Editing Hydrogen (section)

=== Niche and evolving uses ===
Other than the uses mentioned above, hydrogen is also used in smaller scales in the following applications:
*Shielding gas: Hydrogen is used as a [[shielding gas]] in [[welding]] methods such as [[atomic hydrogen welding]].<ref>{{cite journal
|last=Durgutlu| first=A.
|title=Experimental investigation of the effect of hydrogen in argon as a shielding gas on TIG welding of austenitic stainless steel
|journal=Materials & Design
|volume=25
|issue=1
|pages=19–23
|date=2003
|doi=10.1016/j.matdes.2003.07.004}}</ref><ref>{{Cite book |last1=Ujah |first1=Chika Oliver |url=https://onlinelibrary.wiley.com/doi/10.1002/9781394331925.ch6 |title=Advanced Welding Technologies |last2=N'Dedji Sodokin |first2=Rodolphe |last3=von Kallon |first3=Daramy Vandi |date=2025-05-05 |publisher=Wiley |isbn=978-1-394-33189-5 |editor-last=Kunar |editor-first=Sandip |edition=1 |pages=107–126 |language=en |chapter=Chapter 6 Atomic Hydrogen Welding |doi=10.1002/9781394331925.ch6 |editor-last2=Mandal |editor-first2=Gurudas}}</ref>

*Coolant: Hydrogen is used as a [[coolant]] in large power stations generators due to its high [[thermal conductivity]] and low density.<ref>{{Cite conference |last1=Kumar |first1=Rajendar |last2=Kumar |first2=Ashwani |date=June 2015 |title=Assessment of impact of hydrogen cooled generator on power system loadability enhancement |url=https://ieeexplore.ieee.org/document/7510166 |conference=2015 International Conference on Energy, Power and Environment: Towards Sustainable Growth (ICEPE) |publisher=IEEE |pages=1–6 |doi=10.1109/EPETSG.2015.7510166 |isbn=978-1-4673-6503-1}}</ref> The first [[hydrogen-cooled turbogenerator]] went into service using gaseous hydrogen as a [[coolant]] in the rotor and the stator in 1937 at [[Dayton, Ohio|Dayton]], Ohio.<ref>{{cite book|url=https://archive.org/stream/chronologicalhis00natirich/chronologicalhis00natirich_djvu.txt|title=A chronological history of electrical development from 600 B.C|author=National Electrical Manufacturers Association|year=1946|page=102|publisher=New York, N.Y., National Electrical Manufacturers Association|access-date=9 February 2016|archive-url=https://web.archive.org/web/20160304141424/http://www.archive.org/stream/chronologicalhis00natirich/chronologicalhis00natirich_djvu.txt|archive-date=4 March 2016|url-status=live}}</ref>

*Cryogenic research: Liquid {{chem2|H2}} is used in [[cryogenic]] research, including [[superconductivity]] studies.<ref>{{cite journal
|last=Hardy
|first=W. N.
|title=From H2 to cryogenic H masers to HiTc superconductors: An unlikely but rewarding path
|journal=Physica C: Superconductivity
|volume=388–389
|pages=1–6
|date=2003
|doi=10.1016/S0921-4534(02)02591-1|bibcode = 2003PhyC..388....1H }}</ref>
*Leak detection: Pure or mixed with nitrogen (sometimes called [[forming gas]]), hydrogen is a [[tracer gas]] for [[Leak detection|detection]] of minute leaks. Applications can be found in the automotive, chemical, power generation, aerospace, and telecommunications industries.<ref>{{cite conference
|first=M.
|last=Block
|title=Hydrogen as Tracer Gas for Leak Detection
|work=16th WCNDT 2004
|publisher=Sensistor Technologies
|date=3 September 2004
|location=Montreal, Canada
|url=http://www.ndt.net/abstract/wcndt2004/523.htm
|access-date=25 March 2008
|archive-url=https://web.archive.org/web/20090108102521/http://www.ndt.net/abstract/wcndt2004/523.htm
|archive-date=8 January 2009
}}</ref> Hydrogen is an authorized food additive (E 949) that allows food package leak testing, as well as having anti-oxidizing properties.<ref>{{cite web
|url=http://ec.europa.eu/food/fs/sfp/addit_flavor/flav15_en.pdf
|title=Report from the Commission on Dietary Food Additive Intake
|publisher=[[European Union]]
|access-date=5 February 2008
|archive-url=https://web.archive.org/web/20080216050325/http://ec.europa.eu/food/fs/sfp/addit_flavor/flav15_en.pdf
|archive-date=16 February 2008
|url-status=live
}}</ref>

*Neutron moderation: [[Deuterium]] (hydrogen-2) is used in [[CANDU reactor|nuclear fission applications]] as a [[neutron moderator|moderator]] to slow [[neutron]]s.
*Nuclear fusion fuel: Deuterium is used in [[nuclear fusion]] reactions.<ref name="nbb" />
*Isotopic labeling: Deuterium compounds have applications in chemistry and biology in studies of [[Kinetic isotope effect|isotope effects]] on reaction rates.<ref>{{cite journal|last1=Reinsch| first1=J.|first2=A. |last2=Katz|first3=J.|last3=Wean|first4=G.|last4=Aprahamian|first5=J. T.|last5=MacFarland
|title=The deuterium isotope effect upon the reaction of fatty acyl-CoA dehydrogenase and butyryl-CoA| journal=J. Biol. Chem.|volume=255
|issue=19|pages=9093–97|date=1980| doi=10.1016/S0021-9258(19)70531-6|pmid=7410413|doi-access=free}}</ref>

*Tritium uses: [[Tritium]] (hydrogen-3), produced in [[nuclear reactor]]s, is used in the production of [[hydrogen bomb]]s,<ref>{{cite journal| last=Bergeron| first=K. D.| title=The Death of no-dual-use| journal=Bulletin of the Atomic Scientists| volume=60| issue=1| pages=15–17| date=2004| url=http://find.galegroup.com/itx/start.do?prodId=SPJ.SP06| doi=10.2968/060001004| access-date=13 April 2008| archive-url=https://web.archive.org/web/20080419051641/http://find.galegroup.com/itx/start.do?prodId=SPJ.SP06| archive-date=19 April 2008| url-status=live| bibcode=2004BuAtS..60a..15B}}</ref> as an isotopic label in the biosciences,<ref name="holte" /> and as a source of [[beta particle|beta radiation]] in [[Tritium radioluminescence|radioluminescent paint]] for instrument dials and emergency signage.<ref name="Traub95" />