About the effect of high hydrazine chemistry on FAC occurrence in PWR's Steam Generators

Bouvier, O. de; Bouchacourt, M.; Vermorel, F.; Millet, L.

doi:10.1680/wconrs8v2.29583.0024

Cited by 2 publications

(6 citation statements)

References 3 publications

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“…7,11) On the other hand, FAC is suppressed by 0.05 mmolÁkg À1 oxygen injection for both 180, 210 and 235 C solutions. 7,11) The effects of pH and history of hydrazine concentration on FAC acceleration were also studied in detail. 10) As well, increase of electrochemical corrosion potential (ECP) by oxygen injection is considered to suppress FAC.…”

Section: Introductionmentioning

confidence: 94%

“…FAC acceleration was not observed, as was also the case in 235 C solution. [7][8][9][10] Oxygen injection also suppressed the corrosion release rate for hydrazine injection to one fifth or less. The oxide film growth rate for hydrazine injection was larger than that for no hydrazine injection.…”

Section: Corrosion Testsmentioning

confidence: 99%

“…FAC acceleration was not observed in this study, although it has been reported in the literature. [7][8][9][10] Oxide film was also not porous according to the SEM photographs of film cross sections. The differences were attributed to the differences of test conditions such as temperature, hydrazine concentration, pH, and oxygen concentration.…”

Section: Acceleration Of Fac By Hydrazine Injectionmentioning

confidence: 99%

“…The differences were attributed to the differences of test conditions such as temperature, hydrazine concentration, pH, and oxygen concentration. FAC acceleration was not observed at 180 and 210 C but was seen at 235 C. [7][8][9][10][11] The temperature of this work (215 C) was lower than that at which FAC acceleration was observed. FAC rate decreased for hydrazine concentration above 4.7 mmolÁkg À1 even at 235 C. The concentrations of hydrazine of this work (25, 47 mmolÁkg À1 ) were five to ten times larger.…”

Section: Acceleration Of Fac By Hydrazine Injectionmentioning

confidence: 99%

“…7) The effect of hydrazine and dissolved oxygen on FAC has been studied in the pH adjusted condition at 180, 210 or 235 C. [7][8][9][10][11] For no oxygen injection, FAC is not accelerated at 180 and 210 C, but it is at 235 C. [7][8][9][10][11] Acceleration of FAC at 235 C is attributed to oxide film on the surfaces being made porous by hydrazine. 7,11) On the other hand, FAC is suppressed by 0.05 mmolÁkg À1 oxygen injection for both 180, 210 and 235 C solutions. 7,11) The effects of pH and history of hydrazine concentration on FAC acceleration were also studied in detail.…”

Section: Introductionmentioning

confidence: 99%

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Hydrazine and Hydrogen Co-injection to Mitigate Stress Corrosion Cracking of Structural Materials in Boiling Water Reactors (V) Effects of Hydrazine and Dissolved Oxygen on Flow Accelerated Corrosion of Carbon Steel

Ishida

Wada

Tachibana

et al. 2007

Journal of Nuclear Science and Technology

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Hydrazine and hydrogen co-injection into reactor water via the feed water line can mitigate stress corrosion cracking in BWRs. The effects of water quality variation due to hydrazine injection on flow accelerated corrosion (FAC) of carbon steel used in the BWR feed water line should be considered from the viewpoints of radioactive exposure, radioactive waste generation and plant integrity. Optimization of oxygen injection into feed water was considered to suppress FAC during hydrazine and hydrogen co-injection. In this report, corrosion tests of carbon steel were made in hydrazine and/or dissolved oxygen injected solutions (conditions: no pH adjustment by ammonia; temperature = 215 C; flow rate = 3.5 mÁs À1) to study the effects of dissolved oxygen and hydrazine on FAC. Hydrazine and oxygen co-injection suppressed the total corrosion rate by about 1/5 compared with the case of 0 mmolÁkg À1 hydrazine and <0:06 mmolÁkg À1 oxygen injection. With hydrazine and oxygen co-injection, the inner layer, which is protective oxide, was close packed. Thickness of the inner layer also became larger compared with the case for only hydrazine injection or only oxygen injection.-Fe 2 O 3 , which is thermodynamically more stable than Fe 3 O 4 , was formed in addition to Fe 3 O 4 which was the single species formed for the case of only hydrazine injection. From these results, it was concluded FAC will be suppressed by keeping the oxygen concentration at the current level in BWRs (about 1 mmolÁkg À1) if hydrazine and hydrogen co-injection is applied.

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