控制棒检测中对显示信号判定技术的改进

针对控制棒涡流检测中出现的一个显示信号不能充分判定，制作了含有人造裂纹的试验样件，采用在涡流检测线圈中加入磁芯的磁饱和线圈，消除控制棒上可能存在的磁性影响。并将3点对中的涡流探头组件改进成6点对中，改善了检测条件，提高了检测的可靠性。试验研究和检测结果表明，在现有技术的前提下，穿过式线圈及点式涡流线圈均可检测出周向和轴向裂纹；穿过式线圈不能区分单个或多个裂纹，多个点式线圈存在实现这种区分的可能性；轴向裂纹的涡流信号明显，但结构信号可能会影响对周向裂纹的判伤。

Improvement of Indication Signal Evaluation in Control Rods In-service Inspection

Considering that an indication signal may not be evaluated certainly in Rod Cluster Control Assembly in-service eddy current test, the test specimen with artificial flaws were fabricated, the magnet core was installed in coil assembly to produce magnetic saturation coils in order to eliminate possible magnetic impact on the control rods, and 3-point centre aligned device was changed with 6-point center aligned device in coil assembly to improve the examination condition and enhance the inspection reliability. Test and examination results showed that the current inspection technique can detect the axial and circumferential flaws for both bobbin and pancake coils; for pancake coils, it can distinguish single or multiple flaws, but not for bobbin coils; and the eddy current signal was signified by axial flaws. However, structure signals sometimes were similar with circumferential flaw signals.