Grant: Alliance Grants

SMRs are typically anticipated to have an electrical power output of less than 300 MWe (electric) or less than 1000 MWth (thermal). They offer many advantages, such as relatively small physical footprints, reduced capital investment, the ability to be sited in locations not possible for larger nuclear plants, and provisions for incremental power additions. During operation, the reactor pressure vessel material is exposed to high temperatures exceeding 1000°C, radiation, and corrosion, resulting in localized embrittlement of the vessel and welds in the reactor core. As the reactor vessel is considered irreplaceable, these demanding operating environments require the development of new alloy materials that can withstand their increased physical, chemical, thermal, and radiation-related challenges, as well as computational approaches to predict their behavior under operation conditions. High Entropy Alloys (HEAs) are a promising option, due to their composition which can be tuned over a wide range of possibilities to optimize high-temperature mechanical properties, radiation, and corrosion resistance, and obtain improved performances compared to conventional materials. However, current knowledge of HEAs properties is still less advanced compared with conventional alloys, and further studies are needed to assess the opportunities they offer. Refractory HEAs (RHEAs) are of particular interest to the nuclear community due to their retention of mechanical properties at high temperatures, reduced defect production, and resistance to irradiation-induced swelling and hardening. However, the mechanism behind these observations is still not well understood because of the lack of computational. In this regard, the proposed research activity will develop a Phase Field Crystal (PFC) model for HEAs to understand their properties as well as environmental degradation mechanisms. In addition to the design of new materials for the body of the SMRS vessel, our result will provide valuable information that can improve the reliability of systems, structures, and components during normal, abnormal, and long-term operations.