脉冲涡流检测中核电运行机组电磁干扰研究

Study on Electromagnetic Interference of the Pulsed Eddy Current Test for Operating Nuclear Power Plants

脉冲涡流主要应用于壁厚的腐蚀检测工作,因其可在带保温的情况下进行检测工作而受到无损检测行业的关注。由于脉冲涡流对于在役运行的核电机组的检测,更容易受到电磁环境的干扰,研究从脉冲涡流检测信号的频谱分析入手,论证了核电在役机组低频电磁场干扰对检测信号的强干扰作用。研究在役机组空间电磁干扰的频谱识别,并通过实验验证了其对脉冲涡流时域检测信号的影响。根据研究结果,提出用检测信号与空间参考信号作差,来消除空间电磁干扰的差分检测模式,可较好地抑制在役机组的电磁干扰问题。在核电机组运行状态下,通过现场实验验证了探头差分模式下脉冲涡流在役检测效果。

The pulse eddy current is mainly used in corrosion detection of wall thickness,and it is concerned by the non-calculation inspection industry because it can be detected under the insulation condition.Because pulsed eddy current detection of operating nuclear power plants is more susceptible to electromagnetic interference,the study starts from the spectrum analysis of pulsed eddy current detection signals,the strong interference effect of low frequency electromagnetic field interference on the detection signal of operating nuclear power plants is demonstrated.Then the spectrum of space electromagnetic interference of operating plants is identified and its influence on the pulse eddy current time domain detection signal is verified experimentally.A differential detection mode is proposed to eliminate the space electromagnetic interference by making the difference between the detection signal and the space reference signal,which can suppress the electromagnetic interference problem of the in-service unit.Finally,the in-service detection effect of pulsed eddy current in probe differential mode is verified by experiments under the operating state of nuclear power plant.