SiC复合包壳瞬态条件下的热力学性能模拟

福岛事故后,核电站的安全成为首要关注的问题,耐事故燃料(ATF)在此背景下被提出来,并成为核燃料领域新的研究热点,SiC因其优良的辐照稳定性和耐腐蚀性能成为ATF重要的候选包壳材料。SiC复合包壳在结构形式和材料属性方面与Zr合金包壳存在显著差异,现有燃料性能分析程序/方法主要是针对锆-二氧化铀燃料系统开发的,不适用于SiC复合包壳的性能模拟或分析评价。本文采用有限元分析方法,模拟了SiC复合包壳在稳态和瞬态下的热力学行为。模拟结果显示,稳态条件下反应堆运行到70d时,包壳温度达到稳定状态,同时内外表面应力达到最大值;功率瞬态导致包壳内外表面温度升高,同时应力分布也对应出现明显变化。

A f ter the Fukushima nuclear accident,the safet y of NPP is become the f irst consideration for its development.The accident tolerant fuel(ATF)is proposed in this context,and become a new research hotspot.Because of the excellent irradiation stability and corrosion resistance,SiC composites become an attractive candidate cladding material for ATF.There are many differences between SiC composites cladding and Zr alloy cladding,so the performance models or analysis methods are not available for SiC composites cladding.In this paper,the Finite element method is used to analyze the performance of SiC composites cladding under normal and transient conditions.The results showed that the temperature was stable and the maximum hoop stress was reached when the time is about 70d under normal condition.The power ramp can let the cladding temperature increase and has visible inf luence on the stress distribution.