为了检出并可靠测量AP1000反应堆压力容器顶盖（RPVH）的表面缺陷，尤其是潜在降质机理一次侧应力腐蚀纵向裂纹，采用自制X型涡流探头对裂纹类缺陷开展了试验与CIVA仿真研究。结果表明：X型探头具有方向性，且对纵向和周向裂纹的检测灵敏度最高；在检测能力方面，可检出最短为1 mm，最小深度为0.2 mm的裂纹，当裂纹深度超过2.5~3 mm后，幅值增加趋于缓慢。最后将自制探头应用于AP1000顶盖的役前检查，以评价其综合性能，发现探头的信噪比、提离高度均能满足规范要求，测长与定位结果与实际相符。

Eddy current testing and CIVA simulation were carried out for various surface defects, especially PWSCC in reactor vessel head (RPVH) to determine the detection capability and the sizing rules of X-type point probe. X-type point probe can distinguish the direction of defects, and the axial and circumferential crack have the maximum defect responses. The minimum detection capability of depth and length is 0.2 mm and 1 mm receptively, and the signal amplitude increases slowly when depth is ≥2.5-3 mm. The method of -6 dB length measurement has also been verified and can be applied. X-type coil surface probes were applied in the AP1000 PRVH pre-service inspection for the first time to evaluate the integrated performance, including signal to noise ratio and the lift-off. The results satisfy the code, and the length measurement and position is precise.