Irradiation growth in annealed Zircaloy-2

Irradiation growth in annealed Zircaloy-2 has been studied at 353 K and 553 K. Growth is initially rapid during irradiation at 353 K but saturates above a dose of 2 X 1024 n/m2. The saturation growth strain is found to be strongly dependent upon crystallographic texture. At 553 K, growth in longitudinal specimens attenuates with dose but does not saturate up to a dose of 12.3 X 1024 n/m2; in transverse specimens growth is observed to saturate at a dose of less than 1.3 X 1024 n/m2. The effect of changing irradiation temperature has been studied. The observed growth behaviour is interpreted in terms of a growth model in which growth is produced by the formation of sub-microscopic interstitial clusters on prism planes, possibly combined with a small volume increase. (Auth.)