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High-Temperature Oxidation of Zircaloy-4 in Steam and Steam-Hydrogen Environments.

NUREGCR4476

Publication Date	1986
Personal Author	Prater, J. T.; Courtright, E. L.
Page Count	31
Abstract	The oxidation kinetics of Zircaloy-4 in steam have been extended to 2400 C. The ZrO2 and alpha-Zr layers display parabolic growth behavior over the entire temperature range studied. A discontinuity in the oxidation kinetics at 1510 C causes rates to increase above those previously established by the Baker-Just relationship. This increase coincides with the tetragonal-to-cubic phase transformation in ZrO2-x. No additional discontinuity in the oxide growth rate was observed when the metal phase melted. The effects of temperature gradients were taken into account, and corrected values representative of near-isothermal conditions were computed. Oxide growth was also measured in various steam-hydrogen mixtures at 1565 C and 1815 C. Hydrogen concentrations up to 90 mol% had no effect on oxidation kinetics. The rate-controlling factor appears to be diffusion through the oxide layer.
Keywords	Oxidation Zircaloys Reaction kinetics Zirconium alloy zircaloy-4
Source Agency	Technical Information Center Oak Ridge Tennessee Nuclear Regulatory Commission
NTIS Subject Category	71N - Nonferrous Metals & Alloys 99F - Physical & Theoretical Chemistry 77H - Reactor Engineering & Nuclear Power Plants
Corporate Authors	Battelle Pacific Northwest Labs., Richland, WA.; Nuclear Regulatory Commission, Washington, DC. Office of Nuclear
Supplemental Notes	Sponsored by Nuclear Regulatory Commission, Washington, DC. Office of Nuclear Regulatory Research.
Document Type	Technical Report
Title Note	Technical rept.
NTIS Issue Number	198611

High-Temperature Oxidation of Zircaloy-4 in Steam and Steam-Hydrogen Environments.

High-Temperature Oxidation of Zircaloy-4 in Steam and Steam-Hydrogen Environments.
NUREGCR4476

Publication Date	1986
Personal Author	Prater, J. T.; Courtright, E. L.
Page Count	31
Abstract	The oxidation kinetics of Zircaloy-4 in steam have been extended to 2400 C. The ZrO2 and alpha-Zr layers display parabolic growth behavior over the entire temperature range studied. A discontinuity in the oxidation kinetics at 1510 C causes rates to increase above those previously established by the Baker-Just relationship. This increase coincides with the tetragonal-to-cubic phase transformation in ZrO2-x. No additional discontinuity in the oxide growth rate was observed when the metal phase melted. The effects of temperature gradients were taken into account, and corrected values representative of near-isothermal conditions were computed. Oxide growth was also measured in various steam-hydrogen mixtures at 1565 C and 1815 C. Hydrogen concentrations up to 90 mol% had no effect on oxidation kinetics. The rate-controlling factor appears to be diffusion through the oxide layer.
Keywords	Oxidation Zircaloys Reaction kinetics Zirconium alloy zircaloy-4
Source Agency	Technical Information Center Oak Ridge Tennessee Nuclear Regulatory Commission
NTIS Subject Category	71N - Nonferrous Metals & Alloys 99F - Physical & Theoretical Chemistry 77H - Reactor Engineering & Nuclear Power Plants
Corporate Authors	Battelle Pacific Northwest Labs., Richland, WA.; Nuclear Regulatory Commission, Washington, DC. Office of Nuclear
Supplemental Notes	Sponsored by Nuclear Regulatory Commission, Washington, DC. Office of Nuclear Regulatory Research.
Document Type	Technical Report
Title Note	Technical rept.
NTIS Issue Number	198611