b'limitations of the relatively simplisticration. For the metallic fuel experiment, THOR approach to passively producepins allocated for the planned but never thermal boundary conditions. Theexecuted M8 test have been located analysis clearly demonstrates itswith additional sister pins that will be complementary function with theused in the M-TOP/M-LOF experi-sodium loop currently under jointments. These pins were irradiated to development by INL and Terrapower.nearly 13 at% burnup in EBR-II. Sister A wide range of relevant time vs.pins were also tested in overpower temperature conditions are possibletests in EBR-II as well as in the historic using the THOR device encompassingWhole Pin Furnace for LOF simula-the conditions of interest for MOXtion. The as-built documentation and and metallic fuels. Some designirradiation histories for all pins have challenges that have been overcomebeen recovered and fuel performance include incorporation of full-length,models using BISON and JAEA code are intact EBR-II pins, incorporating anow nearing completion. Preparations range of advanced instrumentationare underway to transfer both sets of to ensure data objectives are met, andpins to Hot Fuel Examination Facility assembly considerations required for(HFEF) for pre-transient characteriza-remote glove box and hot-cell facili- tion and eventual experiment assembly.ties. As part of this process, a freshWhile comprised of important goals fuel commissioning experiment seriesand many challenges, the project has has been developed to measure/ made significant progress in its first calibrate specimen power in TREATyear to complete the final design of and demonstrate and qualify thea heat sink capsule to support broad system performance for use with highSodium Fast Reactor (SFR) studies value irradiated specimens. A detailedand beyond, but also identifica-conceptual design report was providedtion, recovery, and models of legacy to JAEA as a deliverable in Marchadvanced test specimens. The first 2020; the preliminary design for themodern experiments on advanced THOR device was held in June 2020;sodium reactor fuels will be performed the final design review for the devicein FY21. The THOR device has already is set to begin in September 2020. been identified by multiple other In parallel to device design andprograms a key capability to meet modeling activities, the experimenttheir needs. The transient and charac-design effort has focused on develop- terization data will support develop-ment of specimen configuration details.ment of advanced modeling capa-Working with the legacy database andbilities (working with Nuclear Energy JAEA, irradiated metallic and MOXAdvanced Modeling and Simulation fuel specimens have been located in an(NEAMS) for BISON code in U.S.) INL fuel storage facility to support theand aid U.S. and Japanese advanced testing objectives. The pins for the MOXreactor industries to provide safe and tests have been identified from EBR-IIeconomic nuclear energy.experiment X462A (or also called SPA-2B). The pins were irradiated to nearly 130 GWd/t in PNC1520 clad-ding with as-built annular fuel configu-2020|AFC ACCOMPLISHMENTS 133'