High Temperature Materials for the Gas-Cooled Fast Reactor

Participants: G. S. Was, PI; G. Gupta, Graduate Student
SponsorIdaho National Laboratory

Both France and the United States have a shared interest in the development of advanced reactor systems that employ inert gas as a coolant. Currently, insufficient physical property data exist to qualify candidate materials for gas-cooled fast reactor (GFR) designs. The overall goal of the GFR materials qualification program is to establish candidate metallic and ceramic materials for GFR designs and to evaluate the mechanical properties, dimensional stability, and corrosion resistance.

As part of the GFR evaluation of metallic components, a study is underway to determine if grain boundary engineering techniques can improve the high temperature creep strength of candidate metals by optimizing grain boundary structural orientations. As part of this study, the focus of our work is in the following areas: 1) grain boundary engineering of T91 and HT-9, 2) tests to understand the thermal stability of treatments developed to optimize the grain boundary structure of T91, 3) creep testing of alloy T91 in both the as-received and optimized conditions, 4) characterization of the microstructure in the as-received, aged, crept and optimized alloy T91, and 5) grain boundary engineering of nickel-base alloy 617.