Fractal analysis of pore structure of IG-110 nuclear graphite using X-ray micro-CT

In this work, the 3D pore structure of pristine and oxidized IG-110 nuclear graphite was studied using X-ray micro-Computed Tomography (XCT). The results revealed a nonuniform oxidation profile in the bulk sample at 650 °C. A comprehensive methodology was developed to quantitatively characterize the complex pore structure, incorporating analysis of pore size distribution, morphology, fractal characteristics and two-point autocorrelation function based on the CT images. The findings demonstrated that both porosity and fractal dimension increased after oxidation. Furthermore, 2D image analysis provided a depth-dependent characterization of the oxidation profile highlighting significant variations in the surface and internal regions. The results underscore the potential of fractality as a comprehensive measure of porosity and structure inhomogeneity, offering additional parameters for a more quantitative description of the nuclear graphite microstructure.