In-situ observation of Hydrogen diffusion in zirconium alloys

Zr is used extensively in nuclear reactors worldwide in a broad range of microstructural conditions due to its thermomechanical, corrosion and neutronic properties. However the affinity between H and Zr leaves Zr-alloys susceptible to precipitation of Zr hydride and delayed hydride cracking (DHC); a process controlled by the diffusion of H. The purpose of this work is to characterize the effect of the anisotropy of the Zr hcp lattice and the morphology of the beta-Zr phase on H mobility. Building on past experience, where we have refined a method to determine H diffusion coefficients using relatively small samples and short experimental times, we propose to follow the process of H diffusion in-situ, at operation temperatures of nuclear components (280C-350C), to better understand the anisotropy observed in H diffusion along the radial and axial directions of pressure tubes.