Materials development for the ARC fusion power plant

Abstract: Commonwealth Fusion Systems (CFS) is developing the ARC fusion power plant, which features a liquid salt breeding blanket and a replaceable integration vacuum vessel and plasma-facing material. CFS is undertaking a multifaceted material development roadmap to design materials that will be ready for the first ARC deployment in the early 2030s. The liquid FLiBe blanket, motivates a desired steady-state temperature operating range of approximately 600-850°C for the structural materials of the vacuum vessel and blanket tank. Thus, these components must withstand significant heat and neutron flux while operating at elevated temperatures in a potentially corrosive environment.  ARC’s architecture is designed such that this integrated vessel will be replaced over a plant’s operating lifetime, enabling utilization past the point where materials experiencing the harshest conditions will be significantly degraded. Therefore, with ARC operating in a temperature regime where few materials are viable and there are significant gaps in the existing irradiation data, CFS has developed a roadmap of material development that utilizes fission irradiations, ion irradiations, and modeling to reduce risk for ARC operation. Additional challenges and opportunities exist for materials and processing innovation across systems required for high-field tokamak operation including optimized, large-format deep cryogenic steel production for magnet structures and high efficiency welding operations for cryogenic service among others.

Bio: Cody A. Dennett is the Director of Materials Technology at Commonwealth Fusion Systems. The Materials Department at CFS supports design engineers, supply chain, and manufacturing by selecting materials, validating those materials and their properties, and conducting R&D to develop new materials and processes for SPARC and future ARC fusion power plants. Cody joined CFS in 2022 and has grown Materials at CFS from a staff one to now 45 engineers and test operators. Prior to CFS, Cody was a distinguished postdoctoral fellow and staff materials scientist in the condensed matter and materials physics group at Idaho National Laboratory and received his PhD from MIT in nuclear materials science.