A Sodium-cooled Fast Reactor (SFR) is a type of nuclear reactor that uses liquid sodium as a coolant. This design allows for efficient heat transfer and enables the reactor to operate at higher temperatures compared to traditional water-cooled reactors. SFRs utilize fast neutrons to sustain the nuclear fission process, which can improve fuel efficiency and reduce nuclear waste. SFRs are part of the broader category of fast neutron reactors, which can utilize a variety of fuels, including plutonium and uranium. They are considered a promising technology for advanced nuclear power systems, contributing to sustainable energy solutions and the potential for nuclear fuel recycling.