Transient fuel performance analysis of UO2-BeO fuel with composite SiC coated with Cr cladding based on multiphysics method

摘要: The transient multiphysics models were updated in CAMPUS to evaluate the accident-tolerant fuel performance under accident conditions. CAMPUS is a fuel-performance code developed based on COMSOL. The simulated results of the UO2-Zircaloy fuel performance under accident conditions were compared with those of the FRAPTRAN code and the experimental data to verify the correctness of the updated CAMPUS. Subsequently, multiphysics models of the UO2-BeO fuel and composite SiC coated with Cr (SiCf/SiC-Cr) cladding were implemented in CAMPUS. Finally, the fuel performance of the three types of fuel-cladding systems under Loss Of Coolant Accident (LOCA) and Reactivity Insertion Accident (RIA) condtions were evaluated and compared, including the temperature distribution, stress distribution, pressure evolution, and cladding failure time. The results showed that the fuel temperature of the UO2 fuel under accident conditions without pre-irradiation was lower after being combined with SiCf/SiC-Cr cladding. Moreover, the centerline and outer surface temperatures of the UO2-BeO fuel combined with SiCf/SiC-Cr cladding reduced further under accident conditions. The cladding temperature increased after the combination with the SiCf/SiC-Cr cladding under accident conditions with pre-irradiation. In addition, the use of SiCf/SiC-Cr cladding significantly reduced the cladding hoop strain and plenum pressure.