During operation, structural components made of zirconium alloys are subject to neutron irradiation, which leads to the displacement of zirconium atoms from their lattice sites, the production of self-interstitials and vacancies, and eventually dislocation loops. This process can lead to deleterious effects such as irradiation growth, creep and embrittlement as well as accelerated aqueous corrosion.

Quantitative analysis of dislocation line densities is seen as an important pathway to distinguish between the irradiation response of different alloys. Analysis of irradiation damage using x-ray diffraction (XRD) line profile analysis has proven to be a powerful complementary technique to transmission electron microscope (TEM), which samples a comparatively large volume and is less affected by the subjectivity of image analysis.

In the present work, we present 3 different types of x-ray diffraction experiments and their analysis, describe their purpose and the new insight achieved using such techniques. First, we present work carried out on neutron irradiated samples, comparing dislocation line densities measured by XRD with macroscopic growth measurements. Here we demonstrate a correlation between <c>-loop dislocation density and irradiation induced growth strain. A second experiment using a synchrotron-based x-ray microbeam enabled the mapping of dislocation line densities as a function of depth from the surface of proton irradiated Zr-alloys. These data are compared with calculated damage profiles providing new insight in possible early saturation of damage. Finally, the last example presented here focuses on synchrotron-based 3D-XRD measurements where dislocation loop line densities were analysed in hundreds of individual grains providing excellent statistics about the grain-to-grain variability of line densities.