在役含共线裂纹核级设备的安全评估方法研究

Study on Safety Assessment Method for In-service Nuclear Equipment with Collinear Cracks

对在役核级设备进行安全评估时,现有技术规范依据COD理论、应力强度因子或J积分理论对单一裂纹缺陷进行安全评估。在多种载荷因素作用下,在役核级设备局部区域疲劳失效大多是裂纹的群体行为,在裂纹扩展过程中,相互影响,且裂纹数量及扩展路径具有很大的随机性和分散性。大量实验表明,多裂纹疲劳损伤问题止裂效果差,且破坏名义载荷因素小。就主副共线裂纹的疲劳扩展行为进行研究,提出在役含共线主副裂纹的核级设备的剩余寿命计算方法,该计算方法考虑主副裂纹扩展行为的相互影响。

The existing technical specifications are based on the COD theory, the stress intensity factor or the J integral theory to evaluate the safety of the single crack defects. Under the action of a variety of load factors, the fatigue failure in the local area of the nuclear equipment is mostly the mass behavior of the crack, which affects each other during the crack growth process, and the number and propagation path of the crack are of great randomness and dispersion. A large number of experiments show that the fatigue crack damage effect of multiple cracks is poor, and the nominal load factor is small. In this paper, the fatigue propagation behavior of the primary and secondary cracks is studied, and the calculation method of residual life of the nuclear grade equipment in the service of a common linear main and auxiliary crack is proposed. The calculation method takes into account the interaction between the propagation behavior of the main and the secondary cracks.