Nickel-free austenitic stainless steel alloys as a sodium-cooled fast reactor fuel cladding

Abstract

ABSTRACT Nickel-free austenitic stainless steel alloys Fe-Cr-Mn (SSMn) and Fe-Cr-Mn-N (SSMnN) were successfully developed to be used as sodium-cooled fast reactor fuel cladding. An austenite phase was observed through microstructure examination for both SSMn and SSMnN. The effect of Mn and Mn-N as an alternative to Ni on tensile properties was studied at room temperature. Subsequently, the effect of temperature was studied through tensile testing of the alloys produced at 300 ºC and 500 ºC. Mn and Mn-N enhance the room temperature yield strength (YS) and ultimate tensile strength (UTS). Mn caused a small reduction in elongation (El%) but Mn-N caused its deterioration. The YS, UTS, and El% of both SSMn and SSMnN alloys are strongly temperature dependent. Both the SSMn and SSMnN alloys showed better mechanical properties than the standard AISI304 at elevated temperatures. So, the SSMn and SSMnN alloys could be considered strong candidates as fuel cladding for sodium-cooled fast reactors.