The fast breeder is a type of nuclear reactor without a moderator, designed to produce more fissile material than it consumes.
A fast breeder reactor used for power generation is known as an FBR. FBRs have been built and operated in the USA, France, the former USSR, Japan, and as of 2003 one was planned for India, and another for China using Soviet technology. One in the USSR was also previously used for desalination. South Korea is developing a design for a standardised modular FBR for export, to complement the standardised PWR and CANDU designs they have already developed and built, but has not yet committed to building a prototype.
An experimental FBR in Germany was built but never operated. Two experimental fast power reactors were also built in Scotland but are now decomissioned.
An experimental FBR (FBTR) is commissioned in Jan 98 in India and is in operation
Fast reactors typically use liquid metal cooling. Lead, NaK and sodium have all been used successfully. All FBRs to date have used sodium.
To date, all fast breeders have also relied on plutonium in the initial fuel charge, and have then produced more plutonium by irradiation of non-fissile uranium-238. This system, known as the plutonium economy, was for a time believed to be the future of nuclear power. It remains the strategic direction of the power program of Japan. However cheap supplies of uranium and especially of enriched uranium have made current FBR technology uncompetitive with PWR and other thermal power reactor designs. PWR designs remain the most common existing power reactor type and also represent most current proposals for new nuclear power stations
It is generally agreed that the FBR poses a greater risk of proliferation of nuclear weapons than the PWR. Unlike a PWR, an FBR can in theory produce weapons grade material. However, to date all known weapons programs have used far more easily built thermal reactors to produce plutonium.
The FBR program of India includes the concept of using thorium to breed fissile uranium-233. In theory, it is also possible to use thorium to operate a thermal breeder reactor. This is not possible with purely uranium/plutonium based technology. Thorium fuel is the strategic direction of the power program of India.
One design of a power reactor, specifically designed to address the waste disposal and plutonium issues, was the Integral Fast Breeder Reactor (a.k.a. Integral Fast Reactor)class="external">[1. Being a "breeder" it was designed to be fueled ONCE, then produce all its own fuel during operation. To solve the waste disposal problem, it had an on site electrorefining fuel reprocessing unit that recycled the uranium and all the transuranics (not just plutonium) via electroplating, leaving just short half-life fission products in the waste. Some of these fission products could later be separated for industrial or medical uses and the rest sent to a waste repository (where they would not have to be stored for anywhere near as long as wastes containing long half-life transuranics). It would NOT be possible to divert fuel from this reactor to make bombs, as several of the transuranics spontaniously fission rapidly enough that any assembly would simply melt before it could be completed. The project was canceled in the late 1980s after all elements of the system had been tested, but before engineering designs could be completed for an operational power plant.
As of 2001, two fast breeders remained in operation worldwide, neither of which was in the United States. These were Phenix in France and Monju in Japan. Phenix is currently the centre of work on destruction of nuclear waste by transmutation.