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Zirconium is a chemical element; it has symbol Zr and atomic number 40. First identified in 1789, isolated in impure form in 1824, and manufactured at scale by 1925, pure zirconium is a lustrous transition metal with a greyish-white color that closely resembles hafnium and, to a lesser extent, titanium. It is solid at room temperature, ductile, malleable and corrosion-resistant. The name zirconium is derived from the name of the mineral zircon, the most important source of zirconium. The word is related to Persian zargun. Besides zircon, zirconium occurs in over 140 other minerals, including baddeleyite and eudialyte; most zirconium is produced as a byproduct of minerals mined for titanium and tin.
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 loss-of-coolant accident (LOCA) is a mode of failure for a nuclear reactor; if not managed effectively, the results of a LOCA could result in reactor core damage. Each nuclear plant's emergency core cooling system (ECCS) exists specifically to deal with a LOCA.
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.
Passive nuclear safety is a design approach for safety features, implemented in a nuclear reactor, that does not require any active intervention on the part of the operator or electrical/electronic feedback in order to bring the reactor to a safe shutdown state, in the event of a particular type of emergency. Such design features tend to rely on the engineering of components such that their predicted behaviour would slow down, rather than accelerate the deterioration of the reactor state; they typically take advantage of natural forces or phenomena such as gravity, buoyancy, pressure differences, conduction or natural heat convection to accomplish safety functions without requiring an active power source. Many older common reactor designs use passive safety systems to a limited extent, rather, relying on active safety systems such as diesel-powered motors. Some newer reactor designs feature more passive systems; the motivation being that they are highly reliable and reduce the cost associated with the installation and maintenance of systems that would otherwise require multiple trains of equipment and redundant safety class power supplies in order to achieve the same level of reliability. However, weak driving forces that power many passive safety features can pose significant challenges to effectiveness of a passive system, particularly in the short term following an accident.
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. Nuclear fuel has the highest energy density of all practical fuel sources. The processes involved in mining, refining, purifying, using, and disposing of nuclear fuel are collectively known as the nuclear fuel cycle.
A swimming pool reactor, also called an open pool reactor, is a type of nuclear reactor that has a core immersed in an open pool usually of water.
Zirconium alloys are solid solutions of zirconium or other metals, a common subgroup having the trade mark Zircaloy. Zirconium has very low absorption cross-section of thermal neutrons, high hardness, ductility and corrosion resistance. One of the main uses of zirconium alloys is in nuclear technology, as cladding of fuel rods in nuclear reactors, especially water reactors. A typical composition of nuclear-grade zirconium alloys is more than 95 weight percent zirconium and less than 2% of tin, niobium, iron, chromium, nickel and other metals, which are added to improve mechanical properties and corrosion resistance.
Zirconium hydride describes an alloy made by combining zirconium and hydrogen. Hydrogen acts as a hardening agent, preventing dislocations in the zirconium atom crystal lattice from sliding past one another. Varying the amount of hydrogen and the form of its presence in the zirconium hydride controls qualities such as the hardness, ductility, and tensile strength of the resulting zirconium hydride. Zirconium hydride with increased hydrogen content can be made harder and stronger than zirconium, but such zirconium hydride is also less ductile than zirconium.
Nuclear reactor physics is the field of physics that studies and deals with the applied study and engineering applications of chain reaction to induce a controlled rate of fission in a nuclear reactor for the production of energy. Most nuclear reactors use a chain reaction to induce a controlled rate of nuclear fission in fissile material, releasing both energy and free neutrons. A reactor consists of an assembly of nuclear fuel, usually surrounded by a neutron moderator such as regular water, heavy water, graphite, or zirconium hydride, and fitted with mechanisms such as control rods which control the rate of the reaction.
The Saxton Nuclear Experiment Station, also known as the Saxton Nuclear Generating Station or Saxton Nuclear Experimental Corporation Facility, was a small nuclear power plant located in Bedford County, near Saxton, Pennsylvania.
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).
RD-0410 was a Soviet nuclear thermal rocket engine developed by the Chemical Automatics Design Bureau in Voronezh from 1965 through the 1980s using liquid hydrogen propellant. The engine was ground-tested at the Semipalatinsk Test Site, and its use was incorporated in the Kurchatov Mars 1994 crewed mission proposal.
The hydrogen-moderated self-regulating nuclear power module (HPM), also referred to as the compact self-regulating transportable reactor (ComStar), is a type of nuclear power reactor using hydride as a neutron moderator. The design is inherently safe, as the fuel and the neutron moderator is uranium hydride UH3, which is reduced at high temperatures (500–800 °C) to uranium and hydrogen. The gaseous hydrogen exits the core, being absorbed by hydrogen absorbing material such as depleted uranium, thus making it less critical. This means that with rising temperature the neutron moderation drops and the nuclear fission reaction in the core is dampened, leading to a lower core temperature. This means as more energy is taken out of the core the moderation rises and the fission process is stoked to produce more heat.
The Washington State University Reactor (WSUR) is housed in the Dodgen Research Facility, and was completed in 1961. The (then) Washington State College Reactor was the brainchild of Harold W. Dodgen, a former researcher on the Manhattan Project where he earned his PhD from 1943 to 1946. He secured funding for the ambitious 'Reactor Project' from the National Science Foundation, the Atomic Energy Commission, and the College administration totaling $479,000. Dodgen's basis for constructing a reactor was that the College was primely located as a training facility for the Hanford site, as well as Idaho National Laboratory because there was no other research reactor in the West at that time. After completing the extensive application and design process with the help of contractors from General Electric they broke ground in August 1957 and the first criticality was achieved on March 7, 1961 at a power level of 1W. They gradually increased power over the next year to achieve their maximum licensed operating power of 100 kW.
Uranium hydride, also called uranium trihydride (UH3), is an inorganic compound and a hydride of uranium.
FBFC is a nuclear fuel producing company. From 1977 onwards its headquarters are located in Romans-sur-Isère. It operates a further two facilities, one at the Tricastin Nuclear Power Center in France and one Dessel in Belgium. In 2001 FBFC became a wholly owned subsidiary of Areva. Since 2018, FBFC is a subsidiary of Framatome. In Dessel FBFC employs around 150 people.
Edward Creutz was an American physicist who worked on the Manhattan Project at the Metallurgical Laboratory and the Los Alamos Laboratory during World War II. After the war he became a professor of physics at the Carnegie Institute of Technology. He was Vice President of Research at General Atomics from 1955 to 1970. He published over 65 papers on botany, physics, mathematics, metallurgy and science policy, and held 18 patents relating to nuclear energy.
FiR 1 was Finland's first nuclear reactor. It was a research reactor that was located in the Otaniemi campus area in the city of Espoo. The TRIGA Mark II reactor had a thermal power of 250 kilowatts. It started operation in 1962, and it was permanently shut down in 2015. At first, the reactor was operated by Helsinki University of Technology (TKK), and since 1971 by VTT Technical Research Centre of Finland.
