> Uranium is a naturally occurring element found in low levels in all rock, soil, and water. It is the highest-numbered element found naturally in significant quantities on Earth and is almost always found combined with other elements.[12] Uranium is the 48th most abundant element in the Earth’s crust.[60] The decay of uranium, thorium, and potassium-40 in Earth's mantle is thought to be the main source of heat[61][62] that keeps the Earth's outer core in the liquid state and drives mantle convection, which in turn drives plate tectonics.
> Uranium's concentration in the Earth's crust is (depending on the reference) 2 to 4 parts per million,[11][22] or about 40 times as abundant as silver.[17] The Earth's crust from the surface to 25 km (15 mi) down is calculated to contain 10¹⁷ kg (2×10¹⁷ lb) of uranium while the oceans may contain 10¹³ kg (2×10¹³ lb).[11] The concentration of uranium in soil ranges from 0.7 to 11 parts per million (up to 15 parts per million in farmland soil due to use of phosphate fertilizers),[63] and its concentration in sea water is 3 parts per billion.[22]
> Uranium is more plentiful than antimony, tin, cadmium, mercury, or silver, and it is about as abundant as arsenic or molybdenum.[12][22] Uranium is found in hundreds of minerals, including uraninite (the most common uranium ore), carnotite, autunite, uranophane, torbernite, and coffinite.[12] Significant concentrations of uranium occur in some substances such as phosphate rock deposits, and minerals such as lignite, and monazite sands in uranium-rich ores[12] (it is recovered commercially from sources with as little as 0.1% uranium[17]).
Now, 0.1% uranium is 1000 parts per million, which is a lot more than 0.7 to 11. But that doesn't mean current technology is incapable of recovering uranium from these 300× lower concentrations. It's just that it requires processing 300× as much rock, which is expensive, so it can't compete in the market with more concentrated sources.
It doesn't affect the amount of energy required to enrich the uranium once it's been extracted from the rock, just the amount of energy required to extract the uranium from the rock. It just requires leaching the uranium from a larger amount of material.
I understand that you might randomly spread FUD like this if you haven't bothered to do any calculations at all because you don't care whether what you're saying is true or false. You're off by orders of magnitude.
https://en.wikipedia.org/wiki/Energy_density#Nuclear_reactio... says uranium as burned in a breeder reactor yields 80TJ/kg; if your soil contains 10ppm of uranium, you're getting 800MJ per kg of soil. Lignite coal is 10–20MJ/kg, so regular soil yields 40–80 times as much energy as a source of uranium as coal does as a source of carbon.
Or, looking at it a different way, to supply a given amount of energy from uranium, you only have to mine about 2% as much random soil as if you were mining coal from an open-air coal deposit. (Subsequent processing is somewhat different, involving leaching with sulfuric acid.) Since mining coal requires significantly less energy than the coal yields, uranium mining is not close to net-zero on its energy return anywhere in the world.
Nuclear reactors are not economically competitive with solar and PV, but that's a different issue.
Your calculations are ignoring the costs of enrichment - you can't just feed soil into your reactor - whereas you can just feed the raw coal into your furnace.
Now I freely admit I don't know the costs of enrichment. I just used your numbers - you said you'd just have to mine 300 times as much rock - and obviously that's 300 times more expensive - for something which is already not energy cheap.
ie to convince me you have to show the full costs of mining and enrichment, to the point you actually have a fuel that's reactor ready.
And even if that's net positive energy - I'd suspect you'd be much better in investing in wind, hydro, tidal and solar and a decent storage and grid system.
Sometimes I feel nuclear is fetishised because it's cool science - however I'm more interested in practical solutions, and if that means a simple wind or water turbine - so be it.
Happy to be convinced otherwise - but you need to show the numbers.
"Enrichment", in the context of nuclear power, doesn't mean extracting uranium from ore or purifying the uranium. "Enrichment" means increasing the percentage of fissionable ²³⁵U in the uranium. This process starts with extremely pure uranium, for example in the form of UF₆, so it's the same process regardless of how dilute the original uranium was. So the energy required for it doesn't depend on the concentration of the original uranium deposit.
In the case of things like coal, the energy cost of mining is significant compared to the energy obtained from it. In the case of uranium, simply because the amount of material processed is so small by comparison, it is not significant. As I showed above, it would not even be significant if you have to mine 300 times as much rock as uranium mining currently does.
Obviously you would be better off investing in wind, solar, and storage than in nuclear energy. (Hydroelectric and tidal are less clear wins.) But that's not because sufficiently concentrated uranium deposits are rare. On the contrary, there's literally nowhere on the planet where uranium is insufficiently concentrated.
> Uranium is a naturally occurring element found in low levels in all rock, soil, and water. It is the highest-numbered element found naturally in significant quantities on Earth and is almost always found combined with other elements.[12] Uranium is the 48th most abundant element in the Earth’s crust.[60] The decay of uranium, thorium, and potassium-40 in Earth's mantle is thought to be the main source of heat[61][62] that keeps the Earth's outer core in the liquid state and drives mantle convection, which in turn drives plate tectonics.
> Uranium's concentration in the Earth's crust is (depending on the reference) 2 to 4 parts per million,[11][22] or about 40 times as abundant as silver.[17] The Earth's crust from the surface to 25 km (15 mi) down is calculated to contain 10¹⁷ kg (2×10¹⁷ lb) of uranium while the oceans may contain 10¹³ kg (2×10¹³ lb).[11] The concentration of uranium in soil ranges from 0.7 to 11 parts per million (up to 15 parts per million in farmland soil due to use of phosphate fertilizers),[63] and its concentration in sea water is 3 parts per billion.[22]
> Uranium is more plentiful than antimony, tin, cadmium, mercury, or silver, and it is about as abundant as arsenic or molybdenum.[12][22] Uranium is found in hundreds of minerals, including uraninite (the most common uranium ore), carnotite, autunite, uranophane, torbernite, and coffinite.[12] Significant concentrations of uranium occur in some substances such as phosphate rock deposits, and minerals such as lignite, and monazite sands in uranium-rich ores[12] (it is recovered commercially from sources with as little as 0.1% uranium[17]).
Now, 0.1% uranium is 1000 parts per million, which is a lot more than 0.7 to 11. But that doesn't mean current technology is incapable of recovering uranium from these 300× lower concentrations. It's just that it requires processing 300× as much rock, which is expensive, so it can't compete in the market with more concentrated sources.