基于非线性方法的核级双层容器及支承结构热棘轮效应研究  

Study on Thermal Ratchet Effect of Nuclear Double Walled Vessel and Its Supporting Structure Based on Nonlinear Method

作　　者：刘亚楠 莫亚飞[1] 高付海[1] 李晓轩 LIU Yanan;MO Yafei;GAO Fuhai;LI Xiaoxuan(China Institute of Atomic Energy,Beijing 102413,China;China Academy of Machinery Science and Technology Group,Beijing 100048,China)

机构地区：[1]中国原子能科学研究院,北京102413 [2]中国机械科学研究总院,北京100048

出　　处：《原子能科学技术》2024年第2期431-440,共10页Atomic Energy Science and Technology

摘　　要：核级双层容器承担一回路压力边界和一回路冷却剂“纵深防御”包容的双重安全功能,是高温反应堆本体常用的一种结构形式。然而内层容器在瞬态工况下温度变化剧烈,内外层容器之间导热性能差,内外温差大,热棘轮效应是可能的重要失效机制。本文通过建立核级双层容器及支承结构轴对称有限元模型,使用非线性方法分析其在热-机循环载荷作用下温度、应力和应变的响应,研究棘轮效应分布的规律和特征。结果表明:热棘轮效应显著,是该类容器的主要失效模式;热棘轮敏感区域分布具有多点式的特点,在内外层容器不同部位均有涉及;危险区域的塑性应变累积行为主要出现在循环温度载荷的降温阶段,应变增量随循环次数的增加逐步稳定。结论指出热棘轮效应是核级双层容器结构设计必须关注的重点问题,所建立的非线性分析方法是解决该问题的有效手段。本研究可为核级双层容器热棘轮分析以及一回路工况参数优化设计和应变监测测点布置提供重要方法指导。The nuclear double walled vessel is a common structural form of high temperature reactor body,which assumes the dual safety functions of primary pressure boundary and primary coolant“defense in depth”containment.However,the temperature of the inner container changes dramatically under transient conditions,and the thermal conductivity of the inner and outer containers is poor.The temperature difference in the radial direction(between the inner and outer containers)and the height direction of the double walled vessel is large,and the temperature of the double walled vessel is easy to appear in the phenomenon that the temperature of the inside is higher than that of the outside in the heating stage and the temperature of the inside is lower than that of the outside in the cooling stage.The temperature distribution of the double walled vessel is not uniform and the thermal deformation is not coordinated,the thermal ratchet effect is a possible important failure mode for the main discontinuous position of the nuclear double walled vessel.In this paper,a reasonable axisymmetric finite element model of a nuclear double walled vessel and its supporting structure was established,and the accuracy of the finite element model’s temperature and stress analysis was verified.The temperature field under transient conditions was calculated by considering the three heat transfer modes of conduction,radiation and convection.The nonlinear stress and strain response of the structure under the heat-mechanical cyclic load was analyzed by considering the elastic-plastic of the material and geometric large deformation of the structure.The law and characteristics of ratchet effect distribution were studied based on the above analysis results.The results show that the thermal ratchet effect is significant,which is the main failure mode of this type of vessel.The thermal ratchet sensitive zone which locates at the main connection position of the double walled vessel of the supporting structure has the characteristics of multi-point di

关 键 词：核级双层容器及支承结构 热棘轮 非线性方法 多点式分布 工况设计 

分 类 号：TL35[核科学技术—核技术及应用]