b'and local strain measurements to be used in the transient LOCA testing. Qualify this fabricated heated test rod for use in transient testing.AccomplishmentThe UW team (A.B. Luna, T. Moriera, M. Anderson) in collaboration with the OSU team (T. Howard, W. Marcum) designed two electrically heated rods to be used in the LOCA experiments in the OSU LOCA facility. These heater rods were fabricated by Stern Labs based on our design specifications. Delays in fabrication were encountered due to supply chain issues during the COVID pandemic. The heater rods have identical geometry, six internal thermocouples along the rod length,Objective 3: Design and modify theFigure 1. Dimensions are in mm unless along with three stainless steelcurrent OSU transient LOCA testnoted otherwise. (a) Schematic of capillary tubes for insertion of FOSfacility to allow for transient LOCAa 10.25 mm diameter and 254 mm within the rod and identical powerlong simulated nuclear fuel pin with testing. The modified facility will6 helical V-grooves machined on and heat flux profiles. The key differ- be qualified by performing scopingthe surface of the fuel cladding, 120 ence is one of the heater rods willLOCA tests and then installing thedegrees apart, 0.30 mm deep. (a have helical grooving on the exteriorinstrumented heated test rod into& c) Strain and temperature fiber heater cladding wall to accommo- optical sensors were embedded the OSU facility. side-by-side in the helical V-grooves date for incorporation of FOS pairsand will be used to monitor surface along the surface. The temperatureAccomplishment temperature, cladding elongation, and FOS is bare and sheathed in a steelThe OSU team (M. Moussaoui, T.bending. The temperature fiber data capillary attached to the rod to allowHoward, W. Marcum) has madewill be used as reference to decouple the strain and temperature data of strain-free measurement of themajor improvements in the designthe strain fiber. (b) Cross-Sectional distributed surface temperature. Theand operation of the OSU LOCA testview showing 6 locations for type-K FOS for strain measurement incorpo- facility. The facility supports testingthermocouples and 3 stainless-rates a FOS fixed in the groove of theof the heater rod with in-situ diag- steel capillaries for temperature fibers inside the cladding wallrod surface. By cross-comparison ofnostics using FOS for distributed these sensors, the mechanical straintemperature and strain measure-can be measured. This technique wasments. Improvements include [1] proven in UW steady-state tests for aa redesigned and fabricated heat heated rod under various pressures,exchanger for heat removal from temperatures and temperature gradi- the heater rod test rig, which allows ents. These instrumented heater rodsfor greater heat transfer and larger are to be shipped to OSU this quarter. natural circulation flow in the 2023|AFC ACCOMPLISHMENTS 183'