b'Development of the Temperature Heat sink Overpower Response Capsule for Use at Transient Reactor Test Facility Principal Investigators: D. Devin ImholteTeam Members/ Collaborators: Colby Jensen, Nicolas Woolstenhulme, Austin Fleming, Todd Birch, Randall Fielding, Scott Wilde, Cole Blakely, and Robert Armstrongto have an advanced instrumenta-The THOR device is an important new test platform fortion portfolio that is customizable TREAT supporting many customers already, allowing forfor measuring different phenomena passive heat rejection from test specimens to simulateof interest. At the same time, the important advanced reactor fuel conditions. THOR capsule has been standard-ized across these experiments to take advantage of similar hardware, T he Temperature Heat sinkwhile maintaining robust design Overpower Response (THOR)to withstand hot cell assembly and capsule is a Transient Reactor Testtransient events. The heat sink has (TREAT) Facility irradiation experi- been specifically designed to include ment vehicle for simulating transientan integral 1000 W cable heater for overpower events typical of Sodiumachieving high SFR operating and Fast Reactor (SFR) fuels. The heataccident temperatures of interest, sink within THOR, combined withalong with thermocouples and TREATs shaped transients, allows fordistributed temperature sensing unique transient temperature controlfibers for measuring fuel and clad-and energy densities characteristic ofding temperature response thru the overpower events. In addition, THORsheat sink. Figure 1 shows images of advanced instrumentation portfolioa fully instrumented heat sink, along enables flexibility for measuring fuelwith photographs of the recently temperature and timing of fuel failure.assembled THOR-C-1 heat sink. With The THOR capsule has been modi- the capsule being a welded Inconel-fied to support a variety or fresh and625 pipe enclosure, it is designed for pre-irradiated fuel specimen typesthe highest temperature conditions including U-10Zr, U-19Pu-10Zr, UO 2 ,of interest in SFR accidents.Mixed Oxide (MOX) and others. The THOR capsule also has a Project Description:configuration that is optimal for hot Given the broad range of fuelcell assembly. Whereas the fresh-fuel specimen types and test objectives,capsules have a straight hanger rod the THOR capsule has been designedand requires electrical connections to be made between the capsule and 148 2021|AFC ACCOMPLISHMENTS'