There plenty of good things about Thorium, however the advantages are generally overstated. Yes it's more common but uranium is plentiful and a small fraction of operating costs. Yes, it produces less waste but The difference is minimal. In theory it's safer, but current designs are vary safe with a multi decade track record where Thorium's is unproven.
So, while there are benefits the ROI on a multi billion dollor Thorium R&D progect are probably negative.
> So, while there are benefits the ROI on a multi billion dollar Thorium R&D progect are probably negative.
It could be possible to rebrand Thorium and overcome many of the PR challenges of nuclear power. A solution to a substantial part of the global warming problem is indeed worth hundreds of billions.
Things that are highly radioactive stop being radioactive very quickly. Things that are lowly radioactive stay radioactive for a long time, but at low levels so you don't worry much about them. There's a middle "unsweet spot" of things that are radioactive enough to worry about but not radioactive enough that they quickly burn out.
Actinides of half-life 100-100,000 years or so. These have a compounding disadvantage in that they are alpha-emitters, hence disproportionately radiotoxic (e.g. by ingestion) compared to gamma- and beta- emitters like common fission products. Orders of magnitude disproportionate.
The theoretical advantage is huge: (this graph is from a French nuclear research lab which appears to be temporarily offline)
i started building a javascript library (nuclear.js : https://github.com/reinpk/nuclear.js) to calculate the decay chains... the problem is that short lived isotopes, which are dangerous, can decay into long-lived isotopes, but basically the decay chains are complicated. i'll do a post about that soon :)
It's complicated, high level nuclear waste can be reprocessed and it becomes cheaper to do so the longer it sit's around. Low level waste is fairly cheap to deal with. So, it's really a question of what to do with the mid level stuff and they both produce similar amounts of that.
The potential of Nuclear technology is huge, unfortunately so is the associated need for a large government intensive, multi-billion, long-term investment. That's is one of the key problems with nuclear in general having an only tangential relation with the technology itself.
Compared to an equal size total investment, broken up into multiple smaller R&D areas, the the big nuclear bet is likely at a opportunity cost disadvantage. The strategy of equivalent smaller investments in other renewable technology has multiple outlet points where private industry can take and run the results into production. Although one couldn't prove that one approach would yield better than another, my feel is that the multiple smaller bets yields earlier with the potential to scale better overall.
On the other hand, while you and I might know that today's nuclear plants are tremendously safe, they have a terrifically negative public image. In a vacuum the ROI would probably be negative, but most people want nothing to do with traditional nuclear plants and the not-in-my-backyard problem is huge. If you include getting a blank slate public relations-wise, the ROI might become positive. Engineers are loathe to worry about these kinds of things, but in practice they matter quite a bit.
So, while there are benefits the ROI on a multi billion dollor Thorium R&D progect are probably negative.