b'Super-SERTTA, however, did offerrators at Oregon State University the ability to test longer rods in a(OSU) created mock-ups of the capsule device. TWERL was found toLOCA-SERTTA capacitive discharge represent the desired conditions veryburst disc rupturing system and well and offered the notable abilitydemonstrated it viability as a compact to house longer rods in multi-rodremote operable valve to induce bundles to help simulate refinedthe blowdown. The team held both post blowdown boundary conditionsconceptual and preliminary design affected by neighboring rods suchreviews in accordance with INL as azimuthal temperature variationsengineering procedures. The device and balloon-to-balloon interac- was designed with an instrumenta-tions. The ultimate recommendationtion package consistent with, and reached by these studies was toin some regards advanced beyond, focus on detailed design and deploy- the approach used at the HBWR. ment of LOCA-SERTTA to addressThe capability to represent fully near term FFRD data needs for base- prototypic thermal evolution in the line UO2 fuel in zirconium alloyfuel will be unique in the world cladding. The TWERL concept wasand beyond the in-pile capability also recommended for continuedonce available at HBWR, as a crucial pursuit for its ability to address allcapability to address FFRD related relevant phenomena for advancedquestions for high burnup fuels in accident tolerant fuel (ATF) designsthe near term and to support detailed so that it is ready when high burnupcharacterization of ATF fuels as well. ATF specimens become available. Future work in 2021 will complete Having reached this conclusion, thethe final design phase and construct a team proceeded to perform detailedfull assembly prototype for lab testing design work and started mockupin preparation for commissioning testing of LOCA-SERTTA features.irradiations with fresh fuel later in Experiment safety analyses werethe year.largely performed to permit its irradiation at TREAT. Finally, collabo-2020|AFC ACCOMPLISHMENTS 111'