Molten Salt Reactor

A molten salt reactor is a class of nuclear fission reactor in which the coolant, the nuclear fuel, or both, take the form of a molten salt mixture rather than the solid fuel rods and pressurized water used in conventional reactors. Because the fuel bearing salt is already molten, it can drain by gravity into a passively cooled containment tank if the reactor overheats, and the design runs near atmospheric pressure, at roughly 700 degrees Celsius, instead of the 75 to 150 times atmospheric pressure a light water reactor needs to keep its coolant liquid. Oak Ridge National Laboratory built the pioneering examples in the United States, the 2.5 megawatt Aircraft Reactor Experiment in the 1950s and the 7.4 megawatt Molten Salt Reactor Experiment that ran from 1965 to 1969, before the American program was set aside in the early 1970s in favor of liquid metal fast breeder research. In October 2023 China TMSR-LF1 reactor, fueled by thorium, reached criticality and went on to reach full power, becoming the first molten salt reactor to operate since the Oak Ridge experiments closed decades earlier.