碳化硅复合包壳稳态应力与失效概率分析  

The Static Stress Analysis and Failure Probability Calculation of the Silicon Carbide Composite Cladding

作　　者：郝祖龙[1] 易柏全 王升飞[1] 玉宇[1] HAO Zulong;YI Baiquan;WANG Shengfei;YU Yu(Beijing Key Laboratory of Passive Safety Technology for Nuclear Energy,North China Electric Power University,Beijing 102206,China)

机构地区：[1]华北电力大学非能动核能安全技术北京市重点实验室,北京102206

出　　处：《核科学与工程》2021年第4期810-817,共8页Nuclear Science and Engineering

基　　金：北京市自然科学基金资助项目(1192016);中央高校基本科研业务费专项资金资助(2020MS031)。

摘　　要：碳化硅(SiC)复合包壳是未来轻水堆耐事故燃料包壳候选方案之一。以三层和双层结构SiC包壳为研究对象,研究了稳态工况下SiC包壳的应力分布及失效概率估算问题。基于线弹性力学理论和材料辐照肿胀特性,考虑包壳内外压力差、径向温度梯度与辐照肿胀三种因素,并引入SiC复合材料假塑性行为,经合理简化后给出了适用于多层结构的包壳应力分布通用模型,通过比较模型解析解与数值模拟结果,验证了多层包壳应力计算模型的有效性。同时讨论了SiC复合包壳的层厚比对材料应力分布的影响。采用Weibull分布模型对寿期末高燃耗工况下的SiC包壳失效概率进行了估算,结果表明,双层SiC包壳的失效概率最低可达10^(-12),明显低于三层SiC包壳的失效概率,有助于SiC结构优化。同时,也验证了停堆工况时的环向和轴向应力激增。The design of the multi-layered silicon carbide(SiC)cladding is one of the research fields of the accident tolerant fuels(ATF)in the pressurized water reactor(PWR).This paper mainly studies the stress distribution of the three-layered SiC cladding and duplex SiC cladding under steady-state operations.Based on the theory of linear elasticity and properties of material irradiation swelling,the influence of internal and external pressure difference,the radial temperature gradient and irradiation swelling were considered,and the pseudo-plastic behavior of SiC composites was introduced.The stress calculation model for the multi-layer cladding structure is presented in this paper.Compared with the numerical simulation results,the validity of the model is verified and the influence of the thickness ratio on the stress distribution is discussed.The failure probability of the SiC package in the high burnable condition of the lifetime is calculated by using the improved Weibull distribution model.The results showed that the lowest failure probability of the duplex SiC cladding was 10^(-12),which was significantly lower than the failure probability of the three-layer SiC cladding,which could help the SiC structure optimization.At the same time,the surge of hoop and axial stress in the shutdown condition is verified.

关 键 词：压水堆 碳化硅包壳 复合材料 应力分布 失效概率 

分 类 号：TL352.1[核科学技术—核技术及应用]