Fuel, at least according to Wiki [1], runs about 28% the cost of a nuclear plant's operating expenses. And our current nuclear tech was chosen largely because it was cheap. You're also looking at much greater expenses in running breeder plants. Those are already pretty substantial costs. And now on top of the cost extracting/refining/enriching fuel from saltwater would cost, you also have to keep basic economics in mind as well. Right now there's little demand for nuclear material, and so this is reflect in its cost. However, should this change you'd expect to see the cost change in turn, and likely quite sharply. That's a lot of stuff piling up pretty fast!
I'm not sure where you're getting he millions of years for breeders. The article mentions the value I've seen pretty much everywhere which saltwater extraction could theoretically provide enough material for about 60k years of nuclear operation. And breeders could ideally reduce consumption to a bit less than 1% of current usage. So that'd be 6 million years, but that's at current consumption rates. If we replaced our energy with nuclear that'd be a 25 fold increase in usage so we're down to 240k years at current rates. And that's in the scenario where we're extracting all the material we can from ocean water, using every single resource we have on the planet, and doing it all with perfectly functioning breeder reactors.
Just seems we should be targeting something that isn't a numbers game, though granted you can probably make some argument that cobalt will be a limiter on solar but solar also comes with many other perks - decentralization, minimal danger from failure, much cheaper, practically infinite energy availability, and so on. The only issue is storing energy, but this can be done affordably in numerous ways even with present day tech - and decentralization can also remove lots of the burden here.
So only, say 100K years before we have to figure out fusion or something? I'm thinking we could live with that.
However, uranium in seawater is actually in an equilibrium, so the more we extract, the more gets dissolved from rocks. Effectively it's a renewable resource:
Whether breeders would be more expensive depends on their design. One that looks quite economical, according to independent engineers who evaluated it, is Moltex:
I'm not sure where you're getting he millions of years for breeders. The article mentions the value I've seen pretty much everywhere which saltwater extraction could theoretically provide enough material for about 60k years of nuclear operation. And breeders could ideally reduce consumption to a bit less than 1% of current usage. So that'd be 6 million years, but that's at current consumption rates. If we replaced our energy with nuclear that'd be a 25 fold increase in usage so we're down to 240k years at current rates. And that's in the scenario where we're extracting all the material we can from ocean water, using every single resource we have on the planet, and doing it all with perfectly functioning breeder reactors.
Just seems we should be targeting something that isn't a numbers game, though granted you can probably make some argument that cobalt will be a limiter on solar but solar also comes with many other perks - decentralization, minimal danger from failure, much cheaper, practically infinite energy availability, and so on. The only issue is storing energy, but this can be done affordably in numerous ways even with present day tech - and decentralization can also remove lots of the burden here.
[1] - https://en.wikipedia.org/wiki/Economics_of_nuclear_power_pla...