Uranium can be stockpiled for years in advance, relatively easily. Enough to tide over a small war while you're setting up domestic production. And China should have enough low-grade ores for that.
Uranium is better for Chinese energy security than oil. But this still leaves China at Moscow's mercy. That's not too differet, energywise, than the situation is now.
> Uranium is far, far energy denser than any fossil fuel, and thus much easier to stockpile
Sure. That doesn't remove stockpiles' inherent disadvantages: finiteness and vulnerability. Relying on uranium stockpiles would immediately put China at a known limit in a war of attrition that wouldn't constrain their adversaries.
A sufficiently large stockpile of uranium gives China time to simply pivot away from depending on imported Uranium (either by building new mines locally or building out solar or such). An equivalent stockpile of oil simply isn't feasible, if only because oil is usually used directly and not via a source-agnostic electrical grid.
I know. I am not saying I got the order of magnitude exactly right, just pointing out beyond a certain threshold the size of the stockpile doesn't matter. I suspect that if a nation state puts its mind to it, stockpiles great enough to last a war are totally possible.
That's not a stockpile, they have to extract and refine it to use it. Russia understood it the hard way with the refineries attacks.
And no, oil is more expensive (especially nowadays) to extract than uranium.
There's a reason nobody ever became rich with a uranium mine, all the value is in the plant and the market price barely covers extracting it, some mines even closed because of the price being too low.
We're not talking about ore, rather fuel. Uranium ore might be inexpensive, I don't know, but converting that ore into fuel is not an easy task. I'm guessing that the reason it's not profitable is that so little of it is actually needed, relative to oil.