Replicating PWR Primary Water Conditions in Low Pressure H2-Steam Environment to Study Alloy 600 Oxidation Processes

The effects of thermodynamic parameters associated with low pressure H 2 -steam on the oxidation behavior of Nickel have been investigated to simulate PWR primary water conditions.An Y 2 O 3 -ZrO 2 solid state reference electrode operated between 372 and 480 • C, and exposed to variable hydrogen partial pressures, was used to obtain in-situ potential measurements to identify the Ni/NiO transition.Microstructural analyses on Alloy 600 coupons exposed to H 2 -steam under different oxidizing conditions showed a marked dependence of the intergranular oxidation processes, as expected for a PWR environment.Overall, the H 2 -steam simulated an environment that can be considered to be representative of PWR primary water.