堆内构件螺栓辐照促应力腐蚀可靠性评估方法  

Reliability Evaluation Method of Stress Corrosion Accelerated by Irradiation of Bolts in Reactor Internals

作　　者：王仲辉[1] 胡朝威[1] 李燕[1] 孙博[2] WANG Zhong-hui;HU Chao-wei;LI Yan;SUN Bo(Science and Technology on Reactor System Design Technology Laboratory,Nuclear Power Institute of China,Sichuan Chengdu 610213,China;School of Reliability and Systems Engineering,Beihang University,Beijing 100191,China)

机构地区：[1]中国核动力研究设计院核反应堆系统设计技术重点实验室,四川成都610213 [2]北京航空航天大学可靠性与系统工程学院,北京100191

出　　处：《机械设计与制造》2024年第6期64-69,共6页Machinery Design & Manufacture

摘　　要：堆内构件连接螺栓所处工况环境恶劣,以辐照促进应力腐蚀开裂(IASCC)为代表的螺栓断裂失效事件时有发生,为了分析评估堆内构件螺栓的可靠性,提出了一种考虑螺栓IASCC失效的可靠性评估方法。首先,基于断裂力学理论中的应力强度因子准则,分别构建了SCC和IASCC失效的极限状态函数,并利用仿真分析方法求解函数中的最大等效应力。其次,考虑函数中各参数的不确定性,应用一次二阶矩法求解堆内构件连接螺栓的可靠度。最后,以堆内使用数量最多的M16型号螺栓为例进行计算分析。结果表明,断裂韧度与螺栓所受最大等效应力对螺栓可靠性的影响最大,裂纹扩展系数、裂纹扩展指数的影响次之,裂纹初始尺寸对可靠性的影响最小。此种评估方法可用于反应堆结构设计中各类连接螺栓的寿命预测及可靠性评估,也可以辅助确定反应堆结构安全检测周期和检测重点。The connecting bolts of the reactor vessel internals are located near the core area of the primary circuit of the PWR.Due to its long-term operation in harsh working environments,bolt fracture events represented by irradiation assisted stress corrosion cracking(IASCC)occur from time to time.In order to analyze and evaluate the reliability of internal component bolts,a consider-ation bolt IASCC failure reliability assessment method.First,based on the criterion of stress intensity factor in fracture mechanics theory,the limit state functions of SCC and IASCC failure are constructed respectively,and the maximum equivalent stress in the function is solved by simulation analysis method.Secondly,considering the uncertainty of each parameter in the function,the first-order second-moment method is used to solve the reliability of the connecting bolts of internal components.Finally,the M16 bolts used in the pile are used as an example for calculation and analysis.The results show that the fracture toughness and the max-imum equivalent stress on the bolt have the greatest impact on the bolt reliability,followed by the crack propagation coefficient and the crack propagation index,and the initial crack size has the smallest impact on the reliability.This evaluation method can be used for the life prediction and reliability evaluation of various connection bolts in the design of the reactor structure,and can also help determine the safety inspection period and inspection focus of the reactor structure.

关 键 词：螺栓 应力腐蚀 可靠性 堆内构件 辐照 反应堆结构 

分 类 号：TH16[机械工程—机械制造及自动化] TH131