This work was aimed at predicting, at the atomic scale, the binding energies of vacancies to vacancy clusters in Zr. Empirical laws established on the basis of simulation results were suggested, describing the size-dependence of the formation and binding energies of small voids (involving up to 1000 atoms) as well as basal, prismatic and pyramidal vacancy loops involving the same number of vacancies. The detailed atomic configurations of the loops were examined and characterized by means of areas where atoms were mis-coordinated, and by strain fields. The importance of mis-coordinated areas was emphasized by an examination of self-interstitial atom diffusion mechanisms in the vicinity of basal vacancy loops. The loops acted as sinks for self-interstitial atoms that, depending upon the temperature, migrated 1- or 3-dimensionally to the mis-coordinated areas from which they could not escape. By this mechanism, the annihilation of vacancy loops by self-interstitial atom absorption was inhibited.

Vacancy Dislocation Loops in Zirconium and their Interaction with Self-Interstitial Atoms. D.Kulikov, M.Hou: Journal of Nuclear Materials, 2005, 342[1-3], 131-40