Electrochemical Potential Measurements Under Simulated BWR Water Chemistry Conditions

Lin, Chien Chung; Smith, Frank; Ichikawa, Nagayoshi; Itow, Mikiro

doi:10.5006/1.3315913

Cited by 45 publications

(12 citation statements)

References 4 publications

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“…Specific examples of other types of metals, which under cathodic polarization will also involve reduction of oxygen to reactive intermediates, include aluminum, 46 copper, 47,48 and stainless steel. 49 Table 8 shows the extent of cathodic delamination of a reference coating without free radical scavengers and an identical coating modified with 3 wt% of free radical scavenger (DBTHQ) for various types of metallic substrates under cathodic polarization.…”

Section: Other Types Of Substratesmentioning

confidence: 99%

Reduction of cathodic delamination rates of anticorrosive coatings using free radical scavengers

Sörensen

Weinell²,

Dam‐Johansen

et al. 2010

J Coat Technol Res

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Cathodic delamination is one of the major modes of failure for anticorrosive coatings subjected to a physical damage and immersed in seawater. The cause of cathodic delamination has been reported to be the result of a chemical attack at the coating-steel interface by free radicals and peroxides formed as intermediates in the cathodic reaction during the corrosion process. In this study, antioxidants (i.e., free radical scavengers and peroxide decomposers) have been incorporated into various generic types of coatings to investigate the effect of antioxidants on the rate of cathodic delamination of epoxy coatings on cold rolled steel. The addition of <5 wt% free radical scavengers to epoxy coatings improved the resistance toward cathodic delamination by up to 50% during seawater immersion, while peroxide decomposers had a limited effect. Testing using substrates prepared from stainless steel, copper, aluminum, galvanized steel, and brass also showed a reduction in the rate of cathodic delamination when the coating was modified with a free radical scavenger. The protective mechanism of free radical scavengers investigated for the primers are similar to that of antioxidants used for protection against photochemical degradation by UV-radiation of top coatings. Both substrate corrosion and degradation of a coating exposed to UV-radiation lead to the formation of free radicals as reactive intermediates.

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Section: Other Types Of Substratesmentioning

confidence: 99%

Reduction of cathodic delamination rates of anticorrosive coatings using free radical scavengers

Sörensen

Weinell²,

Dam‐Johansen

et al. 2010

J Coat Technol Res

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show abstract

“…(3) According to water chemistry simulation, the effect of hydrogen water chemistry on decreasing oxygen and hydrogen peroxide is different between 784 MWe BWR and 1,100 MWe BWR. (4) The corrosion potentials at several points in the reactor pressure vessel bottom region were evaluated. At the jet pump outlet and the shroud support leg, a rather high hydrogen concentration is necessary in the feed water to reduce the potential.…”

Section: Discussionmentioning

confidence: 99%

“…The effect of flow velocity on corrosion potential becomes remarkable under the condition that there is a low oxidant concentration in the reactor water. 4) In the bottom region of the reactor pressure vessel (RPV), the water flow pattern and flow velocity are very complex because there are many in-core monitor (ICM) housings and control rod drive (CRD) guide tubes. 5) Evaluation of the corrosion potential in this bottom region is, therefore, very difficult.…”

Section: Introductionmentioning

confidence: 99%

Precise Evaluation of Corrosion Environments of Structural Materials under Complex Water Flow Condition, (I)

Ichikawa¹,

Hemmi²,

Takagi³

2003

Journal of Nuclear Science and Technology

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To estimate the corrosion potentials of structural materials under complex water flow condition, such as reactor pressure vessel (RPV) bottom region of Boiling Water Reactors (BWRs), a method was newly developed. Threedimensional water flow analysis was performed and corrosion potentials of structural materials were calculated on the basis of the flow analysis results. Water flow analysis showed the velocities in the RPV bottom region varied from about 0.1 ms −1 to 4.5 ms −1 . From the corrosion potential estimation under hydrogen water chemistry (HWC) condition, at the jet pump outlet and shroud support leg, a rather large amount of hydrogen had to be added to reduce the potential because of high flow velocity condition. Conversely, a small amount of hydrogen was sufficient in the case of the stub tube of the control rod drive (CRD) guide tubing located in the center of the bottom region.

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“…During the experiment, pure hydrogen can also be added to obtain a higher partial pressure of hydrogen when needed. Regarding the initial concentration of the dissolved hydrogen, it has been chosen to ensure that the platinum wire can be considered as a pseudo-reference electrode [26,28].…”

Section: Environmentmentioning

confidence: 99%

Electrochemical behaviour of 316L stainless steel exposed to representative chemistry in pressurised water reactors under proton radiation

Wang

Perrin

Corbel

et al. 2015

Journal of Electroanalytical Chemistry

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Electrochemical Potential Measurements Under Simulated BWR Water Chemistry Conditions

Cited by 45 publications

References 4 publications

Reduction of cathodic delamination rates of anticorrosive coatings using free radical scavengers

Reduction of cathodic delamination rates of anticorrosive coatings using free radical scavengers

Precise Evaluation of Corrosion Environments of Structural Materials under Complex Water Flow Condition, (I)

Electrochemical behaviour of 316L stainless steel exposed to representative chemistry in pressurised water reactors under proton radiation

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