b'2.4 AFC NUCLEAR ENERGY UNIVERSITY PROJECTSUniversity-Led Investigations of Behavior of SiC Composite Cladding as Accident Tolerant Fuels (ATF) for Light Water Reactors (LWRs) Principal Investigators: Peng Xu & Yutai KatoTeam Members/ Collaborators: Peter Hosemann; The Regents of the University of California, Berkeley; Christian Deck, General Atomics; Julie Tucker, Oregon State University; Djamel Kaoumi, North Carolina State University; Yongqiang Wang, Los Alamos National LaboratorySeven university-ledS iC composites are considered as aTo mitigate the corrosion of SiC promising ATF cladding materialin PWR water, the team acquired projects including 9for LWRs. The excellent neutronicSiC samples with a Physical Vapor universities, 3 nationalproperties, high strength and highDeposition (PVD) coating that consists laboratory, and 2temperature stability and oxidationof Zr, Ti, and Cr from the industry industry collaboratorsresistance make it a prime candidatepartner General Atomics, and from address key technicalfor ATF. However, because this isthe Swiss Federal Laboratory (Electron challenges andrevolutionary change to the existingProbe Micro Analysis (EPMA), Thun overcome research andzirconium alloy-based cladding, theCH). Initial characterization of the PVD development huddlesbehavior of SiC cladding under normalcoatings have been made, including for the SiC technologyoperation conditions and accidentTransmission Electron Microscopy for ATF applications. conditions need to be understand, and(TEM), diffraction, Chemi-STEM, several technical challenges shouldnanoindentation, and corrosion be addressed, such as the corrosiontests. Figure 1 shows the coating resistance and retention of hermeticity. cross section for an EPMA sample. In 2018, the Nuclear Energy UniversityIn addition to the PVD coating, the Program (NEUP) awarded 7 proposalsteam also partnered with Ionbond to study the key technical challengesand produced four Chemical Vapor SiC cladding is facing at pressurizedDeposition (CVD) coatings with water reactor (PWR) conditions as athe selected elements of TiC/TiCN, prime ATF candidate. The projects wereTiC/TiCN (optimized parameters) well coordinated, and the researchZrN, and TiN. All CVD coatings show outcomes were augmented by a closevisible defects at the surface such participation and engagement fromas cracks, pits, or delamination. The national laboratories and nuclearmicrostructure and composition of industry. All projects will finish at thethe Ionbond CVD coatings have been end of this year, after providing keyfurther investigated using Scanning technical data and insights that supportElectron Microscopy (SEM), Energy SiC development moving forward.Dispersive Spectroscopy (EDS), TEM, SIMS, and ChemiSTEM giving 98 2021|AFC ACCOMPLISHMENTS'