Restructuring in high burnup UO2 studied using modern electron microscopy

Gerczak, Tyler J.; Parish, Chad M.; Edmondson, Philip D.; Baldwin, Charles A.; Terrani, Kurt A.

doi:10.1016/j.jnucmat.2018.05.077

Title: Restructuring in high burnup UO₂ studied using modern electron microscopy

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Abstract

Modern electron microscopy techniques were used to conduct a thorough study of an irradiated urania fuel pellet microstructure to attempt at an understanding of high burnup structure formation in this material. The fuel was irradiated at low power to high burnups in a light water reactor, proving ideal for this purpose. Examination of grain size and orientation with strict spatial selectivity across the fuel pellet radius allowed for capturing the progression of the restructuring process, from its onset to full completion. Based on this information, the polygonization mechanism was shown to be responsible for restructuring, involving formation of low-angle grain boundaries with their initiation occurring at the original high-angle grain boundaries of the as-fabricated pellet and at the gas bubble-matrix interfaces. As a result, the low-angle character of boundaries between the subdivided grains disappeared in the fully developed high burnup structure, likely due to creep deformation in the pellet.

Authors:

^[1];

^[1]; Baldwin, Charles A. ^[1];

^[1]

Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

Publication Date:: Sat Jun 02 00:00:00 EDT 2018

Research Org.:: Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

Sponsoring Org.:: USDOE

OSTI Identifier:: 1460228

Alternate Identifier(s):: OSTI ID: 1548154

Grant/Contract Number:: AC05-00OR22725

Resource Type:: Accepted Manuscript

Journal Name:: Journal of Nuclear Materials

Additional Journal Information:: Journal Volume: 509; Journal Issue: C; Journal ID: ISSN 0022-3115

Publisher:: Elsevier

Country of Publication:: United States

Language:: English

Subject:: 11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS

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                    Gerczak, Tyler J., Parish, Chad M., Edmondson, Philip D., Baldwin, Charles A., and Terrani, Kurt A. Restructuring in high burnup UO2 studied using modern electron microscopy.  United States: N. p., 2018. 
Web.  doi:10.1016/j.jnucmat.2018.05.077.

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                    Gerczak, Tyler J., Parish, Chad M., Edmondson, Philip D., Baldwin, Charles A., & Terrani, Kurt A. Restructuring in high burnup UO2 studied using modern electron microscopy.  United States.  https://doi.org/10.1016/j.jnucmat.2018.05.077

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                    Gerczak, Tyler J., Parish, Chad M., Edmondson, Philip D., Baldwin, Charles A., and Terrani, Kurt A. Sat .  
"Restructuring in high burnup UO2 studied using modern electron microscopy".  United States.  https://doi.org/10.1016/j.jnucmat.2018.05.077.  https://www.osti.gov/servlets/purl/1460228.

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@article{osti_1460228,

  title        = {Restructuring in high burnup UO2 studied using modern electron microscopy},

  author       = {Gerczak, Tyler J. and Parish, Chad M. and Edmondson, Philip D. and Baldwin, Charles A. and Terrani, Kurt A.},

  abstractNote = {Modern electron microscopy techniques were used to conduct a thorough study of an irradiated urania fuel pellet microstructure to attempt at an understanding of high burnup structure formation in this material. The fuel was irradiated at low power to high burnups in a light water reactor, proving ideal for this purpose. Examination of grain size and orientation with strict spatial selectivity across the fuel pellet radius allowed for capturing the progression of the restructuring process, from its onset to full completion. Based on this information, the polygonization mechanism was shown to be responsible for restructuring, involving formation of low-angle grain boundaries with their initiation occurring at the original high-angle grain boundaries of the as-fabricated pellet and at the gas bubble-matrix interfaces. As a result, the low-angle character of boundaries between the subdivided grains disappeared in the fully developed high burnup structure, likely due to creep deformation in the pellet.},

  doi          = {10.1016/j.jnucmat.2018.05.077},

  journal      = {Journal of Nuclear Materials},

  number       = C,

  volume       = 509,

  place        = {United States},

  year         = {Sat Jun 02 00:00:00 EDT 2018},

  month        = {Sat Jun 02 00:00:00 EDT 2018}

}

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Title: Restructuring in high burnup UO2 studied using modern electron microscopy

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Title: Restructuring in high burnup UO₂ studied using modern electron microscopy