Even if thorium reactors could be built right now and use waste from older reactors, there is still the process of mining and handling radioactive material.
Nuclear may be preferable to coal but (IMO) not to large scale development of solar, wind, and higher efficiency grids.
We only need to mine 1/1e6'th of it compared to conventional chemistry. Thorium is a waste product, we mine it anyway, it's with the Lanthanides. It's an alpha emitter so unless you ingest it (serious hazard, dont ingest alpha emitters) it's not difficult to work with.
Nuclear may be preferable to coal but (IMO) not to large scale development of solar, wind, and higher efficiency grids.