Corrosion behavior of Alloy 690 after cessation of zinc addition in simulated PWR primary water at 330 °C

The purpose of this work is to quantify the effect of zinc cessation on corrosion and release rates from Alloy 690 steam generator tubes that were previously oxidized in zinc-containing water. The corrosion tests were performed in 2 ppm Li and 10 0 0 ppm B water with and without 60 ppb zinc at 330 degrees C. The corrosion rates, release rates, and oxide thicknesses were determined based on descaling and gravimetric analysis methods and the results showed only a slight increase even after cessation of zinc addition. This is attributed to the zinc-containing chromium-rich inner oxide layer still remaining after the cessation of zinc addition. (c) 2021 Elsevier B.V. All rights reserved.

Automated summary

The study quantified the effect of zinc cessation on corrosion and release rates of Alloy 690 steam generator tubes previously oxidized in zinc-containing water. Results showed only a slight increase in corrosion rates even after cessation of zinc addition, attributed to the presence of zinc-containing chromium-rich inner oxide layer.