含周向内表面裂纹核电管道CEGB-R6选择2失效评定曲线研究

Study on CEGB-R6 Option 2 Failure Assessment Curve of Nuclear Power Pipeline with Circumferential Inner Surface Crack

针对CEGB-R6选择2失效评定曲线存在精度欠缺问题,从J积分估算方法入手,分析了含周向内表面裂纹管道的H 1(n)/H 1(n=1)与硬化指数n、裂纹尺寸的分布规律。基于先前提出的改进的EPRI-J积分估算方法,推导获得了改进的选择2失效评定曲线。采用实际核电一回路管道材料力学性能数据,将R6选择2失效评定曲线、改进的选择2失效评定曲线与不同裂纹尺寸对应的有限元失效评定曲线进行比较,结果表明改进的选择2曲线精度优于R6选择2曲线,解决了R6选择2曲线在特定情况下评价精度不足问题。

For the problem of lack of assessment precision when using CEGB-R6 option 2 failure assessment curve(FAC)under certain circumstances,starting from J integral estimation method,the distribution laws of H 1(n)/H 1(n=1)of pipelines with circumferential inner surface cracks with hardening exponent n and crack size were analyzed.Based on the modified EPRI-J integral estimation method,a modified option 2 FAC was derived.The R6 option 2 FAC and the modified option 2 FAC were compared with the finite element FACs corresponding to different crack sizes using the mechanical properties data of the pipeline material of a nuclear power circuit,the results show that the accuracy of the modified option 2 FAC was better than the R6 option 2 FAC,which solves the problem of lack of assessment precision of R6 option 2 FAC in specific situation.