b'Figure 4. (Left) Post-transient radiography of THOR-C-2 showing clear regions of disrupted fuel. (Middle) Hodoscope view of THOR-C-2 test specimen. (Right) Corresponding waterfall plot of each column during the experiment, again showing the point of failure and the behavior of the fuel during the eventinternal pin pressure. The data fromthe success of diagnostics to detectof the annulus during the transient.the experiment shows excellentand characterize fuel failure behaviors. Completion of design and quali-performance of the primary in-situTHOR-C-3: First experiment onfication of THOR capsule remote measurements and experimentannular, Na-free metallic fuel typehandling capability for HFEF. This design goals. Fuel pin failure waswith an infrared pyrometer in the capability builds on the established detected via the capsule pressurefuel center hole. THOR-C-3 is currentlycapability to handle the first TREAT sensor, corroborated by significantassembled ready for irradiation to beexperiment device in HFEF, the fuel motion measured online by thecompleted by the end of SeptemberStatic Environment Rodlet Transient TREAT hodoscope system and seen2022. THOR-C-3 will undergo twoTest Apparatus (SERTTA) capsule, in post-test radiography at TREAT,distinct experiments, i.e., transients,in 2020. The integration of most and by delayed temperature signalstaking advantage of the in-fuelTREAT designs into HFEF environ-in the heat sink thermocouples.temperature measurement. Thement is a fundamental need for Based on pretest model predictions,direct fuel temperature measurementtransient testing nuclear fuels. The the fuel surpassed the liquidus pointwill provide further measurement ofengineering team has done a stellar for the U-10Zr fuel of 1371C and thereactor-specimen energy coupling,job in meeting project demands and fuel-cladding interface surpassed theusing a optical fiber for the first timehas made significant improvements low U-concentration Fe-U eutecticin fuel in-pile. The first transientin the overall experiment integration threshold of approximately 1078C.will be a sinusoidal power profilestrategy in HFEF. The increased X-ray radiography is planned atto evaluate the ability of the THORmomentum is encouraging for next the TREAT facility. Later, neutroncapsule to characterize integralsteps for other TREAT devices such computed tomography will befuel thermal transport. The secondas the Transient Water Irradiation performed on the capsule using thetransient will push the annular fuelSystem in TREAT (TWIST) capsule Neutron Radiography (NRAD) facility.in a severe overpower condition as aand the Mk-IIIR Na loop.Each test will be analyzed baseddirect comparison with THOR-C-4 on on as-run data using detailed fuela traditional fuel form. This will be performance models. Figure 3 andthe first transient overpower test on Figure 4 summarize data resultsannular fuel to observe fuel-cladding collected from THOR-C-2 highlightingmechanical interaction and behavior 2022|AFC ACCOMPLISHMENTS 133'