Simulation on the Multidimensional Behavior of TRISO Particle Fuel With UN/ UO2 Kernel

As one of the new advanced fuels proposed to improve the safety of nuclear reactors, fully ceramic microencapsulated (FCM) fuel consisting of TRistructural ISOtropic (TRISO) particles dispersed in a silicon carbide matrix has received a lot of attention at home and abroad because of its distinguished advantages such as high corrosion resistance and excellent fuel irradiation stability. For analyzing FCM fuel performance and optimizing FCM fuel design, it is necessary to assess complicated behaviors of TRISO particle fuel under irradiation. To investigate the multidimensional behavior of TRISO particle fuel with UN or UO2 kernel, a three-dimensional thermomechanical coupling model was developed based on multiphysics coupling finite element software COMSOL. Additionally, thermomechanical performance analysis of TRISO particle fuel with irradiation-dependent material properties and behavior models was conducted, and important phenomena were implemented such as fission gas release, production and diffusion of CO gas, as well as the evolution of particle radius due to the irradiation deformation, fission product swelling strain and irradiation creep. Moreover, on the basis of the preliminary thermomechanical analysis, the performance of TRISO particle fuel with UO2 and UN kernel were compared. This paper is intended as an exploratory investigation of TRISO fuel behavior, which will provide vital reference for further performance analysis and design optimization of subsequent FCM fuel.