"Reminds me of the scrap metal we sent to Japan before World War Two. It came back to bite us."Your analogy is actually incorrect in this case. There are various grades of spent nuclear fuel and there are ways of mixing it down with other inert binding agents to make it completely unusable for any further energy extraction, not to mention weapon manufacure purpose. So no, its not just a simple matter of "smelting it all down" like Japan did with the scrap metal and "turning out nukes". It simply doesn't work this way.
I am aware of the differences, and the difficulties of dealing with this intractable and poisonous material.
But again I refer to the interest by the Russians in what everyone else considers a dangerous nuisance substance.
Another way to look at it is that the material is a high-value, low-grade ore. Perhaps they are simply looking to the long term, when their oil and gas may no longer have the cachet that it now enjoys.
Even assuming that they are not interested in building weapons, this would provide them a great deal of fuel capability for nuclear reactors, even though the extraction process would be laborious, energy-intensive, and costly in terms of human risk. They may seek to sell reactors to others around the world, or supplement their own energy infrastructure.
In truth I applaud this possibility. But I would prefer that we were doing it. Our energy infrastructure certainly needs enhancement.