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.