9 - Irradiation-resistant ferritic and martensitic steels as core materials for Generation IV nuclear reactors

Abstract

Ferritic-martensitic (FM) steels have many advantageous properties for use as the core components of future Generation IV reactors. They have excellent void swelling resistance and maintain their mechanical properties (e.g., toughness, tensile properties, and creep resistance) to high doses for irradiation at temperatures of 400–550ºC. The main weakness of FM steels regarding their performance under irradiation is their pronounced hardening and embrittlement when they are irradiated at low temperatures. This can present an issue for advanced systems that operate at low temperatures, such as fusion reactors or accelerator-driven systems (e.g., MYRRHA), but is less of an issue for sodium-cooled fast reactors and lead-cooled fast reactors. In addition, conventional 9–12 Cr FM steels have limited high-temperature applications above 550ºC because of reduced strength and creep resistance but advanced FM steels or FM oxide dispersion-strengthened steel may be an alternative for use at elevated temperatures.