Corrosion and Corrosion Product Release in Neutral Feedwater

Brush, E.G.; Pearl, W.L.

doi:10.5006/0010-9312-28.4.129

Cited by 27 publications

(11 citation statements)

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“…(2) Oxygen concentration in feed water can be kept at a required level to suppress the flow-assisted corrosion (FAC) of carbon steel in the feed water line (about 0.47 mM). 35,36) An example of hydrazine and hydrogen co-injection to the BWR is shown schematically in Fig. 11.…”

Section: Applicability Of Hydrazine and Hydrogen Co-injection To Bwrsmentioning

confidence: 99%

Hydrazine and Hydrogen Co-injection to Mitigate Stress Corrosion Cracking of Structural Materials in Boiling Water Reactors, (I) Temperature Dependence of Hydrazine Reactions

Ishida

Wada

Tachibana

et al. 2006

Journal of Nuclear Science and Technology

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Hydrazine and hydrogen co-injection into reactor water is considered a new mitigation method of stress corrosion cracking in BWRs. Fundamental data such as the thermal decomposition of hydrazine, the reaction of hydrazine with oxygen and with hydrogen peroxide at temperatures ranging from 150 to 280 C are needed to evaluate suitability of this method. Reactions in bulk water were studied in a polytetrafluoroethylene pipe to separate surface reaction effects. The results were as follows. (1) The orders of the apparent reaction rate of hydrazine with oxygen were 1 and 0.5 for hydrazine and oxygen concentrations, respectively (À . Based on these data, the applicability of hydrazine and hydrogen co-injection into BWRs was considered. Hydrazine introduction to reactor water was confirmed to be accompanied by only 1% decomposition. The concentration of oxygen, which is injected to suppress the flow-assisted corrosion of carbon steel in current BWR operation, would decrease due to the reaction of hydrazine with oxygen. However oxygen concentration in feed water could be maintained at the required level if the concentration of oxygen injected in condensate water was at most doubled compared to the current operating concentration.

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Section: Applicability Of Hydrazine and Hydrogen Co-injection To Bwrsmentioning

confidence: 99%

Hydrazine and Hydrogen Co-injection to Mitigate Stress Corrosion Cracking of Structural Materials in Boiling Water Reactors, (I) Temperature Dependence of Hydrazine Reactions

Ishida

Wada

Tachibana

et al. 2006

Journal of Nuclear Science and Technology

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“…1 Earlier studies had revealed that the fi lm formed on iron in 288°C deoxygenated water consisted of an inner, conformal layer of magnetite (Fe 3 O 4 ) that grows into the iron and an outer layer of loosely packed grains of Fe 3 O 4 that precipitate from the aqueous phase. [2][3][4][5][6][7][8][9] Our relatively recent investigation of iron used a combination of in situ Raman spectroscopy (RS), in situ surface-enhanced Raman spectroscopy (SERS), and ex situ scanning electron microscopy (SEM), and we confi rmed these results in the following manner. 1 Submicron-sized gold particles were deposited on the original iron surface, which acted to enhance the Raman spectra of species present on the iron surface, such as its passive fi lm.…”

Section: Introductionmentioning

confidence: 56%

“…The horizontal line drawn at -0.466 V in Figure 10 is the calculated value of the equilibrium potential at pH 5 One of the motivations for this research was to determine if the susceptibility of sensitized Type 304 stainless steel is related to the type of surface fi lms that form over sensitized grain boundaries. The results of this study are quite consistent with the hypothesis that the identity of fi lms affects the susceptibility of the alloy to IGSCC.…”

Section: Discussionmentioning

confidence: 99%

Influence of Oxygen Concentration of 288°C Water and Alloy Composition on the Films Formed on Fe-Ni-Cr Alloys

Kumai

Devine

2007

CORROSION

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In situ identifi cation of the fi lms formed on alloys of Fe-13Cr-10Ni, Fe-5Cr-10Ni, and Type 304 (UNS S30400) stainless steel immersed in high-temperature (288°C), high-purity water was performed using Raman spectroscopy, surface-enhanced Raman spectroscopy, and scanning electron microscopy. The fi lms were a function of the alloy's chromium concentration and corrosion potential, which was controlled by the water's dissolved oxygen concentration. Below a critical value of the corrosion potential, the surface fi lms were composed of M 3 O 4 . The critical value of potential was approximately equal to the equilibrium potential of Fe 3 O 4 ⇔ Fe 2 O 3 (magnetite ⇔ hematite), -0.466 V. At potentials above -0.466 V, the fi lms consisted of M 3 O 4 and an outer layer of M 2 O 3 . The particular modifi cation of M 2 O 3 depended on the alloy's composition and corrosion potential. For alloys containing 5% Cr and 13% Cr, the outer layer was α-M 2 O 3 at potentials just above -0.466 V and a mixture of α-M 2 O 3 and γ-M 2 O 3 at potentials well above -0.466 V. For Type 304 stainless steel, the outer layer was γ-M 2 O 3 at lower potentials and a mixture of α-M 2 O 3 and γ-M 2 O 3 at higher potentials.

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“…Among the several corrosion products, Co released from the stainless steel heater tubes in the feedwater line is assumed to the main contributor to dose rate"). Measured data of release rates are reported (2), however they are not sufficient to explain release phenomena in general, because such conditions as temperature, oxygen concentration and flow velocity are diversified.…”

Section: Introductionmentioning

confidence: 98%

Temperature Dependence of Cobalt Release Rate from Stainless Steel in Neutral Water

Ozawa

Uchida

Kitamura

1983

Journal of Nuclear Science and Technology

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In order to evaluate the release source of Co from heated tubes of the feedwater line of BWR, Co release rate measurements were carried out by measuring 6oCo released from irradiated stainless steel in contact with neutral water at an oxygen concentration of 20ppb. The temperature-and time-dependences on Co release rate were studied for 670 h release experiments; the rate was found to decrease in proportion to t-'12 ( t : exposure time) and to have its maximum value around 240°C. An empirical equation was obtained for the Co release rates in the temperature range of 150-240°C. Rco= 1.9 x lo6 exp (-14,300/ ( R T ) ) t-'12 where Rco : Co release rate (mg/ (dm2-month)), R : Gas constant (cal/ (mol.deg.)), 7 ' : Exposure temperature (K) and t : Exposure time (h). Decrease in the Co release rate with temperatures over 250'C, seemed to be ascribed to the formation of a protective oxide layer on the surface of stainless steel.

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Corrosion and Corrosion Product Release in Neutral Feedwater

Cited by 27 publications

References 0 publications

Hydrazine and Hydrogen Co-injection to Mitigate Stress Corrosion Cracking of Structural Materials in Boiling Water Reactors, (I) Temperature Dependence of Hydrazine Reactions

Hydrazine and Hydrogen Co-injection to Mitigate Stress Corrosion Cracking of Structural Materials in Boiling Water Reactors, (I) Temperature Dependence of Hydrazine Reactions

Influence of Oxygen Concentration of 288°C Water and Alloy Composition on the Films Formed on Fe-Ni-Cr Alloys

Temperature Dependence of Cobalt Release Rate from Stainless Steel in Neutral Water

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