The effect of hydrogen peroxide on the stress corrosion cracking of 304 stainless steel in high temperature water

Ishida

Journal of Nuclear Science and Technology

et al. 2009

In order to improve the accuracy of electrochemical corrosion potential (ECP) calculations, information about the effects of the flow velocity, the type of oxidization species, the oxide film thickness, and the oxide film classification on the polarization curve is needed. Polarization curve measurements were studied here with that information goal in mind. A wire-shaped working electrode was employed to remove the IR drop caused by high solution resistance, which makes it difficult to apply a proper potential to the working electrode. In order to measure the static state current, the potential scanning condition was optimized. It was confirmed that a steady-state current can be measured by establishing a potential scanning rate for applying a potential not greater than 0.01 mVÁs À1 with a step-shaped waveform. This method was employed to measure the anodic polarization curve of type 304 stainless steel in deaerated 553 K high-purity water. The passivation behavior was clearly observed. Also, the cathodic polarization curves in water containing dissolved oxygen of less than 1000 ppb were measured. The oxygen concentration dependence of ECP was calculated from measured polarization curves. The ECPs calculated using the measured polarization curves were in good agreement with those measured with an electrometer, confirming the validity of the measured polarization curves.

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Section: Presumption Of Ecp From Polarization Curvessupporting

confidence: 62%

Section: Discussionmentioning

confidence: 99%

Section: Presumption Of Ecp From Polarization Curvesmentioning

confidence: 99%

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Study of Polarization Curve Measurement Method for Type 304 Stainless Steel in BWR High Temperature-High Purity Water

Ishida

Journal of Nuclear Science and Technology

et al. 2009

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“…In this paper, ECPs were recalculated by Equation (15) using the fitted cathodic polarization curves (Figure 10(a)). Both the calculated ECPs and directly measured ECPs which include some literature data [9,10,[16][17][18][19] are shown in Figure 11. All plotted data were directly measured using an electrometer.…”

Section: Ssmentioning

confidence: 99%

“…The measured ECPs had some scatter, but were within about 0.2 V. Both the calculated ECPs and the envelope curve of the directly measured ECPs [9,10,[16][17][18][19] had the S-shaped curve with dependence on the logarithm of O 2 concentration. The calculated ECPs were located inside of the envelope curve of the directly measured ECPs [9,10,[16][17][18][19]. Consequently, it was clearly confirmed that the calculation method using fitted cathodic polarization curves was able to reproduce the measured ECP behavior.…”

Section: Ssmentioning

confidence: 99%

Cathodic polarization curves of the oxygen reduction reaction on various structural materials of boiling water reactors in high temperature–high purity water

Ishida

Journal of Nuclear Science and Technology

et al. 2012

Cathodic polarization curves of the O 2 reduction reaction were measured by using electrodes made from typical structural materials of boiling water reactors (BWRs) to evaluate the effects of kind of material on the electrochemical corrosion potential (ECP) calculation. To estimate ECPs at any region in the BWRs on the basis of the BWR environmental conditions, anodic and cathodic polarization curves should be obtained in advance under relevant conditions. The concentration of oxidants such as O 2 and H 2 O 2 in coolant changes depending on the region in which they exist. As well, reduction reaction rates might differ depending on the kind of materials. In this work, the cathodic polarization curves of type 316L stainless steel (316L SS) and Alloy 182 were measured in high purity water at 553 K with different O 2 concentrations and compared with those of type 304 SS (304 SS). The results showed that the cathodic polarization curves differed depending on the kind of materials at the activation-controlled region. But, the difference in the ECP vs. O 2 concentration relationship was small when the ECPs were calculated by using both anodic and cathodic polarization curves measured on the objective material.

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The Electrochemical Corrosion Potential and Stress Corrosion Cracking of 304 Stainless Steel under Low Hydrogen Peroxide Concentrations

Watanabe

Ninth International Symposium on Environmental Degradation of Materials in Nuclear Power Systems—Water Reactors

et al. 1999