Core of a nuclear reactor

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). Nuclear reactors are used for many purposes, but the most significant current uses are for the generation of electrical power and, in rare cases, for the production of plutonium for use in nuclear weapons. Currently all commercial nuclear reactors are based on nuclear fission, and are considered problematic by some for their safety and health risks. Conversely, some consider nuclear power to be a safe and pollution-free method of generating electricity. Fusion power is an experimental technology based on nuclear fusion instead of fission. Image File history File links Download high resolution version (2560x1920, 798 KB) Réacteur CROCUS; expérience CAROUSEL; divers expériences et manips; détecteurs et instruments. ... Image File history File links Download high resolution version (2560x1920, 798 KB) Réacteur CROCUS; expérience CAROUSEL; divers expériences et manips; détecteurs et instruments. ... Albert Einsteins letter to President Roosevelt in 1939 about his concern, about (Nuclear chain reactions) Click for closeup of letter A nuclear chain reaction occurs when on average more than one nuclear reaction is caused by another nuclear reaction, thus leading to an exponential increase in the number of... A 23 kiloton tower shot called BADGER, fired on April 18, 1953 at the Nevada Test Site, as part of the Operation Upshot-Knothole nuclear test. ... Transmission lines in Lund, Sweden Electric power, often known as power or electricity, involves the production and delivery of electrical energy in sufficient quantities to operate domestic appliances, office equipment, industrial machinery and provide sufficient energy for both domestic and commercial lighting, heating, cooking and industrial processes. ... General Name, Symbol, Number plutonium, Pu, 94 Chemical series actinides Group, Period, Block ?, 7, f Appearance silvery white Atomic mass (244) g/mol Electron configuration [Rn] 5f6 7s2 Electrons per shell 2, 8, 18, 32, 24, 8, 2 Physical properties Phase solid Density (near r. ... The mushroom cloud of the atomic bombing of Nagasaki, Japan, 1945, rose some 18 km (11 mi) above the hypocenter. ... Sketch of induced nuclear fission, a neutron (n) strikes a uranium nucleus which splits into similar products (F. P.), and releases more neutrons to continue the process, and energy in the form of gamma and other radiation. ... The Sun is a natural fusion reactor. ... The deuterium-tritium fusion reaction is considered the most promising for producing fusion power. ...

There are other devices in which nuclear reactions occur in a controlled fashion, including radioisotope thermoelectric generators, which generate heat and power by passive radioactive decay, and Farnsworth-Hirsch fusors, in which controlled nuclear fusion is used to produce neutron radiation. A radioisotope thermoelectric generator (RTG) is a simple electrical generator which obtains its power from radioactive decay. ... US3386883 - fusor -- June 4, 1968 The Farnsworth-Hirsch Fusor, or simply fusor, is an apparatus designed by Philo T. Farnsworth to create nuclear fusion. ... Neutron radiation consists of free neutrons. ...

A nuclear power station. The nuclear reactors are inside the two cylindrical containment buildings in the foreground—behind are the cooling towers (venting water vapor).

Image File history File links Nuclear_powerplant-01. ... Image File history File links Nuclear_powerplant-01. ... A containment building, in its most common usage, is a steel or concrete structure enclosing a nuclear reactor. ...

Applications

• Nuclear power:
  • heat for electricity generation
  • heat for domestic and industrial heating
  • desalination
• Nuclear propulsion:
  • nuclear marine propulsion
  • proposed nuclear thermal rockets
• Transmutation of elements:
  • production of plutonium, often for use in nuclear weapons
  • creating various radioactive isotopes, such as americium for use in smoke detectors
• research applications including:
  • providing a source of neutron and positron radiation
  • development of nuclear technology

This article is about power derived from nuclear reactions. ... Itaipu Dam is a hydroelectric generating station Electricity generation is the first process in the delivery of electricity to consumers. ... HVAC may also stand for High-voltage alternating current HVAC is an initialism that stands for heating, ventilation and air-conditioning. This is sometimes referred to as climate control. ... Desalination refers to any of several processes that remove the excess salt and other minerals from water in order to obtain fresh water suitable for animal consumption or irrigation, and if almost all of the salt is removed, for human consumption, sometimes producing table salt as a by-product. ... Nuclear propulsion can include a wide variety of methods, the commonality of which is the use of some form of nuclear reaction as their primary power source. ... Nuclear marine propulsion is propulsion of a Merchant ship powered by a nuclear reactor. ... In a nuclear thermal rocket a working fluid, usually hydrogen, is heated in a high temperature nuclear reactor, and then expands through a rocket nozzle to create thrust. ... Transmutation is the conversion of one object into another. ... General Name, Symbol, Number plutonium, Pu, 94 Chemical series actinides Group, Period, Block ?, 7, f Appearance silvery white Atomic mass (244) g/mol Electron configuration [Rn] 5f6 7s2 Electrons per shell 2, 8, 18, 32, 24, 8, 2 Physical properties Phase solid Density (near r. ... The mushroom cloud of the atomic bombing of Nagasaki, Japan, 1945, rose some 18 km (11 mi) above the hypocenter. ... Radiation has a variety of different meanings. ... Isotopes are forms of an element whose nuclei have the same atomic number–-the number of protons in the nucleus--but different atomic masses because they contain different numbers of neutrons. ... General Name, Symbol, Number americium, Am, 95 Chemical series actinides Group, Period, Block ?, 7, f Appearance silvery white Atomic mass (243) g/mol Electron configuration [Rn] 5f7 7s2 Electrons per shell 2, 8, 18, 32, 25, 8, 2 Physical properties Phase solid Density (near r. ... Residential ceiling-mounted smoke detector A smoke detector (sometimes called a smoke alarm) is a safety device that detects airborne smoke and issues an audible alarm, thereby alerting nearby people to the danger of fire. ... Research is an active, diligent, and systematic process of inquiry in order to discover, interpret or revise facts, events, behaviours, or theories, or to make practical applications with the help of such facts, laws, or theories. ... Positron radiation is a form of beta decay that occurs when a proton changes into a neutron and a positron. ... NUCLEAR TECHNOLOGI ------------------ Nuclear technology is technology that involves the reactions of atomic nuclei. ...

History

Enrico Fermi and Leó Szilárd, while both were at the University of Chicago, were the first to build a nuclear pile and demonstrate a controlled chain reaction on December 2, 1942. In 1955 they shared US patent number 2,708,656 for the nuclear reactor. Enrico Fermi in the 1940s. ... Leó Szilárd (right) and Albert Einstein re-enact the signing of the famous letter to Franklin Delano Roosevelt. ... The University of Chicago is a private co-educational university located in Chicago, Illinois. ... On December 2, 1942, the worlds first self-sustaining nuclear chain reaction, Chicago Pile-1, took place on a squash court beneath Stagg Field on the University of Chicago campus. ... December 2 is the 336th day (337th in leap years) of the year in the Gregorian calendar. ... This article is about the year. ... 1955 (MCMLV) was a common year starting on Saturday of the Gregorian calendar. ... The United States Patent and Trademark Office (PTO or USPTO) is an agency in the United States Department of Commerce that provides patent and trademark protection to inventors and businesses for their inventions and corporate and product identification. ...

The first nuclear reactors were used to generate plutonium for nuclear weapons. Additional reactors were used in the navy (see United States Naval reactor) to propel submarines and aircraft carriers. In the mid-1950s, both the Soviet Union and western countries were expanding their nuclear research to include non-military uses of the atom. However, as with the military program, much of the non-military work was done in secret. On December 20, 1951, electric power from a nuclear powered generator was produced for the first time at Experimental Breeder Reactor-I (EBR-1) located near Arco, Idaho. On June 27, 1954, the world's first nuclear power plant generated electricity but no headlines--at least, not in the West. According to the Uranium Institute (London, England), the first reactor to generate electricity for commercial use was at Obninsk, Kaluga Oblast, Russia. The Shippingport Reactor (in Pennsylvania) was the first commercial nuclear generator to become operational in the United States. The Shippingport reactor was ordered in 1953 and began commercial operation in 1957. United States Naval reactors are given three-character designations consisting of a letter representing the ship type the reactor is designed for, a consecutive generation number, and a letter indicating the reactors designer. ... Royal Navy Vanguard class submarine A submarine is a specialized watercraft that can operate underwater. ... An aircraft carrier is a warship whose main role is to deploy and recover aircraft—in effect acting as a sea-going airbase. ... // Events and trends The 1950s in Western society was marked with a sharp rise in the economy for the first time in almost 30 years and return to the 1920s-type consumer society built on credit and boom-times, as well as the height of the baby boom from returning... December 20 is the 354th day of the year (355th in leap years) in the Gregorian calendar. ... 1951 (MCMLI) was a common year starting on Monday; see its calendar. ... Experimental Breeder Reactor Number 1 in Idaho, the birthplace of atomic energy. ... Arco, Idaho Arco is a city located in Butte County, Idaho. ... June 27 is the 178th day of the year (179th in leap years) in the Gregorian calendar, with 187 days remaining. ... 1954 (MCMLIV) was a common year starting on Friday of the Gregorian calendar. ... Obninsk is a city in Kaluga Oblast of Russia, 100 km south-west of Moscow. ... Kaluga Oblast (Калу́жская о́бласть)(29,900 km², pop. ... The Shippingport reactor was the first full-scale nuclear power plant in the United States. ... 1953 (MCMLIII) is a common year starting on Thursday. ... 1957 (MCMLVII) was a common year starting on Tuesday of the Gregorian calendar. ...

Even before the 1979 Three Mile Island accident, new orders for nuclear plants in the U.S. had ceased for economic reasons primarily related to greatly extended construction times. As of 2004, no new nuclear plants have been ordered in the USA since 1978 [1], although that may change by 2010 (see Future Of The Industry below). This page refers to the year 1979. ... Three Mile Island Nuclear Generating Station consists of two nuclear reactors, each with its own containment building and cooling towers. ... 2004 is a leap year starting on Thursday of the Gregorian calendar. ... 2010 (MMX) is a common year starting on Friday of the Gregorian calendar. ...

Surprisingly, and unlike the Three Mile Island accident, the 1986 Chernobyl accident did not increase regulations affecting Western reactors. This was because the Chernobyl reactors were known to be an unsafe design (RBMKs) without containment buildings and operated unsafely, and the West had nothing to learn from them [2]. There was however political fallout: Italy held a referendum the next year (1987), and it was decided to shut down the country's four nuclear power plants [3]. 1986 (MCMLXXXVI) is a common year starting on Wednesday of the Gregorian calendar. ... The nuclear power plant at Chernobyl prior to the completion of the sarcophagus. ... RBMK is an acronym for the Russian reaktor bolshoi moshchnosty kanalny which means reactor (of) large power (with) channels, and describes a now-obsolete class of nuclear power reactor which was built only in the Soviet Union. ... A containment building, in its most common usage, is a steel or concrete structure enclosing a nuclear reactor. ... 1987 (MCMLXXXVII) is a common year starting on Thursday of the Gregorian calendar. ...

In 1992 the Turkey Point Nuclear Generating Station was hit directly by Hurricane Andrew. Over $90 million of damage was done, largely to a water tank and to a smokestack of one of the fossil-fueled units on-site, but the containment buildings were undamaged [4] [5]. 1992 (MCMXCII) was a leap year starting on Wednesday. ... The twin reactors at Turkey Point nuclear power station are on a 3,300 acre (13 km²) site in Homestead, Florida near Miami, Florida, in Dade County, Florida. ... Hurricane Andrew was one of the most destructive and expensive hurricanes to hit the United States. ... A containment building, in its most common usage, is a steel or concrete structure enclosing a nuclear reactor. ...

The first organization to develop utilitarian nuclear power, the U.S. Navy, is the only organization worldwide with a totally clean record. This is perhaps because of the stringent demands of Admiral Hyman G. Rickover, who was the driving force behind nuclear marine propulsion. The U.S. Navy has operated more nuclear reactors than any other entity, other than the Soviet Navy, with no publicly known major incidents. Two U.S. nuclear submarines, USS Scorpion and Thresher, have been lost at sea, though for reasons not related to their reactors, and their wrecks are situated such that the risk of nuclear pollution is considered low. The United States Navy (USN) is the branch of the United States armed forces responsible for naval operations. ... Hyman George Rickover, M.Sc, (January 27, 1900 - July 8, 1986) was a US Navy Admiral known as the Father of the Nuclear Navy. ... Nuclear marine propulsion is propulsion of a Merchant ship powered by a nuclear reactor. ... The Soviet Naval ensign The Soviet Naval jack The Soviet Navy (Russian: Военно-морской флот СССР, Voyenno-morskoy flot SSSR, literally Naval military forces of the USSR) was the naval arm of the Soviet armed forces. ... USS Scorpion (SSN-589) was the sixth ship of the United States Navy to be named for the scorpion, (hence the Scorpius constellation on its insignia). ... The second USS Thresher (SSN-593) was the lead ship of her class of nuclear-powered attack submarines in the United States Navy. ...

The future of the industry

Some experts predict that electricity shortages, fossil fuel price increases and concern over Greenhouse gas emissions will renew the demand for nuclear power plants. Watts Bar 1, which came on-line in 1997, was the last U.S. commercial nuclear reactor to go on-line. Increasing atmospheric CO2 levels as measured at Mauna Loa. ... The Watts Bar nuclear power plant is located between Chattanooga, Tennessee and Knoxville, Tennessee on a 1,770 acre (7 km²) site. ... 1997 (MCMXCVII) is a common year starting on Wednesday of the Gregorian calendar. ...

As of 2004, the immediate future of the industry in many countries still appeared uncertain, the most notable exceptions being Japan, China and India, all actively developing both fast and thermal technology, South Korea and the United States, developing thermal technology only, and South Africa and China, developing versions of the Pebble Bed Modular Reactor (PBMR). Finland and France actively pursue nuclear programs; Finland has a new AREVA plant under construction. Japan has an active nuclear construction program with new units brought on-line in 2005. In the U.S., three consortia responded in 2004 to the U.S. Department of Energy's solicitation under the Nuclear Power 2010 Program and were awarded matching funds - the Energy Policy Act of 2005 authorized subsidies for up to six new reactors, and authorized the Department of Energy to build a reactor to produce both electricity and hydrogen. As of the early 21st century, nuclear power is of particular interest to both China and India to serve their rapidly growing economies - both are developing fast breeder reactors. See also future energy development. 2004 (MMIV) was a leap year starting on Thursday of the Gregorian calendar. ... The pebble bed reactor is an advanced nuclear reactor design. ... The United States Department of Energy (DOE) is a Cabinet-level department of the United States government responsible for energy policy and nuclear safety. ... The Nuclear Power 2010 Program was unveiled by the Secretary of the Department of Energy on February 14, 2002 as one means towards addressing the expected need for new power plants. ... The Energy Policy Act of 2005 (Public Law 109-58) is a statute which was passed by the United States Congress on July 29, 2005 and signed into law on August 8, 2005 at Sandia National Laboratories in Albuquerque, New Mexico. ... The United States Department of Energy (DOE) is a Cabinet-level department of the United States government responsible for energy policy and nuclear safety. ... General Name, Symbol, Number hydrogen, H, 1 Chemical series nonmetals Group, Period, Block 1, 1, s Appearance colorless Atomic mass 1. ... In books based on the Demonic Era or Common Era, such as the Gregorian calendar, the 21st century is the current century, as of this writing. ... The fast breeder or fast breeder reactor (FBR) is a type of fast neutron reactor that produces more fissile material than it consumes. ... Energy development is the ongoing effort to provide abundant and accessible energy, through knowledge, skills and constructions. ...

On September 22, 2005 it was announced that two sites in the U.S. had been selected to receive new power reactors (exclusive of the new power reactor scheduled for INL) - see Nuclear Power 2010 Program. September 22 is the 265th day of the year in the Gregorian calendar (266th in leap years). ... 2005 (MMV) is a common year starting on Saturday of the Gregorian calendar. ... The Idaho National Laboratory (INL) is an 890 square mile (2,300 km²) complex located in the Idaho desert between the towns of Arco and Idaho Falls. ... The Nuclear Power 2010 Program was unveiled by the Secretary of the Department of Energy on February 14, 2002 as one means towards addressing the expected need for new power plants. ...

It is possible that the first new nuclear power plant to be built in the United States since the 1970s may be installed in the remote town of Galena, Alaska. The town's City Council approved the idea, and Toshiba proposed to install its model 4S "nuclear battery" in Galena free of charge as a test. Galena, Alaskas City Council on December 14, 2004 tentatively accepted a proposal from Toshiba Corporation to build a small nuclear reactor in the village as a demonstration. ... Toshiba Corporation (東芝, Tōshiba) (TYO: 6502) is a Japanese high technology electrical and electronics manufacturing firm, headquartered in Tokyo, Japan. ... The Toshiba 4S (Super Safe, Small and Simple) is a “nuclear battery” reactor design. ...

See also nuclear power phase-out, nuclear energy policy. A nuclear power plant at Grafenrheinfeld, Germany. ... Nuclear energy policy is a policy concerning all aspects of nuclear energy, such as mining, enrichment and storage of burned rods, electricity generation by nuclear reactors, and nuclear fuel reprocessing. ...

Method of operation

All commercial nuclear reactors produce heat through nuclear fission. In this process, the nucleus of an element such as uranium splits into two smaller atoms. This occurs naturally in radioactive elements, but it can be induced artificially by making some atoms absorb a neutron. This causes the nucleus to become unstable and makes it split apart very quickly. Sketch of induced nuclear fission, a neutron (n) strikes a uranium nucleus which splits into similar products (F. P.), and releases more neutrons to continue the process, and energy in the form of gamma and other radiation. ... Nucleus can mean: The Nuclear Envelope The nucleus is enveloped by a pair of membranes enclosing a lumen that is continuous with that of the endoplasmic reticulum. ... General Name, Symbol, Number uranium, U, 92 Chemical series actinides Group, Period, Block ?, 7, f Appearance silvery gray metallic Atomic mass 238. ... Properties In physics, the neutron is a subatomic particle with no net electric charge and a mass of 939. ...

The fission process for a uranium atom yields two smaller atoms, one to three fast-moving free neutrons, and energy. Uranium fission therefore releases more neutrons than it requires, and the reaction can become self sustaining if conditions are appropriate. This is called a chain reaction. A fast neutron is a free neutron with a kinetic energy level close to 1 MeV (10 TJ/kg, hence a speed of 14,000 km/s. ...

When a neutron is captured by a fissionable nucleus, it may cause fission immediately, or it may lead to an unstable species which undergoes fission a short time later. A mass of fissionable material is said to be a critical mass if each fission event leads to one or more fission events on average. A mass is said to be prompt critical if the immediate fission events are sufficient to carry on a chain reaction. A prompt critical mass will rapidly release an exponentially increasing amount of heat and cannot be controlled. Nuclear reactors are (with the exception of certain speculative subcritical reactors) designed to contain critical masses that are not prompt critical, so that control systems can react quickly enough to maintain a steady rate of heat production. San Francisco Critical Mass, 29th April, 2005. ... In nuclear engineering, an assembly is prompt critical if for each nuclear fission event, one or more of the immediate or prompt neutrons released causes an additional fission event. ... A subcritical reactor is a nuclear fission reactor that produces fission without achieving criticality. ...

The neutrons released by fission are moving quickly. Such "fast neutrons" are not easily absorbed by fissionable nuclei. Some reactors are designed to work with these neutrons, but most reactors use a neutron moderator to slow these neutrons down so that they are more easily absorbed. Such neutrons are often slowed until they are in thermal equilibrium with the reactor core; as a result, they are called thermal neutrons (or slow neutrons). A fast neutron is a free neutron with a kinetic energy level close to 1 MeV (10 TJ/kg, hence a speed of 14,000 km/s. ... In nuclear engineering, a neutron moderator is a medium which reduces the velocity of fast neutrons, thereby turning them into thermal neutrons capable of sustaining a nuclear chain reaction. ... In thermodynamics, a thermodynamic system is in thermodynamic equilibrium if its energy distribution equals a Maxwell-Boltzmann-distribution. ... A thermal neutron is a free neutron with a kinetic energy level of ca. ...

The amount of heat produced by a reactor is a crucial parameter. It may be controlled by adjusting the amount of neutron moderator in the reactor core, control rods consisting of neutron absorbers may be used to control the output, or the physical arrangement of the fuel may be changed. The Doppler broadening effect also serves to reduce the rate of fission as the temperature increases. Many reactors use several methods, both for control and for emergency shutdown. Doppler broadening is a broadening of spectral lines due to thermal agitation. ...

Reactor design

See also Nuclear power plant and nuclear reactor physics A nuclear power plant in Cattenom, France. ... 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 nuclear reactor is designed to carry out nuclear fission reactions on a large scale. This produces heat, fission products, and intense neutron radiation. In a nuclear power plant, that heat is used to do useful work. Some reactors, whether experimental or military, are designed with no concern for making use of the generated heat, as their goal is to make use of the neutron radiation to transmute elements. In either case, for all current nuclear reactors, it is essential that a nuclear chain reaction be continually sustained. Neutron radiation consists of free neutrons. ... A nuclear power plant in Cattenom, France. ... Transmutation is the conversion of one object into another. ... Albert Einsteins letter to President Roosevelt in 1939 about his concern, about (Nuclear chain reactions) Click for closeup of letter A nuclear chain reaction occurs when on average more than one nuclear reaction is caused by another nuclear reaction, thus leading to an exponential increase in the number of...

In a sustained nuclear chain reaction, the fission of a single fuel nucleus releases a few neutrons. These neutrons initially carry a great deal of energy (and are therefore called fast neutrons). These neutrons may be captured immediately by another fuel nucleus, or they may interact with a neutron moderator or a neutron absorber. The likelihood that a fast-moving neutron is captured by a fuel nucleus is relatively low, so it is often necessary to slow down the neutrons. This is done by allowing the neutrons to scatter off nuclei of a neutron moderator. After a few such scattering events, the neutron radiation has a thermal energy spectrum (that is, they are moving with the same average energy as a gas at the same temperature as the reactor core) and is much more easily captured by a fuel nucleus. A fast neutron is a free neutron with a kinetic energy level close to 1 MeV (10 TJ/kg, hence a speed of 14,000 km/s. ... In nuclear engineering, a neutron moderator is a medium which reduces the velocity of fast neutrons, thereby turning them into thermal neutrons capable of sustaining a nuclear chain reaction. ...

Paths of some neutrons in a thermal reactor

A nuclear reactor that uses a moderator is called a slow or thermal reactor, and it is normally categorized according to the type of moderator. Common moderators are heavy water and ordinary light water. Some reactors also use graphite, although it has a number of problems (see, for example, the Windscale fire and the Chernobyl accident). A reactor that is not moderated is called a fast reactor. The higher neutron flux allows some nuclear reactions to occur that are difficult to arrange in a slow reactor. In particular, it is possible to transmute thorium and other isotopes into usable fuel isotopes. Such a reactor can potentially produce more fuel than it consumes; for this reason fast reactors are sometimes called "breeder reactors". Download high resolution version (1000x714, 81 KB) Wikipedia does not have an article with this exact name. ... Download high resolution version (1000x714, 81 KB) Wikipedia does not have an article with this exact name. ... Heavy water is dideuterium oxide, or D2O or 2H2O. It is chemically the same as normal water, H2O, but the hydrogen atoms are of the heavy isotope deuterium, in which the nucleus contains a neutron in addition to the proton found in the nucleus of any hydrogen atom. ... In speaking of nuclear reactors, light water is ordinary water. ... Graphite (named by Abraham Gottlob Werner in 1789, from the Greek γραφειν: to draw/write, for its use in pencils) is one of the allotropes of carbon. ... On October 10, 1957, the graphite core of a British nuclear reactor at Windscale, Cumbria, caught fire releasing substantial amounts of radioactive contamination into the surrounding area. ... The nuclear power plant at Chernobyl prior to the completion of the sarcophagus. ... General Name, Symbol, Number thorium, Th, 90 Chemical series transition metals Group, Period, Block ?, 7, f Appearance silvery white Atomic mass 232. ...

A computer simulation of reactor core temperature. The white circles are fuel rods.

When a neutron is captured by a fuel nucleus, the nucleus may undergo fission immediately, it may remain in an unstable state for a short while before undergoing fission, or it may fail to undergo fission at all. Fission events that occur immediately are called "prompt" fission events, and if there are enough prompt events for the reaction to be self-sustaining without the delayed fission events, then the reactor is said to be prompt critical. In such a situation, the amount of fission in the reactor will grow exponentially and very quickly; the result would be a large explosion (although not one comparable to a nuclear weapon). Thus a stable nuclear reactor must be maintained in a critical but not prompt critical state. Controls are also essential to ensure that the temperature does not rise so high that the reactor is damaged or destroyed. Download high resolution version (2100x1678, 615 KB)Simulation of temperaturesinside a nuclear reactor. ... Download high resolution version (2100x1678, 615 KB)Simulation of temperaturesinside a nuclear reactor. ... In nuclear engineering, an assembly is prompt critical if for each nuclear fission event, one or more of the immediate or prompt neutrons released causes an additional fission event. ... The mushroom cloud of the atomic bombing of Nagasaki, Japan, 1945, rose some 18 km (11 mi) above the hypocenter. ...

A nuclear reactor is controlled by adjusting the configuration of neutron absorbers in and around the central core, the configuration of the neutron moderator (if any), and sometimes the configuration of the fuel itself. The most common arrangement is to include neutron-absorbing control rods which can be partially inserted into the reactor in order to damp its reaction. Such control rods normally require sophisticated monitoring equipment, so a number of advanced reactor designs (such as the pebble-bed reactor) have tried to build in passive safety systems which require no action by electronic, mechanical, or human agents to prevent plant overheating (see Passively safe). A control rod is a rod made of a chemical element capable of absorbing many neutrons without decaying themselves. ... The Pebble Bed Reactor is an advanced nuclear reactor design. ... Passively safe is a form of nuclear reactor which uses the laws of physics to keep the nuclear reaction under control rather than engineered safety systems. ...

In any nuclear reactor, some sort of cooling is necessary. In a nuclear power plant, the cooling system must be designed so that it can make use of the heat released. Most nuclear reactors use water as a coolant, either in a pressurized liquid form or by boiling into steam. Since water acts as a moderator, fast reactors cannot be cooled with water. Molten sodium or sodium salts are in current use. Reactors designed for transmutation only may simply release the heat to the environment. In physical chemistry and in engineering, steam refers to vaporized water. ... General Name, Symbol, Number sodium, Na, 11 Chemical series alkali metals Group, Period, Block 1, 3, s Appearance silvery white Atomic mass 22. ...

Safety

By regulation, as part of the design of any nuclear reactor provisions must be made for operator errors or failure of critical equipment. For this reason the "Defense in Depth" concept is employed to ensure operability of all systems when required for safety. All systems in nuclear plants have three main safety objectives:

• Control of Reactivity (ability to control the amount of neutron flux in the fuel either mechanically or chemically),
• Maintenance of Core Cooling (maintaining an adequate supply and backup supply of coolant to the core region) and
• Maintenance of Barriers to Release of Radiation (fuel cladding, primary barrier, containment and attenuation devices).

Where Systems, Structures and Components (SSC) are required to perform any duties supporting the three safety functions, they are provided with frequent inspection, operational or functional tests, and increased design, purchase and repair scrutiny as part of a Quality Assurance (QA) plan. Part of the design of these SSC includes redundancy (having multiple backup components), provision of independent systems (such as a requirement to have two or more separate systems performing the same function in parallel) "voting" on an interpretation of a signal, fail-safe design (knowing how a SSC will fail and what effect it will have on companion SSC) monitoring instrumentation and protection against "Common Mode Failure". Common Mode Failure prevents a single failure from affecting both "trains" or systems of independent, redundant equipment. Engineering performance is tested on a frequent basis (surveillance) to provide assurance (QA) of readiness to perform its designed function. It should be noted that many of these same design features are mandated on commercial airliners. In engineering and manufacturing, quality control or quality engineering is a set of measures taken to ensure that defective products or services are not produced, and that the design meets performance requirements. ...

On detection of process (pressure, temperature, radiation, flow, etc) indications outside of a normal range an alarm will sound and be "acknowledged" in the control room, where an operator makes adjustments. If the alarming parameters exceed set points further, the reactor, turbine or generator may provide a fault signal which automatically places the system in a safer (lower energy) mode and may terminate operations without operator control. In the case of a generator or turbine fault, steam will be limited or shut off and the turbine will slow. If the problem is not corrected quickly, a SCRAM will occur automatically inserting the control rods into the reactor core and slowing the neutron flux by over 99% in seconds. The plant can be restarted, but only after an investigation is completed. A SCRAM is an emergency shutdown of a nuclear reactor - though the term has been extended to cover shutdowns of other complex operations, such as server farms and even large model railroads (see Tech Model Railroad Club). ...

Each facility operates to a set of license conditions (Final Safety Analysis Report, or FSAR) specific to the units' design, location and environment. The license conditions, condensed in a set of Technical Specifications, describes the limits of power, certain process parameters, staff, training and qualifications, minimum available equipment and other physical and administrative requirements which must be in place in order to operate the reactor. Violation of the license conditions may result in fines and inability to operate the facility - also, since the license conditions constitute part of a federal license, plant personnel may face criminal charges.

Types of reactors

NC State's PULSTAR Reactor is a 1 MW pool-type research reactor with 4% enriched, pin-type fuel consisting of UO₂ pellets in zircaloy cladding.

The control room of NC State's Pulstar Nuclear Reactor.

A number of reactor technologies have been developed. Fission reactors can be divided roughly into two classes, depending on the energy of the neutrons that are used to sustain the fission chain reaction. Download high resolution version (480x640, 335 KB)Pulstar Nuclear Reactor. ... Download high resolution version (480x640, 335 KB)Pulstar Nuclear Reactor. ... North Carolina State University is an institution of higher learning located in Raleigh, North Carolina. ... Research reactors comprise a wide range of civil and commercial nuclear reactors which are generally not used for power generation. ... Zircaloy, also incorrectly called zircalloy, is a group of of high-zirconium alloys. ... Download high resolution version (439x601, 274 KB)Pulstar Nuclear Reactor. ... Download high resolution version (439x601, 274 KB)Pulstar Nuclear Reactor. ... North Carolina State University is an institution of higher learning located in Raleigh, North Carolina. ...

• Thermal (slow) reactors use slow or thermal neutrons. These are characterised by having moderating materials which are intended to slow the neutrons until they approach the average kinetic energy of the surrounding particles, that is, until they are thermalised. Thermal neutrons have a far higher probability of fissioning U-235, and a lower probability of capture by U-238 than the faster neutrons that result from fission do. As well as the moderator, thermal reactors have fuel (fissionable material), containments, pressure vessels, shielding, and instrumentation to monitor and control the reactor's systems. Most power reactors are of this type, and the first plutonium production reactors were thermal reactors using graphite as the moderator. Some thermal power reactors are more thermalised than others; Graphite (ex. Russian RBMK reactors) and heavy water moderated plants (ex. Canadian CANDU reactors) tend to be more thoroughly thermalised than PWRs and BWRs, which use light water (normal water) as the moderator (due to the extra thermalization, these types can use natural uranium/unenriched fuel).
• Fast reactors use fast neutrons to sustain the fission chain reaction, and are characterised by the lack of moderating material. They require highly enriched fuel (sometimes weapons-grade), or plutonium in order to reduce the amount of U-238 that would otherwise capture fast neutrons. Some are capable of producing more fuel than they consume, usually by converting U-238 to Pu-239. Some early power stations were fast reactors, as are some Russian naval propulsion units, and construction of prototypes is continuing, see fast breeder, but overall the class has not achieved the success of thermal reactors in any application. An example of this type of reactor is the Fast Breeder Reactor (FBR).

Thermal power reactors can again be divided into three types, depending on whether they use pressurised fuel channels, a large pressure vessel, or gas cooling. A thermal reactor is the most common category of nuclear reactor. ... A thermal neutron is a free neutron with a kinetic energy level of ca. ... In nuclear engineering, a neutron moderator is a medium which reduces the velocity of fast neutrons, thereby turning them into thermal neutrons capable of sustaining a nuclear chain reaction. ... Graphite (named by Abraham Gottlob Werner in 1789, from the Greek γραφειν: to draw/write, for its use in pencils) is one of the allotropes of carbon. ... RBMK is an acronym for the Russian reaktor bolshoi moshchnosty kanalny which means reactor (of) large power (with) channels, and describes a now-obsolete class of nuclear power reactor which was built only in the Soviet Union. ... The CANDU reactor is a pressurized-heavy water, natural-uranium power reactor designed in the 1960s by a partnership between Atomic Energy of Canada Limited and the Hydro-Electric Power Commission of Ontario as well as several private industry participants. ... A pressurized water reactor (PWR) is a type of nuclear power reactor that uses ordinary light water for both coolant and for neutron moderator. ... A boiling water reactor (BWR) is a light water reactor design used in some nuclear power stations. ... Natural uranium (NU) refers to refined uranium with the same isotopic ratios as found in nature. ... A fast neutron reactor or simply a fast reactor is a category of nuclear reactor in which the fission chain reaction is sustained by fast neutrons. ... General Name, Symbol, Number plutonium, Pu, 94 Chemical series actinides Group, Period, Block ?, 7, f Appearance silvery white Atomic mass (244) g/mol Electron configuration [Rn] 5f6 7s2 Electrons per shell 2, 8, 18, 32, 24, 8, 2 Physical properties Phase solid Density (near r. ... The fast breeder or fast breeder reactor (FBR) is a type of fast neutron reactor that produces more fissile material than it consumes. ... A pressure vessel is a structure designed to contain a fluid at a different pressure to the pressure surrounding the structure without changing volume. ...

• Pressure vessels holding steam heated by the reactor are used by most commercial and naval reactors. This serves as a layer of shielding and containment.

• Pressurised channels are used by the RBMK and CANDU reactors. Channel-type reactors can be refuelled under load, which has advantages and disadvantages discussed under CANDU reactor.

• Gas-cooled reactors are cooled by a circulating inert gas, usually helium, but nitrogen and carbon dioxide have also been used. Utilisation of the heat varies, depending on the reactor. Some reactors run hot enough that the gas can directly power a gas turbine. Older designs usually run the gas through a heat exchanger to make steam for a steam turbine. The pebble bed reactor uses a gas-cooled design.

Since water serves as a moderator, it cannot be used as a coolant in a fast reactor. Most designs for fast power reactors have been cooled by liquid metal, usually molten sodium. They have also been of two types, called pool and loop reactors. RBMK is an acronym for the Russian reaktor bolshoi moshchnosty kanalny which means reactor (of) large power (with) channels, and describes a now-obsolete class of nuclear power reactor which was built only in the Soviet Union. ... The CANDU reactor is a pressurized-heavy water, natural-uranium power reactor designed in the 1960s by a partnership between Atomic Energy of Canada Limited and the Hydro-Electric Power Commission of Ontario as well as several private industry participants. ... The CANDU reactor is a pressurized-heavy water, natural-uranium power reactor designed in the 1960s by a partnership between Atomic Energy of Canada Limited and the Hydro-Electric Power Commission of Ontario as well as several private industry participants. ... General Name, Symbol, Number helium, He, 2 Chemical series noble gases Group, Period, Block 18, 1, s Appearance colorless Atomic mass 4. ... General Name, Symbol, Number nitrogen, N, 7 Chemical series nonmetals Group, Period, Block 15, 2, p Appearance colorless Atomic mass 14. ... Carbon dioxide is an atmospheric gas composed of one carbon and two oxygen atoms. ... The pebble bed reactor is an advanced nuclear reactor design. ... General Name, Symbol, Number sodium, Na, 11 Chemical series alkali metals Group, Period, Block 1, 3, s Appearance silvery white Atomic mass 22. ...

Current families of reactors

• Pool type reactor
• Pressurized water reactor (PWR)
• Boiling water reactor (BWR)
• Fast breeder reactor (FBR)
• Pressurised Heavy Water Reactor (PHWR or CANDU)
• United States Naval reactor

Pool-type reactors are a type of nuclear reactor that has a core immersed in an open pool of water. ... A pressurized water reactor (PWR) is a type of nuclear power reactor that uses ordinary light water for both coolant and for neutron moderator. ... A boiling water reactor (BWR) is a light water reactor design used in some nuclear power stations. ... The fast breeder or fast breeder reactor (FBR) is a type of fast neutron reactor that produces more fissile material than it consumes. ... The CANDU reactor is a pressurized-heavy water, natural-uranium power reactor designed in the 1960s by a partnership between Atomic Energy of Canada Limited and the Hydro-Electric Power Commission of Ontario as well as several private industry participants. ... United States Naval reactors are given three-character designations consisting of a letter representing the ship type the reactor is designed for, a consecutive generation number, and a letter indicating the reactors designer. ...

Obsolescent types still in service

• Magnox reactor
• Advanced gas-cooled Reactor (AGR)
• Light water cooled graphite moderated reactor (RBMK)
• Fast neutron reactor

Magnox is an obsolesent type of nuclear power reactor; When operated on a short fuel cycle (which is uneconomic) they can also produce plutonium for nuclear weapons. ... An Advanced Gas Cooled Reactor (AGR) is a type of nuclear reactor. ... RBMK is an acronym for the Russian reaktor bolshoi moshchnosty kanalny which means reactor (of) large power (with) channels, and describes a now-obsolete class of nuclear power reactor which was built only in the Soviet Union. ... A fast neutron reactor or simply a fast reactor is a category of nuclear reactor in which the fission chain reaction is sustained by fast neutrons. ...

Other types of reactors

• Molten salt reactor
• Aqueous Homogeneous Reactor

A molten salt reactor is a type of nuclear reactor where the working fluid is a molten salt. ... Aqueous Homogenous Reactors are a type of nuclear reactor in which soluble nuclear salts (usually uranium sulfate or uranium nitrate) have been dissolved in water. ...

Advanced reactors

More than a dozen advanced reactor designs are in various stages of development. Some are evolutionary from the PWR, BWR and CANDU designs above, some are more radical departures. The former include the Advanced Boiling Water Reactor (ABWR), two of which are now operating with others are under construction. The best-known radical new design is the Pebble Bed Modular Reactor (PBMR), a High Temperature Gas Cooled Reactor (HTGCR). Other possible designs exist on the drawing board, notably the energy amplifier, awaiting political support and funding. Some, such as the Integral Fast Reactor (IFR), have been cancelled due to a political climate unfavorable to nuclear power. A pressurized water reactor (PWR) is a type of nuclear power reactor that uses ordinary (light) water for both coolant and for neutron moderator. ... A boiling water reactor (BWR) is a light water reactor design used in some nuclear power stations. ... The CANDU reactor is a pressurized-heavy water, natural-uranium power reactor designed in the 1960s by a partnership between Atomic Energy of Canada Limited and the Hydro-Electric Power Commission of Ontario as well as several private industry participants. ... The Advanced Boiling Water Reactor (ABWR) is an improved design of boiling water reactor. ... The pebble bed reactor is an advanced nuclear reactor design. ... In nuclear physics, an energy amplifier is a novel type of nuclear power reactor, a subcritical reactor, in which an energetic particle beam is used to stimulate a reaction, which in turn releases enough energy to power the particle accelerator and leave an energy profit for power generation. ... The Integral Fast Reactor or Advanced Liquid-Metal Reactor was a design for a nuclear reactor with a specialized nuclear fuel cycle. ...

Nuclear fuel cycle

Main article: nuclear fuel cycle The nuclear fuel cycle consists of front end steps that lead to the preparation of uranium for use as fuel for reactor operation and back end steps that are necessary to safely manage, prepare, and dispose of radioactive waste. ...

Thermal reactors generally depend on refined and enriched uranium. Some nuclear reactors can operate with a mixture of plutonium and uranium (see MOX). The process by which uranium ore is mined, processed, enriched, used, possibly reprocessed and disposed of is known as the nuclear fuel cycle. Enriched uranium is uranium whose uranium-235 content has been increased through the process of isotope separation. ... The Mox are a alien race that inhabit Planet X, they are divided into clans which seem to be forever at war. ... Nuclear reprocessing separates any usable elements (e. ... The nuclear fuel cycle consists of front end steps that lead to the preparation of uranium for use as fuel for reactor operation and back end steps that are necessary to safely manage, prepare, and dispose of radioactive waste. ...

Uranium is sampled and mined as other metals are, via open-pit mining or leach mining. Raw uranium ore found in the United States ranges from 0.05% to 0.3% uranium oxide. Uranium ore is not rare; the largest probable resources, extractable at a cost of US$80 per kilogram or cheaper, are located in Australia, Kazakhstan, Canada, South Africa, Brazil, Namibia, Russia, and the United States. The El Chino Mine located near Silver City, New Mexico is an open-pit copper mine Mining is the extraction of valuable minerals or other geological materials from the earth, usually (but not always) from an ore body, vein, or (coal) seam. ...

The raw ore is then milled, where it is ground and chemically leached. The resulting powder of natural uranium oxide is called "yellowcake". The yellowcake powder is then converted to uranium hexafluoride to prepare for enrichment. Powdered yellowcake in a drum Yellowcake (also known as urania and uranic oxide) is concentrated uranium oxide, obtained through the milling of uranium ore. ... Uranium hexafluoride, or UF6, is a compound used in the uranium enrichment process that produces fuel for nuclear reactors and nuclear weapons. ...

Since under 1% of the uranium found in nature is the easily fissionable U-235 isotope, the uranium must be enriched to about 4% U-235, usually by means of gaseous diffusion or gas centrifuge. The enriched result is then converted into uranium dioxide powder, which is pressed and fired onto pellet form. These pellets are stacked into tubes which are then sealed and called fuel rods. Many of these fuel rods are used in each nuclear reactor. Isotopes are forms of an element whose nuclei have the same atomic number–-the number of protons in the nucleus--but different atomic masses because they contain different numbers of neutrons. ... -1... The gas centrifuge is a hyper-centrifuge used to produce enriched uranium. ... Nuclear power station at Leibstadt, Switzerland. ...

Fueling of nuclear reactors

The amount of energy in the reservoir of nuclear fuel is frequently expressed in terms of "full-power days," which is the number of 24-hour periods (days) a reactor is scheduled for operation at full power output for the generation of heat energy. The number of full-power days in a reactor's operating cycle (between refueling outage times) is related to the amount of fissile uranium-235 (U-235) contained in the fuel assemblies at the beginning of the cycle. A higher percentage of U-235 in the core at the beginning of a cycle will permit the reactor to be run for a greater number of full-power days. Nuclear Fuel is used to generate Nuclear power. ... This article or section should include material from Fissile material In nuclear engineering, a fissile material is one that is capable of sustaining a chain reaction of nuclear fission. ... Uranium-235 is an isotope of uranium that differs from the elements other common isotope, uranium-238, by its ability to cause a rapidly expanding fission chain reaction. ...

At the end of the operating cycle, the fuel in some of the assemblies is "spent," and is discharged and replaced with new (fresh) fuel assemblies. Although in practice, it is the buildup of reacton poisons in nuclear fuel that determines the lifetime of nuclear fuel in a reactor; long before all possible fissions have taken place, the buildup of long-lived neutron absorbing fission products damps out the chain reaction. 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.

Not all reactors need to be shut down for refueling; for example, pebble bed reactors, molten salt reactors and CANDU reactors allow fuel to be shifted through the reactor while it is running. In a CANDU reactor, this also allows individual fuel elements to be moved about within the reactor core to places that are best suited to the amount of U-235 in the fuel element. The pebble bed reactor is an advanced nuclear reactor design. ... A molten salt reactor is a type of nuclear reactor where the working fluid is a molten salt. ... The CANDU reactor is a pressurized-heavy water, natural-uranium power reactor designed in the 1960s by a partnership between Atomic Energy of Canada Limited and the Hydro-Electric Power Commission of Ontario as well as several private industry participants. ...

The amount of energy extracted from nuclear fuel is called its "burn up," which is expressed in terms of the heat energy produced per initial unit of fuel weight. Burn up is commonly expressed as megawatt days thermal per metric ton of initial heavy metal.

Waste management

The final stage of the nuclear fuel cycle is the management of the still highly radioactive, "spent" fuel, which constitutes the most problematic component of the nuclear waste stream. After fifty years of nuclear power the question of how to deal with this material remains fraught with safety concerns and technical problems, and one of the most important lines of criticism of the industry is based on the long-term risks and costs associated with dealing with the waste. A Russian fissile material storage facility Radioactive waste is waste material containing radioactive chemical elements which does not have a practical purpose. ...

Management of the spent fuel can include various combinations of storage, reprocessing, and disposal. In practice storage has been the primary modality so far. Typically the spent fuel rods are stored in a pool of water which is usually located on-site. The water provides both cooling for the still-decaying uranium, and shielding from the continuing radioactivity.

Another, more permanent method of disposal of high-level nuclear waste calls for the material to be buried deep underground in certain geological formations. The Canadian government, for example, is seriously considering this method of disposal, known as the Deep Geological Disposal concept. Under the current plan, a vault is to be dug 500 to 1000 meters below ground, under the Canadian Shield, one of the most stable landforms on the planet. The vaults are to be dug inside geological formations known as batholiths, formed about a billion years ago. The used fuel bundles will be encased in a corrosion-resistant container, and further surrounded by a layer of buffer material, possibly of a special kind of clay (bentonite clay). The case itself is designed to last for thousands of years, while the clay would further slow the corrosion rates of the container. The batholiths themselves are chosen for their low ground-water movement rates, geological stability, and low economic value. (See The Canadian Nuclear FAQ, Waste Management section, by Dr. Jeremy Whitlock) Half Dome A batholith is a large emplacement of igneous intrusive (also called plutonic) rock that forms from cooled magma deep in the Earths crust. ... Bentonite - USGS Bentonite is an absorbent aluminium phyllosilicate generally impure clay consisting mostly of montmorillonite, (Na,Ca)0. ...

Reprocessing is attractive in principle because (1) it can recycle nuclear fuel and (2) it can prepare the waste material for disposal. Considerable experience with reprocessing in France however, has indicated that a one way fuel cycle based on extracting and processing fresh supplies of uranium and storing the spent fuel is more economical than reprocessing. Nuclear reprocessing separates any usable elements (e. ...

Natural nuclear reactors

A natural nuclear fission reactor can occur under certain circumstances that mimic the conditions in a constructed reactor. The only known natural nuclear reactor formed 2 billion years ago in Oklo, Gabon, Africa. [6] Such reactors can no longer form on Earth: radioactive decay over this immense time span has reduced the proportion of U-235 in naturally occurring uranium to below the amount required to sustain a chain reaction. Oklo is a place in the West African state of Gabon. ...

The natural nuclear reactors formed when a uranium-rich mineral deposit became inundated with groundwater that acted as a neutron moderator, and a strong chain reaction took place. The water moderator would boil away as the reaction increased, slowing it back down again and preventing a meltdown. The fission reaction was sustained for hundreds of thousands of years.

These natural reactors are extensively studied by scientists interested in geologic radioactive waste disposal. They offer a case study of how radioactive isotopes migrate through the earth's crust. This is a significant area of controversy as opponents of geologic waste disposal fear that isotopes from stored waste could end up in water supplies or be carried into the environment.

Related articles

• Nuclear Reactor Operator Badge
• United States Naval reactor
• List of nuclear reactors
• Green Field status

The Nuclear Reactor Operator Badge is a decoration of the United States Army which was issued between the years of 1965 and 1990. ... United States Naval reactors are given three-character designations consisting of a letter representing the ship type the reactor is designed for, a consecutive generation number, and a letter indicating the reactors designer. ... List of nuclear reactors is a comprehensive annotated list of all the nuclear reactors of the world, sorted by country. ... Green Field status is a term used to describe an end point wherein a parcel of land that had been in industrial use is, in principle, restored to the conditions existing before the construction of the plant. ...

See also

• Nuclear reactor physics
• Nuclear power
• Nuclear fission
• Nuclear fusion
• Nuclear power plant
• Nuclear meltdown
• Power plant
• Nuclear waste
• Electricity generation
• Nuclear physics
• Enrico Fermi
• Manhattan Project
• Nuclear marine propulsion
• Technology assessment
• List of nuclear accidents
• Energy amplifier
• Future energy development
• SCRAM
• SSTAR - LLNL design for a "world" reactor

Most nuclear reactors use a chain reaction to induce a controlled rate of nuclear fission in fissile material, releasing both energy and free neutrons. ... This article is about power derived from nuclear reactions. ... Sketch of induced nuclear fission, a neutron (n) strikes a uranium nucleus which splits into similar products (F. P.), and releases more neutrons to continue the process, and energy in the form of gamma and other radiation. ... The deuterium-tritium fusion reaction is considered the most promising for producing fusion power. ... A nuclear power plant in Cattenom, France. ... A nuclear meltdown occurs when the core of a nuclear reactor melts, and is generally considered a serious nuclear accident. ... A power station (also power plant) is a facility for the generation of electric power. ... A Russian fissile material storage facility Radioactive waste is waste material containing radioactive chemical elements which does not have a practical purpose. ... Itaipu Dam is a hydroelectric generating station Electricity generation is the first process in the delivery of electricity to consumers. ... Nuclear physics is the branch of physics concerned with the nucleus of the atom. ... Enrico Fermi in the 1940s. ... Control panels and operators for calutrons at the Y-12 Plant in Oak Ridge, Tennessee. ... Nuclear marine propulsion is propulsion of a Merchant ship powered by a nuclear reactor. ... Technology assessment (TA, German Technikfolgenabschätzung) is the study and evaluation of new technologies. ... Pathways from airborne radioactive contamination to man This article covers notable accidents involving nuclear material. ... In nuclear physics, an energy amplifier is a novel type of nuclear power reactor, a subcritical reactor, in which an energetic particle beam is used to stimulate a reaction, which in turn releases enough energy to power the particle accelerator and leave an energy profit for power generation. ... Energy development is the ongoing effort to provide abundant and accessible energy, through knowledge, skills and constructions. ... A SCRAM is an emergency shutdown of a nuclear reactor - though the term has been extended to cover shutdowns of other complex operations, such as server farms and even large model railroads (see Tech Model Railroad Club). ... SSTAR is an acronym for the small, sealed, transportable, autonomous reactor - being primarily researched and developed in the US by Lawrence Livermore National Laboratory. ... Aerial view of the lab and surrounding area. ...

References and links

• Worldwide maps of nuclear power stations
• Uranium.Info publishing uranium price since 1968.
• Energy Information Administration provides lots of statistics and information on the industry.
• World Nuclear Fuel Facilities
• The Uranium Information Centre provided some of the original material in this article.
• The US Nuclear Regulatory Commission supervises the US Nuclear industry
• The Idaho National Engineering and Environmental Laboratory developed nuclear reactor technology in the United States - INEL Newsdesk - Experimental Breeder Reactor-I opens for summer tours
• The International Atomic Energy Agency (IAEA) works with its Member States and multiple partners worldwide to promote safe, secure and peaceful nuclear technologies.
  • IAEA Website
  • IAEA's Power Reactor Information System (PRIS)
  • IAEA's Knowledge Base on Gas Cooled Reactors
  • IAEA's Web directory of nuclear related resources on the Internet
• The Pebble Bed Modular Reactor - Whyfiles.org - On a bed of pebbles
• World Nuclear Association - A pro nuclear site
• Greenpeace Nuclear Campaign - An anti-nuclear site
• A Debate: Is Nuclear Power The Solution to Global Warming?
• Environmentalists for Nuclear Power, pro nuclear site
• SCK.CEN Belgian Nuclear Research Centre - pro nuclear site
• The Nuclear Energy Option by Bernard Cohen. Pro nuclear book which compares risks of nuclear power with other methods of energy generation.
• Union of Concerned Scientists, Concerns re: US nuclear reactor program
• The Canadian Nuclear FAQ - a very information-rich resource about Canadian CANDU reactors.
• The Nuclear Boy Scout - Eagle and Eagle TV production about David Hahn's nuclear reactor experiment[[zh: