I don't get why you think there's an open problem. 20% of US energy currently comes from nuclear. If waste is an open problem - what problem is it causing now?

I don't get why you think there's an open problem. 20% of US energy currently comes from nuclear. If waste is an open problem - what problem is it causing now? Would scaling nuclear related problems by a factor of five be better or worse than current energy problems? My view is that it would be better.