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Passive Autocatalytic Recombiner
Passive autocatalytic recombiner (PAR) is a device that removes hydrogen from the containment of a nuclear power plant during an accident. Its purpose is to prevent hydrogen explosions. Recombiners come into action spontaneously as soon as the hydrogen concentration increases. They are passive devices because their operation does not require external energy. Hydrogen may be generated in a nuclear accident if the reactor fuel overheats and zirconium cladding of the fuel rods reacts chemically with steam. If the hydrogen is released from the reactor to the containment, it may get mixed with air and form a flammable or even explosive mixture. A hydrogen explosion could break the containment and cause radioactive materials to be released to the environment. Recombiners aim at removing hydrogen and thereby preventing explosions. Inside a recombiner there are plates or pellets that are coated with platinum or palladium catalyst. On the surface of the catalyst, hydrogen and oxygen molecu ...
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Passive Autocatalytic Recombiner (PAR)
Passive may refer to: * Passive voice, a grammatical voice common in many languages, see also Pseudopassive (other), Pseudopassive * Passive language, a language from which an interpreter works * Passivity (behavior), the condition of submitting to the influence of one's superior * Passive-aggressive behavior, resistance to following through with expectations in interpersonal or occupational situations * Passive income, income resulting from cash flow received on a regular basis * Passive immunity, the transfer of active humoral immunity * Passive experience, observation lacking recipricol interaction; and wrought with delusion of control. Science and technology * Passivation (chemistry), process of making a material "passive" in relation to another material prior to using the materials together * Passivity (engineering) a property of engineering systems, particularly in analog electronics and control systems * Passive solar building design, which uses (or avoids) sunligh ...
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Catalysis
Catalysis () is the process of increasing the rate of a chemical reaction by adding a substance known as a catalyst (). Catalysts are not consumed in the reaction and remain unchanged after it. If the reaction is rapid and the catalyst recycles quickly, very small amounts of catalyst often suffice; mixing, surface area, and temperature are important factors in reaction rate. Catalysts generally react with one or more reactants to form intermediates that subsequently give the final reaction product, in the process of regenerating the catalyst. Catalysis may be classified as either homogeneous, whose components are dispersed in the same phase (usually gaseous or liquid) as the reactant, or heterogeneous, whose components are not in the same phase. Enzymes and other biocatalysts are often considered as a third category. Catalysis is ubiquitous in chemical industry of all kinds. Estimates are that 90% of all commercially produced chemical products involve catalysts at some s ...
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Nuclear Power Plant Components
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 operator *Nuclear congruence *Nuclear C*-algebra Biology Relating to the nucleus of the cell: * Nuclear DNA Society * Nuclear family, a family consisting of a pair of adults and their children Music * "Nuclear" (band), group music. * "Nuclear" (Ryan Adams song), 2002 *"Nuclear", a song by Mike Oldfield from his ''Man on the Rocks'' album * ''Nu.Clear'' (EP) by South Korean girl group CLC See also *Nucleus (other) *Nucleolus * Nucleation * Nucleic acid *Nucular ''Nucular'' is a common, proscribed pronunciation of the word "nuclear". It is a rough phonetic spelling of . The ''Oxford English Dictionary''s entry dates the word's first published appearance to 1943. Dictionary notes This is one of two con ...
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Hydrogen Safety
Hydrogen safety covers the safe production, handling and use of hydrogen, particularly hydrogen gas fuel and liquid hydrogen. Hydrogen possesses the NFPA 704's highest rating of 4 on the flammability scale because it is flammable when mixed even in small amounts with ordinary air; ignition can occur at a volumetric ratio of hydrogen to air as low as 4% due to the oxygen in the air and the simplicity and chemical properties of the reaction. However, hydrogen has no rating for innate hazard for reactivity or toxicity. The storage and use of hydrogen poses unique challenges due to its ease of leaking as a gaseous fuel, low-energy ignition, wide range of combustible fuel-air mixtures, buoyancy, and its ability to embrittle metals that must be accounted for to ensure safe operation. Liquid hydrogen poses additional challenges due to its increased density and the extremely low temperatures needed to keep it in liquid form. Moreover, its demand and use in industry—as rocket fuel, ...
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SNC-Lavalin
SNC-Lavalin Group Inc. is a Canadian company based in Montreal that provides engineering, procurement, and construction (EPC) services to various industries, including mining and metallurgy, oil and gas, environment and water, infrastructure, and clean energy. SNC-Lavalin is the largest construction company, by revenue, in Canada, as of 2018. The firm has over 50,000 employees worldwide, with offices in over 50 countries and operations in over 160 countries. Key sectors SNC Lavalin has over 50,000 employees worldwide, with offices in over 50 countries and operations in over 160 countries. According to its 2017 annual report, its four key service sectors are infrastructure, mining and metallurgy, oil and gas, and power; each sector offers services that includes design, studies, consultancy, financing, asset management, engineering, construction, procurement and operations and maintenance. Its infrastructure sector provides services from financing, building and maintenance. Its o ...
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EPR (nuclear Reactor)
The EPR is a third generation pressurised water reactor design. It has been designed and developed mainly by Framatome (part of Areva between 2001 and 2017) and Électricité de France (EDF) in France, and Siemens in Germany. In Europe this reactor design was called European Pressurised Reactor, and the internationalised name was Evolutionary Power Reactor, but it is now simply named EPR. The first operational EPR unit was China's Taishan 1, which started commercial operation in December 2018. Taishan 2 started commercial operation in September 2019. European units have been so far plagued with prolonged construction delays and substantial cost overruns. The first EPR unit to start construction, at Olkiluoto in Finland, achieved criticality in December 2021. It is expected to begin commercial operation after February 2023, a delay of thirteen years. The second EPR unit to start construction, at Flamanville in France, is also facing a decade-long delay (to 2024). T ...
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Olkiluoto 3
The Olkiluoto Nuclear Power Plant ( fi, Olkiluodon ydinvoimalaitos, sv, Olkiluoto kärnkraftverk) is one of Finland's two nuclear power plants, the other being the two-unit VVER Loviisa Nuclear Power Plant. The plant is owned and operated by Teollisuuden Voima Oyj (TVO), a subsidiary of Pohjolan Voima, and is located on Olkiluoto Island, on the shore of the Gulf of Bothnia, in the municipality of Eurajoki in western Finland, about 20 kilometres from the town of Rauma and about 50 kilometres from the city of Pori. The Olkiluoto plant consists of two boiling water reactors (BWRs), each producing 890  MW of electricity, together comprising 22% of the country's electricity generation for 2020. A third reactor, Unit 3, reached first criticality in late 2021, and at a nameplate capacity of 1,600 MW net electric output, will by itself satisfy 14% of the country's electricity demand. Unit 3 is an EPR reactor and has been under construction since 2005. The start of commercial o ...
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Framatome
Framatome () is a French nuclear reactor business. It is owned by Électricité de France (EDF) (75.5%), Mitsubishi Heavy Industries (19.5%), and Assystem (5%). The company first formed in 1958 to license Westinghouse's pressurized water reactor (PWR) designs for use in France. Similar agreements had been put in place with other European countries, and this led to a 1962 contract for a complete plant at Chooz. Westinghouse sold its stake to engineering firm Creusot-Loire in 1976, and the company became solely French owned. In 2001, Siemens sold its reactor business to Framatome. As part of a larger series of mergers with Cogema and Technicatome, Framatome became the Areva NP division of the new Areva. It changed its name back to Framatome in 2018 after a major investment by utility operator EDF. While originally a licensing and construction business, today Framatome supplies the entire reactor life-cycle, including design of the European Pressurized Reactor (EPR), construction, ...
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Palladium
Palladium is a chemical element with the symbol Pd and atomic number 46. It is a rare and lustrous silvery-white metal discovered in 1803 by the English chemist William Hyde Wollaston. He named it after the asteroid Pallas, which was itself named after the epithet of the Greek goddess Athena, acquired by her when she slew Pallas. Palladium, platinum, rhodium, ruthenium, iridium and osmium form a group of elements referred to as the platinum group metals (PGMs). They have similar chemical properties, but palladium has the lowest melting point and is the least dense of them. More than half the supply of palladium and its congener platinum is used in catalytic converters, which convert as much as 90% of the harmful gases in automobile exhaust (hydrocarbons, carbon monoxide, and nitrogen dioxide) into nontoxic substances (nitrogen, carbon dioxide and water vapor). Palladium is also used in electronics, dentistry, medicine, hydrogen purification, chemical applications, groundwate ...
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Hydrogen
Hydrogen is the chemical element with the symbol H and atomic number 1. Hydrogen is the lightest element. At standard conditions hydrogen is a gas of diatomic molecules having the formula . It is colorless, odorless, tasteless, non-toxic, and highly combustible. Hydrogen is the most abundant chemical substance in the universe, constituting roughly 75% of all normal matter.However, most of the universe's mass is not in the form of baryons or chemical elements. See dark matter and dark energy. Stars such as the Sun are mainly composed of hydrogen in the plasma state. Most of the hydrogen on Earth exists in molecular forms such as water and organic compounds. For the most common isotope of hydrogen (symbol 1H) each atom has one proton, one electron, and no neutrons. In the early universe, the formation of protons, the nuclei of hydrogen, occurred during the first second after the Big Bang. The emergence of neutral hydrogen atoms throughout the universe occurred about 370,000 ...
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Platinum
Platinum is a chemical element with the symbol Pt and atomic number 78. It is a dense, malleable, ductile, highly unreactive, precious, silverish-white transition metal. Its name originates from Spanish , a diminutive of "silver". Platinum is a member of the platinum group of elements and group 10 of the periodic table of elements. It has six naturally occurring isotopes. It is one of the rarer elements in Earth's crust, with an average abundance of approximately 5  μg/kg. It occurs in some nickel and copper ores along with some native deposits, mostly in South Africa, which accounts for ~80% of the world production. Because of its scarcity in Earth's crust, only a few hundred tonnes are produced annually, and given its important uses, it is highly valuable and is a major precious metal commodity. Platinum is one of the least reactive metals. It has remarkable resistance to corrosion, even at high temperatures, and is therefore considered a noble metal. Consequent ...
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Zirconium
Zirconium is a chemical element with the symbol Zr and atomic number 40. The name ''zirconium'' is taken from the name of the mineral zircon, the most important source of zirconium. The word is related to Persian '' zargun'' (zircon; ''zar-gun'', "gold-like" or "as gold"). It is a lustrous, grey-white, strong transition metal that closely resembles hafnium and, to a lesser extent, titanium. Zirconium is mainly used as a refractory and opacifier, although small amounts are used as an alloying agent for its strong resistance to corrosion. Zirconium forms a variety of inorganic and organometallic compounds such as zirconium dioxide and zirconocene dichloride, respectively. Five isotopes occur naturally, four of which are stable. Zirconium compounds have no known biological role. Characteristics Zirconium is a lustrous, greyish-white, soft, ductile, malleable metal that is solid at room temperature, though it is hard and brittle at lesser purities. In powder form, zirconium is highl ...
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