Education and Training Series #65: Development of Nanosized Carbide Dispersed Advanced Radiation Resistant Austenitic Stainless Steels (ARES) for Generation IV Systems

These webinars, organised by the GIF Education and Training Working Group are streamed live monthly. The recordings and slide decks are accessible after the webinar on this website. These webinars cover a very broad range of technical and policy related topics. At the end of 2023 they have been viewed by more than 15000 people (approximately half of the views during the live streams and the other half views being of the archives on the public GIF website). In total, the GIF webinars have reached Generation IV enthusiasts, scientists, and engineers in more than 80 countries.

These webinars are organised and hosted by the GIF Education and Training Working Group (ETWG). 

Austenitic stainless steels are widely used as in-core materials in current nuclear systems, due to a combination of corrosion resistance, ductility, and other mechanical properties. However, in the next generation nuclear systems that will be operated at higher temperature and higher level of neutron irradiation, the use of austenitic stainless steels is largely avoided mostly due to poor void swelling resistance. In this regard, our research group developed an austenitic SS with uniformly distributed nanosized NbC precipitates, named as ARES-6P, by controlling chemical composition and thermo-mechanical processing. To demonstrate the radiation resistance, heavy ion irradiation was performed at high temperatures to the damage level of ~200 displacement per atom (dpa). The measured void swelling of ARES-6P was 2‒3%, which was considerably less compared to commercial 316 stainless steel and comparable to ferritic martensitic steels. In addition, the increment of hardness measured by nano-indentation was much smaller for ARES-6P compared to 316 stainless steel. Though some nanosized NbC precipitates were dissociated under relatively high dose rate (~5.0 × 10-4 dpa s-1 ), a sufficient number of NbC precipitates remained to act as sink sites for the point defects, resulting in superior radiation resistance. Both significantly less void swelling and less irradiation hardening indicate the superior irradiation resistance of ARES-6P for the application of next generation nuclear systems.