[HyperSane]

Coal contains between 1 to 10 ppm of uranium. Globally about 8 billion tonnes of coal is burned every year to generate electricity. Thus between 8 thousand and 80 thousand tonnes of Uranium is emitted into the atmosphere every year.

[Filligree]

Which… I’m not sure, but that might be more uranium than would be needed in the first place to run our entire civilisation on nuclear power?

Certainly it’s in the ballpark.

[cinntaile]

It's not a a useful measure, since no one would collect uranium in this way but assuming someone would. Some napkin math... 27 tonnes per 1GW reactor/year is used and there are about 440 reactors so about 12kton.

[p_l]

Just current reserves, with breeder fuel cycles, would allow us at least a century, long enough to start building in space...