Crystal Structure Evolution of U-Si Nuclear Fuel Phases as a Function of Temperature
- Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
The crystal structure of the U3Si2 line compound in the U-Si system was investigated as a function of temperature from room temperature t o1373 K using high temperature neutron time-of-flight diffraction on the HIPPO diffractometer at LANSCE. The U-Si system is actively researched due to its promise as an accident tolerant nuclear fuel. The simultaneous Rietveld refinement of five histograms from the five HIPPO detector rings provided fundamental datasets for the lattice parameters, anisotropic atomic displacement parameters, and atomic positions as a function of temperature. To explore the possibility of minority phases as a result of the synthesis route and especially due to hyper-stoichiometry, a stoichiometric U3Si2.00 sample and a hyper-stoichiometric U3Si2.01 sample were studied. While minor differences in the anisotropic atomic displacement parameters between the two samples were observed, over the entire investigated temperature range no additional phases were observed. However, significant differences in the thermal expansion behavior were identified between the two compositions that warrant future investigations.
- Research Organization:
- Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
- Sponsoring Organization:
- USDOE Office of Nuclear Energy (NE)
- DOE Contract Number:
- AC52-06NA25396
- OSTI ID:
- 1469500
- Report Number(s):
- LA-UR-18-28584; TRN: US1902840
- Country of Publication:
- United States
- Language:
- English
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