Development of in-core materials for fast breeder reactors

Abstract

Recent development of FBR fuel cladding materials is reviewed. Currently utilized advanced austenitic steels limit the neutron exposure of fuel assemblies at around 150 dpa due to swelling induced structural instabilities. The swelling is dominated by the stability of precipitates in the complex alloys during irradiation. An improvement of the austenitic steels is still possible by controlling the alloying elements such as Ti, Nb, V, P and Si, and increase in Ni content up to 25 wt% with minimal detrimental effects on high temperature creep strength. The oxide-dispersion-strengthened (ODS) ferritic steels, rather than high Ni alloys, become foreseeable by recent understanding of the mechanisms for fine oxide-particle dispersion.

Key Words:

• Materials development
• Fuel cladding
• Fast reactor
• Creep strength
• Phase stability
• Dispersion strengthening