Pressurized water reactor in the context of "Containment building"

An internal combustion engine (ICE or IC engine) is a heat engine in which the combustion of a fuel occurs with an oxidizer (usually air) in a combustion chamber that is an integral part of the working fluid flow circuit. In an internal combustion engine, the expansion of the high-temperature and high-pressure gases produced by combustion applies direct force to components of the engine. The force is typically applied to pistons (piston engine), turbine blades (gas turbine), a rotor (Wankel engine), or a nozzle (jet engine). This force moves the component over a distance. This process transforms chemical energy into kinetic energy which is used to propel, move or power whatever the engine is attached to.

The first commercially successful internal combustion engines were invented in the mid-19th century. The first modern internal combustion engine, the Otto engine, was designed in 1876 by the German engineer Nicolaus Otto. The term internal combustion engine usually refers to an engine in which combustion is intermittent, such as the more familiar two-stroke and four-stroke piston engines, along with variants, such as the six-stroke piston engine and the Wankel rotary engine. A second class of internal combustion engines use continuous combustion: gas turbines, jet engines and most rocket engines, each of which are internal combustion engines on the same principle as previously described. In contrast, in external combustion engines, such as steam or Stirling engines, energy is delivered to a working fluid not consisting of, mixed with, or contaminated by combustion products. Working fluids for external combustion engines include air, hot water, pressurized water or even boiler-heated liquid sodium.

A nuclear meltdown (core meltdown, core melt accident, meltdown or partial core melt) is a severe nuclear reactor accident that results in core damage from overheating. The term nuclear meltdown is not officially defined by the International Atomic Energy Agency, however it has been defined to mean the accidental melting of the core or fuel of a nuclear reactor, and is in common usage a reference to the core's either complete or partial collapse.

A core meltdown accident occurs when the heat generated by a nuclear reactor exceeds the heat removed by the cooling systems to the point where at least one nuclear fuel element exceeds its melting point. This differs from a fuel element failure, which is not caused by high temperatures. A meltdown may be caused by a loss of coolant, loss of coolant pressure, or low coolant flow rate, or be the result of a criticality excursion in which the reactor's power level exceeds its design limits.

A steam explosion is an explosion caused by violent boiling or flashing of water or ice into steam, occurring when water or ice is either superheated, rapidly heated by fine hot debris produced within it, or heated by the interaction of molten metals (as in a fuel–coolant interaction, or FCI, of molten nuclear-reactor fuel rods with water in a nuclear reactor core following a core-meltdown). Steam explosions are instances of explosive boiling. Pressure vessels, such as pressurized water (nuclear) reactors, that operate above atmospheric pressure can also provide the conditions for a steam explosion. The water changes from a solid or liquid to a gas with extreme speed, increasing dramatically in volume. A steam explosion sprays steam and boiling-hot water and the hot medium that heated it in all directions (if not otherwise confined, e.g. by the walls of a container), creating a danger of scalding and burning.

Steam explosions are not normally chemical explosions, although a number of substances react chemically with steam (for example, zirconium and superheated graphite (inpure carbon, C) react with steam and air respectively to give off hydrogen (H₂), which may explode violently in air (O₂) to form water or H₂O) so that chemical explosions and fires may follow. Some steam explosions appear to be special kinds of boiling liquid expanding vapor explosion (BLEVE), and rely on the release of stored superheat. But many large-scale events, including foundry accidents, show evidence of an energy-release front propagating through the material (see description of FCI below), where the forces create fragments and mix the hot phase into the cold volatile one; and the rapid heat transfer at the front sustains the propagation.

Électricité de France SA (French pronunciation: [elɛktʁisite də fʁɑ̃s]; lit. 'Electricity of France'), commonly known as EDF, is a French multinational electric utility company owned by the government of France. Headquartered in Paris, with €139.7 billion in sales in 2023, EDF operates a diverse portfolio of at least 120 gigawatts of generation capacity in Europe, South America, North America, Asia, the Middle East, and Africa. In 2009, EDF was the world's largest producer of electricity. Its 56 active nuclear reactors in France are spread out over 18 sites (18 nuclear power plants). They comprise 32 reactors of 900 MW_e, 20 reactors of 1,300 MW_e, and 4 reactors of 1,450 MW_e, all PWRs.

EDF was created on 8 April 1946 by the 1945 parliament, from the merging of various divided actors. EDF led France's post-war energy growth, with a unique focus on civil nuclear energy, through reconstruction and further industrialization within the Trente Glorieuses, being a flagship of France's new industrial landscape. In 2004, following integration into the European Common Market, EDF was privatized, although the government of France retained 84% equity. In 2017 EDF took over the majority of the reactor business Areva, in a French government-sponsored restructuring. That same year, following a wish to divest from nuclear energy, the possible closure of 17 of EDF's French nuclear power reactors by 2025 was announced. By 2022, this decision had been reversed, with the administration of president Emmanuel Macron announcing plans for a "nuclear renaissance", beginning with the projected construction of 6 EPR model 2 reactors with an option for 8 further reactors. Meanwhile, construction is ongoing on EPR model 1 reactors in France and Britain.

The Nimitz class is a class of ten nuclear-powered aircraft carriers in service with the United States Navy. The lead ship of the class is named after World War II United States Pacific Fleet commander Fleet Admiral Chester W. Nimitz, who was the last living U.S. Navy officer to hold the rank. With an overall length of 1,092 ft (333 m) and a full-load displacement of over 100,000 long tons (100,000 t), the Nimitz-class ships were the largest warships built and in service until USS Gerald R. Ford entered the fleet in 2017.

Instead of the gas turbines or diesel–electric systems used for propulsion on many modern warships, the carriers use two A4W pressurized water reactors. The reactors produce steam to drive steam turbines which drive four propeller shafts and can produce a maximum speed of over 30 knots (56 km/h; 35 mph) and a maximum power of around 260,000 shaft horsepower (190 MW). As a result of nuclear power, the ships are capable of operating for over 20 years without refueling and are predicted to have a service life of over 50 years. They are categorized as nuclear-powered aircraft carriers and are numbered with consecutive hull numbers from CVN-68 to CVN-77.

A containment building is a reinforced steel, concrete or lead structure enclosing a nuclear reactor. It is designed, in any emergency, to contain the escape of radioactive steam or gas to a maximum pressure in the range of 275 to 550 kPa (40 to 80 psi). The containment is the fourth and final barrier to radioactive release (part of a nuclear reactor's defence in depth strategy), the first being the fuel ceramic itself, the second being the metal fuel cladding tubes, the third being the reactor vessel and coolant system.

Each nuclear plant in the United States is designed to withstand certain conditions which are spelled out as "Design Basis Accidents" in the Final Safety Analysis Report (FSAR). The FSAR is available for public viewing, usually at a public library near the nuclear plant.

Obrigheim Nuclear Power Plant (KWO) is a nuclear power plant currently in the decommissioning phase. The plant is located in Obrigheim, Neckar-Odenwald-Kreis, on the banks of the Neckar and owned by EnBW. It operated a pressurized water reactor unit from 1969 to 2005. The defuelling process was completed in 2007, with spent fuel rods awaiting transport to an interim storage facility. In March 2017, EnBW tested the shipment of numerous castors by a barge on the Neckar to Neckarwestheim Nuclear Power Plant.

The Zaporizhzhia Nuclear Power Station (Ukrainian: Запорізька атомна електростанція, romanized: Zaporiz'ka atomna elektrostantsiia; Russian: Запорожская атомная электростанция, romanized: Zaporozhskaya atmonaya elektrostantsiya) in southeastern Ukraine is the largest nuclear power plant in Europe and among the 10 largest in the world. It has been under Russian control since 2022. It was built by the Soviet Union near the city of Enerhodar, on the southern shore of the Kakhovka Reservoir on the Dnieper river. From 1996 to 2022, it was operated by Energoatom, which operates Ukraine's other three nuclear power stations.

The plant has six VVER-1000 pressurized light water nuclear reactors (PWR), each fueled with U (LEU) and generating 950 MW_e, for a total power output of 5,700 MW_e. The first five were successively brought online between 1985 and 1989, and the sixth was added in 1995. In 2020, the plant generated nearly half of the country's electricity derived from nuclear power, and more than a fifth of total electricity generated in Ukraine. The Zaporizhzhia thermal power station is nearby.