Microstructural aspects of accelerated deformation of Zircaloy nuclear reactor components during service

X-ray diffraction (XRD) and transmission electron microscopy (TEM) have been used to characterize microstructural and microchemical changes produced by irradiation in nuclear reactor core components fabricated from Zircaloy-2 and -4. These microstructural measurements have been correlated with the known deformation characteristics of the various components. The results show that the c-component defect structure in the as-fabricated state, in addition to that which develops during irradiation, is important in controlling the rate of irradiation-induced deformation. (orig.)