A model for the influence of steel corrosion products on nuclear fuel corrosion under permanent disposal conditions

Wu, Linda; Beauregard, Yannick; Qin, Z.; Rohani, Sohrab; Shoesmith, David W.

doi:10.1016/j.corsci.2012.04.027

Cited by 20 publications

(14 citation statements)

References 35 publications

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“…Effect of H 2 .-The previous 1D model 34,49 showed that H 2 can completely suppress UO 2 corrosion on a planar fuel surface. The critical [H 2 ] required for the complete inhibition of corrosion, [H 2 ] crit , was calculated to be ∼0.19 μmol L −1 for CANDU fuel with an age of 1000 years.…”

Section: Resultsmentioning

confidence: 98%

Modeling the Radiolytic Corrosion of Fractured Nuclear Fuel under Permanent Disposal Conditions

Liu

Qin

et al. 2014

J. Electrochem. Soc.

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A two-dimensional model has been developed to simulate the corrosion of nuclear fuel pellets under permanent waste disposal conditions in a steel vessel with a corrosion-resistant copper shell. The primary emphasis was on the corrosion behavior within cracks with various dimensions. It was shown that a simplified α-radiolysis model which only accounts for the radiolytic production of H 2 O 2 and H 2 provides a reasonably accurate simulation and is a time-efficient alternative to the use of a model including a full α-radiolysis reaction set. Both radiolytic H 2 O 2 and H 2 can accumulate inside the cracks. However, the [H 2 O 2 ] is regulated by its reaction with UO 2 to cause corrosion and especially its decomposition to O 2 and H 2 O. This leads to [H 2 ] much greater than [H 2 O 2 ] within the cracks. The critical [H 2 ], [H 2 ] crit , required to completely suppress corrosion has been calculated for various crack widths and depths. The maximum [H 2 ] crit is only ∼ 12 times that required on a planar surface irrespective of the dimensions of the crack. The build up of H 2 within cracks is effectively a shift to more reducing conditions. As a consequence, the redox conditions within cracks begin to decouple from the external redox conditions. This makes the fuel corrosion process at these locations less sensitive than might be expected to the influences of the H 2 and Fe 2+ produced by corrosion of the steel vessel.

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Section: Resultsmentioning

confidence: 98%

Modeling the Radiolytic Corrosion of Fractured Nuclear Fuel under Permanent Disposal Conditions

Liu

Qin

et al. 2014

J. Electrochem. Soc.

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“…To determine the overall inuence of these many reactions we have developed a model to determine the inuence of steel corrosion products on the alpha (a) radiolytic corrosion of spent nuclear fuel within a failed waste container. [28][29][30] The key reactions incorporated in this model are illustrated in Fig. 2 and include: (1) a complete reaction set for the a-radiolysis Fig.…”

Section: Faraday Discussionmentioning

confidence: 99%

The influence of hydrogen peroxide and hydrogen on the corrosion of simulated spent nuclear fuel

Razdan

Shoesmith

2015

Faraday Discuss.

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The synergistic influence between H(2)O(2) and H(2) on the corrosion of SIMFUEL (simulated spent nuclear fuel) has been studied in solutions with and without added HCO(3)(-)/CO(3)(2-). The response of the surface to increasing concentrations of added H(2)O(2) was monitored by measuring the corrosion potential in either Ar or Ar/H(2)-purged solutions. Using X-ray photoelectron spectroscopy it was shown that the extent of surface oxidation (U(V) + U(VI) content) was directly related to the corrosion potential. Variations in corrosion potential with time, redox conditions, HCO(3)(-)/CO(3)(2-) concentration, and convective conditions showed that surface oxidation induced by H(2)O(2) could be reversed by reaction with H(2), the latter reaction occurring dominantly on the noble metal particles in the SIMFUEL. For sufficiently large H(2)O(2) concentrations, the influence of H(2) was overwhelmed and irreversible oxidation of the surface to U(VI) occurred. Subsequently, corrosion was controlled by the chemical dissolution rate of this U(VI) layer.

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“…18,19 An additional feature of the model, related to the movement of U species, is the ability of dissolved U VI to escape to the bulk groundwater on reaching the pore mouth. This can be described by equation (11) n : D i +C i (z~d)~a i (C bi {C i ) (11) where d is the pore depth, and a i and C bi are the mass transport coefficient and bulk concentration of species i, respectively. The values of a i are assumed sufficiently large that species reaching the pore mouth would escape to the bulk solution, thereby maintaining a constant concentration at this location.…”

Section: Modelmentioning

confidence: 99%

Modelling development of acidification within corroding sites on spent fuel surfaces

Qin

Cheong

Keech

et al. 2014

Corrosion Engineering, Science and Technology

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A model has been developed to predict whether the development of acidity is feasible within actively corroding sites on spent nuclear fuel (UO 2 ) surfaces inside a failed nuclear waste container. The model simulations demonstrate that the build-up of acidity is possible within flaws and pores in a corroded UO 2 surface, providing the separation of anodes and cathodes occurs. The extent to which the pH can be depressed is determined by the dissolution rate of the fuel, the dimensions of the defect, the local redox conditions which determine the corrosion potential, and the fraction of the fuel surface that is reactive. Based on the anticipated redox conditions established radiolytically in a failed container it is shown that a suppression of the pH sufficient to accelerate dissolution (pH#5) is very unlikely.

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A model for the influence of steel corrosion products on nuclear fuel corrosion under permanent disposal conditions

Cited by 20 publications

References 35 publications

Modeling the Radiolytic Corrosion of Fractured Nuclear Fuel under Permanent Disposal Conditions

Modeling the Radiolytic Corrosion of Fractured Nuclear Fuel under Permanent Disposal Conditions

The influence of hydrogen peroxide and hydrogen on the corrosion of simulated spent nuclear fuel

Modelling development of acidification within corroding sites on spent fuel surfaces

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