Irradiation effects on the fracture properties of UO2 fuels studied by micro-mechanical testing

Henry, Ronan; Zacharie-Aubrun, I.; Blay, Thierry; Tarisien, N.; Chalal, Smail; Iltis, X.; Gatt, Jean-Marie; Langlois, Cyril; Meille, Sylvain

doi:10.1016/j.jnucmat.2020.152179

Cited by 18 publications

(15 citation statements)

References 19 publications

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“…4,5 Experimental measurements on grain boundaries are common on nonradioactive materials such as metals or yttria stabilized zirconia (YSZ). 6,7 Concerning UO2, far fewer results are available, 10 but our Institute recently proposed the first measurements of formation energies and toughness of grain boundaries in UO 2 . [8][9][10] Numerical simulations are a good alternative to this small amount of experimental data.…”

Section: Introductionmentioning

confidence: 99%

Molecular dynamics study of UO₂ symmetric tilt grain boundaries around [001] axis

2021

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Molecular dynamics and CRG empirical potential are used in this work to study the symmetrical tilt grain boundaries around the [001] axis in UO2. The analysis of atomic structures obtained by simulation shows excellent agreement with the Read and Schokley model (Read WT, Shockley W. Dislocation Models of Crystal Grain Boundaries. Physical Review. 1950;78:275) predicting the existence of regular dislocations in these grain boundaries. We calculated their energy of formation and cleavage as well as the energy of formation of Schottky defects and incorporation of xenon and krypton atoms in their proximity. This allowed us to determine how these properties evolve for this series of grain boundaries presenting similar geometric characteristics, as a function of the misorientation angle. In addition, the boundary between small and large misorientation grain boundaries has been determined around 20°, close to the value of 15° reported in literature.

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Section: Introductionmentioning

confidence: 99%

Molecular dynamics study of UO₂ symmetric tilt grain boundaries around [001] axis

2021

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“…The second type of specimens is UO 2 irradiated in PWR at a 34 GWd/tU average burn-up and is referred as to I UO 2 . This last fuel has a Cr 2 O 3 doping, which allows a considerable increase in grain size during sintering but has almost no influence on the mechanical properties measured inside the grains [10]. Indeed, Cr 2 O 3 doping represents very small quantities (less than 0.1%wt).…”

Section: Methodsmentioning

confidence: 99%

“…Specimens without initial notch may therefore be slightly influence by ion implantation, which cannot be avoided at the notch of specimens containing an initial notch. Experimental studies demonstrated that ion implantation has almost no influence on the measured UO2 fracture toughness [9,10], which may not always be the case for other materials [41][42][43]. A detailed description of the manufacturing process can be found in [9] and [10].…”

Section: Specimen Preparationmentioning

confidence: 99%

“…The recent development of micromechanical tests on irradiated fuels has given access to their local fracture properties [9,10], employing a micro-cantilever bending method initially developped by Di Maio et al [11]. However, because of the micrometric dimensions of the specimens, scale effects are observed on the fracture stress compared to larger specimens.…”

Section: Introductionmentioning

confidence: 99%

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UO2 micron scale specimen fracture: Parameter identification and influence of porosities

Doitrand

Henry

Zacharie-Aubrun

et al. 2020

Theoretical and Applied Fracture Mechanics

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Bending of micron-scale cantilevers with or without initial notch is simulated by finite element and their fracture is assessed using either the coupled criterion or a cohesive zone model.The fracture toughness and strength of UO 2 single grain specimens with several crystal orientations are determined by means of inverse identification based on experimental tests at the micron-scale. Irradiation causes a decrease in fracture toughness from around 10 J/m 2 to around 5 J/m 2 , whereas the strength variation remains in the order of magnitude of the measurement uncertainty. Premature fracture may occur in presence of a pore provided it is located close enough to the specimen surface undergoing tension, the resulting failure force decreasing with increasing pore size. A network of small porosities located on the fracture surface induces a decrease in the failure force which magnitude mainly depends on the total surface fraction and on the porosity locations rather than on the porosity size.

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“…Recent advancements in the characterization instruments have enabled fundamental research that aims at local chemistry, mechanics, and microstructure near the interfaces 5 . High‐resolution electron microscopy in combination with focused ion beam technique was adopted for in situ measurement of element segregation at the grain boundary in spinel as well as interfacial fracture behavior in irradiated nuclear fuels 6,7 . Atomic force microscopy enabled local studies of the electronic, ionic, and heat transport across boundaries in graphene, lithium‐ion battery, and Al‐Cu alloys 8‐10 .…”

Section: Introductionmentioning

confidence: 99%

Shear wave generation by mode conversion in picosecond ultrasonics: Impact of grain orientation and material properties

Wang

Khafizov

2021

J Am Ceram Soc

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Picosecond ultrasonics has seen wide application in the investigation of interfaces in semiconductors and 3D imaging in biological systems. Shear ultrasonic waves are important for elastic constant and grain orientation measurement in ceramic materials. In this study, we investigate the impact of grain orientation and material's elastic properties on the generation efficiency of shear waves by mode conversion at a transducer thin film/substrate interface. The solution of acoustic wave equations suggests that crystal grain orientation has a strong impact on the generated shear wave amplitude. This dependence is found to be closely related to the magnitude of longitudinal component of wave displacements. The applicability of analytical model is validated by the experimental results from time‐domain Brillouin scattering. Moreover, material properties determine acoustic wave amplitudes based on the acoustic mismatch model and, particularly, large elastic anisotropy defined by Zener ratio favors strong shear waves. In the light of this analysis, several recommendations on suitable grain orientations and film materials are made to facilitate shear wave detection.

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Irradiation effects on the fracture properties of UO2 fuels studied by micro-mechanical testing

Cited by 18 publications

References 19 publications

Molecular dynamics study of UO₂ symmetric tilt grain boundaries around [001] axis

Molecular dynamics study of UO₂ symmetric tilt grain boundaries around [001] axis

UO2 micron scale specimen fracture: Parameter identification and influence of porosities

Shear wave generation by mode conversion in picosecond ultrasonics: Impact of grain orientation and material properties

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Irradiation effects on the fracture properties of UO2 fuels studied by micro-mechanical testing

Cited by 18 publications

References 19 publications

Molecular dynamics study of UO2 symmetric tilt grain boundaries around [001] axis

Molecular dynamics study of UO2 symmetric tilt grain boundaries around [001] axis

UO2 micron scale specimen fracture: Parameter identification and influence of porosities

Shear wave generation by mode conversion in picosecond ultrasonics: Impact of grain orientation and material properties

Contact Info

Product

Resources

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Molecular dynamics study of UO₂ symmetric tilt grain boundaries around [001] axis

Molecular dynamics study of UO₂ symmetric tilt grain boundaries around [001] axis