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Liquid Metal Cooled Reactor
A liquid metal cooled nuclear reactor (LMR) is a type of nuclear reactor where the primary coolant is a liquid metal. Liquid metal cooled reactors were first adapted for breeder reactor power generation. They have also been used to power nuclear submarines. Due to their high thermal conductivity, metal coolants remove heat effectively, enabling high power density. This makes them attractive in situations where size and weight are at a premium, like on ships and submarines. Most water-based reactor designs are highly pressurized to raise the boiling point (thereby improving cooling capabilities), which presents safety and maintenance issues that liquid metal designs lack. Additionally, the high temperature of the liquid metal can be used to drive power conversion cycles with high thermodynamic efficiency. This makes them attractive for improving power output, cost effectiveness, and fuel efficiency in nuclear power plants. Liquid metals, being electrically highly conductive, can ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nuclear Reactor
A nuclear reactor is a device used to initiate and control a Nuclear fission, fission nuclear chain reaction. They are used for Nuclear power, commercial electricity, nuclear marine propulsion, marine propulsion, Weapons-grade plutonium, weapons production and Research reactor, research. Fissile material, Fissile nuclei (primarily uranium-235 or plutonium-239) absorb single neutron, neutrons and split, releasing energy and multiple neutrons, which can induce further fission. Reactors stabilize this, regulating Neutron absorber, neutron absorbers and neutron moderator, moderators in the core. Fuel efficiency is exceptionally high; Enriched uranium#Low-enriched uranium (LEU), low-enriched uranium is 120,000 times more energy dense than coal. Heat from nuclear fission is passed to a working fluid Nuclear reactor#By coolant, coolant. In commercial reactors, this drives Turbine, turbines and electrical generator shafts. Some reactors are used for district heating, and isotopes, isoto ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ambient Pressure
The ambient pressure on an object is the pressure of the surrounding medium, such as a gas or liquid, in contact with the object. Atmosphere Within the atmosphere, the ambient pressure decreases as elevation increases. By measuring ambient atmospheric pressure, a pilot may determine altitude (see pitot-static system). Near sea level, a change in ambient pressure of 1 millibar is taken to represent a change in height of . Underwater The ambient pressure in water with a free surface is a combination of the hydrostatic pressure due to the weight of the water column and the atmospheric pressure on the free surface. This increases approximately linearly with depth. Since water is much denser than air, much greater changes in ambient pressure can be experienced under water. Each of depth adds another bar (unit) , bar to the ambient pressure. Ambient-pressure diving is underwater diving exposed to the water pressure at depth, rather than in a pressure-excluding atmospheric diving suit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neutron Activation
Neutron activation is the process in which neutron radiation induces radioactivity in materials, and occurs when atomic nuclei capture free neutrons, becoming heavier and entering excited states. The excited nucleus decays immediately by emitting gamma rays, or particles such as beta particles, alpha particles, fission products, and neutrons (in nuclear fission). Thus, the process of neutron capture, even after any intermediate decay, often results in the formation of an unstable activation product. Such radioactive nuclei can exhibit half-lives ranging from small fractions of a second to many years. Neutron activation is the only common way that a stable material can be induced into becoming intrinsically radioactive. All naturally occurring materials, including air, water, and soil, can be induced (activated) by neutron capture into some amount of radioactivity in varying degrees, as a result of the production of neutron-rich radioisotopes. Some atoms require more th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Monju Nuclear Power Plant
was a Japanese sodium-cooled fast reactor, located near the Tsuruga Nuclear Power Plant, Fukui Prefecture. Its name is a reference to Manjusri. Construction started in 1986 and the reactor achieved criticality for the first time in April 1994. The reactor has been inoperative for most of the time since it was originally built. It was last operated in 2010 and is now closed. Monju was a sodium cooled, MOX-fueled, loop-type reactor with three primary coolant loops, designed to produce 280 MWe from 714 MWt. It had a breeding ratio of approximately 1.2. The plant is located on a site that spans 1.08 km2 (267 acres), the buildings occupy 28,678 m2 (7 acres), and it has 104,680 m2 of floor space. An accident in December 1995, in which a sodium leak caused a major fire, forced a shutdown. A subsequent scandal involving a cover-up of the scope of the accident delayed its restart until May 6, 2010, with renewed criticality reached on May 8, 2010. In August 2010 anoth ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Experimental Breeder Reactor-1
Experimental Breeder Reactor I (EBR-I) is a decommissioned research reactor and U.S. National Historic Landmark located in the desert about southeast of Arco, Idaho. It was the world's first breeder reactor. At 1:50 p.m. on December 20, 1951, it became one of the world's first electricity-generating nuclear power plants when it produced sufficient electricity to illuminate four 200-watt light bulbs. EBR-I soon generated sufficient electricity to power its building and the town of Arco, and continued to be used for experimental research until it was decommissioned in 1964. The museum is open for visitors from late May until early September. History EBR-I's construction started in late 1949. The reactor was designed and built by a team led by Walter Zinn at the Idaho site of the Argonne National Laboratory, known as Argonne-West (since 2005 part of Idaho National Laboratory). In its early stages, the reactor plant was referred to as Chicago Pile 4 (CP-4) and Zinn's ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neutron Cross-section
In nuclear physics, the concept of a neutron cross section is used to express the likelihood of interaction between an incident neutron and a target nucleus. The neutron cross section σ can be defined as the area in cm2 for which the number of neutron-nuclei reactions taking place is equal to the product of the number of incident neutrons that would pass through the area and the number of target nuclei. In conjunction with the neutron flux, it enables the calculation of the reaction rate, for example to derive the thermal power of a nuclear power plant. The standard unit for measuring the cross section is the barn, which is equal to 10−28 m2 or 10−24 cm2. The larger the neutron cross section, the more likely a neutron will react with the nucleus. An isotope (or nuclide) can be classified according to its neutron cross section and how it reacts to an incident neutron. Nuclides that tend to absorb a neutron and either decay or keep the neutron in its nucleus are neutron a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Los Alamos Science
''Los Alamos Science'' was the Los Alamos National Laboratory's flagship publication in the years 1980 to 2005. Its main purpose was to present the laboratory's research and its significance to national security to the scientific community, and US government policymakers. Special issues appeared on subjects such as particle physics, Stanislaw Ulam, and the Human Genome Project. "Pedagogical articles" were intended to explain difficult concepts in one field to scientists and students in other fields. References Science and technology magazines published in the United States Magazines established in 1980 Magazines disestablished in 2005 Defunct magazines published in the United States Biannual magazines published in the United States Magazines published in New Mexico Physics magazines {{science-journal-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Clementine (nuclear Reactor)
Clementine was the code name for the world's first continuous fast-neutron reactor, also known as the Los Alamos fast plutonium reactor. It was an experimental-scale reactor. The maximum output was 25 kW and was fueled by plutonium and cooled by liquid mercury (element), mercury. Clementine was located at Los Alamos National Laboratory in Los Alamos, New Mexico. Clementine was designed and built in 1945–1946 and first achieved criticality in 1946 and full power in March 1949. The reactor was named after the song "Oh My Darling, Clementine." The similarities to the song were that the reactor was located in a deep canyon and the reactor operators were 49'ers, as 49 (last digits of element 94, isotope 239) was one of the code names for plutonium at the time. The primary goal of Clementine was to determine nuclear properties of materials for nuclear weapons research after the Manhattan project. A number of other experiments were performed at the reactor, including investiga ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lead-bismuth Eutectic
Lead-bismuth eutectic or LBE is a eutectic alloy of lead (44.5 at%) and bismuth (55.5 at%) used as a coolant in some nuclear reactors, and is a proposed coolant for the lead-cooled fast reactor, part of the Generation IV reactor initiative. It has a melting point of 123.5 °C/254.3 °F (pure lead melts at 327 °C/621 °F, pure bismuth at 271 °C/520 °F) and a boiling point of 1,670 °C/3,038 °F. Lead-bismuth alloys with between 30% and 75% bismuth all have melting points below 200 °C/392 °F. Alloys with between 48% and 63% bismuth have melting points below 150 °C/302 °F. While lead expands slightly on melting and bismuth contracts slightly on melting, LBE has negligible change in volume on melting. History The Soviet Alfa-class submarines used LBE as a coolant for their nuclear reactors throughout the Cold War. OKB Gidropress (the Russian developers of the VVER-type Light-water reactors) has expertise in LBE ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lead
Lead () is a chemical element; it has Chemical symbol, symbol Pb (from Latin ) and atomic number 82. It is a Heavy metal (elements), heavy metal that is density, denser than most common materials. Lead is Mohs scale, soft and Ductility, malleable, and also has a relatively low melting point. When freshly cut, lead is a shiny gray with a hint of blue. It tarnishes to a dull gray color when exposed to air. Lead has the highest atomic number of any stable nuclide, stable element and three of its isotopes are endpoints of major nuclear decay chains of heavier elements. Lead is a relatively unreactive post-transition metal. Its weak metallic character is illustrated by its Amphoterism, amphoteric nature; lead and lead oxides react with acids and base (chemistry), bases, and it tends to form covalent bonds. Lead compounds, Compounds of lead are usually found in the +2 oxidation state rather than the +4 state common with lighter members of the carbon group. Exceptions are mostly limited ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sodium
Sodium is a chemical element; it has Symbol (chemistry), symbol Na (from Neo-Latin ) and atomic number 11. It is a soft, silvery-white, highly reactive metal. Sodium is an alkali metal, being in group 1 element, group 1 of the periodic table. Its only stable isotope is 23Na. The free metal does not occur in nature and must be prepared from compounds. Sodium is the Abundance of elements in Earth's crust, sixth most abundant element in the Earth's crust and exists in numerous minerals such as feldspars, sodalite, and halite (NaCl). Many salts of sodium are highly water-soluble: sodium ions have been Leaching (chemistry), leached by the action of water from the Earth, Earth's minerals over eons, and thus sodium and chlorine are the most common dissolved elements by weight in the oceans. Sodium was first isolated by Humphry Davy in 1807 by the electrolysis of sodium hydroxide. Among many other useful sodium compounds, sodium hydroxide (lye) is used in Soap, soap manufac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
