Identification and quantification of hydride phases in Zircaloy-4 cladding using synchrotron x-ray diffraction.
Zirconium hydrides precipitate in fuel cladding alloys as a result of hydrogen uptake from the high-temperature corrosion environment of light water reactors. Synchrotron X-ray diffraction was performed at room temperature on stress-relieved Zircaloy-4 cladding with two distributions of hydrides - (1) uniformly distributed hydrides across the entire cladding wall and (2) hydride rim next to the outer surface. The {delta}-hydride phase was found to be the predominant hydride phase to precipitate for hydrogen contents up to 1250 weight parts per million (wt ppm). At a higher content, about 3000 wt ppm, although {delta}-hydride is still the majority phase, a significant amount of {gamma}-hydride is also observed. At even higher hydrogen contents, in excess of approximately 6000 wt ppm, such as can occur in a highly dense hydride layer, peaks associated with the {epsilon}-hydride phase are also observed in the diffraction pattern. The volume fraction of hydrides was estimated as a function of hydrogen content using the integrated intensities of select diffraction peaks corresponding to the {alpha}-Zr matrix and the hydride phases. These estimated values agree well with calculated values from the independently measured concentrations. The results of this study indicate that hydride precipitation in Zircaloy-4 is a complex process of evolving hydride phases with increasing local hydrogen content.
- Research Organization:
- Argonne National Lab. (ANL), Argonne, IL (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC); USNRC
- DOE Contract Number:
- DE-AC02-06CH11357
- OSTI ID:
- 985625
- Report Number(s):
- ANL/NE/JA-62450; TRN: US1006170
- Journal Information:
- J. Nucl. Mater., Vol. 392, Issue 3 ; Aug. 1, 2009
- Country of Publication:
- United States
- Language:
- ENGLISH
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