[ImminentFate]

As of 2009, estimates were that we have between 200-400 years of nuclear fuel remaining at current consumption rates.

If we can efficiently extract uranium from saltwater, that value jumps to 60,000 years.

If instead we switch all reactors over to breeder types instead of the current light-water reactors, our 200-400 year estimate then becomes more like 30,000 years

[Beltiras]

Replace Uranium with Thorium and you get another increase in high-energy lifespan for humans by tens of thousands.