I have always felt the problem of fission waste disposal has been overblown.
If the goal is "walk away safe", then fission fuel is walk away safe in about 300 years too. The high level radiation emitted by the fission products comes from cesium and strontium and in 300 years, it will all be gone. Leaving low level radioactives, Uranium and a tiny amount of plutonium. In 300 years, the used rods will emit the same level of radiation as the unused rods. Since plutonium is an alpha emitter, the used rod will effectively not emit any radiation from plutonium. You could store one under your couch and not suffer any ill effects.
Reason why the US doesn't reprocess nuclear fuel rods anymore is that the Dept of Energy realized that as long as the fuel pellets remain intact, the uranium and plutonium is entrapped in the metallurgical structure of the fuel pellets. For the uranium and plutonium to be released back into the environment they will have to be melted down. If the pellets are unchanged, we could probably recycle them back into a new reactor in 300 years even.