X-ray characterization of atomistic defects causing irradiation creep of SIC

Technical Report · Mon Oct 01 04:00:00 EDT 2018

DOI:https://doi.org/10.2172/1495974· OSTI ID:1495974

Koyanagi, Takaaki ^[1]; Kato, Yutai ^[1]

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1. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

Silicon carbide (SiC) fiber–reinforced SiC matrix composites have been widely studied for use in developing an accident-tolerant fuel (ATF) cladding for light water reactors (LWRs) in recent years because of their superior oxidation and irradiation resistance and low neutron absorption cross section. An important task is the establishment of the thermo-mechanical analysis capability to predict the in-pile performance and failure probability of the cladding. Irradiation creep is known to be a key property in modeling the stress state under irradiation. To better understand the radiation creep mechanism from an atomic point of view, this study conducted synchrotron-based X-ray diffraction (XRD) experiments on SiC neutron-irradiated with and without applied stress at the National Synchrotron Light Source-II (NSLS-II). This report presents progress of the XRD study and future plans. The important finding obtained was that the macroscopic creep strain and strain due to the lattice expansion were similar in case of neutron irradiation at 300°C to 0.1 displacement per atom (dpa), which indicates that the lattice strain is a major source of the transient creep strain.

• Research Organization: Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-00OR22725
• OSTI ID: 1495974
• Report Number(s): ORNL/SPR-2018/1031
• Country of Publication: United States
• Language: English

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36 MATERIALS SCIENCE