...if the alternative is climate change continuing to worsen until renewable technologies (particularly energy storage and transmission) are up to par and scale, which one do you prefer?
That's a tough call, but I'd prefer pushing harder on renewable research or finding a permanent solution to the nuclear waste problem, because, as bad as humans are at dealing with medium term consequences of our activities (see climate change), we have no track record of dealing with the long term, and ultra-long term consequences of what we do.