Generation IV reactor
Generation IV (Gen IV) reactors are nuclear reactor design technologies that are envisioned as successors of generation III reactors. The Generation IV International Forum (GIF) – an international organization that coordinates the development of generation IV reactors – specifically selected six reactor technologies as candidates for generation IV reactors. The designs target improved safety, sustainability, efficiency, and cost. The World Nuclear Association in 2015 suggested that some might enter commercial operation before 2030.
No precise definition of a Generation IV reactor exists. The term refers to nuclear reactor technologies under development as of approximately 2000, and whose designs were intended to represent 'the future shape of nuclear energy', at least at that time. The six designs selected were: the gas-cooled fast reactor (GFR), the lead-cooled fast reactor (LFR), the molten salt reactor (MSR), the sodium-cooled fast reactor (SFR), the supercritical-water-cooled reactor (SCWR) and the very high-temperature reactor (VHTR).
The majority of reactors in operation around the world are considered second generation and third generation reactor systems, as the majority of the first generation systems have been retired. Since 2021, China is the first country to operate a demonstration generation-IV reactor, the HTR-PM in Shandong province, of the pebble-bed type. (Meanwhile, Generation V reactors are purely theoretical and are not yet considered feasible.) According to Chinese state media, China began commercial operations on the HTR-PM in December 2023, which would make it the world's first Gen IV reactor to enter commercial operation.
The sodium fast reactor has received the greatest share of funding that supports demonstration facilities. Moir and Teller consider the molten-salt reactor, a less developed technology, as potentially having the greatest inherent safety of the six models.
The very-high-temperature reactor designs operate at much higher temperatures than prior generations. This allows for high temperature electrolysis or for sulfur–iodine cycle for the efficient production of hydrogen and the synthesis of carbon-neutral fuels.