b'Advanced Fuels Campaign High Flux Isotope Reactor Irradiation Testing HighlightsPrincipal Investigator: Annabelle Le CoqTeam Members/ Collaborators: Christian Petrie, Kory Linton, Jason Harp, Jacob Gorton, Zane Wallen,Patrick Champlin, David Bryant, and Padhraic MulliganIrradiation testingM aterials and fuels irra- geometries such as kernels ( 425 diation testing at Oak Ridgeto 800 m), tri-structural isotropic in ORNLs High FluxNational Laboratory (ORNL)(TRISO) particles, or disk speci-Isotope Reactor (HFIR)leverages the High Flux Isotopemens, and various fuel forms (for supports advancementsReactor (HFIR) capabilities to studyexample, UN, UC, UO 2 , U 3 Si 2 , UCO).in the developmentvarious Accident-Tolerant Fuel (ATF)Post-irradiation examination (PIE) of various accident- material concepts. HFIR irradiationof the first MiniFuel target accom-tolerant fuel (ATF)experiment capsules (also referred tomodating UN kernels and TRISO material concepts. as rabbits) and full-length targetparticles was completed and includes designs allow small-scale specimensirradiation temperature analysis, to be irradiated at a particular damagefission gas release measurements, dose and temperature. Experimentsand fuel integrity analysis [2]. This can be inserted in HFIRs flux trap,first target achieved the designed removable beryllium (RB) reflector,target temperature ranging from or permanent beryllium reflectors450C to 550C and accumulated vertical experiment facilities (VXFs),a burnup of 10 MWd/kg U. Two depending on the irradiation goalsother Advanced Fuels Campaign and specimen geometry. Irradiation(AFC) targets containing UN and testing at ORNL is a major part inUCO compacts, and TRISO particles the development and qualificationhave completed irradiation and are of novel material and fuel conceptsintended for similar fuel performance to improve the accident-tolerance ofevaluation. To enhance the MiniFuel existing and future reactor designs.capability, the existing VXF position Current HFIR irradiation testing ofexperiment design was modified ATF concepts include MiniFuel targets,for RB positions, which are more cladding tube rabbits and targets, andreadily available and closer to the creep tube rabbit experiments. reactor core. The RB MiniFuel design Project Description is illustrated in Figure 1 [3]. Experi-ments inserted in such positions can MiniFuel experiments achieve heat generation rates and MiniFuel experiments, designed atburnup accumulation rates more than ORNL allow separate effects acceler- twice the VXF positions, enabling ated irradiation testing of miniaturehigher irradiation temperatures and fuel specimens [1]. The experimentreduced irradiation time to reach design accommodates various fuelsimilar burnups. In addition, the RB 154 2021|AFC ACCOMPLISHMENTS'