b'Figure 2. Fuel centerline and outer cladding temperature predictions for an HBu PWR LBLOCA and TWIST HBu LOCA experiment. Blowdown at time zeroFigure 3. Fuel radial temperature distribution during various times of the transient. Solid Lines: TWIST; Dashed Lines: PWRsubcritical, which leads to a signifi- the outer portion of the fuel and the cant reduction in heat generation incladding increase rapidly at approxi-the fuel. This rapid loss of coolingmately the same rate. This has been and heat generation causes the storedtermed stored energy heatup (SEH).energy within the fuel to redistributeTo date, LOCA experiments driven radially, resulting in a rapid tempera- by a large SEH have never been ture decrease of ~100C/s at the centerperformed on HBu fuel. Currently, of the fuel, while the temperature ofonly experiments which are consis-110 2023|AFC ACCOMPLISHMENTS'