蒸汽发生器传热管凹痕与缺陷的涡流检测信号分析

Eddy current detection signal analysis of dents and defects in heat transfer pipes of steam generators

国内某核电站蒸汽发生器传热管涡流检测时发现部分可疑信号,不能确定其缺陷类型,故设计和制作了模拟试件,采用轴绕式差分探头对模拟试件进行涡流检测对比试验,同时采用旋转探头、阵列探头进行复核,模拟常规超声无法有效分辨该信号时的解决方法。试验结果表明,该缺陷信号不是单纯的凹痕信号,而是凹痕与缺陷的复合信号,对于类似信号可通过混频的方式消除其中的干扰变量从而达到区分和定量的目的。

During the eddy current detection of the heat transfer pipe of a steam generator in a domestic nuclear power plant, some suspicious signals were found, and the type of defect could not be determined. Therefore, a simulated sample was designed and fabricated, and axial differential probe was used to carry out eddy current detection and comparison tests on the simulated sample. At the same time, rotary probes and array probes were used for review, which simulated conventional ultrasonic is impossible. The solution when effectively distinguishing the signal. The test results show that the defect is not just a dent signal, but a compound signal of dent and defect. For similar signals, the interference variables can be eliminated by mixing frequency to achieve the purpose of differentiation and quantification.