NSUF 22-4388: An Assessment of Radial Compositional Variations of the Grey Phase in FBR MOX Fuel Using EPMA

Throughout the literature, there are variations in the reported composition for the grey phase. There is a general understanding that the phase is an oxide phase with barium, zirconium, uranium, plutonium, and molybdenum. However, the expected compositional range for the phase has not been determined. Electron probe microanalysis (EPMA) can be used to fill in this knowledge gap by collecting radial line scans in the central and mid-radial regions on a sample of fast breeder reactor (FBR) mixed oxide (MOX) fuel. The sample of MOX fuel proposed for analysis in this work has a unique distribution of grey phase throughout the central and mid-radial regions that is not commonly observed in these fuels. Conducting a radial EPMA analysis on this sample provides the opportunity to correlate the composition of the grey phase to temperature, which has not yet been done. The compositional information obtained from this work will greatly improve our understanding of the grey phase and its formation, which can be used to enhance thermodynamic models. With an expected timeline of two months, this project will not only improve our understanding of the grey phase in MOX fuels, but other oxide fuels, such as light water reactor UO2 and accident tolerant oxide fuels, that are also impacted by grey phase formation.

Additional Info

Field	Value
Abstract	Throughout the literature, there are variations in the reported composition for the grey phase. There is a general understanding that the phase is an oxide phase with barium, zirconium, uranium, plutonium, and molybdenum. However, the expected compositional range for the phase has not been determined. Electron probe microanalysis (EPMA) can be used to fill in this knowledge gap by collecting radial line scans in the central and mid-radial regions on a sample of fast breeder reactor (FBR) mixed oxide (MOX) fuel. The sample of MOX fuel proposed for analysis in this work has a unique distribution of grey phase throughout the central and mid-radial regions that is not commonly observed in these fuels. Conducting a radial EPMA analysis on this sample provides the opportunity to correlate the composition of the grey phase to temperature, which has not yet been done. The compositional information obtained from this work will greatly improve our understanding of the grey phase and its formation, which can be used to enhance thermodynamic models. With an expected timeline of two months, this project will not only improve our understanding of the grey phase in MOX fuels, but other oxide fuels, such as light water reactor UO2 and accident tolerant oxide fuels, that are also impacted by grey phase formation.
Award Announced Date	2022-06-14T07:30:28.88
Awarded Institution	None
Facility	None
Facility Tech Lead	Alina Zackrone
Irradiation Facility	None
PI	Casey McKinney
PI Email	[email protected]
Project Type	RTE
RTE Number	4388