Microstructural assessment of U-rich U-Zr alloys for advanced nuclear fuels

Abstract

Uranium-zirconium alloys are being investigated for use in metallic inert matrix nuclear fuels (IMF). The IMF platform provides opportunities to study the system components (fuel, metallic matrix, and cladding) separately prior to studying their interactions in the integrated fuel form. As-cast, U-rich U-Zr alloys (2, 5, 10 wt% Zr) were characterized using X-ray diffraction, optical microscopy, and both scanning and transmission electron microscopy. It will be shown that the alloys consist of the orthorhombic α-U and hexagonal δ-UZr2 phases and that detection of the δ phase, as well as accurate assessment of the morphology and compositions of the phases, requires the high spatial resolution of the transmission electron microscope. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344. Work at LLNL was funded by the Laboratory Directed Research and Development Program at LLNL under project tracking code 12-SI-008.