Linking Lattice Strain and Fractal Dimensions to Non-monotonic Volume Changes in Irradiated Nuclear Graphite

Abstract

Graphite's resilience to high temperatures and neutron damage makes it vital for nuclear reactors, yet irradiation alters its microstructure, degrading key properties. We used small- and wide-angle X-ray scattering to study neutron-irradiated fine-grain nuclear graphite (Grade G347A) across varied temperatures and fluences. Results show significant shifts in internal strain and porosity, correlating with radiation-induced volume changes. Notably, porosity volume distribution (fractal dimensions) follows non-monotonic volume changes, suggesting a link to the Weibull distribution of fracture stress.

Keywords

fractal dimensions / nuclear graphite / radiation damage / X-ray scattering

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RIGHTS & PERMISSIONS

Published 2025. This article is a U.S. Government work and is in the public domain in the USA.