JP2008116421A - Underwater inspection apparatus and method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an underwater inspection apparatus capable of detecting a defect even if an inspection object is located in the interior of a pipe or a narrow section underwater, and to provide an underwater inspection method. <P>SOLUTION: A vehicle 20 comprises a vehicle advancing system 21 positioned on the rear side and a camera 22 positioned on the front side, and a vehicle operator 14a can execute control with watching the image captured by the camera 22. An ultrasonic sensor (described later) is installed for the purpose of detecting a defect, and a scanner unit 23 for moving the sensor in the advancement direction of the vehicle 20 is fixed on turning plates 24a, 24b. The scanner unit 23 can be turned circumferentially about the advancement direction of the vehicle 20 by a scanner unit turning mechanism 25. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an underwater inspection apparatus and an underwater inspection method for performing ultrasonic inspection and eddy current flaw inspection of structures in water, and in particular, in a pressure vessel such as an annulus part and a lower part of a baffle plate constituting a nuclear reactor. The present invention relates to an underwater inspection apparatus and an underwater inspection method suitable for inspecting narrow spaces, pipes such as a primary coolant recirculation pipe (PLR pipe) and a jet pump.

  As a first conventional technique for inspecting narrow spaces and inside pipes, a water immersion type ultrasonic probe is installed at the center of the casing so as to have sensitivity in the longitudinal direction of the casing, An apparatus is known in which reflection mirrors that can be rotated in the sensitivity direction of a touch element are arranged obliquely and inspection of a pipe in any direction is possible depending on the rotation angle of the reflection mirror (see, for example, Patent Document 1).

  Further, as a second conventional technique, an apparatus for inspecting a diffuser side inner surface of a jet pump, which is one of in-reactor equipment, is known and is inserted from an inlet mixer to a diffuser side (for example, a patent) Reference 2 and Patent Document 3).

  Furthermore, although it is not an inspection technique inside the piping, an apparatus for individually inspecting a plurality of structures in the nuclear reactor from the outer surface is disclosed in, for example, Patent Document 4 for a jet pump and Patent Document 5 for a core spare purger. Etc. are known.

JP 7-333202 A JP 2001-281386 A JP 2006-84343 A JP 2001-13283 A JP 2002-148385 A

  In the thing of patent document 1, the diameter of piping and the diameter of the housing | casing in which a sensor is mounted are equivalent sizes, and the whole circumference is obtained by matching the central axis in which the sensor is mounted with the central axis of the piping. It becomes possible to inspect. However, in this shape, if the pipe is bent, the pipe cannot be bent. Therefore, in a pipe having a lot of bends, it is necessary to use a casing having a diameter sufficiently smaller than the pipe diameter. Furthermore, when the pipe diameter is large, when the sensor is placed on the central axis of the pipe, the inspection itself may not be possible because the signal does not propagate to the inner wall of the pipe.

  Patent Document 2 and Patent Document 3 are specialized in the inspection of the inner surface of the diffuser of the jet pump, and the circumferential position of the housing on which the sensor is mounted is fixed by a jig. Therefore, it is not suitable for pipes with different diameters or inspection in free space.

  The ones described in Patent Document 4 and Patent Document 5 are for inspecting internal defects from the outside of a structure such as a pipe, and are not suitable for an object that cannot be accessed from the outside.

  An object of the present invention is to provide an underwater inspection apparatus and an underwater inspection method capable of inspecting defects even when the inspection target is the inside of a pipe or a narrow part in water.

(1) In order to achieve the above-described object, the present invention provides a vehicle having a propulsion mechanism movable in water, a sensor for detecting a defect of an inspection object, and scanning the sensor in the longitudinal direction of the vehicle. A scanner unit, a scanner unit rotating mechanism for rotating the scanner unit about the longitudinal direction of the vehicle as a rotation axis, and a pressing thruster mechanism for pressing the scanner unit against the inspection object. It is a thing.
With such a configuration, it is possible to inspect for defects even when the inspection target is the inside of a pipe or a narrow part in water.

  (2) In the above (1), preferably, the scanner unit and the pressing thruster mechanism are fixed via a common structure, and the thrust generation direction of the pressing thruster mechanism is mounted on the scanner unit. The sensitivity direction of the sensor is kept parallel.

  (3) In the above (1), preferably, the sensor is at least one of an ultrasonic probe or an overcurrent flaw detector.

(4) To achieve the above object, according to the present invention, a propulsion mechanism provided in a beagle is driven, and a first unit for approaching an inspection object, a scanner unit, and a longitudinal axis of the vehicle as a rotation axis. A second procedure for driving the rotating scanner unit rotation mechanism to detect the defect of the inspection object and to make the sensitivity direction of the sensor directly face the inspection object; and the scanner unit to the inspection object A third procedure for driving a pressing thruster mechanism for pressing and pressing the sensor against the inspection object; a fourth procedure for driving the sensor and inspecting the inspection object; and the sensor, A fifth procedure for driving the scanner unit capable of scanning in the longitudinal direction of the vehicle and repeating the fourth procedure while changing the position of the sensor, and for inspecting the inspection object. It is obtained by way.
With this method, it is possible to inspect for defects even in water, even if the inspection target is the inside of a pipe or a narrow part.

(5) In order to achieve the above object, the present invention includes a first procedure for inspecting an entire inspection target region by an air inspection apparatus that inspects an inspection target from the outside, and the first procedure, A second procedure for re-inspecting an area determined to have a high possibility of a defect in the inspection object using an underwater inspection apparatus, and performing the inspection of the inspection object Is.
With this method, it is possible to inspect for defects even in water, even if the inspection target is the inside of a pipe or a narrow part.

  According to the present invention, it is possible to inspect defects in water even if the inspection target is the inside of a pipe or a narrow part.

  Hereinafter, the configuration of the underwater inspection apparatus according to the first embodiment of the present invention will be described with reference to FIGS. The present embodiment is applied to a defect inspection in a nuclear reactor, in particular, an apparatus for inspecting a PLR (Primary Loop Re-circulation System) pipe from the inner surface.

Initially, the inspection state by the underwater inspection apparatus by this embodiment is demonstrated using FIG.
FIG. 1 is an explanatory diagram of an inspection state by the underwater inspection apparatus according to the first embodiment of the present invention.

  In the nuclear reactor 1, there are structures such as a shroud 2, an upper grid plate 3, a core support plate 4, and a shroud support 5, and pipes such as a PLR pipe 6 are connected. In addition, an operation floor 7 that is a work space is provided in the upper part of the nuclear reactor 1, and a fuel changer 8 is provided in the upper part.

  The inspection vehicle 9 inserted into the pipe is connected to the control device 11 via the vehicle cable 10. The control device 11 supplies power for moving the inspection vehicle 9 in the water and navigating it, and transmits and receives inspection signals in order to perform defect inspection at the minimum inspection location. In addition, a display device 12 is connected to the control device 11 to display an image of a camera mounted as an imaging means on the inspection vehicle and to display an inspection result detected by the control device 11. Further, a controller 13 is connected to the control device 11 and is operated by the vehicle operator 14a.

  On the other hand, in order to monitor the navigation of the inspection vehicle 9 from the outside, the underwater ITV camera 15 equipped with a stereo camera is dropped to a position where the inspection vehicle 9 can be visually recognized. In this method, two underwater ITV camera operation cables 16 are connected to the underwater ITV camera 15 at an interval, and the underwater ITV camera 15 is suspended from above the fuel changer 8 with the underwater ITV camera operation cable 16. The ITV camera operator 14 b drops it into the water of the reactor 1. The video of the underwater ITV camera 15 is input to the control device 11 via the underwater ITV camera cable 17.

  The depth of the underwater ITV camera 15 dropped in the water can be changed by adjusting the length of the underwater ITV camera operation cable 16 to hang, and the position is supported by the underwater ITV camera operation cable 16 at that depth. Is done. The vertical and horizontal orientations of the underwater ITV camera 15 can be adjusted by operating the two underwater ITV camera operation cables 16 individually by the ROV operator 14b.

Next, the configuration of the inspection vehicle 9 that is the underwater inspection apparatus according to the present embodiment will be described with reference to FIGS.
FIG. 2 is a bottom view showing the configuration of an inspection vehicle that is an underwater inspection apparatus according to the first embodiment of the present invention. FIG. 3 is a bottom view showing a configuration of a scanner unit that constitutes a part of an inspection vehicle that is an underwater inspection apparatus according to the first embodiment of the present invention. FIG. 4 is a plan view showing a configuration of a scanner unit rotation mechanism that constitutes a part of an inspection vehicle that is an underwater inspection apparatus according to the first embodiment of the present invention. FIG. 5 is a left side view showing the configuration of the scanner unit rotation mechanism that constitutes a part of the inspection vehicle that is the underwater inspection apparatus according to the first embodiment of the present invention.

  FIG. 2 is a bottom view of the inspection vehicle 9. The vehicle body 20 has a vehicle propulsion mechanism 21 at the rear and a camera 22 at the front. The inspection vehicle 9 is propelled in the X-axis direction by the vehicle propulsion mechanism 21. The inspection vehicle 9 is configured such that the vehicle operator 14a can control it while checking the video of the camera 22.

  On the other hand, the inspection vehicle 9 includes a scanner unit 23 in order to realize defect inspection. As will be described later with reference to FIG. 3, the scanner unit 23 includes an ultrasonic sensor (described later). The ultrasonic sensor is scanned by the scanner unit 23 in the propulsion direction (X-axis direction) of the vehicle body 20. The scanner unit 23 is fixed to the rotating plates 24a and 24b. The rotating plates 24a and 24b are rotated around the X axis as a central axis by the scanner unit rotating mechanism 25. That is, the scanner unit 23 is also rotated around the X axis as a central axis by the scanner unit rotating mechanism 25.

  Next, the detailed structure of the scanner unit 23 will be described with reference to FIG. FIG. 3 is a bottom view of the inspection vehicle 9.

  The scanner unit 23 includes scanner unit pressing portions 30A and 30B at both ends, and maintains a pressing posture when pressing against an inspection symmetry plane (such as the inside of a pipe) using a pressing mechanism (described later).

  The rotational force of the sensor moving motor 31 is transmitted to the sensor moving screw 33 via the sensor moving gears 32a and 32b, and rotates the sensor moving screw 33. When the sensor moving screw 33 rotates, the sensor mounting portion 34 moves in the direction in which the inspection vehicle is propelled. An ultrasonic sensor 35 is attached to the sensor attachment portion 34. As the sensor moving motor 31 rotates, the ultrasonic sensor 35 can perform ultrasonic flaw detection on the inspection surface of the PLR pipe 6 shown in FIG. 1 while moving in parallel with the propulsion direction (X-axis direction) of the vehicle body 20. To. The sensor mounting portion 34 has two through holes, and one has a groove that matches the screw pitch of the sensor moving screw 33 cut into the through hole by tapping. The other is a hole through which the sensor attachment portion support shaft 36 for allowing the sensor attachment portion 34 to move without rotating.

  Next, the detailed structure of the scanner unit rotation mechanism 22 will be described with reference to FIGS. 4 and 5. FIG. 4 is a plan view of the inspection vehicle 9, and FIG. 5 is a left side view of the inspection vehicle 9.

  As shown in FIG. 4, the scanner unit rotation mechanism 22 includes a scanner unit rotation motor 40. The rotational force of the scanner unit rotation motor 40 is transmitted to the scanner unit rotation shaft 42 via the scanner unit rotation gears 41a and 41b. When the scanner unit rotation shaft 42 rotates, the scanner unit rotation gear 41c rotates. On the other hand, as shown in FIG. 5, a scanner unit rotating rack 43 is fixed to the outer periphery of the vehicle body 20 in a ring shape. The scanner unit rotating gear 41 c and the scanner unit rotating rack 43 are engaged. When the scanner unit rotation gear 41c rotates, the scanner unit rotation rack 43 is rotated.

  Here, the scanner unit 22 can rotate relative to the vehicle body 20. However, the vehicle main body 20 includes a rotation prevention weight (not shown) inside and a rotation prevention wing (not shown) at the rear, and as a result, the scanner unit 22 is connected to the X axis. Around the X axis.

  A guide rail 45 is attached to the outer periphery of the vehicle body 20 in a ring shape. The guide rail 45 is attached in parallel with the scanner unit rotating rack 43. The rotation guide 44 attached to the scanner unit rotation shaft 42 rotates along the guide rail 45. Furthermore, guide rollers 46A, 46B, and 46C are attached to the rotary plates 23a and 23b. As a result, stable rotation without backlash is possible.

  On the other hand, a thrust thruster mechanism including thrusters 49A and 49B and guards 47A and 47B is installed at positions symmetrical with respect to the traveling direction axis (X axis) of the vehicle body 20. As shown in FIG. 2, the rotational driving forces of the pressing thruster motors 48A and 48B are transmitted to the thrusters 49A and 49B by the bevel gears 50A and 50B, respectively, and rotationally drive them. When the thrusters 49A and 49B rotate, a propulsive force in the Z-axis direction is generated in FIG. 4, and the propulsive force, together with the vehicle body 20 and the scanner unit 22, has a function of pressing the ultrasonic sensor 35 against the inspection surface. Yes.

Next, with reference to FIGS. 6 and 7, the rotation of the PLR pipe 6 that is a pipe to be inspected in the underwater inspection apparatus according to the first embodiment of the present invention, the rotation of the inspection vehicle 9, and the positional relationship between the ultrasonic sensors 35 will be described. To do.
6 and 7 are left side views showing the positional relationship between the inspection vehicle, which is an underwater inspection apparatus according to the first embodiment of the present invention, and the inspection surface.

  As shown in FIG. 6, when the inspection surface of the PLR pipe 6 that is the pipe to be inspected is at the lower part, the scanner unit rotating mechanism 22 is operated so that the ultrasonic sensor 35 is on the lower side. Then, a thrust force in the Z-axis direction is generated by the thrusters 49A and 49B, and the scanner unit pressing portions 30A and 30B are pressed against the inner surface of the PLR pipe 6.

  On the other hand, as shown in FIG. 7, when the inspection surface is on the side, the scanner unit rotating mechanism 22 is operated so that the ultrasonic sensor 35 faces sideways. Then, a thrust force in the Y-axis direction is generated by the thrusters 49A and 49B, and the scanner unit pressing portions 30A and 30B are pressed against the inner surface of the PLR pipe 6.

  As described above, since the ultrasonic sensor 35 and the thrusters 49A and 49B, that is, the scanner unit 23 and the pressing thruster mechanism are fixed to the rotation plates 24a and 24b, which are common structures, the scanner unit rotates. When the ultrasonic sensor 35 is directed to the inspection surface of the pipe by the mechanism 25, it is possible to generate a pressing force by a thruster in that direction, so that the ultrasonic sensor can be pressed in any direction by a pair of thrusters 49A and 49B. Become.

Next, an inspection procedure in the pipe using the underwater inspection apparatus according to the first embodiment of the present invention will be described with reference to FIGS.
FIG. 8 is an explanatory diagram of an approach image of the underwater inspection apparatus according to the first embodiment of the present invention to the inspection target weld. FIG. 9 is an explanatory diagram of a sensing image of the inspection target weld of the underwater inspection apparatus according to the first embodiment of the present invention. FIG. 10 is an explanatory diagram of an image for converting the pressing direction in the pipe of the underwater inspection apparatus according to the first embodiment of the present invention. FIG. 11 is a flowchart showing an inspection procedure in the pipe using the underwater inspection apparatus according to the first embodiment of the present invention.

  As shown in FIG. 8, when there are a plurality of inspection target welds 51 a and 51 b inside the inspection target pipe 6, it is assumed that they are inspected in order. First, the inspection vehicle 9 is advanced to the first inspection object weld 51a using the propulsion mechanism of the inspection vehicle 9.

  Next, as shown in FIG. 9, the inspection is performed by scanning the ultrasonic sensor 65 in the axial direction of the pipe 6 while keeping the ultrasonic sensor 65 downward.

  Next, as shown in FIG. 10, the scanner unit rotating mechanism 22 is rotated to sequentially perform inspections in order to obtain a vehicle state (53a, 53b, 53c in FIG. 10) that matches the inspection angle.

  FIG. 11 shows a detailed operation procedure. When the inspection is started in step 60, the inner surface inspection of all the weld lines is performed in step 61. In the procedure, first, in step 62, the vehicle is sequentially approached to the target weld line, and in step 63, the entire circumference of the target weld line is inspected.

  In the all-round inspection, first, in step 64, the scanner unit rotation mechanism is operated so that the sensitivity direction of the ultrasonic sensor faces the target welding portion. However, immediately after approaching the target weld line, the sensor is directed directly downward and the process proceeds to the next step without operating the rotation mechanism.

  Next, in step 65, the pressing thruster mechanism 47 is driven and pressed against the wall surface. Further, in step 66, the scanner unit is driven, and in step 67, the target welded portion is ultrasonically inspected. Thereafter, in step 68, the robot leaves the wall surface.

  The operations from step 64 to step 68 are repeated until the inspection of one weld line is completed. Further, the operation from step 62 to step 68 is repeated until the inspection of all the weld lines is completed. When all the inspections are completed, the inspection is terminated in step 69.

  As described above, according to the present embodiment, regarding the movement of the sensor that performs the inspection, the vehicle's propulsion mechanism governs the rough movement of the vehicle in the longitudinal direction, and the movement of the vehicle in the direction perpendicular to the longitudinal direction of the vehicle. Is controlled by the scanner unit rotation mechanism and the pressing thruster mechanism, and the detailed movement of the vehicle in the longitudinal direction during inspection is controlled by the scanner unit, which enables inspection at any position and any angle in the water. . Therefore, it is possible to inspect for defects even when the inspection target is the inside of a pipe or a narrow part in water.

  Next, the configuration of the underwater inspection apparatus according to the second embodiment of the present invention will be described with reference to FIGS. This embodiment is also applied to an apparatus for inspecting defects in a nuclear reactor, in particular, a PLR (Primary Loop Re-circulation System) pipe from the inner surface.

  About the underwater inspection apparatus of this embodiment, it is the same as that of what was shown in FIGS. 1-10 in 1st Embodiment. The present embodiment has a configuration in which an ultrasonic inspection from the outer surface of the pipe is combined with an ultrasonic sensor from the inner surface of the pipe. Ultrasonic inspection from the pipe outer surface is a widely practiced technique. The difference between the present embodiment and the first embodiment is only that the ultrasonic inspection is performed from the outer surface and the inspection procedure including the ultrasonic inspection. Therefore, only different points will be described.

  FIG. 12 is an explanatory diagram of an image of external weld line inspection according to the second embodiment of the present invention. FIG. 13 is an explanatory diagram of an image of a weld line inspection from the inside by the underwater inspection apparatus according to the second embodiment of the present invention. FIG. 14 is a flowchart showing the procedure of the weld inspection according to the second embodiment of the present invention.

  FIG. 12 shows an outline of ultrasonic inspection from the pipe outer surface. The external sensor 70 is connected to an inspection device (not shown) by an external sensor cable 71, and performs inspection while making a preparation shift in the circumferential direction of the inspection target weld line 51a. Here, when the defect 72 is found, the circumferential position 73 of the defect is recorded. Thereafter, as shown in FIG. 13, an ultrasonic inspection is performed on the defect 72 from the inner surface using the inspection vehicle 9.

  FIG. 14 shows a detailed operation procedure. When the inspection is started in step 80, the outer surface inspection of all the weld lines is performed in step 81.

  In the procedure, first, in step 82, the target weld line is sequentially moved, and an ultrasonic sensor is applied to the reference position of the target weld line. Since this reference position is a start and end point in the next round-trip inspection in step 83, it does not need to be specified in particular.

  Next, in step 83, the entire circumference of the target weld line is inspected. In the all-round inspection, in step 84, an ultrasonic inspection is manually performed in the axial direction of the target weld line. If it is determined in step 85 that there is a suspicion of a defect, in step 86, the number N of the weld line is determined. The pressing angle θ is recorded.

  Next, in step 87, the pressing angle is shifted by a predetermined shift angle Δθ. The weld line to be inspected is changed, starting from the starting point, and when the accumulation of Δθ exceeds 2π, that is, once, the entire circumference inspection of the weld line is finished. change.

  Until the inspection of all the weld lines is completed, the operations from Step 82 to Step 88 are repeated. When all the inspections from the outside are completed, if it is determined in Step 89 that there is a suspicious portion, Step 90 is performed. Then, a confirmation inspection will be conducted at that point.

  The procedure is as follows. First, in step 91, the vehicle is brought close to the target weld line, and in step 92, the scanner unit rotation mechanism is operated so that the sensitivity direction of the sensor faces the suspected defect angle. In step 93, the pressing thruster mechanism 47 is driven and pressed against the wall surface. Further, in step 94, the scanner unit is driven, and in step 95, the target welded portion is ultrasonically inspected. Thereafter, in step 96, the robot leaves the wall surface.

  The operation from step 91 to step 96 is repeated until the inspection of the suspicious part is completed. When the confirmation inspection of all the parts is completed, the process is completed in step 97.

  According to the present embodiment, it is possible to inspect for defects even when the inspection target is the inside of a pipe or a narrow part in water.

  In addition, it becomes possible to confirm defects that could not be achieved only by conventional ultrasonic inspection from the outside. The ultrasonic sensors of the first and second embodiments mainly detect the size of the defect in the depth direction.

Next, the configuration of the underwater inspection apparatus according to the third embodiment of the present invention will be described with reference to FIG.
FIG. 15 is a bottom view showing the configuration of the sensor unit of the underwater inspection apparatus according to the third embodiment of the present invention. The parts shown in the same manner as FIG. 3 show the same configuration.

  In this embodiment, an eddy current flaw detection sensor 98 is used instead of the ultrasonic sensor 35 shown in FIG. That is, as shown in FIG. 15, the ultrasonic sensor 35 in FIG. 3 is replaced with an eddy current flaw detection sensor 98, and the configuration of other devices is the same as that of the first embodiment.

  According to the present embodiment, the eddy current flaw detection sensor 98 can detect the size of the defect in the length direction.

Next, the configuration of the underwater inspection apparatus according to the fourth embodiment of the present invention will be described with reference to FIG.
FIG. 16 is a bottom view showing the configuration of the sensor unit of the underwater inspection apparatus according to the fourth embodiment of the present invention. The parts shown in the same manner as FIG. 3 show the same configuration.

  In this embodiment, instead of the ultrasonic sensor 35 shown in FIG. 3, a multi-sensor 99 including both the ultrasonic sensor 99B and the eddy current flaw detection sensor 99A is used. That is, as shown in FIG. 16, the ultrasonic sensor 35 in FIG. 3 is replaced with a multi-sensor 99, and the configuration of other devices is the same as that of the first embodiment.

  According to the present embodiment, the multi-sensor 99 can simultaneously detect the size in the depth direction of the defect and the size in the length direction of the defect.

  Since each embodiment of the present invention is as described above, each embodiment of the present invention includes an invention having the following features. That is, the first invention includes a vehicle having a propulsion mechanism movable in water, a sensor for detecting a defect of an inspection object, a scanner unit operable at least in the longitudinal direction of the vehicle, and the scanner. The unit includes a scanner unit rotation mechanism that rotates the longitudinal direction of the vehicle as a rotation axis, and a pressing thruster mechanism that presses the scanner unit against the inspection object.

  According to a second aspect of the present invention, the scanner unit and the pressing thruster mechanism are configured so that the thrust generation direction of the pressing thruster and the sensitivity direction of the sensor mounted on the scanner unit are kept parallel to each other. Is characterized by being configured to be fixed via a common structure.

  According to a third invention, in the first invention, the sensor is at least one of an ultrasonic probe or an overcurrent flaw detector.

  According to a fourth aspect of the present invention, there is provided a first procedure in which the underwater inspection apparatus according to any one of the first to third aspects of the invention is used, the propulsion mechanism of the first aspect of the invention is driven, and the inspection object is approached. A second procedure of driving the scanner unit rotation mechanism of the invention of claim 1 to directly face the direction of sensitivity of the sensor to the inspection object; and driving the pressing thruster mechanism of the first invention of making the sensor an inspection object A third procedure for pressing the object, a fourth procedure for driving the sensor of the first invention to inspect the inspection object, and driving the scanner unit of the first invention to determine the sensor position. While changing, the inspection is performed from the fifth procedure in which the fourth procedure is repeated.

  5th invention uses the air test | inspection apparatus which test | inspects a test object from the outside, and the underwater test | inspection apparatus in any one of 1st to 3rd invention, In the said air test | inspection apparatus, the whole test object area | region is carried out. A first procedure for inspecting, and a second procedure for re-inspecting, using the underwater inspection apparatus, for an area determined to have a high possibility that the inspection object is defective in the first procedure; From the above, the inspection is carried out.

  Each invention having such characteristics exhibits the following effects. That is, according to the first invention, the inner surface of the pipe can be inspected by contact or proximity sensor such as ultrasonic inspection or eddy current flaw detection without corners.

  According to the second invention, the sensor of the first invention can be pressed directly against the inspection target portion, which can contribute to improvement of inspection accuracy.

  According to the third invention, sizing in the depth direction of the defect or the length direction of the defect can be selectively detected.

  According to the fourth invention, the same effects as those of the first to third inventions can be obtained.

  According to the fifth aspect of the present invention, it is possible to check the defect as compared with the case where the conventional inspection has been made only from the outside, which can contribute to the improvement of the reliability.

It is explanatory drawing of the test | inspection state by the underwater test | inspection apparatus by the 1st Embodiment of this invention. It is a bottom view showing composition of an inspection vehicle which is an underwater inspection device by a 1st embodiment of the present invention. It is a bottom view which shows the structure of the scanner unit which comprises some inspection vehicles which are the underwater inspection apparatuses by the 1st Embodiment of this invention. It is a top view which shows the structure of the scanner unit rotation mechanism which comprises some inspection vehicles which are the underwater inspection apparatuses by the 1st Embodiment of this invention. It is a left view which shows the structure of the scanner unit rotation mechanism which comprises some inspection vehicles which are the underwater inspection apparatuses by the 1st Embodiment of this invention. It is a left view which shows the positional relationship of the inspection vehicle which is the underwater inspection apparatus by the 1st Embodiment of this invention, and an inspection surface. It is a left view which shows the positional relationship of the inspection vehicle which is the underwater inspection apparatus by the 1st Embodiment of this invention, and an inspection surface. It is explanatory drawing of the approach image to the test object welding part of the underwater inspection apparatus by the 1st Embodiment of this invention. It is explanatory drawing of the sensing image of the test object welding part of the underwater inspection apparatus by the 1st Embodiment of this invention. It is explanatory drawing of the image which converts the pressing direction in the piping of the underwater inspection apparatus by the 1st Embodiment of this invention. It is a flowchart which shows the inspection procedure in piping using the underwater inspection apparatus by the 1st Embodiment of this invention. It is explanatory drawing of the image of the weld line inspection from the outside by the 2nd Embodiment of this invention. It is explanatory drawing of the image of the welding line inspection from the inside by the underwater inspection apparatus by the 2nd Embodiment of this invention. It is a flowchart which shows the procedure of the welding part test | inspection by the 2nd Embodiment of this invention. It is a bottom view which shows the structure of the sensor part of the underwater inspection apparatus by the 3rd Embodiment of this invention. It is a bottom view which shows the structure of the sensor part of the underwater inspection apparatus by the 4th Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Reactor 2 ... Shroud 3 ... Upper lattice board 4 ... Core support plate 5 ... Shroud support 6 ... PLR piping 7 ... Operation floor 8 ... Fuel changer 9 ... Inspection vehicle 10 ... Vehicle cable 11 ... Controller 12 ... Display device 13 ... Controller 14a ... Vehicle operator 14b ... Underwater ITV camera operator 15 ... Underwater ITV camera 16 ... Underwater ITV camera operation cable 17 ... Underwater ITV camera cable 20 ... Vehicle body 21 ... Vehicle propulsion mechanism 22 ... Camera 23 ... Scanner unit 24a, 24b ... rotating plate 25 ... scanner unit rotating mechanism 30 ... scanner unit pressing part 31 ... sensor moving motors 32a, 32b ... sensor moving gear 33 ... sensor moving screw 34 ... sensor mounting part 35 ... ultrasonic sensor 36 ... Sensor mounting part support shaft 4 ... Scanner unit rotation motors 41a, 41b, 41c ... Scanner unit rotation gear 42 ... Scanner unit rotation shaft 43 ... Scanner unit rotation rack 44 ... Rotation guide 45 ... Guide rail 46 ... Guide roller 47 ... Pressing thruster mechanism 48 ... Pushing thruster motor 50... Bevel gears 51 a and 51 b. Inspection welded portion 52. Sensor scanning direction 53 a, 53 b and 53 c... Vehicle state according to inspection angle 70. Defect circumferential position 98 ... Eddy current flaw detection sensor 99 ... Multi sensor

Claims (5)

A vehicle with a propulsion mechanism movable underwater;
A sensor for detecting defects in the inspection object;
A scanner unit capable of scanning the sensor in the longitudinal direction of the vehicle;
A scanner unit rotation mechanism for rotating the scanner unit with the longitudinal direction of the vehicle as a rotation axis;
An underwater inspection apparatus comprising a pressing thruster mechanism for pressing the scanner unit against the inspection object. The underwater inspection apparatus according to claim 1,
The scanner unit and the pressing thruster mechanism are fixed via a common structure, and the thrust generation direction of the pressing thruster mechanism and the sensitivity direction of the sensor mounted on the scanner unit are kept parallel. Underwater inspection device characterized by that. The underwater inspection apparatus according to claim 1,
The underwater inspection apparatus, wherein the sensor is at least one of an ultrasonic probe or an overcurrent flaw detector. A first procedure of driving a propulsion mechanism provided in the beagle to approach the object to be inspected;
A second procedure for driving a scanner unit rotating mechanism for rotating the scanner unit about the longitudinal direction of the vehicle as a rotation axis, and for causing a sensitivity direction of a sensor for detecting a defect of the inspection object to face the inspection object. When,
A third procedure of driving a pressing thruster mechanism for pressing the scanner unit against the inspection object, and pressing the sensor against the inspection object;
A fourth procedure for driving the sensor and inspecting the inspection object;
A fifth step of repeating the fourth step while driving the scanner unit capable of scanning the sensor in the longitudinal direction of the vehicle and changing the position of the sensor, and inspecting the inspection object An underwater inspection method characterized by being carried out. A first procedure for inspecting the entire inspection target area by an air inspection device that inspects an inspection target from the outside;
A second procedure for re-inspecting an area determined by the first procedure using an underwater inspection apparatus for a region that is determined to have a high possibility that the inspection object has a defect, and inspecting the inspection object An underwater inspection method characterized in that:

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