The dislocation density and the composition of the β-Zr phase were determined using an X-ray diffractometer and transmission electron microscopy in irradiated Zr–2.5Nb. Through Fourier analysis of diffraction line profiles of {11▪0}, {10▪0} and {00▪1} planes, an X-ray method determined the coherent block size and the lattice strain energy, from which the a- and c-type dislocation densities were evaluated assuming that the screw dislocation only contributed to the lattice strain energy. This X-ray method was demonstrated to determine reliably the a- and c-type dislocation densities in the Zr–2.5Nb tube which agreed well with independently measured values for the same Zr–2.5Nb tube. For the first time, a procedure was developed to determine the distributions of a- and c-type dislocation densities from distributions of the line broadening of the basal planes and the prism planes. Through this procedure, the volume-averaged c- and a-type dislocation densities in the Zr–2.5Nb were determined to be 2.69 x 1014 and 9.7 x 1013/m2, respectively, which agree very well with those analyzed by transmission electron microscopy. The Nb content of the β-Zr phase was determined using an X-ray from a change in the lattice distance of the {100} planes, which agreed well with that by the electron diffraction spectroscopy analysis on the extracted β-Zr particles.

Determination of Dislocation Density and Composition of β-Zr in Zr–2.5Nb Pressure Tubes using X-ray and TEM. Y.S.Kim, S.S.Kim, Y.M.Cheong, K.S.Im: Journal of Nuclear Materials, 2003, 317[2-3], 117-29