Lira, was a class of nuclear-powered attack submarines in service with the Soviet Navy from 1971 into the early 1990s, with one serving later with the Russian Navy until 1996. They were among the fastest military submarines ever built, with only the prototype submarine K-222 exceeding them in submerged speed.
Sevmorput is a Russian nuclear-powered cargo ship. The 1988-built vessel is one of only four nuclear-powered merchant ships ever built and, after returning to service in 2016 following an extensive refit, the only such vessel to remain in service as of 2023.
USS Virginia (SSN-774) is a nuclear powered cruise missile attack submarine and the lead ship of her class, currently serving in the United States Navy (USN). She is the tenth vessel of the Navy to be named for the Commonwealth of Virginia, as well as the second US Navy attack submarine to be named after a state, a pattern that is common throughout her class.
Nuclear marine propulsion is propulsion of a ship or submarine with heat provided by a nuclear reactor. The power plant heats water to produce steam for a turbine used to turn the ship's propeller through a gearbox or through an electric generator and motor. Nuclear propulsion is used primarily within naval warships such as nuclear submarines and supercarriers. A small number of experimental civil nuclear ships have been built.
The light-water reactor (LWR) is a type of thermal-neutron reactor that uses normal water, as opposed to heavy water, as both its coolant and neutron moderator; furthermore a solid form of fissile elements is used as fuel. Thermal-neutron reactors are the most common type of nuclear reactor, and light-water reactors are the most common type of thermal-neutron reactor.
The Arktika class is a Russian class of nuclear-powered icebreakers. Formerly known as Project 10520 nuclear-powered icebreaker, they were the world's largest and most powerful icebreakers until the 2016 launch of the first Project 22220 icebreaker, also named Arktika.
The X-10 Graphite Reactor is a decommissioned nuclear reactor at Oak Ridge National Laboratory in Oak Ridge, Tennessee. Formerly known as the Clinton Pile and X-10 Pile, it was the world's second artificial nuclear reactor, and the first designed and built for continuous operation. It was built during World War II as part of the Manhattan Project.
The German Maritime Museum is a museum in Bremerhaven, Germany. It is part of the Gottfried Wilhelm Leibniz Scientific Community. The main museum building was opened on 5 September 1975 by then-president of Germany Walter Scheel, though scientific work already had started in 1971. In 2000, celebrating the 25th anniversary of the museum, the Hansekogge, a ship constructed around 1380 that was found in the Weser river in 1962, was presented to the public after having undergone a lengthy process of conservation in a large preservative-filled basin.
A merchant submarine is a type of submarine intended for trade, and being without armaments, it is not considered a warship like most other types of submarines. The intended use would be blockade running, or to dive under Arctic ice.
MH-1A was the first floating nuclear power station. Named Sturgis after General Samuel D. Sturgis, Jr., this pressurized water reactor built in a converted Liberty ship was part of a series of reactors in the US Army Nuclear Power Program, which aimed to develop small nuclear reactors to generate electrical and space-heating energy primarily at remote, relatively inaccessible sites. Its designation stood for mobile, high power. After its first criticality in 1967, MH-1A was towed to the Panama Canal Zone that it supplied with 10 MW of electricity. Its dismantling began in 2014 and was completed in March 2019.
SS Charles H. Cugle was a Type Z-EC2-S-C5 Liberty ship built by J.A. Jones Construction of Panama City, Florida, launched on 13 August 1945. It was ordered by the War Shipping Administration under Maritime Commission Contract number 3145.
Taymyr is a shallow-draft nuclear-powered icebreaker, and the first of two similar vessels. She was built in 1989 for the Soviet Union in Finland, at the Helsinki Shipyard by Wärtsilä Marine, by order of the Murmansk Shipping Company. Her sister ship is Vaygach.
Vaygach is a shallow-draught nuclear-powered icebreaker. She was built in 1989 for the Soviet Union by Wärtsilä Marine Helsinki Shipyard in Finland by order of the Murmansk Shipping Company and its KL-40 reactor was installed at the Baltic Shipyard in St. Petersburg. Her sister ship is Taymyr.
USS Delaware (SSN-791) is a Virginia-class attack submarine built for the United States Navy. The contract to build her was awarded to Huntington Ingalls Industries in partnership with the Electric Boat division of General Dynamics in Newport News, Virginia on 22 December 2008. This boat is the eighth and final of the Block III submarines that feature a revised bow, including some technology from Ohio-class SSGNs. Construction on Delaware began in September 2013. She was christened on 20 October 2018. She was commissioned administratively after the standard commissioning ceremony was cancelled due to public health concerns over the COVID-19 coronavirus pandemic. Delaware was the first ever US ship commissioned while underwater. The official commissioning ceremony occurred 2 April 2022 at the Port of Wilmington, Delaware.
RV Mirai is a Japanese oceanographic research vessel. She was originally built as the nuclear-powered general cargo ship Mutsu, but never carried commercial cargo.
