b'Project Description:TREAT performed transient research on multiple fuel systems concerning several reactor types including lightFigure 2. First SETH capsule water reactor (LWR) during its earlyinstalled in the irradiation vehicle suspended over a storage hole history (1960s era). Due to the laterat TREAT.arrival of LWR-focused transient test reactors (e.g., Power Burst Facility, now decommissioned) TREAT was incrementally upgraded and reconfigured with an increasing focus on engineering scale sodium loop tests in the era leading up to its operational suspension in 1994. Following system refurbishment and return to operation in late 2017, TREATs configuration represented a more capable facility, but historic data and experimental capabilities lacked relevance for modern ATF/LWR objectives. A series of first-of-a-kind transient shapes were performed on a nuclear mockup experiment to demonstrateenhancements including advanced TREATs capability and develop modelin-situ instrumentation. This approach, calibration data for LWR categorytermed the Minimal Activation transients including reactivity-initiatedRetrievable Capsule Holder (MARCH) accident and loss of coolant accidentirradiation vehicle system, makes use with great success. of a modular mechanical arrangement, An innovative approach to experimentstructural materials which minimize design was also developed so thatradioactive products, and strategic TREAT, and its supporting facilities,categorization of reusable safety could return to its roots withfunction components all to create higher throughput capsule-baseda cost/schedule effective method experiments while leveraging modernfor experiment design, irradiation, and logistics. A MARCH module 2019|AFC ACCOMPLISHMENTS 115'