b'Hermeticity Evaluation of SiC/SiC Composite TubesRelevant to LWR Cladding ApplicationPrincipal Investigator: Xunxiang Hu, ORNL Collaborators: Takaaki Koyanagi and Yutai Katoh (ORNL)Figure 1. a) Permeation testing systemC ontinuous SiC fiberreinforcedProject Description:at LAMDA. b) A tubular SiC/SiCSiC matrix ceramic (SiC/SiC)The project goal is to establish an composite tube mounted to a stainlesscomposites are perceived as oneexperimental capability for measuring steel sample fixture using epoxy.of the leading candidate materials forthe gas permeation flux through accident-tolerant fuel cladding in lightSiC/SiC composite tubes under water reactors (LWRs). Potential lossunirradiated and irradiated conditions of containment of the fission productsas a function of gas pressure at room The hermeticity of SiC/ due to penetrating cracking has beentemperature. The major challenges SiC composite tubesidentified as one of the most criticalassociated with testing tubular subject to LWR-relevanttechnical issues for SiC-based nuclearsamples involve sealing the open ends environments wasfuel cladding. Therefore, evaluation ofof tubular samples and achieving evaluated using the high- the hermeticity of SiC/SiC compositeacceptable leakage rate resolution in resolution permeationcladdings subject to LWR-relevanttesting lab-scale tubular samples. This testing station at ORNL. environments is critically important.project is developing a high-resolution Gas permeation flux throughpermeation testing system for the SiC-based cladding is considered anhermeticity evaluation of SiC/SiC important indicator for evaluating thecomposite tubes. The expected project hermeticity of the studied materials.output is measurement of the gas However, gas permeation data for SiCpermeation flux in SiC/SiC composite and SiC/SiC composites in tubulartubes subject to LWR-relevant configurations are very limited,environments by employing the especially for samples subjected todeveloped permeation testing system.neutron irradiation.84 2019|AFC ACCOMPLISHMENTS'