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Reactor Protective System
A reactor protection system (RPS) is a set of nuclear safety and security components in a nuclear power plant designed to safely shut down the reactor and prevent the release of radioactive materials. The system can "trip" automatically (initiating a scram), or it can be tripped by the operators. Trips occurs when the parameters meet or exceed the limit setpoint. A trip of the RPS results in full insertion (by gravity in pressurized water reactors or high-speed injection in boiling water reactors) of all control rods and shutdown of the reactor. Pressurized water reactors Some of the measured parameters for US pressurized water plants would include: *"High power", auctioneered between high nuclear power and high differential temperature (delta T) between the inlet and outlet of the reactor vessel (a measure of the thermal power for a given RCS flowrate). *"High startup rate" (active below 10-4 percent power) at low power levels. *"High pressurizer pressure" *"Low reactor coola ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nuclear Safety And Security
Nuclear safety is defined by the International Atomic Energy Agency (IAEA) as "The achievement of proper operating conditions, prevention of accidents or mitigation of accident consequences, resulting in protection of workers, the public and the environment from undue radiation hazards". The IAEA defines nuclear security as "The prevention and detection of and response to, theft, sabotage, unauthorized access, illegal transfer or other malicious acts involving nuclear materials, other radioactive substances or their associated facilities". This covers nuclear power plants and all other nuclear facilities, the transportation of nuclear materials, and the use and storage of nuclear materials for medical, power, industry, and military uses. The nuclear power industry has improved the safety and performance of reactors, and has proposed new and safer reactor designs. However, a perfect safety cannot be guaranteed. Potential sources of problems include human errors and external e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nuclear Power Plant
A nuclear power plant (NPP) 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. , the International Atomic Energy Agency reported there were 422 nuclear power reactors in operation in 32 countries around the world, and 57 nuclear power reactors under construction. Nuclear plants are very often used for base load since their operations, maintenance, and fuel costs are at the lower end of the spectrum of costs. However, building a nuclear power plant often spans five to ten years, which can accrue to significant financial costs, depending on how the initial investments are financed. Nuclear power plants have a carbon footprint comparable to that of renewable energy such as solar farms and wind farms, and much lower than fossil fuels such as natural gas and brown coal. Despite some spectacu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nuclear Reactor
A nuclear reactor is a device used to initiate and control a fission nuclear chain reaction or nuclear fusion reactions. Nuclear reactors are used at nuclear power plants for electricity generation and in nuclear marine propulsion. Heat from nuclear fission is passed to a working fluid (water or gas), which in turn runs through steam turbines. These either drive a ship's propellers or turn electrical generators' shafts. Nuclear generated steam in principle can be used for industrial process heat or for district heating. Some reactors are used to produce isotopes for medical and industrial use, or for production of weapons-grade plutonium. , the International Atomic Energy Agency reports there are 422 nuclear power reactors and 223 nuclear research reactors in operation around the world. In the early era of nuclear reactors (1940s), a reactor was known as a nuclear pile or atomic pile (so-called because the graphite moderator blocks of the first reactor were placed in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radioactive Decay
Radioactive decay (also known as nuclear decay, radioactivity, radioactive disintegration, or nuclear disintegration) is the process by which an unstable atomic nucleus loses energy by radiation. A material containing unstable nuclei is considered radioactive. Three of the most common types of decay are alpha decay ( ), beta decay ( ), and gamma decay ( ), all of which involve emitting one or more particles. The weak force is the mechanism that is responsible for beta decay, while the other two are governed by the electromagnetism and nuclear force. A fourth type of common decay is electron capture, in which an unstable nucleus captures an inner electron from one of the electron shells. The loss of that electron from the shell results in a cascade of electrons dropping down to that lower shell resulting in emission of discrete X-rays from the transitions. A common example is iodine-125 commonly used in medical settings. Radioactive decay is a stochastic (i.e. random) pro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scram
A scram or SCRAM is an emergency shutdown of a nuclear reactor effected by immediately terminating the fission reaction. It is also the name that is given to the manually operated kill switch that initiates the shutdown. In commercial reactor operations, this type of shutdown is often referred to as a "scram" at boiling water reactors (BWR), a "reactor ''trip''" at pressurized water reactors and at a CANDU reactor. In many cases, a scram is part of the routine shutdown procedure, which serves to test the emergency shutdown system. The etymology of the term is a matter of debate. United States Nuclear Regulatory Commission historian Tom Wellock notes that '' scram'' is English-language slang for leaving quickly and urgently, and cites this as the original and most likely accurate basis for the use of ''scram'' in the technical context. A persistent alternative explanation posits that ''scram'' is an acronym for "safety control rod axe man", which was supposedly coined by Enr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Control Rod
Control rods are used in nuclear reactors to control the rate of fission of the nuclear fuel – uranium or plutonium. Their compositions include chemical elements such as boron, cadmium, silver, hafnium, or indium, that are capable of absorbing many neutrons without themselves decaying. These elements have different neutron capture cross sections for neutrons of various energies. Boiling water reactors (BWR), pressurized water reactors (PWR), and heavy-water reactors (HWR) operate with thermal neutrons, while breeder reactors operate with fast neutrons. Each reactor design can use different control rod materials based on the energy spectrum of its neutrons. Control rods have been used in nuclear aircraft engines like Project Pluto as a method of control. Operating principle Control rods are inserted into the core of a nuclear reactor and adjusted in order to control the rate of the nuclear chain reaction and, thereby, the thermal power output of the reactor, the rat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nuclear Power
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''. Generating electricity from ''fusion'' power remains the focus of international research. Most nuclear power plants use thermal reactors with enriched uranium in a once-through fuel cycle. Fuel is removed when the percentage of neutron absorbing atoms becomes so large that a chain reaction can no longer be sustained, typically three years. It is then cooled for several years in on-site spent fuel pools before being transferred to long term storage. The spent fuel, though low in volume, is high-level radioactive wa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nuclear Safety And Security
Nuclear safety is defined by the International Atomic Energy Agency (IAEA) as "The achievement of proper operating conditions, prevention of accidents or mitigation of accident consequences, resulting in protection of workers, the public and the environment from undue radiation hazards". The IAEA defines nuclear security as "The prevention and detection of and response to, theft, sabotage, unauthorized access, illegal transfer or other malicious acts involving nuclear materials, other radioactive substances or their associated facilities". This covers nuclear power plants and all other nuclear facilities, the transportation of nuclear materials, and the use and storage of nuclear materials for medical, power, industry, and military uses. The nuclear power industry has improved the safety and performance of reactors, and has proposed new and safer reactor designs. However, a perfect safety cannot be guaranteed. Potential sources of problems include human errors and external e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Generation III Reactor
Generation III reactors, or Gen III reactors, are a class of nuclear reactors designed to succeed Generation II reactors, incorporating evolutionary improvements in design. These include improved fuel technology, higher thermal efficiency, significantly enhanced safety systems (including passive nuclear safety), and standardized designs intended to reduce maintenance and capital costs. They are promoted by the Generation IV International Forum (GIF). The first Generation III reactors to begin operation were Kashiwazaki 6 and 7 advanced boiling water reactors (ABWRs) in 1996 and 1997. Since 2012, both have been shut down due to security concerns. Due to the prolonged period of stagnation in the construction of new reactors and the continued (albeit declining) popularity of Generation II/II+ designs in new construction, relatively few third generation reactors have been built. Overview The older Gen II reactors comprise the vast majority of current nuclear reactors. Gen III r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Generation IV Reactor
Generation IV reactors (Gen IV) are six nuclear reactor designs recognized by the Generation IV International Forum. The designs target improved safety, sustainability, efficiency, and cost. The most developed Gen IV reactor design is the sodium fast reactor. It has received the greatest share of funding that supports demonstration facilities, as well as two commercial reactors in Russia. One of these has been in commercial operation since 1981. Its principal Gen IV features relates its sustainable closed fuel cycle. Moir and Teller consider the molten-salt reactor, a less developed technology, as potentially having the greatest inherent safety of the six models. The very-high-temperature reactor designs operate at much higher temperatures than prior generations. This allows for high temperature electrolysis or for sulfur–iodine cycle for the efficient production of hydrogen and the synthesis of carbon-neutral fuels. The first commercial plants are not expected before 2040 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nuclear Power Plant Components
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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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
