IMO any reactor using thorium as a fuel is just a pipe dream;...

IMO any reactor using thorium as a fuel is just a pipe dream; however the prospects of mixed Thorium/HALEU fuels may have some legs (but probably only in Candu reactors/

The poblem is that Thorium is NOT fissile (it's only fertile) which means that it cannot be used directly as a fuel but can (if bombarded with neutrons) be transmuted into Protactinium (atomic number 91) which after a half life of around 27 days decays into 233U which is very fissile - i.e about 4kg produces a critical mass (weapon) and this weapons material only requires a simple "gun type" mechanism (this mechanism was used in the Hiroshima weapon without testing - it was so simple (the New Mexico test/Nagasaki weapons were Pu which required a much more complex implosion mechanism (which would probably defeat terrorist). The transmuted thorium cannot be left in the reactor to decay since it would then transmute to 234U (which is a nuclear poison) - it has to be chemically separated out of the fuel to decay outside of the reactor and then the fed back into the reactor as 233U. The problem is that 233U would be separated outside of the reactor and thus potentially a proliferation issue. IMO most countries would allow this to happen outside of the military (i.e not commercial operations). There are also other problems in generation of 232U which decays rapidly to 208Th which emits high energy gamma radiation which needs special "hot cells" to handle it.
There are other considerations like little experience and therefore large research/development expenditure (and about 20 years of testing) before a commercial product

IMO - almost no prospect in the foreseeable future (mixed Th/Haleu fuel (ANEEL) are however currently under test for Candu reactors (see HERE) - these never leave the reactor but it's the HALEU (not the Th) which makes them to fissionable (it sort of acts like a "wick" in a candle) which then transmute to 233U in the mixed fuel element (after it's spent it's then discarded as HL waste - separated 233U never sees the light of day outside of the reactor core)