Underwriting structural steels for the sodium-cooled fast reactor

Material strength and fabrication considerations have led to the choice of AISI type 316 stainless steel for most of the components in the primary circuit and the intermediate heat exchanger for the UK fast reactor. High strength chromium-molybdenum ferritic steels are a common choice for boiler tubes and shells of the steam generator units. The physical and chemical influences of liquid sodium upon these structural steels are summarised. Laboratory techniques which have been used in investigating mechanical properties in various sodium conditions are described. Some of the results are presented and future plans for testing are discussed. (author)