@cstross @kierkegaank
It's probably not the fuel elements themselves that aren't made anymore, but rather something like #fogbank, a mysterious chemical substance that was used in the creation of nuclear weapons, the formula for which was kept so secret that it was never written down, and now nobody knows how to make it anymore.
https://www.thedrive.com/the-war-zone/32867/fogbank-is-mysterious-material-used-in-nukes-thats-so-secret-nobody-can-say-what-it-is

Will you be able to tame the power of the #FOGBANK internal development document that Nancy #Pelosi has in her kitchen for some reason?