I know several of my friends from my masters course are now working on accelerator driven sub-critical and fission-fusion hybrid designs. I think they are definitely viable way of disposing of the longer lied actinides.
But I do wonder at the cost and benefit of them. I still think the best way of getting rid of the waste is to just wait 50-100 years for the short live stuff to decay then drop the rest, encased in concrete, into an ocean trench.
