RU2334944C2 - Device for monitoring of spacer grids - Google Patents

Abstract

FIELD: physics.

SUBSTANCE: device for monitoring of spacer grids contains the following elements that are serially installed on optical axis: source of coherent radiation, shaper of structural lighting, device of spacer grid positioning and photo-receiving module, which includes lens and photo-receiving chamber with matrix photodetector, which is connected with unit of control and information processing, the control outlet of which is connected to positioning device. Shaper of structural lighting is arranged in the form of diffraction optical element on the basis of phase or/and amplitude microstructure on transparent wafer, which contains non-transparent area installed in the center of diffraction optical element, working field that shapes the system of light strips on the surface of monitored fragment of spacer grid, and alignment field that shapes two light rings of the same diameter as the working field, for alignment of photo-receiving module.

EFFECT: simplification of device design with simultaneous expansion of functional resources and increase of its fast-action.

6 dwg

Description

The invention relates to the field of measuring technology and can be used in the nuclear industry in the manufacture of spacer grids of fuel assemblies.

The distance grid (DR) is a set of thin-walled cells framed on the outside with a rim (F. G. Reshetnikov, Yu. K. Bibilashvili, I. S. Golovnin and others. Design, production and operation of fuel elements of power reactors. Book 1. M .: Energoatomizdat, 1995). In the manufacture of fuel assemblies, fuel elements (fuel elements) are inserted into the cells. A number of DRs located along the height of the fuel assemblies ensures its rigidity and the necessary distance between the fuel elements. In the manufacture of DRs, the following parameters are controlled: diameter of the circle inscribed in the cell; the diameter of the circle inscribed in the hole under the channel; positional deviations of the centers of the inscribed circles in the cell and in the hole for the channel; turnkey size; belonging of the coordinates of the outer surface of the DR rim to the tolerance field; the presence / absence of a cell at the location of the hole for the channel (normal design is the absence of a cell).

A device for controlling the openings of parts is known (see patent RU No. 2245516 C2, class G01B 11/30), containing a light source, a collimator, a shaper of an optical ring mark in the form of a diffraction plate, and a projector of a ring mark in the form of a conical mirrors and a matrix photodetector connected to the signal processing unit, as well as a unit for moving the part along the axis.

This device can be used to control the DR, however, it is necessary to introduce an additional two-coordinate table in its composition for moving the DR along two coordinates in a plane perpendicular to the optical axis, while the device has two significant drawbacks.

Firstly, low performance due to the mechanical movement of the DR along the optical axis, which is necessary when controlling its height parameters (over several sections).

Secondly, the low accuracy of control, due to the additional error in the positioning of the DR when monitoring its parameters in different sections along the height.

The closest in technical essence to the claimed device (prototype) is a device for non-contact control of the geometric parameters of the DR of nuclear reactors (see O. I. Bityutsky, V. V. Vertoprakhov, A. A. Gushchina, etc. Three-dimensional non-contact control of geometrical parameters of distance gratings of nuclear reactors // Avtometriya, 2003, Volume 39, No. 5), containing a coherent radiation source sequentially located on the optical axis, a structural illumination shaper, a DR positioning device and a photodetector module Connected to the control unit and information processing. The above features of the prototype coincide with the essential features of the claimed invention.

The prototype structural illumination shaper consists of a Dammann array node, splitting the laser beam into a 12 × 13 matrix of diffraction orders, and a prism separating the diffracted rays in three directions (at 120 ° to each other). The formed three matrices of light beams illuminate at an angle of 30 ° the surface of three beetles inside the DR cell. The DR cells are changed at the control position using the precision positioning (moving) device of the DR along XY coordinates, and when controlling the openings for the channel and the “turnkey” size (lattice rim), the positioning device rotates the DR. The photodetector module consists of three identical lenses and three CCD cameras, which provide registration of the light distribution on the surfaces of the DR elements. Information from the CCD cameras is processed in the control unit and information processing, which also controls the positioning device DR.

The known device allows you to control the following parameters DR:

- diameters of inscribed circles of cells;

- diameters of the inscribed circles of the holes for the channels;

- the distance between adjacent cells (the distance between the centers of the inscribed circles);

- shifts of the centers of the inscribed circles for the cells relative to the parameters of the drawing DR;

- "turnkey" dimensions, characterizing the overall dimensions of the DR.

The main disadvantages of the known device are, firstly, its complex design, due to the presence of three image registration channels and a positioning device with a DR rotation mechanism at the measuring position.

Secondly, this device is intended only to control a number of DRs having a hexagonal shape and cells with three protrusions (beak), and cannot be used to control DRs of another shape, for example, square.

Thirdly, the device has low productivity due to the time required to ensure the rotation of the DR at the measuring position when monitoring the holes for the channel and the rim of the DR.

The aim of the present invention is to remedy these disadvantages and achieve the following technical result: simplifying the design of the device while expanding the functionality and increasing its speed.

The specified technical result during the implementation of the invention is achieved by the fact that the claimed device contains a coherent radiation source, a shaper of structural lighting (PSO), a positioning device DR and a photodetector located in series on the optical axis. FSO is made in the form of a diffractive optical element (DOE) based on a phase and / or amplitude microstructure on a transparent substrate. DOE contains an opaque region located in the center of the element, a working field that forms a system of light strips on the surface of the controlled fragment of DR, and an adjustment field that forms two light rings of the same diameter as the working field for aligning the photodetector module. The photodetector module includes a lens and a camera with a matrix photodetector. In addition, the inventive device contains a control unit and information processing, the input of which is connected to a photodetector camera, and the output to a positioning device.

Distinctive features of the prototype are the performance of the FSO in the form of DOEs based on a phase or / and amplitude microstructure on a transparent substrate containing an opaque region located in the center of the DOE, a working field that forms a system of light strips on the surface of a controlled fragment of DR, and an adjustment field that forms two light rings of the same diameter as the working field to align the photodetector module.

The invention is illustrated figure 1-6, where figure 1 presents a structural diagram of the inventive device; figure 2 - design DR; figure 3 - device shaper structural lighting; figure 4 shows a diagram of the image formation of the alignment rings; figure 5 explains the principle of image processing from a photodetector camera; figure 6 shows a view of the image from the photodetector camera obtained from the cell DR.

The inventive device (figure 1) consists of sequentially located along the optical axis of a coherent radiation source 1, FSO 2 in the form of DOE focusing the radiation of source 1 into a system of light strips 3 on the surface of a controlled fragment 4 of DR 5, a positioning device 6 of controlled DR 5, a photodetector module 7, consisting of a lens 8 and a photodetector camera 9 with an array photodetector 10. The output of the photodetector camera 9 is connected to the video input of the control and information processing unit 11, the control output of which is connected to the device Twomey ranking 6 controlled HLR 5.

The design of the DR of one type (hex) is shown in figure 2. The control elements of the DR are cells 12 (dimensions D _ce , L), openings for the channel 13 (size D _ch ) and rim 14 (size B).

Shaper of structural lighting 2 - DOE - is made in the form of a phase and / or amplitude microstructure on a transparent substrate. The DOE device is shown in Fig.3. The opaque region 16, the working field 17 and the adjustment field 18 are located on the substrate 15. The opaque region 16 in the center of the DOE does not pass direct radiation from the coherent radiation source 1 into the lens 8 and reduces the angular aperture of the working field 17, as a result of which the surface of the element 4 being monitored is illuminated radiation in which there are no gliding rays. The working field 17 creates a wave front, which at a given distance is transformed into a set of light strips 3. The alignment field 18 forms two light rings 19 (Fig. 4) of the same diameter that forms the working field 17, but in this case, the rays 20 do not intersect the optical axis. If there are DR elements in the control zone, these rays do not fall into the aperture of the projection lens 8, and the alignment rings are absent in the image from camera 9. When there is no DR, only rays from the adjustment field 18 enter the aperture of lens 8. According to the image from the photodetector, there are 9 light rings 19 aligns the photodetector module 7 with respect to the rest of the optical system. With proper adjustment, the image will look like two concentric circles 21.

The inventive device (figure 1) works as follows. A parallel beam of light from a coherent radiation source 1 illuminates the structural illumination shaper - DOE 2, which forms a set of light rings (bands) on the controlled cell 4 (or other DR element) 3. The illuminated surface of the controlled fragment of the DR is projected by lens 8 onto the photodetector 10 of camera 9 The registered image is transmitted to the control and information processing unit 11, where depending on the element installed on the measuring position (cell, hole for the channel or rim of the DR), I process the image of the corresponding element of DR 5 and its geometric parameters are calculated. Further, the information control and processing unit 11 generates control signals for the movement of the controlled DR 5 to the two-coordinate positioning device 6 for positioning the next element of the DR 5 at the measuring position. Thus, the whole DR is sequentially measured.

The principle of image processing of various elements of the DR is illustrated in Fig.5. When controlling the openings for the channel 13 and the rim of the grating 14, the light strips 3 on the surface of the DR element in the image from the photodetector camera 9 look like a set of arcs 22, which differ in length and curvature depending on the type of the DR fragment being monitored. When monitoring cells 12 DR on the image will be observed several (by the number of beetles that fix the fuel elements) sets of arcs (Fig.6), located symmetrically relative to the center of the image at certain angles relative to each other.

Image analysis is performed in the polar coordinate system with the center O (Fig.6) corresponding to the position of the optical axis, which is determined during the alignment of the system using radiation from the alignment field 18 DOE. Images of arcs are radially scanned from the center O with a certain step along the angle Δφ. In the radial direction, the intensity distribution I (R) is a sequence of peaks. The first peak of intensity corresponds to the light ring of structural lighting closest to DOE. Next, for each intensity peak, R _0i is found - the radius of the i-th arc in this direction of scanning along the angle φ. After scanning the entire image, each arc will be described by an array of values R _{0i, φ} . Then, using the approximation of these arrays, the minimum arc radius R _{0i min} is determined, the value of which is proportional to the distance from the optical axis to the surface being monitored. Next, the value of R _{0i min} determines the distance r _i from the surface to be monitored to the optical axis in the section of the ith light ring. The dependence of r _i on R _{0i min} is determined by calculation or during the calibration of the measuring system. Thus, as a result of the described image processing procedure, an array of distances r ₀ , r ₁ , ..., r _n from the surface to be monitored to the optical axis for each light ring (n is the number of light rings) will be calculated by which the geometric parameters of the element are then calculated DR.

In the case of monitoring the overall size of the DR (turnkey size B), measurements are made in two positions of the DR. For each measurement, from the array of numbers r ₀ , r ₁ , ..., r _n , the minimum value is selected, which is then transferred to the Cartesian coordinate system XY ДР 5 taking into account the position of the moving part of the two-coordinate positioning device 6. At the first measurement, the coordinates x ₁ , y ₁ , and in the second - x ₂ , y ₂ , the distance between these points is equal to size B.

When monitoring the holes 13 under the channel, measurements are made in several positions of the DR (according to the number of beetles). For each such measurement, the calculated coordinates r ₀ , r ₁ , ..., r _{n are} translated taking into account the angular position of the beetle into the coordinate system connected by the center of the hole for the channel according to the drawing. Then, the positions of the centers x _{ch i} , y _{ch i} and the diameters D _{ch i of the} inscribed circles for each section are calculated.

When monitoring cell 12 DR 5, the measurement is made in one position DR. In this case, the image will contain several (by the number of beetles) sets of arcs (Fig. 6). According to the coordinates r ₀ , r ₁ , ..., r _n defined for each set of arcs, the positions of the centers X _{ce i} , Y _{ce i} and the diameters D _{ce i of the} inscribed circles for each section of the cell are determined taking into account the angular position of the puppets.

As a source of coherent radiation 1, a semiconductor laser with a beam expander in the form of a collimator can be used.

As a shaper of structural lighting 2, an amplitude diffraction element can be used (L.V. Finogenov. Control of the geometric parameters of holes using a diffraction ring focuser. Automometry, Volume 41, No. 6, 2005, p.23) created using the CLWS laser photop plotter 300 ((Gurenko, VM, Kastorsky, L.V., Kiryanov, VP, Kiryanov, AV, Kokarev, SA, Vedernikov, VM, Verkhoglyad, AG: Laser writing system CLWS-300 / CM for microstructure synthesis an the axisymmetric 3- D surfaces. Proc. SPIE 4900 (2002) pp. 320-325).

As a two-coordinate device for positioning 6 DRs in a plane perpendicular to the optical axis, a two-coordinate motorized table SCAN 300 × 300 by Marzhauser (http://www.marzhauser.com/Pdf/scan300Ч300eng.pdf) can be used.

Lens 8 is similar in characteristics to the lenses used in introscopes.

As the photodetector camera 9, an industrial digital camera PL-A781 from PixeLINK (http://www.pixelink.com) can be used. This camera is built on the basis of a photodiode array of 2208 × 3000 elements. The size of one pixel is 3.5 × 3.5 microns.

A computer based on an AMD Athlon 3200+ processor and 512 MB RAM can be used as an information control and processing unit 11. FireWire controllers (for communication with the camera) and USB (for communication with the motorized table) must be installed on the computer.

Claims (1)

A device for monitoring distance gratings, comprising a coherent radiation source sequentially located on the optical axis, a structural lighting driver, a positioning distance grating device and a photodetector module including a lens and a photodetector camera with a photodetector array connected to a control and information processing unit, the control output of which is connected to a positioning device, characterized in that the shaper of structural lighting is made in the form of differs an optical element based on a phase and / or amplitude microstructure on a transparent substrate containing an opaque region located in the center of the diffractive optical element, a working field that forms a system of light strips on the surface of a controlled fragment of the spacer array, and an alignment field that forms two light rings of the same diameter as the working field for aligning the photodetector module.

Images