Low-background steel: Difference between revisions

Since the end of [[atmospheric nuclear testing]], [[background radiation]] has decreased to very near natural levels,<ref name="UNSCEAR" /> making special low-background steel no longer necessary for most radiation-sensitive uses, as brand-new steel now has a low enough radioactive signature that it can generally be used.<ref name="dope" /> Some demand remains for the most radiation-sensitive uses, such as [[Geiger counter]]s and sensing equipment aboard spacecraft. For the most demanding items even low-background steel can be too radioactive and other materials like high-purity copper may be used.<ref name=Mandelbaum />

 

 

==Radionuclide contamination==

[[History of the modern steel industry|From 1856 until the mid 20th century]], steel was produced in the [[Bessemer process]], where [[air]] was forced into Bessemer converters converting the [[pig iron]] into [[steel]]. By the mid-20th century, many steelworks had switched to the [[Basic oxygen steelmaking|BOS process]], which uses pure [[oxygen]] instead of air. However, as both processes use atmospheric gas, they are susceptible to contamination from airborne particulates. Present-day air carries [[radionuclide]]s, such as [[cobalt-60]], which are deposited into the steel, giving it a weak radioactive signature.<ref name="dope">{{cite web |url=http://www.straightdope.com/columns/read/2971/is-steel-from-scuttled-german-warships-valuable-because-it-isn-t-contaminated-with-radioactivity |title=Is steel from scuttled German warships valuable because it isn't contaminated with radioactivity? |website=The Straight Dope |date=10 December 2010 |first=Cecil |last=Adams}}</ref> Another source of radioactive contamination was the coating of steel cauldrons in cobalt-60 in order to monitor wear.<ref name=Oelbaum>{{cite news |last=Oelbaum |first=Jed |date=10 May 2018 |title=The Worldwide Scavenger Hunt For Vintage, Low-Radiation Metals |url=https://www.good.is/articles/the-search-for-low-background-steel |work=Good.is |access-date=27 May 2023}}</ref> Steel that would otherwise be expected to be low-background can itself be contaminated due to [[thorium]] in welding rods.<ref name=Mandelbaum>{{cite news |last=Mandelbaum |first=Ryan F. |date=19 December 2017 |title=How Physicists Recycled WWII Ships And Artillery To Unlock The Mysteries Of The Universe |url=https://www.gizmodo.com.au/2017/12/how-physicists-recycled-wwii-ships-and-artillery-to-unlock-the-mysteries-of-the-universe/ |work=Gizmodo |access-date=25 May 2023}}</ref>

 

 

==References==