This is totally bull shit.
While it`s true that the "once through" reactors create spent control rods that have beta decay of millions of years, the fast reactors design is to take those rods and fuel it`self and a few more reactors and reduce spent control rods to have a beta decay of less than 200 years. This is very manageable. As to the fizzle properties of the rods, you can use them to produce weapons grade materials, but not after they have gone through the second time. So it is possible to take a few rods and hide them til you acquire enough to build a bomb in secret. (why I don`t trust Iran)
So tity, tell me how horrible and highly radioactive a spent control rod who`s decay is rendered harmless after only a few (200+/-50) short years ? Fossile fuels` carbon footprint lasts much longer. Thermonuclear,....don`t even have one.
So as long as you don`t break them,.... they are safe and as green as a clover and,.. after two hundred or so years, the spent rods can be reused to soak up more glowing shit again....go through a fast reactor, get stored, reused,...so on.... Break them,...well the best thing for the general public would be Natural,...Run , run far and fast...just don`t go around the world and come back to it...