1. Uranium in seawater is replenished by erosion through streams at a rate faster than we could ever burn it. It is effectively totally sustainable and even renewable on a 4+ billion year time frame, even without breeder reactors. But really, breeder reactors will become a thing when uranium gets expensive enough to warrant them. The reactors that were attempted so far just weren't needed because it turned out we had way more uranium that we originally thought.
2. With passive cooling systems, even seismically active regions can be powered by nuclear. Also, there are exciting possibilities for offshore nuclear, floating 10km out to sea where tsunami wavelengths are huge. Cooling is guaranteed and huge shipyards can do the construction. I agree that it's clear from Fukushima that designs requiring active cooling are no good in such places.
3. There are teams of nuclear engineers and other reactor designers in San Francisco right now at the American Nuclear Society meeting whose goal is to reduce the price of nuclear so that corporations can make a profit from them without compromising safety. I believe it can be done.
4. The Finns are about done with their deep geologic repository [1] and it's looking great. We definitely know how to dispose of nuclear waste. It's just a matter of political will and outreach. The tradeoff you have to keep in mind is that you can get all your primary energy for literally your entire life while personally producing 2 soda cans of nuclear waste. Compare that to fossil fuel (2 million times more waste) or to the vast energy harvesting resources for wind and solar (concrete bases, fiberglass, steel, silicon, glass, semiconductor processing, etc.) and you see that nuclear is extremely low footprint and that's its magic.
I sympathize with your concerns and am working to mitigate them. Biggest hurdle in my mind is standardizing designs. I dream of coordinating an open source reactor design effort some day.
[1] https://en.wikipedia.org/wiki/Onkalo_spent_nuclear_fuel_repo...
