b'The capsule-based approach to LOCA testing at TREAT will help close near-term data gaps for in-pile fuel fragmentation phenomena to support licensed burnup increases for LWR fuel technologies. in the recently restarted TransientRecirculating Loop (TWERL).All Reactor Test facility (TREAT).three concepts had a blowdown tank Thermal-hydraulic modeling wasconnected via remote-operable valve performed on three candidate testso that TREATs reactor power history vehicle designs to determine whichcould be synchronized with capsule represented the best approach fordepressurization to faithfully simulate resolving FFRD-related data gaps inthe postulated transition from steady support of near-term project goals.state operation to LOCA conditions. This summary gives a brief overviewUnlike furnace-based LOCA testing of these efforts and conclusions. where external heating is used Project Description:(which is a valid approach for LOCA Three irradiation vehicle approachestesting centered around cladding were conceptualized for TREAT-basedperformance) TREATs ability to drive LOCA testing. These devices wereinternal nuclear heating offered the compared to each other with thermalunique ability to simulate representa-hydraulic modeling in the RELAPtive radial power profiles and resulting code. The first was a small capsulethermomechanical stresses in the in the Static Environment Rodlettest fuel. Hence, design tuning and Transient Test Apparatus (SERTTA)modeling emphasis was placed on family of water capsules entitledsimulating the full evolution of both LOCA-SERTTA. The second was ancladding and fuel centerline tempera-enlarged capsule version referredtures throughout the LOCA evolution. to as Super-SERTTA.The third was an even larger pump-driven system termed the TREAT Water Environment 2020|AFC ACCOMPLISHMENTS 109'