Editing Beryllium (section)

===Nuclear applications===
High purity beryllium can be used in nuclear reactors as a moderator,<ref>{{Citation |last=Sicius |first=Hermann |title=Alkaline Earth Metals: Elements of the Second Main Group |date=2024 |work=Handbook of the Chemical Elements |pages=77–139 |url=https://link.springer.com/10.1007/978-3-662-68921-9_2 |access-date=2025-03-05 |place=Berlin, Heidelberg |publisher=Springer Berlin Heidelberg |language=en |doi=10.1007/978-3-662-68921-9_2 |isbn=978-3-662-68920-2}}</ref> reflector, or as cladding on fuel elements.<ref>Beeston, J. M. (1971). Beryllium metal as a neutron moderator and reflector material. Nuclear engineering and design, 14(3), 445-474.</ref><ref>A. Tomberlin T. (2004). Beryllium-a unique material in nuclear applications. Idaho Falls, ID: Idaho National Laboratory.</ref>
Thin plates or foils of beryllium are sometimes used in [[nuclear weapon design]]s as the very outer layer of the [[plutonium pit]]s in the primary stages of [[thermonuclear bomb]]s, placed to surround the [[fissile]] material. These layers of beryllium are good "pushers" for the [[implosion (mechanical process)|implosion]] of the [[plutonium-239]], and they are good [[neutron reflector]]s, just as in beryllium-moderated [[nuclear reactors]].<ref name="weapons" />

Beryllium is commonly used in some [[neutron source]]s in laboratory devices in which relatively few neutrons are needed (rather than having to use a nuclear reactor or a [[particle accelerator]]-powered [[neutron generator]]). For this purpose, a target of beryllium-9 is bombarded with energetic alpha particles from a [[radioisotope]] such as [[polonium]]-210, [[radium]]-226, [[plutonium]]-238, or [[americium]]-241. In the nuclear reaction that occurs, a beryllium nucleus is [[Nuclear transmutation|transmuted]] into carbon-12, and one free neutron is emitted, traveling in about the same direction as the alpha particle was heading. Such [[alpha decay]]-driven beryllium neutron sources, named [[Modulated neutron initiator|"urchin"]] neutron initiators, were used in some early [[atomic bomb]]s.<ref name="weapons">{{Cite book|url=https://books.google.com/books?id=yTIOAAAAQAAJ&pg=PA35|page=35|title=How nuclear weapons spread|author=Barnaby, Frank|publisher=Routledge|date=1993|isbn=978-0-415-07674-6|access-date=30 October 2021|archive-date=27 July 2020|archive-url=https://web.archive.org/web/20200727094353/https://books.google.com/books?id=yTIOAAAAQAAJ&pg=PA35|url-status=live}}</ref> Neutron sources in which beryllium is bombarded with [[gamma ray]]s from a [[gamma decay]] radioisotope are also used to produce laboratory neutrons.<ref name="Byrne-2011">Byrne, J. ''Neutrons, Nuclei, and Matter'', Dover Publications, Mineola, NY, 2011, {{ISBN|0-486-48238-3}}, pp. 32–33.</ref>

[[File:CANDU fuel bundles.jpg|right|thumb|upright=1.6|Two CANDU fuel bundles: Each about 50&nbsp;cm in length and 10&nbsp;cm in diameter. Notice the small appendages on the fuel clad surfaces]]

Beryllium is used in fuel fabrication for [[CANDU]] reactors. The fuel elements have small appendages that are resistance brazed to the fuel cladding using an induction brazing process with Be as the braze filler material. Bearing pads are brazed in place to prevent contact between the fuel bundle and the pressure tube containing it, and inter-element spacer pads are brazed on to prevent element to element contact.<ref>Harmsen, J. G., Lewis, B. J., Pant, A., & Thompson, W. T. (2010, October). Beryllium brazing considerations in CANDU fuel bundle manufacture. In Proceedings of the Eleventh Conference on CANDU Fuel, Niagara Falls, ON (pp. 1-12).</ref>

Beryllium is used at the [[Joint European Torus]] [[nuclear fusion|nuclear-fusion research laboratory]], and it will be used in the more advanced [[ITER]] to condition the components which face the plasma.<ref>{{Cite book|url=https://books.google.com/books?id=9ngHTkC8hG8C&pg=PA15|page=15|title=Nuclear fusion research|author=Clark, R. E. H.|author2=Reiter, D.|publisher=Springer|date=2005|isbn=978-3-540-23038-0|access-date=30 October 2021|archive-date=27 July 2020|archive-url=https://web.archive.org/web/20200727091926/https://books.google.com/books?id=9ngHTkC8hG8C&pg=PA15|url-status=live}}</ref> Beryllium has been proposed as a [[Cladding (nuclear fuel)|cladding]] material for [[nuclear fuel rod]]s, because of its good combination of mechanical, chemical, and nuclear properties.<ref name="Behrens-2003" /> [[Beryllium fluoride]] is one of the constituent salts of the eutectic salt mixture [[FLiBe]], which is used as a solvent, moderator and coolant in many hypothetical [[molten salt reactor]] designs, including the [[liquid fluoride thorium reactor]] (LFTR).<ref>{{Cite journal|doi=10.1016/j.fusengdes.2005.08.101|title=JUPITER-II molten salt Flibe research: An update on tritium, mobilization and redox chemistry experiments|date=2006|last1=Petti|first1=D.|last2=Smolik|first2=G.|last3=Simpson|first3=M.|last4=Sharpe|first4=J.|last5=Anderl|first5=R.|last6=Fukada|first6=S.|last7=Hatano|first7=Y.|last8=Hara|first8=M.|last9=Oya|first9=Y.|journal=[[Fusion Engineering and Design]]|volume=81|page=1439|issue=8–14|bibcode=2006FusED..81.1439P |osti=911741|display-authors=8|url=https://digital.library.unt.edu/ark:/67531/metadc885108/|access-date=30 October 2021|archive-date=26 April 2021|archive-url=https://web.archive.org/web/20210426171553/https://digital.library.unt.edu/ark:/67531/metadc885108/|url-status=live}}</ref>