Where's my uranium?

[Indalecio]

I've got a source of uranium, its mined, theres a road connecting it to one of my cities. But I can't build battleships, subs or carriers. I am pretty sure I didn't trade away to anyone.

Anyone know whats the story here? The save was too big to attach directly, but I included it here.

[Solver]

You probably don't have Fission yet.

[guermantes]

Indeed Uranium is a bit tricky since you can reveal it on the map and then go and mine it but you still don't get access to it unless you have researched Fission. I almost went to war once before I realized that...