Phase analyses of silicide or nitride coated U-Mo and U-Mo-Ti particle dispersion fuel after out-of-pile annealing

Abstract

The coating of silicide or nitride layers on U-7 wt% Mo or U-7 wt% Mo-1 wt% Ti particles has been proposed for the minimization of the interaction phase growth in U-Mo/Al dispersion fuel during irradiation. Out-of-pile annealing tests show reduced inter-diffusion by forming silicide or nitride protective layers on U-Mo and U-Mo-Ti particles. To characterize the constituent phases of the coated layers on U-Mo and U-Mo-Ti particles and the interaction phases of coated U-Mo and U-Mo-Ti particle dispersed Al matrix fuel, synchrotron X-ray diffraction experiments have been performed. It was identified that silicide coating layers consisted mainly of U3Si5 and U4Mo(MoxSi1-x)Si-2, and nitride coating layers were composed of mainly UN and U4N7. The interaction phases obtained after annealing of coated U-Mo and U-Mo-Ti particle dispersion samples were identical to those found in U-Mo/Al-Si and U-Mo/Al systems. Nitride-coated particles showed less interaction formation than silicide-coated particles after annealing at 580 degrees C for 1 h owing to the higher susceptibility to breakage of the silicide coating layers during hot extrusion. (C) 2013 Elsevier B. V. All rights reserved.