| Abstract Scope |
Fission products play a crucial role in the fuel-cladding chemical interaction (FCCI) phenomenon, affecting the mechanical integrity of fuel-cladding systems. Insights from studying fission products and FCCI can guide the development of advanced metallic fuels with improved performance. We investigated the FCCI region of a pseudo-binary metallic U-10M (10M=5Mo-4.3Ti-0.7Zr wt.%) fuel, irradiated at the Advanced Test Reactor (ATR) to a burnup rate of 2.2 at%, using high-resolution characterization techniques such as transmission electron microscopy (TEM), atom probe tomography (APT) and electron energy loss spectroscopy (EELS). TEM results revealed the presence of lanthanide fission products (Ln FPs), Ti, and Mo in the FCCI region. The dominant phases in the FCCI region were cubic (U,Zr)(Fe,Cr)2 and tetragonal σ-FeCr. EELS analysis detected Ba, Cs and Ti near circular pores. Atom probe tomography (APT) characterization of tips from the fuel side of the FCCI region revealed a variety of fission product (FP) elements, including Kr, Gd, and Dy. The compositional changes observed in the APT analysis indicated the presence of a Zr-rich rind between the Fe-rich and FP-rich regions. APT tips from the HT9 cladding showed no signs of clustering or precipitation of any element. This work highlights the alloying effects of Ti and Mo in the FCCI region and explains the impact of irradiation temperatures on metallic fuels, providing a benchmark for future studies on FCCI region of pseudo-binary metallic fuels. |