Ah that’s breeders, it’s a different game. They’re technically more challenging (the French spent billions on their plants which didn't quite deliver) and have a significant nuclear weapons proliferation risk.
Somewhere I read (sorry for the lack of sources) that with single-pass fuel use, known reserves would only last a couple decades, a century at best.
A global buildout of breeders is the issue. The rich countries telling the poor countries they can’t have nice things because of “our” security concerns. Big talking point in the 1960s. Tom Lehrer even wrote a cute song about nuclear proliferation in 1964, “Who’s Next?”.
If you get any expansive policy and process wrong, the negative global consequences are dramatic and long-lasting. So, first, do no harm.
Somewhere I read (sorry for the lack of sources) that with single-pass fuel use, known reserves would only last a couple decades, a century at best.