> But the fuel cost of thorium is an order of magnitude below uranium due to no enrichment This turns out not to be true in practice. Uranium-238 is fertile ju

> But the fuel cost of thorium is an order of magnitude below uranium due to no enrichment This turns out not to be true in practice. Uranium-238 is fertile just like Thorium-232. To run a reactor off either of these fertile fuels requires breeder reactor technology, which involves chemical separations and exotic fluids. In practice, this has always been more expensive, even though the U-238 or Th-232 is not enriched. It turns out that breeder reactor infrastructure outweighs the cost reduction in not having to enrich. In fact, this is the primary reason that we don't have any breeder reactors today: it's simply cheaper to mine and enrich uranium than to reprocess. There are political reasons as well, but the primary reason is this economics.