b'Demonstration of a Transient Heating and Visualization Systemto Collect and Characterize Fission Gas Release on IrradiatedNuclear FuelPrincipal Investigator: Peter DoyleTeam Members/ Collaborators: Jason Harp, Ben Garrison, Kory LintonThe Fuel Heating and Visualization System demonstrates aT he kinetics of fission gas release under high temperature transients is an important key capability at ORNL to evaluate and observe fission gasconsideration for increasing burnup release in local sections of nuclear fuel. of nuclear fuel in Light Water Reac-tors (LWRs). Several groups have FullCollimator b Microscope Power Fan Voltage Control performed experiments to under-a System c Supply stand different portions of fission gas release [13] and others have Dichroic Camera conducted work to model fission gas Mirror Camera IrisMount release, with a particular focus on gas bubble physics [4,5]. Although Microscope CapacitancePressure many important details regarding Meter Power for Transducers mechanisms of gas release have MicroscopeIris d Back of Control Cabinet been determined by these efforts Control Limit Input Furnace [6], several outstanding questions Temperature PowerInput Switch remain to be addressed to aid in modeling fission gas behavior under high-burnup conditions. Addition-Microscope ally, transient fission gas release was Stage identified as a critical gap in data e Vacuum f Front of Control Cabinet available to support the extension Section of the burnup limit for commercial LED Power light water reactors [7]. A key aspect LED and Controller in addressing these questions is the Collimator Viewport Adapter Limit Capacitance development of experiments in Heated Section Switch Meter Controller which several types of information Process are gathered simultaneously.Power and Gas ControllerTransfer Flange Project Description:DESO Valve Isolation Valve Vacuum Switch The objective of this work was to develop a rapid transient Figure 1. Images of the system and control cabinet. Full testing station,testing technique allowing visual together with major tubing elements (a). Microscope section of the systemobservation of an irradiated fuel with important components labeled; capacitance meter shown as it protrudessample during a temperature above the top plate of the frame (b). Power supply used to power the pressure transducers and cooling fans (c). Control cabinet with various componentstransient while measuring the indicated (d and f). Components inside the cabinetincluding the serial hub,amount of fission gas released LabJack, stage motor controller, and spectrometerare not shown. Testand collecting fission gas for portion of the systems vacuum section, with important features labeled (e) post-test characterization. 96 2022|AFC ACCOMPLISHMENTS'