Investigation via Electron Microscopy and Electrochemical Impedance Spectroscopy of the Effect of Aqueous Zinc Ions on Passivity and the Surface Films of Alloy 600 in PWR PW at 320 °C-Reference-Cited by-同舟云学术

Investigation via Electron Microscopy and Electrochemical Impedance Spectroscopy of the Effect of Aqueous Zinc Ions on Passivity and the Surface Films of Alloy 600 in PWR PW at 320 °C

Published:2023-01-19 Issue:1 Volume:4 Page:54-89
ISSN:2624-5558
Container-title:Corrosion and Materials Degradation
language:en
Short-container-title:CMD

Author:

Jiang Yifan,Bustillo Karen C.^ORCID,Devine Thomas M.

Abstract

Aqueous zinc ions lower the corrosion rate of Alloy 600, which helps lower the radiation dose rate in pressurized water reactors (PWRs). The influence of zinc on the electrochemical behavior of Alloy 600 in PWR primary water (PW) at 320 °C was investigated using a combination of electron microscopy and electrochemical impedance spectroscopy (EIS). Secondary electron microscopy (SEM) and scanning transmission electron microscopy (STEM)/energy-dispersive X-ray spectroscopy (EDS) indicated duplex surface films were formed on the Alloy 600 in PWR PW with and without 100 ppb of zinc. There was no effect of zinc on the chromium-rich inner layer (IL) (of Cr2O3 and/or CrOOH). Zinc had a significant effect on the outer layer (OL). In the absence of zinc, a highly porous OL formed that was mostly composed of nickel oxide whiskers. In the presence of zinc, a zinc-containing, denser OL of oxide was formed. The EIS data were acquired in laboratory simulated PWR PW at 320 °C with and without 100 ppb zinc. The spectra were measured at nine different values of potential that spanned a 500 mV-wide range. The EIS indicated there was no effect of zinc on the oxidation rate of metals at the alloy/IL interface nor on the transport of ions through the IL. Zinc lowered the corrosion rate because the dense OL inhibited the release of nickel ions from the IL into the solution.

Funder

Electric Power Research Institute of Palo Alto, CA

Publisher

MDPI AG

Subject

General Medicine

Link

https://www.mdpi.com/2624-5558/4/1/5/pdf

Reference47 articles.

1. (2021, January 01). Westinghouse Nuclear Services/Engineering Services NS-ES-0089, January 2017. Available online: https://www.westinghousenuclear.com/Portals/O/operating%20plant%20services/engineering/nsss%20system%208%20component%20analysis/NS-ES-0089%20Zinc%20Addition%20Flysheet.

2. Pathania, R., Yagnik, S., Gold, R., Dove, M., and Kolstad, E. (1995, January 6–10). Evaluation of Zinc Addition to Primary Coolant of Farley-2 Reactor. Proceedings of the 7th International Symposium on Environmental Degradation of Materials in Nuclaer Power Systems–Water Reactors, Breckenridge, CO, USA.

3. Pathania, R., Cheng, B., Dove, M., Gold, R., and Bergmann, C. (1997, January 10–14). Evaluation of Zinc Addition to Primary Coolant of Farley-2 Reactor. Proceedings of the 8th International Symposium on Environmental Degradation of Materials in Nuclaer Power Systems–Water Reactors, Amelia Island, FL, USA.

4. Haas, V.C., and Perkins, D. (2011). Research Report No. VTT-R-05511-11, Technical Research Center of Finland. Zinc Injection Update.

5. Ocken, H., Fruzzetti, K., Frattini, P., and Wood, C.J. (2002, January 22–26). Recent Developments in PWR Zinc Injection. Proceedings of the International Conference on Water Chemistry in Nuclear Reactor Systems, Avignon, France.