Abstract
Corrosion experiments in autoclaves and in the Ågesta reactor have been made on Zircaloy-2 with different surface treatments, i.e. pickling, pickling and electropolishing or electropolishing only. The autoclave experiments were carried out at 250° (water, 4 years), 300° (water, 3 years), 350° (water and steam, 240 days) and 400°(steam, 432 days). The weight-gain and hydrogen absorption agree with previously reported figures, the major effect of surface treatment being a higher initial corrosion rate for pickled specimens than for pickled and electropolished specimens. Measurements of impedance and true surface area on material with different surface treatment did not show any correlation with the difference in corrosion rate. Determination of the amount of fluorine on the surface and in the oxide yielded higher values for the pickled material which agrees with previous experience of an accelerating effect of fluorine. The fluorine gradient in the oxide followed a simple diffusion function.
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