Three Mile Island Accident
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Three Mile Island Accident
The Three Mile Island accident was a partial nuclear meltdown of the Unit 2 reactor (TMI-2) of the Three Mile Island Nuclear Generating Station, located on the Susquehanna River in Londonderry Township, Dauphin County, Pennsylvania, Londonderry Township near Harrisburg, Pennsylvania. The reactor accident began at 4:00 a.m. on March 28, 1979, and released Radioactive decay, radioactive gases and radioactive iodine-131, iodine into the environment. It is the worst accident in U.S. commercial nuclear power plant history. On the seven-point Logarithmic scale, logarithmic International Nuclear Event Scale, the TMI-2 reactor accident is rated Level5, an "Accident with Wider Consequences". The accident began with failures in the non-nuclear secondary system, followed by a stuck-open pilot-operated relief valve (PORV) in the primary system, which allowed large amounts of water to escape from the pressurized isolated coolant loop. The mechanical failures were compounded by the in ...
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Eastern Time Zone
The Eastern Time Zone (ET) is a time zone encompassing part or all of 23 U.S. states, states in the eastern part of the United States, parts of eastern Canada, and the state of Quintana Roo in Mexico. * Eastern Standard Time (EST) is five hours behind Coordinated Universal Time (UTC−05:00). Observed during standard time (late autumn/winter in the United States and Canada). * Eastern Daylight Time (EDT) is four hours behind Coordinated Universal Time (UTC−04:00). Observed during daylight saving time (spring/summer/early autumn in the United States and Canada). On the second Sunday in March, at 2:00 a.m. EST, clocks are advanced to 3:00 a.m. EDT, creating a 23-hour day. On the first Sunday in November, at 2:00 a.m. EDT, clocks are moved back to 1:00 a.m. EST, which results in a 25-hour day. History The boundaries of the Eastern Time Zone have moved westward since the Interstate Commerce Commission (ICC) took over time-zone management from railroads in ...
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Anti-nuclear Movement
The Anti-nuclear war movement is a new social movements, social movement that opposes various nuclear technology, nuclear technologies. Some direct action groups, environmental movements, and professional organisations have identified themselves with the movement at the local, national, or international level.Fox ButterfieldProfessional Groups Flocking to Antinuclear Drive, ''The New York Times'', 27 March 1982. Major List of anti-nuclear groups, anti-nuclear groups include Campaign for Nuclear Disarmament, Friends of the Earth, Greenpeace, International Physicians for the Prevention of Nuclear War, Peace Action, Seneca Women's Encampment for a Future of Peace and Justice and the Nuclear Information and Resource Service. The initial objective of the movement was nuclear disarmament, though since the late 1960s opposition has included the use of nuclear power. Many anti-nuclear groups oppose both nuclear power and nuclear weapons. The formation of green party, green parties i ...
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Turbine Trip
A turbine trip is the automatic safety shutdown of a power-generation turbine due to unexpected events. Due to the number of issues that may cause a trip, they are relatively common events. The term is common in both coal and 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 ... generation. Many events can cause a turbine trip, including: * turbine overspeed condition where the turbine accelerates over its design speed, typically by 10% * low vacuum in the secondary cooling loop, or condenser * lubrication failure for any number of reasons * vibrations due to any number of issues In order to trip the turbine, inlet steam must be removed from the feed. This is normally accomplished with dump valves that re-route the feed steam from the turbine inlet directly into the c ...
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Feedwater Pump
A boiler feedwater pump is a specific type of pump used to pump feedwater into a steam boiler. The water may be freshly supplied or returning condensate produced as a result of the condensation of the steam produced by the boiler. These pumps are normally high pressure units that take suction from a condensate return system and can be of the centrifugal pump type or positive displacement type. Construction and operation Feedwater pumps range in size up to many kilowatts and the electric motor is usually separated from the pump body by some form of mechanical coupling. Large industrial condensate pumps may also serve as the feedwater pump. In either case, to force the water into the boiler, the pump must generate sufficient pressure to overcome the steam pressure developed by the boiler. This is usually accomplished through the use of a centrifugal pump. Another common form of feedwater pump runs constantly and is provided with a minimum flow device to stop overpressuring the ...
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Air Line
An air line is a tube, or hose, that contains and carries a compressed air supply. In industrial usage, this may be used to inflate car or bicycle tyres or power tools worked by compressed air, for breathing apparatus in hazardous environments and to operate many other pneumatic systems. Air lines provide compressed air for a wide range of uses and to cater for a variety of uses air lines are manufactured in a range of corrosion-resistant materials. Typically air lines are made with flexible hose or rigid pipe. Air line hoses provide flexibility and mobility for use, whereas a piped air line is more permanent and resistant to damage. For a typical compressed air system, both types of air lines are used in conjunction. Air line hose Air line hoses are flexible tubes used to convey pressurised air. They are commonly used for carrying a supply of compressed air to operate pneumatic powered systems, such as a road vehicle air brake system for large vehicles and a railway air brak ...
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Condensate Polisher
A condensate polisher is a device used to filter water condensed from steam as part of the steam cycle, for example in a conventional or nuclear power plant (powdered resin or deep bed system). It is frequently filled with tiny polymer resin beads which are used to remove or exchange ions so that the purity of the condensate is maintained at or near that of distilled water. __TOC__ Description Condensate polishers are important in systems using the boiling and condensing of water to transport or transform thermal energy. Using technology similar to a water softener, trace amounts of minerals or other contamination are removed from the system before such contamination becomes concentrated enough to cause problems by depositing minerals inside pipes, or within precision-engineered devices such as boilers, steam generators, heat exchangers, steam turbines, cooling towers, and condensers. The removal of minerals has the secondary effect of maintaining the pH balance of the water a ...
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Pressurized Water Reactor
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 (with notable exceptions being the UK, Japan, India and Canada). In a PWR, water is used both as a neutron moderator and as coolant fluid for the reactor core. In the core, water is heated by the energy released by the fission of atoms contained in the fuel. Using very high pressure (around 155 bar: 2250 psi) ensures that the water stays in a liquid state. The heated water then flows to a steam generator, where it transfers its thermal energy to the water of a secondary cycle kept at a lower pressure which allows it to vaporize. The resulting steam then drives steam turbines linked to an electric generator. A boiling water reactor (BWR) by contrast does not maintain such a high pressure in the primary cycle and the water thus vaporizes inside of the reactor pressure vessel (RPV) before being sent to the turbine. Most PWR designs ma ...
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Nuclear Meltdown
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. Once the fuel elements of a reactor b ...
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BBC News
BBC News is an operational business division of the British Broadcasting Corporation (BBC) responsible for the gathering and broadcasting of news and current affairs in the UK and around the world. The department is the world's largest broadcast news organisation and generates about 120 hours of radio and television output each day, as well as online news coverage. The service has over 5,500 journalists working across its output including in 50 foreign news bureaus where more than 250 foreign correspondents are stationed. Deborah Turness has been the CEO of news and current affairs since September 2022. In 2019, it was reported in an Ofcom report that the BBC spent £136m on news during the period April 2018 to March 2019. BBC News' domestic, global and online news divisions are housed within the largest live newsroom in Europe, in Broadcasting House in central London. Parliamentary coverage is produced and broadcast from studios in London. Through BBC English Regions, th ...
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Microsoft
Microsoft Corporation is an American multinational corporation and technology company, technology conglomerate headquartered in Redmond, Washington. Founded in 1975, the company became influential in the History of personal computers#The early 1980s and home computers, rise of personal computers through software like Windows, and the company has since expanded to Internet services, cloud computing, video gaming and other fields. Microsoft is the List of the largest software companies, largest software maker, one of the Trillion-dollar company, most valuable public U.S. companies, and one of the List of most valuable brands, most valuable brands globally. Microsoft was founded by Bill Gates and Paul Allen to develop and sell BASIC interpreters for the Altair 8800. It rose to dominate the personal computer operating system market with MS-DOS in the mid-1980s, followed by Windows. During the 41 years from 1980 to 2021 Microsoft released 9 versions of MS-DOS with a median frequen ...
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Causal
Causality is an influence by which one Event (philosophy), event, process, state, or Object (philosophy), object (''a'' ''cause'') contributes to the production of another event, process, state, or object (an ''effect'') where the cause is at least partly responsible for the effect, and the effect is at least partly dependent on the cause. The cause of something may also be described as the reason for the event or process. In general, a process can have multiple causes,Compare: which are also said to be ''causal factors'' for it, and all lie in its past. An effect can in turn be a cause of, or causal factor for, many other effects, which all lie in its future. Some writers have held that causality is metaphysics , metaphysically prior to notions of time and space. Causality is an abstraction that indicates how the world progresses. As such it is a basic concept; it is more apt to be an explanation of other concepts of progression than something to be explained by other more fun ...
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