Assessment of oxygen diffusion during UO2--Zircaloy interaction

Off-normal light water reactor fuel element behavior is being studied as part of the Thermal Fuels Behavior Program (TFBP) conducted by EG and G Idaho, Inc., for the Nuclear Regulatory Commission. As part of this program, a series of single- and multiple-rod pressurized water reactor fuel behavior experiments have been performed in the Power Burst Facility (PBF) under various power-cooling-mismatch (PCM) conditions. Although the primary purpose of such integral experiments is to obtain fuel rod thermal and mechanical performance data, several chemical and metallurgical phenomena have been observed as a consequence of testing fuel rods under film boiling conditions. Such phenomena include zircaloy oxidation as a result of both steam-cladding and UO2-cladding interaction. Although analytical modeling of the steam-zircaloy interaction process has been developed over the past 15 years, the fuel-cladding interaction process has yet to be satisfactorily modeled