Gas-Cooled Fast Neutron Breeder Reactor
Advanced Gen-IV GFR Reactor
The Gas-Cooled Fast Reactor (GFR) is an advanced nuclear reactor design employing a gaseous coolant, typically helium, and operating in the fast neutron spectrum. It combines the advantages of fast-spectrum systems for long-term sustainability of uranium resources usage and waste minimization (through potential multiple fuel reprocessing and the fission of long-lived actinides), with those of high-temperature systems (high thermal cycle efficiency and use of the generated heat for industrial processes requiring higher temperatures). Its inert transparent gaseous coolant brings several advantages: no corrosion at high operating temperature, very low void reactivity coefficient in case of loss of coolant, and easy visual inspection of the internals.
The GFR uses the same fuel recycling processes as the Sodium-Cooled Fast Reactor (SFR) and similar reactor technologies to the Very-High-Temperature Reactor (VHTR ). Therefore, its development approach will also benefit and support other technologies developed for other Gen IV systems, including structures, materials, components and power conversion systems.
China was the first country to operate a demonstration Modular Generation-IV reactor, the 210 MWe HTR-PM TRi-structural ISOtropic particle fuel (TRISO) (not a fast reactor) in Shidaowan, Shandong, which is a pebble-bed type high-temperature gas-cooled reactor. It was connected to the grid in December 2023, making it the world's first Gen-IV Modular Reactor to enter commercial operation.
The Japanese high-temperature engineering test reactor (HTTR) is an advanced graphite-moderated gas-cooled research reactor in Oarai Ibaraki Japan, operated by the Japan Atomic Energy Agency. It uses long hexagonal fuel assemblies, unlike the competing pebble bed reactor designs. The primary coolant is helium gas at a pressure of about 4 megapascals (580 psi), the inlet temperature of 395degC, and the outlet temperature of 850–950degC. The fuel is uranium oxide (enriched to an average of about 6%).
Following the Japanese HTTR Reactor; A design study of the hydrogen cogeneration high temperature gas cooled reactor Gen-IV GTHTR300C) that can produce both electricity and hydrogen has been carried out in Japan Atomic Energy Agency. The GTHTR300C is the system with thermal power of 600MW and reactor outlet temperature of 950degC, which is expected to supply the hydrogen to fuel cell vehicles after 2020s. In future, the full deployment of fast reactor cycle without natural uranium will demand the use of Mixed-Oxide (MOX) fuels in the GTHTR300C. Therefore, a nuclear design was performed to confirm the feasibility of the reactor core using MOX fuels. The designed reactor core has high performance and meets safety requirements.
JAEA (Japan) has successfully demonstrated the design basis for the Gen-IV GTHTR300C High Temperature Reactor through several long term research and development programs. The program has resulted in the successful operation of the high temperature HTTR 30MWt test reactor and a coolant outlet temperature of 950degC. The HTTR is currently the largest operating test reactor for the Very High Temperature (VHTR) technology in the world. It has demonstrated long-term stable operation at about 950degC with a passive reactor safety performance for the loss of coolant circulation events. In view of the above, Japan has made plans for the construction of some 120 commercial 600MWt Gen-IV High Temperature Gas Cooled Reactors (HTGR)'s (a total of 72GWt) in Japan, beginning in 2030, for use in the production of hydrogen to meet the projected demand for the nation's transportation, residential, and industry sectors and to contribute to achieve a national CO2 reduction target of 50% and 90% by the year 2050 and 2100, respectively, from the year 2000 level.