> and only available from pre-war / pre-atomic sources.
From the same wiki you linked:
"Since the end of atmospheric nuclear testing, background radiation has decreased to very near natural levels, making special low-background steel no longer necessary for most radiation-sensitive uses, as brand-new steel now has a low enough radioactive signature"
and
"For the most demanding items even low-background steel can be too radioactive and other materials like high-purity copper may be used"
From the same wiki you linked:
"Since the end of atmospheric nuclear testing, background radiation has decreased to very near natural levels, making special low-background steel no longer necessary for most radiation-sensitive uses, as brand-new steel now has a low enough radioactive signature"
and
"For the most demanding items even low-background steel can be too radioactive and other materials like high-purity copper may be used"