There are no technoligical peoblems. France, Japan and the UK are doing it. For power reactors, it is really a matter of economics. Uranium prices are so low now that it is cheaper to make new than to recycle the old. That could change, but that is the market now.
That does not address the issue of weapons grade stuff which never comes from or is used in a power reactor. Some sort of recycle is necessary to make it 'non weapons grade' but the Luddites won't listen to logic. Nunn -Luger was supposed buy a lot of the Russian weapons grade stuff that bin Laden & Co. have been trying to get and use a recylicing process to turn it into a power reactor fuel to eliminate it. I don't where the issue stands now, but the last I heard, the Luddites didn't want any part of it. I guess they just want it laying around so Osama or Saddam can have their chance at greatness.
Question about the "spent" fuel rods:
I know they still remain "hot" for many months when they're removed from the reactor and placed in 'temporary' holding tanks.
Is the heat that's given off in those holding tanks used for anything?
Can a reactor be designed to use the "spent" fuel-rods as-is?
(Yeah, I know it would be far less efficient than a "real" reactor.
But what the heck, heat is still heat!)