多层结构包壳和非刚体芯块力学建模及应用

Multi-layer Clad and Non-rigid Pellet Mechanical Modeling and Its Application

针对事故容错燃料(ATF),基于有限差分法开发了多层圆柱体力学模型。将新模型植入FRAPCON4.0程序中,并替换了原有Fracas模型。通过对相同对象计算,对比了新旧模型的特点并验证了新模型的合理性和先进性。对比发现,大部分参数结果吻合良好,佐证了非刚体芯块假设对于传统燃料具有一定合理性,但旧模型对接触压力的预测过于保守,改进后程序的预测结果更合理。最后,分析总结了所开发新型多层结构包壳模型和改进后FRAPCON 4.0在燃料性能分析中潜在的应用。

Based on the finite difference method,the mechanical model of multi-layer cylindrical body was established for accident tolerant fuel（ATF）.The new model was implemented in FRAPCON 4.0 code to replace the original Fracas model.By the simulation for the same research objective,the characteristics of the new and old models were analyzed and the rationality and advancement of modification were validated.The comparison indicates that most of parameters agree well,demonstrating that the non-rigid fuel assumption is reasonable to some extent for the traditional fuel.However,the old model is over conservative in contact pressure prediction,and the upgraded code provides more reasonable result.Finally,the potential application of the multi-layer mechanical model and the upgraded FRAPCON 4.0 in the fuel behavior analysis was predicted.