JP2010210464A - Method of surveying fuel assembly - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of surveying fuel assemblies capable of simplifying the structure of a fuel assembly survey instrument and also further improving the measurement accuracy for intervals between fuel rods. <P>SOLUTION: Each of the fuel rods 27 laid out on one lateral side of an MOX fuel assembly 26 is irradiated downward obliquely with linear light from an illuminator 11. The light applied obliquely impinges on the surface of each of the fuel rods and is reflected. An image capturing apparatus 10 launches the light reflected from each of the fuel rods to photograph it. Image processing is given to picture information on each of the fuel rods photographed by the image capturing apparatus 10, and the obtained image information is indicated on a display. On the basis of the indicated image information, the dimensions of mutual intervals formed between the fuel rods are measured. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a fuel assembly inspection method, and more particularly, to a fuel assembly suitable for application to the measurement of the distance between fuel rods of a fuel assembly including a water rod used in a boiling water reactor. Concerning body inspection methods.

After manufacturing a new fuel assembly containing UO ₂ , it is determined whether the interval between the fuel rods of the fuel assembly is equal to or larger than a set dimension by using a test jig or the like by manual inspection. We are inspecting.

  However, in a MOX fuel assembly manufactured using MOX (mixed oxide) fuel material as a nuclear fuel material, even if it is a new fuel assembly, workers may be exposed to radiation from the MOX fuel material. . In order to reduce the exposure and burden on workers in the inspection of the fuel rod interval after the manufacture of the MOX fuel assembly, a fuel assembly inspection device has been proposed (for example, Japanese Patent Laid-Open No. 2000-9880 and Japanese Patent Laid-Open No. 11-2009). No. 337679).

  The fuel assembly inspection apparatus described in Japanese Patent Laid-Open No. 2000-9880 and Japanese Patent Laid-Open No. 11-337679, when measuring the distance between the fuel rods, illuminates from the back of the fuel assembly and transmits between the fuel rods. The incident light is incident on an imaging device installed in front of the fuel assembly. This imaging apparatus performs image processing based on incident light and creates image information indicating the interval between fuel rods. Using the obtained image information, the dimension of the minimum fuel rod interval is measured, and it is determined whether or not the fuel rod interval is equal to or greater than a specified dimension.

  In the fuel assembly inspection apparatus described in Japanese Patent Application Laid-Open No. 2000-9880, an illumination device is also disposed on the front surface of the fuel assembly in order to measure the interval between the fuel rods disposed on the front surface of the water rod. . The light irradiated from the illuminating device is reflected by a water rod, and the dimension of the minimum fuel rod interval is measured using image information obtained by making the reflected light enter the imaging device.

  In measuring the dimension of the gap formed between the fuel rods of the fuel assembly, it is possible to irradiate the laser beam obliquely from the laser light source toward the fuel rod. -72285. In these fuel rod interval measurement methods, the reflected light from the fuel rods is captured by a camera to grasp the arranged fuel rods, and the fuel rod intervals are measured.

JP 2000-9880 A JP-A-11-337679 JP-A-5-34490 JP-A-7-72285

  In the fuel assembly inspection apparatus described in Japanese Patent Application Laid-Open No. 2000-9880, in a fuel assembly having a large diameter water rod, the size of the interval between fuel rods positioned in front of the large diameter water rod, and the large diameter water rod Different illumination devices are provided in case of measuring the dimension of the spacing of the fuel rod arrays which are not obstructed by each. That is, an illumination device for transmitted light and an illumination device for reflected light are installed.

  As described in JP-A-5-34490 and JP-A-7-72285, when a fuel rod that forms a curved surface is irradiated with a laser beam having a high degree of straightness, reflection on the outer surface of the fuel rod Light is dispersed. For this reason, the reflected light of the laser beam cannot maintain uniformity, and it is difficult to capture the reflected light near the edge with a camera. Laser light is highly straight, and laser light reflected from the outer surface of the fuel rod forming a curved surface does not reflect to the camera side. Therefore, it is impossible to accurately measure the distance between the fuel rods.

  It is an object of the present invention to provide a fuel assembly inspection method that can simplify the structure of a fuel assembly inspection device and can further improve the measurement accuracy of the distance between fuel rods. is there.

  A feature of the present invention that achieves the above-described object is that the line-shaped light generated by the lighting device is irradiated obliquely downward from one side of the fuel assembly to each of the fuel rods. The light reflected from the fuel rods is photographed by the imaging device, and the minimum distance between the fuel rods is obtained based on the image information of each fuel rod photographed by the imaging device.

  Since the line-shaped light generated by the illumination device is irradiated obliquely downward from one side of the fuel assembly to each of the fuel rods, images of each fuel rod taken by the imaging device Based on the information, an image of each fuel rod in a plurality of rows can be identified from the imaging device. For this reason, the dimension of the space | interval between fuel rods can be measured accurately.

  In addition, by irradiating the line-shaped light generated by one illumination device obliquely from one side of the fuel assembly, the first fuel rods positioned on the front surface of the water rod and blocked by the water rod are first. The respective dimensions of the gap and the second gap between the fuel rods not blocked by the water rod can be measured. For this reason, in the present embodiment, it is not necessary to use separate illumination devices when measuring the respective sizes of the first gap and the second gap, so that the structure of the fuel assembly inspection apparatus can be simplified. .

  According to the present invention, the structure of the fuel assembly inspection apparatus can be simplified, and the measurement accuracy of the distance between the fuel rods can be further improved.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a configuration diagram of a fuel assembly inspection device used in a fuel assembly inspection method according to embodiment 1, which is a preferred embodiment of the present invention. It is II-II sectional drawing of FIG. It is a block diagram of the moving apparatus shown in FIG. It is explanatory drawing which shows the state which is implementing the test | inspection of a fuel assembly in Example 1. FIG. It is explanatory drawing which shows the example of a display of the image information of the adjacent fuel rod obtained in Example 1. FIG. It is a block diagram of the fuel assembly inspection apparatus used for the inspection method of the fuel assembly of Example 2 which is another Example of this invention. It is VII-VII sectional drawing of FIG.

  Examples of the present invention will be described below.

  A method for inspecting a fuel assembly according to embodiment 1 which is a preferred embodiment of the present invention will be described below. First, a fuel assembly inspection apparatus used in the fuel assembly inspection method of the present embodiment will be described with reference to FIGS. 1, 2, and 3.

  The fuel assembly inspection apparatus 1 includes an elevating device 5, a moving device 9, an imaging device (camera) 10, and an illumination device 11. A mast 3 provided with a pair of guide rails 4 is vertically attached to the base 2. The guide rail 4 extends in the vertical direction. A fuel assembly receiving member 15 is provided on the upper surface of the base 2 at a position away from the mast 3. The elevating device 5 is attached to the mast 3 so as to be movable in the vertical direction (Z direction). The lifting device 5 moves up and down along a guide rail 4 provided on the mast 3. A rail holding member 7 having a pair of guide rails 8 provided on the upper surface is installed on the upper surface of the lifting device 5. The guide rail 8 is disposed in the horizontal direction and extends in a direction perpendicular to the guide rail 4 (Y direction).

  The moving device 9 is installed on the upper surface of the rail holding member 7. As shown in FIG. 3, the moving device 9 has a motor 17 and a screw rod 20. The motor 17 is installed on the rail holding member 7, and the screw rod 20 is also attached to the rail holding member 7 by bearings (for example, bearings) 21A and 21B that hold both ends. A gear 18 attached to the rotating shaft of the motor 17 meshes with a gear 19 attached to the screw rod 20. A moving body 16 is movably installed on the guide rail 8. The moving body 16 is provided with an imaging device 10 and a lighting device 11 that generates line-shaped light (for example, halogen light and LED). The illuminating device 11 is attached to the moving body 16 so as to irradiate the line-shaped light obliquely downward. The imaging device 10 is connected to the image processing device 23, and the image processing device 23 is connected to the display device 21 (see FIG. 4).

  A fuel assembly gripping device 6 is provided in the fuel assembly inspection device 1. The fuel assembly gripping device 6 includes a pair of support members 12A and 12B, cylinder devices 13A and 13B, and pressing plates (pressing members) 14A and 14B. The pressing plates 14A and 14B extend in the vertical direction. The pair of support members 12 </ b> A and 12 </ b> B are attached to the lifting device 5 in a state of being separated from each other in the direction in which the guide rail 8 extends (Y direction). These support members extend away from the mast 3. The cylinder device 13A is installed on the upper surface of the support member 12A. The pressing plate 14A is attached to a piston rod 22A provided in the cylinder device 13A. The cylinder device 13B is installed on the upper surface of the support member 12B. The pressing plate 14B is attached to a piston rod 22B provided in the cylinder device 13B.

  The MOX fuel assembly 26 inspected by the fuel assembly inspection apparatus 1 includes a lower tie plate (not shown), an upper tie plate (not shown), a plurality of fuel rods 27 arranged in 8 rows and 8 columns, water It has a rod 28 and a fuel spacer 29 (see FIG. 2). The lower tie plate supports the lower ends of these fuel rods 27, and the upper tie plate supports the upper ends of these fuel rods 27. The water rod 28 is disposed between the fuel rods 27, and the lower end portion and the upper end portion of the water rod 28 are also supported by the lower tie plate and the upper tie plate. The cross-sectional area of the water rod 28 is large enough to occupy a region where the four fuel rods 27 can be arranged. The plurality of fuel spacers 29 arranged in the axial direction of the fuel assembly 26 bundles the fuel rods 27 and keeps the distance between the fuel rods 27 at a set size.

  The fuel assembly inspection method of the present embodiment using the fuel assembly inspection apparatus 1 will be specifically described below. This inspection method is applied to the manufactured MOX fuel assembly 26. The elevating device 5 is raised along the guide rail 3 until the imaging device 10 reaches a position for inspecting the dimension of the gap formed between the fuel rods 27. When the imaging device 10 reaches a predetermined height, the lifting of the lifting device 5 is stopped. The MOX fuel assembly 26 to be inspected is placed vertically on the base 2. The MOX fuel assembly 26 is gripped by the fuel assembly gripping device 6. That is, by operating the cylinder devices 13A and 13B, the pressing plates 14A and 14B are moved to both sides of the MOX fuel assembly 26 placed on the base 2, that is, both sides of the two fuel spacers 29 arranged in the axial direction. Touch the surface. The MOX fuel assembly 26 is sandwiched and held between the pressing plates 14A and 14B. The distortion of the MOX fuel assembly 26 is corrected by sandwiching the MOX fuel assembly 26 between the pressing plates 14A and 14B.

  The imaging device 10 and the illumination device 11 are positioned at the extreme end position on one side surface of the MOX fuel assembly 26. This positioning is performed by the moving device 9. The motor 17 is driven. The rotational force of the motor 17 is transmitted to the screw rod 20 through the gears 18 and 19, and the screw rod 20 rotates. The moving body 16 meshing with the screw formed on the screw rod 20 moves in the Y direction by the rotation of the screw rod 20. By the movement of the moving body 16, the imaging device 10 and the illumination device 11 are positioned at the extreme end position described above.

  After the positioning is completed, the MOX fuel assembly 26 is irradiated with line-shaped light generated by the illumination device 11. Since the illumination device 11 is inclined as described above, the line-shaped light emitted from the illumination device 11 is applied to each fuel rod 27 of the MOX fuel assembly 26 obliquely from above to below. The light reflected from each fuel rod 27 by the line-shaped light irradiation is photographed by the imaging device 10. When the imaging device 10 captures the reflected light from each fuel rod 27, the first row of fuel rods 27 </ b> A, the second row of fuel rods 27 </ b> B, and the third row of fuel rods 27, i.e., from the imaging device 10. The illumination device 11 is installed at an angle such that the reflected lights of the fuel rods 27C and the fuel rods 27D in the fourth row do not overlap each other, and linear light is irradiated obliquely at the angles.

  In the fuel rod arrangement of the MOX fuel assembly 26, the direction in which the imaging device 10 moves, that is, the fuel rod arrangement parallel to the Y direction is referred to as a row for the sake of convenience and is orthogonal to the moving direction of the imaging device 10. For convenience, the fuel rod arrangement parallel to the direction, that is, the X direction is referred to as a row. The line-shaped light emitted from the illumination device 11 is irradiated to the fuel rods 27 in a plurality of rows.

  The line-shaped light irradiated obliquely is reflected by the curved surface and edge of the fuel rod 27 and enters the imaging device 11. Images of the fuel rods 27 photographed by the imaging device 11 when the line-shaped light is irradiated are input to the image processing device 23. The image processing device 23 performs image processing using the captured video information of each fuel rod 27. Image information of each fuel rod 27 obtained by this image processing is output from the image processing device 23 to the display device 21 and displayed on the display device 21 (see FIG. 5). In the image displayed on the display device 21, as shown in FIG. 5, the portions of the fuel rods 27 become white, the gaps between the fuel rods 27, and the portions of the fuel rods 27 that are not exposed to line light. Turns black.

  Let C be the center position in the horizontal direction of the screen 23 of the display device 21 (see FIG. 5). In the screen 23, the leftmost region from the center position C in the image of the fuel rod displayed on the screen 23 is the left edge portion X1. In the screen 23, the portion of the fuel rod image displayed on the screen 23 closest to the position C in the region on the right side from the center position C is defined as the right edge portion X 2. The width of the edge portion X1 and the edge portion X2 is the fuel rod minimum interval dimension in the arrangement of the fuel rods 27 arranged from the imaging device 10 to the fourth row.

  The edge portions X1 and X2 are positions where the luminance is 0 at the position closest to the position C in the image displayed on the screen 23. The brightness of the image with respect to the interval formed between the fuel rods 27 is zero. In the displayed image, the brightness of the white portion (the portion of the fuel rod 27) is greater than zero. The size of the space formed between the adjacent fuel rods 27 is calculated using the size of one pixel measured in advance. That is, the dimension of the interval is calculated by multiplying the number of pixels (X2-X1) between the edge part X1 and the edge part X2 by the dimension of the one pixel. The obtained dimension is the minimum fuel rod interval between the fuel rods 27 at the position photographed by the imaging device 10 (the position at the extreme end of one side of the MOX fuel assembly 26).

  After the measurement of the fuel rod gap dimension at the extreme end position on one side of the MOX fuel assembly 26 is completed, the moving body 16 is moved in the Y direction by the moving device 9. The moving body 16 is moved by moving the imaging device 10 and the illumination device 11 toward the central portion of one side surface of the MOX fuel assembly 26. Each fuel rod 27 is irradiated obliquely with line-shaped light from the illumination device 11 at different positions in the Y direction on one side surface of the MOX fuel assembly 26. The imaging device 10 enters the reflected light from each fuel rod 27 and images each fuel rod 27. As described above, image processing is performed on the video information input by the image processing device 23, and the obtained image information is displayed on the display device 21. The minimum distance between fuel rods at the position where the imaging device 10 has taken a picture is obtained. As described above, at a certain position in the axial direction of the MOX fuel assembly 26, the measurement of the fuel rod minimum gap dimension is sequentially performed on one side of the MOX fuel assembly 26 from one end of the fuel rod array to the other end. Done.

  After the measurement of the fuel rod minimum gap dimension at that position in the axial direction is completed, the elevating device 5 is raised to another position in the axial direction of the MOX fuel assembly 26. Then, measurement of the fuel rod minimum gap dimension on one side surface of the MOX fuel assembly 26 is performed at another position in the axial direction. When the measurement of the minimum fuel rod gap dimension on one side of the MOX fuel assembly 26 is completed, the MOX fuel assembly 26 is rotated by 90 ° on the base 15 as necessary, and the minimum fuel rod spacing on the other side is determined. Measurement of dimensions is carried out in the same way.

  In this embodiment, the illumination device 11 that generates line-shaped light is used to irradiate the line-shaped light obliquely with respect to each fuel rod for measuring the distance dimension. The positions of the first row of fuel rods 27, the second row of fuel rods 27 adjacent to the fuel rod 27, the third row of fuel rods 27, and the fourth row of fuel rods 27 are Each fuel rod 27 can be identified by photographing with the imaging device 10. This is because (1) the fuel rods 27 in each row photographed by the imaging device 10 based on the reflected light from the fuel rods 27 in each row of the line-shaped light obliquely irradiated to the fuel rods 27 in each row. And (2) the reflected light from the fuel rods 27 having the curved surface of each row can be captured uniformly by the imaging device 10 by irradiating light with a highly diffusive line shape. And (3) By irradiating the line-shaped light obliquely, the reflected light around the edges of the fuel rods 27 in each row can be efficiently incident on the imaging device 10.

  For this reason, in this embodiment, the fuel rod minimum gap dimension of the MOX fuel assembly 26 can be accurately measured.

  Since the irradiation device 11 that irradiates the line-shaped light obliquely is provided, the structure of the fuel assembly inspection device 1 can be simplified. By providing such an irradiating device 11, the line-shaped light irradiated from the illuminating device 11 is used to arrange the fuel rods in a plurality of rows that are located in front of the water rod 28 and are blocked by the water rod 28. The space formed between the fuel rods (the space formed between the fuel rods in the fuel rod array of part A shown in FIG. 2), and the fuel rods in the fuel rod array in a plurality of rows not blocked by the water rod 28 Each dimension of the space | interval formed between each (The space | interval formed between the fuel rods in the fuel rod arrangement | sequence of the B section shown in FIG. 2) can be measured. Thus, in this embodiment, it is not necessary to use a separate lighting device when measuring the dimension of the space formed between the fuel rods in the fuel rod arrangements of the A part and the B part. The structure of the assembly inspection apparatus 1 can be simplified.

  In this embodiment, when the fuel rods 27 are photographed by the imaging device 10, both side surfaces of the two fuel spacers 29 arranged in the axial direction, which are located on the opposite sides of 180 °, are sandwiched between the pressing plates 14A and 14B. Therefore, the distortion of the MOX fuel assembly 26 can be corrected. For this reason, the dimension of the space formed between the fuel rods 27 can be obtained with high accuracy.

  A method for inspecting a fuel assembly according to embodiment 2, which is another embodiment of the present invention, will be described below. First, a fuel assembly inspection apparatus used in the fuel assembly inspection method of this embodiment will be described with reference to FIG. The fuel assembly inspection device 1A used in the present embodiment has a configuration in which a rail holding member 7A, a moving device 9A, an imaging device (camera) 10A, and an illumination device 11A are added to the fuel assembly inspection device 1 used in the first embodiment. Have. The rail holding member 7A is attached to the support members 12A and 12B at a position away from the rail holding member 7. The pair of rails 8 </ b> A are installed on the upper surface of the rail holding member 7 </ b> A so as to be parallel to the rails 8. A moving device 9A having the same configuration as the moving device 9 is also installed on the upper surface of the rail holding member 7A. The moving body 16A is movably installed on the rail 8A and meshes with the screw rod 20 of the moving device 9A. The imaging device 10A and the illumination device 11A are provided on the moving body 16A. The illumination device 11 </ b> A is inclined so as to irradiate line-shaped light obliquely from above to below as in the illumination device 11.

  The MOX fuel assembly 26 to be inspected placed on the base 15 is disposed between the rail holding member 7 and the rail holding member 7A. The MOX fuel assembly 26 is gripped by the fuel assembly gripping device 6. The reflected light from each fuel rod 27 of the line-shaped light irradiated obliquely downward from the illumination device 11 is photographed by the imaging device 10 and the fuel rod minimum gap dimension is measured based on this image. The same is done.

  The illuminating device 11A irradiates the other side surface (side surface II) 180 ° opposite to the one side surface (side surface I) photographed by the imaging device 10 of the MOX fuel assembly 26 (FIG. 5). 7). This line-shaped light is irradiated obliquely downward toward each fuel rod 27 on the other side surface side. The imaging device 10 </ b> A receives reflected light from the fuel rods 27 on the other side surface and images these fuel rods 27. The video information captured by the imaging device 10A is input to the image processing device 23 in the same manner as the video information captured by the imaging device 10. In the present embodiment, the image processing device 23 generates the first image information of each fuel rod 27 based on the video information of each fuel rod 27 on the side surface I photographed by the imaging device 10, and photographed by the imaging device 10A. Based on the video information of each fuel rod 27 on the side II side, second image information of these fuel rods is generated. The first and second image information is displayed on the display device 21.

  In this embodiment, the imaging device 10 and the illumination device 11 can be used to measure the gaps between the fuel rods in the fuel rod arrangements of the A part and the B part on the side surface I. Using the lighting device 11A, in the side surface II, the gaps between the fuel rods in the fuel rod arrangements of the A part and the B part can be measured.

  In this embodiment, the effects produced in the first embodiment, that is, the simplification of the structure of the fuel assembly inspection apparatus and the further improvement in the measurement accuracy of the fuel rod interval can be obtained. Further, in the present embodiment, since the light beams 11 and 11A can be simultaneously irradiated on the side surfaces I and II by the illumination devices 11 and 11A, the fuel rods 27 arranged on both side surfaces are imaged. Images can be taken simultaneously using the apparatuses 10 and 10A. For this reason, the measurement of the interval between the fuel rods of the MOX fuel assembly 26 can be completed in a short time.

  Examples 1 and 2 can also be applied to the measurement of the fuel rod spacing of a fuel assembly that contains uranium but does not contain plutonium instead of the MOX fuel assembly 26.

  The present invention can be applied to the measurement of the distance between fuel rods of a fuel assembly loaded in a nuclear reactor.

  DESCRIPTION OF SYMBOLS 1,1A ... Fuel assembly inspection apparatus, 3 ... Mast, 5 ... Elevating device, 6 ... Fuel assembly holding device, 9, 9A ... Moving device, 10, 10A ... Imaging device, 11, 11A ... Illumination device, 12A, 12B: support member, 13A, 13B ... cylinder device, 14A, 14B ... pressing plate, 16 ... moving body, 17 ... motor, 20 ... screw rod, 26 ... MOX fuel assembly, 27 ... fuel rod, 28 ... water rod, 29 ... Fuel spacer.

Claims (3)

In a fuel assembly inspection method for determining a dimension of a space between the fuel rods of a fuel assembly including a fuel rod and a water rod having an outer diameter larger than an outer diameter of the fuel rod,
Each of the fuel rods is irradiated with the line-shaped light generated by the illumination device obliquely downward from one side surface of the fuel assembly to each of the fuel rods existing on the one side surface. A fuel assembly inspection characterized in that light reflected from an image is photographed by an imaging device, and a dimension of an interval between the fuel rods is obtained based on video information of each of the fuel rods photographed by the imaging device Method.   From the other side of the fuel assembly that is 180 ° opposite to the one side, the line-shaped light generated by another lighting device is applied to each of the other fuel rods existing on the other side. Then, the image of each of the other fuel rods photographed by the other imaging device, which is irradiated obliquely downward and photographed by the other imaging device, is reflected from each of the other fuel rods. The method for inspecting a fuel assembly according to claim 1, wherein a dimension of an interval between the other fuel rods is obtained based on the information.   The two fuel spacers provided on the fuel assembly are sandwiched between a pair of pressing members positioned in a direction perpendicular to the irradiation direction of the line-shaped light when photographing the fuel rod. 3. A method for inspecting a fuel assembly according to 2.

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