Microstructure of as atomized and annealed U-Mo7 particles: A SEM/EBSD study of grain growth

Research output: Contribution to journalArticle


  • Ann Leenaers
  • Xavière Iltis
  • Isabelle Zacharie-Aubrun
  • Ho Jin Ryu
  • Jongman M. Park
  • A.M. Yacout
  • Dennis D. Keiser
  • Florence Vanni
  • Bertrand Stepnik
  • Thierry Blay
  • N. Tarisien
  • C. Tanguy
  • Herve Palancher

Institutes & Expert groups

  • CEA Cadarache - Commissariat à l'Énergie Atomique
  • Argonne National Laboratory
  • INL - Idaho national Laboratory
  • FCEC - Framatome Construction engineering company
  • CEA Saclay - Commissariat à l'énergie atomique
  • Korean Advanced Institute of Sciene and Technology
  • ORANO (previous AREVA) - France

Documents & links


Significant progresses in the performances under in-pile irradiation of particular U-Mo based fuels have been observed over the last fifteen years. One of the remaining issues has still to be tackled for use as a LEU fuel in the high power research reactors: the U-Mo recrystallization and its associated swelling have to be controlled or delayed. One way to mitigate this problem would be to optimize the initial microstructure of U-Mo atomized particle, by homogenizing Mo concentration and increasing grain size. This paper mainly focuses on U-Mo grain growth. Based on samples prepared in the framework of KOMO-5 and EMPIrE tests, a methodological work based on the use of EBSD is presented. In particular, surface preparation procedures are proposed for powders and rods, this last one being most likely readily applicable for plate analysis. As-atomized microstructures are analyzed in detail and subsequently compared to those obtained on particles annealed at 1000 °C under various conditions. It is found that 1 h annealing under vacuum is a good compromise of temperature and time to meet the development goals, provided that few impurity precipitates are present within U-Mo particles, since these can impact grain growth.


Original languageEnglish
Article number495
Pages (from-to)249-266
Number of pages18
JournalJournal of Nuclear Materials
Publication statusPublished - 1 Nov 2017


  • U-Mo, Grain growth, Nuclear research reactor fuels, Powder metallurgy, EBSD

ID: 5655759