CAMPUS-ANNULAR: Preliminary multiphysics modeling of annular fuel performance under normal operating and accident conditions

Abstract

The internal and external cooled annular fuel was proposed firstly by MIT, which is found to be able to improve fuel performance dramatically. Based on the CAMPUS code, an annular fuel performance code called CAMPUS-ANNULAR is further developed in this work. And the multiphysics models of annular UO2 fuel equipped with Zircaloy cladding are developed under reactor normal operating, Loss Of Coolant Accident (LOCA) and Reactivity Initiated Accident (RIA) conditions, respectively. Then the BISON cladding failure criterion utilized under LOCA condition is introduced, and a loss of coolant and reflood model is implemented under LOCA condition for the first time. Additionally, the radial power distribution of annular fuel is introduced and analyzed in this work. Finally, the models implemented in this work are verified and the annular fuel performance under normal operating, LOCA and RIA conditions are investigated and compared with those of solid fuel. The fuel maximum temperature is found to be reduced dramatically by using annular fuel under normal operating, LOCA and RIA conditions, which may further lead to the cladding failure time to be delayed significantly under LOCA condition. Besides, the risk of fuel melting is found to be reduced by using annular fuel under RIA condition.