Pressurized water reactors (PWRs) constitute the large majority of the world's nuclear power plants and are one of three types of light-water reactor (LWR), the other types being boiling water reactors (BWRs) and supercritical water reactors (SCWRs). 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 water then flows to a steam generator where it transfers its thermal energy to a secondary system where steam is generated and flows to turbines which, in turn, spin an electric generator. In contrast to a boiling water reactor, pressure in the primary coolant loop prevents the water from boiling within the reactor. All LWRs use ordinary water as both coolant and neutron moderator. Most use anywhere from 2 to 4 vertically mounted steam generators; VVER reactors use horizontal steam generators.
The nuclear fuel cycle, also called nuclear fuel chain, is the progression of nuclear fuel through a series of differing stages. It consists of steps in the front end, which are the preparation of the fuel, steps in the service period in which the fuel is used during reactor operation, and steps in the back end, which are necessary to safely manage, contain, and either reprocess or dispose of spent nuclear fuel. If spent fuel is not reprocessed, the fuel cycle is referred to as an open fuel cycle ; if the spent fuel is reprocessed, it is referred to as a closed fuel cycle.
Otto Hahn was one of only four nuclear-powered cargo vessels built to date. Planning of a German-built trade and research vessel to test the feasibility of nuclear power in civil service began in 1960 under the supervision of the German physicist Erich Bagge. Launched in 1964, her nuclear reactor was deactivated fifteen years later in 1979 and replaced by a conventional Diesel engine room. The ship was scrapped in 2009.
Sevmorput is a Russian nuclear-powered icebreaking LASH carrier and container ship. Named after the Northern Sea Route, the 1988-built ship is one of only four nuclear-powered merchant ships ever built. After having been laid up in Murmansk for years awaiting disposal, the vessel was extensively refitted and returned to service in 2016.
A nuclear-powered icebreaker is a nuclear-powered ship purpose-built for use in waters covered with ice. The only country constructing nuclear-powered icebreakers is Russia. Nuclear-powered icebreakers have been constructed by the Soviet Union and later Russia primarily to aid shipping along the Northern Sea Route in the frozen Arctic waterways north of Siberia. Nuclear-powered icebreakers are much more powerful than their diesel-powered counterparts, and although nuclear propulsion is expensive to install and maintain, very heavy fuel demands and limitations on range, compounded with the difficulty of refueling in arctic region, can make diesel vessels less practical and economical overall for these ice-breaking duties.
Lenin is a Soviet nuclear-powered icebreaker. Launched in 1957, it was both the world's first nuclear-powered surface ship and the first nuclear-powered civilian vessel. Lenin entered operation in 1959 and worked clearing sea routes for cargo ships along Russia's northern coast. From 1960 to 1965 the ship covered over 85,000 miles during the Arctic navigation season, of which almost 65,000 were through ice. Nuclear power proved to be an ideal technology for a vessel working in such a remote area as it removed the need for regular replenishment of fuel. On April 10, 1974 the vessel was awarded the Order of Lenin. It was officially decommissioned in 1989. It was subsequently converted to a museum ship and is now permanently based at Murmansk.
Nuclear marine propulsion is propulsion of a ship or submarine with heat provided by a nuclear power plant. 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. Naval nuclear propulsion is used specifically within naval warships such as 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.
TRIGA is a class of nuclear research reactor designed and manufactured by General Atomics. The design team for TRIGA, which included Edward Teller, was led by the physicist Freeman Dyson.
Nuclear fuel is material used in nuclear power stations to produce heat to power turbines. Heat is created when nuclear fuel undergoes nuclear fission.
Experimental Breeder Reactor-II (EBR-II) is a sodium-cooled fast reactor designed, built and operated by Argonne National Laboratory at the National Reactor Testing Station in Idaho. It was shut down in 1994. Custody of the reactor was transferred to Idaho National Laboratory after its founding in 2005.
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. Ships of the Arktika class are owned by the federal government, but were operated by the Murmansk Shipping Company (MSCO) until 2008, when they were transferred to the fully government-owned operator Atomflot. Of the ten civilian nuclear-powered vessels built by Russia, six have been of this type. They are used for escorting merchant ships in the Arctic Ocean north of Siberia as well as for scientific and recreational expeditions to the Arctic.
The OK-650 reactor is the nuclear fission reactor used for the powering the Soviet Navy's Project 685 Плавник/Plavnik (Mike), Project 971 Щука-Б/Shchuka-B (Akula), and Project 945 Барракуда/Barrakuda, Кондор/Kondor, and Марс/Mars (Sierra) submarines, and in pairs to power the Project 941 Акула/Akula (Typhoon) and Project 949 Гранит/Granit and Антей/Antei (Oscar) third generation submarines.
The KLT-40 family are nuclear fission reactors originating from OK-150 and OK-900 ship reactors. KLT-40 were developed to power the Taymyr-class icebreakers and the LASH carrier Sevmorput. They are pressurized water reactors (PWR) fueled by either 30–40% or 90% enriched uranium-235 fuel to produce 135 to 171 MW of thermal power.
This page describes how uranium dioxide nuclear fuel behaves during both normal nuclear reactor operation and under reactor accident conditions, such as overheating. Work in this area is often very expensive to conduct, and so has often been performed on a collaborative basis between groups of countries, usually under the aegis of the Organisation for Economic Co-operation and Development's Committee on the Safety of Nuclear Installations (CSNI).
A gas-cooled reactor (GCR) is a nuclear reactor that uses graphite as a neutron moderator and carbon dioxide as coolant. Although there are many other types of reactor cooled by gas, the terms GCR and to a lesser extent gas cooled reactor are particularly used to refer to this type of reactor.
The UNGG is an obsolete nuclear power reactor design developed in France. It was graphite moderated, cooled by carbon dioxide, and fueled with natural uranium metal. The first generation of French nuclear power stations were UNGGs, as was Vandellos unit 1 in Spain. Of ten units built, all were shut down by end 1994, most for economic reasons due to staffing costs.
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.
The Nuclear Fuel Complex (NFC) was established in 1971 as a major industrial unit of India's Department of Atomic Energy, as a nuclear power plant also specializing in supply of nuclear fuel bundles and reactor core components. It is a unique facility where natural and enriched uranium fuel, zirconium alloy cladding and reactor core components are manufactured under one roof.
An organic nuclear reactor, or organic cooled reactor (OCR), is a type of nuclear reactor that uses some form of organic fluid, typically a hydrocarbon substance like polychlorinated biphenyl (PCB), for cooling and sometimes as a neutron moderator as well.
