Is it viable to convert nuclear waste into safe isotopes? I read that powerful pulsed lasers can change isotopes:
J. Magill, et. al.: "Laser transmutation of iodine-129".
Did anyone estimate what would be the energy costs to transmutate 1 kg of fission product from a conventional reactor using such a laser or an accelerator?
Is it even possible to transmutate a mixture of isotopes?
Would that be a viable alternative to long term storage if we find a way to get enough energy?
Right now I seriously doubt that we could ever process 100s of kilograms using such techniques.
 A: The funny thing is that in the case described in the paper, pretty safe isotope (I-129) was converted into deadly dangerous I-128, I would prefer to leave it as is :-)
Transmutating random mix of isotopes would give you more random mix of isotopes (garbage in->garbage out), and it's a big question if this would lead to lower integral activity.
So to transmutate isotopes sensibly, we would need to separate waste into individual isotopes first. Another funny thing is that it would automagically solve the problem - as separated radioactive isotopes are all precious - part of them may be turned back to fuel (mainly U, Pt) , part of them may be used for radioisotope sources of energy, and the rest sold for medical & industrial equipment, or stored much more compact or safe than it is now. The problem is that it's not very commercially viable to process all fuel at the moment - only relatively small part of waste is processed (on 'Mayak' in Russia for example).
A: I may illustrate the already mentioned problem with mixture of many isotopes. Why only I-129 is chosen? In the paper it is compared with only two isotopes with life times actual for period more than 100 000 years after incident. If we talk about periods comparable with our time scale, the list of isotopes is rather big, e.g. for melting of a nuclear reactor core isotopes actual for long period of time are likely:
H-3, Sr-89, Sr-90, Y-91, Nb-93m, Nb-95, Ru-103, Ru-106, Ag-110m, Cd-113m, Cd-115m, Sn-121m, Sn-123, Sb-124, Sb-125, I-129, Cs-134, Cs-137, Ce-141, Ce-144, Pm-147, Tb-160, Pu-238, Pu-239, Pu-240, Am-241, Pu-241, Cm-242, Pu-242, Am-243, Cm-244 (the list was borrowed from a document published even before Fukushima and illustrates level of the problem).
