Editing Depleted uranium (section)

==Definition==
Natural uranium contains about {{percentage|0.72|100|2}} <sup>235</sup>U. Depleted uranium has lower [[mass fraction (chemistry)|mass fractions]]—up to three times less—of <sup>235</sup>U and [[Uranium-234|<sup>234</sup>U]] than natural uranium. Since <sup>238</sup>U has a much longer [[half-life]] than the lighter isotopes, DU is about 40% less radioactive than natural uranium.<ref name="McDiarmid 2001 123" /><ref>{{cite journal |last1=Sztajnkrycer |first1=Matthew D. |date=March 2004 |title=Chemical and Radiological Toxicity of Depleted Uranium |journal=Military Medicine |volume=169 |issue=3 |pages=212–216 |doi=10.7205/milmed.169.3.212 |pmid=15080241 |quote=By its very nature, DU contains only 50% to 60% of the radioactivity of naturally occurring uranium. |doi-access=free}}</ref><ref name="USOSD">[http://www.gulflink.osd.mil/du_ii/du_ii_tabc.htm "Properties and Characteristics of DU"] {{Webarchive|url=https://web.archive.org/web/20130218165322/http://www.gulflink.osd.mil/du_ii/du_ii_tabc.htm|date=18 February 2013}} U.S. Office of the Secretary of Defense</ref> Most of the [[alpha radiation]] comes from <sup>238</sup>U and <sup>234</sup>U<ref group="notes">In natural uranium, about 49% of the radiation comes from <sup>238</sup>U, 49% from <sup>234</sup>U, and 2% from <sup>235</sup>U. In depleted uranium the amounts of <sup>235</sup>U and <sup>234</sup>U are both reduced, but there is still much more radiation from the <sup>234</sup>U than from the <sup>235</sup>U.{{Citation needed|date=November 2024}}</ref> whereas [[beta radiation]] comes from decay products [[Thorium-234|<sup>234</sup>Th]] and [[Protactinium|<sup>234</sup>Pa]] that are formed within a few weeks.{{Clarify|reason=A few weeks of what?|date=November 2024}}{{Citation needed|date=November 2024}}

The United States [[Nuclear Regulatory Commission]] (NRC) defines ''depleted uranium'' as uranium with a percentage of the <sup>235</sup>U isotope that is less than {{percentage|0.711|100|3}} by weight (see [https://www.nrc.gov/reading-rm/doc-collections/cfr/part040/part040-0004.html 10 CFR 40.4]). The military specifications designate that the DU used by the [[U.S. Department of Defense]] (DoD) contain less than {{percentage|0.3|100|1}} <sup>235</sup>U.<ref name="Shelton" /> In actuality, DoD uses only DU that contains approximately {{percentage|0.2|100|1}} <sup>235</sup>U.<ref name="Shelton" />