Nuclear isn't viable. Nobody has figured out how to deal with the waste. Hence it piling up in 'storage ponds'. The folly that we can predict it won't be disturbed for 1000x the length our modern society has existed is laughable. (all that said, nuclear is totally required for the next 50-100 years to deal with climate change)
On that front, my favorite, actually realistic, plan to deal with nuclear waste is to launch it into the sun. Seriously. The entire earth could, err will, be consumed by the Sun and it won't so much as burp. We can totally just throw all of our waste into it with literally zero downsides.
Just a bit economically unfeasible though, at least for now. The real fun fact is it's 'cheaper' to launch that waste out to Pluto and then send it into the Sun. I blame physics ;-)