JP2007307613A - Apparatus and method for welding strap connections between inner grid straps of spacer grid using laser tool, and spacer grid manufactured using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an apparatus and a method in which fine welding is possible, and the welded bead of each strap connection between inner grid straps can have a small size, the number of welding defects can be reduced, and the pressure drop of a cooling water can be reduced. <P>SOLUTION: An apparatus for welding strap connections between inner grid straps of a spacer grid of a nuclear fuel rod bundle and between inner and outer grid straps includes a pair of welding tools of a round bar shape which are separated from each other at a predetermined space, a connection piece interposed therebetween to connect the welding tools to each other, a laser beam instrument consisting of each optical fiber having an optical fiber connection part which is guided to an upper end of each welding tool to transmit laser beams, and a control unit comprising a supporting piece to be connected to a center of the connection piece of the laser beam instrument, a moving piece connected to the supporting piece, and a straight driving part connected to the moving piece. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a support grid internal inter-grid welding apparatus and welding method using a laser tool, and a support grid manufactured by the welding method. More specifically, the structural strength of the support grid is increased, the phenomenon of welding material scattering and thermal deformation after welding by continuous or intermittent seam welding between the internal grids of the support grid using a laser device. Not only can the welding be reduced and the weld bead size between the support grids can be made smaller, but also the weld flow defects can be reduced and the flow resistance of the cooling water can be reduced by reducing the flow resistance of the cooling water. Can be reduced. The present invention relates to a support grid internal lattice welding apparatus and a welding method using a laser device capable of reducing the load of a cooling water flow pump, and a support grid manufactured thereby.

  In general, the support grid is used to support and fix a bundle of nuclear fuel rods by arranging and combining grid plates engraved with springs and dimples vertically and horizontally and welding the intersections.

  Currently, commercially available support grids are used by joining the intersections of grid plates arranged and combined vertically and horizontally by spot welding, but the welding and welding quality of the intersections contribute to the structural performance of the support grid. It has a great influence.

  Such a support grid can improve the structural performance by improving the welding quality and method of the intersections, thereby greatly improving the characteristics of the nuclear fuel.

Such a light water reactor fuel support grid basically has a welded structure of the inner grid plate intersection, the inner / outer grid plate intersection, and the corner joint of the outer grid plate. When manufacturing a support grid at an industrial company, spot welding is performed using a laser on the external grid, and spot welding is performed at the intersection of the internal crossing plates.

  On the other hand, since the spot welding process of the inner crossing plate currently being performed consists of laser welding using 6 to 7 spots, there is a problem that the welding material scatters around the supporting grid product after welding. there were.

  Not only that, the high heat generated by the laser during the spot welding process can cause dimensional changes and thermal deformation of the support grid, which necessitates additional repair work.

As described above, the method of welding the inner grid plate intersection of the support grid according to the prior art that is manufactured to support the nuclear fuel rods, as shown in FIG. 1, the inner grid plates 140a and 140b of the support grid 100 Intersection welding can be performed at the intermediate joint 150, but such a welding method has a large weld bead size after welding, making delicate welding impossible. There was a serious problem that caused the pressure drop of flowing cooling water.

In such existing support grid welding methods, the welding material scatters after the spot welding is used and thermal deformation occurs, so that delicate welding is impossible. Is a factor that increases the flow resistance of the cooling water by greatly increasing the flow resistance of the cooling water and increasing the cooling water flow pump load. In order to improve the pressure drop, a new support grid welding method needs to be developed.

  The core technology development for that purpose is the development of welding technology using ultra-precision laser and optical transmission equipment. In other words, support grid welding using ultra-precise lasers can greatly increase the structural strength of the support grid while reducing thermal cooling, reducing the cooling water pressure drop with less thermal deformation, enabling delicate welding and reducing the weld area. it can.

  Therefore, the welding method to be developed in the future is an indispensable technology for the development of nuclear fuel for nuclear power plants, and technology development is being actively carried out in many advanced countries in the near future.

In particular, the intersection spot welding method implemented at the upper and lower ends of the support grid has a large weld bead and a severe pressure drop, resulting in a decrease in the flow area and a large increase in the load of the cooling water operation pump. In fact, it is necessary to introduce new tip welding technology to increase the mechanical / structural stability and reduce the pressure drop of the nuclear fuel rod bundle support grid.

  The present invention has been devised in order to solve the above-mentioned problems, and the structural structure of the support grid is obtained by continuously or intermittently seam welding between the internal grids of the support grid using a laser apparatus. Strengthening and reducing the phenomenon of welding material scattering and thermal deformation after welding, enabling delicate welding and not only reducing the weld bead size between support grids, but also reducing defects at the welded part and cooling By reducing the water flow resistance, the pressure drop of the cooling water can be reduced. Accordingly, it is an object of the present invention to provide a support grid internal inter-grid welding apparatus and a welding method using a laser device capable of reducing the load of a cooling water flow pump, and a support grid manufactured thereby.

In order to achieve the above-mentioned object, the present invention provides a support grid inner lattice welding apparatus for welding the lattices of the inner lattice plates and the lattices of the inner / outer lattice plates in the support lattice of the nuclear fuel rod bundle. A cross-section rod-shaped body (hereinafter referred to as a circular bar-shaped body), a pair of welding tools spaced apart from each other by a predetermined distance, a coupling piece interposed between the welding tools to interconnect the welding tools, and the welding A laser device comprising an optical fiber having each optical fiber connection portion for transmitting laser by being pulled into the upper end of the tool, a support piece connected to the central portion of the connection piece of the laser device, and a movement connected to the support piece It comprises a control unit comprising a piece and a linear drive unit connected to the moving piece.

  The welding tool includes an alignment lens provided on an upper side thereof for transmitting an applied laser, a focusing lens provided on the lower side for focusing a laser passing through the alignment lens, and the focusing In order to transmit the laser focused by the lens in a predetermined direction, it is preferable to include a prism provided below the laser.

  Here, the position and angle of the prism form 45 °.

  On the other hand, a laser passage hole through which a laser beam transmitted through a prism passes is formed at a suitable position below the outer peripheral edge of the welding tool.

  In addition, at least one gas line is provided at a proper position of the welding tool, and an end of the gas line is connected to a proper position close to the prism.

  Meanwhile, the welding tool includes an alignment lens provided on an upper side of the welding tool for transmitting an applied laser, and a focusing lens provided on the lower side of the welding tool for focusing the laser that has passed the alignment lens. In order to transmit the laser focused by the focusing lens in a predetermined direction, a copper mirror provided below the laser is included.

  Here, the inclination angle of the copper mirror is 110 °.

  On the other hand, the moving piece is formed so as to be linearly driven in the vertical direction.

  In addition, the linear drive unit is formed so as to be capable of linear drive in the horizontal direction.

  A support grid jig having a grid-shaped fixing home on an upper surface thereof for fixing the support grid; and a welding tool having a plurality of guide holes for fixing the laser tool welding tool in a vertical direction. The structure further includes a jig.

On the other hand, a pair of welding tools spaced apart from each other by a predetermined distance, a connecting piece interposed between the welding tools and connected to each other, and a gas line provided at a proper position of each welding tool to receive gas supply An optical fiber having an optical fiber coupling part for irradiating a laser; a laser instrument sequentially having an alignment lens, a focusing lens and a prism in the inside of each welding tool; and coupled to a central part of a coupling piece of the laser instrument. A control unit having a support piece, a moving piece connected to the support piece and configured to be linearly movable in the vertical direction, and a linear drive unit connected to the moving piece and configured to be driven in the horizontal direction; And a welding method using an internal lattice welding apparatus using a laser tool including a welding tool jig and a support grid jig, the support grid is positioned on the support grid jig. Was a step of fixing, the step of positioning the laser instrument under the control of the control unit x, y, inside interstitial upper predetermined position of the support grid is driven in the z-direction,
A step of inserting the welding tool into a proper position between the inner grids of the supporting grid by adjusting the control unit to drive the moving piece upward and downward, a laser with an optical fiber drawn into the upper end of each welding tool through an optical fiber coupling unit Is transmitted, the laser transmitted through the optical fiber is irradiated on the alignment lens provided on the upper side of each welding tool, the laser irradiated on the alignment lens is aligned and transmitted, and then aligned. A step of focusing on a focusing lens provided on the lower side of the lens, a step of reflecting the laser focused on the focusing lens through a prism provided on the lower side of the lens, and a support grating by a laser transmitted and focused through the prism A step in which laser welding is performed between the inner grids.

  Here, the method further includes a step of inserting each welding tool between the inner lattices of the support lattice while maintaining the vertical direction while being guided by the guide hole of the welding tool jig when the welding tool is inserted and pulled. .

  Meanwhile, the method further includes a step of preventing oxidation of the supporting grid specimen by discharging the protective gas supplied to the gas line.

  Preferably, each welding tool inserted between the inner grids of the support grid further comprises a step of welding continuously or intermittently between the inner grids of the support grid.

  Here, a support grid manufactured by a method of inter-grid welding between support grids using a laser device is included.

(In the present invention having the configuration as described above, the internal lattice of the support lattice using a laser instrument)
Continuous or intermittent seam welding increases the structural strength of the support grid, reduces the phenomenon of welding material scattering and thermal deformation after welding, and enables delicate welding and the weld bead size between the support grids. In addition, the pressure drop of the cooling water can be reduced by reducing the flow resistance of the cooling water by reducing defects at the welding site. As a result, the load of the cooling water flow pump can be reduced, and effects such as improvement in economic efficiency and safety can be obtained.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 2 is a view schematically showing a supporting grid internal interstitial welding apparatus using a laser device according to the present invention, and FIG. 3 is a schematic diagram showing a laser equipment of a supporting grid internal lattice welding apparatus using a laser device according to the present invention. FIG. 4 is a diagram schematically showing a use state of a support grid internal lattice welding apparatus using the laser device according to the present invention, and FIG. 5 is a diagram showing the inside of the support lattice using the laser device according to the present invention. FIG. 6 is a cross-sectional view schematically illustrating a process in which the interstitial welding apparatus is positioned between the internal grids of the support grid and performs laser welding. FIG. FIG. 7 is a perspective view schematically showing a welding tool jig applied to a support grid internal lattice welding apparatus using a laser device according to the present invention, Figure 8, Figure 9, FIG. 10 is a diagram schematically illustrating a process of welding the inner lattices of the support grid using the support lattice inner lattice welding apparatus using the laser device according to the present invention, and FIG. 11 is a diagram illustrating the laser device according to the present invention. FIG. 12 is a flow chart showing an internal welding method of a support grid internal lattice welding apparatus using a laser, and FIG. FIG. 13 is a diagram schematically showing a state in which the gap between the internal grids of the support grid is intermittently welded by the support grid internal grid welding apparatus using the laser apparatus according to the present invention. FIG.

  As shown in the figure, a supporting grid internal inter-grid welding device 1 using a laser device according to the present invention is composed of a laser device 10 and a control unit 30.

The laser tool 10 is a rod-shaped body, a pair of welding tools 10a, 10b spaced apart from each other by a predetermined distance, and a plate-shaped connecting piece 11 interposed between the welding tools 10a, 10b to interconnect each other. Each welding tool 10a, 10b is configured to include an optical fiber 12 that is drawn into and connected to an upper end portion of the welding tool 10a, 10b through an optical fiber connection portion 12a to irradiate a laser.

Here, each of the welding tools 10a and 10b includes an alignment lens 15 on the upper side in order to align the laser beam emitted from the optical fiber 12 drawn and connected to the upper part thereof through the optical fiber connection part 12a. A focusing lens 16 is provided on the lower side to focus the laser that has passed through the lens 15, and a prism 17 is provided on the lower side to refract and transmit the laser focused by the focusing lens 16 at a predetermined angle. .

In an embodiment of the present invention, the lasers aligned through the alignment lens 15 and the focusing lens 16 inside the welding tools 10a and 10b are reflected by the prism 17 spaced a predetermined distance below the laser beam and reflected by the internal grating plate of the support grating 3. 4a and 4b are configured to be laser-welded between the inner lattices 5a and 5b.
If it is easy to laser weld the inner lattice spaces 5a, 5b of the inner lattice plates 4a, 4b, the prism 17 provided in each of the welding tools 10a, 10b can be formed of a convex mirror. .

Each welding tool 10a, 10b includes an alignment lens 15, a focusing lens 16, and a prism 17, but after the irradiated laser is focused, it is reflected and reflected by the inner grid plate 4 of the support grid 3.
If it is easy to weld the inner lattices 5a and 5b of a and 4b, the lenses can be constituted by various other lenses.

Here, the position and angle of the prism 17 are preferably 45 °. That is, the prisms 17 located in the lower side of the welding tools 10a and 10b transmit the laser beams aligned and transmitted through the alignment lens 15 and the focusing lens 16 to the inner grid plates 4a and 4b of the support grid 3. When welding the inner lattices 5a and 5b, it is preferable to set the position and angle of the prism 17 to 45 ° in order to accurately align the welding positions of the irradiated and transmitted laser.

In the embodiment of the present invention, the prism 17 is configured such that the position and angle of the prism 17 are 45 °. However, the laser reflected by the prism 17 is accurately aligned between the inner gratings 5a and 5b of the support grating 3. The position of the prism 17 for irradiation is not limited thereto.

On the other hand, in the embodiment of the present invention, the prism 17 provided in the welding tools 10a and 10b focuses the laser beams emitted from the alignment lens 15 and the focusing lens 16 and then reflects them to reflect the inside of the support grid 3. It is configured to weld the internal lattices 5a and 5b of the lattice plates 4a and 4b, but the prism 17 can be applied in place of a copper mirror (not shown).

  Here, the inclination angle of the copper mirror is preferably 110 °.

On the other hand, the directions of the prisms 17 provided on the lower side inside the welding tools 10a and 10b are symmetrical to each other. That is, when laser welding the inner grids 5a and 5b of the support grid 3, the respective welding tools 10a are used to perform laser welding between the inner grids 5a and 5b at symmetrical positions with each transmitted laser. 10b are arranged at positions symmetrical to each other.

In the embodiment of the present invention, the prism 17 located inside the welding tools 10a and 10b is fixed at a predetermined angle, so that the position and angle of the prism 17 are invariable, and laser welding is performed. Sometimes the prisms 17 are arranged accurately in order to adjust the laser welding position between the inner grids 5a, 5b of the support grid 3.

  On the other hand, a through hole 19 for passing a laser beam transmitted through the prism 17 is formed in a suitable position below the outer peripheral edge of each welding tool 10a, 10b.

  Here, at least one gas line 18 for supplying a protective gas inside the welding tools 10a and 10b is provided at appropriate positions of the welding tools 10a and 10b, and an end portion of the gas line 18 is a prism. Connected to the right place near 17 That is, each of the welding tools 10a, 10b is provided with gas lines 18 that flow from the outside at appropriate positions on the outer peripheral edge, and the ends of the gas lines 18 are provided on the lower inner sides of the welding tools 10a, 10b. It is connected so as to be close to the prism 17.

  Here, the protective gas flowing into the prism 17 of each welding tool 10a, 10b through the gas line 18 is made of argon (Ar).

  As described above, the gas line 18 is connected to each of the welding tools 10a and 10b, and the protective gas is supplied through the gas line 18 to prevent the support grid 3 specimen from being oxidized.

In an embodiment of the present invention, argon (Ar) gas, which is a protective gas, is supplied to the inside of each welding tool 10a, 10b through the gas line 18 to prevent oxidation of the support grid 3 specimen. However, various other protective gases can be supplied through the gas line 18 as long as it is easy to prevent oxidation of the support grid 3 specimen.

  Further, in the embodiment of the present invention, at least one gas line 18 is provided at an appropriate position on the outer periphery of each welding tool 10a, 10b. However, each gas line 18 is connected to each welding tool 10a, 10b. It is also possible to install it so that it can be drawn inside.

  The control unit 30 includes a plate-shaped support piece 31 connected to the central part of the connection piece 11 of the laser instrument 10, a moving piece 33 connected to the end of the support piece 31, and an end of the moving piece 33. It comprises a linear drive unit 35 connected to the.

Here, the moving piece 33 can be driven in the vertical direction, and the linear drive unit 35 can be driven in the horizontal direction. That is, when the moving piece 33 performs laser welding between the inner lattices 5a and 5b of the support lattice 3, the laser tool 10 having a large number of welding tools 10a and 10b is inserted into the inner lattices 5a and 5b of the support lattice 3 and The linear drive unit 35 is formed so as to be driven in the vertical direction to be pulled in, and when the laser welding is performed between the inner grids 5a and 5b of the support grid 3, the laser device 10 having a plurality of welding tools 10a and 10b is provided. The support grid 3 is formed so as to be able to be driven in the horizontal direction so as to be positioned above the inner grids 5a and 5b.

As described above, the laser instrument 10 is positioned above the support grid 3 by the horizontal drive of the linear drive unit 35 and the vertical drive of the movable piece 33, and is positioned above the support grid 3. By inserting and pulling 10 into and between the inner lattices 5a and 5b of the support lattice 3, laser welding between the inner lattices 5a and 5b of the support lattice 3 becomes possible.

  In the embodiment of the present invention, the movable piece 33 is formed so as to be linearly driven in the vertical direction, but the support piece 31 can be formed so as to be driven in the vertical direction.

  In the embodiment of the present invention, the movable piece 33 is formed so as to be linearly driven in the vertical direction, but the movable piece 33 may be formed so as to be linearly driven in the vertical direction and the horizontal direction. .

Here, the supporting grid internal lattice welding apparatus 1 using the laser apparatus according to the present invention is inserted and pulled into the supporting lattice jig 50 for fixing the supporting lattice 3 and the internal lattices 5a and 5b of the supporting lattice 3. It includes a welding tool jig 70 for fixing the vertical guide of each welding tool 10a, 10b and the vertical position of each welding tool 10a, 10b.

For this purpose, the support grid jig 50 is a plate-shaped body, and a plurality of fixing homes 51 for positioning and fixing the support grid 3 are formed on the upper surface of the support grid jig 50 to form a grid shape. Located on the side.

Here, it is preferable that the number of the fixed homes 51 formed on the support grid jig 50 corresponds to the number of unit strap bodies (not shown) of the support grid 3.

  The welding tool jig 70 has a rectangular parallelepiped shape, and has a number of guide holes 71 corresponding to the spaces 5a and 5b between the inner grids of the support grid 3 for inserting the welding tools 10a and 10b.

Here, each guide hole 71 of the welding tool jig 70 is formed in a cylindrical shape to form the welding tool 10a.
, 10b is inserted to maintain the vertical direction.

As described above, the internal grid 5a, 5b of the support grid 3 through the support grid internal grid welding device 1 using the laser apparatus according to the present invention by the support grid jig 50 and the welding tool jig 70.
During welding, the position of the support grid 3 can be easily fixed. When the welding tools 10a and 10b are inserted, the welding tools 10a and 10b are welded while always maintaining the vertical direction between the internal grids 5a and 5b.

  Hereinafter, a method for laser welding an inner lattice of a supporting grid using a supporting lattice inner lattice welding apparatus using a laser apparatus according to the present invention will be described with reference to FIGS.

  First, an operator positions and fixes the support grid 3 on the support grid jig 50 (S11). Here, the lower surface of the support grid 3 is seated and fixed to the fixed homes 51 of the support grid jig 50.

Here, a welding tool jig 70 is installed on the upper surface of the support grid 3 to maintain the vertical direction by inserting the welding tools 10a and 10b (S11-1), and formed on the welding tool jig 70. The guide holes 71 are installed so as to be equal to the spaces formed between the inner lattices 5a and 5b of the inner lattice plates 4a and 4b of the support lattice 3.

  Then, by controlling the control unit 30 to drive the linear drive unit 35 in the horizontal direction, the laser instrument 10 having a pair of welding tools 10a, 10b is provided between the inner lattices 5a of the inner lattice plates 4a, 4b of the support lattice 3. , 5b is positioned at a predetermined position (S12).

That is, the control unit 30 is controlled to drive the linear drive unit 35 in the x, y, and z directions so that the welding tools 10a and 10b of the laser tool 10 are spaced between the internal lattice plates 4a and 4b of the support lattice 3. Located at the top of 5a and 5b.

Then, the control unit 30 is adjusted so that the moving piece 33 is linearly driven in the vertical direction, so that the laser device 10 including the pair of welding tools 10a and 10b is provided between the internal lattice plates 4a and 4b of the support lattice 3. 5a
, 5b is inserted and withdrawn (S13).

Here, each welding tool 10a, 10b is provided between the inner lattice plates 4a, 4b of the support lattice 3 between the inner lattices 5a, 5b.
When b is inserted and pulled, the welding tools 10a and 10b are guided by the guide holes 71 of the welding tool jig 70 and inserted while maintaining the vertical direction (S13-1).

Next, a laser is transmitted to the optical fiber 12 drawn and installed through the optical fiber connection portion 12a at the upper end of each welding tool 10a, 10b (S14), and the transmitted laser is transmitted through the optical fiber 12 to each welding tool 10a, Irradiation is performed from the alignment lens 15 provided on the upper side of 10b (S15).

In this way, after the laser irradiated through the optical fiber 12 drawn into the upper ends of the welding tools 10a and 10b is aligned while passing through the alignment lens 15, the focusing lens 16 provided below the alignment lens 15 is provided. (S16), and the laser focused on the focusing lens 16 is transmitted to the internal lattice plates 4a and 4b of the support lattice 3 between the internal lattices 5a and 5b through the prism 17 provided on the lower side thereof. And converge (S17).

Here, when the prism 17 is applied in place of a copper mirror (not shown), the laser that is aligned and focused through the alignment lens 15 and the focusing lens 16 is reflected by the copper mirror and is reflected by the internal grating of the support grating 3. The plates 4a and 4b are transmitted to the inter-lattice 5a and 5b welding sites and welded while converging.

Here, by setting the inclination angle of the copper mirror to 110 °, the laser can be easily transmitted to the welding site.

The supporting grating 3 is thus transmitted by the laser transmitted through the prism 17 and focused.
Laser welding is performed on each side surface of the inner lattice plates 4a, 4b facing each other between the inner lattices 5a, 5b (S18).

As described above, each laser irradiated and focused through the welding tools 10a and 10b inserted and drawn into the inner lattice 5a and 5b between the inner lattices of the support lattice 3 is applied to the inner lattice plates 4a and 4b of the support lattice 3. By performing laser welding simultaneously on the mutually opposing side surfaces of the inner lattices 5a and 5b, the highest penetration can be obtained, and the welding strength between the inner lattices 5a and 5b of the support lattice 3 can be strengthened.

Here, each welding tool 10a, 10b inserted and pulled into the inner lattices 5a, 5b of the inner lattice plates 4a, 4b of the support lattice 3 is continuous or intermittent between the inner lattices 5a, 5b of the support lattice 3. (S18-1). That is, each welding tool 10a inserted into the inner lattice 5a, 5b of the support lattice 3
, 10b welds the entire inner lattice 5a, 5b of the supporting lattice 3 by continuously irradiating a laser while moving from the upper direction to the lower direction or from the lower direction to the upper direction within the inner lattice 5a, 5b. The laser is intermittently irradiated to weld only predetermined portions between the inner lattices 5a and 5b of the support lattice 3.

At this time, the vertical movement speeds of the welding tools 10a and 10b inserted into the inner grids 5a and 5b of the support grid 3 and continuously or intermittently welded are made equal.

With the structure as described above, the welding tools 10a and 10b are supported by the inner grid plates 4a and 4b of the support grid 3.
Are inserted and pulled into the inner grids 5a and 5b of the support grid 3, and the entire sides of the inner grid 5a and 5b of the support grid 3 are continuously laser welded, or the upper, middle and lower sides of the inner grid 5a and 5b of the support grid 3 Only a predetermined part such as the side can be intermittently laser-welded.

Thus, the welding tools 10a, 10b inserted and drawn into the inner lattices 5a, 5b of the inner lattice plates 4a, 4b of the support lattice 3 as shown in FIG. 12 show the inner lattices 5a, 5b. As shown in FIG. 13, the inner lattice 5a, 5b is intermittently partially welded only at a specific portion, as shown in FIG. Join 5b.

As described above, after laser welding the inner lattices 5a, 5b of the inner lattice plates 4a, 4b of the support lattice 3, the laser between the remaining inner lattices of the support lattice 3 is repeatedly laser-welded. Laser welding is completed through the support grid internal interstitial welding device 1 using an instrument.

  At this time, a protective gas is supplied through the gas line 18 to each welding tool 10a, 10b irradiated with a laser through the optical fiber 12, and oxidation of the support lattice specimen is prevented by discharging the supplied protective gas (S17-1). ).

  As described above, the protective gas supplied through the gas line 18 is not only responsible for preventing oxidation of the support grid specimen during laser welding but also responsible for protecting the prism 17.

  FIG. 14 is a perspective view schematically showing another embodiment of a supporting grid internal interstitial welding apparatus using a laser device according to the present invention, in which the structure of a welding tool is partially changed.

As shown in the figure, in this embodiment, the internal grid plates 4a, 4b of the support grid 3 are changed by changing the number of welding tools 10a, 10b, 10c, 10d of the support grid internal grid welding apparatus 1 using a laser tool. It is possible to perform laser welding simultaneously on each side of the inner lattices 5a, 5b, 5c, 5d, that is, in four directions.

That is, a welding formed by forming a rod-shaped body, an optical fiber 12 having an optical fiber coupling portion 12a at the upper end thereof, and sequentially having an alignment lens 15, a focusing lens 16 and a prism 17 in the downward direction therein. Four tools 10a, 10b, 10c, and 10d are provided at a predetermined distance from each other, and are inserted into and pulled into the inner lattices 5a, 5b, 5c, and 5d of the support lattice 3.

As described above, the laser instrument 10 includes the four welding tools 10a, 10b, 10c, and 10d, so that the inner grids 5a, 5b, 5c, and 5d of the inner grid plates 4a and 4b of the support grid 3 are provided. Each welding tool 10a, 10b, 10c, 10d inserted and withdrawn into the inner lattice 5a, 5b, 5c, 5d between the inner lattice 5a, 5b, 5d, by simultaneously laser welding the inner lattice 5a, 5b, 5c, 5d laser welding can be performed more quickly and easily.

For this purpose, the welding tools 10a, 10b, 10c, and 10d are connected to each other by a predetermined distance from each other by a connecting piece 11, and laser beams emitted from the welding tools 10a, 10b, 10c, and 10d are applied to the support grid 3. A prism 17 is provided on the inner lower side of each welding tool 10a, 10b, 10c, 10d so as to be concentrated at the center of the inner lattices 5a, 5b, 5c, 5d of the inner lattice plates 4a, 4b.

  Also in this embodiment, the prism 17 provided on the lower side inside the welding tools 10a, 10b, 10c, and 10d can be applied in place of a copper mirror (not shown). The angle is preferably 110 °.

On the other hand, in the embodiment, the laser instrument 10 is configured to include four welding tools 10a, 10b, 10c, and 10d, but the laser instrument 10 may be configured to include 16 welding tools. The number of welding tools of the laser instrument 10 is not limited to the above number.

Again, as shown in FIGS. 6 and 7, the inside of the support grid jig 50 having the grid-shaped fixing home 51 and the internal grid plates 4a and 4b of the support grid 3 to fix the support grid 3 Multiple to fix the vertical direction of each welding tool 10a, 10b, 10c, 10d and the vertical position of each welding tool 10a, 10b, 10c, 10d inserted and withdrawn into the interstitial 5a, 5b, 5c, 5d It is preferable to include a welding tool jig 70 having a guide hole 71.

  The preferred embodiments of the present invention have been described above by way of example. However, the scope of the present invention is not limited to such specific embodiments, and those having ordinary knowledge in the pertinent field can apply for the patent of the present invention. Appropriate modifications may be made within the scope of the claims.

  As described above, according to the present invention having the above-described configuration, the structural strength of the support grid is enhanced by continuously or intermittently seam welding between the internal grids of the support grid using a laser device. In addition to reducing the phenomenon of welding material scattering and thermal deformation after welding, it is possible not only to form a small weld bead size between the support grids, but also to reduce defects at the welded part, thereby reducing the flow of cooling water. By reducing the resistance, the pressure drop of the cooling water can be reduced. As a result, the load of the cooling water flow pump can be reduced, and effects such as improvement in economic efficiency and safety can be obtained.

The figure which shows roughly the intersection welding state between the support grid inside lattices of a nuclear fuel rod bundle using the support lattice welding apparatus of the nuclear fuel rod bundle by a prior art. The figure which shows roughly the support grid internal lattice welding apparatus using the laser instrument by this invention. FIG. 3 is a cross-sectional view schematically showing a laser device of a supporting grid internal inter-grid welding apparatus using the laser device according to the present invention. The figure which shows roughly the use condition of the support grid internal lattice welding apparatus using the laser instrument by this invention. FIG. 3 is a cross-sectional view schematically showing a process of laser welding by a support grid internal lattice welding apparatus using a laser apparatus according to the present invention located between the internal lattices of a support lattice. The perspective view which shows schematically the support grid jig | tool applied to the support grid internal grid welding apparatus using the laser instrument by this invention. The perspective view which shows schematically the welding tool jig | tool applied to the support grid internal lattice welding apparatus using the laser instrument by this invention. The figure which shows schematically the process of welding between the internal grids of a support grid using the support grid internal grid welding apparatus using the laser instrument by this invention. The figure which shows schematically the process of welding between the internal grids of a support grid using the support grid internal grid welding apparatus using the laser instrument by this invention. The figure which shows schematically the process of welding between the internal grids of a support grid using the support grid internal grid welding apparatus using the laser instrument by this invention. The flowchart which shows the internal welding method of the support grid internal lattice welding apparatus using the laser instrument by this invention. The figure which shows roughly a mode that the space between the internal grids of a support grid was continuously welded by the support grid internal grid welding apparatus using the laser instrument by this invention. The figure which shows roughly a mode that the space between the internal grids of a support grid was intermittently welded by the support grid internal grid welding apparatus using the laser instrument by this invention. The perspective view which shows schematically the other Example of the support grid internal lattice welding apparatus using the laser instrument by this invention.

Explanation of symbols

1: Support grid internal interstitial welding equipment using laser equipment, 3: Support grid, 4a, 4b: Internal grid plate, 5a, 5b, 5c, 5d: Internal grid, 6: Cross spot welding bead, 10: Laser Instruments, 10a, 10b, 10c, 10d: Welding tool, 11: Connecting piece, 12: Optical fiber, 12a: Optical fiber connection, 15: Alignment lens, 16: Focusing lens, 17: Prism, 18: Gas line, 19: Pass Hole: 30: control unit, 31: support piece, 33: moving piece, 35: linear drive unit, 50: support grid jig, 51: fixed home, 70: welding tool jig, 71: guide hole.

Claims (15)

In the support grid 3 of the nuclear fuel rod bundle, in the support grid internal lattice welding apparatus 1 for welding the lattices of the internal lattice plates 4a, 4b and the lattices of the internal / external lattice plates, A pair of welding tools 10a, 10b spaced apart from each other by a predetermined distance, a connecting piece 11 interposed between the welding tools 10a, 10b to connect the welding tools 10a, 10b, and the welding tools 10a, 10b. A laser device 10 comprising optical fibers 12 having an optical fiber connection portion 12a for being transmitted to the upper end of the laser device, and a support piece 31 connected to the central portion of the connection piece 11 of the laser device 10, and the support A supporting grid internal inter-grid welding apparatus using a laser instrument, comprising: a moving piece 33 coupled to the piece 31; and a control unit 30 comprising a linear drive unit 35 coupled to the moving piece 33. The welding tool 10a, 10b includes an alignment lens 15 provided on the upper side thereof for transmitting an applied laser, and a focusing device provided on the lower side thereof for focusing the laser passing through the alignment lens 15. 2. The lens 16 and a prism 17 provided below the lens 16 for transmitting the laser beam focused by the focusing lens 16 in a predetermined direction.
A support grid internal interstitial welding apparatus using the laser apparatus described in 1. 3. The supporting grid internal lattice welding apparatus using a laser device according to claim 2, wherein the prism 17 has a position and an angle of 45 °. The laser instrument according to claim 2, wherein a laser passage hole 19 is formed through the laser beam transmitted through the prism 17 at a position below the outer peripheral edge of the welding tool 10a, 10b. Support grid internal interstitial welding equipment. The welding tools 10a and 10b are provided with at least one or more gas lines 18 at appropriate positions, and ends of the gas lines 18 are connected to appropriate positions close to the prism 17.
A support grid internal interstitial welding apparatus using the laser apparatus described in 1. The welding tool 10a, 10b includes an alignment lens 15 provided on the upper side thereof for transmitting an applied laser, and a focusing device provided on the lower side thereof for focusing the laser passing through the alignment lens 15. The lens 16 and a copper mirror provided on the lower side of the lens 16 in order to transmit the laser focused by the focusing lens 16 in a predetermined direction.
A support grid internal interstitial welding apparatus using the laser apparatus described in 1.   7. The support grid internal inter-grid welding apparatus using a laser device according to claim 6, wherein the copper mirror has an inclination angle of 110 °. 2. The support grid internal lattice welding apparatus using a laser device according to claim 1, wherein the moving piece 33 is formed so as to be linearly driven in the vertical direction.   2. The support grid internal lattice welding apparatus using a laser device according to claim 1, wherein the linear drive unit 35 is formed to be capable of linear drive in a horizontal direction. In order to fix the support grid 3, a support grid jig 50 having a grid-shaped fixing home 51 on the upper surface thereof, and a plurality of guides for fixing the welding tools 10a and 10b of the laser apparatus 10 in the vertical direction. 2. The laser-supported inter-lattice interstitial welding apparatus according to claim 1, further comprising a welding tool jig 70 having holes 71. A pair of welding tools 10a and 10b spaced apart from each other by a predetermined distance, a connecting piece 11 interposed between the welding tools 10a and 10b and connected to each other, and the welding tools 10a and 10b are provided at appropriate positions. Gas line 18 that receives gas supply, and optical fiber connection 12a for laser irradiation
An optical fiber 12, a laser tool 10 having an alignment lens 15, a focusing lens 16, and a prism 17 sequentially in the inside of each of the welding tools 10 a and 10 b, and a connecting piece 11 at the center of the laser tool 10. A support piece 31, a moving piece 33 connected to the support piece 31 so as to be linearly movable in the up-and-down direction, and a linear drive unit 35 connected to the moving piece 33 and capable of being driven in the horizontal direction. In a welding method by a support grid internal inter-grid welding apparatus using a laser instrument comprising a control unit 30 and a welding tool jig and a support grid jig,
The support grid 3 is positioned and fixed to the support grid jig 50 (S11),
A step of driving the laser instrument 10 in the x, y and z directions under the control of the control unit 30 to position the inner lattice plates 4a and 4b between the inner lattice plates 5a and 5b of the support lattice 3 at predetermined positions (S12),
Adjusting the control unit 30 to drive the moving piece 33 in the vertical direction and inserting the welding tools 10a, 10b between the inner grids 5a, 5b of the support grid 3 (S13),
A step of transmitting a laser with the optical fiber 12 drawn through the optical fiber connecting portion 12a to the upper end of each welding tool 10a, 10b (S14),
A step of irradiating a laser beam transmitted through the optical fiber 12 from an alignment lens 15 provided on the upper side of each welding tool 10a, 10b (S15),
After the laser beams emitted from the alignment lens 15 are aligned and transmitted, the laser beam is focused on the focusing lens 16 provided on the lower side of the alignment lens 15 (S16),
The step of reflecting the laser beam focused on the focusing lens 16 through the prism 17 provided on the lower side thereof (S17),
A step (S18) in which laser welding is performed between the inner lattices 5a and 5b of the inner lattice plates 4a and 4b of the support lattice 3 by the laser transmitted and focused through the prism 17;
A welding method using an interstitial inter-grid welding device using a laser device, characterized by comprising: While the welding tools 10a, 10b are inserted and pulled into the inner grids 5a, 5b of the support grid 3, the welding tools 10a, 10b are guided by the guide holes 71 of the welding tool jig 70 while maintaining the vertical direction. 12. The welding method using the interstitial inter-grid welding device using a laser device according to claim 11, further comprising an insertion step (S13-1). The laser apparatus according to claim 11, further comprising a step (S17-1) of preventing oxidation of the support lattice specimen by discharging a protective gas supplied to the gas line 18. Welding method using interstitial welding equipment inside support grid. Each welding tool 10a, 10b inserted in the inner grid 5a, 5b of the support grid 3 further includes a step (S18-1) of welding the inner grid 5a, 5b of the support grid 3 continuously or intermittently. 12. A welding method using a support grid internal lattice welding device using the laser device according to claim 11, wherein the welding method is performed by using the laser device according to claim 11.   15. A support grid manufactured by a method for inter-grid welding of a support grid using the laser device according to claim 11 or 14.

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