Apparatus and method for searching eddy current of electric heat tube using measuring magnetic permeability in steam generator

A defect detection apparatus for an inside of a steam generator tubing in a nuclear reactor, the apparatus comprising:

• a bobbin type probe forming a magnetizing force using a coil which is wound in a circumferential direction on at least one bobbin to acquire first detection information to determine a defect of the steam generator tubing;
• a yoke type probe forming a magnetizing force using a coil which is wound in an axial direction on at least one yoke to acquire second detection information from the steam generator tubing,
• wherein the at least one yoke is located in a direction perpendicular with the at least one bobbin;
• and
• a signal processor for processing the second detection information to generate a corresponding digital signal, the signal processor further comprises:
• a voltage control circuit supplying a power to a first coil of the yoke type probe,
• a magnetic sensor sensing a magnetic flux change, having been formed on a second coil of the yoke type probe as a result of the supplying of the power to the first coil of the yoke type probe, and generating the second detection information, and
• an analog to digital (AD) converter converting the second detection information to generate the corresponding digital signal,
• wherein the defect detection apparatus determines a material at a location of the defect from a magnetic phase based on the first detection information and one or more of the corresponding digital signal and the second detection information.