JPH0516526Y2 - - Google Patents

Description

[Detailed explanation of the idea]

[0001]

[Industrial Application Field] This invention is a nuclear fuel rod for a pressurized water reactor (PWR) or a boiling water reactor (BWR). The present invention relates to an inspection device that can automatically detect defects caused by chips, cracks, adhesion of foreign matter, etc. that occur on the circumferential surface.

[0002]

[Prior Art] As a means for detecting defects on the circumferential side of this type of cylindrical body (including columns and cylinders),
Image processing using uniform light beams or diffused light beams has been considered, but when using this method, it is difficult to distinguish between defective areas and normal areas, that is, it is not possible to set a threshold value in image processing. Therefore, as a detection means that has been actually used in the past, as shown in FIG. The cylindrical body a is moved forward (in the front-rear direction of the drawing), and at this time, a light-receiving detector e made of a photoelectric element or the like is arranged on the radial line d of the cylindrical body a, and a light-receiving detector e, which is not shown in the figure, is placed on the diameter line d of the cylindrical body a. The incident light beam f from the optical device is irradiated to the intersection point g with the meridian d, and at this time, the incident light beam f is made to enter so as to obliquely intersect the tangent h at the intersection point g at a predetermined angle θ. Therefore, if there is no defect on the circumferential surface of the cylindrical body a, the reflected light beam will be directed in the direction of f' as shown in figure a, and the light will not be received by the photodetector e, indicating that there is a defect. Only then is the unusual reflected light therefrom detected by the light receiving detector e.

[0003] According to the above-mentioned detection means, since the cylindrical body a advances while rotating, the spot caused by the incident light beam f scans the circumferential side of the cylindrical body a in a spiral pattern, and the inspection can be performed over the entire area of the same side surface. In this case, using the same method, as shown in Figure 4.
As shown in b, if the axis b is displaced even slightly and shifts to b', the irradiation point of the incident ray f will be g' instead of g, and the reflected ray will be
f'', and this light is received by the light receiving detector e as noise.

[0004] As a result, the cylindrical body a, the light receiving detector e,
Each relative position of the incident light beam f is required to be adjusted with a fairly high degree of precision, and not only is it necessary to devote time and effort to the adjustment operation, but in reality, when the cylindrical body a is rotated, its center of rotation must be adjusted. Since it is difficult to create a configuration in which the signal does not vary at all, the so-called S/N ratio between the signal and the noise will also decrease.

[0005] Also, Japanese Patent Application Publication No. 57-57339, Japanese Patent Application Publication No. 54
-As specified in Publication No. 108687, light from an irradiation light source is irradiated as a spot light onto the surface of a cylindrical member to be inspected, the reflected light is received by a light receiving element, and this is analyzed by a detection circuit. As with the conventional example described above, correct inspection cannot be carried out if the center of rotation of the cylindrical body changes.

[0006]

[Problem to be solved by the invention] The present invention has been studied in view of the above-mentioned difficulties, and claim 1 of the invention states that the detector is sensitive only to light rays incident along the light receiving axis. In addition to using a one-dimensional light receiving element, the parallel optical axis of the irradiation curved surface irradiation on the circumferential side of the cylindrical body to be inspected is made perpendicular to the light receiving axis center line of the primary light receiving element, thereby making it possible to achieve a circular The purpose is to make it possible to suppress the generation of noise due to the displacement of the axis of the columnar body, to facilitate adjustment, and to obtain highly reliable test results.

[0007] Furthermore, in claim 2, in addition to the invention of claim 1, the rotation device of the cylindrical body is configured by a conveyance belt and a positioning guide plate that are appropriately arranged, so that the rotation of the cylindrical body is An attempt is being made to allow the columnar body to rotate and advance without causing any axial runout, to further improve the S/N ratio, and to improve the inspection efficiency of the columnar body.

[0008]

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a method for rotating a cylindrical body such as a nuclear fuel pellet in a desired direction around an axial center line. The configured rotation device,
A projector that irradiates parallel light within a predetermined area toward the peripheral side of the cylindrical body rotated by the rotation device; A nuclear fuel comprising a one-dimensional light-receiving element arranged so that its light-receiving axis substantially coincides with an imaginary line that is substantially orthogonal to the light beam and passes substantially through the axis of the cylindrical body. It is an object of the present invention to provide an automatic inspection device for defects on the circumferential side of a cylindrical object such as a pellet.

[0009] In the case of claim 2, the rotation device in claim 1 is a transportation device that places the cylindrical body and moves it toward the projector side, and is tilted so that the projector side is on the upper side. consisting of a belt, and a positioning guide plate disposed intersecting with the mounting surface of the conveying belt and having a rotating sliding contact surface with the cylindrical body,
Further, the guide plate is disposed above the conveyor belt so that its rotating sliding contact surface is obliquely arranged in a plan view with respect to the moving direction of the conveyor belt.

[0010]

[Operation] In the case of claim 1, the parallel light beam from the projector is incident on the irradiation curved surface which is the circumferential side of the rotating columnar body, and the reflected light here passes through the axis of the columnar body. The one-dimensional light-receiving element will only receive the light if it matches the virtual line.
Even if the cylindrical body moves in the direction of the imaginary line, the relative positional relationship between the parallel rays and the irradiation curved surface remains unchanged. Instead, there is a defect in the cylindrical body, and light enters for the first time.

[0011] Furthermore, even if the cylindrical body moves in a direction perpendicular to the above-mentioned imaginary line, the relative positional relationship between the parallel rays and the irradiation curved surface remains unchanged as described above, so in such a case There is no generation of unwanted noise, and defective portions can be detected correctly regardless of fluctuations in the cylindrical body.

[0012] According to claim 2, the conveyor belt operates in a tilted body in a predetermined transition direction, and
Since it is in contact with the positioning guide, the rotational position of the columnar body is not only maintained in a normal state, but also because the positioning guide and the direction of movement of the conveyor belt are in an oblique state, the columnar body is transferred toward the axis of the cylindrical body while rotating, and as a result, the cylindrical body is inspected for defects over its entire circumferential side surface, and is finally separated from the conveyor belt. Subsequent processing becomes easier.

[0013]

[Example] The present invention will be described in detail with reference to FIGS. 1 to 3. The present invention is equipped with a projector 1, a one-dimensional light receiving element 2, and an autorotation device 3, and the projector 1 is located within a predetermined area. In this case, the type of the light beam L may be light emitted from a tungsten filament light bulb, light emitted from a fluorescent lamp, or laser light, as long as it corresponds to the characteristics of the one-dimensional light receiving element 2 described later. , strobe light, infrared light, ultraviolet light, etc. can be used. In the invention of claim 1, a cylindrical body A such as a nuclear fuel pellet is rotated by an appropriate rotation device 3 that can rotate the cylindrical body A to the right or left so that its axis line B becomes the center. On the circumferential side A′ of
In the figure, parallel light beams L are irradiated from the projector 1 toward the upper half thereof, so that an irradiation curved surface S as shown in b in FIG. 1 is obtained.

[0014] The one-dimensional light-receiving element 2 has a light-receiving axis Y' that is substantially orthogonal to the parallel light beam L and a virtual line Y that passes through the axis of the cylindrical body A. They are arranged so that they substantially match. Here, in the one-dimensional light receiving element 2, when the parallel light ray L is reflected from the irradiation curved surface S on the circumferential surface A' of the cylindrical body A, the reflected light is substantially parallel to the virtual line Y. When there is a match,
It has the characteristic of being able to receive this reflected light, and therefore, in the state shown in FIGS. Even if
Unless there is a defective part W in A' as shown in c in Fig. 1,
No light enters the one-dimensional light-receiving element 2 and becomes a noise source.

[0015] Furthermore, as shown in FIG. 2, even if the cylindrical body A moves in the X-ray direction perpendicular to the virtual line Y, actually to the left, the relative relationship between the parallel ray L and the irradiation curved surface S in this case also changes. The positional relationship remains unchanged, and therefore, the reflected light as a whole only has a positional shift to the left and right, but the reflection direction is parallel movement, and as a result, no noise is generated.

[0016] Next, in the rotation device 3 according to claim 2, the cylindrical body A is placed and moved toward the projector 1, and is arranged at an angle so that the projector 1 side is on the upper side. conveyance belt 3a of the equipment, and the belt 3
The guide plate 3 is composed of a positioning guide plate 3d having a rotating sliding contact surface 3c with the cylindrical body A arranged at right angles to the mounting surface 3b of the cylindrical body A.
d is disposed above the conveyor belt 3a, and in this case, as shown in FIG.
It is arranged so that it is not orthogonal to the transition direction D of a, but obliquely in plan view.

[0017] Therefore, according to the above device, when the conveyor belt 3a is operated in the transfer direction D by a power source and a transmission mechanism (not shown), the cylindrical body A on the mounting surface 3b rotates in the direction of the arrow E. However, since the belt 3a is inclined at this time, it is positioned at a rotational position in contact with the rotational sliding contact surface 3c of the positioning guide plate 3d, and is also aligned with the arrow F in FIG. 3, that is, the axis of the cylindrical body A. It will move in the direction of line B, in other words, in the direction along the rotating sliding contact surface 3c, and after the cylindrical body A is inspected for the presence or absence of defects over its entire circumferential side, it leaves the conveyor belt 3a. Therefore, a transfer belt (not shown) is installed next to this to transport the inspected cylindrical body to a desired location, and also to move a predetermined sorting actuator etc. by the light reception signal from the one-dimensional light receiving element 2. This makes it possible to automate the removal of cylindrical bodies with defective parts.

[0018]

[Effect of the invention] Since the present invention is constructed as described above, according to claim 1,
If the cylindrical body is a nuclear fuel pellet, it is possible to prevent worker exposure to radiation compared to visual inspection of defective parts, eliminate inspection errors due to human fatigue, and standardize judgment criteria. In addition, there is no risk of noise generation due to displacement during inspection of cylindrical objects, and S/
Highly accurate inspection with excellent N ratio can be guaranteed with simple adjustment operations.

[0019] Furthermore, according to claim 2, the rotation of the cylindrical body is caused by driving an inclined conveyance belt,
Due to the arrangement of the positioning guide plate, it is possible to perform the inspection without causing any axial center line fluctuation, which makes it possible to obtain more reliable inspection results and to improve the oblique shape of the guide plate and the belt. The arrangement allows the cylindrical body to advance smoothly, making it convenient to automate the processing of inspected cylindrical bodies, and making it possible to provide an efficient device at a low cost.

[Brief explanation of the drawing]

FIG. 1A is a front explanatory view of an inspection apparatus according to a first aspect of the present invention, and FIGS. 1B and 1C are plan views showing how the apparatus irradiates a cylindrical object with and without a defect, respectively.

FIG. 2 is an explanatory front view of the inspection device according to claim 2.

FIG. 3 is a plan view of the device of FIG. 2 with the one-dimensional light receiving element removed.

FIG. 4 shows a conventional circumferential side defect inspection means for a cylindrical body, in which a is a normally adjusted state and b is an explanatory diagram of the principle in an incorrectly adjusted state.

[Explanation of symbols]

1... Floodlight 2...One-dimensional light receiving element 3...Rotation device 3a...Transportation belt 3b...Placement surface 3c...Rotating sliding contact surface 3d... Positioning guide plate A...Cylindrical body A′……peripheral side B...Axis center line D...Transition direction L...parallel rays S...irradiation curved surface Y...Virtual line Y′...Light receiving axis center line.

Claims (2)

[Scope of utility model registration request] [Claim 1] A cylindrical body such as a nuclear fuel pellet is
A rotation device configured to rotate in a desired direction about an axis, and a floodlight that irradiates a parallel beam of light within a predetermined area toward the circumferential side of the cylindrical body rotated by the rotation device. , on the side of the irradiated curved surface of the cylindrical body by the parallel rays, the light receiving axis line is substantially on an imaginary line that is substantially orthogonal to the parallel rays and substantially passes through the axis of the cylindrical body. 1. An automatic inspection device for defects on the circumferential side of a cylindrical object such as a nuclear fuel pellet, characterized by comprising a one-dimensional light-receiving element arranged so as to match the above. [Claim 2] A cylindrical body such as a nuclear fuel pellet,
A rotation device configured to rotate in a desired direction about an axis, and a floodlight that irradiates a parallel beam of light within a predetermined area toward the circumferential side of the cylindrical body rotated by the rotation device. , on the side of the irradiated curved surface of the cylindrical body by the parallel rays, the light receiving axis line is substantially on an imaginary line that is substantially orthogonal to the parallel rays and substantially passes through the axis of the cylindrical body. and a one-dimensional light-receiving element arranged to match the above, and the rotating device is configured to place the cylindrical body and move it toward the projector side, and the device is tilted so that the projector side is on the upper side. It consists of a conveyor belt, and a positioning guide plate that is arranged to intersect with the mounting surface of the conveyor belt and has a rotational sliding contact surface with the cylindrical body, and the guide plate has a rotational sliding contact surface with the cylindrical body. Automatic inspection for defects on the circumferential side of a cylindrical object such as a nuclear fuel pellet, characterized in that the surface is disposed above the conveying belt so that its surface is obliquely arranged in a plan view with respect to the transfer direction of the conveying belt. Device.