Optical Microscopy

Microstructural characterization of nuclear graphite provides insight into the constituent phases (filler, binder, and void content) and material features across multiple length scales. This understanding supports interpretation of bulk mechanical, thermal, and physical property measurements, irradiation response, and predictive models used in reactor design and safety analysis. Specimens relevant to the AGC irradiation experiments and historical graphite grades are examined using a suite of complementary microscopy techniques: Optical Microscopy characterizes porosity and grain structure to establish a baseline to identify pore size distribution and grain size. X-ray Computed Tomography (XCT) enables non-destructive, three-dimensional imaging of the internal pore network and its spatial distribution. Scanning Electron Microscopy (SEM) provides high-resolution imaging of surfaces and fracture faces to characterize filler particle texture, binder phases, and porosity within each phase.