Nuclear energy currently provides around 20% of the nation's energy. The current mainstream nuclear reactor designs (mainly Pressurized Water Reactors) use fuel inefficiently, and produce significant quantities of long-lasting radioactive waste, and some that is capable of being used to produce nuclear weapons. LFTRs are based on much safer, very efficient designs, and produce less waste - the waste that is produced is much shorter lived and almost entirely not usable for nuclear weapons. The main fuel (thorium) is also much more plentiful and easily available.
Construction of LFTRs could sate America's growing hunger for electricity while also making its energy source safer.