JPS62108219A - Device for inspecting inside surface of pipe - Google Patents

Abstract

PURPOSE:To shorten the time for inspection and to obtain a sharp image by housing an illuminating means, solid stage image pickup camera, reflection mirror and optical system into a case and making the case freely glidable in a pipe to be inspected. CONSTITUTION:The irradiated light is reflected by the reflective surface 7a of the reflection mirror 7 when light is irradiated from a light 6 on the reflective surface 7a. The reflected light thereof transmits transmission glass 4 and irradiates the inside surface of the pipe 1 to be inspected. The irradiated light illuminates the inside surface of the pipe 1. The light of the inside surface image again transmits the glass 4 and is reflected by the reflective surface 7a of the reflection mirror 7, from which the light passes a narrow angle lens 8 and is made incident on the objective face 10a of a CCD camera 10. The image on the inside surface condition of the pipe is picked up by the camera 10 and the video signal thereof is processed with an image processor and is displayed on a television monitor. The entire periphery of part of the inside surface of the pipe 1 is thus made visible at a glance.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a tube inner surface inspection device used for inspecting the inner surface of a long and thin tube such as a cladding tube of a fuel rod in a nuclear reactor.

[Prior art]

A large number of fuel assemblies are housed inside the core of a PWR (pressurized light water burner), which is a type of power reactor, and each fuel assembly is composed of a large number of fuel rods.

This fuel rod has a large number of uranium dioxide pellets housed inside a hollow rod-shaped cladding tube made of Zircaloy alloy.

Now, when manufacturing the above-mentioned fuel rods, the inner surface of the cladding tube must be inspected for any flaws or defects.

Therefore, conventionally, the inner surface of the cladding tube has been inspected using a fiber scope, a Boer scope, or the like.

[Problem that the invention seeks to solve]

However, inspection using the above-mentioned fiberscope, borescope, etc. has the following problems.

(2) During inspection, the inner surface of the tube must be inspected one by one while rotating the tube, and it takes a lot of time to inspect all the milliliters inside the tube.

■ Illumination using fiberscope and borescope light guides cannot provide sufficient illumination of the inner surface of the tube.

■ Easily causes halation (clear images cannot be obtained).

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a tube inner surface inspection device that can shorten the inspection time of the tube inner surface, prevent halation, and obtain clear images.

[Means for solving problems]

This invention includes an illumination means, a solid-state image sensor camera, a reflecting mirror that guides light from the illumination means to the entire circumference of a part of the inner surface of the tube to be inspected, and a reflector that reflects the light diffusely reflected on the inner surface of the tube to be inspected to the solid state of the tube. The present invention is characterized in that an optical system leading to an image pickup device camera is housed in a circular case, and the case is slidable within the tube to be inspected.

[For production]

Since the entire circumference of a partial circular surface of the tube to be inspected is irradiated, the inspection can be efficiently performed without rotating the tube to be inspected. In addition, by arranging the direction of the light from the illumination means and the solid-state imaging/octad camera so that direct light and specularly reflected light do not enter the camera, halation can be prevented and clear images can be obtained.

[Implementation row]

FIG. 1 is a sectional view showing the structure of a first embodiment of the present invention. In this figure, reference numeral 1 indicates a tube to be inspected, and 2 indicates a cylindrical tube inner surface inspection device. In this pipe inner surface inspection device 2, 3 is a case formed of a light shielding member, and 4 is a case 3.
Transparent glass (or transparent plastic) is fitted into a part of the transparent glass 4, and a transparent electrode is embedded inside the transparent glass 4.

5.5... are guide balls attached to the surface of the tube inner surface inspection device 2, and the tube inner surface inspection device 2 slides on the inner surface of the tube 1 to be inspected by these guide poles 5,5....

6 is a light provided inside the end of the pipe inner surface inspection device 2;
Reference numeral 7 denotes a reflecting mirror having a shape in which the bottom surfaces of two cones are joined together, and this reflecting mirror 7 is fixed in contact with the transmitting glass 4. 8 is a narrow angle lens, 9.9 is a light shielding plate, 10 is a tube to be inspected 1
CCD (Charge Coup)
eed device) camera.

In the above configuration, when light is irradiated from the light 6 to the anti-reflecting surface a of the reflecting mirror 70, this irradiated light is reflected by the reflecting surface 7a, and this reflected light is transmitted through the transmitting glass 4 and illuminates the inner surface of the tube 1 to be inspected. The irradiated light illuminates the inner surface of the tube 1 to be inspected. The light of this inner image passes through the transmission glass 4 again, is reflected by the reflection surface 7b of the reflection mirror 7, and enters the objective dB 10a of the CCD camera 1o through the narrow angle lens 8. The CCD camera captures an image of the inner surface of the tube, and the video signal is processed by an image processing device and displayed on a television monitor. Thereby, the entire circumference of a portion of the inner surface of the tube to be inspected 1 can be seen at a glance.

FIG. 3 shows an example of an image taken by a CCD camera. In this figure, numeral 11 indicates a flaw on the inner surface of the tube 1 to be inspected.

FIG. 2 is a sectional view showing the structure of a second embodiment of the present invention, and in this figure, parts corresponding to those in FIG. 1 are given the same reference numerals. Reference numeral 15 denotes a condenser lens for collimating the light emitted from the light 6, 16 a hollow cylindrical member that prevents the light passing through the condenser lens 15 from being diffused, and 17 a substantially conical light reflecting plate. , 18 is a wide-angle lens brought into contact with the back surface of the light reflecting plate 17.

In such a configuration, when the light 6 is turned on, the light passes through the wide-angle lens 15 and is reflected by the light reflecting plate 17.
This reflected light passes through the transmission glass 4 and illuminates the inner surface of the tube 1 to be inspected. This illumination light is diffusely reflected on the inner surface of the tube 1 to be inspected,
A circular image is created, and the light passes through the transmission glass 4 again and enters the object plane 10a of the CCD camera 100 through the wide-angle lens 18. However, similar to the first embodiment described above,
By displaying the imaging results of the CCD camera 10 on a television monitor, the entire circumference of a portion of the inner surface of the tube 1 to be inspected can be seen at a glance. FIG. 4 shows an example of an image taken by a CCD camera. In this figure, reference numeral 19 indicates a flaw on the inner surface of the tube 1 to be inspected.

[Effects of the Invention] As explained above, according to the present invention, ■ the inspection time between tubes is shortened, ■ the inside of the tube is sufficiently illuminated, ■ halation can be prevented and clear images can be obtained, etc. The effect of this can be obtained.

[Brief explanation of drawings]

FIGS. 1 and 2 are cross-sectional views showing the configurations of the first and second embodiments of the present invention, and FIGS. 6 and 4 are according to the first and second embodiments of the present invention, respectively. It is a figure which shows the imaging result of the inner surface of the pipe|tube 1 to be inspected. DESCRIPTION OF SYMBOLS 1...Pipe to be inspected, 2...Pipe interior roof inspection device, 4...Transparent glass, 5...Guide ball, 6...・Light, 7...Reflector, 8...Narrow angle lens, 9...Shade plate,
10... CCD camera, 15... Sunlight lens, 17... Light reflecting plate, 18...
Wide angle lens.

Claims (1)

[Claims] an illumination means, a solid-state image sensor camera, a reflecting mirror that guides light from the illumination means to the entire circumference of a partial inner surface of the tube to be inspected, and a reflector that directs the light reflected on the inner surface of the tube to be inspected to the solid-state image sensor camera. A tube inner surface inspection apparatus characterized in that a guiding optical system is housed in a case, and the case is slidable within the tube to be inspected.