High-level waste disposal is an element of paramount importance in the discussion of nuclear power generation sustainability. Hybrid installations that combine fusion devices and accelerator-driven spallation neutron sources with a subcritical fission reactors have been proposed as waste solution.

The hybrid systems could both produce energy and transmute the actinides and fission products. The fission blanket of such a hybrid system has enhanced safety characteristics and excludes reactivity accidents due to its subcriticality.