It's solved if your government gets off its ass about it. Reprocessing waste for reactors is one of the few places where nuclear makes sense. Way better than burying it for thousands of years.

Otherwise, the economics have ran past it. We have solutions without it; we just need to scale the up. There are a few other niches, like cargo ships, where they make sense. For general power use, no.

The issue is not the volume it is the duration.