UN核芯TRISO包覆燃料颗粒性能分析

Performance Analysis of TRISO Coated Fuel Particle with UN Kernel

为分析致密热解碳层、内压等因素对TRISO包覆燃料颗粒热-力学性能的影响,基于多物理场耦合软件COMSOL建立了以UN为核芯的TRISO包覆燃料颗粒三维热-力学耦合模型,并通过IAEA CRP-6基准题进行了验证。利用本文模型对稳态运行及反应性引入事故(RIA)工况下典型TRISO包覆燃料颗粒的性能进行了分析,结果表明,正常运行工况下SiC层能维持结构完整性,但IPyC层存在失效风险,需进一步优化TRISO包覆燃料颗粒的设计方案,而RIA工况下热膨胀是造成TRISO包覆燃料颗粒发生结构失效的主要原因。该模型能对轻水堆运行环境下的TRISO包覆燃料颗粒进行复杂的多物理场耦合性能分析,为进一步优化FCM燃料元件设计打下基础。

For the purpose of analyzing the impact of PyC layers,internal pressure etc.on the thermomechanical performance of TRISO coated fuel particle,a 3 Dthermomechanical coupling model was developed for TRISO coated fuel particle with UN as the kernel by using the multi-physics coupling software COMSOL,and the model was validated against the IAEA CRP-6 benchmark.Performance analysis of the TRISO coated fuel particle with typical design parameters was conducted under steady state and reactivity introduced accident(RIA)conditions.The results show that the SiC layer maintains its structure integrity,but the IPyC layer has the potential of failure in steady state condition.Further improvement to the design of TRISO coated fuel particle is required.For the RIA condition,thermal expansion is a dominant factor resulting in the loss of structure integrity of the TRISO coated fuel particle.The model is capable of analyzing the performance of TRISO coated fuel particles with complicated multi-physics characteristics under the operation conditions of LWR,which is useful for further optimizing the FCM fuel design.