Non-destructive Quantitative Phase Analysis and Microstructural Characterization of Zirconium Coated U-10Mo Fuel Foils via Neutron Diffraction

Technical Report · Tue Oct 18 00:00:00 EDT 2016

DOI:https://doi.org/10.2172/1329816· OSTI ID:1329816

Cummins, Dustin Ray ^[1]; Vogel, Sven C. ^[1]; Hollis, Kendall Jon ^[1]; Brown, Donald William ^[1]; Dombrowski, David E. ^[1]

---

1. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

This report uses neutron diffraction to investigate the crystal phase composition of uranium-molybdenum alloy foils (U-10Mo) for the CONVERT MP-1 Reactor Conversion Project, and determines the effect on alpha-uranium contamination following the deposition of a Zr metal diffusion layer by various methods: plasma spray deposition of Zr powders at LANL and hot co-rolling with Zr foils at BWXT. In summary, there is minimal decomposition of the gamma phase U-10Mo foil to alpha phase contamination following both plasma spraying and hot co-rolling. The average unit cell volume, i.e. lattice spacing, of the Zr layer can be mathematically extracted from the diffraction data; co-rolled Zr matches well with literature values of bulk Zr, while plasma sprayed Zr shows a slight increase in the lattice spacing, indicative of interstitial oxygen in the lattice. Neutron diffraction is a beneficial alternative to conventional methods of phase composition, i.e. x ray diffraction (XRD) and destructive metallography. XRD has minimal penetration depth in high atomic number materials, particularly uranium, and can only probe the first few microns of the fuel plate; neutrons pass completely through the foil, allowing for bulk analysis of the foil composition and no issues with addition of cladding layers, as in the final, aluminum-clad reactor fuel plates. Destructive metallography requires skilled technicians, cutting of the foil into small sections, hazardous etching conditions, long polishing and microscopy times, etc.; the neutron diffraction system has an automated sample loader and can fit larger foils, so there is minimal analysis preparation; the total spectrum acquisition time is ~ 1 hour per sample. The neutron diffraction results are limited by spectra refinement/calculation times and the availability of the neutron beam source. In the case of LANSCE at Los Alamos, the beam operates ~50% of the year. Following the lessons learned from these preliminary results, optimizations to the process and analysis can be made, and neutron diffraction can become a viable and efficient technique for gamma/alpha phase composition determination for nuclear fuels.

• Research Organization: Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
• Sponsoring Organization: USDOE National Nuclear Security Administration (NNSA)
• DOE Contract Number: AC52-06NA25396
• OSTI ID: 1329816
• Report Number(s): LA-UR-16-27646; TRN: US1700409
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS
PHASE DIAGRAMS
NEUTRON DIFFRACTION
URANIUM BASE ALLOYS
BINARY ALLOY SYSTEMS
NUCLEAR FUELS
ZIRCONIUM
FOILS
FUEL PLATES
ROLLING
HOT WORKING
MOLYBDENUM ALLOYS
OXYGEN
PLASMA
PHASE STUDIES
TRACE AMOUNTS
DECOMPOSITION
MICROSTRUCTURE
SPRAYS
CONVERSION
POWDERS
URANIUM-ALPHA
URANIUM-GAMMA
LATTICE PARAMETERS
INTERSTITIALS