Peak uranium is also an issue. Uranium mining output has plateaued, and the world currently consumes more uranium than is mined, dipping into the stockpiles to make up the difference. There's just not enough mineral uranium to fuel a world running on nuclear power. And while uranium is present in granite all over, there's no equivalent to fracking for uranium. Getting that uranium would take more energy than it could put out, so it wouldn't be economical, ever.
Breeder reactors? Nobody has gotten one to work in manner which is both safe and cost effective. We always hear about the new nuke technology just around the corner, but it never seems to bear fruit.
Having run reactors, I'm rather pro-nuclear. But I recognize the money problem. Nuclear power just costs too much. What we have is necessary for a baseline, but it's cheaper to build more renewable energy.