> However, seawater concentrations of uranium are controlled by steady-state, or pseudo-equilibrium, chemical reactions between waters and rocks on the Earth, both in the ocean and on land. And those rocks contain 100 trillion tons of uranium. So whenever uranium is extracted from seawater, more is leached from rocks to replace it, to the same concentration. It is impossible for humans to extract enough uranium over the next billion years to lower the overall seawater concentrations of uranium, even if nuclear provided 100% of our energy and our species lasted a billion years
"Current nuclear technology isn't sufficient either. A world powered by nuclear burner reactors runs out of uranium very quickly. Breeder reactors or seawater uranium extraction would be needed, and neither of these are "existing" in the sense you're using for storage" (emphasis added)
So, your comment about seawater there doesn't contradict what I wrote at all.
> And these advances by PNNL and ORNL have reduced the cost by a factor of four in just five years. But it’s still over $200/lb of U3O8, twice as much as it needs to be to replace mining uranium ore.
> Fortunately, the cost of uranium is a small percentage of the cost of nuclear fuel, which is itself a small percentage of the cost of nuclear power. Over the last twenty years, uranium spot prices have varied between $10 and $120/lb of U3O8, mainly from changes in the availability of weapons-grade uranium to blend down to make reactor fuel.
> So as the cost of extracting U from seawater falls to below $100/lb, it will become a commercially viable alternative to mining new uranium ore. But even at $200/lb of U3O8, it doesn’t add more than a small fraction of a cent per kWh to the cost of nuclear power.
This is technology that actually has a demonstrated cost. Moreover it doesn't need to get cheaper at scale since raw extraction is such a small portion of nuclear power's cost. It's not like synthetic methane or hydrogen storage where it's all white papers promising cheap cost, but not actually delivering any storage systems at that cost.
Extracting uranium from seawater on the scale needed to fuel burner reactors requires massive engineering. The estimate I've seen is that fueling one 1 GWe burner reactor takes a seafloor uranium absorption field (suspended in a strong ocean current; if you have to pump the seawater yourself it's already too expensive) of 170 square kilometers. The power/area is already much lower than the time-averaged output from PV.
Extrapolating from the lab bench to 170 sq. kilometers (x 6000 for the number of reactors needed to power a nuclear world) is a far larger stretch than extrapolating renewables and storage to what they would need. Your selective doubt is not being driven by any honest impulse.
All I demand is that people deliver at the specified cost. Not, for example, a prototype with unspecified cost or a pilot program with much higher cost to and promises that it'll get cheaper at scale.
> Extrapolating from the lab bench to 170 sq. kilometers (x 6000 for the number of reactors needed to power a nuclear world) is a far larger stretch than extrapolating renewables and storage to what they would need. Your selective doubt is not being driven by any honest impulse.
I could say the same about you. Nobody is seriously considering pumping seawater to filter uranium. This is a totally bad faith argument.
And you give this estimate of 170 without actually giving a source for it nor specifying details like how far apart the buoys are spaced, or if reprocessing is used (which cuts down fuel use by more than an order of magnitude).
To power the world with nuclear would require many more reactors. Current world average primary energy consumption is 18 TW, which is 6000 3 GWth reactors. That's an order of magnitude more than currently are in operation. Add in demand growth from industrializing countries and the uranium would last maybe a decade.
Uranium availability is not an immediate problem if you assume nuclear remains a sideshow on the global energy stage. That's to assume nuclear is neither needed nor particularly useful for addressing global warming. Is that what you're assuming?