Howabout tidal energy or other sources of energy that aren't being harnessed?
The problem is that we haven't figured out how to use wind or waves or solar in the way that we use nuclear. Long story short, if there is an intense demand spike right now, you local nuclear power plant can handle it while others probably can't. No cloudy days with nuclear either.
One reason nuclear technology is so advanced is that the world spent trillions on nuke research in order to build bombs. If we had figured a way to use solar bombs solar might be advanced to the point we could use it as efficiently as nuke power.
As far as I know we have no clue how to properly dispose of the waste. Reprocessing just separates the components (I need to understand this better). No matter what you do right now you are going to end up with something that takes 20,000 years to decay.
Keep stuffing dangerous stuff in the ground that doesn't go away for 20,000 years and eventually something is going to snap.