It's pretty old news, yes. iirc, it made the news around 2010 or so.
Pretty elegant concept, developed and abandoned in the 50s or so in the US.
Some of them use Thorium as fuel, which is much more abundant than Uranium, and leaves nearly no nuclear waste. Nuclear waste from conventional reactors can also be used/added as fuel, if I am not mistaken.
Much safer too, as salt mixed with fuel becomes solid when reactor is switched off/loses power, thus interrupting the fueling cycle.
China, in the meantime has built at least one and is said to have a large scale commercial version running by 2030
https://www.globalconstructionreview.com/china-unveil-worlds-first-waterless-molten-salt-re/