APPARATUS AND METHOD FOR SEARCHING EDDY CURRENT OF ELECTRIC HEAT TUBE USING MEASURING MAGNETIC PERMEABILITY IN STEAM GENERATOR

• US 20100301851A1
• Filed: 01/23/2007
• Published: 12/02/2010
• Est. Priority Date: 01/25/2006
• Status: Active Grant

• Current Assignee: Korea Atomic Energy Research Institute (Government of The Republic of Korea)
• Original Assignee: Korea Atomic Energy Research Institute (Government of The Republic of Korea)
• Inventors: Kim, Whung-whoe, Son, Derac, Jyung, Dae-hyuk, Ryu, Kwon-Sang, Park, Duck-Gun
• Granted Patent: US 8,283,918 B2
• Time in Patent Office: Days
• US Class Current: 324/240
• CPC Class Codes: B24B 49/105 using eddy currents
• CPC Class Codes: F22B 37/003 Maintenance, repairing or inspecting equipment positioned in or via the headers
• CPC Class Codes: G21C 17/017 Inspection or maintenance of pipe-lines or tubes in nuclear installations
• CPC Class Codes: Y02E 30/30 Nuclear fission reactors

Abstract

A detection apparatus for an eddy current in a heat generating tube using a permeability measurement method, and a method using the apparatus are provided. In the detection apparatus, a bobbin type probe acquires detection information with respect to a magnetic flux change by a magnetic phase occurring in the heat generating tube using a coil which is wound in an axis direction of at least one yoke located in a perpendicular direction with a bobbin of the bobbin type probe, and a material having a corresponding magnetic phase and a circumferential defect, which is difficult to be detected by the bobbin type probe, are detected based on the detection information.

Claims

1. A defect detection apparatus for an inside of a heat generating tube, the apparatus comprising:

a bobbin type probe forming a magnetizing force using a coil which is wound on at least one bobbin located in a circumferential direction to acquire first detection information to determine a defect of the heat generating tube; and

a yoke type probe forming a magnetizing force using a coil which is wound in an axial direction of at least one yoke located in a perpendicular direction with the at least one bobbin to acquire second detection information from the heat generating tube,

wherein the detecting apparatus determines a material by a magnetic phase, based on the second detection information.

2. The detection apparatus of claims 1, wherein the first and second detection information are information about a magnetic flux change over time.

3. The detection apparatus of claim 1, wherein an axial defect of the heat generating tube is determined according to the first detection information.

4. The detection apparatus of claim 1, wherein a circumferential defect of the heat generating tube is determined according to the second detection information.

5. The detection apparatus of claim 1, further comprising:

a signal processor processing the second detection information to generate a corresponding digital signal.

6. The detection apparatus of claim 5, wherein the signal processor detects a quadrature component with respect to the magnetic flux change which indicates the second detection information by referring to a phase of an external alternating current (AC) source, and generates data to determine the material according to the magnetic phase or the defect.

7. The detection apparatus of claim 5, wherein the signal processor comprises:

a voltage control circuit supplying a power to a first coil of the yoke type probe;

a magnetic sensor sensing the 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 a corresponding electric signal;

an amplifier amplifying the corresponding electric signal to a predetermined size; and

an analog to digital (AD) converter converting the output of the amplifier to the digital signal.

8. The detection apparatus of claim 7, wherein the magnetic sensor detects the quadrature component with respect to the magnetic flux change which indicates the second detection information and the amplifier amplifies the quadrature component.

9. The detection apparatus of claim 1, wherein the at least one yoke is located on an imaginary line which connects a central axis of the heat generating tube with an external contact point of the heat generating tube.

10. The detection apparatus of claim 1, wherein the at least one yoke is made of any one of a ferrite and an electric steel sheet (SiFe).

11. A defect detection method for an inside of a heat generating tube, the method comprising:

forming a first magnetizing force using a coil which is wound on at least one bobbin located in a circumferential direction;

sensing a change of the first magnetizing force, and acquiring first detection information to determine a defect of the heat generating tube;

forming a second magnetizing force by using a coil which is wound in an axial direction of at least one yoke located in a perpendicular direction with the at least one bobbin;

sensing a change of the second magnetizing force acquiring second detection information from the heat generating tube; and

determining a material by a magnetic phase, based on the second detection information.

12. The detection method of claim 11, wherein the first and second detection information are information of a magnetic flux change over time.

13. The detection method of claim 11, wherein an axial defect of the heat generating tube is determined according to the first detection information, and a circumferential defect of the heat generating tube is determined according to the second detection information.

14. A computer-readable storage medium storing a program for implementing the detection method of claims 11 through 13.