b'The chemical compatibility of uranium nitride with aluminum-forming austenitic alloys and liquid lead makes this proposed fuel-cladding-coolant combination a viable candidate for Generation IV lead-cooled fast reactors.The immerse experiments of UN in liquid metal also indicate a good compatibility between UNFigure 3. SEM of a top surface of and liquid lead. The characteriza- UN+UO 2with static Pb for 550C-500 tion of the interaction behavior ishr. Spherical precipitations of lead and lead oxide can be observedongoing. Our initial results show the precipitations of Pb and PbO (1.5 micron) observed on the surface of the UN pellets for the sample tested at 550C; however only limited penetration of liquid Pb into the UN matrix occurred through interconnected pores. The most extreme test (750C-1000 hrs) has yet to be characterized. In general, UN display a good compatibility with AFA and liquid Pb when tested at 550 and 750C with limited chemical interaction and liquid Pb penetration, and the fuel-cladding-coolant system could be viable for LFR applications.2023|AFC ACCOMPLISHMENTS 151'