JP2500738Y2 - Pipe inner surface inspection device - Google Patents

Description

[Detailed description of the device]

[0001]

BACKGROUND OF THE INVENTION The present invention is mainly for inspecting the inner surface of a bulge portion (expanding portion) of a control rod guide tube in a skeleton assembly (support structure) that forms a supporting skeleton of a fuel assembly. Regarding the device.

[0002]

2. Description of the Related Art Conventionally, as this type of fuel assembly, the one shown in FIG. 6 has been known. In this figure, reference numeral 1
Reference numeral 2 denotes an upper nozzle and a lower nozzle which are vertically separated from each other, and a control rod guide pipe (hereinafter abbreviated as a guide pipe) 3 is provided between the upper nozzle 1 and the lower nozzle 2. It has been passed and fixed. A plurality of support grids 5 for supporting a large number of fuel rods 4 are fixed in the middle of these guide tubes 3 so as to be separated from each other in the vertical direction.

By the way, the guide tube 3 and the upper nozzle 1
Alternatively, the method of coupling with the support grid 5 is performed by interposing a sleeve therebetween and expanding the guide tube 3 outward. Then, in this case, it is checked whether or not there is an abnormality (a crack, a trace of peeling of the die plating, etc.) on the inner surface of the guide tube 3, particularly the inner surface of the expanded portion (bulge portion), and the side view borescope is provided inside the guide tube 3. Inserted, and inspected visually by the inspector.

[0004]

However, in the above-described conventional visual inspection of the inner surface of the guide tube 3, since the posture of the inspector during the inspection work is limited, the burden on the inspector is large. Moreover, there is a problem that workability is poor.

Therefore, the inventors of the present invention tried to make a monitor by using a television, but when trying to make a monitor by using a conventional borescope, halation is generated in an image, so that the inspection cannot be endured. It was

The present invention has been made in view of the above circumstances. An object of the present invention is to improve the borescope so that halation is unlikely to occur in an image and to be smoothly monitored by a television. (EN) Provided is a pipe inner surface inspection device capable of surely inspecting the inner surface of a pipe to be inspected.

[0007]

In order to achieve the above object, the present invention provides a borescope having a light projecting section and a light receiving section for receiving light emitted by the light projecting section, inside a tube to be inspected. In the pipe inner surface inspection device for inspecting the observation portion of the inner surface of the pipe to be inspected, the light projecting portion of the borescope is arranged so that the light from the light projecting portion is outside the observation portion of the inner surface of the pipe to be inspected. And a guide cap is attached to the borescope, and a notch is formed in the guide cap, while the wall surface of the notch of the guide cap is inspected from the light projecting part to the inspected part. The reflecting surface is such that the light after being reflected on the inner surface of the tube is further reflected and irradiates the observation portion on the inner surface of the tube to be inspected.

[0008]

In the pipe inner surface inspection apparatus of the present invention, the light emitted from the projecting portion of the borescope inserted in the pipe to be inspected is reflected on the inner surface of the pipe to be inspected and then mounted on the borescope. The light is reflected by the wall surface of the cutout portion of the guide cap, hits the observation portion on the inner surface of the pipe to be inspected, and the light receiving portion of the borescope receives this light, thereby suppressing the occurrence of halation.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described below with reference to FIGS.

In these drawings, reference numeral 10 is a guide tube 3.
Is a side-view borescope that is inserted into the side-view borescope 10.
A light receiving unit 12 that receives light from the light projecting unit 11 is provided side by side along the axis of the side-view borescope 10. Then, in order that the light emitted from the light projecting section 11 does not directly enter the light receiving section after being reflected by the inner surface of the guide tube 3, the light projecting section 11 projects light wider than the conventional interval between the light projecting section and the light receiving section. The distance between the unit 11 and the light receiving unit 12 is set, or the light projecting direction of the light projecting unit 11 is set to be shifted to the tip side of the side-view borescope 10.

A guide cap 13 having an outer diameter slightly smaller than the inner diameter of the guide tube 3 is attached to the tip of the side-view borescope. The tip portion 14 of the guide cap 13 is formed so as to have a tapered diameter and is closed. Further, the guide cap 13 is formed with a cutout portion 15 for exposing the light projecting portion 11 and the light receiving portion 12, and the cutout portion 15 of the side-view borescope 10 (guide tube 3) is formed. A pair of wall surfaces 16 parallel to the axis are reflection surfaces. A video camera is optically connected to the side-view borescope 10 so that the inner surface of the tube can be inspected by looking at the screen of the television receiving the video signal from the video camera.

When the inner surface of the guide tube 3, particularly the inner surface of the bulge portion 3a is inspected by using the tube inner surface inspection apparatus configured as described above, the guide cap 13 is attached to the tip of the guide tube 3. The side-view borescope 10 in this state is inserted. In this case, since the tip end portion 14 of the guide cap 13 has a reduced diameter and is formed in a tapered shape, the guide cap 13 can be easily inserted into the guide tube 3 and the tip end portion 14 can be easily inserted.
Is closed, the light projecting unit 11 and the light receiving unit 12 of the side-view borescope 10 are not displaced from the notch 15 and a smooth inspection can be performed.

In this state, as shown in FIGS. 2 and 3, when the light receiving portion 12 of the side-view borescope 10 reaches the bulge portion 3a of the guide tube 3, the light emitted from the light projecting portion 11 is Once reflected on the inner surface of the guide tube 3, the reflected light is reflected again on the pair of wall surfaces 16 of the cutout portion 15 of the guide cap 13 to illuminate the bulge portion 3a.
As a result, the light received by the light receiving unit 12 is not the light emitted from the light projecting unit 11 directly hitting the bulge portion 3a of the guide tube 3 and reflected, so that even if a television monitor is used, halation is produced. It does not occur, and the bulge portion 3a is securely formed.
Can be inspected. Further, since the inspection can be performed by viewing the screen of the television when inspecting the bulge portion 3a, it is not necessary to take an unreasonable posture during the inspection work as in the conventional case, and the workability is greatly improved. Further, since the distance between the guide tube 3 and the side-view borescope 10 is kept constant by the guide cap 13, a focused and clear image can be obtained without adjusting the focus.

Furthermore, since the television monitor can be realized, the image of the television can be recorded on a video or printed and stored. Further, by connecting an image processing device, it can be an automatic abnormality detection device, and by allowing an inspector to observe only the image that this automatic abnormality detection device has determined to be abnormal, it is possible to determine whether it is good or bad. Labor saving can be achieved.

If attached to the tip of a long borescope or a small television camera, the lower bulge portion can be inspected. Further, it goes without saying that the present embodiment can be used not only in the bulge portion but also in the usual inspection of the inner surface of a straight pipe.

[0016]

As described above, according to the present invention, the borescope having the light projecting section and the light receiving section for receiving the light emitted by the light projecting section is inserted into the tube to be inspected. In a pipe inner surface inspection device for inspecting an observation portion on the inner surface of a pipe, a light projecting portion of the borescope is arranged so that light from the light projecting portion is emitted to the outside of the observation portion on the inner surface of the pipe to be inspected. While arranging and mounting the guide cap on the bore scope, while forming a notch in the guide cap,
The wall surface of the cutout portion of the guide cap was provided with a reflecting surface for further reflecting the light after being reflected from the inner surface of the pipe to be inspected from the light projecting portion and irradiating the observation portion on the inner surface of the pipe to be inspected. Therefore, the light emitted from the projection part of the borescope inserted in the tube to be inspected is reflected on the inner surface of the tube to be inspected and then reflected on the wall surface of the notch part of the guide cap attached to the borescope. By hitting the observation portion on the inner surface of the tube to be inspected and receiving the light by the light receiving portion of the borescope, it is possible to suppress the occurrence of halation and to smoothly perform monitoring by a television. As a result, the inner surface of the pipe to be inspected can be reliably inspected, and workability can be improved, labor can be saved, and automation can be achieved. Also,
Since the guide cap can hold the positional relationship between the tube to be inspected and the borescope constant, a focused and clear image can be obtained without adjusting the focus of the borescope.

[Brief description of drawings]

FIG. 1 is a front view showing an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing an inspection state of a bulge portion.

FIG. 3 is a sectional view of FIG. 1;

FIG. 4 is a front view showing an example of a guide cap.

FIG. 5 is a sectional view of FIG. 4;

FIG. 6 is a front view of a fuel assembly.

[Explanation of symbols]

 3 Control rod guide tube (test tube) 3a Bulge section (expanded section) 10 Side view borescope 11 Light emitting section 12 Light receiving section 13 Guide cap 15 Notch section 16 Wall surface

Claims (1)

(57) [Scope of utility model registration request] 1. An observation unit for observing an inner surface of a pipe to be inspected by inserting a borescope having a light projecting unit for irradiating light and a light receiving unit for receiving light emitted by the light projecting unit into the pipe to be inspected. In the pipe inner surface inspection device for inspecting, the light projecting portion of the borescope is arranged so that the light from the light projecting portion is irradiated to the outside of the observation portion on the inner surface of the pipe to be inspected, and the bore. While mounting the guide cap on the scope and forming a notch in this guide cap, the light from the wall surface of the notch of the guide cap is reflected from the light projecting part on the inner surface of the pipe to be inspected. Then, the pipe inner surface inspection apparatus is characterized in that the inner surface of the pipe to be inspected has a reflecting surface which irradiates the observation portion.