Breeder reactor#The fast breeder reactor

A liquid metal cooled fast breeder reactor, LMFBR also because of the English name Liquid Metal Fast Breeder Reactor, is a type of nuclear reactor.

The term " fast breeder reactor" expresses that the reactor, the nuclear chain reaction maintains by fast neutrons and fast neutrons by uranium 238 into plutonium converts (usual parlance bred ). The non-fissionable uranium -238 isotope is converted by capture of a neutron in uranium -239 and then a beta decay in neptunium -239, also arises from the beta decay of plutonium -239. The latter is a fissile isotope, and contributes to the continuation of the chain reaction in the nuclear reactor at.

The reactor uses a liquid metal, which does not slow down neutrons, as a heat exchanger. Suitable metals are sodium, mercury, lead or an alloy of sodium and potassium ( NaK ).

A lead- bismuth alloy was used in the Soviet Union as a coolant for nuclear reactors. Although this alloy is more effective than a conventional pressurized water cooling, but also accordingly difficult to handle. The alloy is solidified at a temperature below 125 ° C, thereby causing large damage the reactor. Such reactors have been used, among others, on submarines ( eg U - boat of the Alfa- class)

• Type of reactor