b'Figure 2. Backscatter electron montagebonded fuel, thanks to an on-goingwas expected to release Zr and form image of half fuel cross-section ofoptimization of the design andstable intermetallic compounds with U-13Zr-4Pd annular fuel irradiatedfabrication [1]. lanthanides. This concept has been as part of AFC-3D experiment to a burnup of 2.7 %FIMA. In the image,As already mentioned before,tested earlier [4] discovering issues different microstructures are evidentpalladium has been proposed asattributed to Zr Pd intermetallics that and identified in 4 main regions (from 1removed Zr from the U matrix, and to 4). Most of the cladding is not visiblean additive to metallic fuel to helpleading to increase interaction in and detached from a closed contactprevent lanthanide-initiated FCCI in with the fuel during sample preparation. U Zr alloys at high burnup [2,3].between U and the cladding. To help During fabrication, Zr and Pd form amitigate this problem in a later AFC-3 stable intermetallic compound, and Pdtest (reported here) the fuel composi-tion was changed with addition of Figure 3. Backscatter electron images showing in detail the different regions from Figure 2. In the periphery of the fuel (region 1-2) Pd is found mainly associated with rare earth, while in the central regions (3-4) Pd-Zr precipitates are the majority. 136 2020|AFC ACCOMPLISHMENTS'