Microstructural Degradation of UN and UN-UO2 Composites in Hydrothermal Oxidation Conditions

Jennifer K. Watkins; Darryl P. Butt; Brian J. Jaques

Microstructural Degradation of UN and UN-UO₂ Composites in Hydrothermal Oxidation Conditions

Jennifer K. Watkins, Darryl P. Butt, Brian J. Jaques

Micron School of Materials Science and Engineering

Research output: Contribution to journal › Article › peer-review

Abstract

The degradation behavior in high pressure water of UN and UN + (5–10 w%) UO ₂ monolithic pellets fabricated from UN synthesized via a hydride-dehydride-nitride thermal process was investigated. Sintered pellets (>90% theoretical density) were subjected to hydrothermal oxidation in a water-filled static autoclave at temperatures ranging from 250 to 350 ° C and pressures to 16.5 MPa. Phase characterization and microstructural and chemical analysis was performed on the resulting corrosion products using X-ray diffraction (XRD), scanning electron microscopy (SEM) coupled with energy dispersive spectroscopy (EDS). The results of this screening study show that grain boundary attack and spallation is the primary degradation mechanism in hydrothermal oxidation conditions. The results also suggest the corrosion rate is higher in UN and UN-UO ₂ with higher starting oxygen content.

Original language	American English
Journal	Journal of Nuclear Materials
State	Published - 1 May 2019

Keywords

advanced technology fuel
hydrothermal degradation
nuclear fuel
uranium mononitride

EGS Disciplines

Materials Science and Engineering

Access to Document

https://doi.org/10.1016/j.jnucmat.2019.02.027

Cite this

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title = "Microstructural Degradation of UN and UN-UO2 Composites in Hydrothermal Oxidation Conditions",

abstract = " The degradation behavior in high pressure water of UN and UN + (5–10 w%) UO 2 monolithic pellets fabricated from UN synthesized via a hydride-dehydride-nitride thermal process was investigated. Sintered pellets (>90% theoretical density) were subjected to hydrothermal oxidation in a water-filled static autoclave at temperatures ranging from 250 to 350 ° C and pressures to 16.5 MPa. Phase characterization and microstructural and chemical analysis was performed on the resulting corrosion products using X-ray diffraction (XRD), scanning electron microscopy (SEM) coupled with energy dispersive spectroscopy (EDS). The results of this screening study show that grain boundary attack and spallation is the primary degradation mechanism in hydrothermal oxidation conditions. The results also suggest the corrosion rate is higher in UN and UN-UO 2 with higher starting oxygen content.",

keywords = "advanced technology fuel, hydrothermal degradation, nuclear fuel, uranium mononitride",

author = "Watkins, {Jennifer K.} and Butt, {Darryl P.} and Jaques, {Brian J.}",

note = "Watkins, Jennifer K.; Butt, Darryl P.; and Jaques, Brian J. (2019). {"}Microstructural Degradation of UN and UN-UO2 Composites in Hydrothermal Oxidation Conditions{"}. Journal of Nuclear Materials, 518, 30-40. https://doi.org/10.1016/j.jnucmat.2019.02.027",

year = "2019",

month = may,

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language = "American English",

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TY - JOUR

T1 - Microstructural Degradation of UN and UN-UO2 Composites in Hydrothermal Oxidation Conditions

AU - Watkins, Jennifer K.

AU - Butt, Darryl P.

AU - Jaques, Brian J.

N1 - Watkins, Jennifer K.; Butt, Darryl P.; and Jaques, Brian J. (2019). "Microstructural Degradation of UN and UN-UO2 Composites in Hydrothermal Oxidation Conditions". Journal of Nuclear Materials, 518, 30-40. https://doi.org/10.1016/j.jnucmat.2019.02.027

PY - 2019/5/1

Y1 - 2019/5/1

N2 - The degradation behavior in high pressure water of UN and UN + (5–10 w%) UO 2 monolithic pellets fabricated from UN synthesized via a hydride-dehydride-nitride thermal process was investigated. Sintered pellets (>90% theoretical density) were subjected to hydrothermal oxidation in a water-filled static autoclave at temperatures ranging from 250 to 350 ° C and pressures to 16.5 MPa. Phase characterization and microstructural and chemical analysis was performed on the resulting corrosion products using X-ray diffraction (XRD), scanning electron microscopy (SEM) coupled with energy dispersive spectroscopy (EDS). The results of this screening study show that grain boundary attack and spallation is the primary degradation mechanism in hydrothermal oxidation conditions. The results also suggest the corrosion rate is higher in UN and UN-UO 2 with higher starting oxygen content.

AB - The degradation behavior in high pressure water of UN and UN + (5–10 w%) UO 2 monolithic pellets fabricated from UN synthesized via a hydride-dehydride-nitride thermal process was investigated. Sintered pellets (>90% theoretical density) were subjected to hydrothermal oxidation in a water-filled static autoclave at temperatures ranging from 250 to 350 ° C and pressures to 16.5 MPa. Phase characterization and microstructural and chemical analysis was performed on the resulting corrosion products using X-ray diffraction (XRD), scanning electron microscopy (SEM) coupled with energy dispersive spectroscopy (EDS). The results of this screening study show that grain boundary attack and spallation is the primary degradation mechanism in hydrothermal oxidation conditions. The results also suggest the corrosion rate is higher in UN and UN-UO 2 with higher starting oxygen content.

KW - advanced technology fuel

KW - hydrothermal degradation

KW - nuclear fuel

KW - uranium mononitride

UR - https://scholarworks.boisestate.edu/mse_facpubs/414

UR - https://doi.org/10.1016/j.jnucmat.2019.02.027

M3 - Article

SN - 0022-3115

JO - Journal of Nuclear Materials

JF - Journal of Nuclear Materials

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