Influence of Dissolved Hydrogen on Oxide Film and PWSCC of Alloy 600 in PWR Primary Water.

Nakagawa, Tomokazu; Totsuka, Nobuo; Terachi, Takumi; Nakajima, Nobuo

doi:10.3327/jnst.40.39

Cited by 16 publications

(15 citation statements)

References 4 publications

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“…10) From these results it is seen that the oxide films formed below 1.0 ppm of DH are relatively thick and rich in nickel, whereas those formed at 2.0 ppm of DH or higher are rather thin and rich in chromium and iron. It is clear that DH affects oxide film structure.…”

Section: Introductionmentioning

confidence: 83%

Influence of Dissolved Hydrogen on Structure of Oxide Film on Alloy 600 Formed in Primary Water of Pressurized Water Reactors

Terachi¹,

Totsuka²,

Yamada³

et al. 2003

J. Nucl. Sci. Technol.

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In order to investigate the relationship between the susceptibility of primary water stress corrosion cracking (PWSCC) in Alloy 600 and the content of dissolved hydrogen (DH) in the primary water of pressurized water reactors (PWR), structural analysis of oxide films formed under four different DH conditions in simulated primary water of PWR was carried out using a grazing incidence X-ray diffractometer (GIXRD), a scanning electron microscope (SEM) and a transmission electron microscope (TEM). In particular, to perform accurate analysis of the thin oxide films, the synchrotron radiation of SPring-8 was used for GIXRD.It has been observed that the oxide film is mainly composed of nickel oxide, under the condition without hydrogen. On the other hand, needle-like oxides are formed at 1.0 ppm of DH. In the environment of 2.75 ppm of DH, the oxide film has thin spinel structures. From these results and phase diagram consideration, the condition around 1.0 ppm of DH corresponds to the boundary between stable NiO and spinel oxides, and also to the peak range of PWSCC susceptibility. This suggests that the boundary between NiO and spinel oxides may affect the SCC susceptibility.

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Section: Introductionmentioning

confidence: 83%

Influence of Dissolved Hydrogen on Structure of Oxide Film on Alloy 600 Formed in Primary Water of Pressurized Water Reactors

Terachi¹,

Totsuka²,

Yamada³

et al. 2003

J. Nucl. Sci. Technol.

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show abstract

“…7a), the thicknesses of oxide films can be estimated. The point where the intensity of oxygen level reaches 50% of its initial value is taken as the interface between the oxide film and metal substrate [4,10]. The oxygen level after 30 s sputtering was taken as the initial oxygen content and the sputtering time when the oxygen content was half of this value corresponded to the interface.…”

Section: Methodsmentioning

confidence: 99%

“…Up to now, in order to elucidate the oxidation process, some studies have been done to analyze the formed oxide films [2][3][4][5][6][7][8][9]. And the effects of different water chemistry parameters such as dissolved hydrogen (DH) [10][11][12][13][14], pH [15,16], temperature [15,17,18], Li concentration [19] and Zn injection [20,21] on the oxidation behaviors of Ni-base alloys have also been investigated. Dissolved oxygen concentration (DO) is also an important parameter that is worthy of scientific research efforts because it can significantly affect the oxidation behavior and hence the service performance of materials.…”

Section: Introductionmentioning

confidence: 99%

Influence of dissolved oxygen concentration on the oxide film formed on Alloy 690 in high temperature water

Kuang

Han

2013

Corrosion Science

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“…Dissolved hydrogen concentration is considered to be one of the factors that induce PWSCC, and the crack propagation rate of PWSCC is maximal at 10 cm 3 (STP a ) of hydrogen per kg of water. 7) Thus, the optimization of DH concentration is proposed and studied. 8) If hydrogen may initiate PWSCC or accelerate crack propagation, it is useful to develop alternative techniques of hydrogen addition.…”

Section: Introductionmentioning

confidence: 99%

Numerical Simulation on Effect of Methanol Addition on Coolant Radiolysis in Pressurized Water Reactor

Sunaryo

Domae

2008

J. Nucl. Sci. Technol.

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The addition of alcohol into the primary coolant of pressurized water reactors (PWRs) was proposed as an alternative of hydrogen addition. The radiolysis of the coolant in the presence of methanol was simulated, assuming a batch system and changing dose rate. At 300 C, the addition of 4.0 ppm methanol shows an equivalent scavenging capacity toward the OH radical to a typical dissolved hydrogen concentration in Japanese PWR plants. At low dose rate, the addition of 1.0 ppm methanol suppresses considerably the radiolysis of the coolant. At high dose rate, the addition of at least 10 ppm methanol is necessary to lower concentrations of the radiolytic oxidizing products. Concentrations of the radiolytic oxidizing products are determined not only by the scavenging of the OH radical but also by secondary reactions. In the presence of fast neutron irradiation, methanol acts to decompose the radiolytic oxidizing products. The fact that steady-state concentrations of the final organic products depend on dose rate means that complicated secondary reactions contribute to the decomposition of methanol. The major final organic product is formed through a reaction of ethylene glycol with OH. Methanol addition may have the same effect as ethylene glycol addition, and radiation chemical reactions of ethylene glycol systems should be elucidated in future.

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Influence of Dissolved Hydrogen on Oxide Film and PWSCC of Alloy 600 in PWR Primary Water.

Cited by 16 publications

References 4 publications

Influence of Dissolved Hydrogen on Structure of Oxide Film on Alloy 600 Formed in Primary Water of Pressurized Water Reactors

Influence of Dissolved Hydrogen on Structure of Oxide Film on Alloy 600 Formed in Primary Water of Pressurized Water Reactors

Influence of dissolved oxygen concentration on the oxide film formed on Alloy 690 in high temperature water

Numerical Simulation on Effect of Methanol Addition on Coolant Radiolysis in Pressurized Water Reactor

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