Texture Analyses and Microstructural Evolution in Irradiated Monolithic U-Mo Nuclear Fuel

Abstract

Great effort worldwide has been invested in replacing highly enriched uranium (HEU) fuel with lowenriched uranium (LEU) fuel in nuclear plants, in the frame of safeguarding nuclear material and promoting the proliferation resistance [1]. A monolithic U-Mo fuel type is being developed at Idaho National Laboratory for this purpose. This study focuses on the characterization of fresh and irradiated monolithic U-Mo fuel specimens to understand the effect of irradiation on the initial texture. Understanding, controlling and monitoring texture evolution under irradiation is important to evaluate material properties, as texture can affect up them up to 20-50% (e.g. Young's modulus, Poisson's ratio, strength ductility, toughness, thermal expansion, and magnetic-electrical properties) [2].

The formation of high burnup structure in U-Mo fuels

“…Authors postulate that at >3×10 21 fissions/cm 3 , continuous dynamic recrystallization (CDRX) is a potential contributor to the transition in LAGBs to HAGBs frequency at higher fission densities. The influence of fission density on the transformation of LAGBs to HAGBs is corroborated in Ref [7]. Furthermore, the mean local porosity calculated for each specimen was strongly correlated to the formation of HAGBs suggesting that the stress introduced in the microstructure by the gas pores may contribute to the microstructural transition to HAGB misorientation.…”