Editing Lithium (section)

=== Nuclear ===
Lithium-6 is valued as a source material for [[tritium]] production and as a [[neutron absorber]] in [[nuclear fusion]]. Natural lithium contains about 7.5% lithium-6 from which large amounts of lithium-6 have been produced by [[isotope separation]] for use in [[nuclear weapon]]s.<ref>{{cite book |pages=59–60 |url={{google books |plainurl=y |id=0oa1vikB3KwC |page=60}} |title=Nuclear Wastelands: A Global Guide to Nuclear Weapons Production and Its Health and Environmental Effects |author=Makhijani, Arjun |author2=Yih, Katherine |name-list-style=amp |publisher=MIT Press |date=2000 |isbn=978-0-262-63204-1 |url-status=live |archive-url=https://web.archive.org/web/20160613234841/https://books.google.com/books?id=0oa1vikB3KwC&pg=PA60 |archive-date=13 June 2016}}</ref> Lithium-7 gained interest for use in [[nuclear reactor]] [[coolant]]s.<ref>{{cite book |url={{google books |plainurl=y |id=iRI7Cx2D4e4C |page=278}} |page=278 |title=Nuclear wastes: technologies for separations and transmutation |publisher=National Academies Press |date=1996 |isbn=978-0-309-05226-9 |author=National Research Council (U.S.). Committee on Separations Technology and Transmutation Systems |url-status=live |archive-url=https://web.archive.org/web/20160613113140/https://books.google.com/books?id=iRI7Cx2D4e4C&pg=PA278 |archive-date=13 June 2016}}</ref>

[[File:Castle Bravo Blast.jpg|thumb|Lithium deuteride was used as fuel in the [[Castle Bravo]] nuclear device.]]
[[Lithium deuteride]] was the [[nuclear fusion|fusion fuel]] of choice in early versions of the [[Nuclear weapon|hydrogen bomb]]. When bombarded by [[neutron]]s, both <sup>6</sup>Li and <sup>7</sup>Li produce [[tritium]] — this reaction, which was not fully understood when [[Teller-Ulam design|hydrogen bombs]] were first tested, was responsible for the runaway yield of the [[Castle Bravo]] [[nuclear test]]. Tritium fuses with [[deuterium]] in a [[Nuclear fusion|fusion]] reaction that is relatively easy to achieve. Although details remain secret, lithium-6 deuteride apparently still plays a role in modern [[nuclear weapons]] as a fusion material.<ref>{{Cite book |url={{google books |plainurl=y |id=yTIOAAAAQAAJ |page=39}} |page=39 |title=How nuclear weapons spread: nuclear-weapon proliferation in the 1990s |author=Barnaby, Frank |publisher=Routledge |date=1993 |isbn=978-0-415-07674-6 |url-status=live |archive-url=https://web.archive.org/web/20160609210558/https://books.google.com/books?id=yTIOAAAAQAAJ&pg=PA39 |archive-date=9 June 2016}}</ref>

[[Lithium fluoride]], when highly enriched in the lithium-7 isotope, forms the basic constituent of the fluoride salt mixture LiF-[[beryllium fluoride|BeF<sub>2</sub>]] used in [[molten salt reactor|liquid fluoride nuclear reactors]]. Lithium fluoride is exceptionally chemically stable and LiF-BeF<sub>2</sub> mixtures have low melting points. In addition, <sup>7</sup>Li, Be, and F are among the few [[nuclide]]s with low enough [[neutron cross-section|thermal neutron capture cross-sections]] not to poison the fission reactions inside a nuclear fission reactor.<ref group=note>Beryllium and fluorine occur only as one isotope, <sup>9</sup>Be and <sup>19</sup>F respectively. These two, together with <sup>7</sup>Li, as well as [[deuterium|<sup>2</sup>H]], <sup>11</sup>B, <sup>15</sup>N, <sup>209</sup>Bi, and the stable isotopes of C, and O, are the only nuclides with low enough thermal neutron capture cross sections aside from [[actinide]]s to serve as major constituents of a molten salt breeder reactor fuel.</ref><ref>{{cite journal |last1=Baesjr |first1=C. |title=The chemistry and thermodynamics of molten salt reactor fuels |journal=Journal of Nuclear Materials |volume=51 |issue=1 |pages=149–162 |date=1974 |doi=10.1016/0022-3115(74)90124-X |bibcode=1974JNuM...51..149B |url=https://digital.library.unt.edu/ark:/67531/metadc1028644/ |osti=4470742 |access-date=28 June 2019 |archive-date=13 March 2021 |archive-url=https://web.archive.org/web/20210313170619/https://digital.library.unt.edu/ark:/67531/metadc1028644/ |url-status=live}}</ref>

In conceptualized (hypothetical) nuclear [[fusion power]] plants, lithium will be used to produce tritium in [[Magnetic confinement fusion|magnetically confined reactors]] using [[deuterium]] and [[tritium]] as the fuel. Naturally occurring tritium is extremely rare and must be synthetically produced by surrounding the reacting [[Plasma (physics)|plasma]] with a 'blanket' containing lithium, where neutrons from the deuterium-tritium reaction in the plasma will fission the lithium to produce more tritium:
:<sup>6</sup>Li + n → <sup>4</sup>He + <sup>3</sup>H.

Lithium is also used as a source for [[alpha particle]]s, or [[helium]] nuclei. When <sup>7</sup>Li is bombarded by accelerated [[proton]]s <sup>8</sup>[[beryllium|Be]] is formed, which almost immediately undergoes fission to form two alpha particles. This feat, called "splitting the atom" at the time, was the first fully human-made [[nuclear reaction]]. It was produced by [[John Douglas Cockcroft|Cockroft]] and [[Ernest Walton|Walton]] in 1932.<ref>{{Cite book |url={{google books |plainurl=y |id=XyOBx2R2CxEC |page=139}} |page=139 |title=Nobel Prize Winners in Physics |author=Agarwal, Arun |publisher=APH Publishing |date=2008 |isbn=978-81-7648-743-6 |url-status=live |archive-url=https://web.archive.org/web/20160629143432/https://books.google.com/books?id=XyOBx2R2CxEC&pg=PA139 |archive-date=29 June 2016}}</ref><ref>[http://www-outreach.phy.cam.ac.uk/camphy/cockcroftwalton/cockcroftwalton9_1.htm "'Splitting the Atom': Cockcroft and Walton, 1932: 9. Rays or Particles?"] {{webarchive|url=https://web.archive.org/web/20120902195556/http://www-outreach.phy.cam.ac.uk/camphy/cockcroftwalton/cockcroftwalton9_1.htm |date=2 September 2012 }} Department of Physics, University of Cambridge</ref> Injection of lithium powders is used in fusion reactors to manipulate plasma-material interactions and dissipate energy in the hot thermo-nuclear fusion plasma boundary.<ref>{{Cite web |url=https://phys.org/news/2011-11-lithium.html |title=With lithium, more is definitely better |website=phys.org}}</ref><ref>{{Cite web |url=https://phys.org/news/2021-11-hot-cores-cool-edges-fusion.html |title=Integrating hot cores and cool edges in fusion reactors |website=phys.org |access-date=23 April 2023 |archive-date=29 April 2023 |archive-url=https://web.archive.org/web/20230429103823/https://phys.org/news/2021-11-hot-cores-cool-edges-fusion.html |url-status=live}}</ref>

In 2013, the US [[Government Accountability Office]] said a shortage of lithium-7 critical to the operation of 65 out of 100 American nuclear reactors "places their ability to continue to provide electricity at some risk." The problem stems from the decline of US nuclear infrastructure. The equipment needed to separate lithium-6 from lithium-7 is mostly a cold war leftover. The US shut down most of this machinery in 1963, when it had a huge surplus of separated lithium, mostly consumed during the twentieth century. The report said it would take five years and $10 million to $12 million to reestablish the ability to separate lithium-6 from lithium-7.<ref name="nyt1013" />

Reactors that use lithium-7 heat water under high pressure and transfer heat through heat exchangers that are prone to corrosion. The reactors use lithium to counteract the corrosive effects of [[boric acid]], which is added to the water to absorb excess neutrons.<ref name="nyt1013">{{cite news |url=https://www.nytimes.com/2013/10/09/business/energy-environment/report-says-a-shortage-of-nuclear-fuel-looms.html |title=Report Says a Shortage of Nuclear Ingredient Looms |author=Wald, Matthew L. |date=8 October 2013 |work=The New York Times |url-status=live |archive-url=https://web.archive.org/web/20170701025300/http://www.nytimes.com/2013/10/09/business/energy-environment/report-says-a-shortage-of-nuclear-fuel-looms.html |archive-date=1 July 2017}}</ref>