The direct observation of irradiation damage in zirconium and its alloys

Direct observations of the dislocation climb rate in electron-irradiated zirconium and dilute zirconium alloys are reported. These observations allow a detailed physical model to be constructed which provides a consistent view of irradiation growth in these materials, under electron irradiation. We are inevitably led to postulate that the vacancy is more mobile (0.65 eV) than previously thought (1.2 eV) and that the tin present in Zircaloy acts as an atom-sized vacancy trap with a binding energy of 0.3 eV. The dependence of the results obtained on the foil geometry and the probable surface contamination during irradiation are discussed with reference to extensions to neutron-irradiated bulk materials. (orig.)