Dresden 2026 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 36: Topical Session: Advanced Nanomechanics – Accelerating Materials Physics from the Bottom II

MM 36.4: Vortrag

Donnerstag, 12. März 2026, 16:45–17:00, SCH/A251

Mechanical Properties of Irradiated Zircaloy Cladding and Their Impact on Structural Integrity During Dry Interim Storage — •Tzu Yen Lin¹, Michel Herm¹, Volker Metz¹, Maria Vrellou², and Christoph Kirchlechner² — ¹Karlsruhe Institute of Technology, Institute for Nuclear Waste Disposal, P. O. Box 3640, 76021 Karlsruhe, Germany — ²Karlsruhe Institute of Technology, Institute for Applied Materials, P. O. Box 3640, 76021 Karlsruhe, Germany

In Germany, spent nuclear fuel is planned for disposal in a deep geological repository after 2050. The SNF assemblies are stored in dual-purpose casks, while delays in repository commissioning may extend storage beyond licensed periods. Evaluating the safety of Zircaloy-4 cladding during extended dry storage requires assessing the effects of irradiation damage, hydride formation, and microstructural evolution. This work aims to establish a reliable micromechanical testing methodology for irradiated Zircaloy-4. As a precursor to irradiated samples, Electron Backscatter Diffraction (EBSD) and nanoindentation were performed on non-irradiated cladding in hydrogenated and non-hydrogenated states. EBSD revealed variations in grain size, texture, anisotropy, and dislocation density from manufacturing processes, with further increases from hydrides. Nanoindentation showed higher hardness and reduced modulus in hydride regions compared with the α-Zr matrix. Occasional pop-ins in load-displacement curves indicate dislocations or microstructural discontinuities, consistent with misorientation patterns observed in EBSD.

Keywords: Nanoindentation; Electron Backscatter Diffraction; Zircaloy-4 Cladding; Dry Interim Storage