Laser-based maintenance apparatus using ultrasonic wave detection for flaw analysis and repair

• US 8,497,986 B2
• Filed: 04/23/2010
• Issued: 07/30/2013
• Est. Priority Date: 07/07/2005
• Status: Active Grant

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Ochiai, Makoto, Miura, Takahiro, Shimamura, Mitsuaki, Kuroda, Hidehiko, Osakata, Fukashi, Tsuchihashi, Kentaro, Yoshida, Masahiro
• Primary Examiner(s): Chowdhury, Tarifur
• Assistant Examiner(s): Lapage, Michael P
• Application Number:
  US12/766,475
• Publication Number:
  US 20100208248A1
• Time in Patent Office: 1,194 Days
• Field of Search: 356/237.1, 356/240.1, 356/241.1, 356/237.2, 356/502
• US Class Current: 356/237.2
• CPC Class Codes: F22B 37/003 Maintenance, repairing or inspecting equipment positioned in or via the headers
• CPC Class Codes: G01B 11/161 by interferometric means
• CPC Class Codes: G01B 17/02 for measuring thickness
• CPC Class Codes: G01B 2290/25 Fabry-Perot in interferometer, e.g. etalon, cavity
• CPC Class Codes: G01N 2291/0258 Structural degradation, e.g. fatigue of composites, ageing of oils
• CPC Class Codes: G01N 2291/02854 Length, thickness
• CPC Class Codes: G01N 2291/0421 Longitudinal waves
• CPC Class Codes: G01N 2291/2636 cylindrical from inside
• CPC Class Codes: G01N 29/043 in the interior, e.g. by shear waves
• CPC Class Codes: G01N 29/0645 Display representation or displayed parameters, e.g. A-, B- or C-Scan
• CPC Class Codes: G01N 29/07 by measuring propagation velocity or propagation time of acoustic waves
• CPC Class Codes: G01N 29/2418 using optoacoustic interaction with the material, e.g. laser radiation, photoacoustics photoacoustic cells G01N21/1702; measuring characteristics of vibrations by using radiation-sensitive means G01H9/00; acousto-optical conversion techniques for short-range imaging G01S15/8965; sound-producing devices using laser bundle G10K15/046
• CPC Class Codes: G21C 17/003 Remote inspection of vessels, e.g. pressure vessels
• 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 laser maintenance apparatus including a laser irradiation device which includes a first optical element for irradiating detection laser light on a test object to detect an ultrasonic wave; a second optical element for irradiating generation laser light on a test object so as to excite the ultrasonic wave; and an optical system container for containing the first and second optical element. The reflection direction of the first optical element and the reflection direction of the second optical element are arranged at an angle along the circumferential direction of the test object. The light reflected by the first optical element is irradiated at a position different than light reflected by the second optical element, and the laser irradiation positions of the light reflected by the first and second optical elements are different in the axial direction and the circumferential direction of the test object.

Claims

1. A laser maintenance apparatus configured to perform flaw detection, comprising:

a laser system including a laser light source and an optical system and emitting a laser light at an irradiation condition enabling flaw detection at 30 mJ or preventative maintenance at 60 mJ;

a light transmitting device configured to transmit the laser light emitted from the laser system; and

a laser irradiation device configured to irradiate the laser light transmitted by the light transmitting device to an object portion,

wherein the laser irradiation device includes;

a first optical element configured to irradiate detection laser light on a test object so as to detect an ultrasonic wave;

a second optical element configured to irradiate generation laser light on a test object so as to excite the ultrasonic wave by the irradiated detection laser light; and

an optical system container which contains the first optical element and the second optical element, wherein the reflection direction of the first optical element and the reflection direction of the second optical element are arranged at an angle along the circumferential direction of the test object, and light reflected by the first optical element is irradiated at a position different than light reflected by the second optical element, and the laser irradiation positions of the light reflected by the first and second optical elements are different in an axial direction and the circumferential direction of the test object, and

wherein the laser maintenance apparatus includes a processor configured to detect a crack in the test object as the flaw detection existing on the surface irradiated by the laser light.

2. The laser maintenance apparatus according to claim 1, wherein the reflection direction of the second optical element which reflects the generation laser light and the reflecting direction of the first optical element which reflects the detection laser light are arranged at an angle in the range of 30 to 60 degrees along the circumferential direction of the optical system container.

3. The laser maintenance apparatus according to claim 1, wherein the optical system container contains at least one or more light path altering elements.

4. The laser maintenance apparatus according to claim 3, wherein the light path altering element is composed of a lens and a wedge plate.

5. The laser maintenance apparatus according to claim 1, wherein the optical system container is formed in a spindle shape.

6. The laser maintenance apparatus according to claim 1, wherein the optical system container has a flow path.

7. The laser maintenance apparatus according to claim 1, wherein the first optical element and the second optical element are arranged so that the generation laser light and the detection laser light irradiate at symmetrical positions with respect to the axial direction of the optical system container.

8. The laser maintenance apparatus according to claim 1, wherein the first optical element is arranged at a top portion of the optical system container and the second optical element is arranged at a bottom portion of the optical system container with respect to the axial direction of the optical system container so as to prevent intersection of the generation laser light and the detection laser light.

9. The laser maintenance apparatus according to claim 1, wherein the laser irradiation device is rotated in a predetermined constant direction which is same as a fastening direction thereof.

10. The laser maintenance apparatus according to claim 1, wherein the laser irradiation device includes:

an optical fiber configured to transfer a generation laser light which generates an ultrasonic wave to the test object and a detection laser light which detects the ultrasonic wave to detect a flaw of the test object;

the first optical element configured to irradiate each of the generation laser light and the detection laser light, where the detection laser light is irradiated on the test object position while transmitting the generation laser light, and a reflective component of the detection laser light reflected from the test object portion is irradiated in the optical fiber;

the second optical element configured to irradiate the generation laser light which transmits light from the first optical element on the test object; and

an optical system container which is connected to one end of the optical fiber and contains the first optical element and the second optical element.

11. The laser maintenance apparatus according to claim 10, wherein the reflection direction of the second optical element which reflects the generation laser light and the reflecting direction of the first optical element which reflects the direction laser light are arranged at an angle in the range of 30 to 60 degrees along the circumferential direction of the optical system container.

12. The laser maintenance apparatus according to claim 10, wherein the optical system container contains at least one or more light path altering elements.

13. The laser maintenance apparatus according to claim 12, wherein the light path altering element is composed of a lens and a wedge plate.

14. The laser maintenance apparatus according to claim 10, wherein the optical system container is formed in a spindle shape.

15. The laser maintenance apparatus according to claim 10, wherein the optical system container has a flow path.

16. The laser maintenance apparatus according to claim 10, wherein the first optical element and the second optical element are arranged so that the generation laser light and the detection laser light irradiate at symmetrical positions with respect to the axial direction of the optical system container.

17. The laser maintenance apparatus according to claim 10, wherein the first optical element is arranged at a top portion of the optical system container and the second optical element is arranged at a bottom portion of the optical system container with respect to the axial direction of the optical system container so as to prevent intersection of that the generation laser light and the receiving laser light.

18. The laser maintenance apparatus according to claim 1, wherein the reflection direction of the second optical element is away from the reflection direction of the first optical element.

19. The laser maintenance apparatus according to claim 10, wherein the laser irradiation device performs irradiation on an inner surface of a cylindrical member of the test object.

20. The laser maintenance apparatus according to claim 1, wherein the processor of the laser maintenance apparatus is configured to detect a position and depth of the crack based on a reflection of the ultrasonic wave.

21. The laser maintenance apparatus according to claim 1, wherein the first optical element and the second optical element are arranged in this order, in laser advancing direction.

22. The laser maintenance apparatus according to claim 1, wherein the generation laser passes through the first optical element and is reflected by the second optical element.