The other issue is building a new reactor of any type right now is a giant pain in the ass, which doesn't help either.
LWRs are resupplied every year with expensive fabricated fuel rods, which are non-standard and can only be purchased from the company that sold the reactor. The fuel rods are complicated because they have to withstand a thousand-degree temperature gradient, and the fuel pellets are prone to cracking from the production of xenon gas. Xenon and other reaction products prevent the use of more than one percent or so of the energy potential of the nuclear fuel, another reason the rods are frequently replaced, and the reason we have so much nasty nuclear waste.
The nuclear industry makes most of its revenue from selling those fuel rods.
LFTRs operate at atmospheric pressure. No super-strong steel, no containment dome, no ice. It's a liquid fuel, so no proprietary fuel rods. Xenon just bubbles out of it.
The fuel has a strong "negative coefficient," meaning the reaction slows down as it gets hotter. If it nevertheless gets too hot, a salt plug melts and all the fuel drains into a passive cooling tank. No need for all those active cooling systems.
On top of that, LFTRs operate at higher temperature, so the turbine is more efficient, and the waste heat can be used to desalinate seawater. They don't require water cooling. As a bonus, marketable reaction products can be separated from the liquid fuel (http://flibe-energy.com/products/).
Misguided government regulation is the main problem, but Sorenson's company plans to get around that by selling to the military first.
Sorry but is this subtle irony? My apologies if it's not, I don't know anything about this field. It just seems weird that the military wouldn't be subject to the same regulations that the govt. sets? Or in the US are the military able to ignore some of the regulations around this?
The reason that anything new is a pain in the ass is simply because of bureaucracy.
Sorenson's company plans to market initially to the military, which has need of compact energy sources for remote bases and isn't constrained by the NRC.
It's sort of like inkjet printers. Either it's cheaper up front and more expensive in the long run, or it costs a fortune up front but the ink is cheap.