Molten Salt reactors are great at recycling spent uranium and don’t really cause pollution. If anything they reduce pollution because they create less nuclear garbage.

If it was that big of a problem folks would be doing PUREX reprocessing with all nuclear fuel. Not a clean process, but reduces the overall mass problem you have with spent fuel rods. No matter what you do, you just can't burn off the fission products that last forever and ever. You can put them in a container the size of a coffee can that still emits a similar amount of radiation as a whole rod if you want, but I'm not sure I see the utility. They just take those and vitrify them to make them bigger to take advantage of the inverse square law and make them safer to handle.

As long as uranium stays cheap, neither reprocessing, breeders, or reactors that eat the plutonium they produce really makes sense. You still need a similar site to store the waste regardless. As it stands I don't think we'll see uranium being a significant part of running a reactor in the foreseeable future. (As long as you're not a nuclear weapons state that doesn't have a robust fuel enrichment program, like India).