LWR technology is limited by steam’s low heat transfer capacity, and the pressure needed to keep very hot water a liquid; much of the expense of LWR is high-pressure pipes, safety systems to prevent pressure explosions or loss of coolant when pipes break, and the huge steam containment building, which obviously is for containing high-pressure 350ºC water if a pipe breaks.
(At Fukushima, the reactors were shut down properly before the tsunami struck. Fukushima reactor core damage, hydrogen buildup, and radiation leakage was from loss of water coolant, after losing power to the cooling systems.)
LFTRs have no water in the reactor. In all types of Molten Salt Reactor, the fuel is dissolved in molten salt and transfers heat (via heat transfer units without any radioactive materials) out of the reactor. The fuel salt remains liquid, even at temperatures much higher than the reactor can ever get, at atmospheric pressure.
LFTRs can be installed even in deserts. LFTRs can be located in small sites wherever needed, or even transported for military or disaster relief use.
Use reactor heat for generating electricity and other industrial processes, such as desalinating water or making gasoline from carbon dioxide and water. Transfer any unused heat to air or water.
If water got in the reactor (e.g. a tsunami or hurricane), it would simply boil away. Nothing in any type of Molten Salt Reactor chemically reacts with water or dissolves in water, and all transuranic elements are strongly chemically bound to the fluoride salts. If there was structural damage, passive safety systems would simply dump the fuel into passive cooling tanks. (Later re-heat and pump fuel back into the reactor.)