This is a very short-sighted take, that relies on the assumption Russians are comically corrupt and incompetent. I'm sure the mechanisms to prevent this sort of theft that are in place in the USA have similar analogues in Russia, starting with inspections of facilities and background checks of personnel.

The current three-day special operation has shown the world how incompetent and corrupt the russian leadership is, no need for gloves.

Personally, I don't think it's a good idea to underestimate an enemy like that.

Thinking the other side is incompetent or in the brink of losing is the kind of thinking kept the 20 year, $2.313 trillion Afghanistan War going, and we know how that ended.

But the corruption wouldn't necessarily be to sell the nuke materials. It could be something like allowing the maintenance team to staffed by nepobabies of important people, on the agreement that nothing is actually done. That way the general buys some favor with the state's money, the and the kids get an income for doing nothing.

The hard part would be finding a buyer. North Korea already has their own domestic capability, and Iran is using their current situation as a negotiating point. Beyond that, who would even want black market nuclear fuel?

It theoretically could happen at small scales though, eg. The Apollo Affair where Israel's nuclear program was allegedly kick-started by the illicit diversion of nuclear fuel from the US.

https://en.m.wikipedia.org/wiki/The_Apollo_Affair

> Beyond that, who would even want black market nuclear fuel?

Al Qaeda and other terrorist organizations would absolutely want it for the dirty bomb potential.