Effects of Hydrogen Peroxide on Intergranular Stress Corrosion Cracking of Stainless Steel in High Temperature Water, (I) Effects of Hydrogen Peroxide on Electrochemical Corrosion Potential of Stainless Steel.

Uchida, Shunsuke; Shigenaka, Naoto; Tachibana, Masahiko; Wada, Yoichi; Sakai, Masanori; Akamine, Kazuhiko; Ohsumi, Katsumi

doi:10.3327/jnst.35.301

Cited by 20 publications

(20 citation statements)

References 3 publications

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“…1,2) To determine the effects of H 2 O 2 , O 2 and their mixture on electrochemical corrosion potential (ECP) of type 304 stainless steel, the authors fabricated a high temperature, high-pressure water loop with a polytetrafluoroethylene (PTFE) inner liner which minimized H 2 O 2 decomposition and lowered possible oxygen concentration. [3][4][5][6][7] From in situ measurements, i.e., ECP and frequency dependent complex impedance (FDCI), made in previous papers, [7][8][9] the authors confirmed the following. (1) The ECP and FDCI data of the specimens exposed to 100 ppb H 2 O 2 were not affected by co-existing O 2 with the same level oxidant concentration and they were also not affected by pre-exposure to 200 ppb O 2 .…”

Section: Introductionsupporting

confidence: 68%

Effects of Hydrogen Peroxide on Corrosion of Stainless Steel, (IV) Determination of Oxide Film Properties with Multilateral Surface Analyses

Miyazawa¹,

Uchida²,

Satoh³

et al. 2005

J. Nucl. Sci. Technol.

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Corrosive conditions in BWRs are determined mainly by hydrogen peroxide (H 2 O 2 ). Then, a high temperature, high-pressure H 2 O 2 water loop was fabricated to identify the effects of H 2 O 2 on corrosion and stress corrosion cracking of stainless steel.By changing concentrations of H 2 O 2 and O 2 , in situ measurements of electrochemical corrosion potential (ECP) and frequency dependent complex impedance of test specimens were carried out and then characteristics of oxide film on the specimens were determined by multilateral surface analyses, i.e., laser Raman spectroscopy and secondary ion mass spectroscopy. The following points were experimentally confirmed.(1) The hematite ratio in the oxide films of the specimens exposed to H

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Section: Introductionsupporting

confidence: 68%

Effects of Hydrogen Peroxide on Corrosion of Stainless Steel, (IV) Determination of Oxide Film Properties with Multilateral Surface Analyses

Miyazawa¹,

Uchida²,

Satoh³

et al. 2005

J. Nucl. Sci. Technol.

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“…On the contrary, the peaks for magnetite (Fe3 0 4) type spinel were observed stronger for the specimen exposed to 0 2 than those to H2 0 2 . This result suggested that the dominant chemical form of oxide is magnetite type spinel or maghemite (1, that is the inverse spinel of the magnetite. The XRD cannot distinguish between magnetite and maghemite.…”

Section: Surface Oxide Analysismentioning

confidence: 97%

Effects Of Hydrogen Peroxide On Intergranular Stress Corrosion Cracking Of Stainless Steel in High Temperature Water, (IV)

Wada

Watanabe

Tachibana

et al. 2001

Journal of Nuclear Science and Technology

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In order to determine. the effects of hydrogen peroxide on electrochemical corrosion potential (ECP) of type 304 stainless steel (SUS304), ECPs were measured using a high temperature, high pressure water loop with polytetrafluoroethylene (PTFE) inner liner at controlled hydrogen peroxide concentration. It is observed that the ECP of SUS304 exposed to hydrogen peroxide is higher than that when exposed to oxygen at the same oxidant concentration. The ECP shows a hysteresis pattern for its concentration dependency. Those results were attributed mainly from the chemical form of oxide film on stainless steel specimens. The oxide film was affected by the corrosive circumstances. Hematite (a-Fe203) was observed for the specimens exposed to hydrogen peroxide, while Fe304 was a main oxide when exposed to oxygen. The difference of the anodic polarization curves between 02 and H202 environments was caused by the difference of the stability between a-Fe203 and Fe304. Since the a-Fe20 3 is reduced to the Fe 2 + when hydrogen is added to water, the ECP decreases with decreasing oxidant concentration without showing the hysteresis that keep the ECP higher value.

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“…[5][6][7][8] The material used was SUS304 with the chemical composition listed in Table 1. Prior to machining, the material was solution treated (1, 323 K×30 min WQ) and highly sensitized (1, 023 K×100 min+773 K × 24 h).…”

Section: Materials and Heat Treatmentmentioning

confidence: 99%

“…In particular, even though H 2 O 2 con-centrations which are attained in HWC are as low as 10 ppb, the ECP of SUS304 is still a higher value, such as around 0 mV vs. the standard hydrogen electrode (SHE). [4][5][6] This determines the IGSCC environment of structural materials even though the measured O 2 concentration has been reduced below 10 ppb in HWC. 7,8) In order to protect structural materials from IGSCC, new water chemistry control is needed: it can effectively reduce H 2 O 2 concentration or moderate the IGSCC regardless of the presence of a high concentration level oxidant, such as H 2 O 2 in reactor water.…”

Section: Introductionmentioning

confidence: 99%

Mitigation Effect of Alkaline Water Chemistry upon Intergranular Stress Corrosion Cracking of Sensitized 304 Stainless Steel.

Wada

Tachibana

Uetake

et al. 2001

J. Nucl. Sci. Technol.

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Alkaline water chemistry (AWC) has been studied as a new water chemistry control to mitigate intergranular stress corrosion cracking (IGSCC) of sensitized type 304 stainless steel (SUS304). The AWC was found to be capable of reducing crack growth rates (CGRs) of the IGSCC. At first, the direct effect of AWC upon IGSCC was studied experimentally. The 1/4T compact tension specimen was used for measurement of CGRs of the SUS304 in high temperature and high purity water. Crack length was monitored by a reversing direct current potential drop method. The CGR of SUS304 at 400 ppb O 2 concentration was reduced ten-fold when solution pH was increased to 9. During this time, electrochemical corrosion potential (ECP) of the specimen did not change so much. Second, it was predicted by a radiolysis calculation that the AWC would reduce H 2 O 2 concentration under the hydrogen water chemistry (HWC). Since the H 2 O 2 concentration was more effectively suppressed by AWC, the required hydrogen concentration in feedwater to lessen the ECP of the reactor components was lower in AWC than at neutrality. Therefore, an indirect effect, that is moderation of the corrosive environment, could also be expected in addition to the direct moderation effect under HWC condition.

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Effects of Hydrogen Peroxide on Intergranular Stress Corrosion Cracking of Stainless Steel in High Temperature Water, (I) Effects of Hydrogen Peroxide on Electrochemical Corrosion Potential of Stainless Steel.

Cited by 20 publications

References 3 publications

Effects of Hydrogen Peroxide on Corrosion of Stainless Steel, (IV) Determination of Oxide Film Properties with Multilateral Surface Analyses

Effects of Hydrogen Peroxide on Corrosion of Stainless Steel, (IV) Determination of Oxide Film Properties with Multilateral Surface Analyses

Effects Of Hydrogen Peroxide On Intergranular Stress Corrosion Cracking Of Stainless Steel in High Temperature Water, (IV)

Mitigation Effect of Alkaline Water Chemistry upon Intergranular Stress Corrosion Cracking of Sensitized 304 Stainless Steel.

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