Quantitative Assessment of Submodes of Stress Corrosion Cracking on the Secondary Side of Steam Generator Tubing in Pressurized Water Reactors: Part 2

Staehle, R. W.; Gorman, J.A.

doi:10.5006/1.3299232

Cited by 87 publications

(33 citation statements)

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“…(ii) Between 10 3 and10 5 Hz, a constant value could be observed, which represented the electrolyte resistance. In alkaline solutions, -OH increases the corrosion resistance or stability of the passive film.…”

Section: Effect Of Ph On Corrosion Type and Corrosion Potential-mentioning

confidence: 99%

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pH Effect on Sulfur-Induced Passivity Degradation of Alloy 800 in Simulated Crevice Chemistries

Xia

Zhu

Behnamian

et al. 2014

J. Electrochem. Soc.

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The effects of pH on sulfur-induced passivity degradation of Alloy 800 in simulated crevice chemistries were evaluated using electrochemical impedance spectroscopy (EIS), secondary ion mass spectroscopy (SIMS), and Mott-Schottky analysis methods. Experimental results reveal that the detrimental effect of impurities containing sulfur at the reduced or intermediate oxidation level (S x ) on the passivity of Alloy 800 depends significantly on the solution pH. In neutral crevice (NC) chemistry containing chloride ions, the S x obstructs the healing process during repassivation, retards the dehydration reaction and also incorporates H, -OH and S into the passive film. However, the detrimental effect of S x is insignificant in an alkaline crevice (AKC) solution due to a change in surface adsorption and surface charge. Impurities containing sulfur at the reduced or intermediate oxidation level would cause Alloy 800 to lose its passivity and become active in an acidic crevice (AC) chemistry. Experimental evidence also indicates that the solution pH alters the semiconductor type of the surface film -from n-type in NC solution to p-type in AKC solution.

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Section: Effect Of Ph On Corrosion Type and Corrosion Potential-mentioning

confidence: 99%

“…[3][4][5] The local concentrations of impurities, such as sodium, potassium, calcium, chloride, sulfate, etc., can be increased up to six orders of magnitude, resulting in a localized highly aggressive environment within the crevices. Sulfate concentrations of up to 10 ppb (by weight) exist in the SG blowdown.…”

mentioning

confidence: 99%

pH Effect on Sulfur-Induced Passivity Degradation of Alloy 800 in Simulated Crevice Chemistries

Xia

Zhu

Behnamian

et al. 2014

J. Electrochem. Soc.

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“…11,12 In order to avoid elevated corrosion potential of SG alloy and minimize oxygen content, hydrazine is intentionally added to the secondary loop of SGs, leading to a reduction of sulfate to HS − , H 2 15 which have been recognized to enhance active dissolution of metal, increase stress corrosion cracking and pitting susceptibility. [15][16][17] As pointed out by Newman, 2 some corrosion phenomena in SG tubing with the presence of 'reduced' sulfur species and oxygen have been recognized to occur at low temperature. Therefore, it is necessary to investigate corrosion degradation of SG tubing at low temperature.…”

mentioning

confidence: 99%

Factors Influencing Passivity Breakdown on UNS N08800 in Neutral Chloride and Thiosulfate Solutions

Wang

Shi

et al. 2017

J. Electrochem. Soc.

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In this work, the passivity degradation of UNS N08800 in solutions containing Cl − and S 2 O 3 2− is studied by using polarization curve, electrochemical impedance spectroscopy (EIS), and X-ray photoelectron spectroscopy (XPS). Experimental results reveal that the passivity breakdown heavily depends on anodic potentials, concentration ratios of Cl − to S 2 O 3 2− , and the composition of materials. A combined effect between Cl − and S 2 O 3 2− on pitting corrosion is observed at high anodic potentials at which the passive film is broken down; in this situation, S 2 O 3 2− ions can enter into the pits by electromigration, and they are reduced to S ads and S 2− , stabilizing the metastable pits and accelerate the pit growth rate. However, there is no such combined effect at low anodic potentials when the passive film is intact, on the contrary, S 2 O 3 2− is beneficial to passivity in chloride solutions. At low anodic potentials, the interaction of S 2 O 3 2− with an intact passive layer is weak, and the adsorption of S 2 O 3 2− would mitigate the detrimental effect of Cl − ions.

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“…An example of the use of Pourbaix diagram to delineate various regions of SCC of a Ni-base alloy, alloy 600, in the secondary side of a steam generator is shown in Fig. 21.8 (Staehle and Gorman, 2004). Secondary side stress corrosion cracking in steam generators predominantly occurs in crevices between tubes and tube-supports, tube sheets, or sludge formed on tube sheet.…”

Section: Thermodynamic Modelsmentioning

confidence: 98%

Models for predicting corrosion

Sridhar

2008

Techniques for Corrosion Monitoring

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Quantitative Assessment of Submodes of Stress Corrosion Cracking on the Secondary Side of Steam Generator Tubing in Pressurized Water Reactors: Part 2

Cited by 87 publications

References 0 publications

pH Effect on Sulfur-Induced Passivity Degradation of Alloy 800 in Simulated Crevice Chemistries

pH Effect on Sulfur-Induced Passivity Degradation of Alloy 800 in Simulated Crevice Chemistries

Factors Influencing Passivity Breakdown on UNS N08800 in Neutral Chloride and Thiosulfate Solutions

Models for predicting corrosion

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