Simulation of hydrogen embrittlement in zirconium alloys under stress and temperature gradients

Varias, A G; Massih, Ali R

doi:10.1016/s0022-3115(99)00286-x

Cited by 75 publications

(33 citation statements)

References 26 publications

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“…Fracture is attributed to the contribution of several factors, such as (1) compressive stresses in the oxide due to volumetric expansion during oxidation (Pillar-Bedworth ratio of 1.56), 2 (2) tensile stresses in the oxide layer due to thermal and irradiation induced expansion on the fuel side, and (3) dynamic embrittlement caused by hydride precipitation. [8][9][10][11][12] Due to the highly complex and synergistic nature of corrosion kinetics, with coupled oxygen/hydrogen transport, diffusion/ reaction kinetics, temperature effects, and complex oxide microstructures, to name but a few, a multipronged approach that includes modeling as an essential element must be adopted to improve our understanding of the process.…”

Section: Zr Smentioning

confidence: 99%

Integrated Computational Modeling of Water Side Corrosion in Zirconium Metal Clad Under Nominal LWR Operating Conditions

Aryanfar

Thomas

Ven

et al. 2016

JOM

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A mesoscopic chemical reaction kinetics model to predict the formation of zirconium oxide and hydride accumulation light-water reactor (LWR) fuel clad is presented. The model is designed to include thermodynamic information from ab initio electronic structure methods as well as parametric information in terms of diffusion coefficients, thermal conductivities and reaction constants. In contrast to approaches where the experimentally observed time exponents are captured by the models by design, our approach is designed to be predictive and to provide an improved understanding of the corrosion process. We calculate the time evolution of the oxide/metal interface and evaluate the order of the chemical reactions that are conducive to a t 1/3 dependence. We also show calculations of hydrogen cluster accumulation as a function of temperature and depth using spatially dependent cluster dynamics. Strategies to further cohesively integrate the different elements of the model are provided.

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Section: Zr Smentioning

confidence: 99%

Integrated Computational Modeling of Water Side Corrosion in Zirconium Metal Clad Under Nominal LWR Operating Conditions

Aryanfar

Thomas

Ven

et al. 2016

JOM

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“…the energy required per unit crack advance, and the maximum cohesive traction are given by the following relations: K . Also hr σ is hydride fracture strength and M σ is equal to three times the yield stress of the metal [15]. Note that the elastic-plastic behavior of the metal has been considered in the derivation of de-cohesion constitutive relations, in order to accurately predict the strong effect of hydrostatic stress on hydrogen diffusion.…”

Section: Hydride Induced Embrittlement and Fracture Modelmentioning

confidence: 99%

“…However, the heat transfer process within a nuclear reactor core leads to the development of temperature gradient in the fuel cladding and significantly affects material deterioration. A mathematical model, which takes into account all processes (i)-(iv) as well as hydride fracture for the simulation of crack growth, has been developed by Varias and Massih [15], [17]. The model is based on the thermodynamic theory of irreversible processes and takes into account hydrogen thermal transport.…”

Section: Introductionmentioning

confidence: 99%

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Hydride-Induced Embrittlement in Metals — Stress and Temperature Effects

Varias

Massih

2003

IUTAM Symposium on Field Analyses for Determination of Material Parameters — Experimental and Numerical Aspects

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A robust mathematical model for the hydrogen embrittlement of hydride forming metals has been developed. The model takes into account the coupling of the operating physical processes, namely: (i) hydrogen diffusion, (ii) hydride precipitation, (iii) non-mechanical energy flow, and (iv) hydride/solid-solution deformation. Crack growth is simulated by using a new version of de-cohesion model with time-dependent energy of de-cohesion due to the gradual process of hydride formation. Zircaloy-2 hydrogen embrittlement and fracture initiation have been studied by using a finite element implementation of the model. Delayed hydride cracking has been considered in two configurations: (i) a semi-infinite crack, under mode-I K-field dominance and constant temperature, and (ii) a cracked plate, under tensile stress and temperature gradient. The initial and boundary conditions, in case (ii), are those encountered in the fuel cladding of boiling water reactors, during operation, and lead to loss of K-field dominance soon after the application of loading. The numerical simulation predicts hydride precipitation at some distance from the crack tip. The near-tip hydride platelets fracture, when the remote loading is sufficiently strong, and leave behind ligaments, which are stretched plastically, in agreement with experimental observations. The numerical results on hydride size, incubation period and crack growth velocity are compared with experimental data.Further development of the model should be combined with accurate experimental determination of the mechanical and thermal properties of the hydrides.

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“…There are several experimental studies of thermal transport of mass in metals, for example of hydrogen, deuterium and carbon in bcc -Fe and V, in fcc Ni, Co and Pd and in hcp Zr (e.g. [1], [3]). …”

Section: Introductionmentioning

confidence: 99%

On the Coupling of Mass Diffusion and Non-Mechanical Energy Flow in Metals under Finite Deformation~!2008-03-24~!2008-06-02~!2008-06-12~!

Varias¹

2008

TOMECHJ

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Abstract:The governing equation of non-mechanical energy flow in metals, undergoing finite deformation, is presented. The coupling of non-mechanical energy flow, mass diffusion and metal elastic-plastic deformation is rigorously taken into account. The analysis is particularly useful in cases of diffusion-driven degradation mechanisms ahead of stationary cracks or cracks initiating growth, under temperature variations.

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Simulation of hydrogen embrittlement in zirconium alloys under stress and temperature gradients

Cited by 75 publications

References 26 publications

Integrated Computational Modeling of Water Side Corrosion in Zirconium Metal Clad Under Nominal LWR Operating Conditions

Integrated Computational Modeling of Water Side Corrosion in Zirconium Metal Clad Under Nominal LWR Operating Conditions

Hydride-Induced Embrittlement in Metals — Stress and Temperature Effects

On the Coupling of Mass Diffusion and Non-Mechanical Energy Flow in Metals under Finite Deformation~!2008-03-24~!2008-06-02~!2008-06-12~!

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