A nuclear reactor is a device used to initiate and control a fission nuclear chain reaction. Nuclear reactors are used at nuclear power plants for electricity generation and in nuclear marine propulsion. When a fissile nucleus like uranium-235 or plutonium-239 absorbs a neutron, it splits into lighter nuclei, releasing energy, gamma radiation, and free neutrons, which can induce further fission in a self-sustaining chain reaction. The process is carefully controlled using control rods and neutron moderators to regulate the number of neutrons that continue the reaction, ensuring the reactor operates safely, although inherent control by means of delayed neutrons also plays an important role in reactor output control. The efficiency of nuclear fuel is much higher than fossil fuels; the 5% enriched uranium used in the newest reactors has an energy density 120,000 times higher than coal.
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 nuclear fission of uranium and plutonium in nuclear power plants. Nuclear decay processes are used in niche applications such as radioisotope thermoelectric generators in some space probes such as Voyager 2. Reactors producing controlled fusion power have been operated since 1958, but have yet to generate net power and are not expected to be commercially available in the near future.
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 nuclear power plant (NPP), also known as a nuclear power station (NPS), nuclear generating station (NGS) or atomic power station (APS) is a thermal power station in which the heat source is a nuclear reactor. As is typical of thermal power stations, heat is used to generate steam that drives a steam turbine connected to a generator that produces electricity. As of September 2023, the International Atomic Energy Agency reported that there were 410 nuclear power reactors in operation in 32 countries around the world, and 57 nuclear power reactors under construction.
The Vallecitos Nuclear Center is a nuclear research facility, and the site of a former GE Hitachi Nuclear Energy electricity-generating nuclear power plant in unincorporated Alameda County, California, United States. The facility is approximately 30 miles (48 km) east of San Francisco, under jurisdiction of the US Nuclear Regulatory Commission's Region IV.
The Enrico Fermi Nuclear Generating Station is a nuclear power plant on the shore of Lake Erie near Monroe, in Frenchtown Charter Township, Michigan on approximately 1,000 acres (400 ha). All units of the plant are operated by the DTE Energy Electric Company and owned by parent company DTE Energy. It is approximately halfway between Detroit, Michigan, and Toledo, Ohio. It is also visible from parts of Amherstburg and Colchester, Ontario as well as on the shore of Lake Erie in Ottawa County, Ohio. Two units have been constructed on this site. The first unit's construction started on August 4, 1956 and reached initial criticality on August 23, 1963, and the second unit received its construction permit on September 26, 1972. It reached criticality on June 21, 1985 and was declared commercial on November 18, 1988. The plant is connected to two single-circuit 345 kV Transmission Lines and three 120 kV lines. They are operated and maintained by ITC Transmission.
The Shippingport Atomic Power Station was the world's first full-scale atomic electric power plant devoted exclusively to peacetime uses. It was located near the present-day Beaver Valley Nuclear Generating Station on the Ohio River in Beaver County, Pennsylvania, United States, about 25 miles (40 km) from Pittsburgh.
The Lucens reactor was a 6 MW experimental nuclear power reactor built next to Lucens, Vaud, Switzerland. After its connection to the electrical grid on 29 January 1968, the reactor only operated for a year before it suffered an accident on 21 January 1969. The cause was a corrosion-induced loss of heat dispersal leading to the destruction of a pressure tube which caused an adjacent pressure tube to fail, and partial meltdown of the core, resulting in radioactive contamination of the cavern.
A nuclear power phase-out is the discontinuation of usage of nuclear power for energy production. Often initiated because of concerns about nuclear power, phase-outs usually include shutting down nuclear power plants and looking towards fossil fuels and renewable energy. Three nuclear accidents have influenced the discontinuation of nuclear power: the 1979 Three Mile Island partial nuclear meltdown in the United States, the 1986 Chernobyl disaster in the USSR, and the 2011 Fukushima nuclear disaster in Japan.
Generation IVreactors are nuclear reactor design technologies that are envisioned as successors of generation III reactors. The Generation IV International Forum (GIF) – an international organization that coordinates the development of generation IV reactors – specifically selected six reactor technologies as candidates for generation IV reactors. The designs target improved safety, sustainability, efficiency, and cost. The World Nuclear Association in 2015 suggested that some might enter commercial operation before 2030.
The THTR-300 was a thorium cycle high-temperature nuclear reactor rated at 300 MW electric (THTR-300) in Hamm-Uentrop, Germany. It started operating in 1983, synchronized with the grid in 1985, operated at full power in February 1987 and was shut down September 1, 1989. The THTR-300 served as a prototype high-temperature reactor (HTR) to use the TRISO pebble fuel produced by the AVR, an experimental pebble bed operated by VEW. The THTR-300 cost €2.05 billion and was predicted to cost an additional €425 million through December 2009 in decommissioning and other associated costs. The German state of North Rhine Westphalia, Federal Republic of Germany, and Hochtemperatur-Kernkraftwerk GmbH (HKG) financed the THTR-300’s construction.
Madras Atomic Power Station (MAPS) located at Kalpakkam about 80 kilometres (50 mi) south of Chennai, India, is a comprehensive nuclear power production, fuel reprocessing, and waste treatment facility that includes plutonium fuel fabrication for fast breeder reactors (FBRs). It is also India's first fully indigenously constructed nuclear power station, with two units each generating 220 MW of electricity. The first and second units of the station went critical in 1983 and 1985, respectively. The station has reactors housed in a reactor building with double shell containment improving protection also in the case of a loss-of-coolant accident. An Interim Storage Facility (ISF) is also located in Kalpakkam.
Since the mid 1980s, the largest source of electricity in France has been nuclear power, with a generation of 379.5 TWh in 2019 and a total electricity production of 537.7 TWh. In 2018, the nuclear share was 71.67%, the highest percentage in the world.
Floating nuclear power stations are vessels designed by Rosatom, the Russian state-owned nuclear energy corporation. They are self-contained, low-capacity, floating nuclear power plants. Rosatom plans to mass-produce the stations at shipbuilding facilities and then tow them to ports near locations that require electricity.
Brokdorf Nuclear Power Plant is a Power Plant close to the municipality of Brokdorf in Steinburg, Schleswig-Holstein, Germany that shut down on New Year's Eve 2021.
The Gundremmingen Nuclear Power Plant was a nuclear power station in Germany. It was located in Gundremmingen, district of Günzburg, Bavaria. It was operated by Kernkraftwerk Gundremmingen GmbH, a joint operation of RWE Power AG (75%) and PreussenElektra (25%). Unit B was shut down at the end of 2017. Unit C, the last boiling water reactor in Germany, was shut down on New Year's Eve 2021, as part of the German nuclear phase out. However, Gundremmingen unit C as well as the other two German nuclear reactors shut down that day remained capable of restarting operations in March 2022. In November 1975, Unit A was the site of the first fatal accident in a nuclear power plant in Germany, though the accident was unrelated to radiation. After a later major incident in 1977, Unit A was never returned to service.
The Ågesta Nuclear Plant was the first Swedish commercial nuclear power plant built by ASEA. Also known as R3 nuclear reactor, it was the third nuclear reactor built in Sweden. Construction started in 1957 and ended in 1962, operations began in 1964 and continued until 1974.
China is one of the world's largest producers of nuclear power. The country ranks third in the world both in total nuclear power capacity installed and electricity generated, accounting for around one tenth of global nuclear power generated. As of February 2023, China has 55 plants with 57GW in operation, 22 under construction with 24 GW and more than 70 planned with 88GW. About 5% of electricity in the country is due to nuclear energy. These plants generated 417 TWh of electricity in 2022 This is versus the September 2022 numbers of 53 nuclear reactors, with a total capacity of 55.6 gigawatt (GW). In 2019, nuclear power had contributed 4.9% of the total Chinese electricity production, with 348.1 TWh.
TerraPower is an American nuclear reactor design and development engineering company headquartered in Bellevue, Washington. TerraPower is developing a class of nuclear fast reactors termed traveling wave reactors (TWR).
Several nuclear reactors in Germany and abroad are referred to as Pre-Konvoi. The term means that these units were produced and constructed before the manufacturer, Kraftwerk Union AG (KWU), switched over to a standardized design for this type of pressurized water reactor.
