Editing Enriched uranium (section)

===Diffusion techniques===

====Gaseous diffusion====
{{Main|Gaseous diffusion}}
[[File:Gaseous Diffusion (44021367082) (cropped).jpg|thumb|Gaseous diffusion uses semi-permeable membranes to separate enriched uranium]]

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 |archive-url=https://ghostarchive.org/archive/20221009/http://www.asx.com.au/asxpdf/20080410/pdf/318j6y3ctrzwqf.pdf |archive-date=2022-10-09 |url-status=live | title=Lodge Partners Mid-Cap Conference 11&nbsp;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 |last=Adams |first=Rod |date=24 May 2011 |title=McConnell asks DOE to keep using 60-year-old enrichment plant to save jobs |url=http://atomicinsights.com/2011/05/mcconnell-asks-doe-to-keep-using-60-year-old-enrichment-plant-to-save-jobs.html |url-status=dead |archive-url=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 |archive-date=28 January 2013 |access-date=26 January 2013 |publisher=Atomic Insights}}</ref> In 2013, the [[Paducah Gaseous Diffusion Plant|Paducah]] facility in the U.S. ceased operating; it was the last commercial <sup>235</sup>U gaseous diffusion plant in the world.<ref>{{Cite web|url=https://www.world-nuclear-news.org/ENF_Paducah_enrichment_plant_to_be_closed_2805132.html|title=Paducah enrichment plant to be closed|website=World Nuclear News}}</ref>

====Thermal diffusion====
Thermal diffusion uses the transfer of heat across a thin liquid or gas to accomplish isotope separation.<ref name="Lei Science Direct"/>  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, explained later in this article. It was abandoned in favor of gaseous diffusion.