ABSTRACT
Fast reactors are in theory able to burn all the uranium that is fed to them. Since plutonium dominates so much of the discussion of nuclear energy, discussion of general aspects of a fast reactor will start by looking at how plutonium comes into being. There are three types of fast reactors: liquid-metal fast breeder reactors (LMFBR), gas cooled fast reactors (GCFR), and molten salt breeder reactors (MSBR). The fuel for fast reactors consists of a mixed U-Pu oxide, which has been developed into a very robust and highly reliable product, fully proven for 10% burn-up. Fast reactors, with their closely packed fuel elements and operation at extremely high thermal ratings, require extraction of very large quantities of heat from small spaces. A reflector material is used in both thermal and fast reactors to reflect escaping neutrons back into the core.
