Morphological analysis of zirconium nuclear fuel retaining rods braided with SiC: Quality assurance and defect identification

[Display omitted] •The stability of materials under extreme conditions is an important issue for the safety of nuclear reactors.•To improve zircaloys’ thermal stability in off-normal conditions, coating of SiC filaments is considered because silicon carbide possesses remarkable inertness at high temperatures.•Mathematical morphology was used for automatic defect identification in Zircaloy-4 rods braided with the layer of SiC filament.•The original mathematical morphology algorithms allowing solving the problem of quality assurance were developed.•In nuclear industry, such algorithms are used for the first time. In the after-Fukushima world, the stability of materials under extreme conditions is an important issue for the safety of nuclear reactors. Among the methods explored currently to improve zircaloys’ thermal stability in off-normal conditions, using a protective coat of the SiC filaments is considered because silicon carbide is well known for its remarkable chemical inertness at high temperatures. A typical SiC fiber contains ∼50,000 individual filaments of 5–10μm in diameter. In this paper, an effort was made to develop and apply mathematical morphology to the process of automatic defect identification in Zircaloy-4 rods braided with the protective layer of the silicon carbide filament. However, the issues of the braiding quality have to be addressed to ensure its full protective potential. We present the original mathematical morphology algorithms that allow solving this problem of quality assurance successfully. In nuclear industry, such algorithms are used for the first time, and could be easily generalized to the case of automated continuous monitoring for defect identification in the future.