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[[File:Uranium enrichment proportions.svg|thumb|Proportions of uranium-238 (blue) and uranium-235 (red) found naturally versus enriched grades]]
'''Enriched uranium''' is a type of [[uranium]] in which the percent composition of [[uranium-235]] (written <sup>235</sup>U) has been increased through the process of [[isotope separation]]. Naturally occurring uranium is composed of three major isotopes: [[uranium-238]] (<sup>238</sup>U with 99.2739–99.2752% [[natural abundance]]), [[uranium-235]] (<sup>235</sup>U, 0.7198–0.7202%), and [[uranium-234]] (<sup>234</sup>U, 0.0050–0.0059%).<ref>{{cite web | title = Uranium Isotopes | url = http://www.globalsecurity.org/wmd/intro/u-isotopes.htm |publisher=GlobalSecurity.org | accessdate = 2020-02-05}}</ref> <sup>235</sup>U is the only [[primordial nuclide|nuclide existing in nature]] (in any appreciable amount) that is [[fissile]] with [[thermal neutron]]s.<ref>{{cite book|author=OECD Nuclear Energy Agency|title=Nuclear Energy Today|publisher=OECD Publishing|year=2003|isbn=9789264103283|page=25|url=https://books.google.com/books?id=PvL7twdmK9sC&pg=PA25}}</ref>
Enriched uranium is a critical component for both civil [[Nuclear power|nuclear power generation]] and military [[nuclear weapon]]s. The [[International Atomic Energy Agency]] attempts to monitor and control enriched uranium supplies and processes in its efforts to ensure nuclear power generation safety and curb [[nuclear proliferation|nuclear weapons proliferation]].
There are about 2,000 [[tonne]]s (t, Mg) of highly enriched uranium in the world,<ref>{{cite web | url=http://docs.nrdc.org/nuclear/files/nuc_06129701a_185.pdf | title=Safeguarding Nuclear Weapon-Usable Materials in Russia | author=Thomas B. Cochran ([[Natural Resources Defense Council]]) | publisher=Proceedings of international forum on illegal nuclear traffic | date=12 June 1997 | url-status=dead | archiveurl=https://web.archive.org/web/20120722184311/http://docs.nrdc.org/nuclear/files/nuc_06129701a_185.pdf | archivedate=22 July 2012 | df=dmy-all }}</ref> produced mostly for [[nuclear power]], nuclear weapons, [[Nuclear marine propulsion|naval propulsion]], and smaller quantities for [[research reactor]]s.
The <sup>238</sup>U remaining after enrichment is known as [[depleted uranium]] (DU), and is considerably less [[radioactive]] than even natural uranium, though still very dense and extremely hazardous in granulated form – such granules are a natural by-product of the shearing action that makes it useful for [[Vehicle armor|armor]]-[[Staballoy|penetrating weapons]] and [[radiation shielding]].
{{toclimit|3}}
==Grades==
Uranium as it is taken directly from the Earth is not suitable as fuel for most nuclear reactors and requires additional processes to make it usable. Uranium is mined either underground or in an open pit depending on the depth at which it is found. After the [[uranium ore]] is mined, it must go through a milling process to extract the uranium from the ore.
This is accomplished by a combination of chemical processes with the end product being concentrated uranium oxide, which is known as "[[yellowcake]]", contains roughly 60% uranium whereas the ore typically contains less than 1% uranium and as little as 0.1% uranium.
After the milling process is complete, the uranium must next undergo a process of conversion, "to either [[uranium dioxide]], which can be used as the fuel for those types of reactors that do not require enriched uranium, or into [[uranium hexafluoride]], which can be enriched to produce fuel for the majority of types of reactors".<ref>{{cite web|url=https://www.hsdl.org/?view&did=770258 |title=Radiological Sources of Potential Exposure and/or Contamination |publisher=U.S. Army Center for Health Promotion and Preventive Medicine |page=27 |date=June 1999 |access-date=1 July 2019}}</ref> Naturally-occurring uranium is made of a mixture of <sup>235</sup>U and <sup>238</sup>U. The <sup>235</sup>U is [[fissile]], meaning it is easily split with [[Neutron|neutrons]] while the remainder is <sup>238</sup>U, but in nature, more than 99% of the extracted ore is <sup>238</sup>U. Most nuclear reactors require enriched uranium, which is uranium with higher concentrations of <sup>235</sup>U ranging between 3.5% and 4.5%. There are two commercial enrichment processes: [[gaseous diffusion]] and [[gas centrifugation]]. Both enrichment processes involve the use of uranium hexafluoride and produce enriched uranium oxide.
[[File:LEUPowder.jpg|thumb|A drum of [[yellowcake]] (a mixture of uranium precipitates)]]
===Reprocessed uranium (RepU)===
{{Main|Reprocessed uranium}}
''Reprocessed uranium'' (RepU) is a product of [[nuclear fuel cycle]]s involving [[nuclear reprocessing]] of [[spent fuel]]. RepU recovered from [[light water reactor]] (LWR) spent fuel typically contains slightly more <sup>235</sup>U than [[natural uranium]], and therefore could be used to fuel reactors that customarily use natural uranium as fuel, such as [[CANDU reactor]]s. It also contains the undesirable isotope [[uranium-236]], which undergoes [[neutron capture]], wasting neutrons (and requiring higher <sup>235</sup>U enrichment) and creating [[neptunium-237]], which would be one of the more mobile and troublesome radionuclides in [[deep geological repository]] disposal of nuclear waste.
===Low enriched uranium (LEU)===
''Low enriched uranium'' (LEU) has a lower than 20% concentration of <sup>235</sup>U; for instance, in commercial LWR, the most prevalent power reactors in the world, uranium is enriched to 3 to 5% <sup>235</sup>U. High-assay LEU is enriched from 5–20%.<ref>{{Cite web|url=https://www.energy.gov/sites/prod/files/2019/04/f61/HALEU%20Report%20to%20NEAC%20Committee%203-28-19%20%28FINAL%29.pdf|title=High-assay low enriched uranium|last=Herczeg|first=John W.|date=March 28, 2019|website=energy.gov|url-status=live|archive-url=|archive-date=|access-date=}}</ref> Fresh LEU used in [[research reactor]]s is usually enriched 12% to 19.75% <sup>235</sup>U, the latter concentration is used to replace HEU fuels when converting to LEU.<ref>{{cite journal |url=http://www.princeton.edu/~aglaser/2005aglaser_why20percent.pdf |title=About the Enrichment Limit for Research Reactor Conversion : Why 20%? |author=Alexander Glaser |publisher=Princeton University |date=6 November 2005 |accessdate=18 April 2014}}</ref>
===Highly enriched uranium (HEU)===
[[File:HEUraniumC.jpg|thumb|A [[billet (bar stock)|billet]] of highly enriched uranium metal]]
''Highly enriched uranium'' (HEU) has a 20% or higher concentration of <sup>235</sup>U. The fissile uranium in [[nuclear weapon]] primaries usually contains 85% or more of <sup>235</sup>U known as [[weapons-grade]], though theoretically for an [[nuclear weapon design|implosion design]], a minimum of 20% could be sufficient (called weapon-usable) although it would require hundreds of kilograms of material and "would not be practical to design";<ref name="DefWpnsUsable">{{cite web |url= http://web.ornl.gov/info/reports/1998/3445606060721.pdf |title= Definition of Weapons-Usable Uranium-233 |last1= Forsberg |first1= C. W. |last2= Hopper |first2= C. M. |last3= Richter |first3= J. L. |last4= Vantine |first4= H. C. |date= March 1998 |work= ORNL/TM-13517 |publisher= Oak Ridge National Laboratories |accessdate= 30 October 2013 |url-status= dead |archiveurl= https://web.archive.org/web/20131102011417/http://web.ornl.gov/info/reports/1998/3445606060721.pdf |archivedate= 2 November 2013 |df= dmy-all }}</ref><ref name="NWFAQ">{{cite web |url= http://www.nuclearweaponarchive.org/Nwfaq/Nfaq4-1.html#Nfaq4.1.7.1 |title= Nuclear Weapons FAQ, Section 4.1.7.1: Nuclear Design Principles – Highly Enriched Uranium |last1= Sublette |first1= Carey |date= 4 October 1996 |work= Nuclear Weapons FAQ |accessdate=2 October 2010}}</ref> even lower enrichment is hypothetically possible, but as the enrichment percentage decreases the [[Critical mass (nuclear)|critical mass]] for unmoderated [[fast neutron]]s rapidly increases, with for example, an [[infinity|infinite]] mass of 5.4% <sup>235</sup>U being required.<ref name="DefWpnsUsable"/> For [[Criticality (status)|criticality]] experiments, enrichment of uranium to over 97% has been accomplished.<ref>{{cite journal |last=Mosteller |first=R.D. |year=1994 |title=Detailed Reanalysis of a Benchmark Critical Experiment: Water-Reflected Enriched-Uranium Sphere |journal=Los Alamos Technical Paper |issue=LA–UR–93–4097 |page=2 |url=http://www.osti.gov/bridge/servlets/purl/10120434-rruwqp/native/10120434.PDF |accessdate=19 December 2007 |quote=The enrichment of the pin and of one of the hemispheres was 97.67 w/o, while the enrichment of the other hemisphere was 97.68 w/o.|doi=10.2172/10120434 }}</ref>
The very first uranium bomb, [[Little Boy]], dropped by the [[United States]] on [[Hiroshima]] in 1945, used 64 kilograms of 80% enriched uranium. Wrapping the weapon's fissile core in a [[neutron reflector]] (which is standard on all nuclear explosives) can dramatically reduce the critical mass. Because the core was surrounded by a good neutron reflector, at explosion it comprised almost 2.5 critical masses. Neutron reflectors, compressing the fissile core via implosion, [[fusion boosting]], and "tamping", which slows the expansion of the fissioning core with inertia, allow [[nuclear weapon design]]s that use less than what would be one bare-sphere critical mass at normal density. The presence of too much of the <sup>238</sup>U isotope inhibits the runaway [[nuclear chain reaction]] that is responsible for the weapon's power. The critical mass for 85% highly enriched uranium is about {{convert|50|kg}}, which at normal density would be a sphere about {{convert|17|cm}} in diameter.
Later US nuclear weapons usually use [[plutonium-239]] in the primary stage, but the jacket or tamper secondary stage, which is compressed by the primary nuclear explosion often uses HEU with enrichment between 40% and 80%<ref>{{cite web|url=http://nuclearweaponarchive.org/Nwfaq/Nfaq6.html#nfaq6.2 |title=Nuclear Weapons FAQ |accessdate=26 January 2013}}</ref>
along with the [[nuclear fusion|fusion]] fuel [[lithium deuteride]]. For the secondary of a large nuclear weapon, the higher critical mass of less-enriched uranium can be an advantage as it allows the core at explosion time to contain a larger amount of fuel. The <sup>238</sup>U is not said to be fissile but still is fissionable by fast neutrons (>2 MeV) such as the ones produced during D-T fusion.
HEU is also used in [[fast neutron reactor]]s, whose cores require about 20% or more of fissile material, as well as in [[Nuclear marine propulsion|naval reactors]], where it often contains at least 50% <sup>235</sup>U, but typically does not exceed 90%. The [[Fermi 1|Fermi-1]] commercial fast reactor prototype used HEU with 26.5% <sup>235</sup>U. Significant quantities of HEU are used in the production of [[medical isotopes]], for example [[molybdenum-99]] for [[technetium-99m generator]]s.<ref>{{cite journal |title=Feasibility of Eliminating the Use of Highly Enriched Uranium in the Production of Medical Radioisotopes |author1=Frank N. Von Hippel |author2=Laura H. Kahn |journal=Science & Global Security |volume=14 |issue= 2 & 3|date=December 2006 |pages=151–162 |doi=10.1080/08929880600993071 |bibcode=2006S&GS...14..151V }}</ref>
==Enrichment methods==
[[Isotope separation]] is difficult because two isotopes of the same element have nearly identical chemical properties, and can only be separated gradually using small mass differences. (<sup>235</sup>U is only 1.26% lighter than <sup>238</sup>U.) This problem is compounded by the fact that uranium is rarely separated in its atomic form, but instead as a compound (<sup>235</sup>UF<sub>6</sub> is only 0.852% lighter than <sup>238</sup>UF<sub>6</sub>.)
A [[cascade (chemical engineering)|cascade]] of identical stages produces successively higher concentrations of <sup>235</sup>U. Each stage passes a slightly more concentrated product to the next stage and returns a slightly less concentrated residue to the previous stage.
There are currently two generic commercial methods employed internationally for enrichment: [[gaseous diffusion]] (referred to as ''first'' generation) and [[gas centrifuge]] (''second'' generation), which consumes only 2% to 2.5%<ref>{{cite web|url=http://www.world-nuclear.org/info/Nuclear-Fuel-Cycle/Conversion-Enrichment-and-Fabrication/Uranium-Enrichment/#.UWrver-IRAs|title=Uranium Enrichment|work=world-nuclear.org}}</ref> as much energy as gaseous diffusion (at least a "factor of 20" more efficient).<ref>{{citation|url=https://fas.org/sgp/othergov/doe/lanl/pubs/00416663.pdf |quote=The throughput per centrifuge unit is very small compared to that of a diffusion unit so small, in fact, that it is not compensated by the higher enrichment per unit. To produce the same amount of reactor-grade fuel requires a considerably larger number (approximately 50,000 to 500,000] of centrifuge units than diffusion units. This disadvantage, however, is outweighed by '''the considerably lower (by a factor of 20) energy consumption per SWU''' for the gas centrifuge|title=Economic Perspective for Uranium Enrichment}}</ref> Some work is being done that would use [[Nuclear magnetic resonance|nuclear resonance]]; however there is no reliable evidence that any nuclear resonance processes have been scaled up to production.
===Diffusion techniques===
====Gaseous diffusion====
[[File:Gaseous Diffusion (44021367082) (cropped).jpg|thumb|Gaseous diffusion uses semi-permeable membranes to separate enriched uranium]]
{{Main|Gaseous diffusion}}
Gaseous diffusion is a technology used to produce enriched uranium by forcing gaseous [[uranium hexafluoride]] (''hex'') through [[semi-permeable membrane]]s. This produces a slight separation between the molecules containing <sup>235</sup>U and <sup>238</sup>U. Throughout the [[Cold War]], gaseous diffusion played a major role as a uranium enrichment technique, and as of 2008 accounted for about 33% of enriched uranium production,<ref name="Lodge">{{cite web|url=http://www.asx.com.au/asxpdf/20080410/pdf/318j6y3ctrzwqf.pdf | title=Lodge Partners Mid-Cap Conference 11 April 2008 | publisher=Silex Ltd | date = 11 April 2008}}</ref> but in 2011 was deemed an obsolete technology that is steadily being replaced by the later generations of technology as the diffusion plants reach their ends-of-life.<ref>{{cite web |author=Rod Adams |url=http://atomicinsights.com/2011/05/mcconnell-asks-doe-to-keep-using-60-year-old-enrichment-plant-to-save-jobs.html |title=McConnell asks DOE to keep using 60 year old enrichment plant to save jobs |publisher=Atomic Insights |date=24 May 2011 |accessdate=26 January 2013 |url-status=dead |archiveurl=http://archive.wikiwix.com/cache/20130128020737/http://atomicinsights.com/2011/05/mcconnell-asks-doe-to-keep-using-60-year-old-enrichment-plant-to-save-jobs.html |archivedate=28 January 2013 |df=dmy-all }}</ref> In 2013, the [[Paducah Gaseous Diffusion Plant|Paducah]] facility in the US ceased operating, it was the last commercial <sup>235</sup>U gaseous diffusion plant in the world.<ref>{{cite web |url=http://www.world-nuclear-news.org/ENF_Paducah_enrichment_plant_to_be_closed_2805132.html |title=Paducah enrichment plant to be closed. ''The 1950s facility is the last remaining gaseous diffusion uranium enrichment plant in the world.''}}</ref>
====Thermal diffusion====
Thermal diffusion uses the transfer of heat across a thin liquid or gas to accomplish isotope separation. The process exploits the fact that the lighter <sup>235</sup>U gas molecules will diffuse toward a hot surface, and the heavier <sup>238</sup>U gas molecules will diffuse toward a cold surface. The [[S-50 (Manhattan Project)|S-50]] plant at [[Oak Ridge, Tennessee]] was used during [[World War II]] to prepare feed material for the [[#Electromagnetic isotope separation|EMIS]] process. It was abandoned in favor of gaseous diffusion.
===Centrifuge techniques===
====Gas centrifuge====
{{Main|Gas centrifuge}}
[[File:Gas centrifuge cascade.jpg|thumb|A cascade of gas centrifuges at a U.S. enrichment plant]]
The gas centrifuge process uses a large number of rotating cylinders in series and parallel formations. Each cylinder's rotation creates a strong [[centripetal force]] so that the heavier gas molecules containing <sup>238</sup>U move tangentially toward the outside of the cylinder and the lighter gas molecules rich in <sup>235</sup>U collect closer to the center. It requires much less energy to achieve the same separation than the older gaseous diffusion process, which it has largely replaced and so is the current method of choice and is termed ''second generation''. It has a separation factor per stage of 1.3 relative to gaseous diffusion of 1.005,<ref name="Lodge" /> which translates to about one-fiftieth of the energy requirements. Gas centrifuge techniques produce close to 100% of the world's enriched uranium.
====Zippe centrifuge====
[[File:Zippe-type gas centrifuge.svg|left|thumb|upright|Diagram of the principles of a Zippe-type gas centrifuge with U-238 represented in dark blue and U-235 represented in light blue]]
The [[Zippe centrifuge]] is an improvement on the standard gas centrifuge, the primary difference being the use of heat. The bottom of the rotating cylinder is heated, producing convection currents that move the <sup>235</sup>U up the cylinder, where it can be collected by scoops. This improved centrifuge design is used commercially by [[Urenco Group|Urenco]] to produce nuclear fuel and was used by [[Pakistan]] in their nuclear weapons program.
===Laser techniques===
Laser processes promise lower energy inputs, lower capital costs and lower tails assays, hence significant economic advantages. Several laser processes have been investigated or are under development. ''Separation of isotopes by laser excitation'' ([[SILEX]]) is well advanced and licensed for commercial operation in 2012.
====Atomic vapor laser isotope separation (AVLIS)====
''[[AVLIS|Atomic vapor laser isotope separation]]'' employs specially tuned lasers<ref>[[F. J. Duarte]] and L.W. Hillman (Eds.), ''Dye Laser Principles'' (Academic, New York, 1990) Chapter 9.</ref> to separate isotopes of uranium using selective ionization of [[hyperfine transitions]]. The technique uses [[laser]]s tuned to frequencies that ionize <sup>235</sup>U atoms and no others. The positively charged <sup>235</sup>U ions are then attracted to a negatively charged plate and collected.
====Molecular laser isotope separation (MLIS)====
''[[Molecular laser isotope separation]]'' uses an infrared laser directed at [[Uranium hexafluoride|UF<sub>6</sub>]], exciting molecules that contain a <sup>235</sup>U atom. A second laser frees a [[fluorine]] atom, leaving [[uranium pentafluoride]], which then precipitates out of the gas.
====Separation of isotopes by laser excitation (SILEX)====
''[[SILEX|Separation of isotopes by laser excitation]]'' is an Australian development that also uses [[Uranium hexafluoride |UF<sub>6</sub>]]. After a protracted development process involving U.S. enrichment company [[USEC]] acquiring and then relinquishing commercialization rights to the technology, [[GE Hitachi Nuclear Energy]] (GEH) signed a commercialization agreement with [[Silex Systems]] in 2006.<ref>{{cite press release|url =http://www.ge-energy.com/about/press/en/2006_press/052206b.htm |archiveurl=https://web.archive.org/web/20060614092643/http://www.ge-energy.com/about/press/en/2006_press/052206b.htm|archivedate=14 June 2006|title = GE Signs Agreement With Silex Systems Of Australia To Develop Uranium Enrichment Technology|date =22 May 2006|publisher = GE Energy }}</ref> GEH has since built a demonstration test loop and announced plans to build an initial commercial facility.<ref>{{cite web |title= GE Hitachi Nuclear Energy Selects Wilmington, N.C. as Site for Potential Commercial Uranium Enrichment Facility |url=http://www.businesswire.com/portal/site/ge/index.jsp?ndmViewId=news_view&ndmConfigId=1004554&newsId=20080430006101&newsLang=en&vnsId=681|publisher=Business Wire|accessdate=30 September 2012|date=30 April 2008}}</ref> Details of the process are classified and restricted by intergovernmental agreements between United States, Australia, and the commercial entities. SILEX has been projected to be an order of magnitude more efficient than existing production techniques but again, the exact figure is classified.<ref name="Lodge" /> In August, 2011 Global Laser Enrichment, a subsidiary of GEH, applied to the U.S. [[Nuclear Regulatory Commission]] (NRC) for a permit to build a commercial plant.<ref>{{cite news |last=Broad |first=William J. |title=Laser Advances in Nuclear Fuel Stir Terror Fear |url=https://www.nytimes.com/2011/08/21/science/earth/21laser.html |accessdate=21 August 2011 |newspaper= [[The New York Times]] |date=20 August 2011}}</ref> In September 2012, the NRC issued a license for GEH to build and operate a commercial SILEX enrichment plant, although the company had not yet decided whether the project would be profitable enough to begin construction, and despite concerns that the technology could contribute to [[nuclear proliferation]].<ref>{{cite news|url=https://www.nytimes.com/2012/09/28/business/energy-environment/uranium-plant-using-laser-technology-wins-us-approval.html?ref=science |work=New York Times |title=Uranium Plant Using Laser Technology Wins U.S. Approval |date=September 2012}}</ref>
===Other techniques===
====Aerodynamic processes====
[[File:Aerodynamic enrichment nozzle.svg|thumb|Schematic diagram of an aerodynamic nozzle. Many thousands of these small foils would be combined in an enrichment unit.]]
[[File:LIGA-Doppelumlenksystem.jpg|right|thumb| The X-ray based [[LIGA]] manufacturing process was originally developed at the Forschungszentrum Karlsruhe, Germany, to produce nozzles for isotope enrichment.<ref name=Becker-1982>{{Cite journal | author=Becker, E. W. | last2=Ehrfeld | first2=W. | last3=Münchmeyer | first3=D. | last4=Betz | first4=H. | last5=Heuberger | first5=A. | last6=Pongratz | first6=S. | last7=Glashauser | first7=W. | last8=Michel | first8=H. J. | last9=Siemens | first9=R. | title=Production of Separation-Nozzle Systems for Uranium Enrichment by a Combination of X-Ray Lithography and Galvanoplastics | journal=Naturwissenschaften | volume=69 | pages=520–523 | year=1982 | doi=10.1007/BF00463495 | issue=11 | bibcode=1982NW.....69..520B }}</ref>]]
Aerodynamic enrichment processes include the Becker jet nozzle techniques developed by E. W. Becker and associates using the [[LIGA]] process and the [[vortex tube]] separation process. These [[aerodynamic]] separation processes depend upon diffusion driven by pressure gradients, as does the gas centrifuge. They in general have the disadvantage of requiring complex systems of cascading of individual separating elements to minimize energy consumption. In effect, aerodynamic processes can be considered as non-rotating centrifuges. Enhancement of the centrifugal forces is achieved by dilution of [[Uranium hexafluoride|UF<sub>6</sub>]] with [[hydrogen]] or [[helium]] as a carrier gas achieving a much higher flow velocity for the gas than could be obtained using pure uranium hexafluoride. The [[NECSA|Uranium Enrichment Corporation of South Africa]] (UCOR) developed and deployed the continuous Helikon vortex separation cascade for high production rate low enrichment and the substantially different semi-batch Pelsakon low production rate high enrichment cascade both using a particular vortex tube separator design, and both embodied in industrial plant.<ref name="The Pelsakon Cascade for Uranium Enrichment">{{cite journal|last=Smith|first=Michael|author2=Jackson A G M|title=Dr|journal=South African Institution of Chemical Engineers – Conference 2000|year=2000|pages=280–289}}</ref> A demonstration plant was built in [[Brazil]] by NUCLEI, a consortium led by [[Industrias Nucleares do Brasil]] that used the separation nozzle process. However all methods have high energy consumption and substantial requirements for removal of waste heat; none are currently still in use.
====Electromagnetic isotope separation====
{{Main|Calutron}}
[[File:Electromagnetic separation.svg|thumb|Schematic diagram of uranium isotope separation in a [[calutron]] shows how a strong magnetic field is used to redirect a stream of uranium ions to a target, resulting in a higher concentration of uranium-235 (represented here in dark blue) in the inner fringes of the stream.]]
In the [[electromagnetic isotope separation]] process (EMIS), metallic uranium is first vaporized, and then ionized to positively charged ions. The cations are then accelerated and subsequently deflected by magnetic fields onto their respective collection targets. A production-scale [[mass spectrometer]] named the [[Calutron]] was developed during World War II that provided some of the <sup>235</sup>U used for the [[Little Boy]] nuclear bomb, which was dropped over [[Hiroshima]] in 1945. Properly the term 'Calutron' applies to a multistage device arranged in a large oval around a powerful electromagnet. Electromagnetic isotope separation has been largely abandoned in favour of more effective methods.
====Chemical methods====
One chemical process has been demonstrated to pilot plant stage but not used for production. The French CHEMEX process exploited a very slight difference in the two isotopes' propensity to change [[Valence (chemistry)|valency]] in [[redox|oxidation/reduction]], using immiscible aqueous and organic phases. An ion-exchange process was developed by the [[Asahi Chemical Company]] in [[Japan]] that applies similar chemistry but effects separation on a proprietary resin [[ion-exchange]] column.
====Plasma separation====
Plasma separation process (PSP) describes a technique that makes use of [[superconducting magnet]]s and [[plasma physics]]. In this process, the principle of [[ion cyclotron resonance]] is used to selectively energize the <sup>235</sup>U isotope in a [[Plasma (physics)|plasma]] containing a mix of [[ion]]s. The French developed their own version of PSP, which they called RCI. Funding for RCI was drastically reduced in 1986, and the program was suspended around 1990, although RCI is still used for stable isotope separation.
==Separative work unit==
{{further|Separative work units}}"Separative work" – the amount of separation done by an enrichment process – is a function of the concentrations of the feedstock, the enriched output, and the depleted tailings; and is expressed in units that are so calculated as to be proportional to the total input (energy / machine operation time) and to the mass processed. Separative work is ''not'' energy. The same amount of separative work will require different amounts of energy depending on the efficiency of the separation technology. Separative work is measured in ''Separative work units'' SWU, kg SW, or kg UTA (from the German ''Urantrennarbeit'' – literally ''uranium separation work'')
* 1 SWU = 1 kg SW = 1 kg UTA
* 1 kSWU = 1 tSW = 1 t UTA
* 1 MSWU = 1 ktSW = 1 kt UTA
==Cost issues==
In addition to the separative work units provided by an enrichment facility, the other important parameter to be considered is the mass of natural uranium (NU) that is needed to yield a desired mass of enriched uranium. As with the number of SWUs, the amount of feed material required will also depend on the level of enrichment desired and upon the amount of <sup>235</sup>U that ends up in the depleted uranium. However, unlike the number of SWUs required during enrichment, which increases with decreasing levels of <sup>235</sup>U in the depleted stream, the amount of NU needed will decrease with decreasing levels of <sup>235</sup>U that end up in the DU.
For example, in the enrichment of LEU for use in a light water reactor it is typical for the enriched stream to contain 3.6% <sup>235</sup>U (as compared to 0.7% in NU) while the depleted stream contains 0.2% to 0.3% <sup>235</sup>U. In order to produce one kilogram of this LEU it would require approximately 8 kilograms of NU and 4.5 SWU if the DU stream was allowed to have 0.3% <sup>235</sup>U. On the other hand, if the depleted stream had only 0.2% <sup>235</sup>U, then it would require just 6.7 kilograms of NU, but nearly 5.7 SWU of enrichment. Because the amount of NU required and the number of SWUs required during enrichment change in opposite directions, if NU is cheap and enrichment services are more expensive, then the operators will typically choose to allow more <sup>235</sup>U to be left in the DU stream whereas if NU is more expensive and enrichment is less so, then they would choose the opposite.
==Downblending==<!-- This section is linked from [[Radioactive waste]] -->
The opposite of enriching is downblending; surplus HEU can be downblended to LEU to make it suitable for use in commercial nuclear fuel.
The HEU feedstock can contain unwanted uranium isotopes: [[Uranium-234|<sup>234</sup>U]] is a minor isotope contained in natural uranium; during the enrichment process, its concentration increases but remains well below 1%. High concentrations of [[Uranium-236|<sup>236</sup>U]] are a byproduct from irradiation in a reactor and may be contained in the HEU, depending on its manufacturing history. HEU reprocessed from nuclear weapons material production reactors (with an <sup>235</sup>U assay of approx. 50%) may contain <sup>236</sup>U concentrations as high as 25%, resulting in concentrations of approximately 1.5% in the blended LEU product. [[Uranium-236|<sup>236</sup>U]] is a [[neutron poison]]; therefore the actual <sup>235</sup>U concentration in the LEU product must be raised accordingly to compensate for the presence of <sup>236</sup>U.
The blendstock can be NU, or DU, however depending on feedstock quality, SEU at typically 1.5 wt% <sup>235</sup>U may used as a blendstock to dilute the unwanted byproducts that may be contained in the HEU feed. Concentrations of these isotopes in the LEU product in some cases could exceed [[ASTM]] specifications for nuclear fuel, if NU, or DU were used. So, the HEU downblending generally cannot contribute to the waste management problem posed by the existing large stockpiles of depleted uranium. At present, 95 percent of the world's stocks of depleted uranium remain in secure storage.{{citation needed|date=January 2020}}
A major downblending undertaking called the [[Megatons to Megawatts Program]] converts ex-Soviet weapons-grade HEU to fuel for U.S. commercial power reactors. From 1995 through mid-2005, 250 tonnes of high-enriched uranium (enough for 10,000 warheads) was recycled into low-enriched-uranium. The goal is to recycle 500 tonnes by 2013. The decommissioning programme of Russian nuclear warheads accounted for about 13% of total world requirement for enriched uranium leading up to 2008.<ref name="Lodge" />
The [[United States Enrichment Corporation]] has been involved in the disposition of a portion of the 174.3 tonnes of highly enriched uranium (HEU) that the U.S. government declared as surplus military material in 1996. Through the U.S. HEU Downblending Program, this HEU material, taken primarily from dismantled U.S. nuclear warheads, was recycled into low-enriched uranium (LEU) fuel, used by [[nuclear power plants]] to generate electricity.<ref>{{cite web|url = http://www.usec.com/v2001_02/HTML/Megatons_DOEstatus.asp|date = 1 May 2000 |title = Status Report: USEC-DOE Megatons to Megawatts Program|archiveurl=https://web.archive.org/web/20010406102039/http://www.usec.com/v2001_02/HTML/Megatons_DOEstatus.asp |archivedate=6 April 2001|publisher = USEC.com }}</ref><ref>{{cite web|title =Megatons to Megawatts|website = centrusenergy.com|date = December 2013|url= https://www.centrusenergy.com/who-we-are/history/megatons-to-megawatts/}}</ref>
==Global enrichment facilities==
The following countries are known to operate enrichment facilities: Argentina, Brazil, China, France, Germany, India, Iran, Japan, the Netherlands, North Korea, Pakistan, Russia, the United Kingdom, and the United States.<ref name=IEER-2004>{{Cite book|url=http://www.ieer.org/reports/uranium/enrichment.pdf|title=Uranium enrichment|author1=Arjun Makhijani |author2=Lois Chalmers |author3=Brice Smith |date=15 October 2004|publisher=Institute for Energy and Environmental Research|accessdate=21 November 2009}}</ref><ref>{{cite report |page=730 |url=http://www.aph.gov.au/binaries/house/committee/isr/uranium/report/fullreport.pdf |title=Australia's uranium - Greenhouse friendly fuel for an energy hungry world |work=Standing Committee on Industry and Resources |publisher=The Parliament of the Commonwealth of Australia |date=November 2006 |accessdate=3 April 2015}}</ref> Belgium, Iran, Italy, and Spain hold an investment interest in the French [[Eurodif]] enrichment plant, with [[Dominique Lorentz#Eurodif and Iran's nuclear program|Iran's holding]] entitling it to 10% of the enriched uranium output. Countries that had enrichment programs in the past include Libya and South Africa, although Libya's facility was never operational.<ref>{{cite news|url=http://news.bbc.co.uk/1/hi/world/middle_east/5278806.stm | title=Q&A: Uranium enrichment | author=BBC | date = 1 September 2006 | accessdate=3 January 2010 | work=BBC News}}</ref> Australia has developed a [[Atomic vapor laser isotope separation|laser enrichment]] process known as SILEX, which it intends to pursue through financial investment in a U.S. commercial venture by General Electric.<ref>{{cite news|url=http://www.smh.com.au/news/national/laser-enrichment-could-cut-cost-of-nuclear-power/2006/05/26/1148524888448.html|title=Laser enrichment could cut cost of nuclear power|newspaper=The Sydney Morning Herald|date=26 May 2006}}</ref> It has also been claimed that Israel has a uranium enrichment program housed at the [[Negev Nuclear Research Center]] site near [[Dimona]].<ref name=nwa-19971210>{{cite web|url=http://nuclearweaponarchive.org/Israel/|date=10 December 1997|title=Israel's Nuclear Weapons Program|publisher=Nuclear Weapon Archive|accessdate=7 October 2007}}</ref>
==Codename==
During the [[Manhattan Project]] weapons-grade highly enriched uranium was given the codename '''oralloy''',{{citation needed|date=January 2020}} a shortened version of [[Oak Ridge, Tennessee|Oak Ridge]] [[alloy]],{{citation needed|date=January 2020}} after the location of the plants where the uranium was enriched. The term oralloy is still occasionally used to refer to enriched uranium.
==See also==
* [[List of laser articles]]
* [[MOX fuel]]
* [[Nuclear fuel bank]]
* [[Orano]]
* [[Uranium market]]
* [[Uranium mining]]
==References==
{{reflist}}
==External links==
{{Wiktionary}}
* [https://web.archive.org/web/20090531024234/http://alsos.wlu.edu/qsearch.aspx?browse=science%2FEnriching+Uranium Annotated bibliography on enriched uranium from the Alsos Digital Library for Nuclear Issues]
* [http://www.silex.com.au Silex Systems Ltd]
* [http://world-nuclear.org/info/inf28.html Uranium Enrichment], World Nuclear Association
* [https://fas.org/sgp/othergov/doe/heu/index.html Overview and history of U.S. HEU production]
* [https://web.archive.org/web/20070303234531/http://www.huliq.com/tags/uranium-enrichment News Resource on Uranium Enrichment]
* [http://www.chemcases.com/nuclear/nc-07.htm Nuclear Chemistry-Uranium Enrichment]
* [https://web.archive.org/web/20110613105504/http://www.neimagazine.com/story.asp?storyCode=2050947 A busy year for SWU (a 2008 review of the commercial enrichment marketplace)], Nuclear Engineering International, 1 September 2008
* [https://web.archive.org/web/20110727073116/http://books.sipri.org/product_info?c_product_id=286 ''Uranium Enrichment and Nuclear Weapon Proliferation'', by Allan S. Krass, Peter Boskma, Boelie Elzen and Wim A. Smit, 296 pp., published for SIPRI by Taylor and Francis Ltd, London, 1983]
* {{cite web|last=Poliakoff|first=Martyn|title=How do you enrich Uranium?|url=http://www.periodicvideos.com/videos/feature_uranium_enrichment.htm|work=[[The Periodic Table of Videos]]|publisher=[[University of Nottingham]]|authorlink=Martyn Poliakoff|year=2009}}
* {{cite web|last1=Gilinsky|first=V.|last2=Hoehn|first2=W.|title=The Military Significance of Small Uranium Enrichment Facilities Fed with Low-Enrichment Uranium (Redacted)|url=http://oai.dtic.mil/oai/oai?verb=getRecord&metadataPrefix=html&identifier=ADA613260|publisher=[[RAND Corporation]]|date=December 1969|website=[[Defense Technical Information Center]]|access-date=12 February 2016|archive-url=https://web.archive.org/web/20160216062519/http://oai.dtic.mil/oai/oai?verb=getRecord&metadataPrefix=html&identifier=ADA613260|archive-date=16 February 2016|url-status=dead}}
{{Nuclear Technology}}
{{DEFAULTSORT:Enriched Uranium}}
[[Category:Isotope separation]]
[[Category:Nuclear fuels]]
[[Category:Nuclear materials|Uranium, Enriched]]
[[Category:Nuclear weapon design]]
[[Category:Uranium]]' |
New page wikitext, after the edit (new_wikitext ) | '{{Use dmy dates|date=August 2013}}
[[File:Uranium enrichment proportions.svg|thumb|Proportions of uranium-238 (blue) and uranium-235 (red) found naturally versus enriched grades]]
'''Enriched uranium''' is a type of [[uranium]] in which the percent composition of [[uranium-235]] (written <sup>235</sup>U) has been increased through the process of [[isotope separation]]. Naturally occurring uranium is composed of three major isotopes: [[uranium-238]] (<sup>238</sup>U with 99.2739–99.2752% [[natural abundance]]), [[uranium-235]] (<sup>235</sup>U, 0.7198–0.7202%), and [[uranium-234]] (<sup>234</sup>U, 0.0050–0.0059%).<ref>{{cite web | title = Uranium Isotopes | url = http://www.globalsecurity.org/wmd/intro/u-isotopes.htm |publisher=GlobalSecurity.org | accessdate = 2020-02-05}}</ref> <sup>235</sup>U is the only [[primordial nuclide|nuclide existing in nature]] (in any appreciable amount) that is [[fissile]] with [[thermal neutron]]s.<ref>{{cite book|author=OECD Nuclear Energy Agency|title=Nuclear Energy Today|publisher=OECD Publishing|year=2003|isbn=9789264103283|page=25|url=https://books.google.com/books?id=PvL7twdmK9sC&pg=PA25}}</ref>
Enriched uranium is a critical component for both civil [[Nuclear power|nuclear power generation]] and military [[nuclear weapon]]s. The [[International Atomic Energy Agency]] attempts to monitor and control enriched uranium supplies and processes in its efforts to ensure nuclear power generation safety and curb [[nuclear proliferation|nuclear weapons proliferation]].
There are about 2,000 [[tonne]]s (t, Mg) of highly enriched uranium in the world,<ref>{{cite web | url=http://docs.nrdc.org/nuclear/files/nuc_06129701a_185.pdf | title=Safeguarding Nuclear Weapon-Usable Materials in Russia | author=Thomas B. Cochran ([[Natural Resources Defense Council]]) | publisher=Proceedings of international forum on illegal nuclear traffic | date=12 June 1997 | url-status=dead | archiveurl=https://web.archive.org/web/20120722184311/http://docs.nrdc.org/nuclear/files/nuc_06129701a_185.pdf | archivedate=22 July 2012 | df=dmy-all }}</ref> produced mostly for [[nuclear power]], nuclear weapons, [[Nuclear marine propulsion|naval propulsion]], and smaller quantities for [[research reactor]]s.
The <sup>238</sup>U remaining after enrichment is known as [[depleted uranium]] (DU), and is considerably less [[radioactive]] than even natural uranium, though still very dense and extremely hazardous in granulated form – such granules are a natural by-product of the shearing action that makes it useful for [[Vehicle armor|armor]]-[[Staballoy|penetrating weapons]] and [[radiation shielding]].
{{toclimit|3}}
==Grades==
Uranium as it is taken directly from the Earth is not suitable as fuel for most nuclear reactors and requires additional processes to make it usable. Uranium is mined either underground or in an open pit depending on the depth at which it is found. After the [[uranium ore]] is mined, it must go through a milling process to extract the uranium from the ore.be used to fuel reactors that customarily use natural uranium as fuel, such as [[CANDU reactor]]s. It also contains the undesirable isotope [[uranium-236]], which undergoes [[neutron capture]], wasting neutrons (and requiring higher <sup>235</sup>U enrichment) and creating [[neptunium-237]], which would be one of the more mobile and troublesome radionuclides in [[deep geological repository]] disposal of nuclear waste.
==Enrichment methods==
[[Isotope separation]] is difficult because two isotopes of the same element have nearly identical chemical properties, and can only be separated gradually using small mass differences. (<sup>235</sup>U is only 1.26% lighter than <sup>238</sup>U.) This problem is compounded by the fact that uranium is rarely separated in its atomic form, but instead as a compound (<sup>235</sup>UF<sub>6</sub> is only 0.852% lighter than <sup>238</sup>UF<sub>6</sub>.)
A [[cascade (chemical engineering)|cascade]] of identical stages produces successively higher concentrations of <sup>235</sup>U. Each stage passes a slightly more concentrated product to the next stage and returns a slightly less concentrated residue to the previous stage.
There are currently two generic commercial methods employed internationally for enrichment: [[gaseous diffusion]] (referred to as ''first'' generation) and [[gas centrifuge]] (''second'' generation), which consumes only 2% to 2.5%<ref>{{cite web|url=http://www.world-nuclear.org/info/Nuclear-Fuel-Cycle/Conversion-Enrichment-and-Fabrication/Uranium-Enrichment/#.UWrver-IRAs|title=Uranium Enrichment|work=world-nuclear.org}}</ref> as much energy as gaseous diffusion (at least a "factor of 20" more efficient).<ref>{{citation|url=https://fas.org/sgp/othergov/doe/lanl/pubs/00416663.pdf |quote=The throughput per centrifuge unit is very small compared to that of a diffusion unit so small, in fact, that it is not compensated by the higher enrichment per unit. To produce the same amount of reactor-grade fuel requires a considerably larger number (approximately 50,000 to 500,000] of centrifuge units than diffusion units. This disadvantage, however, is outweighed by '''the considerably lower (by a factor of 20) energy consumption per SWU''' for the gas centrifuge|title=Economic Perspective for Uranium Enrichment}}</ref> Some work is being done that would use [[Nuclear magnetic resonance|nuclear resonance]]; however there is no reliable evidence that any nuclear resonance processes have been scaled up to production.
===Diffusion techniques===
====Gaseous diffusion====
[[File:Gaseous Diffusion (44021367082) (cropped).jpg|thumb|Gaseous diffusion uses semi-permeable membranes to separate enriched uranium]]
{{Main|Gaseous diffusion}}
Gaseous diffusion is a technology used to produce enriched uranium by forcing gaseous [[uranium hexafluoride]] (''hex'') through [[semi-permeable membrane]]s. This produces a slight separation between the molecules containing <sup>235</sup>U and <sup>238</sup>U. Throughout the [[Cold War]], gaseous diffusion played a major role as a uranium enrichment technique, and as of 2008 accounted for about 33% of enriched uranium production,<ref name="Lodge">{{cite web|url=http://www.asx.com.au/asxpdf/20080410/pdf/318j6y3ctrzwqf.pdf | title=Lodge Partners Mid-Cap Conference 11 April 2008 | publisher=Silex Ltd | date = 11 April 2008}}</ref> but in 2011 was deemed an obsolete technology that is steadily being replaced by the later generations of technology as the diffusion plants reach their ends-of-life.<ref>{{cite web |author=Rod Adams |url=http://atomicinsights.com/2011/05/mcconnell-asks-doe-to-keep-using-60-year-old-enrichment-plant-to-save-jobs.html |title=McConnell asks DOE to keep using 60 year old enrichment plant to save jobs |publisher=Atomic Insights |date=24 May 2011 |accessdate=26 January 2013 |url-status=dead |archiveurl=http://archive.wikiwix.com/cache/20130128020737/http://atomicinsights.com/2011/05/mcconnell-asks-doe-to-keep-using-60-year-old-enrichment-plant-to-save-jobs.html |archivedate=28 January 2013 |df=dmy-all }}</ref> In 2013, the [[Paducah Gaseous Diffusion Plant|Paducah]] facility in the US ceased operating, it was the last commercial <sup>235</sup>U gaseous diffusion plant in the world.<ref>{{cite web |url=http://www.world-nuclear-news.org/ENF_Paducah_enrichment_plant_to_be_closed_2805132.html |title=Paducah enrichment plant to be closed. ''The 1950s facility is the last remaining gaseous diffusion uranium enrichment plant in the world.''}}</ref>
====Thermal diffusion====
Thermal diffusion uses the transfer of heat across a thin liquid or gas to accomplish isotope separation. The process exploits the fact that the lighter <sup>235</sup>U gas molecules will diffuse toward a hot surface, and the heavier <sup>238</sup>U gas molecules will diffuse toward a cold surface. The [[S-50 (Manhattan Project)|S-50]] plant at [[Oak Ridge, Tennessee]] was used during [[World War II]] to prepare feed material for the [[#Electromagnetic isotope separation|EMIS]] process. It was abandoned in favor of gaseous diffusion.
===Centrifuge techniques===
====Gas centrifuge====
{{Main|Gas centrifuge}}
[[File:Gas centrifuge cascade.jpg|thumb|A cascade of gas centrifuges at a U.S. enrichment plant]]
The gas centrifuge process uses a large number of rotating cylinders in series and parallel formations. Each cylinder's rotation creates a strong [[centripetal force]] so that the heavier gas molecules containing <sup>238</sup>U move tangentially toward the outside of the cylinder and the lighter gas molecules rich in <sup>235</sup>U collect closer to the center. It requires much less energy to achieve the same separation than the older gaseous diffusion process, which it has largely replaced and so is the current method of choice and is termed ''second generation''. It has a separation factor per stage of 1.3 relative to gaseous diffusion of 1.005,<ref name="Lodge" /> which translates to about one-fiftieth of the energy requirements. Gas centrifuge techniques produce close to 100% of the world's enriched uranium.
====Zippe centrifuge====
[[File:Zippe-type gas centrifuge.svg|left|thumb|upright|Diagram of the principles of a Zippe-type gas centrifuge with U-238 represented in dark blue and U-235 represented in light blue]]
The [[Zippe centrifuge]] is an improvement on the standard gas centrifuge, the primary difference being the use of heat. The bottom of the rotating cylinder is heated, producing convection currents that move the <sup>235</sup>U up the cylinder, where it can be collected by scoops. This improved centrifuge design is used commercially by [[Urenco Group|Urenco]] to produce nuclear fuel and was used by [[Pakistan]] in their nuclear weapons program.
===Laser techniques===
Laser processes promise lower energy inputs, lower capital costs and lower tails assays, hence significant economic advantages. Several laser processes have been investigated or are under development. ''Separation of isotopes by laser excitation'' ([[SILEX]]) is well advanced and licensed for commercial operation in 2012.
====Atomic vapor laser isotope separation (AVLIS)====
''[[AVLIS|Atomic vapor laser isotope separation]]'' employs specially tuned lasers<ref>[[F. J. Duarte]] and L.W. Hillman (Eds.), ''Dye Laser Principles'' (Academic, New York, 1990) Chapter 9.</ref> to separate isotopes of uranium using selective ionization of [[hyperfine transitions]]. The technique uses [[laser]]s tuned to frequencies that ionize <sup>235</sup>U atoms and no others. The positively charged <sup>235</sup>U ions are then attracted to a negatively charged plate and collected.
====Molecular laser isotope separation (MLIS)====
''[[Molecular laser isotope separation]]'' uses an infrared laser directed at [[Uranium hexafluoride|UF<sub>6</sub>]], exciting molecules that contain a <sup>235</sup>U atom. A second laser frees a [[fluorine]] atom, leaving [[uranium pentafluoride]], which then precipitates out of the gas.
====Separation of isotopes by laser excitation (SILEX)====
''[[SILEX|Separation of isotopes by laser excitation]]'' is an Australian development that also uses [[Uranium hexafluoride |UF<sub>6</sub>]]. After a protracted development process involving U.S. enrichment company [[USEC]] acquiring and then relinquishing commercialization rights to the technology, [[GE Hitachi Nuclear Energy]] (GEH) signed a commercialization agreement with [[Silex Systems]] in 2006.<ref>{{cite press release|url =http://www.ge-energy.com/about/press/en/2006_press/052206b.htm |archiveurl=https://web.archive.org/web/20060614092643/http://www.ge-energy.com/about/press/en/2006_press/052206b.htm|archivedate=14 June 2006|title = GE Signs Agreement With Silex Systems Of Australia To Develop Uranium Enrichment Technology|date =22 May 2006|publisher = GE Energy }}</ref> GEH has since built a demonstration test loop and announced plans to build an initial commercial facility.<ref>{{cite web |title= GE Hitachi Nuclear Energy Selects Wilmington, N.C. as Site for Potential Commercial Uranium Enrichment Facility |url=http://www.businesswire.com/portal/site/ge/index.jsp?ndmViewId=news_view&ndmConfigId=1004554&newsId=20080430006101&newsLang=en&vnsId=681|publisher=Business Wire|accessdate=30 September 2012|date=30 April 2008}}</ref> Details of the process are classified and restricted by intergovernmental agreements between United States, Australia, and the commercial entities. SILEX has been projected to be an order of magnitude more efficient than existing production techniques but again, the exact figure is classified.<ref name="Lodge" /> In August, 2011 Global Laser Enrichment, a subsidiary of GEH, applied to the U.S. [[Nuclear Regulatory Commission]] (NRC) for a permit to build a commercial plant.<ref>{{cite news |last=Broad |first=William J. |title=Laser Advances in Nuclear Fuel Stir Terror Fear |url=https://www.nytimes.com/2011/08/21/science/earth/21laser.html |accessdate=21 August 2011 |newspaper= [[The New York Times]] |date=20 August 2011}}</ref> In September 2012, the NRC issued a license for GEH to build and operate a commercial SILEX enrichment plant, although the company had not yet decided whether the project would be profitable enough to begin construction, and despite concerns that the technology could contribute to [[nuclear proliferation]].<ref>{{cite news|url=https://www.nytimes.com/2012/09/28/business/energy-environment/uranium-plant-using-laser-technology-wins-us-approval.html?ref=science |work=New York Times |title=Uranium Plant Using Laser Technology Wins U.S. Approval |date=September 2012}}</ref>
===Other techniques===
====Aerodynamic processes====
[[File:Aerodynamic enrichment nozzle.svg|thumb|Schematic diagram of an aerodynamic nozzle. Many thousands of these small foils would be combined in an enrichment unit.]]
[[File:LIGA-Doppelumlenksystem.jpg|right|thumb| The X-ray based [[LIGA]] manufacturing process was originally developed at the Forschungszentrum Karlsruhe, Germany, to produce nozzles for isotope enrichment.<ref name=Becker-1982>{{Cite journal | author=Becker, E. W. | last2=Ehrfeld | first2=W. | last3=Münchmeyer | first3=D. | last4=Betz | first4=H. | last5=Heuberger | first5=A. | last6=Pongratz | first6=S. | last7=Glashauser | first7=W. | last8=Michel | first8=H. J. | last9=Siemens | first9=R. | title=Production of Separation-Nozzle Systems for Uranium Enrichment by a Combination of X-Ray Lithography and Galvanoplastics | journal=Naturwissenschaften | volume=69 | pages=520–523 | year=1982 | doi=10.1007/BF00463495 | issue=11 | bibcode=1982NW.....69..520B }}</ref>]]
Aerodynamic enrichment processes include the Becker jet nozzle techniques developed by E. W. Becker and associates using the [[LIGA]] process and the [[vortex tube]] separation process. These [[aerodynamic]] separation processes depend upon diffusion driven by pressure gradients, as does the gas centrifuge. They in general have the disadvantage of requiring complex systems of cascading of individual separating elements to minimize energy consumption. In effect, aerodynamic processes can be considered as non-rotating centrifuges. Enhancement of the centrifugal forces is achieved by dilution of [[Uranium hexafluoride|UF<sub>6</sub>]] with [[hydrogen]] or [[helium]] as a carrier gas achieving a much higher flow velocity for the gas than could be obtained using pure uranium hexafluoride. The [[NECSA|Uranium Enrichment Corporation of South Africa]] (UCOR) developed and deployed the continuous Helikon vortex separation cascade for high production rate low enrichment and the substantially different semi-batch Pelsakon low production rate high enrichment cascade both using a particular vortex tube separator design, and both embodied in industrial plant.<ref name="The Pelsakon Cascade for Uranium Enrichment">{{cite journal|last=Smith|first=Michael|author2=Jackson A G M|title=Dr|journal=South African Institution of Chemical Engineers – Conference 2000|year=2000|pages=280–289}}</ref> A demonstration plant was built in [[Brazil]] by NUCLEI, a consortium led by [[Industrias Nucleares do Brasil]] that used the separation nozzle process. However all methods have high energy consumption and substantial requirements for removal of waste heat; none are currently still in use.
====Electromagnetic isotope separation====
{{Main|Calutron}}
[[File:Electromagnetic separation.svg|thumb|Schematic diagram of uranium isotope separation in a [[calutron]] shows how a strong magnetic field is used to redirect a stream of uranium ions to a target, resulting in a higher concentration of uranium-235 (represented here in dark blue) in the inner fringes of the stream.]]
In the [[electromagnetic isotope separation]] process (EMIS), metallic uranium is first vaporized, and then ionized to positively charged ions. The cations are then accelerated and subsequently deflected by magnetic fields onto their respective collection targets. A production-scale [[mass spectrometer]] named the [[Calutron]] was developed during World War II that provided some of the <sup>235</sup>U used for the [[Little Boy]] nuclear bomb, which was dropped over [[Hiroshima]] in 1945. Properly the term 'Calutron' applies to a multistage device arranged in a large oval around a powerful electromagnet. Electromagnetic isotope separation has been largely abandoned in favour of more effective methods.
====Chemical methods====
One chemical process has been demonstrated to pilot plant stage but not used for production. The French CHEMEX process exploited a very slight difference in the two isotopes' propensity to change [[Valence (chemistry)|valency]] in [[redox|oxidation/reduction]], using immiscible aqueous and organic phases. An ion-exchange process was developed by the [[Asahi Chemical Company]] in [[Japan]] that applies similar chemistry but effects separation on a proprietary resin [[ion-exchange]] column.
====Plasma separation====
Plasma separation process (PSP) describes a technique that makes use of [[superconducting magnet]]s and [[plasma physics]]. In this process, the principle of [[ion cyclotron resonance]] is used to selectively energize the <sup>235</sup>U isotope in a [[Plasma (physics)|plasma]] containing a mix of [[ion]]s. The French developed their own version of PSP, which they called RCI. Funding for RCI was drastically reduced in 1986, and the program was suspended around 1990, although RCI is still used for stable isotope separation.
==Separative work unit==
{{further|Separative work units}}"Separative work" – the amount of separation done by an enrichment process – is a function of the concentrations of the feedstock, the enriched output, and the depleted tailings; and is expressed in units that are so calculated as to be proportional to the total input (energy / machine operation time) and to the mass processed. Separative work is ''not'' energy. The same amount of separative work will require different amounts of energy depending on the efficiency of the separation technology. Separative work is measured in ''Separative work units'' SWU, kg SW, or kg UTA (from the German ''Urantrennarbeit'' – literally ''uranium separation work'')
* 1 SWU = 1 kg SW = 1 kg UTA
* 1 kSWU = 1 tSW = 1 t UTA
* 1 MSWU = 1 ktSW = 1 kt UTA
==Cost issues==
In addition to the separative work units provided by an enrichment facility, the other important parameter to be considered is the mass of natural uranium (NU) that is needed to yield a desired mass of enriched uranium. As with the number of SWUs, the amount of feed material required will also depend on the level of enrichment desired and upon the amount of <sup>235</sup>U that ends up in the depleted uranium. However, unlike the number of SWUs required during enrichment, which increases with decreasing levels of <sup>235</sup>U in the depleted stream, the amount of NU needed will decrease with decreasing levels of <sup>235</sup>U that end up in the DU.
For example, in the enrichment of LEU for use in a light water reactor it is typical for the enriched stream to contain 3.6% <sup>235</sup>U (as compared to 0.7% in NU) while the depleted stream contains 0.2% to 0.3% <sup>235</sup>U. In order to produce one kilogram of this LEU it would require approximately 8 kilograms of NU and 4.5 SWU if the DU stream was allowed to have 0.3% <sup>235</sup>U. On the other hand, if the depleted stream had only 0.2% <sup>235</sup>U, then it would require just 6.7 kilograms of NU, but nearly 5.7 SWU of enrichment. Because the amount of NU required and the number of SWUs required during enrichment change in opposite directions, if NU is cheap and enrichment services are more expensive, then the operators will typically choose to allow more <sup>235</sup>U to be left in the DU stream whereas if NU is more expensive and enrichment is less so, then they would choose the opposite.
==Downblending==<!-- This section is linked from [[Radioactive waste]] -->
The opposite of enriching is downblending; surplus HEU can be downblended to LEU to make it suitable for use in commercial nuclear fuel.
The HEU feedstock can contain unwanted uranium isotopes: [[Uranium-234|<sup>234</sup>U]] is a minor isotope contained in natural uranium; during the enrichment process, its concentration increases but remains well below 1%. High concentrations of [[Uranium-236|<sup>236</sup>U]] are a byproduct from irradiation in a reactor and may be contained in the HEU, depending on its manufacturing history. HEU reprocessed from nuclear weapons material production reactors (with an <sup>235</sup>U assay of approx. 50%) may contain <sup>236</sup>U concentrations as high as 25%, resulting in concentrations of approximately 1.5% in the blended LEU product. [[Uranium-236|<sup>236</sup>U]] is a [[neutron poison]]; therefore the actual <sup>235</sup>U concentration in the LEU product must be raised accordingly to compensate for the presence of <sup>236</sup>U.
The blendstock can be NU, or DU, however depending on feedstock quality, SEU at typically 1.5 wt% <sup>235</sup>U may used as a blendstock to dilute the unwanted byproducts that may be contained in the HEU feed. Concentrations of these isotopes in the LEU product in some cases could exceed [[ASTM]] specifications for nuclear fuel, if NU, or DU were used. So, the HEU downblending generally cannot contribute to the waste management problem posed by the existing large stockpiles of depleted uranium. At present, 95 percent of the world's stocks of depleted uranium remain in secure storage.{{citation needed|date=January 2020}}
A major downblending undertaking called the [[Megatons to Megawatts Program]] converts ex-Soviet weapons-grade HEU to fuel for U.S. commercial power reactors. From 1995 through mid-2005, 250 tonnes of high-enriched uranium (enough for 10,000 warheads) was recycled into low-enriched-uranium. The goal is to recycle 500 tonnes by 2013. The decommissioning programme of Russian nuclear warheads accounted for about 13% of total world requirement for enriched uranium leading up to 2008.<ref name="Lodge" />
The [[United States Enrichment Corporation]] has been involved in the disposition of a portion of the 174.3 tonnes of highly enriched uranium (HEU) that the U.S. government declared as surplus military material in 1996. Through the U.S. HEU Downblending Program, this HEU material, taken primarily from dismantled U.S. nuclear warheads, was recycled into low-enriched uranium (LEU) fuel, used by [[nuclear power plants]] to generate electricity.<ref>{{cite web|url = http://www.usec.com/v2001_02/HTML/Megatons_DOEstatus.asp|date = 1 May 2000 |title = Status Report: USEC-DOE Megatons to Megawatts Program|archiveurl=https://web.archive.org/web/20010406102039/http://www.usec.com/v2001_02/HTML/Megatons_DOEstatus.asp |archivedate=6 April 2001|publisher = USEC.com }}</ref><ref>{{cite web|title =Megatons to Megawatts|website = centrusenergy.com|date = December 2013|url= https://www.centrusenergy.com/who-we-are/history/megatons-to-megawatts/}}</ref>
==Global enrichment facilities==
The following countries are known to operate enrichment facilities: Argentina, Brazil, China, France, Germany, India, Iran, Japan, the Netherlands, North Korea, Pakistan, Russia, the United Kingdom, and the United States.<ref name=IEER-2004>{{Cite book|url=http://www.ieer.org/reports/uranium/enrichment.pdf|title=Uranium enrichment|author1=Arjun Makhijani |author2=Lois Chalmers |author3=Brice Smith |date=15 October 2004|publisher=Institute for Energy and Environmental Research|accessdate=21 November 2009}}</ref><ref>{{cite report |page=730 |url=http://www.aph.gov.au/binaries/house/committee/isr/uranium/report/fullreport.pdf |title=Australia's uranium - Greenhouse friendly fuel for an energy hungry world |work=Standing Committee on Industry and Resources |publisher=The Parliament of the Commonwealth of Australia |date=November 2006 |accessdate=3 April 2015}}</ref> Belgium, Iran, Italy, and Spain hold an investment interest in the French [[Eurodif]] enrichment plant, with [[Dominique Lorentz#Eurodif and Iran's nuclear program|Iran's holding]] entitling it to 10% of the enriched uranium output. Countries that had enrichment programs in the past include Libya and South Africa, although Libya's facility was never operational.<ref>{{cite news|url=http://news.bbc.co.uk/1/hi/world/middle_east/5278806.stm | title=Q&A: Uranium enrichment | author=BBC | date = 1 September 2006 | accessdate=3 January 2010 | work=BBC News}}</ref> Australia has developed a [[Atomic vapor laser isotope separation|laser enrichment]] process known as SILEX, which it intends to pursue through financial investment in a U.S. commercial venture by General Electric.<ref>{{cite news|url=http://www.smh.com.au/news/national/laser-enrichment-could-cut-cost-of-nuclear-power/2006/05/26/1148524888448.html|title=Laser enrichment could cut cost of nuclear power|newspaper=The Sydney Morning Herald|date=26 May 2006}}</ref> It has also been claimed that Israel has a uranium enrichment program housed at the [[Negev Nuclear Research Center]] site near [[Dimona]].<ref name=nwa-19971210>{{cite web|url=http://nuclearweaponarchive.org/Israel/|date=10 December 1997|title=Israel's Nuclear Weapons Program|publisher=Nuclear Weapon Archive|accessdate=7 October 2007}}</ref>
==Codename==
During the [[Manhattan Project]] weapons-grade highly enriched uranium was given the codename '''oralloy''',{{citation needed|date=January 2020}} a shortened version of [[Oak Ridge, Tennessee|Oak Ridge]] [[alloy]],{{citation needed|date=January 2020}} after the location of the plants where the uranium was enriched. The term oralloy is still occasionally used to refer to enriched uranium.
==See also==
* [[List of laser articles]]
* [[MOX fuel]]
* [[Nuclear fuel bank]]
* [[Orano]]
* [[Uranium market]]
* [[Uranium mining]]
==References==
{{reflist}}
==External links==
{{Wiktionary}}
* [https://web.archive.org/web/20090531024234/http://alsos.wlu.edu/qsearch.aspx?browse=science%2FEnriching+Uranium Annotated bibliography on enriched uranium from the Alsos Digital Library for Nuclear Issues]
* [http://www.silex.com.au Silex Systems Ltd]
* [http://world-nuclear.org/info/inf28.html Uranium Enrichment], World Nuclear Association
* [https://fas.org/sgp/othergov/doe/heu/index.html Overview and history of U.S. HEU production]
* [https://web.archive.org/web/20070303234531/http://www.huliq.com/tags/uranium-enrichment News Resource on Uranium Enrichment]
* [http://www.chemcases.com/nuclear/nc-07.htm Nuclear Chemistry-Uranium Enrichment]
* [https://web.archive.org/web/20110613105504/http://www.neimagazine.com/story.asp?storyCode=2050947 A busy year for SWU (a 2008 review of the commercial enrichment marketplace)], Nuclear Engineering International, 1 September 2008
* [https://web.archive.org/web/20110727073116/http://books.sipri.org/product_info?c_product_id=286 ''Uranium Enrichment and Nuclear Weapon Proliferation'', by Allan S. Krass, Peter Boskma, Boelie Elzen and Wim A. Smit, 296 pp., published for SIPRI by Taylor and Francis Ltd, London, 1983]
* {{cite web|last=Poliakoff|first=Martyn|title=How do you enrich Uranium?|url=http://www.periodicvideos.com/videos/feature_uranium_enrichment.htm|work=[[The Periodic Table of Videos]]|publisher=[[University of Nottingham]]|authorlink=Martyn Poliakoff|year=2009}}
* {{cite web|last1=Gilinsky|first=V.|last2=Hoehn|first2=W.|title=The Military Significance of Small Uranium Enrichment Facilities Fed with Low-Enrichment Uranium (Redacted)|url=http://oai.dtic.mil/oai/oai?verb=getRecord&metadataPrefix=html&identifier=ADA613260|publisher=[[RAND Corporation]]|date=December 1969|website=[[Defense Technical Information Center]]|access-date=12 February 2016|archive-url=https://web.archive.org/web/20160216062519/http://oai.dtic.mil/oai/oai?verb=getRecord&metadataPrefix=html&identifier=ADA613260|archive-date=16 February 2016|url-status=dead}}
{{Nuclear Technology}}
{{DEFAULTSORT:Enriched Uranium}}
[[Category:Isotope separation]]
[[Category:Nuclear fuels]]
[[Category:Nuclear materials|Uranium, Enriched]]
[[Category:Nuclear weapon design]]
[[Category:Uranium]]' |
Unified diff of changes made by edit (edit_diff ) | '@@ -12,31 +12,5 @@
==Grades==
-Uranium as it is taken directly from the Earth is not suitable as fuel for most nuclear reactors and requires additional processes to make it usable. Uranium is mined either underground or in an open pit depending on the depth at which it is found. After the [[uranium ore]] is mined, it must go through a milling process to extract the uranium from the ore.
-
-This is accomplished by a combination of chemical processes with the end product being concentrated uranium oxide, which is known as "[[yellowcake]]", contains roughly 60% uranium whereas the ore typically contains less than 1% uranium and as little as 0.1% uranium.
-
-After the milling process is complete, the uranium must next undergo a process of conversion, "to either [[uranium dioxide]], which can be used as the fuel for those types of reactors that do not require enriched uranium, or into [[uranium hexafluoride]], which can be enriched to produce fuel for the majority of types of reactors".<ref>{{cite web|url=https://www.hsdl.org/?view&did=770258 |title=Radiological Sources of Potential Exposure and/or Contamination |publisher=U.S. Army Center for Health Promotion and Preventive Medicine |page=27 |date=June 1999 |access-date=1 July 2019}}</ref> Naturally-occurring uranium is made of a mixture of <sup>235</sup>U and <sup>238</sup>U. The <sup>235</sup>U is [[fissile]], meaning it is easily split with [[Neutron|neutrons]] while the remainder is <sup>238</sup>U, but in nature, more than 99% of the extracted ore is <sup>238</sup>U. Most nuclear reactors require enriched uranium, which is uranium with higher concentrations of <sup>235</sup>U ranging between 3.5% and 4.5%. There are two commercial enrichment processes: [[gaseous diffusion]] and [[gas centrifugation]]. Both enrichment processes involve the use of uranium hexafluoride and produce enriched uranium oxide.
-
-[[File:LEUPowder.jpg|thumb|A drum of [[yellowcake]] (a mixture of uranium precipitates)]]
-
-===Reprocessed uranium (RepU)===
-{{Main|Reprocessed uranium}}
-
-''Reprocessed uranium'' (RepU) is a product of [[nuclear fuel cycle]]s involving [[nuclear reprocessing]] of [[spent fuel]]. RepU recovered from [[light water reactor]] (LWR) spent fuel typically contains slightly more <sup>235</sup>U than [[natural uranium]], and therefore could be used to fuel reactors that customarily use natural uranium as fuel, such as [[CANDU reactor]]s. It also contains the undesirable isotope [[uranium-236]], which undergoes [[neutron capture]], wasting neutrons (and requiring higher <sup>235</sup>U enrichment) and creating [[neptunium-237]], which would be one of the more mobile and troublesome radionuclides in [[deep geological repository]] disposal of nuclear waste.
-
-===Low enriched uranium (LEU)===
-''Low enriched uranium'' (LEU) has a lower than 20% concentration of <sup>235</sup>U; for instance, in commercial LWR, the most prevalent power reactors in the world, uranium is enriched to 3 to 5% <sup>235</sup>U. High-assay LEU is enriched from 5–20%.<ref>{{Cite web|url=https://www.energy.gov/sites/prod/files/2019/04/f61/HALEU%20Report%20to%20NEAC%20Committee%203-28-19%20%28FINAL%29.pdf|title=High-assay low enriched uranium|last=Herczeg|first=John W.|date=March 28, 2019|website=energy.gov|url-status=live|archive-url=|archive-date=|access-date=}}</ref> Fresh LEU used in [[research reactor]]s is usually enriched 12% to 19.75% <sup>235</sup>U, the latter concentration is used to replace HEU fuels when converting to LEU.<ref>{{cite journal |url=http://www.princeton.edu/~aglaser/2005aglaser_why20percent.pdf |title=About the Enrichment Limit for Research Reactor Conversion : Why 20%? |author=Alexander Glaser |publisher=Princeton University |date=6 November 2005 |accessdate=18 April 2014}}</ref>
-
-===Highly enriched uranium (HEU)===
-[[File:HEUraniumC.jpg|thumb|A [[billet (bar stock)|billet]] of highly enriched uranium metal]]
-
-''Highly enriched uranium'' (HEU) has a 20% or higher concentration of <sup>235</sup>U. The fissile uranium in [[nuclear weapon]] primaries usually contains 85% or more of <sup>235</sup>U known as [[weapons-grade]], though theoretically for an [[nuclear weapon design|implosion design]], a minimum of 20% could be sufficient (called weapon-usable) although it would require hundreds of kilograms of material and "would not be practical to design";<ref name="DefWpnsUsable">{{cite web |url= http://web.ornl.gov/info/reports/1998/3445606060721.pdf |title= Definition of Weapons-Usable Uranium-233 |last1= Forsberg |first1= C. W. |last2= Hopper |first2= C. M. |last3= Richter |first3= J. L. |last4= Vantine |first4= H. C. |date= March 1998 |work= ORNL/TM-13517 |publisher= Oak Ridge National Laboratories |accessdate= 30 October 2013 |url-status= dead |archiveurl= https://web.archive.org/web/20131102011417/http://web.ornl.gov/info/reports/1998/3445606060721.pdf |archivedate= 2 November 2013 |df= dmy-all }}</ref><ref name="NWFAQ">{{cite web |url= http://www.nuclearweaponarchive.org/Nwfaq/Nfaq4-1.html#Nfaq4.1.7.1 |title= Nuclear Weapons FAQ, Section 4.1.7.1: Nuclear Design Principles – Highly Enriched Uranium |last1= Sublette |first1= Carey |date= 4 October 1996 |work= Nuclear Weapons FAQ |accessdate=2 October 2010}}</ref> even lower enrichment is hypothetically possible, but as the enrichment percentage decreases the [[Critical mass (nuclear)|critical mass]] for unmoderated [[fast neutron]]s rapidly increases, with for example, an [[infinity|infinite]] mass of 5.4% <sup>235</sup>U being required.<ref name="DefWpnsUsable"/> For [[Criticality (status)|criticality]] experiments, enrichment of uranium to over 97% has been accomplished.<ref>{{cite journal |last=Mosteller |first=R.D. |year=1994 |title=Detailed Reanalysis of a Benchmark Critical Experiment: Water-Reflected Enriched-Uranium Sphere |journal=Los Alamos Technical Paper |issue=LA–UR–93–4097 |page=2 |url=http://www.osti.gov/bridge/servlets/purl/10120434-rruwqp/native/10120434.PDF |accessdate=19 December 2007 |quote=The enrichment of the pin and of one of the hemispheres was 97.67 w/o, while the enrichment of the other hemisphere was 97.68 w/o.|doi=10.2172/10120434 }}</ref>
-
-The very first uranium bomb, [[Little Boy]], dropped by the [[United States]] on [[Hiroshima]] in 1945, used 64 kilograms of 80% enriched uranium. Wrapping the weapon's fissile core in a [[neutron reflector]] (which is standard on all nuclear explosives) can dramatically reduce the critical mass. Because the core was surrounded by a good neutron reflector, at explosion it comprised almost 2.5 critical masses. Neutron reflectors, compressing the fissile core via implosion, [[fusion boosting]], and "tamping", which slows the expansion of the fissioning core with inertia, allow [[nuclear weapon design]]s that use less than what would be one bare-sphere critical mass at normal density. The presence of too much of the <sup>238</sup>U isotope inhibits the runaway [[nuclear chain reaction]] that is responsible for the weapon's power. The critical mass for 85% highly enriched uranium is about {{convert|50|kg}}, which at normal density would be a sphere about {{convert|17|cm}} in diameter.
-
-Later US nuclear weapons usually use [[plutonium-239]] in the primary stage, but the jacket or tamper secondary stage, which is compressed by the primary nuclear explosion often uses HEU with enrichment between 40% and 80%<ref>{{cite web|url=http://nuclearweaponarchive.org/Nwfaq/Nfaq6.html#nfaq6.2 |title=Nuclear Weapons FAQ |accessdate=26 January 2013}}</ref>
-along with the [[nuclear fusion|fusion]] fuel [[lithium deuteride]]. For the secondary of a large nuclear weapon, the higher critical mass of less-enriched uranium can be an advantage as it allows the core at explosion time to contain a larger amount of fuel. The <sup>238</sup>U is not said to be fissile but still is fissionable by fast neutrons (>2 MeV) such as the ones produced during D-T fusion.
-
-HEU is also used in [[fast neutron reactor]]s, whose cores require about 20% or more of fissile material, as well as in [[Nuclear marine propulsion|naval reactors]], where it often contains at least 50% <sup>235</sup>U, but typically does not exceed 90%. The [[Fermi 1|Fermi-1]] commercial fast reactor prototype used HEU with 26.5% <sup>235</sup>U. Significant quantities of HEU are used in the production of [[medical isotopes]], for example [[molybdenum-99]] for [[technetium-99m generator]]s.<ref>{{cite journal |title=Feasibility of Eliminating the Use of Highly Enriched Uranium in the Production of Medical Radioisotopes |author1=Frank N. Von Hippel |author2=Laura H. Kahn |journal=Science & Global Security |volume=14 |issue= 2 & 3|date=December 2006 |pages=151–162 |doi=10.1080/08929880600993071 |bibcode=2006S&GS...14..151V }}</ref>
+Uranium as it is taken directly from the Earth is not suitable as fuel for most nuclear reactors and requires additional processes to make it usable. Uranium is mined either underground or in an open pit depending on the depth at which it is found. After the [[uranium ore]] is mined, it must go through a milling process to extract the uranium from the ore.be used to fuel reactors that customarily use natural uranium as fuel, such as [[CANDU reactor]]s. It also contains the undesirable isotope [[uranium-236]], which undergoes [[neutron capture]], wasting neutrons (and requiring higher <sup>235</sup>U enrichment) and creating [[neptunium-237]], which would be one of the more mobile and troublesome radionuclides in [[deep geological repository]] disposal of nuclear waste.
==Enrichment methods==
' |
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0 => 'Uranium as it is taken directly from the Earth is not suitable as fuel for most nuclear reactors and requires additional processes to make it usable. Uranium is mined either underground or in an open pit depending on the depth at which it is found. After the [[uranium ore]] is mined, it must go through a milling process to extract the uranium from the ore.be used to fuel reactors that customarily use natural uranium as fuel, such as [[CANDU reactor]]s. It also contains the undesirable isotope [[uranium-236]], which undergoes [[neutron capture]], wasting neutrons (and requiring higher <sup>235</sup>U enrichment) and creating [[neptunium-237]], which would be one of the more mobile and troublesome radionuclides in [[deep geological repository]] disposal of nuclear waste.'
] |
Lines removed in edit (removed_lines ) | [
0 => 'Uranium as it is taken directly from the Earth is not suitable as fuel for most nuclear reactors and requires additional processes to make it usable. Uranium is mined either underground or in an open pit depending on the depth at which it is found. After the [[uranium ore]] is mined, it must go through a milling process to extract the uranium from the ore.',
1 => '',
2 => 'This is accomplished by a combination of chemical processes with the end product being concentrated uranium oxide, which is known as "[[yellowcake]]", contains roughly 60% uranium whereas the ore typically contains less than 1% uranium and as little as 0.1% uranium.',
3 => '',
4 => 'After the milling process is complete, the uranium must next undergo a process of conversion, "to either [[uranium dioxide]], which can be used as the fuel for those types of reactors that do not require enriched uranium, or into [[uranium hexafluoride]], which can be enriched to produce fuel for the majority of types of reactors".<ref>{{cite web|url=https://www.hsdl.org/?view&did=770258 |title=Radiological Sources of Potential Exposure and/or Contamination |publisher=U.S. Army Center for Health Promotion and Preventive Medicine |page=27 |date=June 1999 |access-date=1 July 2019}}</ref> Naturally-occurring uranium is made of a mixture of <sup>235</sup>U and <sup>238</sup>U. The <sup>235</sup>U is [[fissile]], meaning it is easily split with [[Neutron|neutrons]] while the remainder is <sup>238</sup>U, but in nature, more than 99% of the extracted ore is <sup>238</sup>U. Most nuclear reactors require enriched uranium, which is uranium with higher concentrations of <sup>235</sup>U ranging between 3.5% and 4.5%. There are two commercial enrichment processes: [[gaseous diffusion]] and [[gas centrifugation]]. Both enrichment processes involve the use of uranium hexafluoride and produce enriched uranium oxide.',
5 => '',
6 => '[[File:LEUPowder.jpg|thumb|A drum of [[yellowcake]] (a mixture of uranium precipitates)]]',
7 => '',
8 => '===Reprocessed uranium (RepU)===',
9 => '{{Main|Reprocessed uranium}}',
10 => '',
11 => '''Reprocessed uranium'' (RepU) is a product of [[nuclear fuel cycle]]s involving [[nuclear reprocessing]] of [[spent fuel]]. RepU recovered from [[light water reactor]] (LWR) spent fuel typically contains slightly more <sup>235</sup>U than [[natural uranium]], and therefore could be used to fuel reactors that customarily use natural uranium as fuel, such as [[CANDU reactor]]s. It also contains the undesirable isotope [[uranium-236]], which undergoes [[neutron capture]], wasting neutrons (and requiring higher <sup>235</sup>U enrichment) and creating [[neptunium-237]], which would be one of the more mobile and troublesome radionuclides in [[deep geological repository]] disposal of nuclear waste.',
12 => '',
13 => '===Low enriched uranium (LEU)===',
14 => '''Low enriched uranium'' (LEU) has a lower than 20% concentration of <sup>235</sup>U; for instance, in commercial LWR, the most prevalent power reactors in the world, uranium is enriched to 3 to 5% <sup>235</sup>U. High-assay LEU is enriched from 5–20%.<ref>{{Cite web|url=https://www.energy.gov/sites/prod/files/2019/04/f61/HALEU%20Report%20to%20NEAC%20Committee%203-28-19%20%28FINAL%29.pdf|title=High-assay low enriched uranium|last=Herczeg|first=John W.|date=March 28, 2019|website=energy.gov|url-status=live|archive-url=|archive-date=|access-date=}}</ref> Fresh LEU used in [[research reactor]]s is usually enriched 12% to 19.75% <sup>235</sup>U, the latter concentration is used to replace HEU fuels when converting to LEU.<ref>{{cite journal |url=http://www.princeton.edu/~aglaser/2005aglaser_why20percent.pdf |title=About the Enrichment Limit for Research Reactor Conversion : Why 20%? |author=Alexander Glaser |publisher=Princeton University |date=6 November 2005 |accessdate=18 April 2014}}</ref>',
15 => '',
16 => '===Highly enriched uranium (HEU)===',
17 => '[[File:HEUraniumC.jpg|thumb|A [[billet (bar stock)|billet]] of highly enriched uranium metal]]',
18 => '',
19 => '''Highly enriched uranium'' (HEU) has a 20% or higher concentration of <sup>235</sup>U. The fissile uranium in [[nuclear weapon]] primaries usually contains 85% or more of <sup>235</sup>U known as [[weapons-grade]], though theoretically for an [[nuclear weapon design|implosion design]], a minimum of 20% could be sufficient (called weapon-usable) although it would require hundreds of kilograms of material and "would not be practical to design";<ref name="DefWpnsUsable">{{cite web |url= http://web.ornl.gov/info/reports/1998/3445606060721.pdf |title= Definition of Weapons-Usable Uranium-233 |last1= Forsberg |first1= C. W. |last2= Hopper |first2= C. M. |last3= Richter |first3= J. L. |last4= Vantine |first4= H. C. |date= March 1998 |work= ORNL/TM-13517 |publisher= Oak Ridge National Laboratories |accessdate= 30 October 2013 |url-status= dead |archiveurl= https://web.archive.org/web/20131102011417/http://web.ornl.gov/info/reports/1998/3445606060721.pdf |archivedate= 2 November 2013 |df= dmy-all }}</ref><ref name="NWFAQ">{{cite web |url= http://www.nuclearweaponarchive.org/Nwfaq/Nfaq4-1.html#Nfaq4.1.7.1 |title= Nuclear Weapons FAQ, Section 4.1.7.1: Nuclear Design Principles – Highly Enriched Uranium |last1= Sublette |first1= Carey |date= 4 October 1996 |work= Nuclear Weapons FAQ |accessdate=2 October 2010}}</ref> even lower enrichment is hypothetically possible, but as the enrichment percentage decreases the [[Critical mass (nuclear)|critical mass]] for unmoderated [[fast neutron]]s rapidly increases, with for example, an [[infinity|infinite]] mass of 5.4% <sup>235</sup>U being required.<ref name="DefWpnsUsable"/> For [[Criticality (status)|criticality]] experiments, enrichment of uranium to over 97% has been accomplished.<ref>{{cite journal |last=Mosteller |first=R.D. |year=1994 |title=Detailed Reanalysis of a Benchmark Critical Experiment: Water-Reflected Enriched-Uranium Sphere |journal=Los Alamos Technical Paper |issue=LA–UR–93–4097 |page=2 |url=http://www.osti.gov/bridge/servlets/purl/10120434-rruwqp/native/10120434.PDF |accessdate=19 December 2007 |quote=The enrichment of the pin and of one of the hemispheres was 97.67 w/o, while the enrichment of the other hemisphere was 97.68 w/o.|doi=10.2172/10120434 }}</ref>',
20 => '',
21 => 'The very first uranium bomb, [[Little Boy]], dropped by the [[United States]] on [[Hiroshima]] in 1945, used 64 kilograms of 80% enriched uranium. Wrapping the weapon's fissile core in a [[neutron reflector]] (which is standard on all nuclear explosives) can dramatically reduce the critical mass. Because the core was surrounded by a good neutron reflector, at explosion it comprised almost 2.5 critical masses. Neutron reflectors, compressing the fissile core via implosion, [[fusion boosting]], and "tamping", which slows the expansion of the fissioning core with inertia, allow [[nuclear weapon design]]s that use less than what would be one bare-sphere critical mass at normal density. The presence of too much of the <sup>238</sup>U isotope inhibits the runaway [[nuclear chain reaction]] that is responsible for the weapon's power. The critical mass for 85% highly enriched uranium is about {{convert|50|kg}}, which at normal density would be a sphere about {{convert|17|cm}} in diameter.',
22 => '',
23 => 'Later US nuclear weapons usually use [[plutonium-239]] in the primary stage, but the jacket or tamper secondary stage, which is compressed by the primary nuclear explosion often uses HEU with enrichment between 40% and 80%<ref>{{cite web|url=http://nuclearweaponarchive.org/Nwfaq/Nfaq6.html#nfaq6.2 |title=Nuclear Weapons FAQ |accessdate=26 January 2013}}</ref>',
24 => 'along with the [[nuclear fusion|fusion]] fuel [[lithium deuteride]]. For the secondary of a large nuclear weapon, the higher critical mass of less-enriched uranium can be an advantage as it allows the core at explosion time to contain a larger amount of fuel. The <sup>238</sup>U is not said to be fissile but still is fissionable by fast neutrons (>2 MeV) such as the ones produced during D-T fusion.',
25 => '',
26 => 'HEU is also used in [[fast neutron reactor]]s, whose cores require about 20% or more of fissile material, as well as in [[Nuclear marine propulsion|naval reactors]], where it often contains at least 50% <sup>235</sup>U, but typically does not exceed 90%. The [[Fermi 1|Fermi-1]] commercial fast reactor prototype used HEU with 26.5% <sup>235</sup>U. Significant quantities of HEU are used in the production of [[medical isotopes]], for example [[molybdenum-99]] for [[technetium-99m generator]]s.<ref>{{cite journal |title=Feasibility of Eliminating the Use of Highly Enriched Uranium in the Production of Medical Radioisotopes |author1=Frank N. Von Hippel |author2=Laura H. Kahn |journal=Science & Global Security |volume=14 |issue= 2 & 3|date=December 2006 |pages=151–162 |doi=10.1080/08929880600993071 |bibcode=2006S&GS...14..151V }}</ref>'
] |
All external links added in the edit (added_links ) | [] |
All external links removed in the edit (removed_links ) | [
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</p>
<div class="thumb tright"><div class="thumbinner" style="width:222px;"><a href="/enwiki/wiki/File:Uranium_enrichment_proportions.svg" class="image"><img alt="" src="/upwiki/wikipedia/commons/thumb/2/25/Uranium_enrichment_proportions.svg/220px-Uranium_enrichment_proportions.svg.png" decoding="async" width="220" height="645" class="thumbimage" srcset="/upwiki/wikipedia/commons/thumb/2/25/Uranium_enrichment_proportions.svg/330px-Uranium_enrichment_proportions.svg.png 1.5x, /upwiki/wikipedia/commons/thumb/2/25/Uranium_enrichment_proportions.svg/440px-Uranium_enrichment_proportions.svg.png 2x" data-file-width="750" data-file-height="2200" /></a> <div class="thumbcaption"><div class="magnify"><a href="/enwiki/wiki/File:Uranium_enrichment_proportions.svg" class="internal" title="Enlarge"></a></div>Proportions of uranium-238 (blue) and uranium-235 (red) found naturally versus enriched grades</div></div></div>
<p><b>Enriched uranium</b> is a type of <a href="/enwiki/wiki/Uranium" title="Uranium">uranium</a> in which the percent composition of <a href="/enwiki/wiki/Uranium-235" title="Uranium-235">uranium-235</a> (written <sup>235</sup>U) has been increased through the process of <a href="/enwiki/wiki/Isotope_separation" title="Isotope separation">isotope separation</a>. Naturally occurring uranium is composed of three major isotopes: <a href="/enwiki/wiki/Uranium-238" title="Uranium-238">uranium-238</a> (<sup>238</sup>U with 99.2739–99.2752% <a href="/enwiki/wiki/Natural_abundance" title="Natural abundance">natural abundance</a>), <a href="/enwiki/wiki/Uranium-235" title="Uranium-235">uranium-235</a> (<sup>235</sup>U, 0.7198–0.7202%), and <a href="/enwiki/wiki/Uranium-234" title="Uranium-234">uranium-234</a> (<sup>234</sup>U, 0.0050–0.0059%).<sup id="cite_ref-1" class="reference"><a href="#cite_note-1">[1]</a></sup> <sup>235</sup>U is the only <a href="/enwiki/wiki/Primordial_nuclide" title="Primordial nuclide">nuclide existing in nature</a> (in any appreciable amount) that is <a href="/enwiki/wiki/Fissile" class="mw-redirect" title="Fissile">fissile</a> with <a href="/enwiki/wiki/Thermal_neutron" class="mw-redirect" title="Thermal neutron">thermal neutrons</a>.<sup id="cite_ref-2" class="reference"><a href="#cite_note-2">[2]</a></sup>
</p><p>Enriched uranium is a critical component for both civil <a href="/enwiki/wiki/Nuclear_power" title="Nuclear power">nuclear power generation</a> and military <a href="/enwiki/wiki/Nuclear_weapon" title="Nuclear weapon">nuclear weapons</a>. The <a href="/enwiki/wiki/International_Atomic_Energy_Agency" title="International Atomic Energy Agency">International Atomic Energy Agency</a> attempts to monitor and control enriched uranium supplies and processes in its efforts to ensure nuclear power generation safety and curb <a href="/enwiki/wiki/Nuclear_proliferation" title="Nuclear proliferation">nuclear weapons proliferation</a>.
</p><p>There are about 2,000 <a href="/enwiki/wiki/Tonne" title="Tonne">tonnes</a> (t, Mg) of highly enriched uranium in the world,<sup id="cite_ref-3" class="reference"><a href="#cite_note-3">[3]</a></sup> produced mostly for <a href="/enwiki/wiki/Nuclear_power" title="Nuclear power">nuclear power</a>, nuclear weapons, <a href="/enwiki/wiki/Nuclear_marine_propulsion" title="Nuclear marine propulsion">naval propulsion</a>, and smaller quantities for <a href="/enwiki/wiki/Research_reactor" title="Research reactor">research reactors</a>.
</p><p>The <sup>238</sup>U remaining after enrichment is known as <a href="/enwiki/wiki/Depleted_uranium" title="Depleted uranium">depleted uranium</a> (DU), and is considerably less <a href="/enwiki/wiki/Radioactive" class="mw-redirect" title="Radioactive">radioactive</a> than even natural uranium, though still very dense and extremely hazardous in granulated form – such granules are a natural by-product of the shearing action that makes it useful for <a href="/enwiki/wiki/Vehicle_armor" class="mw-redirect" title="Vehicle armor">armor</a>-<a href="/enwiki/wiki/Staballoy" title="Staballoy">penetrating weapons</a> and <a href="/enwiki/wiki/Radiation_shielding" class="mw-redirect" title="Radiation shielding">radiation shielding</a>.
</p>
<style data-mw-deduplicate="TemplateStyles:r886046785">.mw-parser-output .toclimit-2 .toclevel-1 ul,.mw-parser-output .toclimit-3 .toclevel-2 ul,.mw-parser-output .toclimit-4 .toclevel-3 ul,.mw-parser-output .toclimit-5 .toclevel-4 ul,.mw-parser-output .toclimit-6 .toclevel-5 ul,.mw-parser-output .toclimit-7 .toclevel-6 ul{display:none}</style><div class="toclimit-3"><div id="toc" class="toc" role="navigation" aria-labelledby="mw-toc-heading"><input type="checkbox" role="button" id="toctogglecheckbox" class="toctogglecheckbox" style="display:none" /><div class="toctitle" lang="en" dir="ltr"><h2 id="mw-toc-heading">Contents</h2><span class="toctogglespan"><label class="toctogglelabel" for="toctogglecheckbox"></label></span></div>
<ul>
<li class="toclevel-1 tocsection-1"><a href="#Grades"><span class="tocnumber">1</span> <span class="toctext">Grades</span></a></li>
<li class="toclevel-1 tocsection-2"><a href="#Enrichment_methods"><span class="tocnumber">2</span> <span class="toctext">Enrichment methods</span></a>
<ul>
<li class="toclevel-2 tocsection-3"><a href="#Diffusion_techniques"><span class="tocnumber">2.1</span> <span class="toctext">Diffusion techniques</span></a>
<ul>
<li class="toclevel-3 tocsection-4"><a href="#Gaseous_diffusion"><span class="tocnumber">2.1.1</span> <span class="toctext">Gaseous diffusion</span></a></li>
<li class="toclevel-3 tocsection-5"><a href="#Thermal_diffusion"><span class="tocnumber">2.1.2</span> <span class="toctext">Thermal diffusion</span></a></li>
</ul>
</li>
<li class="toclevel-2 tocsection-6"><a href="#Centrifuge_techniques"><span class="tocnumber">2.2</span> <span class="toctext">Centrifuge techniques</span></a>
<ul>
<li class="toclevel-3 tocsection-7"><a href="#Gas_centrifuge"><span class="tocnumber">2.2.1</span> <span class="toctext">Gas centrifuge</span></a></li>
<li class="toclevel-3 tocsection-8"><a href="#Zippe_centrifuge"><span class="tocnumber">2.2.2</span> <span class="toctext">Zippe centrifuge</span></a></li>
</ul>
</li>
<li class="toclevel-2 tocsection-9"><a href="#Laser_techniques"><span class="tocnumber">2.3</span> <span class="toctext">Laser techniques</span></a>
<ul>
<li class="toclevel-3 tocsection-10"><a href="#Atomic_vapor_laser_isotope_separation_(AVLIS)"><span class="tocnumber">2.3.1</span> <span class="toctext">Atomic vapor laser isotope separation (AVLIS)</span></a></li>
<li class="toclevel-3 tocsection-11"><a href="#Molecular_laser_isotope_separation_(MLIS)"><span class="tocnumber">2.3.2</span> <span class="toctext">Molecular laser isotope separation (MLIS)</span></a></li>
<li class="toclevel-3 tocsection-12"><a href="#Separation_of_isotopes_by_laser_excitation_(SILEX)"><span class="tocnumber">2.3.3</span> <span class="toctext">Separation of isotopes by laser excitation (SILEX)</span></a></li>
</ul>
</li>
<li class="toclevel-2 tocsection-13"><a href="#Other_techniques"><span class="tocnumber">2.4</span> <span class="toctext">Other techniques</span></a>
<ul>
<li class="toclevel-3 tocsection-14"><a href="#Aerodynamic_processes"><span class="tocnumber">2.4.1</span> <span class="toctext">Aerodynamic processes</span></a></li>
<li class="toclevel-3 tocsection-15"><a href="#Electromagnetic_isotope_separation"><span class="tocnumber">2.4.2</span> <span class="toctext">Electromagnetic isotope separation</span></a></li>
<li class="toclevel-3 tocsection-16"><a href="#Chemical_methods"><span class="tocnumber">2.4.3</span> <span class="toctext">Chemical methods</span></a></li>
<li class="toclevel-3 tocsection-17"><a href="#Plasma_separation"><span class="tocnumber">2.4.4</span> <span class="toctext">Plasma separation</span></a></li>
</ul>
</li>
</ul>
</li>
<li class="toclevel-1 tocsection-18"><a href="#Separative_work_unit"><span class="tocnumber">3</span> <span class="toctext">Separative work unit</span></a></li>
<li class="toclevel-1 tocsection-19"><a href="#Cost_issues"><span class="tocnumber">4</span> <span class="toctext">Cost issues</span></a></li>
<li class="toclevel-1 tocsection-20"><a href="#Downblending"><span class="tocnumber">5</span> <span class="toctext">Downblending</span></a></li>
<li class="toclevel-1 tocsection-21"><a href="#Global_enrichment_facilities"><span class="tocnumber">6</span> <span class="toctext">Global enrichment facilities</span></a></li>
<li class="toclevel-1 tocsection-22"><a href="#Codename"><span class="tocnumber">7</span> <span class="toctext">Codename</span></a></li>
<li class="toclevel-1 tocsection-23"><a href="#See_also"><span class="tocnumber">8</span> <span class="toctext">See also</span></a></li>
<li class="toclevel-1 tocsection-24"><a href="#References"><span class="tocnumber">9</span> <span class="toctext">References</span></a></li>
<li class="toclevel-1 tocsection-25"><a href="#External_links"><span class="tocnumber">10</span> <span class="toctext">External links</span></a></li>
</ul>
</div>
</div>
<h2><span class="mw-headline" id="Grades">Grades</span><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/enwiki/w/index.php?title=Enriched_uranium&action=edit&section=1" title="Edit section: Grades">edit</a><span class="mw-editsection-bracket">]</span></span></h2>
<p>Uranium as it is taken directly from the Earth is not suitable as fuel for most nuclear reactors and requires additional processes to make it usable. Uranium is mined either underground or in an open pit depending on the depth at which it is found. After the <a href="/enwiki/wiki/Uranium_ore" title="Uranium ore">uranium ore</a> is mined, it must go through a milling process to extract the uranium from the ore.be used to fuel reactors that customarily use natural uranium as fuel, such as <a href="/enwiki/wiki/CANDU_reactor" title="CANDU reactor">CANDU reactors</a>. It also contains the undesirable isotope <a href="/enwiki/wiki/Uranium-236" title="Uranium-236">uranium-236</a>, which undergoes <a href="/enwiki/wiki/Neutron_capture" title="Neutron capture">neutron capture</a>, wasting neutrons (and requiring higher <sup>235</sup>U enrichment) and creating <a href="/enwiki/wiki/Neptunium-237" class="mw-redirect" title="Neptunium-237">neptunium-237</a>, which would be one of the more mobile and troublesome radionuclides in <a href="/enwiki/wiki/Deep_geological_repository" title="Deep geological repository">deep geological repository</a> disposal of nuclear waste.
</p>
<h2><span class="mw-headline" id="Enrichment_methods">Enrichment methods</span><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/enwiki/w/index.php?title=Enriched_uranium&action=edit&section=2" title="Edit section: Enrichment methods">edit</a><span class="mw-editsection-bracket">]</span></span></h2>
<p><a href="/enwiki/wiki/Isotope_separation" title="Isotope separation">Isotope separation</a> is difficult because two isotopes of the same element have nearly identical chemical properties, and can only be separated gradually using small mass differences. (<sup>235</sup>U is only 1.26% lighter than <sup>238</sup>U.) This problem is compounded by the fact that uranium is rarely separated in its atomic form, but instead as a compound (<sup>235</sup>UF<sub>6</sub> is only 0.852% lighter than <sup>238</sup>UF<sub>6</sub>.)
A <a href="/enwiki/wiki/Cascade_(chemical_engineering)" title="Cascade (chemical engineering)">cascade</a> of identical stages produces successively higher concentrations of <sup>235</sup>U. Each stage passes a slightly more concentrated product to the next stage and returns a slightly less concentrated residue to the previous stage.
</p><p>There are currently two generic commercial methods employed internationally for enrichment: <a href="/enwiki/wiki/Gaseous_diffusion" title="Gaseous diffusion">gaseous diffusion</a> (referred to as <i>first</i> generation) and <a href="/enwiki/wiki/Gas_centrifuge" title="Gas centrifuge">gas centrifuge</a> (<i>second</i> generation), which consumes only 2% to 2.5%<sup id="cite_ref-4" class="reference"><a href="#cite_note-4">[4]</a></sup> as much energy as gaseous diffusion (at least a "factor of 20" more efficient).<sup id="cite_ref-5" class="reference"><a href="#cite_note-5">[5]</a></sup> Some work is being done that would use <a href="/enwiki/wiki/Nuclear_magnetic_resonance" title="Nuclear magnetic resonance">nuclear resonance</a>; however there is no reliable evidence that any nuclear resonance processes have been scaled up to production.
</p>
<h3><span class="mw-headline" id="Diffusion_techniques">Diffusion techniques</span><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/enwiki/w/index.php?title=Enriched_uranium&action=edit&section=3" title="Edit section: Diffusion techniques">edit</a><span class="mw-editsection-bracket">]</span></span></h3>
<h4><span class="mw-headline" id="Gaseous_diffusion">Gaseous diffusion</span><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/enwiki/w/index.php?title=Enriched_uranium&action=edit&section=4" title="Edit section: Gaseous diffusion">edit</a><span class="mw-editsection-bracket">]</span></span></h4>
<div class="thumb tright"><div class="thumbinner" style="width:222px;"><a href="/enwiki/wiki/File:Gaseous_Diffusion_(44021367082)_(cropped).jpg" class="image"><img alt="" src="/upwiki/wikipedia/commons/thumb/d/d7/Gaseous_Diffusion_%2844021367082%29_%28cropped%29.jpg/220px-Gaseous_Diffusion_%2844021367082%29_%28cropped%29.jpg" decoding="async" width="220" height="114" class="thumbimage" srcset="/upwiki/wikipedia/commons/thumb/d/d7/Gaseous_Diffusion_%2844021367082%29_%28cropped%29.jpg/330px-Gaseous_Diffusion_%2844021367082%29_%28cropped%29.jpg 1.5x, /upwiki/wikipedia/commons/thumb/d/d7/Gaseous_Diffusion_%2844021367082%29_%28cropped%29.jpg/440px-Gaseous_Diffusion_%2844021367082%29_%28cropped%29.jpg 2x" data-file-width="772" data-file-height="399" /></a> <div class="thumbcaption"><div class="magnify"><a href="/enwiki/wiki/File:Gaseous_Diffusion_(44021367082)_(cropped).jpg" class="internal" title="Enlarge"></a></div>Gaseous diffusion uses semi-permeable membranes to separate enriched uranium</div></div></div>
<div role="note" class="hatnote navigation-not-searchable">Main article: <a href="/enwiki/wiki/Gaseous_diffusion" title="Gaseous diffusion">Gaseous diffusion</a></div>
<p>Gaseous diffusion is a technology used to produce enriched uranium by forcing gaseous <a href="/enwiki/wiki/Uranium_hexafluoride" title="Uranium hexafluoride">uranium hexafluoride</a> (<i>hex</i>) through <a href="/enwiki/wiki/Semi-permeable_membrane" class="mw-redirect" title="Semi-permeable membrane">semi-permeable membranes</a>. This produces a slight separation between the molecules containing <sup>235</sup>U and <sup>238</sup>U. Throughout the <a href="/enwiki/wiki/Cold_War" title="Cold War">Cold War</a>, gaseous diffusion played a major role as a uranium enrichment technique, and as of 2008 accounted for about 33% of enriched uranium production,<sup id="cite_ref-Lodge_6-0" class="reference"><a href="#cite_note-Lodge-6">[6]</a></sup> but in 2011 was deemed an obsolete technology that is steadily being replaced by the later generations of technology as the diffusion plants reach their ends-of-life.<sup id="cite_ref-7" class="reference"><a href="#cite_note-7">[7]</a></sup> In 2013, the <a href="/enwiki/wiki/Paducah_Gaseous_Diffusion_Plant" title="Paducah Gaseous Diffusion Plant">Paducah</a> facility in the US ceased operating, it was the last commercial <sup>235</sup>U gaseous diffusion plant in the world.<sup id="cite_ref-8" class="reference"><a href="#cite_note-8">[8]</a></sup>
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<h4><span class="mw-headline" id="Thermal_diffusion">Thermal diffusion</span><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/enwiki/w/index.php?title=Enriched_uranium&action=edit&section=5" title="Edit section: Thermal diffusion">edit</a><span class="mw-editsection-bracket">]</span></span></h4>
<p>Thermal diffusion uses the transfer of heat across a thin liquid or gas to accomplish isotope separation. The process exploits the fact that the lighter <sup>235</sup>U gas molecules will diffuse toward a hot surface, and the heavier <sup>238</sup>U gas molecules will diffuse toward a cold surface. The <a href="/enwiki/wiki/S-50_(Manhattan_Project)" title="S-50 (Manhattan Project)">S-50</a> plant at <a href="/enwiki/wiki/Oak_Ridge,_Tennessee" title="Oak Ridge, Tennessee">Oak Ridge, Tennessee</a> was used during <a href="/enwiki/wiki/World_War_II" title="World War II">World War II</a> to prepare feed material for the <a href="#Electromagnetic_isotope_separation">EMIS</a> process. It was abandoned in favor of gaseous diffusion.
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<h3><span class="mw-headline" id="Centrifuge_techniques">Centrifuge techniques</span><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/enwiki/w/index.php?title=Enriched_uranium&action=edit&section=6" title="Edit section: Centrifuge techniques">edit</a><span class="mw-editsection-bracket">]</span></span></h3>
<h4><span class="mw-headline" id="Gas_centrifuge">Gas centrifuge</span><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/enwiki/w/index.php?title=Enriched_uranium&action=edit&section=7" title="Edit section: Gas centrifuge">edit</a><span class="mw-editsection-bracket">]</span></span></h4>
<div role="note" class="hatnote navigation-not-searchable">Main article: <a href="/enwiki/wiki/Gas_centrifuge" title="Gas centrifuge">Gas centrifuge</a></div>
<div class="thumb tright"><div class="thumbinner" style="width:222px;"><a href="/enwiki/wiki/File:Gas_centrifuge_cascade.jpg" class="image"><img alt="" src="/upwiki/wikipedia/commons/thumb/6/69/Gas_centrifuge_cascade.jpg/220px-Gas_centrifuge_cascade.jpg" decoding="async" width="220" height="176" class="thumbimage" srcset="/upwiki/wikipedia/commons/thumb/6/69/Gas_centrifuge_cascade.jpg/330px-Gas_centrifuge_cascade.jpg 1.5x, /upwiki/wikipedia/commons/thumb/6/69/Gas_centrifuge_cascade.jpg/440px-Gas_centrifuge_cascade.jpg 2x" data-file-width="3200" data-file-height="2560" /></a> <div class="thumbcaption"><div class="magnify"><a href="/enwiki/wiki/File:Gas_centrifuge_cascade.jpg" class="internal" title="Enlarge"></a></div>A cascade of gas centrifuges at a U.S. enrichment plant</div></div></div>
<p>The gas centrifuge process uses a large number of rotating cylinders in series and parallel formations. Each cylinder's rotation creates a strong <a href="/enwiki/wiki/Centripetal_force" title="Centripetal force">centripetal force</a> so that the heavier gas molecules containing <sup>238</sup>U move tangentially toward the outside of the cylinder and the lighter gas molecules rich in <sup>235</sup>U collect closer to the center. It requires much less energy to achieve the same separation than the older gaseous diffusion process, which it has largely replaced and so is the current method of choice and is termed <i>second generation</i>. It has a separation factor per stage of 1.3 relative to gaseous diffusion of 1.005,<sup id="cite_ref-Lodge_6-1" class="reference"><a href="#cite_note-Lodge-6">[6]</a></sup> which translates to about one-fiftieth of the energy requirements. Gas centrifuge techniques produce close to 100% of the world's enriched uranium.
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<h4><span class="mw-headline" id="Zippe_centrifuge">Zippe centrifuge</span><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/enwiki/w/index.php?title=Enriched_uranium&action=edit&section=8" title="Edit section: Zippe centrifuge">edit</a><span class="mw-editsection-bracket">]</span></span></h4>
<div class="thumb tleft"><div class="thumbinner" style="width:172px;"><a href="/enwiki/wiki/File:Zippe-type_gas_centrifuge.svg" class="image"><img alt="" src="/upwiki/wikipedia/commons/thumb/2/27/Zippe-type_gas_centrifuge.svg/170px-Zippe-type_gas_centrifuge.svg.png" decoding="async" width="170" height="291" class="thumbimage" srcset="/upwiki/wikipedia/commons/thumb/2/27/Zippe-type_gas_centrifuge.svg/255px-Zippe-type_gas_centrifuge.svg.png 1.5x, /upwiki/wikipedia/commons/thumb/2/27/Zippe-type_gas_centrifuge.svg/340px-Zippe-type_gas_centrifuge.svg.png 2x" data-file-width="622" data-file-height="1066" /></a> <div class="thumbcaption"><div class="magnify"><a href="/enwiki/wiki/File:Zippe-type_gas_centrifuge.svg" class="internal" title="Enlarge"></a></div>Diagram of the principles of a Zippe-type gas centrifuge with U-238 represented in dark blue and U-235 represented in light blue</div></div></div>
<p>The <a href="/enwiki/wiki/Zippe_centrifuge" class="mw-redirect" title="Zippe centrifuge">Zippe centrifuge</a> is an improvement on the standard gas centrifuge, the primary difference being the use of heat. The bottom of the rotating cylinder is heated, producing convection currents that move the <sup>235</sup>U up the cylinder, where it can be collected by scoops. This improved centrifuge design is used commercially by <a href="/enwiki/wiki/Urenco_Group" title="Urenco Group">Urenco</a> to produce nuclear fuel and was used by <a href="/enwiki/wiki/Pakistan" title="Pakistan">Pakistan</a> in their nuclear weapons program.
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<h3><span class="mw-headline" id="Laser_techniques">Laser techniques</span><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/enwiki/w/index.php?title=Enriched_uranium&action=edit&section=9" title="Edit section: Laser techniques">edit</a><span class="mw-editsection-bracket">]</span></span></h3>
<p>Laser processes promise lower energy inputs, lower capital costs and lower tails assays, hence significant economic advantages. Several laser processes have been investigated or are under development. <i>Separation of isotopes by laser excitation</i> (<a href="/enwiki/wiki/SILEX" class="mw-redirect" title="SILEX">SILEX</a>) is well advanced and licensed for commercial operation in 2012.
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<h4><span id="Atomic_vapor_laser_isotope_separation_.28AVLIS.29"></span><span class="mw-headline" id="Atomic_vapor_laser_isotope_separation_(AVLIS)">Atomic vapor laser isotope separation (AVLIS)</span><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/enwiki/w/index.php?title=Enriched_uranium&action=edit&section=10" title="Edit section: Atomic vapor laser isotope separation (AVLIS)">edit</a><span class="mw-editsection-bracket">]</span></span></h4>
<p><i><a href="/enwiki/wiki/AVLIS" class="mw-redirect" title="AVLIS">Atomic vapor laser isotope separation</a></i> employs specially tuned lasers<sup id="cite_ref-9" class="reference"><a href="#cite_note-9">[9]</a></sup> to separate isotopes of uranium using selective ionization of <a href="/enwiki/wiki/Hyperfine_transitions" class="mw-redirect" title="Hyperfine transitions">hyperfine transitions</a>. The technique uses <a href="/enwiki/wiki/Laser" title="Laser">lasers</a> tuned to frequencies that ionize <sup>235</sup>U atoms and no others. The positively charged <sup>235</sup>U ions are then attracted to a negatively charged plate and collected.
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<h4><span id="Molecular_laser_isotope_separation_.28MLIS.29"></span><span class="mw-headline" id="Molecular_laser_isotope_separation_(MLIS)">Molecular laser isotope separation (MLIS)</span><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/enwiki/w/index.php?title=Enriched_uranium&action=edit&section=11" title="Edit section: Molecular laser isotope separation (MLIS)">edit</a><span class="mw-editsection-bracket">]</span></span></h4>
<p><i><a href="/enwiki/wiki/Molecular_laser_isotope_separation" title="Molecular laser isotope separation">Molecular laser isotope separation</a></i> uses an infrared laser directed at <a href="/enwiki/wiki/Uranium_hexafluoride" title="Uranium hexafluoride">UF<sub>6</sub></a>, exciting molecules that contain a <sup>235</sup>U atom. A second laser frees a <a href="/enwiki/wiki/Fluorine" title="Fluorine">fluorine</a> atom, leaving <a href="/enwiki/wiki/Uranium_pentafluoride" title="Uranium pentafluoride">uranium pentafluoride</a>, which then precipitates out of the gas.
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<h4><span id="Separation_of_isotopes_by_laser_excitation_.28SILEX.29"></span><span class="mw-headline" id="Separation_of_isotopes_by_laser_excitation_(SILEX)">Separation of isotopes by laser excitation (SILEX)</span><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/enwiki/w/index.php?title=Enriched_uranium&action=edit&section=12" title="Edit section: Separation of isotopes by laser excitation (SILEX)">edit</a><span class="mw-editsection-bracket">]</span></span></h4>
<p><i><a href="/enwiki/wiki/SILEX" class="mw-redirect" title="SILEX">Separation of isotopes by laser excitation</a></i> is an Australian development that also uses <a href="/enwiki/wiki/Uranium_hexafluoride" title="Uranium hexafluoride">UF<sub>6</sub></a>. After a protracted development process involving U.S. enrichment company <a href="/enwiki/wiki/USEC" class="mw-redirect" title="USEC">USEC</a> acquiring and then relinquishing commercialization rights to the technology, <a href="/enwiki/wiki/GE_Hitachi_Nuclear_Energy" title="GE Hitachi Nuclear Energy">GE Hitachi Nuclear Energy</a> (GEH) signed a commercialization agreement with <a href="/enwiki/w/index.php?title=Silex_Systems&action=edit&redlink=1" class="new" title="Silex Systems (page does not exist)">Silex Systems</a> in 2006.<sup id="cite_ref-10" class="reference"><a href="#cite_note-10">[10]</a></sup> GEH has since built a demonstration test loop and announced plans to build an initial commercial facility.<sup id="cite_ref-11" class="reference"><a href="#cite_note-11">[11]</a></sup> Details of the process are classified and restricted by intergovernmental agreements between United States, Australia, and the commercial entities. SILEX has been projected to be an order of magnitude more efficient than existing production techniques but again, the exact figure is classified.<sup id="cite_ref-Lodge_6-2" class="reference"><a href="#cite_note-Lodge-6">[6]</a></sup> In August, 2011 Global Laser Enrichment, a subsidiary of GEH, applied to the U.S. <a href="/enwiki/wiki/Nuclear_Regulatory_Commission" title="Nuclear Regulatory Commission">Nuclear Regulatory Commission</a> (NRC) for a permit to build a commercial plant.<sup id="cite_ref-12" class="reference"><a href="#cite_note-12">[12]</a></sup> In September 2012, the NRC issued a license for GEH to build and operate a commercial SILEX enrichment plant, although the company had not yet decided whether the project would be profitable enough to begin construction, and despite concerns that the technology could contribute to <a href="/enwiki/wiki/Nuclear_proliferation" title="Nuclear proliferation">nuclear proliferation</a>.<sup id="cite_ref-13" class="reference"><a href="#cite_note-13">[13]</a></sup>
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<h3><span class="mw-headline" id="Other_techniques">Other techniques</span><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/enwiki/w/index.php?title=Enriched_uranium&action=edit&section=13" title="Edit section: Other techniques">edit</a><span class="mw-editsection-bracket">]</span></span></h3>
<h4><span class="mw-headline" id="Aerodynamic_processes">Aerodynamic processes</span><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/enwiki/w/index.php?title=Enriched_uranium&action=edit&section=14" title="Edit section: Aerodynamic processes">edit</a><span class="mw-editsection-bracket">]</span></span></h4>
<div class="thumb tright"><div class="thumbinner" style="width:222px;"><a href="/enwiki/wiki/File:Aerodynamic_enrichment_nozzle.svg" class="image"><img alt="" src="/upwiki/wikipedia/commons/thumb/7/7d/Aerodynamic_enrichment_nozzle.svg/220px-Aerodynamic_enrichment_nozzle.svg.png" decoding="async" width="220" height="154" class="thumbimage" srcset="/upwiki/wikipedia/commons/thumb/7/7d/Aerodynamic_enrichment_nozzle.svg/330px-Aerodynamic_enrichment_nozzle.svg.png 1.5x, /upwiki/wikipedia/commons/thumb/7/7d/Aerodynamic_enrichment_nozzle.svg/440px-Aerodynamic_enrichment_nozzle.svg.png 2x" data-file-width="734" data-file-height="513" /></a> <div class="thumbcaption"><div class="magnify"><a href="/enwiki/wiki/File:Aerodynamic_enrichment_nozzle.svg" class="internal" title="Enlarge"></a></div>Schematic diagram of an aerodynamic nozzle. Many thousands of these small foils would be combined in an enrichment unit.</div></div></div>
<div class="thumb tright"><div class="thumbinner" style="width:222px;"><a href="/enwiki/wiki/File:LIGA-Doppelumlenksystem.jpg" class="image"><img alt="" src="/upwiki/wikipedia/commons/thumb/e/e8/LIGA-Doppelumlenksystem.jpg/220px-LIGA-Doppelumlenksystem.jpg" decoding="async" width="220" height="137" class="thumbimage" srcset="/upwiki/wikipedia/commons/thumb/e/e8/LIGA-Doppelumlenksystem.jpg/330px-LIGA-Doppelumlenksystem.jpg 1.5x, /upwiki/wikipedia/commons/thumb/e/e8/LIGA-Doppelumlenksystem.jpg/440px-LIGA-Doppelumlenksystem.jpg 2x" data-file-width="1186" data-file-height="738" /></a> <div class="thumbcaption"><div class="magnify"><a href="/enwiki/wiki/File:LIGA-Doppelumlenksystem.jpg" class="internal" title="Enlarge"></a></div>The X-ray based <a href="/enwiki/wiki/LIGA" title="LIGA">LIGA</a> manufacturing process was originally developed at the Forschungszentrum Karlsruhe, Germany, to produce nozzles for isotope enrichment.<sup id="cite_ref-Becker-1982_14-0" class="reference"><a href="#cite_note-Becker-1982-14">[14]</a></sup></div></div></div>
<p>Aerodynamic enrichment processes include the Becker jet nozzle techniques developed by E. W. Becker and associates using the <a href="/enwiki/wiki/LIGA" title="LIGA">LIGA</a> process and the <a href="/enwiki/wiki/Vortex_tube" title="Vortex tube">vortex tube</a> separation process. These <a href="/enwiki/wiki/Aerodynamic" class="mw-redirect" title="Aerodynamic">aerodynamic</a> separation processes depend upon diffusion driven by pressure gradients, as does the gas centrifuge. They in general have the disadvantage of requiring complex systems of cascading of individual separating elements to minimize energy consumption. In effect, aerodynamic processes can be considered as non-rotating centrifuges. Enhancement of the centrifugal forces is achieved by dilution of <a href="/enwiki/wiki/Uranium_hexafluoride" title="Uranium hexafluoride">UF<sub>6</sub></a> with <a href="/enwiki/wiki/Hydrogen" title="Hydrogen">hydrogen</a> or <a href="/enwiki/wiki/Helium" title="Helium">helium</a> as a carrier gas achieving a much higher flow velocity for the gas than could be obtained using pure uranium hexafluoride. The <a href="/enwiki/wiki/NECSA" class="mw-redirect" title="NECSA">Uranium Enrichment Corporation of South Africa</a> (UCOR) developed and deployed the continuous Helikon vortex separation cascade for high production rate low enrichment and the substantially different semi-batch Pelsakon low production rate high enrichment cascade both using a particular vortex tube separator design, and both embodied in industrial plant.<sup id="cite_ref-The_Pelsakon_Cascade_for_Uranium_Enrichment_15-0" class="reference"><a href="#cite_note-The_Pelsakon_Cascade_for_Uranium_Enrichment-15">[15]</a></sup> A demonstration plant was built in <a href="/enwiki/wiki/Brazil" title="Brazil">Brazil</a> by NUCLEI, a consortium led by <a href="/enwiki/w/index.php?title=Industrias_Nucleares_do_Brasil&action=edit&redlink=1" class="new" title="Industrias Nucleares do Brasil (page does not exist)">Industrias Nucleares do Brasil</a> that used the separation nozzle process. However all methods have high energy consumption and substantial requirements for removal of waste heat; none are currently still in use.
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<h4><span class="mw-headline" id="Electromagnetic_isotope_separation">Electromagnetic isotope separation</span><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/enwiki/w/index.php?title=Enriched_uranium&action=edit&section=15" title="Edit section: Electromagnetic isotope separation">edit</a><span class="mw-editsection-bracket">]</span></span></h4>
<div role="note" class="hatnote navigation-not-searchable">Main article: <a href="/enwiki/wiki/Calutron" title="Calutron">Calutron</a></div>
<div class="thumb tright"><div class="thumbinner" style="width:222px;"><a href="/enwiki/wiki/File:Electromagnetic_separation.svg" class="image"><img alt="" src="/upwiki/wikipedia/commons/thumb/0/05/Electromagnetic_separation.svg/220px-Electromagnetic_separation.svg.png" decoding="async" width="220" height="170" class="thumbimage" srcset="/upwiki/wikipedia/commons/thumb/0/05/Electromagnetic_separation.svg/330px-Electromagnetic_separation.svg.png 1.5x, /upwiki/wikipedia/commons/thumb/0/05/Electromagnetic_separation.svg/440px-Electromagnetic_separation.svg.png 2x" data-file-width="756" data-file-height="584" /></a> <div class="thumbcaption"><div class="magnify"><a href="/enwiki/wiki/File:Electromagnetic_separation.svg" class="internal" title="Enlarge"></a></div>Schematic diagram of uranium isotope separation in a <a href="/enwiki/wiki/Calutron" title="Calutron">calutron</a> shows how a strong magnetic field is used to redirect a stream of uranium ions to a target, resulting in a higher concentration of uranium-235 (represented here in dark blue) in the inner fringes of the stream.</div></div></div>
<p>In the <a href="/enwiki/wiki/Electromagnetic_isotope_separation" class="mw-redirect" title="Electromagnetic isotope separation">electromagnetic isotope separation</a> process (EMIS), metallic uranium is first vaporized, and then ionized to positively charged ions. The cations are then accelerated and subsequently deflected by magnetic fields onto their respective collection targets. A production-scale <a href="/enwiki/wiki/Mass_spectrometer" class="mw-redirect" title="Mass spectrometer">mass spectrometer</a> named the <a href="/enwiki/wiki/Calutron" title="Calutron">Calutron</a> was developed during World War II that provided some of the <sup>235</sup>U used for the <a href="/enwiki/wiki/Little_Boy" title="Little Boy">Little Boy</a> nuclear bomb, which was dropped over <a href="/enwiki/wiki/Hiroshima" title="Hiroshima">Hiroshima</a> in 1945. Properly the term 'Calutron' applies to a multistage device arranged in a large oval around a powerful electromagnet. Electromagnetic isotope separation has been largely abandoned in favour of more effective methods.
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<h4><span class="mw-headline" id="Chemical_methods">Chemical methods</span><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/enwiki/w/index.php?title=Enriched_uranium&action=edit&section=16" title="Edit section: Chemical methods">edit</a><span class="mw-editsection-bracket">]</span></span></h4>
<p>One chemical process has been demonstrated to pilot plant stage but not used for production. The French CHEMEX process exploited a very slight difference in the two isotopes' propensity to change <a href="/enwiki/wiki/Valence_(chemistry)" title="Valence (chemistry)">valency</a> in <a href="/enwiki/wiki/Redox" title="Redox">oxidation/reduction</a>, using immiscible aqueous and organic phases. An ion-exchange process was developed by the <a href="/enwiki/w/index.php?title=Asahi_Chemical_Company&action=edit&redlink=1" class="new" title="Asahi Chemical Company (page does not exist)">Asahi Chemical Company</a> in <a href="/enwiki/wiki/Japan" title="Japan">Japan</a> that applies similar chemistry but effects separation on a proprietary resin <a href="/enwiki/wiki/Ion-exchange" class="mw-redirect" title="Ion-exchange">ion-exchange</a> column.
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<h4><span class="mw-headline" id="Plasma_separation">Plasma separation</span><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/enwiki/w/index.php?title=Enriched_uranium&action=edit&section=17" title="Edit section: Plasma separation">edit</a><span class="mw-editsection-bracket">]</span></span></h4>
<p>Plasma separation process (PSP) describes a technique that makes use of <a href="/enwiki/wiki/Superconducting_magnet" title="Superconducting magnet">superconducting magnets</a> and <a href="/enwiki/wiki/Plasma_physics" class="mw-redirect" title="Plasma physics">plasma physics</a>. In this process, the principle of <a href="/enwiki/wiki/Ion_cyclotron_resonance" title="Ion cyclotron resonance">ion cyclotron resonance</a> is used to selectively energize the <sup>235</sup>U isotope in a <a href="/enwiki/wiki/Plasma_(physics)" title="Plasma (physics)">plasma</a> containing a mix of <a href="/enwiki/wiki/Ion" title="Ion">ions</a>. The French developed their own version of PSP, which they called RCI. Funding for RCI was drastically reduced in 1986, and the program was suspended around 1990, although RCI is still used for stable isotope separation.
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<h2><span class="mw-headline" id="Separative_work_unit">Separative work unit</span><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/enwiki/w/index.php?title=Enriched_uranium&action=edit&section=18" title="Edit section: Separative work unit">edit</a><span class="mw-editsection-bracket">]</span></span></h2>
<div role="note" class="hatnote navigation-not-searchable">Further information: <a href="/enwiki/wiki/Separative_work_units" title="Separative work units">Separative work units</a></div><p>"Separative work" – the amount of separation done by an enrichment process – is a function of the concentrations of the feedstock, the enriched output, and the depleted tailings; and is expressed in units that are so calculated as to be proportional to the total input (energy / machine operation time) and to the mass processed. Separative work is <i>not</i> energy. The same amount of separative work will require different amounts of energy depending on the efficiency of the separation technology. Separative work is measured in <i>Separative work units</i> SWU, kg SW, or kg UTA (from the German <i>Urantrennarbeit</i> – literally <i>uranium separation work</i>)
</p><ul><li>1 SWU = 1 kg SW = 1 kg UTA</li>
<li>1 kSWU = 1 tSW = 1 t UTA</li>
<li>1 MSWU = 1 ktSW = 1 kt UTA</li></ul>
<h2><span class="mw-headline" id="Cost_issues">Cost issues</span><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/enwiki/w/index.php?title=Enriched_uranium&action=edit&section=19" title="Edit section: Cost issues">edit</a><span class="mw-editsection-bracket">]</span></span></h2>
<p>In addition to the separative work units provided by an enrichment facility, the other important parameter to be considered is the mass of natural uranium (NU) that is needed to yield a desired mass of enriched uranium. As with the number of SWUs, the amount of feed material required will also depend on the level of enrichment desired and upon the amount of <sup>235</sup>U that ends up in the depleted uranium. However, unlike the number of SWUs required during enrichment, which increases with decreasing levels of <sup>235</sup>U in the depleted stream, the amount of NU needed will decrease with decreasing levels of <sup>235</sup>U that end up in the DU.
</p><p>For example, in the enrichment of LEU for use in a light water reactor it is typical for the enriched stream to contain 3.6% <sup>235</sup>U (as compared to 0.7% in NU) while the depleted stream contains 0.2% to 0.3% <sup>235</sup>U. In order to produce one kilogram of this LEU it would require approximately 8 kilograms of NU and 4.5 SWU if the DU stream was allowed to have 0.3% <sup>235</sup>U. On the other hand, if the depleted stream had only 0.2% <sup>235</sup>U, then it would require just 6.7 kilograms of NU, but nearly 5.7 SWU of enrichment. Because the amount of NU required and the number of SWUs required during enrichment change in opposite directions, if NU is cheap and enrichment services are more expensive, then the operators will typically choose to allow more <sup>235</sup>U to be left in the DU stream whereas if NU is more expensive and enrichment is less so, then they would choose the opposite.
</p>
<h2><span class="mw-headline" id="Downblending">Downblending</span><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/enwiki/w/index.php?title=Enriched_uranium&action=edit&section=20" title="Edit section: Downblending">edit</a><span class="mw-editsection-bracket">]</span></span></h2>
<p>The opposite of enriching is downblending; surplus HEU can be downblended to LEU to make it suitable for use in commercial nuclear fuel.
</p><p>The HEU feedstock can contain unwanted uranium isotopes: <a href="/enwiki/wiki/Uranium-234" title="Uranium-234"><sup>234</sup>U</a> is a minor isotope contained in natural uranium; during the enrichment process, its concentration increases but remains well below 1%. High concentrations of <a href="/enwiki/wiki/Uranium-236" title="Uranium-236"><sup>236</sup>U</a> are a byproduct from irradiation in a reactor and may be contained in the HEU, depending on its manufacturing history. HEU reprocessed from nuclear weapons material production reactors (with an <sup>235</sup>U assay of approx. 50%) may contain <sup>236</sup>U concentrations as high as 25%, resulting in concentrations of approximately 1.5% in the blended LEU product. <a href="/enwiki/wiki/Uranium-236" title="Uranium-236"><sup>236</sup>U</a> is a <a href="/enwiki/wiki/Neutron_poison" title="Neutron poison">neutron poison</a>; therefore the actual <sup>235</sup>U concentration in the LEU product must be raised accordingly to compensate for the presence of <sup>236</sup>U.
</p><p>The blendstock can be NU, or DU, however depending on feedstock quality, SEU at typically 1.5 wt% <sup>235</sup>U may used as a blendstock to dilute the unwanted byproducts that may be contained in the HEU feed. Concentrations of these isotopes in the LEU product in some cases could exceed <a href="/enwiki/wiki/ASTM" class="mw-redirect" title="ASTM">ASTM</a> specifications for nuclear fuel, if NU, or DU were used. So, the HEU downblending generally cannot contribute to the waste management problem posed by the existing large stockpiles of depleted uranium. At present, 95 percent of the world's stocks of depleted uranium remain in secure storage.<sup class="noprint Inline-Template Template-Fact" style="white-space:nowrap;">[<i><a href="/enwiki/wiki/Wikipedia:Citation_needed" title="Wikipedia:Citation needed"><span title="This claim needs references to reliable sources. (January 2020)">citation needed</span></a></i>]</sup>
</p><p>A major downblending undertaking called the <a href="/enwiki/wiki/Megatons_to_Megawatts_Program" title="Megatons to Megawatts Program">Megatons to Megawatts Program</a> converts ex-Soviet weapons-grade HEU to fuel for U.S. commercial power reactors. From 1995 through mid-2005, 250 tonnes of high-enriched uranium (enough for 10,000 warheads) was recycled into low-enriched-uranium. The goal is to recycle 500 tonnes by 2013. The decommissioning programme of Russian nuclear warheads accounted for about 13% of total world requirement for enriched uranium leading up to 2008.<sup id="cite_ref-Lodge_6-3" class="reference"><a href="#cite_note-Lodge-6">[6]</a></sup>
</p><p>The <a href="/enwiki/wiki/United_States_Enrichment_Corporation" title="United States Enrichment Corporation">United States Enrichment Corporation</a> has been involved in the disposition of a portion of the 174.3 tonnes of highly enriched uranium (HEU) that the U.S. government declared as surplus military material in 1996. Through the U.S. HEU Downblending Program, this HEU material, taken primarily from dismantled U.S. nuclear warheads, was recycled into low-enriched uranium (LEU) fuel, used by <a href="/enwiki/wiki/Nuclear_power_plants" class="mw-redirect" title="Nuclear power plants">nuclear power plants</a> to generate electricity.<sup id="cite_ref-16" class="reference"><a href="#cite_note-16">[16]</a></sup><sup id="cite_ref-17" class="reference"><a href="#cite_note-17">[17]</a></sup>
</p>
<h2><span class="mw-headline" id="Global_enrichment_facilities">Global enrichment facilities</span><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/enwiki/w/index.php?title=Enriched_uranium&action=edit&section=21" title="Edit section: Global enrichment facilities">edit</a><span class="mw-editsection-bracket">]</span></span></h2>
<p>The following countries are known to operate enrichment facilities: Argentina, Brazil, China, France, Germany, India, Iran, Japan, the Netherlands, North Korea, Pakistan, Russia, the United Kingdom, and the United States.<sup id="cite_ref-IEER-2004_18-0" class="reference"><a href="#cite_note-IEER-2004-18">[18]</a></sup><sup id="cite_ref-19" class="reference"><a href="#cite_note-19">[19]</a></sup> Belgium, Iran, Italy, and Spain hold an investment interest in the French <a href="/enwiki/wiki/Eurodif" title="Eurodif">Eurodif</a> enrichment plant, with <a href="/enwiki/wiki/Dominique_Lorentz#Eurodif_and_Iran's_nuclear_program" title="Dominique Lorentz">Iran's holding</a> entitling it to 10% of the enriched uranium output. Countries that had enrichment programs in the past include Libya and South Africa, although Libya's facility was never operational.<sup id="cite_ref-20" class="reference"><a href="#cite_note-20">[20]</a></sup> Australia has developed a <a href="/enwiki/wiki/Atomic_vapor_laser_isotope_separation" title="Atomic vapor laser isotope separation">laser enrichment</a> process known as SILEX, which it intends to pursue through financial investment in a U.S. commercial venture by General Electric.<sup id="cite_ref-21" class="reference"><a href="#cite_note-21">[21]</a></sup> It has also been claimed that Israel has a uranium enrichment program housed at the <a href="/enwiki/wiki/Negev_Nuclear_Research_Center" class="mw-redirect" title="Negev Nuclear Research Center">Negev Nuclear Research Center</a> site near <a href="/enwiki/wiki/Dimona" title="Dimona">Dimona</a>.<sup id="cite_ref-nwa-19971210_22-0" class="reference"><a href="#cite_note-nwa-19971210-22">[22]</a></sup>
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<h2><span class="mw-headline" id="Codename">Codename</span><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/enwiki/w/index.php?title=Enriched_uranium&action=edit&section=22" title="Edit section: Codename">edit</a><span class="mw-editsection-bracket">]</span></span></h2>
<p>During the <a href="/enwiki/wiki/Manhattan_Project" title="Manhattan Project">Manhattan Project</a> weapons-grade highly enriched uranium was given the codename <b>oralloy</b>,<sup class="noprint Inline-Template Template-Fact" style="white-space:nowrap;">[<i><a href="/enwiki/wiki/Wikipedia:Citation_needed" title="Wikipedia:Citation needed"><span title="This claim needs references to reliable sources. (January 2020)">citation needed</span></a></i>]</sup> a shortened version of <a href="/enwiki/wiki/Oak_Ridge,_Tennessee" title="Oak Ridge, Tennessee">Oak Ridge</a> <a href="/enwiki/wiki/Alloy" title="Alloy">alloy</a>,<sup class="noprint Inline-Template Template-Fact" style="white-space:nowrap;">[<i><a href="/enwiki/wiki/Wikipedia:Citation_needed" title="Wikipedia:Citation needed"><span title="This claim needs references to reliable sources. (January 2020)">citation needed</span></a></i>]</sup> after the location of the plants where the uranium was enriched. The term oralloy is still occasionally used to refer to enriched uranium.
</p>
<h2><span class="mw-headline" id="See_also">See also</span><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/enwiki/w/index.php?title=Enriched_uranium&action=edit&section=23" title="Edit section: See also">edit</a><span class="mw-editsection-bracket">]</span></span></h2>
<ul><li><a href="/enwiki/wiki/List_of_laser_articles" title="List of laser articles">List of laser articles</a></li>
<li><a href="/enwiki/wiki/MOX_fuel" title="MOX fuel">MOX fuel</a></li>
<li><a href="/enwiki/wiki/Nuclear_fuel_bank" title="Nuclear fuel bank">Nuclear fuel bank</a></li>
<li><a href="/enwiki/wiki/Orano" title="Orano">Orano</a></li>
<li><a href="/enwiki/wiki/Uranium_market" title="Uranium market">Uranium market</a></li>
<li><a href="/enwiki/wiki/Uranium_mining" title="Uranium mining">Uranium mining</a></li></ul>
<h2><span class="mw-headline" id="References">References</span><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/enwiki/w/index.php?title=Enriched_uranium&action=edit&section=24" title="Edit section: References">edit</a><span class="mw-editsection-bracket">]</span></span></h2>
<div class="reflist" style="list-style-type: decimal;">
<div class="mw-references-wrap mw-references-columns"><ol class="references">
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<li id="cite_note-2"><span class="mw-cite-backlink"><b><a href="#cite_ref-2">^</a></b></span> <span class="reference-text"><cite id="CITEREFOECD_Nuclear_Energy_Agency2003" class="citation book cs1">OECD Nuclear Energy Agency (2003). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=PvL7twdmK9sC&pg=PA25"><i>Nuclear Energy Today</i></a>. OECD Publishing. p. 25. <a href="/enwiki/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/enwiki/wiki/Special:BookSources/9789264103283" title="Special:BookSources/9789264103283"><bdi>9789264103283</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Nuclear+Energy+Today&rft.pages=25&rft.pub=OECD+Publishing&rft.date=2003&rft.isbn=9789264103283&rft.au=OECD+Nuclear+Energy+Agency&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3DPvL7twdmK9sC%26pg%3DPA25&rfr_id=info%3Asid%2Fen.wikipedia.org%3AEnriched+uranium" class="Z3988"></span><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r951705291"/></span>
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<li id="cite_note-3"><span class="mw-cite-backlink"><b><a href="#cite_ref-3">^</a></b></span> <span class="reference-text"><cite id="CITEREFThomas_B._Cochran_(Natural_Resources_Defense_Council)1997" class="citation web cs1">Thomas B. Cochran (<a href="/enwiki/wiki/Natural_Resources_Defense_Council" title="Natural Resources Defense Council">Natural Resources Defense Council</a>) (12 June 1997). <a rel="nofollow" class="external text" href="https://web.archive.org/web/20120722184311/http://docs.nrdc.org/nuclear/files/nuc_06129701a_185.pdf">"Safeguarding Nuclear Weapon-Usable Materials in Russia"</a> <span class="cs1-format">(PDF)</span>. Proceedings of international forum on illegal nuclear traffic. Archived from <a rel="nofollow" class="external text" href="http://docs.nrdc.org/nuclear/files/nuc_06129701a_185.pdf">the original</a> <span class="cs1-format">(PDF)</span> on 22 July 2012.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Safeguarding+Nuclear+Weapon-Usable+Materials+in+Russia&rft.pub=Proceedings+of+international+forum+on+illegal+nuclear+traffic&rft.date=1997-06-12&rft.au=Thomas+B.+Cochran+%28Natural+Resources+Defense+Council%29&rft_id=http%3A%2F%2Fdocs.nrdc.org%2Fnuclear%2Ffiles%2Fnuc_06129701a_185.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3AEnriched+uranium" class="Z3988"></span><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r951705291"/></span>
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<li id="cite_note-4"><span class="mw-cite-backlink"><b><a href="#cite_ref-4">^</a></b></span> <span class="reference-text"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="http://www.world-nuclear.org/info/Nuclear-Fuel-Cycle/Conversion-Enrichment-and-Fabrication/Uranium-Enrichment/#.UWrver-IRAs">"Uranium Enrichment"</a>. <i>world-nuclear.org</i>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=world-nuclear.org&rft.atitle=Uranium+Enrichment&rft_id=http%3A%2F%2Fwww.world-nuclear.org%2Finfo%2FNuclear-Fuel-Cycle%2FConversion-Enrichment-and-Fabrication%2FUranium-Enrichment%2F%23.UWrver-IRAs&rfr_id=info%3Asid%2Fen.wikipedia.org%3AEnriched+uranium" class="Z3988"></span><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r951705291"/></span>
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<li id="cite_note-5"><span class="mw-cite-backlink"><b><a href="#cite_ref-5">^</a></b></span> <span class="reference-text"><cite class="citation cs2"><a rel="nofollow" class="external text" href="https://fas.org/sgp/othergov/doe/lanl/pubs/00416663.pdf"><i>Economic Perspective for Uranium Enrichment</i></a> <span class="cs1-format">(PDF)</span>, <q>The throughput per centrifuge unit is very small compared to that of a diffusion unit so small, in fact, that it is not compensated by the higher enrichment per unit. To produce the same amount of reactor-grade fuel requires a considerably larger number (approximately 50,000 to 500,000] of centrifuge units than diffusion units. This disadvantage, however, is outweighed by <b>the considerably lower (by a factor of 20) energy consumption per SWU</b> for the gas centrifuge</q></cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Economic+Perspective+for+Uranium+Enrichment&rft_id=https%3A%2F%2Ffas.org%2Fsgp%2Fothergov%2Fdoe%2Flanl%2Fpubs%2F00416663.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3AEnriched+uranium" class="Z3988"></span><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r951705291"/></span>
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<li id="cite_note-Lodge-6"><span class="mw-cite-backlink">^ <a href="#cite_ref-Lodge_6-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-Lodge_6-1"><sup><i><b>b</b></i></sup></a> <a href="#cite_ref-Lodge_6-2"><sup><i><b>c</b></i></sup></a> <a href="#cite_ref-Lodge_6-3"><sup><i><b>d</b></i></sup></a></span> <span class="reference-text"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="http://www.asx.com.au/asxpdf/20080410/pdf/318j6y3ctrzwqf.pdf">"Lodge Partners Mid-Cap Conference 11 April 2008"</a> <span class="cs1-format">(PDF)</span>. Silex Ltd. 11 April 2008.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Lodge+Partners+Mid-Cap+Conference+11+April+2008&rft.pub=Silex+Ltd&rft.date=2008-04-11&rft_id=http%3A%2F%2Fwww.asx.com.au%2Fasxpdf%2F20080410%2Fpdf%2F318j6y3ctrzwqf.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3AEnriched+uranium" class="Z3988"></span><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r951705291"/></span>
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<li id="cite_note-7"><span class="mw-cite-backlink"><b><a href="#cite_ref-7">^</a></b></span> <span class="reference-text"><cite id="CITEREFRod_Adams2011" class="citation web cs1">Rod Adams (24 May 2011). <a rel="nofollow" class="external text" href="http://archive.wikiwix.com/cache/20130128020737/http://atomicinsights.com/2011/05/mcconnell-asks-doe-to-keep-using-60-year-old-enrichment-plant-to-save-jobs.html">"McConnell asks DOE to keep using 60 year old enrichment plant to save jobs"</a>. Atomic Insights. Archived from <a rel="nofollow" class="external text" href="http://atomicinsights.com/2011/05/mcconnell-asks-doe-to-keep-using-60-year-old-enrichment-plant-to-save-jobs.html">the original</a> on 28 January 2013<span class="reference-accessdate">. Retrieved <span class="nowrap">26 January</span> 2013</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=McConnell+asks+DOE+to+keep+using+60+year+old+enrichment+plant+to+save+jobs&rft.pub=Atomic+Insights&rft.date=2011-05-24&rft.au=Rod+Adams&rft_id=http%3A%2F%2Fatomicinsights.com%2F2011%2F05%2Fmcconnell-asks-doe-to-keep-using-60-year-old-enrichment-plant-to-save-jobs.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3AEnriched+uranium" class="Z3988"></span><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r951705291"/></span>
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<li id="cite_note-8"><span class="mw-cite-backlink"><b><a href="#cite_ref-8">^</a></b></span> <span class="reference-text"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="http://www.world-nuclear-news.org/ENF_Paducah_enrichment_plant_to_be_closed_2805132.html">"Paducah enrichment plant to be closed. <i>The 1950s facility is the last remaining gaseous diffusion uranium enrichment plant in the world.</i>"</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Paducah+enrichment+plant+to+be+closed.+The+1950s+facility+is+the+last+remaining+gaseous+diffusion+uranium+enrichment+plant+in+the+world.&rft_id=http%3A%2F%2Fwww.world-nuclear-news.org%2FENF_Paducah_enrichment_plant_to_be_closed_2805132.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3AEnriched+uranium" class="Z3988"></span><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r951705291"/></span>
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<li id="cite_note-9"><span class="mw-cite-backlink"><b><a href="#cite_ref-9">^</a></b></span> <span class="reference-text"><a href="/enwiki/wiki/F._J._Duarte" title="F. J. Duarte">F. J. Duarte</a> and L.W. Hillman (Eds.), <i>Dye Laser Principles</i> (Academic, New York, 1990) Chapter 9.</span>
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<li id="cite_note-10"><span class="mw-cite-backlink"><b><a href="#cite_ref-10">^</a></b></span> <span class="reference-text"><cite class="citation pressrelease cs1"><a rel="nofollow" class="external text" href="https://web.archive.org/web/20060614092643/http://www.ge-energy.com/about/press/en/2006_press/052206b.htm">"GE Signs Agreement With Silex Systems Of Australia To Develop Uranium Enrichment Technology"</a> (Press release). GE Energy. 22 May 2006. Archived from <a rel="nofollow" class="external text" href="http://www.ge-energy.com/about/press/en/2006_press/052206b.htm">the original</a> on 14 June 2006.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=GE+Signs+Agreement+With+Silex+Systems+Of+Australia+To+Develop+Uranium+Enrichment+Technology&rft.pub=GE+Energy&rft.date=2006-05-22&rft_id=http%3A%2F%2Fwww.ge-energy.com%2Fabout%2Fpress%2Fen%2F2006_press%2F052206b.htm&rfr_id=info%3Asid%2Fen.wikipedia.org%3AEnriched+uranium" class="Z3988"></span><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r951705291"/></span>
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<li id="cite_note-11"><span class="mw-cite-backlink"><b><a href="#cite_ref-11">^</a></b></span> <span class="reference-text"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="http://www.businesswire.com/portal/site/ge/index.jsp?ndmViewId=news_view&ndmConfigId=1004554&newsId=20080430006101&newsLang=en&vnsId=681">"GE Hitachi Nuclear Energy Selects Wilmington, N.C. as Site for Potential Commercial Uranium Enrichment Facility"</a>. Business Wire. 30 April 2008<span class="reference-accessdate">. Retrieved <span class="nowrap">30 September</span> 2012</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=GE+Hitachi+Nuclear+Energy+Selects+Wilmington%2C+N.C.+as+Site+for+Potential+Commercial+Uranium+Enrichment+Facility&rft.pub=Business+Wire&rft.date=2008-04-30&rft_id=http%3A%2F%2Fwww.businesswire.com%2Fportal%2Fsite%2Fge%2Findex.jsp%3FndmViewId%3Dnews_view%26ndmConfigId%3D1004554%26newsId%3D20080430006101%26newsLang%3Den%26vnsId%3D681&rfr_id=info%3Asid%2Fen.wikipedia.org%3AEnriched+uranium" class="Z3988"></span><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r951705291"/></span>
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<li id="cite_note-12"><span class="mw-cite-backlink"><b><a href="#cite_ref-12">^</a></b></span> <span class="reference-text"><cite id="CITEREFBroad2011" class="citation news cs1">Broad, William J. (20 August 2011). <a rel="nofollow" class="external text" href="https://www.nytimes.com/2011/08/21/science/earth/21laser.html">"Laser Advances in Nuclear Fuel Stir Terror Fear"</a>. <i><a href="/enwiki/wiki/The_New_York_Times" title="The New York Times">The New York Times</a></i><span class="reference-accessdate">. Retrieved <span class="nowrap">21 August</span> 2011</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=The+New+York+Times&rft.atitle=Laser+Advances+in+Nuclear+Fuel+Stir+Terror+Fear&rft.date=2011-08-20&rft.aulast=Broad&rft.aufirst=William+J.&rft_id=https%3A%2F%2Fwww.nytimes.com%2F2011%2F08%2F21%2Fscience%2Fearth%2F21laser.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3AEnriched+uranium" class="Z3988"></span><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r951705291"/></span>
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<li id="cite_note-13"><span class="mw-cite-backlink"><b><a href="#cite_ref-13">^</a></b></span> <span class="reference-text"><cite class="citation news cs1"><a rel="nofollow" class="external text" href="https://www.nytimes.com/2012/09/28/business/energy-environment/uranium-plant-using-laser-technology-wins-us-approval.html?ref=science">"Uranium Plant Using Laser Technology Wins U.S. Approval"</a>. <i>New York Times</i>. September 2012.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=New+York+Times&rft.atitle=Uranium+Plant+Using+Laser+Technology+Wins+U.S.+Approval&rft.date=2012-09&rft_id=https%3A%2F%2Fwww.nytimes.com%2F2012%2F09%2F28%2Fbusiness%2Fenergy-environment%2Furanium-plant-using-laser-technology-wins-us-approval.html%3Fref%3Dscience&rfr_id=info%3Asid%2Fen.wikipedia.org%3AEnriched+uranium" class="Z3988"></span><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r951705291"/></span>
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<li id="cite_note-Becker-1982-14"><span class="mw-cite-backlink"><b><a href="#cite_ref-Becker-1982_14-0">^</a></b></span> <span class="reference-text"><cite id="CITEREFBecker,_E._W.EhrfeldMünchmeyerBetz1982" class="citation journal cs1">Becker, E. W.; Ehrfeld, W.; Münchmeyer, D.; Betz, H.; Heuberger, A.; Pongratz, S.; Glashauser, W.; Michel, H. J.; Siemens, R. (1982). "Production of Separation-Nozzle Systems for Uranium Enrichment by a Combination of X-Ray Lithography and Galvanoplastics". <i>Naturwissenschaften</i>. <b>69</b> (11): 520–523. <a href="/enwiki/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/1982NW.....69..520B">1982NW.....69..520B</a>. <a href="/enwiki/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1007%2FBF00463495">10.1007/BF00463495</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Naturwissenschaften&rft.atitle=Production+of+Separation-Nozzle+Systems+for+Uranium+Enrichment+by+a+Combination+of+X-Ray+Lithography+and+Galvanoplastics&rft.volume=69&rft.issue=11&rft.pages=520-523&rft.date=1982&rft_id=info%3Adoi%2F10.1007%2FBF00463495&rft_id=info%3Abibcode%2F1982NW.....69..520B&rft.au=Becker%2C+E.+W.&rft.au=Ehrfeld%2C+W.&rft.au=M%C3%BCnchmeyer%2C+D.&rft.au=Betz%2C+H.&rft.au=Heuberger%2C+A.&rft.au=Pongratz%2C+S.&rft.au=Glashauser%2C+W.&rft.au=Michel%2C+H.+J.&rft.au=Siemens%2C+R.&rfr_id=info%3Asid%2Fen.wikipedia.org%3AEnriched+uranium" class="Z3988"></span><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r951705291"/></span>
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<li id="cite_note-The_Pelsakon_Cascade_for_Uranium_Enrichment-15"><span class="mw-cite-backlink"><b><a href="#cite_ref-The_Pelsakon_Cascade_for_Uranium_Enrichment_15-0">^</a></b></span> <span class="reference-text"><cite id="CITEREFSmithJackson_A_G_M2000" class="citation journal cs1">Smith, Michael; Jackson A G M (2000). "Dr". <i>South African Institution of Chemical Engineers – Conference 2000</i>: 280–289.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=South+African+Institution+of+Chemical+Engineers+%E2%80%93+Conference+2000&rft.atitle=Dr&rft.pages=280-289&rft.date=2000&rft.aulast=Smith&rft.aufirst=Michael&rft.au=Jackson+A+G+M&rfr_id=info%3Asid%2Fen.wikipedia.org%3AEnriched+uranium" class="Z3988"></span><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r951705291"/></span>
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<li id="cite_note-16"><span class="mw-cite-backlink"><b><a href="#cite_ref-16">^</a></b></span> <span class="reference-text"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://web.archive.org/web/20010406102039/http://www.usec.com/v2001_02/HTML/Megatons_DOEstatus.asp">"Status Report: USEC-DOE Megatons to Megawatts Program"</a>. USEC.com. 1 May 2000. Archived from <a rel="nofollow" class="external text" href="http://www.usec.com/v2001_02/HTML/Megatons_DOEstatus.asp">the original</a> on 6 April 2001.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Status+Report%3A+USEC-DOE+Megatons+to+Megawatts+Program&rft.pub=USEC.com&rft.date=2000-05-01&rft_id=http%3A%2F%2Fwww.usec.com%2Fv2001_02%2FHTML%2FMegatons_DOEstatus.asp&rfr_id=info%3Asid%2Fen.wikipedia.org%3AEnriched+uranium" class="Z3988"></span><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r951705291"/></span>
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<li id="cite_note-17"><span class="mw-cite-backlink"><b><a href="#cite_ref-17">^</a></b></span> <span class="reference-text"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://www.centrusenergy.com/who-we-are/history/megatons-to-megawatts/">"Megatons to Megawatts"</a>. <i>centrusenergy.com</i>. December 2013.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=centrusenergy.com&rft.atitle=Megatons+to+Megawatts&rft.date=2013-12&rft_id=https%3A%2F%2Fwww.centrusenergy.com%2Fwho-we-are%2Fhistory%2Fmegatons-to-megawatts%2F&rfr_id=info%3Asid%2Fen.wikipedia.org%3AEnriched+uranium" class="Z3988"></span><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r951705291"/></span>
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<li id="cite_note-IEER-2004-18"><span class="mw-cite-backlink"><b><a href="#cite_ref-IEER-2004_18-0">^</a></b></span> <span class="reference-text"><cite id="CITEREFArjun_MakhijaniLois_ChalmersBrice_Smith2004" class="citation book cs1">Arjun Makhijani; Lois Chalmers; Brice Smith (15 October 2004). <a rel="nofollow" class="external text" href="http://www.ieer.org/reports/uranium/enrichment.pdf"><i>Uranium enrichment</i></a> <span class="cs1-format">(PDF)</span>. Institute for Energy and Environmental Research<span class="reference-accessdate">. Retrieved <span class="nowrap">21 November</span> 2009</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Uranium+enrichment&rft.pub=Institute+for+Energy+and+Environmental+Research&rft.date=2004-10-15&rft.au=Arjun+Makhijani&rft.au=Lois+Chalmers&rft.au=Brice+Smith&rft_id=http%3A%2F%2Fwww.ieer.org%2Freports%2Furanium%2Fenrichment.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3AEnriched+uranium" class="Z3988"></span><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r951705291"/></span>
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<li id="cite_note-19"><span class="mw-cite-backlink"><b><a href="#cite_ref-19">^</a></b></span> <span class="reference-text"><cite class="citation report cs1"><a rel="nofollow" class="external text" href="http://www.aph.gov.au/binaries/house/committee/isr/uranium/report/fullreport.pdf">Australia's uranium - Greenhouse friendly fuel for an energy hungry world</a> <span class="cs1-format">(PDF)</span>. <i>Standing Committee on Industry and Resources</i> (Report). The Parliament of the Commonwealth of Australia. November 2006. p. 730<span class="reference-accessdate">. Retrieved <span class="nowrap">3 April</span> 2015</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=report&rft.btitle=Australia%27s+uranium+-+Greenhouse+friendly+fuel+for+an+energy+hungry+world&rft.pages=730&rft.pub=The+Parliament+of+the+Commonwealth+of+Australia&rft.date=2006-11&rft_id=http%3A%2F%2Fwww.aph.gov.au%2Fbinaries%2Fhouse%2Fcommittee%2Fisr%2Furanium%2Freport%2Ffullreport.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3AEnriched+uranium" class="Z3988"></span><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r951705291"/></span>
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<li id="cite_note-20"><span class="mw-cite-backlink"><b><a href="#cite_ref-20">^</a></b></span> <span class="reference-text"><cite id="CITEREFBBC2006" class="citation news cs1">BBC (1 September 2006). <a rel="nofollow" class="external text" href="http://news.bbc.co.uk/1/hi/world/middle_east/5278806.stm">"Q&A: Uranium enrichment"</a>. <i>BBC News</i><span class="reference-accessdate">. Retrieved <span class="nowrap">3 January</span> 2010</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=BBC+News&rft.atitle=Q%26A%3A+Uranium+enrichment&rft.date=2006-09-01&rft.au=BBC&rft_id=http%3A%2F%2Fnews.bbc.co.uk%2F1%2Fhi%2Fworld%2Fmiddle_east%2F5278806.stm&rfr_id=info%3Asid%2Fen.wikipedia.org%3AEnriched+uranium" class="Z3988"></span><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r951705291"/></span>
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<li id="cite_note-21"><span class="mw-cite-backlink"><b><a href="#cite_ref-21">^</a></b></span> <span class="reference-text"><cite class="citation news cs1"><a rel="nofollow" class="external text" href="http://www.smh.com.au/news/national/laser-enrichment-could-cut-cost-of-nuclear-power/2006/05/26/1148524888448.html">"Laser enrichment could cut cost of nuclear power"</a>. <i>The Sydney Morning Herald</i>. 26 May 2006.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=The+Sydney+Morning+Herald&rft.atitle=Laser+enrichment+could+cut+cost+of+nuclear+power&rft.date=2006-05-26&rft_id=http%3A%2F%2Fwww.smh.com.au%2Fnews%2Fnational%2Flaser-enrichment-could-cut-cost-of-nuclear-power%2F2006%2F05%2F26%2F1148524888448.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3AEnriched+uranium" class="Z3988"></span><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r951705291"/></span>
</li>
<li id="cite_note-nwa-19971210-22"><span class="mw-cite-backlink"><b><a href="#cite_ref-nwa-19971210_22-0">^</a></b></span> <span class="reference-text"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="http://nuclearweaponarchive.org/Israel/">"Israel's Nuclear Weapons Program"</a>. Nuclear Weapon Archive. 10 December 1997<span class="reference-accessdate">. Retrieved <span class="nowrap">7 October</span> 2007</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Israel%27s+Nuclear+Weapons+Program&rft.pub=Nuclear+Weapon+Archive&rft.date=1997-12-10&rft_id=http%3A%2F%2Fnuclearweaponarchive.org%2FIsrael%2F&rfr_id=info%3Asid%2Fen.wikipedia.org%3AEnriched+uranium" class="Z3988"></span><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r951705291"/></span>
</li>
</ol></div></div>
<h2><span class="mw-headline" id="External_links">External links</span><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/enwiki/w/index.php?title=Enriched_uranium&action=edit&section=25" title="Edit section: External links">edit</a><span class="mw-editsection-bracket">]</span></span></h2>
<table role="presentation" class="mbox-small plainlinks sistersitebox" style="background-color:#f9f9f9;border:1px solid #aaa;color:#000">
<tbody><tr>
<td class="mbox-image"><img alt="" src="/upwiki/wikipedia/commons/thumb/9/99/Wiktionary-logo-en-v2.svg/40px-Wiktionary-logo-en-v2.svg.png" decoding="async" width="40" height="40" class="noviewer" srcset="/upwiki/wikipedia/commons/thumb/9/99/Wiktionary-logo-en-v2.svg/60px-Wiktionary-logo-en-v2.svg.png 1.5x, /upwiki/wikipedia/commons/thumb/9/99/Wiktionary-logo-en-v2.svg/80px-Wiktionary-logo-en-v2.svg.png 2x" data-file-width="512" data-file-height="512" /></td>
<td class="mbox-text plainlist">Look up <i><b><a href="https://en.wiktionary.org/wiki/Special:Search/enriched_uranium" class="extiw" title="wiktionary:Special:Search/enriched uranium">enriched uranium</a></b></i> in Wiktionary, the free dictionary.</td></tr>
</tbody></table>
<ul><li><a rel="nofollow" class="external text" href="https://web.archive.org/web/20090531024234/http://alsos.wlu.edu/qsearch.aspx?browse=science%2FEnriching+Uranium">Annotated bibliography on enriched uranium from the Alsos Digital Library for Nuclear Issues</a></li>
<li><a rel="nofollow" class="external text" href="http://www.silex.com.au">Silex Systems Ltd</a></li>
<li><a rel="nofollow" class="external text" href="http://world-nuclear.org/info/inf28.html">Uranium Enrichment</a>, World Nuclear Association</li>
<li><a rel="nofollow" class="external text" href="https://fas.org/sgp/othergov/doe/heu/index.html">Overview and history of U.S. HEU production</a></li>
<li><a rel="nofollow" class="external text" href="https://web.archive.org/web/20070303234531/http://www.huliq.com/tags/uranium-enrichment">News Resource on Uranium Enrichment</a></li>
<li><a rel="nofollow" class="external text" href="http://www.chemcases.com/nuclear/nc-07.htm">Nuclear Chemistry-Uranium Enrichment</a></li>
<li><a rel="nofollow" class="external text" href="https://web.archive.org/web/20110613105504/http://www.neimagazine.com/story.asp?storyCode=2050947">A busy year for SWU (a 2008 review of the commercial enrichment marketplace)</a>, Nuclear Engineering International, 1 September 2008</li>
<li><a rel="nofollow" class="external text" href="https://web.archive.org/web/20110727073116/http://books.sipri.org/product_info?c_product_id=286"><i>Uranium Enrichment and Nuclear Weapon Proliferation</i>, by Allan S. Krass, Peter Boskma, Boelie Elzen and Wim A. Smit, 296 pp., published for SIPRI by Taylor and Francis Ltd, London, 1983</a></li>
<li><cite id="CITEREFPoliakoff2009" class="citation web cs1"><a href="/enwiki/wiki/Martyn_Poliakoff" title="Martyn Poliakoff">Poliakoff, Martyn</a> (2009). <a rel="nofollow" class="external text" href="http://www.periodicvideos.com/videos/feature_uranium_enrichment.htm">"How do you enrich Uranium?"</a>. <i><a href="/enwiki/wiki/The_Periodic_Table_of_Videos" class="mw-redirect" title="The Periodic Table of Videos">The Periodic Table of Videos</a></i>. <a href="/enwiki/wiki/University_of_Nottingham" title="University of Nottingham">University of Nottingham</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=The+Periodic+Table+of+Videos&rft.atitle=How+do+you+enrich+Uranium%3F&rft.date=2009&rft.aulast=Poliakoff&rft.aufirst=Martyn&rft_id=http%3A%2F%2Fwww.periodicvideos.com%2Fvideos%2Ffeature_uranium_enrichment.htm&rfr_id=info%3Asid%2Fen.wikipedia.org%3AEnriched+uranium" class="Z3988"></span><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r951705291"/></li>
<li><cite id="CITEREFGilinskyHoehn1969" class="citation web cs1">Gilinsky, V.; Hoehn, W. (December 1969). <a rel="nofollow" class="external text" href="https://web.archive.org/web/20160216062519/http://oai.dtic.mil/oai/oai?verb=getRecord&metadataPrefix=html&identifier=ADA613260">"The Military Significance of Small Uranium Enrichment Facilities Fed with Low-Enrichment Uranium (Redacted)"</a>. <i><a href="/enwiki/wiki/Defense_Technical_Information_Center" title="Defense Technical Information Center">Defense Technical Information Center</a></i>. <a href="/enwiki/wiki/RAND_Corporation" title="RAND Corporation">RAND Corporation</a>. Archived from <a rel="nofollow" class="external text" href="http://oai.dtic.mil/oai/oai?verb=getRecord&metadataPrefix=html&identifier=ADA613260">the original</a> on 16 February 2016<span class="reference-accessdate">. Retrieved <span class="nowrap">12 February</span> 2016</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=Defense+Technical+Information+Center&rft.atitle=The+Military+Significance+of+Small+Uranium+Enrichment+Facilities+Fed+with+Low-Enrichment+Uranium+%28Redacted%29&rft.date=1969-12&rft.aulast=Gilinsky&rft.aufirst=V.&rft.au=Hoehn%2C+W.&rft_id=http%3A%2F%2Foai.dtic.mil%2Foai%2Foai%3Fverb%3DgetRecord%26metadataPrefix%3Dhtml%26identifier%3DADA613260&rfr_id=info%3Asid%2Fen.wikipedia.org%3AEnriched+uranium" class="Z3988"></span><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r951705291"/></li></ul>
<div role="navigation" class="navbox" aria-labelledby="Nuclear_technology" style="padding:3px"><table class="nowraplinks hlist | above = * [[Outline of nuclear technology|Outline]] mw-collapsible autocollapse navbox-inner" style="border-spacing:0;background:transparent;color:inherit"><tbody><tr><th scope="col" class="navbox-title" colspan="2"><div class="plainlinks hlist navbar mini"><ul><li class="nv-view"><a href="/enwiki/wiki/Template:Nuclear_technology" title="Template:Nuclear technology"><abbr title="View this template" style=";;background:none transparent;border:none;-moz-box-shadow:none;-webkit-box-shadow:none;box-shadow:none; padding:0;">v</abbr></a></li><li class="nv-talk"><a href="/enwiki/wiki/Template_talk:Nuclear_technology" title="Template talk:Nuclear technology"><abbr title="Discuss this template" style=";;background:none transparent;border:none;-moz-box-shadow:none;-webkit-box-shadow:none;box-shadow:none; padding:0;">t</abbr></a></li><li class="nv-edit"><a class="external text" href="https://en.wikipedia.org/enwiki/w/index.php?title=Template:Nuclear_technology&action=edit"><abbr title="Edit this template" style=";;background:none transparent;border:none;-moz-box-shadow:none;-webkit-box-shadow:none;box-shadow:none; padding:0;">e</abbr></a></li></ul></div><div id="Nuclear_technology" style="font-size:114%;margin:0 4em"><a href="/enwiki/wiki/Nuclear_technology" title="Nuclear technology">Nuclear technology</a></div></th></tr><tr><td colspan="2" class="navbox-list navbox-odd" style="width:100%;padding:0px"><div style="padding:0em 0.25em"></div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><th scope="row" class="navbox-group" style="width:1%">Science</th><td class="navbox-list navbox-odd" style="text-align:left;border-left-width:2px;border-left-style:solid;width:100%;padding:0px"><div style="padding:0em 0.25em">
<ul><li><a href="/enwiki/wiki/Nuclear_chemistry" title="Nuclear chemistry">Chemistry</a></li>
<li><a href="/enwiki/wiki/Nuclear_engineering" title="Nuclear engineering">Engineering</a></li>
<li><a href="/enwiki/wiki/Nuclear_physics" title="Nuclear physics">Physics</a></li>
<li><a href="/enwiki/wiki/Atomic_nucleus" title="Atomic nucleus">Atomic nucleus</a></li>
<li><a href="/enwiki/wiki/Nuclear_fission" title="Nuclear fission">Fission</a></li>
<li><a href="/enwiki/wiki/Nuclear_fusion" title="Nuclear fusion">Fusion</a></li>
<li><a href="/enwiki/wiki/Radiation" title="Radiation">Radiation</a>
<ul><li><a href="/enwiki/wiki/Ionizing_radiation" title="Ionizing radiation">ionizing</a></li>
<li><a href="/enwiki/wiki/Bremsstrahlung" title="Bremsstrahlung">braking</a></li></ul></li></ul>
</div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/enwiki/wiki/Nuclear_fuel" title="Nuclear fuel">Fuel</a></th><td class="navbox-list navbox-even" style="text-align:left;border-left-width:2px;border-left-style:solid;width:100%;padding:0px"><div style="padding:0em 0.25em">
<ul><li><a href="/enwiki/wiki/Tritium" title="Tritium">Tritium</a></li>
<li><a href="/enwiki/wiki/Deuterium" title="Deuterium">Deuterium</a></li>
<li><a href="/enwiki/wiki/Helium-3" title="Helium-3">Helium-3</a></li>
<li><a href="/enwiki/wiki/Fertile_material" title="Fertile material">Fertile material</a></li>
<li><a href="/enwiki/wiki/Fissile_material" title="Fissile material">Fissile material</a></li>
<li><a href="/enwiki/wiki/Isotope_separation" title="Isotope separation">Isotope separation</a></li>
<li><a href="/enwiki/wiki/Nuclear_material" title="Nuclear material">Nuclear material</a>
<ul><li><a href="/enwiki/wiki/Uranium" title="Uranium">Uranium</a>
<ul><li><a class="mw-selflink selflink">enriched</a></li>
<li><a href="/enwiki/wiki/Depleted_uranium" title="Depleted uranium">depleted</a></li></ul></li>
<li><a href="/enwiki/wiki/Plutonium" title="Plutonium">Plutonium</a></li>
<li><a href="/enwiki/wiki/Thorium" title="Thorium">Thorium</a></li></ul></li></ul>
</div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/enwiki/wiki/Neutron" title="Neutron">Neutron</a></th><td class="navbox-list navbox-odd" style="text-align:left;border-left-width:2px;border-left-style:solid;width:100%;padding:0px"><div style="padding:0em 0.25em">
<ul><li><a href="/enwiki/wiki/Neutron_activation" title="Neutron activation">Activation</a></li>
<li><a href="/enwiki/wiki/Neutron_capture" title="Neutron capture">Capture</a></li>
<li><a href="/enwiki/wiki/Neutron_poison" title="Neutron poison">Poison</a></li>
<li><a href="/enwiki/wiki/Neutron_cross_section" title="Neutron cross section">Cross section</a></li>
<li><a href="/enwiki/wiki/Neutron_generator" title="Neutron generator">Generator</a></li>
<li><a href="/enwiki/wiki/Neutron_radiation" title="Neutron radiation">Radiation</a></li>
<li><a href="/enwiki/wiki/Neutron_reflector" title="Neutron reflector">Reflector</a></li>
<li><a href="/enwiki/wiki/Neutron_temperature" title="Neutron temperature">Temperature</a></li>
<li><a href="/enwiki/wiki/Thermal_neutron" class="mw-redirect" title="Thermal neutron">Thermal</a></li>
<li><a href="/enwiki/wiki/Fast_neutron" class="mw-redirect" title="Fast neutron">Fast</a></li>
<li><a href="/enwiki/wiki/Fusion_neutron" class="mw-redirect" title="Fusion neutron">Fusion</a></li></ul>
</div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/enwiki/wiki/Nuclear_power" title="Nuclear power">Power</a></th><td class="navbox-list navbox-even" style="text-align:left;border-left-width:2px;border-left-style:solid;width:100%;padding:0px"><div style="padding:0em 0.25em">
<ul><li><a href="/enwiki/wiki/Nuclear_power_by_country" title="Nuclear power by country">by country</a></li>
<li><a href="/enwiki/wiki/Nuclear_power_plant" title="Nuclear power plant">Power plant</a></li>
<li><a href="/enwiki/wiki/Economics_of_nuclear_power_plants" title="Economics of nuclear power plants">Economics</a></li>
<li><a href="/enwiki/wiki/Multi-mission_radioisotope_thermoelectric_generator" title="Multi-mission radioisotope thermoelectric generator">Multi-mission radioisotope thermoelectric generator</a></li>
<li><a href="/enwiki/wiki/Nuclear_and_radiation_accidents_and_incidents" title="Nuclear and radiation accidents and incidents">Accidents and incidents</a></li>
<li><a href="/enwiki/wiki/Nuclear_energy_policy" title="Nuclear energy policy">Policy</a></li>
<li><a href="/enwiki/wiki/Fusion_power" title="Fusion power">Fusion</a></li>
<li><a href="/enwiki/wiki/Radioisotope_thermoelectric_generator" title="Radioisotope thermoelectric generator">Radioisotope thermoelectric (RTG)</a></li>
<li><a href="/enwiki/wiki/Nuclear_propulsion" title="Nuclear propulsion">Propulsion</a>
<ul><li><a href="/enwiki/wiki/Nuclear_thermal_rocket" title="Nuclear thermal rocket">rocket</a></li></ul></li>
<li><a href="/enwiki/wiki/Nuclear_safety_and_security" title="Nuclear safety and security">Safety and security</a></li></ul>
</div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/enwiki/wiki/Nuclear_medicine" title="Nuclear medicine">Medicine</a></th><td class="navbox-list navbox-odd" style="text-align:left;border-left-width:2px;border-left-style:solid;width:100%;padding:0px;background:none;"><div style="padding:0em 0.25em"></div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><th scope="row" class="navbox-group" style="width:1%;width:4.0em;font-weight:normal;"><a href="/enwiki/wiki/Medical_imaging" title="Medical imaging">Imaging</a></th><td class="navbox-list navbox-odd" style="text-align:left;border-left-width:2px;border-left-style:solid;width:100%;padding:0px;width:auto;"><div style="padding:0em 0.25em">
<ul><li><a href="/enwiki/wiki/RadBall" title="RadBall">RadBall</a></li>
<li><a href="/enwiki/wiki/Scintigraphy" title="Scintigraphy">Scintigraphy</a></li>
<li><a href="/enwiki/wiki/Single-photon_emission_computed_tomography" title="Single-photon emission computed tomography">Single-photon emission (SPECT)</a></li>
<li><a href="/enwiki/wiki/Positron_emission_tomography" title="Positron emission tomography">Positron-emission tomography (PET)</a></li></ul>
</div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%;width:4.0em;font-weight:normal;">Therapy</th><td class="navbox-list navbox-even" style="text-align:left;border-left-width:2px;border-left-style:solid;width:100%;padding:0px;width:auto;;background:none;"><div style="padding:0em 0.25em">
<ul><li><a href="/enwiki/wiki/Fast_neutron_therapy" title="Fast neutron therapy">Fast-neutron</a></li>
<li><a href="/enwiki/wiki/Neutron_capture_therapy_of_cancer" title="Neutron capture therapy of cancer">Neutron capture therapy of cancer</a></li>
<li><a href="/enwiki/wiki/Targeted_alpha-particle_therapy" title="Targeted alpha-particle therapy">Targeted alpha-particle</a></li>
<li><a href="/enwiki/wiki/Proton_therapy" title="Proton therapy">Proton-beam</a></li>
<li><a href="/enwiki/wiki/Tomotherapy" title="Tomotherapy">Tomotherapy</a></li>
<li><a href="/enwiki/wiki/Brachytherapy" title="Brachytherapy">Brachytherapy</a></li>
<li><a href="/enwiki/wiki/Radiation_therapy" title="Radiation therapy">Radiation therapy</a></li>
<li><a href="/enwiki/wiki/Radiosurgery" title="Radiosurgery">Radiosurgery</a></li>
<li><a href="/enwiki/wiki/Radiopharmacology" title="Radiopharmacology">Radiopharmacology</a></li></ul>
</div></td></tr></tbody></table><div></div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/enwiki/wiki/Nuclear_weapon" title="Nuclear weapon">Weapons</a></th><td class="navbox-list navbox-odd" style="text-align:left;border-left-width:2px;border-left-style:solid;width:100%;padding:0px;background:none;"><div style="padding:0em 0.25em"></div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><th scope="row" class="navbox-group" style="width:1%;width:4.0em;font-weight:normal;">Topics</th><td class="navbox-list navbox-odd" style="text-align:left;border-left-width:2px;border-left-style:solid;width:100%;padding:0px;width:auto;"><div style="padding:0em 0.25em">
<ul><li><a href="/enwiki/wiki/Nuclear_arms_race" title="Nuclear arms race">Arms race</a></li>
<li><a href="/enwiki/wiki/Nuclear_weapons_delivery" title="Nuclear weapons delivery">Delivery</a></li>
<li><a href="/enwiki/wiki/Nuclear_weapon_design" title="Nuclear weapon design">Design</a></li>
<li><a href="/enwiki/wiki/Nuclear_disarmament" title="Nuclear disarmament">Disarmament</a></li>
<li><a href="/enwiki/wiki/Nuclear_ethics" title="Nuclear ethics">Ethics</a></li>
<li><a href="/enwiki/wiki/Nuclear_explosion" title="Nuclear explosion">Explosion</a>
<ul><li><a href="/enwiki/wiki/Effects_of_nuclear_explosions" title="Effects of nuclear explosions">effects</a></li></ul></li>
<li><a href="/enwiki/wiki/History_of_nuclear_weapons" title="History of nuclear weapons">History</a></li>
<li><a href="/enwiki/wiki/Nuclear_proliferation" title="Nuclear proliferation">Proliferation</a></li>
<li><a href="/enwiki/wiki/Nuclear_weapons_testing" title="Nuclear weapons testing">Testing</a>
<ul><li><a href="/enwiki/wiki/High-altitude_nuclear_explosion" title="High-altitude nuclear explosion">high-altitude</a></li>
<li><a href="/enwiki/wiki/Underground_nuclear_weapons_testing" title="Underground nuclear weapons testing">underground</a></li></ul></li>
<li><a href="/enwiki/wiki/Nuclear_warfare" title="Nuclear warfare">Warfare</a></li>
<li><a href="/enwiki/wiki/Nuclear_weapon_yield" title="Nuclear weapon yield">Yield</a>
<ul><li><a href="/enwiki/wiki/TNT_equivalent" title="TNT equivalent">TNTe</a></li></ul></li></ul>
</div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%;width:4.0em;font-weight:normal;">Lists</th><td class="navbox-list navbox-even" style="text-align:left;border-left-width:2px;border-left-style:solid;width:100%;padding:0px;width:auto;"><div style="padding:0em 0.25em">
<ul><li><a href="/enwiki/wiki/List_of_estimated_death_tolls_from_nuclear_attacks_on_cities" class="mw-redirect" title="List of estimated death tolls from nuclear attacks on cities">Estimated death tolls from attacks</a></li>
<li><a href="/enwiki/wiki/List_of_states_with_nuclear_weapons" title="List of states with nuclear weapons">States with nuclear weapons</a></li>
<li><a href="/enwiki/wiki/Historical_nuclear_weapons_stockpiles_and_nuclear_tests_by_country" title="Historical nuclear weapons stockpiles and nuclear tests by country">Historical stockpiles and tests</a>
<ul><li><a href="/enwiki/wiki/List_of_nuclear_weapons_tests" title="List of nuclear weapons tests">Tests</a></li>
<li><a href="/enwiki/wiki/List_of_nuclear_weapons_tests_of_the_United_States" class="mw-redirect" title="List of nuclear weapons tests of the United States">Tests in the United States</a></li></ul></li>
<li><a href="/enwiki/wiki/List_of_weapons_of_mass_destruction_treaties" title="List of weapons of mass destruction treaties">WMD treaties</a></li>
<li><a href="/enwiki/wiki/Nuclear-weapon-free_zone" title="Nuclear-weapon-free zone">Weapon-free zones</a></li>
<li><a href="/enwiki/wiki/List_of_nuclear_weapons" title="List of nuclear weapons">Weapons</a></li></ul>
</div></td></tr></tbody></table><div></div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/enwiki/wiki/Radioactive_waste" title="Radioactive waste">Waste</a></th><td class="navbox-list navbox-odd" style="text-align:left;border-left-width:2px;border-left-style:solid;width:100%;padding:0px;background:none;"><div style="padding:0em 0.25em"></div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><th scope="row" class="navbox-group" style="width:1%;width:4.0em;font-weight:normal;">Products</th><td class="navbox-list navbox-odd" style="text-align:left;border-left-width:2px;border-left-style:solid;width:100%;padding:0px;width:auto;"><div style="padding:0em 0.25em">
<ul><li><a href="/enwiki/wiki/Actinide" title="Actinide">Actinide</a>
<ul><li><a href="/enwiki/wiki/Reprocessed_uranium" title="Reprocessed uranium">Reprocessed uranium</a></li>
<li><a href="/enwiki/wiki/Reactor-grade_plutonium" title="Reactor-grade plutonium">Reactor-grade plutonium</a></li>
<li><a href="/enwiki/wiki/Minor_actinide" title="Minor actinide">Minor actinide</a></li></ul></li>
<li><a href="/enwiki/wiki/Activation_product" title="Activation product">Activation</a></li>
<li><a href="/enwiki/wiki/Nuclear_fission_product" title="Nuclear fission product">Fission</a>
<ul><li><a href="/enwiki/wiki/Long-lived_fission_product" title="Long-lived fission product">LLFP</a></li></ul></li>
<li><a href="/enwiki/wiki/Actinide_chemistry" title="Actinide chemistry">Actinide chemistry</a></li></ul>
</div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%;width:4.0em;font-weight:normal;">Disposal</th><td class="navbox-list navbox-even" style="text-align:left;border-left-width:2px;border-left-style:solid;width:100%;padding:0px;width:auto;"><div style="padding:0em 0.25em">
<ul><li><a href="/enwiki/wiki/Nuclear_fuel_cycle" title="Nuclear fuel cycle">Fuel cycle</a></li>
<li><a href="/enwiki/wiki/High-level_waste" title="High-level waste">High-level (HLW)</a></li>
<li><a href="/enwiki/wiki/Low-level_waste" title="Low-level waste">Low-level (LLW)</a></li>
<li><a href="/enwiki/wiki/Deep_geological_repository" title="Deep geological repository">Repository</a></li>
<li><a href="/enwiki/wiki/Nuclear_reprocessing" title="Nuclear reprocessing">Reprocessing</a></li>
<li><a href="/enwiki/wiki/Spent_nuclear_fuel" title="Spent nuclear fuel">Spent fuel</a>
<ul><li><a href="/enwiki/wiki/Spent_fuel_pool" title="Spent fuel pool">pool</a></li>
<li><a href="/enwiki/wiki/Dry_cask_storage" title="Dry cask storage">cask</a></li></ul></li>
<li><a href="/enwiki/wiki/Nuclear_transmutation" title="Nuclear transmutation">Transmutation</a></li></ul>
</div></td></tr></tbody></table><div></div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Debate</th><td class="navbox-list navbox-odd" style="text-align:left;border-left-width:2px;border-left-style:solid;width:100%;padding:0px"><div style="padding:0em 0.25em">
<ul><li><a href="/enwiki/wiki/Nuclear_power_debate" title="Nuclear power debate">Nuclear power</a></li>
<li><a href="/enwiki/wiki/Nuclear_weapons_debate" title="Nuclear weapons debate">Nuclear weapons</a></li>
<li><a href="/enwiki/wiki/Blue_Ribbon_Commission_on_America%27s_Nuclear_Future" title="Blue Ribbon Commission on America's Nuclear Future">Blue Ribbon Commission on America's Nuclear Future</a></li>
<li><a href="/enwiki/wiki/Anti-nuclear_movement" title="Anti-nuclear movement">Anti-nuclear movement</a></li>
<li><a href="/enwiki/wiki/Uranium_mining_debate" title="Uranium mining debate">Uranium mining</a></li>
<li><a href="/enwiki/wiki/Nuclear_power_phase-out" title="Nuclear power phase-out">Nuclear power phase-out</a></li></ul>
</div></td></tr></tbody></table><div></div></td></tr><tr><td colspan="2" class="navbox-list navbox-odd" style="width:100%;padding:0px"><div style="padding:0em 0.25em"></div><table class="nowraplinks mw-collapsible expanded navbox-subgroup" style="border-spacing:0"><tbody><tr><th scope="col" class="navbox-title" colspan="2"><div id="Nuclear_reactors" style="font-size:114%;margin:0 4em"><a href="/enwiki/wiki/Nuclear_reactor" title="Nuclear reactor">Nuclear reactors</a></div></th></tr><tr><td colspan="2" class="navbox-list navbox-odd" style="width:100%;padding:0px"><div style="padding:0em 0.25em"></div><table class="nowraplinks mw-collapsible autocollapse navbox-subgroup" style="border-spacing:0"><tbody><tr><th scope="col" class="navbox-title" colspan="2"><div id="Fission" style="font-size:114%;margin:0 4em"><span style="font-size:90%;"><a href="/enwiki/wiki/Nuclear_reactor#Fission" title="Nuclear reactor">Fission</a></span></div></th></tr><tr><td class="navbox-abovebelow" colspan="2"><div id="Moderator"><div style="float: left;"><b><a href="/enwiki/wiki/Neutron_moderator" title="Neutron moderator">Moderator</a></b></div></div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/enwiki/wiki/Light-water_reactor" title="Light-water reactor">Light water</a></th><td class="navbox-list navbox-odd hlist" style="text-align:left;border-left-width:2px;border-left-style:solid;width:100%;padding:0px;background:none;"><div style="padding:0em 0.25em">
<ul><li><a href="/enwiki/wiki/Aqueous_homogeneous_reactor" title="Aqueous homogeneous reactor">Aqueous homogeneous</a></li>
<li><a href="/enwiki/wiki/Boiling_water_reactor" title="Boiling water reactor">Boiling</a>
<ul><li><a href="/enwiki/wiki/GE_BWR" title="GE BWR">BWR</a></li>
<li><a href="/enwiki/wiki/Advanced_boiling_water_reactor" title="Advanced boiling water reactor">ABWR</a></li>
<li><a href="/enwiki/wiki/Economic_Simplified_Boiling_Water_Reactor" title="Economic Simplified Boiling Water Reactor">ESBWR</a></li>
<li><a href="/enwiki/wiki/Kerena_boiling_water_reactor" class="mw-redirect" title="Kerena boiling water reactor">Kerena</a></li></ul></li>
<li><a href="/enwiki/wiki/Pressurized_water_reactor" title="Pressurized water reactor">Pressurized</a>
<ul><li><a href="/enwiki/wiki/AP1000" title="AP1000">AP1000</a></li>
<li><a href="/enwiki/wiki/APR-1400" title="APR-1400">APR-1400</a></li>
<li><a href="/enwiki/wiki/APR%2B" class="mw-redirect" title="APR+">APR+</a></li>
<li><a href="/enwiki/wiki/APWR" class="mw-redirect" title="APWR">APWR</a></li>
<li><a href="/enwiki/wiki/ATMEA1" class="mw-redirect" title="ATMEA1">ATMEA1</a></li>
<li><a href="/enwiki/wiki/CAP1400" class="mw-redirect" title="CAP1400">CAP1400</a></li>
<li><a href="/enwiki/wiki/CPR-1000" title="CPR-1000">CPR-1000</a></li>
<li><a href="/enwiki/wiki/EPR_(nuclear_reactor)" title="EPR (nuclear reactor)">EPR</a></li>
<li><a href="/enwiki/wiki/Hualong_One" title="Hualong One">HPR-1000</a>
<ul><li><a href="/enwiki/wiki/ACPR1000" class="mw-redirect" title="ACPR1000">ACPR1000</a></li>
<li><a href="/enwiki/wiki/ACP1000" class="mw-redirect" title="ACP1000">ACP1000</a></li></ul></li>
<li><a href="/enwiki/wiki/VVER" title="VVER">VVER</a></li>
<li>many others</li></ul></li>
<li><a href="/enwiki/wiki/Supercritical_water_reactor" title="Supercritical water reactor">Supercritical (SCWR)</a></li>
<li><a href="/enwiki/wiki/Natural_nuclear_fission_reactor" title="Natural nuclear fission reactor">Natural fission</a></li></ul>
</div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/enwiki/wiki/Heavy-water_reactor" class="mw-redirect" title="Heavy-water reactor">Heavy water</a></th><td class="navbox-list navbox-odd hlist" style="text-align:left;border-left-width:2px;border-left-style:solid;width:100%;padding:0px;background:none;;background:whitesmoke;"><div style="padding:0em 0.25em"></div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><th scope="row" class="navbox-group" style="width:1%;font-weight:normal;"><a href="/enwiki/wiki/Deuterium_oxide" class="mw-redirect" title="Deuterium oxide">D<sub>2</sub>O</a></th><td class="navbox-list navbox-even" style="text-align:left;border-left-width:2px;border-left-style:solid;width:100%;padding:0px"><div style="padding:0em 0.25em">
<ul><li><a href="/enwiki/wiki/Pressurized_heavy-water_reactor" title="Pressurized heavy-water reactor">Pressurized</a>
<ul><li><a href="/enwiki/wiki/CANDU_reactor" title="CANDU reactor">CANDU</a>
<ul><li>CANDU 6</li>
<li>CANDU 9</li>
<li>EC6</li>
<li>AFCR</li>
<li><a href="/enwiki/wiki/ACR-1000" class="mw-redirect" title="ACR-1000">ACR-1000</a></li></ul></li>
<li><a href="/enwiki/wiki/Advanced_heavy-water_reactor" title="Advanced heavy-water reactor">AHWR</a></li>
<li><a href="/enwiki/wiki/Carolinas%E2%80%93Virginia_Tube_Reactor" title="Carolinas–Virginia Tube Reactor">CVTR</a></li>
<li><a href="/enwiki/wiki/Nuclear_power_in_India" title="Nuclear power in India">IPHWR-X</a></li>
<li><a href="/enwiki/wiki/Nuclear_energy_in_Argentina" title="Nuclear energy in Argentina">PHWR KWU</a></li>
<li><a href="/enwiki/w/index.php?title=MZFR&action=edit&redlink=1" class="new" title="MZFR (page does not exist)">MZFR</a></li>
<li><a href="/enwiki/wiki/%C3%85gestaverket" class="mw-redirect" title="Ågestaverket">R3</a></li>
<li><a href="/enwiki/wiki/R4_nuclear_reactor" title="R4 nuclear reactor">R4 Marviken</a></li></ul></li></ul>
</div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%;font-weight:normal;"><a href="/enwiki/wiki/H2O" class="mw-redirect" title="H2O">H<sub>2</sub>O</a></th><td class="navbox-list navbox-odd" style="text-align:left;border-left-width:2px;border-left-style:solid;width:100%;padding:0px"><div style="padding:0em 0.25em">
<ul><li><a href="/enwiki/w/index.php?title=HWLWR&action=edit&redlink=1" class="new" title="HWLWR (page does not exist)">HWLWR</a>
<ul><li><a href="/enwiki/wiki/Fugen_Nuclear_Power_Plant" title="Fugen Nuclear Power Plant">ATR</a></li>
<li><a href="/enwiki/wiki/Gentilly_Nuclear_Generating_Station#Gentilly-1" title="Gentilly Nuclear Generating Station">HW BLWR 250</a></li></ul></li>
<li><a href="/enwiki/wiki/Steam-generating_heavy_water_reactor" class="mw-redirect" title="Steam-generating heavy water reactor">Steam-generating (SGHWR)</a></li></ul>
</div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%;font-weight:normal;"><a href="/enwiki/wiki/Organic_matter" title="Organic matter">Organic</a></th><td class="navbox-list navbox-even" style="text-align:left;border-left-width:2px;border-left-style:solid;width:100%;padding:0px"><div style="padding:0em 0.25em">
<ul><li><a href="/enwiki/wiki/WR-1" title="WR-1">WR-1</a></li></ul>
</div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%;font-weight:normal;"><a href="/enwiki/wiki/Carbon_dioxide" title="Carbon dioxide">CO<sub>2</sub></a></th><td class="navbox-list navbox-odd" style="text-align:left;border-left-width:2px;border-left-style:solid;width:100%;padding:0px"><div style="padding:0em 0.25em">
<ul><li><a href="/enwiki/w/index.php?title=HWGCR&action=edit&redlink=1" class="new" title="HWGCR (page does not exist)">HWGCR</a>
<ul><li><a href="/enwiki/wiki/Brennilis_Nuclear_Power_Plant" title="Brennilis Nuclear Power Plant">EL-4</a></li>
<li><a href="/enwiki/w/index.php?title=Kernkraftwerk_Niederaichbach&action=edit&redlink=1" class="new" title="Kernkraftwerk Niederaichbach (page does not exist)">KKN</a></li>
<li><a href="/enwiki/wiki/KS_150" title="KS 150">KS 150</a></li>
<li><a href="/enwiki/wiki/Lucens_reactor" title="Lucens reactor">Lucens</a></li></ul></li></ul>
</div></td></tr></tbody></table><div></div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><div style="padding:0.1em 0;line-height:1.2em;"><a href="/enwiki/wiki/Graphite-moderated_reactor" title="Graphite-moderated reactor">Graphite</a> <br /><span style="font-size:90%;"><style data-mw-deduplicate="TemplateStyles:r886047488">.mw-parser-output .nobold{font-weight:normal}</style><span class="nobold">by <a href="/enwiki/wiki/Nuclear_reactor_coolant" title="Nuclear reactor coolant">coolant</a></span></span></div></th><td class="navbox-list navbox-odd hlist" style="text-align:left;border-left-width:2px;border-left-style:solid;width:100%;padding:0px;background:none;"><div style="padding:0em 0.25em"></div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><th scope="row" class="navbox-group" style="width:1%;font-weight:normal;">Water</th><td class="navbox-list navbox-odd" style="text-align:left;border-left-width:2px;border-left-style:solid;width:100%;padding:0px"><div style="padding:0em 0.25em"></div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><th id="H2O" scope="row" class="navbox-group" style="width:2.5em;font-weight:normal;"><a href="/enwiki/wiki/H2O" class="mw-redirect" title="H2O">H<sub>2</sub>O</a></th><td class="navbox-list navbox-even" style="text-align:left;border-left-width:2px;border-left-style:solid;padding:0px"><div style="padding:0em 0.25em">
<ul><li><a href="/enwiki/wiki/Obninsk_Nuclear_Power_Plant" title="Obninsk Nuclear Power Plant">AM-1</a></li>
<li><a href="/enwiki/wiki/Beloyarsk_Nuclear_Power_Station#Early_reactors" title="Beloyarsk Nuclear Power Station">AMB-X</a></li>
<li><a href="/enwiki/wiki/EGP-6" title="EGP-6">EGP-6</a></li>
<li><a href="/enwiki/wiki/RBMK" title="RBMK">RBMK</a></li></ul>
</div></td></tr></tbody></table><div></div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%;font-weight:normal;"><a href="/enwiki/wiki/Gas-cooled_reactor" title="Gas-cooled reactor">Gas</a></th><td class="navbox-list navbox-odd" style="text-align:left;border-left-width:2px;border-left-style:solid;width:100%;padding:0px"><div style="padding:0em 0.25em"></div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><th scope="row" class="navbox-group" style="width:2.5em;font-weight:normal;"><a href="/enwiki/wiki/Carbon_dioxide" title="Carbon dioxide">CO<sub>2</sub></a></th><td class="navbox-list navbox-odd" style="text-align:left;border-left-width:2px;border-left-style:solid;padding:0px"><div style="padding:0em 0.25em">
<ul><li><a href="/enwiki/wiki/UNGG_reactor" title="UNGG reactor"><i>Uranium Naturel Graphite Gaz</i> (UNGG)</a></li>
<li><a href="/enwiki/wiki/Magnox" title="Magnox">Magnox</a></li>
<li><a href="/enwiki/wiki/Advanced_Gas-cooled_Reactor" title="Advanced Gas-cooled Reactor">Advanced gas-cooled (AGR)</a></li></ul>
</div></td></tr><tr><th scope="row" class="navbox-group" style="width:2.5em;font-weight:normal;"><a href="/enwiki/wiki/Helium" title="Helium">He</a></th><td class="navbox-list navbox-even" style="text-align:left;border-left-width:2px;border-left-style:solid;padding:0px"><div style="padding:0em 0.25em">
<ul><li><a href="/enwiki/wiki/Gas_turbine_modular_helium_reactor" title="Gas turbine modular helium reactor">GTMHR</a>
<ul><li><a href="/enwiki/w/index.php?title=MHR-T&action=edit&redlink=1" class="new" title="MHR-T (page does not exist)">MHR-T</a></li></ul></li>
<li><a href="/enwiki/wiki/UHTREX" title="UHTREX">UHTREX</a></li>
<li><a href="/enwiki/wiki/Very-high-temperature_reactor" title="Very-high-temperature reactor">VHTR (HTGR)</a>
<ul><li><a href="/enwiki/wiki/Pebble-bed_reactor" title="Pebble-bed reactor">PBR (PBMR)</a>
<ul><li><a href="/enwiki/wiki/AVR_reactor" title="AVR reactor">AVR</a></li>
<li><a href="/enwiki/wiki/HTR-10" title="HTR-10">HTR-10</a></li>
<li><a href="/enwiki/wiki/HTR-PM" title="HTR-PM">HTR-PM</a></li>
<li><a href="/enwiki/wiki/THTR-300" title="THTR-300">THTR-300</a></li></ul></li>
<li><a href="/enwiki/w/index.php?title=Prismatic_block_reactor&action=edit&redlink=1" class="new" title="Prismatic block reactor (page does not exist)">PMR</a></li></ul></li></ul>
</div></td></tr></tbody></table><div></div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%;font-weight:normal;"><a href="/enwiki/wiki/Molten_salt_reactor" title="Molten salt reactor">Molten-salt</a></th><td class="navbox-list navbox-odd" style="text-align:left;border-left-width:2px;border-left-style:solid;width:100%;padding:0px"><div style="padding:0em 0.25em"></div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><th id="Fluorides" scope="row" class="navbox-group" style="width:2.5em;font-weight:normal;"><a href="/enwiki/wiki/FLiBe" title="FLiBe">Fluorides</a></th><td class="navbox-list navbox-odd" style="text-align:left;border-left-width:2px;border-left-style:solid;padding:0px"><div style="padding:0em 0.25em">
<ul><li><a href="/enwiki/wiki/Fuji_Molten_Salt_Reactor" title="Fuji Molten Salt Reactor">Fuji MSR</a></li>
<li><a href="/enwiki/wiki/Liquid_fluoride_thorium_reactor" title="Liquid fluoride thorium reactor">Liquid-fluoride thorium reactor (LFTR)</a></li>
<li><a href="/enwiki/wiki/Molten-Salt_Reactor_Experiment" title="Molten-Salt Reactor Experiment">Molten-Salt Reactor Experiment (MSRE)</a></li>
<li><a href="/enwiki/wiki/Integral_Molten_Salt_Reactor" title="Integral Molten Salt Reactor">Integral Molten Salt Reactor (IMSR)</a></li>
<li><a href="/enwiki/wiki/TMSR-500" title="TMSR-500">TMSR-500</a></li></ul>
</div></td></tr></tbody></table><div></div></td></tr></tbody></table><div></div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><div style="padding:0.1em 0;line-height:1.2em;">None<br /><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886047488"/><span class="nobold">(<a href="/enwiki/wiki/Fast-neutron_reactor" title="Fast-neutron reactor">fast-neutron</a>)</span></div></th><td class="navbox-list navbox-odd hlist" style="text-align:left;border-left-width:2px;border-left-style:solid;width:100%;padding:0px;background:none;"><div style="padding:0em 0.25em"></div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><td colspan="2" class="navbox-list navbox-even" style="width:100%;padding:0px"><div style="padding:0em 0.25em">
<ul><li><a href="/enwiki/wiki/Fast_breeder_reactor" class="mw-redirect" title="Fast breeder reactor">Breeder (FBR)</a></li>
<li><a href="/enwiki/wiki/Integral_fast_reactor" title="Integral fast reactor">Integral (IFR)</a></li>
<li><a href="/enwiki/wiki/Liquid_metal_cooled_reactor" title="Liquid metal cooled reactor">Liquid-metal-cooled (LMFR)</a></li>
<li><a href="/enwiki/wiki/Small,_sealed,_transportable,_autonomous_reactor" title="Small, sealed, transportable, autonomous reactor">Small sealed transportable autonomous (SSTAR)</a></li>
<li><a href="/enwiki/wiki/Traveling_wave_reactor" title="Traveling wave reactor">Traveling-wave (TWR)</a></li>
<li><a href="/enwiki/wiki/Energy_Multiplier_Module" title="Energy Multiplier Module">Energy Multiplier Module (EM2)</a></li>
<li><a href="/enwiki/wiki/Reduced_moderation_water_reactor" title="Reduced moderation water reactor">Reduced-moderation (RMWR)</a></li>
<li><a href="/enwiki/wiki/Fast_Breeder_Test_Reactor" title="Fast Breeder Test Reactor">Fast Breeder Test Reactor (FBTR)</a></li>
<li><a href="/enwiki/wiki/Dual_fluid_reactor" title="Dual fluid reactor">Dual fluid reactor (DFR)</a></li></ul>
</div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%;font-weight:normal;"><a href="/enwiki/wiki/Generation_IV_reactor#Fast_reactors" title="Generation IV reactor">Generation IV</a></th><td class="navbox-list navbox-odd" style="text-align:left;border-left-width:2px;border-left-style:solid;width:100%;padding:0px"><div style="padding:0em 0.25em">
<ul><li><a href="/enwiki/wiki/Sodium-cooled_fast_reactor" title="Sodium-cooled fast reactor">Sodium (SFR)</a>
<ul><li><a href="/enwiki/wiki/BN-350_reactor" title="BN-350 reactor">BN-350</a></li>
<li><a href="/enwiki/wiki/BN-600_reactor" title="BN-600 reactor">BN-600</a></li>
<li><a href="/enwiki/wiki/BN-800_reactor" title="BN-800 reactor">BN-800</a></li>
<li><a href="/enwiki/wiki/BN-1200_reactor" title="BN-1200 reactor">BN-1200</a></li>
<li><a href="/enwiki/wiki/CFR-600" title="CFR-600">CFR-600</a></li>
<li><a href="/enwiki/wiki/Ph%C3%A9nix" title="Phénix">Phénix</a></li>
<li><a href="/enwiki/wiki/Superph%C3%A9nix" title="Superphénix">Superphénix</a></li>
<li><a href="/enwiki/wiki/Prototype_Fast_Breeder_Reactor" title="Prototype Fast Breeder Reactor">PFBR</a></li>
<li><a href="/enwiki/wiki/China_Experimental_Fast_Reactor" title="China Experimental Fast Reactor">CEFR</a></li>
<li><a href="/enwiki/wiki/Dounreay#Prototype_Fast_Reactor_(PFR)" title="Dounreay">PFR</a></li>
<li><a href="/enwiki/wiki/PRISM_(reactor)" title="PRISM (reactor)">PRISM</a></li></ul></li>
<li><a href="/enwiki/wiki/Lead-cooled_fast_reactor" title="Lead-cooled fast reactor">Lead</a></li>
<li><a href="/enwiki/wiki/Gas-cooled_fast_reactor" title="Gas-cooled fast reactor">Helium gas (GFR)</a></li>
<li><a href="/enwiki/wiki/Stable_salt_reactor" title="Stable salt reactor">Stable Salt Reactor (SSR)</a></li></ul>
</div></td></tr></tbody></table><div></div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Others</th><td class="navbox-list navbox-even hlist" style="text-align:left;border-left-width:2px;border-left-style:solid;width:100%;padding:0px;background:none;"><div style="padding:0em 0.25em">
<ul><li><a href="/enwiki/wiki/Organic_nuclear_reactor" title="Organic nuclear reactor">Organic nuclear reactor</a>
<ul><li><a href="/enwiki/w/index.php?title=Arbus-reactor&action=edit&redlink=1" class="new" title="Arbus-reactor (page does not exist)">Arbus</a></li>
<li><a href="/enwiki/wiki/Piqua_Nuclear_Generating_Station" title="Piqua Nuclear Generating Station">Piqua</a></li></ul></li>
<li><a href="/enwiki/wiki/Aircraft_Nuclear_Propulsion" title="Aircraft Nuclear Propulsion">Aircraft Reactor Experiment</a></li></ul>
</div></td></tr></tbody></table><div>
</div><table class="nowraplinks mw-collapsible autocollapse navbox-subgroup" style="border-spacing:0"><tbody><tr><th scope="col" class="navbox-title" colspan="2"><div id="Fusion" style="font-size:114%;margin:0 4em"><span style="font-size:90%;"><a href="/enwiki/wiki/Nuclear_reactor#Fusion_reactors" title="Nuclear reactor">Fusion</a></span></div></th></tr><tr><td class="navbox-abovebelow" colspan="2"><div id="by_confinement">by <a href="/enwiki/wiki/Thermonuclear_fusion#Confinement" title="Thermonuclear fusion">confinement</a></div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/enwiki/wiki/Magnetic_confinement_fusion" title="Magnetic confinement fusion">Magnetic</a></th><td class="navbox-list navbox-odd hlist" style="text-align:left;border-left-width:2px;border-left-style:solid;width:100%;padding:0px"><div style="padding:0em 0.25em">
<ul><li><a href="/enwiki/wiki/Field-reversed_configuration" title="Field-reversed configuration">Field-reversed configuration</a></li>
<li><a href="/enwiki/wiki/Levitated_dipole" title="Levitated dipole">Levitated dipole</a></li>
<li><a href="/enwiki/wiki/Reversed_field_pinch" title="Reversed field pinch">Reversed field pinch</a></li>
<li><a href="/enwiki/wiki/Spheromak" title="Spheromak">Spheromak</a></li>
<li><a href="/enwiki/wiki/Stellarator" title="Stellarator">Stellarator</a></li>
<li><a href="/enwiki/wiki/Tokamak" title="Tokamak">Tokamak</a></li></ul>
</div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/enwiki/wiki/Inertial_confinement_fusion" title="Inertial confinement fusion">Inertial</a></th><td class="navbox-list navbox-even hlist" style="text-align:left;border-left-width:2px;border-left-style:solid;width:100%;padding:0px"><div style="padding:0em 0.25em">
<ul><li><a href="/enwiki/wiki/Bubble_fusion" title="Bubble fusion">Bubble <span style="font-size:85%;">(acoustic)</span></a></li>
<li><a href="/enwiki/wiki/Fusor" title="Fusor">Fusor</a>
<ul><li><a href="/enwiki/wiki/Inertial_electrostatic_confinement" title="Inertial electrostatic confinement">electrostatic</a></li></ul></li>
<li><a href="/enwiki/wiki/Inertial_confinement_fusion" title="Inertial confinement fusion">Laser-driven</a></li>
<li><a href="/enwiki/wiki/Magnetized_target_fusion" title="Magnetized target fusion">Magnetized-target</a></li>
<li><a href="/enwiki/wiki/Z-pinch" title="Z-pinch">Z-pinch</a></li></ul>
</div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Other</th><td class="navbox-list navbox-odd hlist" style="text-align:left;border-left-width:2px;border-left-style:solid;width:100%;padding:0px"><div style="padding:0em 0.25em">
<ul><li><a href="/enwiki/wiki/Dense_plasma_focus" title="Dense plasma focus">Dense plasma focus</a></li>
<li><a href="/enwiki/wiki/Migma" title="Migma">Migma</a></li>
<li><a href="/enwiki/wiki/Muon-catalyzed_fusion" title="Muon-catalyzed fusion">Muon-catalyzed</a></li>
<li><a href="/enwiki/wiki/Polywell" title="Polywell">Polywell</a></li>
<li><a href="/enwiki/wiki/Pyroelectric_fusion" title="Pyroelectric fusion">Pyroelectric</a></li></ul>
</div></td></tr></tbody></table><div></div></td></tr></tbody></table><div></div></td></tr><tr><td class="navbox-abovebelow" colspan="2"><div>
<ul><li><img alt="Category" src="/upwiki/wikipedia/en/thumb/4/48/Folder_Hexagonal_Icon.svg/16px-Folder_Hexagonal_Icon.svg.png" decoding="async" title="Category" width="16" height="14" srcset="/upwiki/wikipedia/en/thumb/4/48/Folder_Hexagonal_Icon.svg/24px-Folder_Hexagonal_Icon.svg.png 1.5x, /upwiki/wikipedia/en/thumb/4/48/Folder_Hexagonal_Icon.svg/32px-Folder_Hexagonal_Icon.svg.png 2x" data-file-width="36" data-file-height="31" /> <b><a href="/enwiki/wiki/Category:Nuclear_technology" title="Category:Nuclear technology">Category</a></b></li>
<li><img alt="Commons page" src="/upwiki/wikipedia/en/thumb/4/4a/Commons-logo.svg/12px-Commons-logo.svg.png" decoding="async" title="Commons page" width="12" height="16" srcset="/upwiki/wikipedia/en/thumb/4/4a/Commons-logo.svg/18px-Commons-logo.svg.png 1.5x, /upwiki/wikipedia/en/thumb/4/4a/Commons-logo.svg/24px-Commons-logo.svg.png 2x" data-file-width="1024" data-file-height="1376" /> <b><a href="https://commons.wikimedia.org/wiki/Category:Nuclear_technology" class="extiw" title="commons:Category:Nuclear technology">Commons</a></b></li>
<li><img alt="Portal" src="/upwiki/wikipedia/en/thumb/f/fd/Portal-puzzle.svg/16px-Portal-puzzle.svg.png" decoding="async" title="Portal" width="16" height="14" srcset="/upwiki/wikipedia/en/thumb/f/fd/Portal-puzzle.svg/24px-Portal-puzzle.svg.png 1.5x, /upwiki/wikipedia/en/thumb/f/fd/Portal-puzzle.svg/32px-Portal-puzzle.svg.png 2x" data-file-width="32" data-file-height="28" /> <b><a href="/enwiki/wiki/Portal:Nuclear_technology" title="Portal:Nuclear technology">Portal</a></b></li></ul>
</div></td></tr></tbody></table></div>
' |
Whether or not the change was made through a Tor exit node (tor_exit_node ) | false |
Unix timestamp of change (timestamp ) | 1594937368 |