JP2000009880A - Device and method for inspecting fuel assembly - Google Patents

Abstract

PROBLEM TO BE SOLVED: To judge whether a fuel assembly is acceptable or not inexpensively and remotely by performing the operation of image processing data, comparing the data with data being stored in advance, measuring the various kinds of dimensions of a portion to be inspected, or deciding the presence or absence or the like of scratch, contamination, adhesion of a foreign matter. SOLUTION: By rotating a specimen (a fuel assembly 170) being placed upright on a fuel inspection stand 100 is rotated around its axis, a surface to be inspected of the fuel assembly 170 is positioned accurately without any twisting. Data required for inspection are stored in advance by an image- inputting unit 200, data obtained by processing an output image from the image- inputting unit 200 is processed and the obtained data are subjected to operation and are compared with data being stored as needed, various kinds of dimensions of a site to be inspected are measured, or the presence or absence of a scratch, contamination, adhesion of foreign objects is decided. Then, the fuel assembly inspection stand 100, the image-inputting unit 200, and an image-processing unit 300 are controlled by a computer 400 for controlling an inspection device, thus judging whether the fuel assembly 100 is acceptable or not, and storing inspection data.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is suitable for a visual inspection and a dimensional inspection of a fuel assembly used for a nuclear reactor, especially a fuel assembly using a new fuel of Mixed Oxide Fuel (hereinafter abbreviated as MOX fuel). The present invention relates to a fuel assembly inspection device and an inspection method.

[0002]

2. Description of the Related Art With respect to a conventional uranium dioxide fuel assembly, when a new fuel is inspected in a plant, no radiation is emitted from the fuel. Therefore, the fuel assembly is moved up and down on a fuel inspection table, and is manually operated by a fuel inspector. The fuel assembly was rotated, and the fuel inspector visually inspected using the fuel inspection jig held by the fuel inspector.

[0003] Japanese Patent Application Laid-Open No. 3-111796 discloses a technique in which a plurality of TV cameras are installed and non-contact dimension measurement is performed. Also, JP-A-4-30179
Japanese Patent Application Laid-Open No. 8 (1994) discloses a technique for inspecting a fuel rod or the like using a fixed focus camera and a mechanism for moving the camera left and right, up and down, and back and forth.

Further, Japanese Patent Application Laid-Open No. 8-262180 discloses a technique for performing an appearance inspection using an inspection table, a camera, and illumination. Japanese Patent Application Laid-Open No. 8-54491 discloses a technique for measuring the perpendicularity between an upper tie plate and a fuel rod by a mechanical method.

[0005]

However, since the MOX fuel described above emits radiation from the fuel even in the case of a new fuel and cannot be approached by an inspector from the viewpoint of avoiding exposure, the inspection device and the inspection device by remote control are required. Testing methods had to be developed.

Further, according to the technique described in Japanese Patent Application Laid-Open No. 3-111796, the number of cameras increases and the camera becomes expensive. In addition, since an illumination method that is important when photographing with a camera is not disclosed, it is necessary to develop an illumination method that is effective for the technology.

On the other hand, according to the technique described in Japanese Patent Application Laid-Open No. Hei 4-301798, the visual inspection is performed by a person who looks at the camera image and is inspected, so that labor is not saved. Measure the distance with a dedicated position detection device,
Since the measurement is performed by obtaining an actual dimension corresponding to the dimension on the image stored in the memory of the control device corresponding to the distance, a special device such as the position detecting device is required, which increases the cost and lowers the reliability. In addition, some other method is required for measuring the perpendicularity between the upper tie plate and the fuel rod.

According to the technique described in Japanese Patent Application Laid-Open No. 8-262180, the inspection is performed by the inspector observing the image of the camera, so that labor cannot be saved. There is a need. Further, Japanese Patent Application Laid-Open No. 8-54
According to the technology described in Japanese Patent No. 491, a mechanical measuring device is required in addition to a camera, which is very expensive. Therefore, a method of measuring the perpendicularity between the upper tie plate and the fuel rod only by the camera image is used. Need to develop.

In view of the above-mentioned problems, an object of the present invention is to perform image processing, calculate processing data, and store the processing data in advance as necessary when performing dimension measurement and appearance inspection for a fuel assembly. Compare with the data, measure the dimensions or determine the presence or absence of scratches, dirt, foreign matter, etc.
It is an object of the present invention to provide a fuel assembly inspection apparatus and an inspection method which can perform pass / fail determination of the fuel assembly by inexpensive and unattended operation.

[0010]

In order to achieve the above object, a fuel assembly inspection apparatus and an inspection method according to the present invention are provided.
It has the features described in each claim of the claims. In particular, the fuel assembly inspection apparatus according to the invention described in claim 1 as an independent claim rotates the fuel assembly, which is an object placed upright on a table, around its own axis to inspect the fuel assembly. A rotation positioning mechanism that enables the target surface to be accurately positioned in a twist-free state, and an image input unit, which will be described later, can be moved up and down over the entire height of the fuel assembly directly against the positioned inspection target surface, and also over the entire width. A fuel assembly inspection table having an image input unit moving mechanism capable of traversing movement, a lighting fixture for illuminating the inspection target portion of the fuel assembly directly facing the inspection target portion, and an imaging device for imaging the same An image input unit having equipment and stores data necessary for inspection in advance, and calculates data obtained by processing an output video from the image input unit. An image processing unit that compares various data with the stored data as needed, measures various dimensions at the inspection target site, or determines the presence or absence of scratches, dirt, foreign matter, and the like, and the fuel assembly inspection table, An inspection unit control computer that controls the input unit and the image processing unit, determines whether the fuel assembly is acceptable or unacceptable, and stores inspection data.

Further, a fuel assembly inspection method according to the invention described in claim 6 as an independent claim uses the fuel assembly inspection apparatus according to any one of claims 1 to 5 to provide a fuel assembly inspection method. Measurement and inspection items: fuel rod dimension measurement, fuel rod-water rod dimension measurement, fuel rod-
Measurement of simulated channel box-to-box dimensions, spacer width dimension measurement, expansion spring dimension measurement, squareness measurement of upper tie plate, and / or inspection of appearance inspection items such as scratches, dirt, foreign matter, etc. about,
Perform image processing, calculate the processed data, compare the data with pre-stored data as necessary, measure the above dimensions and squareness at the part to be inspected, or check for scratches, dirt, foreign matter, etc. Is determined, and whether the fuel assembly is accepted or rejected is determined.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a fuel assembly inspection apparatus and an inspection method according to the present invention will be described in detail with reference to the drawings, taking an example in which a fuel assembly of MOX new fuel is used as a subject. . As shown in FIG. 1, the fuel assembly inspection apparatus for MOX new fuel includes a fuel assembly inspection table 100, an image input unit 200, an image processing unit 300, an inspection apparatus control computer 400, and an external output device 500.

The fuel assembly inspection table 100 is provided with a rotation positioning mechanism 140 for the fuel assembly 170, and the rotation positioning mechanism 140 is mounted on the fuel assembly 17 that is the subject.
0 is held upright by the upper tie plate portion 171 and the lower tie plate portion 172 of the fuel assembly 170, and the respective grip portions of the upper tie plate portion 171 and the lower tie plate portion 172 are individually or At the same time, the fuel assembly 170 has a function of rotating and accurately positioning the fuel assembly 170 around its own axis.
The torsion around the central axis 70 can be corrected. In addition, the fuel assembly 170 can be rotated around the central axis without generating a twist around the own axis of the fuel assembly 170.

The upper tie plate section 171 and the lower tie plate section 172 are driven by separate turning motors 110 as shown in FIG. If the rotation command is issued to the upper and lower motors simultaneously, the upper tie plate unit 171 is issued.
And the lower tie plate 172 can be rotated simultaneously.

As shown in FIG. 3, only one turning motor 110 is installed in the upper or lower part or in another place, and the power is transmitted therefrom by a power transmission mechanism 120 such as a ball screw, a chain, or a belt. May be transmitted.
In this case, the clutch mechanism 125 is provided somewhere in the middle of power transmission.
The ON / OFF command for the clutch mechanism 125 can be output by the inspection device control computer 400. With these, each gripper gripping the upper tie plate portion 171 and the lower tie plate portion 172 is individually or simultaneously rotated around its own axis of the fuel assembly 170 and accurately positioned. be able to.

Further, the fuel assembly inspection table 100 includes an image input unit moving mechanism 150. The image input unit moving mechanism 150 moves the image input unit 200 mounted on the table in the horizontal and vertical directions. It has the function of moving and enabling accurate positioning. The image input unit 200 includes the image input unit moving mechanism 150.
In the vertical direction, at least the fuel assembly 17
It has a stroke that can be visualized from the top end to the bottom end of the 0 inspection range. Further, the image input unit 200
Has a stroke that can be visualized in the horizontal direction at least from the leftmost end to the rightmost end of the inspection range of the fuel assembly 170 by the image input unit moving mechanism 150.

The rotational positioning of the fuel assembly 170 and the vertical / horizontal movement positioning operation of the image input unit 200 are controlled by the inspection apparatus control computer 400 and can be performed simultaneously or individually. Thus, the image input unit 200 spreads over the entire inspection target portion of the fuel assembly 170, so that the appearance and dimensions can be inspected without preparing a plurality of the image input units 200.

The image input unit 200 is composed of a camera 210 as an image pickup device for inputting an image for imaging the inspected portion of the fuel assembly 170 and a lighting fixture 220 for illuminating the inspected portion. . On the other hand, as shown in FIG. 2, the configuration of the camera 210 is mainly a black-and-white camera 211 having a narrow-field lens for dimension measurement and a color camera 212 mainly having a wide-field lens for appearance measurement. It consists of a table.

The black-and-white camera 211 having a lens with a narrow field of view can measure the dimensions in a field of view of about 30 mm, and can measure the dimension of the fuel rod-fuel rod interval, the dimension of the fuel rod-water rod interval, and the fuel rod. Perform a dimensional measurement of the simulated channel box spacing and a squareness measurement of the upper tie plate.

The color camera 212 having a lens with a wide field of view performs a spacer width measurement, an expansion spring size measurement, a squareness measurement between the upper tie plate and the fuel rod, and an overall appearance inspection, which require a field of view of about 150 mm. Do.
As shown in FIG. 5, these cameras 211 and 212 are one color camera 213 having a zoom lens.
Can be replaced by As a result, all inspections can be performed with a minimum number of cameras.

As shown in FIGS. 4 and 5, the image input unit 200 has a transmission illumination device 221 at a position directly opposite to the camera 210 with the subject interposed therebetween. The transmitted illumination device 221 is effective when the illumination light can be photographed from the camera 210 when the illumination light is applied to the camera 210 from behind the fuel assembly 170.

The transmitted light fixture 221 is provided with the camera 2
By illuminating the fuel assembly 170 with illumination light from the back side of the fuel assembly 170, the end of the fuel rod 173 of the fuel assembly 170 and the end of the water rod 176 located at the center of the fuel assembly 170 are formed. Since the image in which the edges appear clearly is obtained from the camera 210, the fuel assembly 1 having 9 or 8 in the depth direction
The dimension measurement between the fuel rod 70 and the fuel rod 70 and between the fuel rod and the water rod can be performed with high accuracy.

As shown in FIGS. 4 and 5, the image input unit 200 has a reflection lighting device 222 for illuminating the fuel assembly 170 from the same direction as the camera 210. The reflective lighting fixture 222 irradiates the fuel assembly 170 with illumination light from the same side as the camera 210, so that the transmitted light 22, such as a fuel rod-fuel rod interval in front of the water rod 176, is used.
This is effective when measuring the dimensions of a place that cannot be photographed with the video using the illumination light and when performing an appearance inspection.

The image processing unit 300 comprises an image processing device 310 and a monitor 320. As shown in FIG. 6, a video signal from the camera 210 is input to the image processing device 310, where a digitization process, that is, an A / D conversion is performed to perform a dimension inspection and an appearance inspection, and various processes are performed. The video and image processing results are output to the monitor 320.

Data such as the results of individual image processing, inspection items, inspection locations, and the like are tabulated by the inspection device computer 400, output by the external output device 500, and displayed. In the inspection by the image processing device 310, as a dimension and squareness inspection, a dimension measurement of a fuel rod-fuel rod interval, a dimension measurement of a fuel rod-water rod interval, a fuel rod-
Simulated channel box spacing measurement, spacer width measurement, expansion spring length measurement, squareness measurement between upper tie plate and fuel rod. , There is dirt. These inspection items are performed by the following method.

As shown in FIG. 7, the dimension measurement of the fuel rod-fuel rod interval is performed as shown in FIG. 8 for the eight fuel assemblies 174 and for the seven fuel rod 173 intervals as shown in FIG. 9
The eight fuel rods 17 for the × 9 fuel assembly 175
With respect to three intervals, the transmission illumination device 221 is used for two locations from the left and right ends. Field of view 3
By moving the center of the camera 211 having a field of view of 30 mm to the center position of the fuel rod 173 interval using the camera 211 of 0 mm, 9 or 8 in the depth direction.
The fuel rods 173 having books are combined in series, and an image is obtained from the camera 211.

In the above dimension measurement, if the accuracy of photographing and image processing is high, the inspection time can be reduced by simultaneously measuring the fuel rod intervals at a plurality of locations with a camera having a lens having a wide field of view. Can also.

The image is digitized by a luminance value by the image processing device 310 and converted into an image. As shown in FIG. 9, the digitized image near the contour of the fuel rod, which is the portion to be measured, is obtained. Has the characteristic that the black and white luminance changes rapidly. In FIG. 9, pixels 901 are arranged in the X-axis direction.
, A luminance 902 in the Y-axis direction, and 9 or 8 in the depth direction.
The fuel rods 173 obtained by adding the books are shown as 173a.

An input image of the inspection point is digitally processed with luminance in the direction of the inspection point to obtain a difference between two luminance values before and after the straight line data, and a point having a large luminance gradient, which is a point larger than a predetermined value. That is, the vicinity of the end point of the fuel rod 173a is obtained. The point at which this steep luminance gradient is obtained, that is, several luminance values before and after the end point of the fuel rod 173a is obtained, the luminance gradient is calculated, and the midpoint is calculated, and the end point of the fuel rod 173a is calculated. By determining the position, the position of one pixel or less can be detected digitally (hereinafter, referred to as a sub-pixel method), and the end point of the fuel rod 173 can be obtained with high accuracy.

Further, the fuel rod 1
By obtaining a plurality of end points in the vertical direction of 73a and averaging the values, a more stable value can be obtained. The interval between the fuel rods 173 is the distance between the darkness where the brightness of the digitally processed image changes from low to dark and the brightness becomes high to dark. On the other hand, the distance between the change in brightness of the image from light to dark and the change in brightness is a known value of the outer dimensions of the fuel rod. can do.

As shown in FIG. 7, for the 8 × 8 fuel assembly 174, three intermediate portions between the seven fuel rods 173 as shown in FIG.
8 fuel rods 173 for 9 fuel assemblies 175
Since the water rod 176 has the water rod 176 at the middle position, it is difficult to employ the transmission lighting device 221, so the reflection lighting device 222 is used.

In this case, as shown in FIG. 10, the difference between the luminance values of two points before and after the linear data obtained by digitally processing the input image of the inspection point in the inspection point direction with the luminance is calculated from a predetermined value. First, a large point, that is, a point with a large luminance gradient, that is, the vicinity of the end point of the fuel rod 173a is obtained.

The luminance values at several points before and after the point where the obtained luminance gradient is large are obtained, the luminance gradients are obtained, and the end point of the fuel rod 173a is determined from the midpoint, whereby the sub-pixel is obtained in the same manner as described above. The end point of the fuel rod 173 can be obtained with high accuracy. Furthermore, a stable value can be obtained by obtaining a plurality of end points in the vertical direction of the measured object and averaging them in the same manner as the above method.

In the distance between the end points, the longer distance is the width of the fuel rod 173 itself, and the shorter distance is the distance dimension of the fuel rod 173 interval. Since there is a difference of three times or more in both values, measurement can be performed without error.

In order for the image processing device 310 to replace the distance obtained by performing image processing with the actual size, an image showing the width of the fuel rod 173 itself whose size is known can be used. The image processing apparatus 310 obtains the width of the fuel rod 173 having a known size in pixel units by image processing before performing the dimension measurement, and
From the width dimension value of 3, a constant that converts a pixel, which is a unit of the distance of the image processing device 310 obtained by image processing, that is, a pixel value, and an actual distance, that is, mm, is obtained.

The image processing device 310 uses the obtained conversion constant to measure the size of the image processing device 31 when measuring dimensions.
The distance in pixel units calculated by 0 is converted to an actual distance. This makes it possible to perform accurate measurement irrespective of mechanical play or changes in the arrangement of each device.

The dimension measurement of the fuel rod-water rod interval is performed by using the transmitted illumination device 221 and, as shown in FIG. 11, for the 8.times.8 fuel assembly 174, the distance between the seven fuel rods 173 is set. On the other hand, at the center of the third and fifth intervals from the left, as shown in FIG. 12, for the 9 × 9 fuel assembly 175, for the eight fuel rods 173, the left From the center of the third and sixth intervals
The end of the water rod 176 and the end of the fuel rod 173 are photographed by moving the camera 211 mm, and the water rod 17 is formed using the sub-pixel method described above.
By measuring the end of the fuel rod 173 and the end of the fuel rod 173 that is closest to the end, the above dimensions can be measured.

The measurement of the distance between the fuel rod and the simulated channel box was performed in the same manner as in the 9 × 9 fuel assembly 174.
The same can be applied to the fuel assembly 175. As shown in FIG. 13, when only one spacer 177 is shown in the field of view of the camera 210,
1, two upper and lower end points of the outermost fuel rod 173b sandwiching the spacer 177 are determined, and a straight line 903 connecting the two points is assumed in the image by the image processing device 310. , The straight line 903 and the spacer 17
By measuring the distance to the outermost end of No. 7, the intended dimensional measurement is performed. The end point of the outermost fuel rod 173b and the outermost part of the spacer 177 are obtained by a sub-pixel method similar to the method of measuring the distance between the fuel rods 173.

As shown in FIG. 14, when a plurality of the spacers 177 are reflected in the field of view of the camera 210, two images of the spacer A straight line 904 connecting the outermost end of the fuel rod 173 is assumed in the image by the image processing device 310, and the straight line 904 and the outermost fuel rod 173b are assumed.
The desired dimensional measurement is performed by determining the distance to the target. Also in this case, the outermost end of the spacer 177 and the end point of the outermost fuel rod 173b are obtained using the same sub-pixel method as the method of measuring the interval between the fuel rods 173.

As shown in FIG. 15, the measurement of the spacer width is performed by using the camera 212 and the transmissive lighting device 221 and the left and right ends of the spacer 177 using the sub-pixel method in the same manner as described above.

The dimensions of the expansion spring 178 are measured as shown in FIG.
As shown in FIG. 6, the image processed by the image processing device 310 is input to the image processing device 310 using the camera 212 and the reflection lighting device 222 and is digitally processed. The emphasis filter processing is performed, the end of the spring of the expansion spring 178 is obtained by image emphasis, and the distance between the uppermost and lowermost ends thereof is obtained.

As for the perpendicularity measurement between the upper tie plate 171 and the fuel rod 173, first, as shown in FIG. 17, the camera 212 and the transmission lighting fixture 221 or the reflection lighting fixture 222 are used to measure the squareness. Several points of the tie plate 171 are obtained by the sub-pixel method, and a straight line on the lower surface of the tie plate 171 is obtained from the points. Similarly, a straight line on the side surface of the fuel rod 173 is obtained by obtaining several end points on the side surface of the fuel rod 173, an intersection is calculated from the two straight lines, and an angle is obtained from the intersection and the two straight lines.

As shown in FIG. 18, inspection of the appearance of the fuel assembly 170, which is an object, for scratches, presence / absence of foreign matter, fingerprints, and dirt, which are the appearance inspection items, are performed as shown in FIG.
2 and the reflection lighting device 222. The flaw inspection is performed by using a feature that when a lighting device is applied to a flaw of a subject, the reflection of light from the flaw changes with respect to other specimens.

Since the fuel assembly 170, which is the subject, has a surface that is not parallel to the lens surface of the camera 212 like the fuel rod 173, the camera 212 needs to be used for this inspection. It is necessary to perform the luminance correction of the luminance signals of the red signal R, the green signal G, and the blue signal B, which are the video signals input from the camera. Before performing this inspection, the fuel assembly 1 without scratches
The image 70 is input from the camera 212, and the image processing device 310 stores the luminance of each point of the image as a luminance value (R + G + B) / 3.

In this case, it is not necessary to store the luminances of all points of the input image, and only the luminances of points necessary for the inspection may be stored. Using this previously stored luminance value, luminance correction is performed and a flaw inspection is performed.

In the brightness correction, the image of the fuel assembly 170 input from the camera 212 is converted to the image processing device 31.
Image processing is performed at 0, and the luminance value of each point of the inspection of the fuel assembly 170 is obtained by a value of (R + G + B) / 3, and the obtained inspection point and the luminance value stored in advance at the same position as the inspection point are used. Do it.

The luminance value P of the inspection point after the luminance correction is compared with the luminance value A of the inspection point of the fuel assembly 170, which is the subject, and the previously stored intact fuel assembly 17 of the inspection point.
It is obtained from the equation P = A−B + C using a brightness value B of 0 and a constant C. When the inspection point of the fuel assembly 170, which is the subject, is intact, the luminance value after the luminance correction becomes almost C as shown in FIG.

The flaw inspection is performed using the luminance value after the luminance correction. As described above, when light is applied to a flaw, the reflection of light changes with respect to the intact part. Therefore, the above-described luminance correction is performed on the luminance value of the video signal of the inspection point input from the camera 212. , The luminance value is determined along the inspection direction, and the difference in the luminance value between two adjacent points is determined.

When the difference between the luminance values is larger than a predetermined value, it is determined that the inspection point has a flaw. The obtained flaw is stored in the image processing device 310 with the inspection point position as position data, and the image processing result and the inspection point position are displayed on the screen of the monitor 320. Further, the image of the screen of the monitor 320 is recorded on the VTR, and the image is reproduced, so that the inspection worker can perform reconfirmation.

Inspection of foreign matter and fingerprints is obtained from the red signal R, green signal G, and blue signal B luminance signals, which are video signals of the fuel assembly 170, which is the subject, input from the camera 212. Before performing the main inspection, the image processing device 310
The image of the fuel assembly 170, which is free of foreign matter and fingerprints, is input from the camera 212 and the fuel assembly 1 is inspected.
The maximum value Rmax of the R signal of the image of the 70 inspection target area,
Minimum value Rmin, maximum value Gmax of G signal, minimum value G
min, the maximum value Bmax and the minimum value Bmin of the B signal are obtained and stored as luminance determination values.

Inspection of foreign substances and fingerprints is performed using the luminance judgment value stored in advance. The image processing device 31
0 is the R, G, B, and signal of each point in the inspection target portion for inspecting the image of the fuel assembly 170, which is the subject, input from the camera 212, and obtains the luminance of the inspection portion stored in advance. Using the judgment value, a point that satisfies the condition of R> Rmax or R <Rmin, or G> Gmax or G <Gmin, or B> Bmax or B <Bmin is obtained, and the position is stored. Next, the image processing device 3
In step 10, among the positions of the points satisfying the above condition, the connectivity adjacent in the up, down, left, and right directions is checked, and the area, which is the number of points in the connected area, is obtained for each connected area.

When the area of the connection area is larger than a predetermined value, it is determined that a foreign substance or a fingerprint exists in the connection area. For the obtained foreign matter and fingerprint, the center position of the inspection point area is stored in the image processing device 310 as position data, and the image processing result and this position are displayed on the screen of the monitor 320. Further, the video of the screen of the monitor 320 is recorded on a VTR, and the video is reproduced, so that the inspection worker can perform reconfirmation.

The photographing timing of the camera 210 and the fuel assembly inspection table 100 of the image input unit 200
, And the rotation and positioning operation of the fuel assembly 170 by the fuel assembly inspection table 100 are all controlled by the inspection apparatus control computer 400. The content inspected as described above is determined by the inspection device control computer 400, and the data thereof is stored in a storage device together with the inspection position of the fuel assembly 170 by the camera 210, and is output to the external output device. The output can be displayed by the device 500. Further, if the judgment result is not good, a function may be provided to generate an alarm and notify the inspector accordingly.

The operation flow of the MOX new fuel assembly inspection apparatus will be described with reference to the flowcharts shown in FIGS. First, the overall operation flow of the MOX new fuel assembly inspection device will be described with reference to the flowchart shown in FIG.

In step (1), the camera 210 is moved to the first inspection position of the fuel assembly 170 according to an instruction from the inspection device control computer 400. Next, in step (2), the inspection device control computer 400 performs inspection items to be inspected by the image processing device 310, for example, measurement of fuel rod-fuel rod dimensions, measurement of fuel rod-water rod dimensions, fuel Instruct the measurement of the dimension between the rod and the simulated channel box.

In step (3), the image processing device 31
0 captures an image of the fuel assembly 170 to be inspected using the camera 210. Next, step (4)
Then, the image processing apparatus 310 performs an inspection on the photographed image for an inspection item instructed by the inspection apparatus control computer 400.

In step (5), the image processing device 31
In the case of 0, after the inspection is completed, an inspection completion report is sent to the inspection apparatus control computer 400. In step (6), the inspection device control computer 400 determines whether or not all the inspections of the fuel assembly 170 have been performed.
Return to the above, move the camera 210 to the next inspection position,
The operations from step (1) to step (6) are repeated until all inspections are completed.

If it is determined in step (6) that all inspections have been performed, the flow advances to the next step (7). Since all the inspections of the fuel assembly 170 have been completed, all the inspection results are displayed on the inspection device control computer 400 or the monitor of the image processing device 310 in step (7), and the processing ends.

FIG. 21 is a flowchart showing the content of the processing in step (4) in the flowchart shown in FIG. The image processing device 310 performs digitization processing, that is, A / D conversion in step (1), in order to inspect the image captured in step (3) of the flowchart shown in FIG. In step (2), inspection of the inspection items instructed by the inspection apparatus control computer 400 in step (2) of the flowchart shown in FIG. 20 is performed.

The contents of the processing in step (2) in the flowchart shown in FIG. 21 will be described in detail with reference to the flowcharts in FIGS. The image processing device 310 includes:
In step (2) of the flowchart shown in FIG. 20, the inspection to be performed is determined in accordance with the inspection item instructed by the inspection apparatus control computer 400. In step (1), the dimension measurement between fuel rods and fuel rods Step (2) measures the dimension between the fuel rod and water rod, step (3) measures the dimension between the fuel rod and the simulated channel box, step (4) measures the spacer width dimension, step (5) measures the expansion spring dimension, Step (6) measures the squareness of the upper tie plate, step (7) inspects for flaws, step (8) detects foreign matter,
Inspect for fingerprint attachment.

FIG. 24 is a flowchart showing the contents of the process of measuring the dimension between the fuel rods in step (1) of the flowchart shown in FIG. In step (1) to step (3), the image processing device 310 may use the fuel rod 173 by a sub-pixel method.
The first end point, the second end point, and the third end point are obtained. In steps (4) and (5), the distance between the two points obtained from these three points is obtained. Is the distance between the fuel rod and fuel rod, and
Finally, the distance of image processing, that is, the fuel rod-to-fuel rod dimension obtained in pixel value units is converted to actual distance units.

FIG. 25 is a flowchart showing the details of the process of measuring the dimension between the fuel rod and the water rod in step (2) of the flowchart shown in FIG. The image processing device 310 includes steps (1) and (2)
In step (3), the end point of the water rod 176 and the end point of the fuel rod 173 are obtained by the sub-pixel method, the distance between the two points obtained from the two points is obtained in step (3), and the image processing is finally performed in step (4). The distance, ie, the dimension obtained in pixel value units, is converted to actual distance units.

The contents of the process of measuring the dimension between the fuel rod and the simulated channel box in step (3) of the flowchart shown in FIG. 22 are shown in the flowchart of FIG. 26 or FIG. The processing when only one spacer 177 is shown in the field of view of the camera 211 is shown in FIG.
Is shown in the flowchart of FIG.

In step (1) and step (2), the image processing apparatus 310 obtains two upper and lower end points of the outermost fuel rod 173b sandwiching the spacer 177 by the sub-pixel method, and connects these two points. The virtual straight line 903 is obtained. Next, in step (3), the outermost end of the spacer 177 is obtained by the sub-pixel method. In step (4), the distance between the outermost end of the spacer 177 and the virtual straight line 903 is obtained. In step (5), Finally, the image processing distance, that is, the dimension obtained in pixel value units, is converted into actual distance units.

The spacer 17 is positioned within the field of view of the camera 211.
The processing when two or more 7 are displayed is shown in the flowchart of FIG. The image processing device 310 performs step (1)
And in step (2), 2
The end points of the spacers 177 are obtained, and the virtual straight line 904 connecting these two points is obtained. Next, in step (3), the end point of the outermost fuel rod 173b is obtained by the sub-pixel method. In step (4), the distance between the end point and the virtual straight line 904 is obtained. Is converted to an actual distance unit.

The contents of the process of measuring the spacer width dimension in step (4) of the flowchart shown in FIG.
This is shown in the flowchart of FIG. The image processing device 31
0 means that the right and left end points of the spacer 177 are obtained by the sub-pixel method in the step (1), and then the step (2)
In step (3), the distance between the two points obtained from the two points is obtained. Finally, in step (3), the distance obtained in image processing, that is, the dimension obtained in pixel value units, is converted into actual distance units.

FIG. 28 is a flowchart showing the contents of the expansion spring dimension measurement processing in step (5) of the flowchart shown in FIG. In the step (1), the image processing device 310
Perform edge enhancement filter processing on the eight parts, and perform step (2).
The two points of the uppermost point and the lowermost point of the expansion spring 178 are obtained, and the distance between the two points obtained in step (3) is obtained.
In step (4), finally, the distance for image processing, ie, the dimension obtained in pixel value units, is converted into actual distance units.

FIG. 30 is a flowchart showing the details of the process of measuring the squareness between the upper tie plate and the fuel rod in step (6) of the flowchart shown in FIG. The image processing device 310 obtains several end points of the upper tie plate 171 by the sub-pixel method in step (1), and obtains a virtual straight line passing through each point in step (2).

Next, in step (3), several end points of the fuel rod 173 are obtained by the sub-pixel method, and in step (4), a virtual straight line passing through each point is obtained. Finally, in step (5), a virtual intersection of the two straight lines is determined, and an angle formed between the point and the two straight lines is determined.

FIG. 31 is a flowchart showing the contents of the flaw inspection process in step (7) of the flowchart shown in FIG. In step (1), the image processing device 310 converts the luminance values A of all the inspection points into the color camera 2.
A = (R + G + B) / from the R, G, and B signals obtained from
Then, the luminance value P obtained by performing the luminance correction of the point in step (2) is obtained from the expression P = A−B + C. Note that the value B is a luminance value of the inspection point of the fuel assembly 170 having no scratches obtained before performing the inspection, and C is a constant.

Using this luminance value P, in steps (3) to (5), a luminance value difference H between two points adjacent in the inspection direction is sequentially obtained, and a point where the value of H is larger than a predetermined value D is determined. It is determined that there is a flaw, and the position is stored. This operation is performed for all inspection points based on the determination in step (6).

FIG. 32 shows the contents of the foreign matter and fingerprint inspection processing in step (8) of the flowchart shown in FIG.
Is shown in the flowchart of FIG. The image processing device 310 includes:
In step (1), the R, G, B signals obtained from the color camera 212 at the inspection point are determined, and the R, G, B of the inspection target site determined at the inspection point of the fuel assembly 170 having no damage determined in advance. By comparing the maximum value and the minimum value of the signal with each other, a position that satisfies this condition is obtained for the entire inspection target part and stored in step (2). This operation is performed for all inspection points based on the determination in step (3).

Next, the connectivity of the positions stored in step (4) is checked, and the area of each connected region is determined.
The value of the area obtained in step (5) is compared with a predetermined value D, and a region larger than D is determined as having a foreign substance or fingerprint, and the center position of the region is stored in step (6). This operation is performed for all inspection points based on the determination in step (7).

FIG. 33 is a flowchart showing the sub-pixel method. In step (1), the image processing device 310 obtains a difference between two luminance values before and after in the inspection direction,
In step (2), a point larger than the predetermined luminance value difference is determined, and several points before and after the point determined in step (3) are determined. In step (4), the luminance values of the determined points are determined. By obtaining a luminance gradient more and obtaining the midpoint by calculation, high-precision position detection with a digital value of 1 pixel or less is performed.

[0075]

According to the present invention, in dimension and appearance inspections for a fuel assembly, image processing is performed, processing data is calculated, and if necessary, comparison with data stored in advance is performed. Inexpensive, remote operation and unmanned operation of measuring various dimensions or determining the presence or absence of scratches, dirt, foreign matter, etc., and determining whether the fuel assembly is accepted or rejected. The effect is obtained.

This reduces the heavy labor of the inspector,
It also has the effect of contributing to the safety management of nuclear power while reducing the exposure of inspectors.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of a MOX new fuel inspection device.

FIG. 2 is an explanatory view of a first embodiment of a fuel assembly rotation positioning mechanism;

FIG. 3 is an explanatory view of a second embodiment of a fuel assembly rotation positioning mechanism.

FIG. 4 is an explanatory diagram of a first embodiment of the image input unit.

FIG. 5 is an explanatory diagram of a second embodiment of the image input unit.

FIG. 6 is a configuration diagram of an image processing unit and a computer for an inspection apparatus.

FIG. 7 is an explanatory view of a method for measuring the dimension of the fuel rod-fuel rod interval of the 8 × 8 fuel assembly.

FIG. 8 is an explanatory view of a method for measuring a dimension of a fuel rod-fuel rod interval of a 9 × 9 fuel assembly.

FIG. 9 is an explanatory diagram of a change in luminance of a fuel rod at the time of a transmission lighting device.

FIG. 10 is an explanatory diagram of a change in luminance of a fuel rod at the time of a reflection lighting device.

FIG. 11 is an explanatory diagram of a method for measuring a dimension of a fuel rod-water rod interval of an 8 × 8 fuel assembly.

FIG. 12 is an explanatory view of a method for measuring a dimension of a fuel rod-water rod interval of a 9 × 9 fuel assembly.

FIG. 13 is an explanatory view of a method for measuring dimensions of a fuel rod- (single) simulation channel box.

FIG. 14 is an explanatory view of a method for measuring the dimensions of a fuel rod-simulated channel box.

FIG. 15 is an explanatory diagram of a method of measuring a dimension of a spacer width.

FIG. 16 is an explanatory diagram of a method for measuring the dimensions of an expansion spring.

FIG. 17 is an explanatory diagram of a method for measuring a squareness between an upper tie plate and a fuel rod.

FIG. 18 is an explanatory diagram of a method for confirming the presence / absence of scratches, foreign matter, fingerprints, and stains on the surface of a subject.

FIG. 19 is an explanatory diagram of an appearance inspection when a subject is intact.

FIG. 20 is an operation flow 1 of the apparatus.

FIG. 21 is an operation flow 2 of the apparatus.

FIG. 22 is an operation flow 3 of the apparatus.

FIG. 23 is an operation flow 4 of the apparatus.

FIG. 24 is an operation flow for measuring a dimension between a fuel rod and a fuel rod;

FIG. 25 is an operation flow of measuring a dimension between a fuel rod and a water rod.

FIG. 26: Operation flow of dimension measurement between fuel rod and (single) simulated channel box

FIG. 27 is an operation flow of dimension measurement between a fuel rod and a plurality of simulated channel boxes.

FIG. 28 is an operation flow of spacer width measurement.

FIG. 29: Operation flow of expansion spring dimension measurement

FIG. 30 is an operation flow for measuring the perpendicularity between the upper tie plate and the fuel rod.

FIG. 31 is an operation flow of a flaw inspection.

FIG. 32 shows an operation flow of foreign matter and fingerprint inspection.

FIG. 33 is an operation flow of the sub-pixel method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 100 ... Fuel inspection table 110 ... Turning motor 120 ... Ball screw, chain, belt, etc. 125 ... Clutch mechanism 140 ... Rotational positioning mechanism 150 ... Image input unit moving mechanism 170: Fuel assembly 171 ... Upper tie plate section 172 ... Lower tie plate Part 173: fuel rod 173a: fuel rod summed in the depth direction 173b: outermost fuel rod 174 ... 8 × 8 fuel assembly 175… 9 × 9 fuel assembly 176… water rod 177… spacer 178… expansion spring 200… image Input unit 210: Camera 211: Black-and-white camera having a lens with a narrow field of view 212 ... Color camera with a lens with a wide field of view 213: Color camera with a zoom lens 220: Lighting equipment 221: Transmission lighting equipment 222: Reflective lighting equipment 300 image processing unit 310 The image processing apparatus 320 ... monitor 400 ... inspection control calculator 500 ... external output device 901 ... pixel 902 ... luminance value 903 ... fuel rods imaginary straight line 904 ... spacer virtual line

Continuing on the front page (72) Inventor Kozo Nemoto 800, Tomita, Ohira-machi, Ohira-cho, Shimotsuga-gun, Tochigi Prefecture Within the Cooling and Refrigerating Business Dept., Hitachi, Ltd. -Within Clear Engineering Co., Ltd. (72) Inventor Kiyoshi Izumi 3-1-1, Sachimachi, Hitachi City, Ibaraki Prefecture Inside Hitachi, Ltd. Hitachi Plant (72) Inventor Hideaki Ishizaki 3-1-1, Sachimachi, Hitachi City, Ibaraki Prefecture No.1 F term in Hitachi, Ltd. Hitachi Plant (reference) 2G075 BA16 CA38 DA17 EA01 FA13

Claims (12)

[Claims] A fuel assembly, which is an object placed upright on a table, is rotated around its own axis, so that the surface to be inspected of the fuel assembly can be accurately positioned without twisting. A fuel assembly having a rotational positioning mechanism and an image input unit moving mechanism capable of vertically moving an image input unit to be described later facing the positioned surface to be inspected over the entire height of the fuel assembly and also traversing the entire width of the fuel assembly. Body inspection table, an image input unit having a lighting fixture for directly illuminating the inspection target site and illuminating the inspection target site of the fuel assembly, and an image input unit having an imaging device for imaging. Store and calculate data obtained by processing the output video from the image input unit, compare with the stored data as necessary, An image processing unit that measures various dimensions in the fuel assembly or determines the presence or absence of scratches, dirt, foreign matter, and the like, and controls the fuel assembly inspection table, image input unit, and image processing unit to control the fuel assembly. A fuel assembly inspection device, comprising: an inspection device control computer that makes a pass / fail judgment and stores inspection data. 2. The rotation positioning mechanism of the fuel assembly inspection table includes an operation mechanism that can grip an upper tie plate and a lower tie plate of the fuel assembly and rotate each gripper individually or simultaneously. The fuel assembly inspection device according to claim 1, further comprising: 3. An imaging device of the image input unit, comprising: a camera having a lens with a wide field of view capable of inputting an image of the whole view of the fuel assembly tie plate; and a minimum distance between two fuel rods of the fuel assembly. The fuel assembly inspection apparatus according to claim 1, further comprising a camera having a lens having a narrow field of view to which one image can be input. 4. An imaging device of the image input unit, wherein at least one image of an interval between two fuel rods in the fuel assembly is taken from a wide field of view in which an image of the whole view of the fuel assembly tie plate can be input. 3. The fuel assembly inspection device according to claim 1, wherein the inspection device comprises a single camera having a zoom lens that covers a narrow field of view that can be input. 5. The illumination device of the image input unit includes a transmission illumination device at a position directly opposite to a camera with the fuel assembly interposed therebetween, and a reflection illumination device for directly illuminating the fuel assembly inspection surface. The fuel assembly inspection device according to claim 3, wherein the fuel assembly inspection device has at least one kind. 6. A fuel assembly inspection apparatus according to claim 1, wherein the fuel assembly measurement and inspection items are a fuel rod dimension measurement and a fuel rod-water rod dimension measurement. Dimension measurement between fuel rod and simulated channel box, spacer width measurement, expansion spring size measurement, squareness measurement of upper tie plate, and inspection of appearance inspection items such as scratches, dirt, foreign matter adhesion, etc. Image processing is performed for all or any of them, the processed data is calculated, and if necessary, the data is compared with data stored in advance to measure the above dimensions and squareness at the inspection target site, or to determine whether scratches, dirt, or foreign matter is present. A method for inspecting a fuel assembly, comprising determining whether or not the fuel assembly is attached and determining whether the fuel assembly is accepted or rejected. 7. The transmitted light illumination is performed by moving the center of the camera to the center between two fuel rods by using the camera having a lens with a narrow field of view according to claim 3. The image between the two fuel rods is digitized by the image processing unit using a luminance value, and the end point of the fuel rod is determined from a rapid change in the luminance value to determine the distance between the end points. The fuel assembly inspection method according to claim 6, wherein: 8. The dimension measurement between the fuel rod and the water rod uses a camera having a lens with a narrow visual field according to claim 3, and the center of the camera is located at a position of an end of the water rod between the fuel rods. Moving, the image using the transmitted illumination is digitized with a luminance value by the image processing unit, the end point of the fuel rod and the end point of the water rod are determined from a sudden change in the luminance value, and the distance between the end points is determined. 7. The fuel assembly inspection method according to claim 6, wherein: 9. The fuel assembly inspection method according to claim 6, wherein the dimension measurement method uses a sub-pixel method. 10. The dimension measuring method according to claim 6, wherein a pixel and a dimension are converted by using an image of a known dimension at the time of photographing a dimension at the same distance as the dimension measuring object. The fuel assembly inspection method according to any one of the above. 11. The inspection of the fuel assembly, which is an inspection object input from a camera having a lens with a wide field of view, using luminance data of an inspection point of the fuel assembly that is intact stored in advance. 7. The method according to claim 6, wherein the luminance of the image of the point is corrected, and the difference between the luminance values of two adjacent inspection points is determined. When the difference is larger than a predetermined value, it is determined that there is a flaw. The fuel assembly inspection method described in the above. 12. The inspection for dirt and foreign matter uses a red signal R, a green signal G, and a blue signal B, which are input signals of a camera having a lens having a wide field of view, and uses the previously stored dirt and foreign matter-free fuel assembly. The maximum brightness value and the minimum brightness value at each point of the R, G, and B3 signals, which are video signals of the body inspection area, are determined, and the brightness at the inspection point of the fuel assembly to be inspected is compared. The position of the inspection point larger than the maximum luminance value or smaller than the minimum luminance value is obtained, the number of positions of the area where the positions are connected is converted into the actual area, and the presence or absence of dirt and foreign matter is determined based on the magnitude of the actual area. 7. The fuel assembly inspection method according to claim 6, wherein the determination is made.