| High-Temperature Fracture Strength of a CVD-SiC Coating Layer for TRISO Nuclear Fuel Particles by a Micro-Tensile Test |
| Hyun Min Lee, Kwi-Il Park, Ji-Yeon Park1, Weon-Ju Kim1, Do Kyung Kim |
Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST)
1Nuclear Materials Research Division, Korea Atomic Energy Research Institute (KAERI) |
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| ABSTRACT |
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Silicon carbide (SiC) coatings for tri-isotropic (TRISO) nuclear fuel particles were fabricated using a chemical vapor deposition (CVD) process onto graphite. A micro-tensile-testing system was developed for the mechanical characterization of SiC coatings at high temperatures. The fracture strength of the SiC coatings was characterized by the developed micro-tensile test in the range of $25^{circ}C$ to $1000^{circ}C$. Two types of CVD-SiC films were prepared for the micro-tensile test. SiC-A exhibited a large grain size (0.4 ~ 0.6 m) and the [111] preferred orientation, while SiC-B had a small grain size (0.2 ~ 0.3 mm) and the [220] preferred orientation. Free silicon (Si) was co-deposited onto SiC-B, and stacking faults also existed in the SiC-B structure. The fracture strengths of the CVD-SiC coatings, as measured by the high-temperature micro-tensile test, decreased with the testing temperature. The high-temperature fracture strengths of CVD-SiC coatings were related to the microstructure and defects of the CVD-SiC coatings. |
| Key words:
SiC coating layer, TRISO, Micro-tensile-test, High temperature fracture strength, Weibull statistics |
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