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Topic: Nuclear reactor


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In the News (Mon 12 Nov 18)

  
  Nuclear reactor - Wikipedia, the free encyclopedia
A nuclear reactor is a device in which nuclear chain reactions are initiated, controlled, and sustained at a steady rate (as opposed to a nuclear explosion, where the chain reaction occurs in a split second).
The concept of a natural nuclear reactor was theorized as early as 1956 by Paul Kuroda at the University of Arkansas [1].
The fraction of the reactor's fuel core replaced during refueling is typically one-fourth for a boiling-water reactor and one-third for a pressurized-water reactor.
en.wikipedia.org /wiki/Nuclear_reactor   (3398 words)

  
 nuclear reactor. The Columbia Encyclopedia, Sixth Edition. 2001-05
A nuclear reactor is sometimes called an atomic pile because a reactor using graphite as a moderator consists of a pile of graphite blocks with rods of uranium fuel inserted into it.
Reactors in which the uranium rods are immersed in a bath of heavy water are often referred to as “swimming-pool” reactors.
In a fusion reactor, the principal problem is the containment of the plasma fuel, which must be at a temperature of millions of degrees in order to initiate the reaction.
www.bartleby.com /65/nu/nuclreac.html   (923 words)

  
 Nuclear reactor   (Site not responding. Last check: 2007-10-21)
Nuclear reactors are used for providing heat for electricity generation, domestic and industrial heating, desalination, and naval propulsion, for providing neutron beams for research purposes, and for making radioactive isotopes.
Although the majority of nuclear reactors exist to produce useful energy for the generation of electricity, some are used for research, the production of radioactive isotopes for medical and industrial use, and/or the production of plutonium for nuclear weapons.
Additional reactors were used in the navy (United States Naval reactor) In the mid-1950s, both the Soviet Union and western countries were expanding their nuclear research to include non-military uses of the atom.
usapedia.com /n/nuclear-reactor.html   (2566 words)

  
 Nuclear Energy is the most certain future source.   (Site not responding. Last check: 2007-10-21)
A nuclear reactor engine that would provide the right amount of energy for a car could be built and would run fine and would require refuelling only every 5 or 10 years.
Nuclear reactors produce plutonium, and plutonium is terrible because it can be used to make bombs.
Nuclear reactors are likely to have accidents with severe consequences for humanity.
www-formal.stanford.edu /jmc/progress/nuclear-faq.html   (5220 words)

  
 World Nuclear Association | Information and Issue Briefs | Chernobyl Accident
The April 1986 disaster at the Chernobyl nuclear power plant in the Ukraine was the product of a flawed Soviet reactor design coupled with serious mistakes made by the plant operators in the context of a system where training was minimal.
When it was announced in 1995 that the two operating reactors at Chernobyl would be closed by 2000, a memorandum of understanding was signed by Ukraine and G7 nations to progress this, but its implementation was conspicuously delayed.
All of the RBMK reactors have now been modified by changes in the control rods, adding neutron absorbers and consequently increasing the fuel enrichment from 1.8 to 2.4% U-235, making them very much more stable at low power.
www.world-nuclear.org /info/chernobyl/inf07.htm   (2898 words)

  
 Nuclear reactor
Obviously, the number of neutrons present in the reactor must be regulated or controlled since this determines the rate of fission and thus the energy released per second.
The temperature changes in turn modify the reactivity through different nuclear physics processes, which has a well defined influence on the number of neutrons ready to induce fission and thus on power.
In terms of reactor safety it is an obvious intention that all feedbacks should be negative.
www.npp.hu /mukodes/lancreakcio-e.htm   (1091 words)

  
 Bushehr - Iran Nuclear Reactor
Nuclear power industry contacts between Iran and Russia are based on the intergovernmental agreements of 25 August 1992, on cooperation in the civil use of nuclear energy and in the construction of a nuclear power plant in Iran.
The Bushehr nuclear power plant was to come on line during the "latter part" of the next Iranian year that begins on 21 March 2003, its manager Nasser Shariflu told the Persian daily "Iran" on 11 March.
According to Paul Leventhal of the Nuclear Control Institute, if Iran were to withdraw from the Nonproliferation Treaty and renounce the agreement with Russia, the Bushehr reactor could produce a quarter ton of plutonium per year, which Leventhal says is enough for at least 30 atomic bombs.
www.globalsecurity.org /wmd/world/iran/bushehr.htm   (3374 words)

  
 Researchers describe how natural nuclear reactor worked
Prior to this calculation, it was known that the natural nuclear reactor operated two billion years ago for 150 million years at an average power of 100 kilowatts.
As the temperature of the reactor went up, water was converted to steam, reducing the neutron thermalisation and shutting down the chain reaction.
Another vital condition for self-sustaining nuclear reaction is the high content of a moderator to slow the neutrons, Meshik said.
www.eurekalert.org /pub_releases/2004-10/wuis-rdh102804.php   (911 words)

  
 Natural Nuclear Reactors (Oklo)
The impression has been given that to design and construct a nuclear reactor is a feat unique to physical science and engineering creativity.
It is chastening to find that, in the Proterozoic, an unassertive community of modest bacteria built a set of nuclear reactors that ran for millions of years.
The fact that the reactors ran so long and that there was more than one of them suggests that replenishment must have occured and that the radiation and nuclear waste from the reactor was not a deterrent to that ancient bacterial ecosystem.
www.alamut.com /proj/98/nuclearGarden/bookTexts/Lovelock_Oklo.html   (922 words)

  
 Nuclear Reactor at the University of Missouri-Rolla
The UNIVERSITY OF MISSOURI-ROLLA (UMR) reactor has been in operation since 1961 and was the first nuclear reactor in the state of Missouri.
The reactor facility is available for use by students, faculty, and outside researchers.
Use of the reactor by both college and high school students outside of the university is strongly encouraged.
www.nuc.umr.edu /reactor/reactor.html   (839 words)

  
 BBC ON THIS DAY | 7 | 1981: Israel bombs Baghdad nuclear reactor
The 70-megawatt uranium-powered reactor was near completion but had not been stocked with nuclear fuel so there was no danger of a leak, according to sources in the French atomic industry.
The Osirak reactor is part of a complex that includes a second, smaller reactor - also French-built - and a Soviet-made test reactor already in use.
And in 1986, Mordechai Vanunu, a former nuclear technician was found guilty of espionage after he told a British newspaper, the Sunday Times, that Israel was secretly building atomic bombs.
news.bbc.co.uk /onthisday/hi/dates/stories/june/7/newsid_3014000/3014623.stm   (505 words)

  
 National Policy Analysis #378: Integral Fast Reactors: Source of Safe, Abundant, Non-Polluting Power - December 2001
A thermal reactor is a net burner of nuclear fuel, but - and this is very important - all thermal reactors are prolific breeders of plutonium.
Partly for historical reasons (originally, fast reactors were investigated because of their potential to breed), partly because of genuine confusion, and partly for the emotional impact, since "breeder" carries the subliminal connotation of runaway plutonium production.
In December, 1995, at the Monju reactor, a temperature sensor broke and sodium leaked from a secondary sodium loop and caught fire.
www.nationalcenter.org /NPA378.html   (4302 words)

  
 Reed Research Reactor
The Reed College Reactor Facility was established in 1968 and is the only reactor operated primarily by undergraduates.
In addition to operating the reactor, many students serve as senior staff and in supervisory positions.
The Reactor Seminars are on Mondays at 7:30 pm in Psych-105.
reactor.reed.edu   (202 words)

  
 kernenergie.de - Informationen über Kernenergie, Atomkraft, Zwischenlager, Kernkraftwerk, Wiederaufbereitung   (Site not responding. Last check: 2007-10-21)
There are two kinds of neutrons: fast ones (red dots), which are liberated during the fission of a uranium nucleus, and thermal ones, which are the result of a collision of a fast neutron with a hydrogen nucleus of a water molecule.
The other two neutrons either leave the reactor or are absorbed in the control rods or even by the moderator.
An example of a reactor that disposes of a moderator draining system for fast shut-down is the training reactor of the University in Zittau, the so-called Zittauer Lehr- und Forschungsreaktor (ZLFR) (in German).
www.kernenergie.net /datf/en/interactive/reactor.php   (1855 words)

  
 Oklo: Natural Nuclear Reactors - Fact Sheet
Once the natural reactors burned themselves out, the highly radioactive waste they generated was held in place deep under Oklo by the granite, sandstone, and clays surrounding the reactors’ areas.
Scientists involved in the disposal of nuclear waste are very interested in Oklo because long-lived wastes created there remain close to their place of origin.
But nearly two billion years ago, nature not only appears to have created her first nuclear reactors, she also found a way to successfully contain the waste they produced deep underground.
www.ocrwm.doe.gov /factsheets/doeymp0010.shtml   (1227 words)

  
 End the nuclear threat | Greenpeace International   (Site not responding. Last check: 2007-10-21)
Nuclear installations, whether military or civil, have a sad record of accidents and incidents, shrouded in cover-ups, lies and misinformation.
The generation of electricity in nuclear reactors produces substances than can be used for the fabrication of nuclear weapons.
The Greenpeace sampling operation of October 2005, was concentrated in the area west from the Chernobyl reactor outside the so-called 'exclusion zone' at publically accessible territory.
www.greenpeace.org /international/campaigns/nuclear   (596 words)

  
 University of Wisconsin Nuclear Reactor Laboratory: Neutron Activation Analysis Service, Training, Reactor Sharing ...
The Reactor Lab maintains an open and welcoming enviroment to the general public and the community around it.
Nuclear science education for close to 800 general public individuals in the form of tours, demonstratins, and science experiments.
A Research Reactor Training program was developed, and has been used by utilities from several states as part of training programs for operators, senior operators, and shift technical advisors.
reactor.engr.wisc.edu   (532 words)

  
 Accelerator-driven systems
In such a subcritical nuclear reactor the neutrons produced by spallation would be used to cause fission in the fuel, assisted by further neutrons arising from that fission.
One then has a nuclear reactor which could be turned off simply by stopping the proton beam, rather than needing to insert control rods to absorb neutrons and make the fuel assembly subcritical.
Therefore in principle, the subcritical nuclear reactor may be able to convert all transuranic elements into (generally) short-lived fission products and yield some energy in the process.
www.uic.com.au /nip47.htm   (1451 words)

  
 adn.com | front : Village invited to test cheap, clean nuclear power   (Site not responding. Last check: 2007-10-21)
The Galena design is part of a new generation of small nuclear reactors that can be built in a factory and transported by barge, truck or helicopter.
The nuclear reaction is controlled by a reflector that slowly slides over the uranium core and keeps the nuclear fission "critical." If the reflector stops moving, the reactor loses power.
The nuclear reaction heats liquid sodium in the upper portion of the reactor assembly.
www.adn.com /front/story/4214182p-4226215c.html   (1831 words)

  
 The Pulse of a Nuclear Reactor
In 1956, nuclear chemist Paul Kazuo Kuroda of the University of Arkansas in Fayetteville predicted that a chain reaction could develop in natural uranium deposits, generating heat just as the reactor in a nuclear power plant does.
The relative concentrations of the isotopes in the natural reactor differed from those produced in a continuous chain reaction, Meshik and his colleagues observed.
So if the phosphate crystals formed only when the reactor was dormant and cooling, they would capture fewer of the fast-emerging isotopes, which had already diffused away, and more of the slowly emerging ones.
focus.aps.org /story/v14/st18   (639 words)

  
 Nuclear Power Reactors   (Site not responding. Last check: 2007-10-21)
In a nuclear power plant, the fission of Uranium atoms in the reactor provides the heat to produce steam for generating electricity.
Heat is produced in a nuclear reactor when neutrons strike Uranium atoms causing them to fission in a continuous chain reaction.
In a PWR, the heat is removed from the reactor by water flowing in a closed pressurized loop.
reactor.engr.wisc.edu /power.html   (433 words)

  
 The Nuclear Reactor at UCI   (Site not responding. Last check: 2007-10-21)
The reactor is a 250 kilowatt steady-state power Mark I TRIGA reactor built by General Atomics.
TRIGA reactors are water and zirconium hydride moderated to be especially safe for training and research purposes.
The services of the reactor and radiochemistry analysis equipment are also available to other educational institutions for class use free of charge (supported by a Department of Energy grant) and for research or business use at fixed costs.
chem.ps.uci.edu /~gemiller/reactor.html   (579 words)

  
 Nuclear reactor - [Sunday Herald]   (Site not responding. Last check: 2007-10-21)
The expense of nuclear is nothing compared to the cost of losing civilisation to rising flood waters, while the dangers are a figment of our fearful imaginations.
In 2003, he rocked the environmental world with a clarion call for nuclear power published in The Independent newspaper, which made “nuclear” palatable as a word if not a policy, and has helped the Blair government articulate the case for a new generation of nuclear power stations.
Even with the Chernobyl nuclear reactor fire, deaths were limited to 75, mostly among those who extinguished it.
www.sundayherald.com /53996   (1256 words)

  
 deseretnews.com | Fun with fusion: Freshman's nuclear fusion reactor has USU physics faculty in awe
The apparatus is nothing less than the sine qua non of modern science: a nuclear fusion reactor, based on the plans of Utah's own Philo Farnsworth, the inventor of television.
The reactor sat on a table with an attached vacuum pump wheezing away.
One professor Friday stood nervously away from Wallace's reactor — which is notably free from any shielding — but he needn't have worried: Wallace's detector measures 36 neutrons per minute just in background radiation from space, and the device's usual output adds only four neutrons per minute.
deseretnews.com /dn/view/0,1249,510054502,00.html   (760 words)

  
 Cambridge evaluates MIT's nuclear reactor
In addition, the core of the reactor, the unit in which nuclear reactions take place, is further surrounded by a five-foot concrete enclosure, Clark said.
The special training, which is jointly designed by reactor officials and the MIT police chief, mainly focuses on the safe handling of radioactive material, he added.
The MIT reactor is used for a wide range of research experiments in fields such as medicine, geology, nuclear physics, and radiochemistry, Clark described.
www-tech.mit.edu /V105/N59/nucle.59n.html   (1230 words)

  
 Osiraq - Iraq Special Weapons Facilities
Iraq began to expand its nuclear sector in the 1970's, but made little progress in the early 1980's, when most of its energy and attention were focused on the war against Iran.
IAEA officials denied these charges and reaffirmed their position on the Iraqi reactor, that is, that no weapons had been manufactured at Osiraq and that Iraqi officials had regularly cooperated with agency inspectors.
The Israeli nuclear facility at Dimona, it was pointed out, was not under IAEA safeguards, because Israel had not signed the NPT and had refused to open its facilities to UN inspections.
www.fas.org /nuke/guide/iraq/facility/osiraq.htm   (1270 words)

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