Editing Uranium (section)

===Fission research===
[[File:UraniumCubesLarge.jpg|thumb|Cuboids of uranium produced during the Manhattan Project]]
A team led by [[Enrico Fermi]] in 1934 found that bombarding uranium with neutrons produces [[beta decay|beta rays]] ([[electron]]s or [[positron]]s from the elements produced; see [[beta particle]]).{{sfn|Seaborg|1968|p=773}} The fission products were at first mistaken for new elements with atomic numbers 93 and 94, which the Dean of the [[Sapienza University of Rome]], [[Orso Mario Corbino]], named [[ausenium and hesperium]], respectively.<ref>{{cite web
 |url          = https://www.nobelprize.org/nobel_prizes/physics/laureates/1938/fermi-lecture.pdf
 |last         = Fermi
 |first        = Enrico
 |date         = 12 December 1938
 |title        = Artificial radioactivity produced by neutron bombardment: Nobel Lecture
 |publisher    = Royal Swedish Academy of Sciences
 |access-date  = 14 June 2017
 |archive-url  = https://web.archive.org/web/20180809111423/https://www.nobelprize.org/nobel_prizes/physics/laureates/1938/fermi-lecture.pdf
 |archive-date = 9 August 2018
 |url-status     = dead
}}</ref><ref>{{cite journal |author=De Gregorio, A. |title=A Historical Note About How the Property was Discovered that Hydrogenated Substances Increase the Radioactivity Induced by Neutrons |date=2003 |pages=41–47 |volume=19 |journal=Nuovo Saggiatore |arxiv=physics/0309046}}</ref><ref>{{cite web |author=Nigro, M. |title=Hahn, Meitner e la teoria della fissione |url=http://www.brera.unimi.it/SISFA/atti/2003/312-321NigroBari.pdf |date=2004 |access-date=5 May 2009 |archive-date=25 March 2009 |archive-url=https://web.archive.org/web/20090325120427/http://www.brera.unimi.it/SISFA/atti/2003/312-321NigroBari.pdf |url-status=dead}}</ref><ref>{{cite web| author=van der Krogt, Peter |url=http://elements.vanderkrogt.net/element.php?sym=Pu |title=Elementymology & Elements Multidict |access-date=5 May 2009}}</ref> The experiments leading to the discovery of uranium's ability to fission (break apart) into lighter elements and release [[binding energy]] were conducted by [[Otto Hahn]] and [[Fritz Strassmann]]{{sfn|Seaborg|1968|p=773}} in Hahn's laboratory in Berlin. [[Lise Meitner]] and her nephew, physicist [[Otto Robert Frisch]], published the physical explanation in February 1939 and named the process "[[nuclear fission]]".<ref>{{cite journal
| title = Disintegration of Uranium by Neutrons: a New Type of Nuclear Reaction
| author1 = [[Lise Meitner|Meitner, L.]]
| author2 = [[Otto Frisch|Frisch, O.]]
| journal = Nature
| volume = 143
| date = 1939
| pages = 239–240
| doi = 10.1038/224466a0
| url = http://www.atomicarchive.com/Docs/Begin/Nature_Meitner.shtml |bibcode = 1969Natur.224..466M
| issue=5218| s2cid = 4188874
}}</ref> Soon after, Fermi hypothesized that fission of uranium might release enough neutrons to sustain a fission reaction. Confirmation of this hypothesis came in 1939, and later work found that on average about 2.5 neutrons are released by each fission of uranium-235.{{sfn|Seaborg|1968|p=773}} Fermi urged [[Alfred O. C. Nier]] to separate uranium isotopes for determination of the fissile component, and on 29 February 1940, Nier used an instrument he built at the [[University of Minnesota]] to separate the world's first [[uranium-235]] sample in the Tate Laboratory. Using [[Pupin Hall|Columbia University]]'s [[cyclotron]], [[John R. Dunning|John Dunning]] confirmed the sample to be the isolated fissile material on 1 March.<ref>{{cite web |title=Alfred O. C. Nier |url=https://www.aps.org/programs/outreach/history/historicsites/nier.cfm |website=www.aps.org |access-date=2016-12-04 |archive-date=19 July 2018 |archive-url=https://web.archive.org/web/20180719113725/https://www.aps.org/programs/outreach/history/historicsites/nier.cfm |url-status=dead }}</ref> Further work found that the far more common uranium-238 isotope can be [[Nuclear transmutation|transmuted]] into plutonium, which, like uranium-235, is also fissile by thermal neutrons. These discoveries led numerous countries to begin working on the development of nuclear weapons and [[nuclear power]]. Despite fission having been discovered in Germany, the ''[[Uranverein]]'' ("uranium club") Germany's wartime project to research nuclear power and/or weapons was hampered by limited resources, infighting, the exile or non-involvement of several prominent scientists in the field and several crucial mistakes such as failing to account for impurities in available graphite samples which made it appear less suitable as a [[neutron moderator]] than it is in reality. Germany's attempts to build a [[natural uranium]] / [[heavy water]] reactor had not come close to reaching criticality by the time the Americans reached [[Haigerloch]], the site of the last German wartime reactor experiment.<ref>{{cite web|author=Manfred Popp |url=https://www.spektrum.de/news/hitlers-atombombe-warum-es-sie-nicht-gab/1423529 |title=Wissenschaftsgeschichte: Hitlers Atombombe – warum es sie nicht gab – Spektrum der Wissenschaft |publisher=Spektrum.de |date=2016-09-21 |access-date=2022-02-25}}</ref>

On 2 December 1942, as part of the [[Manhattan Project]], another team led by Enrico Fermi was able to initiate the first artificial self-sustained [[nuclear chain reaction]], [[Chicago Pile-1]]. An initial plan using enriched uranium-235 was abandoned as it was as yet unavailable in sufficient quantities.<ref>{{cite web |url=http://large.stanford.edu/courses/2013/ph241/masters1/ |title=Chicago Pile One|website=large.stanford.edu|access-date=2016-12-04}}</ref> Working in a lab below the stands of [[Stagg Field]] at the [[University of Chicago]], the team created the conditions needed for such a reaction by piling together 360 tonnes of [[graphite]], 53 tonnes of [[uranium oxide]], and 5.5 tonnes of uranium metal, most of which was supplied by [[Westinghouse Lamp Plant]] in a makeshift production process.{{sfn|Seaborg|1968|p=773}}<ref>{{cite journal |last=Walsh |first=John |title=A Manhattan Project Postscript |journal=Science |date=19 June 1981 |volume=212 |pages=1369–1371 |bibcode=1981Sci...212.1369W |pmid=17746246 |url=http://pbadupws.nrc.gov/docs/ML0533/ML053340429.pdf |access-date=23 March 2013 |publisher=AAAS |doi=10.1126/science.212.4501.1369 |issue=4501}}</ref>