Sodium Cooled Fast Neutron Breeder Reactors
Advanced Gen-IV SFR Reactors
The SFR constitutes a breeder reactor, which means it uses fast neutrons to generate more fissile material than it consumes because its neutron economy is high enough to breed fissile fuel from fertile material. In this way the nuclear fuel cycle can be almost closed and much less waste with even less radioactivity (decay within centuries) may be generated.
Sodium-cooled fast reactors are the most promising type of reactors to achieve Generation IV nuclear reactor goals at a reasonable time scale given the accumulated experience over the years.
SFR uses liquid sodium as the primary coolant. As one of the six Gen-IV nuclear reactor systems, SFR has become the "first seed" in the world due to its great breeder characteristics and the richest construction and operation experience, as compared with the other Gen-IV systems. SFR is built on Russia's 390 reactor-year experience with sodium-cooled fast neutron reactors, starting with the BN-350, BN-600 and BN-800 over five decades.
The Russian SFR BN-800 is not only the basis for development of a closed nuclear fuel cycle. It is also a test case for technical solutions that will later be used for commercial production of the BN-1200. The BN-800 does not have a breeding blanket and breeding ratio is quoted as 1.0, though the version designed for Sanming in China has up to 198 DU fuel elements in a blanket. In May 2009 St Petersburg Atomenergopoekt (SPb AEP, now Atomproekt) started design work on the two Chinese Demonstration Fast Reactors (CDFRs). They would use pelletized Mixed oxide (MOX) fuel, initially supplied by Russia's Mining & Chemical Combine (MCC).
China and Russia are both expanding their nuclear energy sectors, with already established links, including for the supply of fuel from Russia for the CFR-600 sodium-cooled pool-type fast-neutron nuclear reactor at Xiapu in China's Fujian province. China started operation of its first CFR-600 breeder reactor in 2023. The construction of a second CFR-600 reactor at the same site started in 2020. This unit is expected to become operational in 2026. According to the inter-governmental agreement between Russia and China signed in June 2018, Russia will supply fuel for China's CFR-600 reactor during its entire life cycle. A commercial-scale unit - the CFR1000 - will have a capacity of 1000-1200 MWe. Subject to a decision to proceed, construction could start in December 2028, with operation from about 2034.
The USA's Experimental Breeder Reactor-II (EBR-II) was a sodium-cooled fast reactor designed, built and operated by Argonne National Laboratory. Initial operations began in July 1964 and it achieved criticality in 1965. It was shut down in 1994. The original emphasis in the design and operation of EBR-II was to demonstrate a complete breeder-reactor power plant with on-site reprocessing of solid metallic fuel. Fuel elements enriched to about 67% uranium-235 were sealed in stainless steel tubes and removed when they reached about 65% enrichment. The tubes were unsealed and reprocessed to remove neutron poisons, mixed with fresh U-235 to increase enrichment, and placed back in the reactor. In 1994, the U.S. Senate, following the lead of Senator John F. Kerry and President Bill Clinton, decided to eliminate all funds for operations and research associated with the Integral Fast Reactor (IFR) project. The vote was close, only 52 senators, a small majority, voted in favor of removing the funds. That ended the EBR-II advanced nuclear power plant and closed nuclear fuel recycle project. During President Clinton's 1994 State of the Union address, he had characterized the valuable research being conducted on advanced nuclear energy systems as an unnecessary waste of money that should be stopped as part of a program of spending reductions. Russia and China recognised the massive ERoEI Society offered by the Sodium Cooled Fast Neutron Reactor and carried on with their own development work.
Currently the USA is developing in partnership with Bill Gates a Gen-IV Sodium Cooled Fast Neutron Nuclear Power Plant. The demonstration plant will be home to TerraPower's Natrium nuclear reactor. The project is slated for completion in 2030, when it will become a full-scale commercial plant. The reactor based on the Gen-IV GE-Hitachi PRISM design will produce 345 megawatts and can have its output boosted to 500 megawatts for more than five-and-a-half hours if need be. The Gen-IV GE-Hitachi PRISM design can recycle used nuclear fuel, generating electricity while reducing radiotoxicity from hundreds of thousands of years to hundreds of years