This publication presents a survey of worldwide experience gained with fast breeder reactor design, development and operation. It is focused on the following subjects: state of the art of liquid metal fast reactor (LMFR) development; design features and operating experience of demonstration and commercial sized nuclear power plants with sodium cooled fast reactors; lead–bismuth cooled (LBC) ship reactor operation experience and LBC fast power reactor development; treatment and disposal of spent sodium; decontamination after shutdown of the typical loop type LMFR; and an analysis of advantages and disadvantages of sodium as a coolant, giving due consideration to advances in the technology and design of sodium components.