I grew up a few miles from the OAK Ridge National Laboratory. My father worked for the NRC for a while as well. The molten salt reactors are fabulously safe, BUTTTT they aren't breeding reactors. That is the big hang-up in it's adoption. By a far margin, most reactors in the world are breeder reactors meaning you can make other isotopes with them, chiefly plutonium for nuclear bombs and enriched fuels, as well as radio active medical and industrial products. Yet once you have a couple of those running, you don't need more of them, but it becomes harder to sell the new designs to the bean counters who expect all of these other products to compensate for the cost even if that capacity won't really be used.
