The integral fast reactor (IFR, originally advanced liquid-metal reactor) is a design for a nuclear reactor using fast neutrons and no neutron moderator (a "fast" reactor). IFR would breed more fuel and is distinguished by a nuclear fuel cycle that uses reprocessing via electrorefining at the reactor site. The proposed Generation IV Sodium-Cooled Fast Reactor is its closest surviving fast breeder reactor design. Other countries have also designed and operated fast reactors.