b'This work represents the first look at PIE and as-run analysis of the first AFC FAST tests and the effects from scaled irradiation fuels testingperformance between novel designsof physics-based models by virtue of against established performancethe departure from fully prototypic metrics. The solution of simplyirradiation and thus an improved, accelerating irradiation, however,broader basis for validating perfor-requires consideration of manymance codes against.other phenomena that FAST can provide answers for. PhenomenaAccomplishments:such as fission product diffusionThe power histories of the FAST and alloy re-distribution arefueled specimens during irradiationheavily influenced by temperaturewere calculated and used for thermal gradients, time at temperature,analysis of the FAST pins. Thermal and concentration gradients. Byanalysis profiles and contours gener-scaling the geometry to a reducedated from the as-run power histories are presented in Figure 1 for FAST-007.Figure 2. (above) A comparison size and reducing the total timeThese contour plots are useful inbetween EBR-II experiment DP10 (right) under irradiation, the balance ofunderstanding potential effectsand threediameter FAST capsules time and distance for diffusionstacked alongside it (right). The FAST centric phenomena is tested. Thisfrom the size of the rodlets andmethod is shown to adequately results from PIE, especially duringrepresent the bottom, middle, and top has important implications forfuture destructive examinationportions of the DP10 experimentdeveloping high burnup alloy fuelwhere chemical and microstructural as the roles of alloy redistributionanalyses can be performed. Axial and fission product concentrationsand radial gradients are compared at the cladding are both importantwithin the rodlet as to help under-fuel performance metrics. This addsstand the impacts of reduced scale additional value to the use of FASTtesting. Axial thermal gradients as it provides critical data to theexisted to some degree in the previous development and implementationAFC and EBR-II tests, but the fraction 2022|AFC ACCOMPLISHMENTS 127'