Electrochemical Study of Pre- and Post-Transition Corrosion of Zr Alloys in PWR Coolant

Corrosion properties of Zr-Sn and Zr-Nb zirconium alloys were studied under simulated PWR conditions at temperatures up to 340 oC and 15MPa using in-situe electrochemical impedance spectroscopy and polarization measurements. EIS spectra were obtained in a wide range of frequencies. It enabled to gain information of both dielectric properties of oxide layers developing on the Zr-alloys surface and of the kinetics of the corrosion process and the associated charge and mass transfer phenomena. Experiments were run for more than 380 days, thus the study of all the corrosion stages was possible. Experimental impedance spectra were approximated by equivalent circuits based models. Jonscher-type analysis was applied to estimate frequency independent oxide capacitance. A model based on integrated Stern-Geary equation was developed to correlate instant and integral corrosion rates of zirconium alloys.

MACAK Jan;  NOVOTNY Radek;  SAJDL Petr;  RENCIUKOVA Veronika;  VRTILKOVA Vera; 

2012-07-19

The Minerals, Metals & Materials Society (TMS)

JRC65073