"[O]ne of the reasons we want to do this is because we want to drive... an . This is where you take a , a fission reactor. In the core, instead of having , it has an element called , which is... much more abundant, and you don't have to refine it. You can use all of it. Hook up to the reactor a particle accelerator, a very high power proton accelerator. So the protons come in and they smash into a heavy metal target and create s... [T]hose neutrons... drive the reaction in the reactor, so without the accelerator there, the reactor is subcritical. It doesn't produce energy. It doesn't sustain a , but once you add in the accelerator you can continue to drive the reaction and generate energy... [I]n fact you could transmute existing nuclear waste into something much shorter lived and much safer."