Numerical analysis of the galvanic coupling in the shadow corrosion of zirconium alloy

Buttin, Paul; Malki, B.; Barbéris, Pierre; Baroux, B.

doi:10.1016/j.jnucmat.2011.11.002

Cited by 6 publications

(15 citation statements)

References 18 publications

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“…e system geometry adopted in this work is fashioned after Lysell's electrochemical mechanism of SC where a platinum CE is electrically connected to a Zircaloy anode via an electrolyte [7] as depicted in Figure 1. e electrolyte occupies a distance d between the two opposing electrodes.…”

Section: Model Geometry and Boundary Conditionsmentioning

confidence: 99%

“…where j is the current density and σ is the electrolyte conductivity [7]. e mesh and boundary conditions used in the model are as shown in Figure 3.…”

Section: Model Geometry and Boundary Conditionsmentioning

confidence: 99%

“…(2) coupling of the two materials is via ionic transport in the coolant in the gap, which is aided by the potential difference between the two metals, and the transport of species under their concentration gradients; and (3) radiolysis is required for the hypothesized electrochemical mechanism to function, as it ensures that a minimum concentration of radiolytic species is present. SC has been adjudged as a phenomenon peculiar only to BWRs [6], and the results of experiments at the Massachusetts Institute of Technology (MIT) support the galvanic coupling paradigm as the cause of SC [7]. SC develops only when a counter-electrode (CE) consisting of a nobler metal than the Zircaloy is used, and the thickness of the oxide layer formed decreases as the distance between electrodes rises.…”

Section: Introductionmentioning

confidence: 99%

“…e MIT experiments have been used as a reference standard of validation for studies involving SC in commercial reactors [7]. e experiments revealed that with a 0.5 mm gap between Zircaloy-2 (anode) and platinum (cathode), an oxide layer of 20 µm was developed on the surface of Zircaloy-2 for corrosion lasting 1166 hours.…”

Section: Introductionmentioning

confidence: 99%

“…e experiments revealed that with a 0.5 mm gap between Zircaloy-2 (anode) and platinum (cathode), an oxide layer of 20 µm was developed on the surface of Zircaloy-2 for corrosion lasting 1166 hours. Factors impacting shadow corrosion in a BWR environment with platinum as the CE were explored using the MIT standard in a modeling study of the galvanic coupling process in a BWR environment [7]. It was shown that regardless of the nature of the CE, the same oxide thickness could be achieved as long as it was made of a metal nobler than Zircaloys.…”

Section: Introductionmentioning

confidence: 99%

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Investigation of Oxidation and Counter-Oxidation in a One-Quarter Circular Geometry due to Shadow Corrosion

Enivweru

Wang

Ayodeji

2022

Science and Technology of Nuclear Installations

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To optimize fission fuel and protect cladding integrity, this work investigates shadow corrosion in a one-fourth circular electrode geometry. The anodic corrosion of Zircaloy-2 (Zry-2) was investigated in a circular geometry electrode configuration under reactor operating conditions. The impact of gamma and neutron radiations on water conductivity and shadow corrosion was examined under two different cathodes. This work also investigates the effect of current exchange density and the cathodic Tafel coefficient on the cathodic current. Using COMSOL Multiphysics 5.2, the Laplace equation was solved to obtain the electrostatic potential and current density distributions in the studied domain. When the distance d between the anode (Zry-2) and cathode (platinum/nickel) is ≤0.5 mm, it was observed that a uniform oxide layer of thickness 20 µm grew on the smooth internal surface of Zry-2 for corrosion lasting 1166 h. When d > 0.5 mm, the oxide thickness falls in a manner dictated by the degree of dissociation α of the electrolyte. At a cladding gap of 0.08 mm, a radiation-enhanced uniform corrosion rate of 2.405 10−1 mmpy was obtained for Zry-2. This value is 142 times greater than that obtained at room temperature in the absence of radiation. It was also observed that the corrosion rate falls at higher cladding gaps, and the rate of change depends on the degree of dissociation. Other phenomena such as the dynamics of shadow corrosion under varying electrode separation and electrolyte conductivities, as well as extensive evaluation of critical fuel cladding parameters, are presented in this work.

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Section: Model Geometry and Boundary Conditionsmentioning

confidence: 99%

“…where j is the current density and σ is the electrolyte conductivity [7]. e mesh and boundary conditions used in the model are as shown in Figure 3.…”

Section: Model Geometry and Boundary Conditionsmentioning

confidence: 99%