Helium behavior in UO2 polycrystalline disks

Guilbert, S.; Sauvage, Thierry; Erramli, H.; Barthe, M.F.; Desgardin, P.; Blondiaux, G.; Corbel, C.; Piron, J.P.

doi:10.1016/s0022-3115(03)00212-5

Cited by 29 publications

(32 citation statements)

References 21 publications

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“…• the precipitation of helium in the material structure, according to helium behavior in UO 2 study at a concentration of 1 at.% presented in [23], a Indicates reference sample, as implanted and without annealing. • the effect of defect induced by ions implantation in the material.…”

Section: Thermal Diffusionmentioning

confidence: 99%

Helium thermal diffusion in a uranium dioxide matrix

Roudil

Deschanels

Trocellier

et al. 2004

Journal of Nuclear Materials

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Section: Thermal Diffusionmentioning

confidence: 99%

Helium thermal diffusion in a uranium dioxide matrix

Roudil

Deschanels

Trocellier

et al. 2004

Journal of Nuclear Materials

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“…Helium was introduced at the same depth as in the samples of Guilbert et al [3] but the implanted gas concentrations were 2.5 times lower. A depth profile of the implanted distribution is shown in Fig.…”

Section: Resultsmentioning

confidence: 99%

“…The observed craters have a depth nearing 2 µm corresponding to the depth at which the helium concentration peaks (see Fig.1). Finally, flaking effects were also induced by the deuteron microbeam used during the analysis of samples which were implanted with 3 He at a depth of ~1 µm for a maximal 3 He concentration of ~ 0.3 at.% [10,11], as shown in Fig. 5.…”

Section: Resultsmentioning

confidence: 99%

“…Guilbert et al [3] showed however that in a sample implanted at a maximum concentration of 1 at.% and at the same depth, the surface was largely exfoliated after an annealing stage at only 500°C. A major difference between these two studies lies in respective implanted helium concentrations.…”

Section: Discussionmentioning

confidence: 99%

“…The extreme embrittlement in this case is according to authors probably due to massive gas accumulation at the grain boundaries, which would act as low temperature trapping sites for gas atoms whereas they have been shown to constitute diffusion shortcuts at and above 800°C [2]. Guilbert et al [3] studied sintered uranium dioxide samples implanted with helium ions to a maximal concentration of ~ 1 at.% at a depth of 2 µm below the sample surface. They observed the flaking of large areas at the sample surface after annealing at 500°C for 1 hour.…”

Section: Introductionmentioning

confidence: 99%

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Surface Blistering and Flaking of Sintered Uranium Dioxide Samples under High Dose Gas Implantation and Annealing

Martin

Carlot²,

Desgardin

et al. 2012

DDF

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High helium contents will be generated within minor actinide doped uranium dioxide blankets which could be used in fourth generation reactors. In this framework, it is essential to improve our understanding of the type of damage which a pellet could incur as a result of extensive helium build-up. This paper is an attempt at tackling this issue. Sintered uranium dioxide disks have been implanted with helium ions then annealed at various temperatures. Above a concentration of 0.4 at.% and above 1000°C, optical images of the sample surface revealed swollen grains and extensive areas which have exfoliated. Nuclear reaction microanalyses and atomic force microscopy observations were performed to demonstrate that helium has substantially precipitated within the swollen grains. Massive precipitation of the gas leads under these conditions to sample surface blistering which appears to precede flaking. Deuterium ion irradiations have also been performed at ambient and a direct flaking of the sample surface was observed, but for this phenomenon to be observed required much higher doses than in the He study, indicating that temperature could be an essential ingredient for gas to migrate and cause extensive precipitation. Such phenomena could possibly lead to degradation of the fuel.

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Variation in the surface morphology of polycrystalline UO₂ powder induced by helium precipitation

Serizawa

Matsunaga²,

Shirasu

et al. 2013

Journal of Asian Ceramic Societies

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This report addresses the precipitation of helium in polycrystalline UO 2 , which deforms the morphology of the grains and their surfaces. The formation of intragranular gas bubbles by the diffused helium can adversely affect the sintering process of ceramic-type nuclear fuel pellets. Helium was injected into pulverized UO 2 particles at 1473 K by hot isostatic pressing (HIP). The specific surface area measured by volumetric gas adsorption instrument implied that small pores should exist on the as-helium-treated sample surface. Field-emission scanning electron microscopy observations showed that numerous shallow basins (approximately 500 nm in radius) with hexagonal fringe were formed on the surface. The basin resembles a ruptured blister whose lid has been forced open. SEM observations showed a uniform polygonal-shaped section of the gas bubble on the fracture surface; this implies that precipitated helium forms a negative crystal in the grain. These interesting results suggest the possibility that the rupture of the negative crystal formed in the vicinity of the surface is related to the formation of the basin with a hexagonal fringe.

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Helium behavior in UO2 polycrystalline disks

Cited by 29 publications

References 21 publications

Helium thermal diffusion in a uranium dioxide matrix

Helium thermal diffusion in a uranium dioxide matrix

Surface Blistering and Flaking of Sintered Uranium Dioxide Samples under High Dose Gas Implantation and Annealing

Variation in the surface morphology of polycrystalline UO₂ powder induced by helium precipitation

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Helium behavior in UO2 polycrystalline disks

Cited by 29 publications

References 21 publications

Helium thermal diffusion in a uranium dioxide matrix

Helium thermal diffusion in a uranium dioxide matrix

Surface Blistering and Flaking of Sintered Uranium Dioxide Samples under High Dose Gas Implantation and Annealing

Variation in the surface morphology of polycrystalline UO2 powder induced by helium precipitation

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Variation in the surface morphology of polycrystalline UO₂ powder induced by helium precipitation