What is a molten-salt or thorium reactor?

Molten-salt reactors dissolve their fuel in a liquid salt, so they run at near-atmospheric pressure, can be refuelled while operating, and lean on inherent safety features like a freeze plug that drains the core if power is lost. The thorium version (LFTR) would breed fuel from an element three times more abundant than uranium. It's one of the most exciting ideas in the field.

The history is real — Oak Ridge ran a molten-salt test reactor from 1965 to 1969 — and companies like Kairos, Terrestrial Energy and ThorCon are reviving it. We flag this as advocacy because confident 'cheaper than coal' claims aren't yet demonstrated commercially. But the potential is large, and the renewed engineering effort is well earned.