The estimates range from 80 years to hundreds of thousands of years, depending on the assumptions made, including: Possible sources (land mining, sea refining), current consumption level, efficiency of reactors. Where it is approximately this:
Mining land uranium at current consumption (i.e., no new nuclear): 80-250 years.
Refining uranium from sea: 5000-500.000 years.
Overall, it seems to me that just assuring that we have resources for hundreds of thousands of years is a bit misleading or at least undisclosed strong optimism.
I'd be happy to have a more scientific source with reliable information.
[1] https://bettermeetsreality.com/how-much-uranium-is-left-in-t...
Do you know that you could fit the whole amount of nuclear waste on a ridiculously small surface? That's not for no reason uranium works: it's extremely dense in energy, and the same goes for its waste.
there's also apparently asteroid uranium resources, and with SpaceX making it progressively possible to have payload delivered with economies of scale such industry may start in space once it makes economic sense.
Now, if we use 30Mt for the next 60 years, it doesn't look like enough Uranium for the next 1000 years... (even without considering the fact that those 50Mt of uncovential resources are probably not usable)