b'3.1 FUEL FABRICATION AND PROPERTIESNuclear Energy University Project (NEUP) AwardChemical Interaction and Compatibility of Uranium Nitride Fuels with Liquid Pb and Alumina-forming Austenitic AlloysPrincipal Investigator: Jie Lian, Rensselaer Polytechnic University (RPI) Team Members/Collaborators: Bruce Pint, Jiheon Jun and Jason Harp, (Oak Ridge National Laboratory; ORNL), Erofili Kardoulaki, (Los Alamos National Laboratory; LANL), Michael R. Ickes (Westinghouse Electric Company)I n this project, the chemicalThis project targets the critical interaction behaviors ofissue of chemical interaction and uranium nitride (UN) andcompatibility among UN fuels, alumina forming austenitic alloysAFAs and liquid Pb. The technical (AFAs), and UN and liquid lead (Pb)objectives of this research project were investigated through the useinclude: (1) to testify the hypothesis of diffusion couple and liquid metalof good compatibility of UN with immersion experiments, respec- liquid metal Pb and AFAs; (2) to tively. Experiments were conductedidentify any possible interaction at 550 and 750C for 500 and 1000and compatibility issues of UN hours in inert environments. Bothfuels and optimized AFAs with the preoxidized AFA and as-cast AFApresence of liquid metals at elevated were tested. Monolithic uraniumtemperatures; (3) to understand how nitride and uranium mononitridedifferent fuel chemistry, impuri-with 3 wt% of secondary phasesties, phases, and coolant chemistry including metallic uranium,(specifically oxygen control) uranium dioxide, and uraniumimpact fuel-cladding interaction nitride (U 2 N 3 ) were used in orderand compatibility with liquid Pb to study the effects of secondarycoolant/sublayer; and (4) to achieve phases on the chemical interactiona comprehensive understanding of behavior among UN-AFA-Pb. the interaction and compatibility of this fuel-coolant-cladding system Project Description:and recommendation of operation UN is considered as a primary fueltemperature for practical applica-form for lead-cooled fast reactorstions. Chemical interaction and (LFRs) due to its enhanced fissilecompatibility of UN fuels with element density, higher thermalliquid Pb and AFAs are critical for conductivity, better breedingthe long-term performance evalua-ratios and neutronic economicstion of the fuel, coolant, and struc-as compared with oxide fuels;tural materials for LFRs. The critical however, knowledge gap existsobtained on fuel-coolant-cladding in the fuel-cladding interactionchemical interaction and compat-with the presence of liquid metal. 148 2023|AFC ACCOMPLISHMENTS'