> As for the reprocessing part, I think you are jumping the gun. The problem is that if the pebbles aren't reprocessed, you now have to store their very large

> As for the reprocessing part, I think you are jumping the gun. The problem is that if the pebbles aren't reprocessed, you now have to store their very large volume. The moderator, graphite, is integrated into them. This is unlike a LWR, where the moderator is water that the spent fuel can be simply lifted out of (after cooling). LWR fuel can be stored after a few years into dry casks; the equivalent for pebbles would be vastly larger and more expensive, and involves storing the spent fuel with its moderator, increasing concerns of criticality (although I imagine they'd be doused with borate or something to prevent that).