NSUF 18-1192: Synchrotron X-ray Characterization of the Microstructural Evolution of U Alloys Irradiated to Low Fluences

Metallic fuels are relevant to many reactor types, including advanced reactors, as well as research and test reactors. Historically, much of the fuel performance testing focused on high burn-up irradiations. This has left the community with a large knowledge gap of fuel behavior that is not well known at low burn-ups (fluences). The proposed work will address some of the data gaps for low fluence irradiated metallic fuels through specifically understanding how their microstructure has evolved. This changing microstructure can provide insight into constituent redistribution and swelling. Ultimately, these findings will lead to more robust fuel performance codes that incorporate low fluence data that was previously lacking. The microstructure of low fluence (0.01 and 0.1 dpa) irradiated fuels, including U-x wt.%Zr, where x = 0, 10, 15, and 20 and U-y wt%Mo, where y = 7 and 10, will be assessed using synchrotron X-ray diffraction (XRD) and pair distribution function (PDF) at the X-ray Powder Diffraction (XPD) beamline at NSLS II (anticipated in Winter/Spring 2018). The use of these combined techniques will provide information regarding the phase types, phase fractions, nanoscale crystallite sizes, lattice parameters, and short/long-range ordering following two decades of irradiation, as well as a comparison to controls. The specimens were irradiated at temperatures ranging from 150oC to 800oC, of which there are a total of 86 specimens. Note that the samples are currently mounted in the approved NSLS II top hats for XPD. A total of 2 days are requested for XPD beamtime, where 1 day is utilized for set-up and the remainder are used for measurements.

Additional Info

Field	Value
Abstract	Metallic fuels are relevant to many reactor types, including advanced reactors, as well as research and test reactors. Historically, much of the fuel performance testing focused on high burn-up irradiations. This has left the community with a large knowledge gap of fuel behavior that is not well known at low burn-ups (fluences). The proposed work will address some of the data gaps for low fluence irradiated metallic fuels through specifically understanding how their microstructure has evolved. This changing microstructure can provide insight into constituent redistribution and swelling. Ultimately, these findings will lead to more robust fuel performance codes that incorporate low fluence data that was previously lacking. The microstructure of low fluence (0.01 and 0.1 dpa) irradiated fuels, including U-x wt.%Zr, where x = 0, 10, 15, and 20 and U-y wt%Mo, where y = 7 and 10, will be assessed using synchrotron X-ray diffraction (XRD) and pair distribution function (PDF) at the X-ray Powder Diffraction (XPD) beamline at NSLS II (anticipated in Winter/Spring 2018). The use of these combined techniques will provide information regarding the phase types, phase fractions, nanoscale crystallite sizes, lattice parameters, and short/long-range ordering following two decades of irradiation, as well as a comparison to controls. The specimens were irradiated at temperatures ranging from 150oC to 800oC, of which there are a total of 86 specimens. Note that the samples are currently mounted in the approved NSLS II top hats for XPD. A total of 2 days are requested for XPD beamtime, where 1 day is utilized for set-up and the remainder are used for measurements.
Award Announced Date	2018-02-01T14:14:06.493
Awarded Institution	None
Facility	None
Facility Tech Lead	Simerjeet Gill
Irradiation Facility	None
PI	Maria Okuniewski
PI Email	[email protected]
Project Type	RTE
RTE Number	1192