TRISO燃料颗粒三维多物理场耦合计算模型开发

Development of a 3D Multiphysics Coupled Computation Model for TRISO Fuel Particle

三向同性燃料(TRISO)颗粒是高温气冷堆弥散型燃料和全陶瓷微密封(FCM)耐事故燃料芯块的裂变区。为研究TRISO燃料颗粒在辐照环境中的复杂行为,基于COMSOL有限元软件开发了TRISO燃料颗粒的三维多物理场耦合性能分析模型。通过采用随辐照条件变化的材料物性参数和行为模型,可模拟燃料颗粒在稳态运行和事故工况下复杂的堆内热-力学行为,以及CO气体产生和裂变气体释放、裂变产物扩散等重要物理过程,还可以计算燃料颗粒的失效概率。基于COMSOL开发三维分析模型的计算结果与美国BISON程序对TRISO燃料颗粒的计算结果相比同样符合较好,说明了所开发模型的合理性。

TRISO fuel particle is the area where fission reaction occurs for high-temperature gas-cooled reactor fuel and FCM accident-tolerant fuel pellet. To investigate the complicated behaviors of TRISO fuel particle under irradiation, a 3D multiphysics-coupled computation model for fuel performance analysis was developed based on the COMSOL finite element software. Using the irradiation-dependent material properties and behavior models, this model is capable of simulating the complicated in-pile thermo-mechanical behavior under steady-state and accident conditions, important phenomena such as fission gas release, production of CO gas and diffusion of fission products, as well as failure probability of fuel particle. The IAEA CRP-6 benchmarks were employed to validate the model, which showed good agreement of the results between COMSOL and other codes; the simulation of TRISO fuel particle conducted by using BISON was also consistent with the results obtained by the COMSOL model, which indicated the reasonability of the model in the present study.