Grain growth in pure and titania-doped uranium dioxide

Amato, I.; Colombo, R.L.; Balzari, A.Petruccioli

doi:10.1016/0022-3115(66)90166-8

Cited by 29 publications

(8 citation statements)

References 14 publications

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“…However, appreciable increase of micro hardness can be found in 1600-doped sample as compared to the 1500-doped sample. This is consistent with the previous literature in which hyper-stoichiometric UO 2 displayed a higher hardness than stoichiometric UO 2 [11,53]. Further increase in sintering temperature to 1700 °C, as revealed by Fig.…”

Section: Mechanical and Thermal Properties Of The Sps Sintered Tio 2 supporting

confidence: 93%

“…The significant shift of the (111) diffraction peak towards stoichiometric UO 2 from the oxygen-enriched composition indicates that SPS process enables the control of sintered pellets' stoichiometry from the highly reducing graphite environment. The stoichiometric control of fuel pellets sintered by SPS without pre-or post-treatments was also reported in recent literature [18] [11]. Further increases in the sintering temperature up to 1700 °C, the (111) peak shifts back aligned with that of the 1500-doped pellets, indicating a similar stoichiometry for both samples.…”

Section: Fuel Chemistry and Stoichiometry By Xrd And Raman Analysissupporting

confidence: 81%

“…To manipulate microstructure and obtain larger grain-sized UO 2 fuel pellets, oxide dopants were used as sintering additives [5][6][7][8][9][10] including TiO 2 [11,12], Cr 2 O 3 [13], Al 2 O 3 [14], and MgO [15] were studied with the focus on their effects on fission gas retention and fuel swelling in-pile performance. Unique features of oxide-doped fuels include greatly-enlarged grain size, as large as 100 µm, significantly larger than that of standard fuel (10-15 µm).…”

Section: Introductionmentioning

confidence: 99%

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TiO2 doped UO2 fuels sintered by spark plasma sintering

Yao¹,

Scott²,

Xin³

et al. 2016

Journal of Nuclear Materials

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UO 2 fuels doped with oxide additives Cr 2 O 3 and TiO 2 display larger grain size, improving fission product retention capability and thus accident tolerance. Spark plasma sintering (SPS) was applied to consolidate TiO 2 -doped UO 2 fuel pellets with 0.5 wt % dopant concentration, above its solubility, in order to induce eutectic phase formation and promote sintering kinetics. The largest grain achieved is up to 80 µm by sintering at 1700 °C for 20 mins, and liquid U-Ti-O eutectic phase occurs at the triple junction of grain boundaries and significantly improves grain growth during sintering. The oxide additive also impedes the reduction of the initial hyperstoichiometric fuel powders to more stoichiometric pellets upon SPS. Thermal-mechanical properties of the sintered doped pellets including thermal conductivity and hardness are measured and compared with undoped pellets. The enlarged grain size (80 µm) and densification within short sintering duration highlight the immense possibility of SPS in fabricating large grain UO 2 fuel pellets to improve fuel performance.

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Section: Mechanical and Thermal Properties Of The Sps Sintered Tio 2 supporting

confidence: 93%

Section: Fuel Chemistry and Stoichiometry By Xrd And Raman Analysissupporting

confidence: 81%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

TiO2 doped UO2 fuels sintered by spark plasma sintering

Yao¹,

Scott²,

Xin³

et al. 2016

Journal of Nuclear Materials

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“…A similar phenomenon has been observed for bulk‐UO 2 . Compared with pure UO 2 , titania‐doped UO 2 is not only found to have faster grain growth rate, but also higher activation energy.…”

Section: Resultsmentioning

confidence: 99%

Grain growth and pore coarsening in dense nano‐crystalline UO_2+x fuel pellets

Yao

Yun

et al. 2017

J Am Ceram Soc

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Dense nano‐sized UO2+x pellets are synthesized by spark plasma sintering with controlled stoichiometries (UO2.03 and UO2.11) and grain sizes (~100 nm), and subsequently isothermally annealed to study their effects on grain growth kinetics and microstructure stability. The grain growth kinetics is determined and analyzed focusing on the interaction between grain boundary migration, pore growth, and coalescence. Grains grow much bigger in nano‐sized UO2.11 than UO2.03 upon thermal annealing, consistent with the fact that hyper‐stoichiometric UO2+x is beneficial for sintering due to enhanced U ion diffusion from excessive O ion interstitials. The activation energies of the grain growth for UO2.03 and UO2.11 are determined as ~1.0 and ~2.0 eV, respectively. As compared with the micrometer‐sized UO2 in which volumetric diffusion dominates the grain coarsening with an activation energy of ~3.0 eV, the enhanced grain growth kinetics in nano‐sized UO2+x suggests that grain boundary diffusion controls grain growth. The higher activation energy of more hyper‐stoichiometric nano‐sized UO2.11 may be attributed to the excessive O interstitials pinning grain boundary migration.

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“…The most effective way was adding additives to the UO 2 matrix. The common additives included Cr 2 O 3 (Bourgeois et al, 2001;Arborelius et al, 2006;Yang et al, 2012), TiO 2 (Amato et al, 1966;Ainscough et al, 1974;Yao et al, 2016), Nb 2 O 5 (Killeen, 1975;Song et al, 1994), Al 2 O 3 (Oh et al, 2014;Une et al,2000) and MgO (Sawbridge et al, 1980). Recently, Yang et al (2012) (Che et al, 2018).…”

Section: Introductionmentioning

confidence: 99%

Preparation and Characterization of Large Grain UO2 for Accident Tolerant Fuel

Zhong

Gao

et al. 2021

Front. Mater.

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Large grain UO2 is considered as an accident tolerant fuel with great application potential due to its competitive advantage of good fission gas retention. In this paper, the influence of preparation parameters such as sintering atmosphere, mixing process, powder pretreatment and grain growth additives on the grain size of UO2 is systematically studied. The result shows that the factors mentioned above have different effects on the grain size of UO2. The grain growth of UO2 pellet sintered in oxidizing atmosphere is better than those in reducing atmosphere. The wet mixing process has a significant advantage over the dry mixing process. In addition, the powder pretreatment has little effect on grain growth while the influence of additives plays the main role. Large grain UO2 pellets with uniform grain size up to 150 μm are successfully prepared. Finally, the thermo-physical properties of the pellets are investigated.

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Grain growth in pure and titania-doped uranium dioxide

Cited by 29 publications

References 14 publications

TiO2 doped UO2 fuels sintered by spark plasma sintering

TiO2 doped UO2 fuels sintered by spark plasma sintering

Grain growth and pore coarsening in dense nano‐crystalline UO_2+x fuel pellets

Preparation and Characterization of Large Grain UO2 for Accident Tolerant Fuel

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Grain growth in pure and titania-doped uranium dioxide

Cited by 29 publications

References 14 publications

TiO2 doped UO2 fuels sintered by spark plasma sintering

TiO2 doped UO2 fuels sintered by spark plasma sintering

Grain growth and pore coarsening in dense nano‐crystalline UO2+x fuel pellets

Preparation and Characterization of Large Grain UO2 for Accident Tolerant Fuel

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Grain growth and pore coarsening in dense nano‐crystalline UO_2+x fuel pellets