KR100906719B1 - Welding Rod for LASER Welding Apparatus and LASER Welding Apparatus for Inner-Strap of Spacer Grids of Nuclear Fuel Rod using this - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser welding device between a welding rod for a laser welding device and an inner lattice of a nuclear fuel rod support lattice using the same. The present invention relates to a continuous or intermittent inner strap connection of a lattice using a laser. Seam welding increases the structural strength of the support grid, reduces spattering and thermal deformation of the welding material after welding, and enables delicate welding to reduce the weld bead size between the support grids. In addition to reducing the flow resistance of the coolant, it is possible to reduce the pressure drop of the coolant, to reduce the load of the coolant flow pump, and to improve the economics and safety. In order to provide laser welding device between inner lattice of used fuel rod support lattice, it is cylindrical type An optical fiber for transmitting the laser, one end of which is inserted into an upper end of the housing and transmitting a laser, and an alignment lens provided at an upper portion of the housing to align the laser irradiated through the optical fiber in parallel with each other; A focusing lens provided at a lower portion to focus the laser beam passing through the alignment lens at a point; a reflection mirror having an inclined surface reflecting the laser focused at a point by the focusing lens; and the laser beam reflected from the reflection mirror. In the electrode for a laser welding device comprising a through-hole formed on one side of the housing for the passage, the angle between the normal of the inclined surface of the reflective mirror and the axis of the housing is in the range of 57.5 ° ~ 67.5 ° It is characterized by having.

Spacer Grid, Inner Strap Connection, Laser Welding Appratus, Welding Rod, Control Part, Continuous, Intermittent

Description

Welding rod for laser welding device and laser welding device between inner lattice of nuclear fuel rod support grid using the same {Welding Rod for LASER Welding Apparatus and LASER Welding Apparatus for Inner-Strap of Spacer Grids of Nuclear Fuel Rod using this}

1 is a view schematically showing a spot welding state of a nuclear fuel rod support grid according to the prior art,

Figure 2 schematically shows a welding rod for a laser welding device of the nuclear fuel rod support grid according to the prior art,

3 is a view schematically showing a welding rod for a laser welding device according to the present invention;

Figure 4 is a schematic diagram showing the angle of the laser reflected by the reflective mirror of the electrode for laser welding apparatus according to the present invention,

5 is a perspective view showing a reflection mirror of a welding rod for a laser welding device according to the present invention;

6 is a view showing the results of experiments on the welding surface and the cross-sectional shape according to the angle of the inclined surface of the reflective mirror of the electrode for laser welding apparatus according to the present invention,

7 is a view schematically showing a laser welding device of the nuclear fuel rod support grid according to the present invention,

8 is a view schematically showing a state of use of the laser welding device of the nuclear fuel rod support grid according to the present invention,

9 is a view schematically showing a state in which the welding between the internal lattice of the support grid by the laser welding device of the nuclear fuel rod support grid according to the present invention (Continuous),

10 is a view schematically showing the appearance of the intermittent welding between the internal lattice of the support grid by the laser welding device of the nuclear fuel rod support grid according to the present invention,

** Explanation of symbols for main parts of the drawing **

1: laser welding device between the internal lattice of the fuel rod support grid,

3: support lattice, 5a, 5b: between internal lattice,

10: welding rod, 10a: housing,

11: connecting piece, 12: optical fiber,

15: alignment lens, 16: focusing lens,

17: reflection mirror, 17a: inclined surface,

18 gas line, 19 laser passing hole,

30: control unit, 31: support piece,

33: moving piece, 35: linear drive part,

The present invention relates to a welding electrode for a laser welding device and a laser welding device between the inner lattice of the nuclear fuel rod support grid using the same. More specifically, the inner strap connection between the inner lattice of the lattice using the laser mechanism (Continuous) ) Or intermittent seam welding to increase structural strength of support grid, reduce spattering and thermal deformation of welding material after welding, and allow delicate welding to weld weld beads between support grids In addition to reducing the bead size, it is possible to reduce the pressure drop of the coolant by reducing defects in the welded part and reducing the flow resistance of the coolant, thereby reducing the load of the coolant flow pump. Welding rod for laser welding device and laser welding device between inner lattice of nuclear fuel rod support grid using same It relates.

In general, the support grid is for supporting and fixing a bundle of nuclear fuel rods by welding cross sections by arranging and weaving a lattice in which springs and dimples are imprinted horizontally and vertically.

Currently, commercially supplied support grids are used by spot welding the intersections of horizontally and vertically arranged and woven grids, and the welding and welding quality at the intersections have a great influence on the structural performance of the support grids. Are going crazy.

These support grids can improve the structural performance by improving the welding quality and method of the intersection, which can greatly improve the characteristics of the nuclear fuel rods.

These fuel cell support grids form a welded structure of the inner grating intersections, the inner / outer grating intersections, and the corner joints of the outer gratings. Spot welding is carried out using a laser, and spot welding is performed at the intersection of the internal cross plates.

On the other hand, since the spot welding process of the inner cross plate is currently performed by laser welding using 6 to 7 spots, there is a problem that spattering of the welding material occurs due to welding around the support grid product after welding.

In addition, due to the high heat generated by the laser during the spot welding process, the dimension change and thermal deformation of the support lattice may occur, which may cause additional repair work.

As described above, the method for welding the internal lattice intersection point of the support lattice according to the related art manufactured to support the nuclear fuel rod, as shown in FIG. Although performed using cross point welding at 150, this welding method has a large size of the weld bead after welding, a delicate welding is impossible, and a pressure drop of the coolant flowing in the core due to the large weld bead. There was a deepening problem.

In the conventional support grid welding method, spot welding and heat deformation occur after welding using spot welding, so delicate welding is impossible. Increasing the pressure drop of the coolant ultimately increases the load on the coolant flow pump, and it is necessary to develop a new support grid welding method to improve the structural strength of the support grid and to improve the pressure drop. There is.

For this purpose, the core technology development is welding development using ultra-precision laser and light transmission mechanism. In other words, the support grid welding using the ultra-precision laser has a small thermal deformation and enables delicate welding, so that the welding area is small, and the structural strength of the support grid can be greatly increased while reducing the pressure drop of the cooling water.

Therefore, the welding method to be developed in the future is an essential technology for developing nuclear fuel rods for nuclear power plants, and is expected to be actively developed in various countries in the near future.

In particular, the intersection spot welding method, which is carried out at the top and bottom of the support grid, has a large pressure drop due to the large welding bead, which leads to a decrease in the flow area, which greatly increases the load of the coolant operation pump and increases the design margin of the reactor structure. As a result of this reduction, new advanced welding technologies are needed to increase the mechanical / structural stability and reduce the pressure drop of the fuel rod bundle support grid.

In order to solve the above problem, the present applicant has already filed an inter-lattice welding apparatus using a laser mechanism having a reflecting surface formed at an angle of 45 ° through Patent Application No. 2006-81049.

However, since the support grid of the reactor is divided into a narrow space of 12.5 mm x 12.5 mm square inside, a laser mechanism is inserted into the space, and the inner grid between welded parts is welded. The distance between the through holes of the laser device is close, and the support grid, which is the welded object, is generally made of Zircaloy with high reflectivity, so that the laser reflected through the inclined surface at an angle of 45 ° enters the welded portion perpendicularly. Plasma and fume generated during welding come into contact with the inclined surface, thereby degrading the performance of the electrode, which in turn lowers the welding quality and shortens the life of the laser welding machine.

The present invention has been made to solve the above problems, by using a laser to continuously weld the inner grating (Inner Strap Connection) of the lattice (Continuous or Intermittent (Seam) seam (Seam Welding) of the support lattice It increases structural strength and reduces spattering and thermal deformation of welding materials after welding, and enables delicate welding to reduce the size of welding beads between support grids, as well as to reduce defects in welded areas. By reducing the flow resistance of the cooling water, the pressure drop of the cooling water can be reduced, thereby reducing the load of the cooling water flow pump, and the plasma and smoke generated in the welded object during welding. Laser beam is inclinedly irradiated between inner lattice to be welded so that) For stitching device for a laser capable of electrode and between them with the interior of the fuel rod support grid grating and an object thereof is to provide a laser welding apparatus.

In order to achieve the above object, the present invention provides a cylindrical housing; An optical fiber having one end inserted into an upper end of the housing and transmitting a laser beam; An alignment lens provided at an upper portion of the housing to align lasers irradiated through the optical fiber in parallel; A focusing lens provided under the alignment lens to focus the laser beam passing through the alignment lens at a point; A reflection mirror having an inclined surface reflecting the laser focused at a point by the focusing lens; In the welding rod for a laser welding device comprising a through-hole formed on one side of the housing for the laser reflected from the reflective mirror to pass, the angle of the normal of the inclined surface of the reflective mirror and the axis of the housing 57.5 It is in the range of 6 ° to 67.5 °, and the angle is particularly preferably 60 °.

In addition, the reflecting mirror is made of a metal material, it is preferable that the reflector is made of a good copper material.

In addition, the alignment lens is characterized in that the upper portion is a plane and the lower portion is made of a convex surface, the focusing lens is the upper portion is a convex surface and the lower portion is made of a plane.

In addition, the present invention provides a laser welding apparatus for a nuclear fuel rod support lattice for welding between the internal lattice of the support lattice of the nuclear fuel rod bundle, comprising: a laser generator; An optical fiber for transmitting a laser generated by the laser generator; A cylindrical housing having one end of the optical fiber introduced into an upper end portion thereof, an alignment lens provided inside the housing to align the laser beam transmitted through the optical fiber in parallel, and a lower portion of the alignment lens provided at the lower portion of the alignment lens. A reflection lens having a focusing lens for connecting the laser beams passing through the point, an inclined surface for reflecting the laser focused at one point by the focusing lens between the internal lattice of the support grid, and the laser reflected from the reflection mirror. A pair of electrodes having a through-hole formed through one side of the housing to pass therethrough; A connecting piece interposed therebetween to connect the pair of electrodes to each other; And a control unit comprising a support piece connected to the center of the connection piece, a moving piece connected to the support piece, and a linear driving part connected to the moving piece.

On the other hand, the moving piece is made of a linear drive in the up, down direction, the linear drive is made of a linear drive in the horizontal direction.

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

3 is a view schematically showing a welding rod for a laser welding device according to the present invention, Figure 4 is a schematic diagram showing the angle of the laser reflected by the reflection mirror of the welding rod for a laser welding device according to the present invention, Figure 5 6 is a perspective view showing a reflection mirror of a welding rod for a laser welding device according to the present invention, and FIG. 6 is a view showing a result of experimenting with a welding surface and a cross-sectional shape according to the angle of the inclined surface of the reflecting mirror of the welding rod for a laser welding device according to the present invention. 7 is a view schematically showing a laser welding device of the nuclear fuel rod support grid according to the present invention, Figure 8 is a view showing a state of use of the laser welding device of the nuclear fuel rod support grid according to the present invention, Figure 9 Is continuous between the internal lattice of the support lattice by the laser welding device of the nuclear fuel rod support lattice according to the present invention (Continuous) is a view schematically showing the appearance, Figure 10 is a schematic view showing the intermittent welding between the internal lattice of the support grid by the laser welding device of the nuclear fuel rod support grid according to the present invention It is a figure which shows.

As shown in FIG. 3, the electrode 10 for laser welding apparatus according to the present invention includes a cylindrical housing 10a; An optical fiber 12 having one end inserted into an upper end of the housing 10a and transmitting a laser beam; An alignment lens 15 provided above the housing 10a to align the laser beams irradiated through the optical fiber 12 in parallel; A focusing lens 16 provided below the alignment lens 15 to focus the laser beam passing through the alignment lens 15 to a point; A reflection mirror having an inclined surface 17a for reflecting the laser focused at a point by the focusing lens 16; In order to pass the laser beam reflected from the reflective mirror 17 is made of a through-hole formed through the laser passing hole 19 on one side of the housing (10a).

The housing 10a has a cylindrical shape with an empty inside such that the optical fiber 12, the alignment lens 15, the focusing lens 16, and the reflection mirror 17 are sequentially installed therein, and at an upper end thereof. One end of the optical fiber 12 is inserted and installed.

The optical fiber 12 performs a function of transferring the laser generated by the laser generator separately provided into the housing 10a.

The alignment lens 15 has a flat upper surface and a lower convex surface so that the laser irradiated radially from the optical fiber 12 may be parallel to the axial direction of the housing 10a. The laser beam irradiated from the optical fiber 12 is refracted and travels in parallel with the axial direction of the housing 10a.

The focusing lens 16 has a convex surface at the top and a flat surface at the bottom thereof, and collects the laser beams refracting parallel to each other through the alignment lens 15 into one point.

As shown in FIG. 4, the reflection mirror 17 has its normal to be inclined to irradiate the laser collected at one point by the focusing lens 16 to the inner grids 5a and 5b of the support grid 3 as the welded object. The angle θ formed with the axis of the housing 10a has an inclined surface 17a having a range of 57.5 ° to 67.5 °.

That is, the laser reflected by the inclined surface 17a of the reflective mirror 17 having the angle range does not enter the welded portion perpendicularly but has an angle of incidence of 30 ° to 60 °.

In addition, the reflective mirror 17 is formed by inclining the cylindrical metal rod inclined as shown in Figure 5, the angle of the normal line of the inclined surface 17a and the axis has a range of 57.5 ° ~ 67.5 °, more preferably Preferably it is to have an angle of 60 °.

The penetration depth of the welded portion and the size of the weld bead between the inner lattice 5a and 5b of the nuclear rod support lattice 3 must be maintained at a constant level to maintain the strength of the support lattice 3 and reduce the flow resistance of the coolant. In general, the penetration depth should be in the range of 150 to 250 μm, and the size of the weld bead is preferably in the range of 500 to 700 μm.

Applicant is the penetration depth and the size of the weld bead between the inner lattice (5a, 5b) of the support grid (3) according to the angle that the normal of the inclined surface (17a) of the reflective mirror 17 and the axis of the housing (10a) Experiments were carried out for the results shown in Table 1.

Angle (θ) Penetration depth (㎛) Size of weld bead (㎛) 45 240 648 57.5 195 607 60 195 574 67.5 190 528

In addition, a weld surface and a cross-sectional shape thereof are shown in FIG. 6. FIG. 6 (a) is a 50 times magnification of the weld surface and its cross section when the angle between the normal of the inclined surface 17a and the axis of the housing 10a is 45 °, and FIG. 6 (b) is the inclined surface 17a. The welding surface and its cross section are enlarged 50 times when the angle formed by the normal line of the axis and the axis of the housing 10a is 57.5 °, and FIG. 6 (c) shows that the normal line of the inclined surface 17a and the axis of the housing 10a are The welding surface and its cross section are enlarged 50 times when the angle formed is 60 °, and FIG. 6 (d) shows the weld surface when the angle formed by the normal of the inclined surface 17a and the axis of the housing 10a is 67.5 °. And its cross section is enlarged 50 times.

In addition, the reflective mirror 17 is made of a smooth metal surface, it is particularly preferred to use a copper material.

The laser passing hole 19 is formed to penetrate the lower side of the housing (10a), it is preferable to penetrate toward the to-be-welded portion so that the laser reflected from the reflective mirror 17 is irradiated toward the to-be-welded portion.

In addition, the laser welding device 1 between the internal lattice of the nuclear fuel rod support grid according to the present invention is a laser generator (not shown) and an optical fiber for transmitting the laser generated by the laser generator as shown in FIG. A pair of electrodes 10 consisting of a cylindrical housing 10a into which one end of the optical fiber 12 is led at an upper end portion thereof, and a pair of electrodes 10 for connecting the pair of electrodes 10 to each other; It is comprised by the connection piece 11 interposed and the control part 30.

The laser generator is a Nd: YAG laser generator generally used, the average output is preferably 40W, the energy per pulse of about 1J level is preferably used.

The optical fiber 12 is connected and installed between the laser generator and the pair of electrodes 10 so as to transmit the laser generated by the laser generator to the pair of electrodes 10, respectively.

The welding rod 10 has a cylindrical housing 10a in which one end of the optical fiber 12 is introduced into an upper end portion thereof, and a laser beam provided through the optical fiber 12 is arranged in parallel with each other in the housing 10a. An alignment lens 15 and a focusing lens 16 provided below the alignment lens 15 to focus the laser beam passing through the alignment lens 15 at a single point, and the focusing lens 16. A reflection mirror 17 having an inclined surface 17a for reflecting the laser focused at a point by the point to the internal lattice 5a, 5b of the support grid 3, and the laser reflected from the reflection mirror 17 In order to pass through is made of a through-hole laser 19 formed on one side of the housing (10a).

Here, it is such that the angle between the normal line of the inclined surface 17a of the reflective mirror 17 and the axis of the housing 10a is in the range of 57.5 ° to 67.5 °. The incident angle of the laser incident on 5a and 5b) is in the range of 30 ° to 60 °.

Therefore, the plasma and the smoke generated by the laser at the incidence angle having a range of 30 ° to 60 ° compared to the conventionally incident laser can directly reflect the reflection mirror 17 surface of the electrode 10. You can prevent it from being delivered.

On the other hand, the direction of each reflective mirror 17 provided in the inner lower side of each electrode 10 is symmetric with each other. That is, in the case of laser welding the inner lattice 5a, 5b of the support grid 3, each of the welding rods for laser welding the inner lattice 5a, 5b at positions symmetrical with each other to be transmitted are laser beams. Each of the reflection mirrors 17 provided on the inner lower side of the 10 is located symmetrically with each other.

In addition, at least one gas line 18 for supplying an Assistant Gas into the welding rod 10 in place of the housing 10a of each of the welding rods 10 may be a support grid. A protective gas for preventing oxidation of the inner lattice 5a, 5b of (3) is supplied.

That is, gas lines 18 flowing from the outside are provided in the outer periphery of the housing 10a of each of the welding rods 10, and ends of the respective gas lines 18 are internally lower side of the welding rods 10. Speaked close to the reflection mirror 17 provided in the.

At this time, the protective gas flowing into the reflective mirror 17 of each electrode 10 through the gas line 18 is made of argon (Ar).

As described above, a gas line 18 is connected to each of the welding rods 10 and supplies a protective gas through the gas line 18 so that the inner grids 5a and 5b of the support grid 3 are connected to each other. Oxidation can be prevented.

In an embodiment of the present invention, argon (Ar) gas, which is a protective gas, is supplied to each of the welding rods 10 through the gas line 18 to oxidize the internal grids 5a and 5b of the support grid 3. Although it is configured to prevent, if it is easy to prevent the oxidation of the inner lattice (5a, 5b) between the internal lattice of the support grid (3) it is also possible to supply a variety of other protective gas through the gas line (18).

The connecting piece 11 is formed in a plate shape and is installed at one side of the outer periphery of the housing 10a of the pair of welding rods 10 to connect the pair of welding rods 10 to each other.

The control unit 30 is connected to a plate-shaped support piece 31 connected to the center of the connection piece 11 and a moving piece 33 connected to an end of the support piece 31 and an end of the moving piece 33. It consists of a linear drive unit 35 to be connected.

Here, the movable piece 33 is made to be driven in the vertical direction, the linear drive unit 35 is made to be driven in the horizontal direction. That is, when the movable piece 33 laser welds the inner lattice 5a, 5b of the support lattice 3, the plurality of welding rods 10 are connected to the inner lattice 5a, 5b of the support lattice 3 by the laser beam. It is made to be driven in the vertical direction in order to insert and draw in, the linear drive unit 35 when the laser lattice between the inner lattice (5a, 5b) of the support grid 3, a plurality of welding rod 10 support grid It is made to be driven in the horizontal direction so as to be located above the inner lattice (5a, 5b) of (3).

As described above, the welding rod 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. Laser welding of the inner lattice 5a, 5b of the support lattice 3 is possible by inserting and retracting the welding rod 10 located on the upper part of the lattice lattice 5a, 5b of the support lattice 3. .

In the embodiment of the present invention, the movable piece 33 is configured to be linearly driven in the vertical direction, but it is also possible that the support piece 31 can be driven in the vertical direction.

In addition, in the embodiment of the present invention, the movable piece 33 is configured to be linearly driven in the vertical direction, but the movable piece 33 may be configured to be linearly driven including the vertical direction and the horizontal direction.

As described above, each laser beam irradiated and focused through each electrode 10 inserted and drawn between the internal lattice of the support lattice 3 is the inner lattice 5a of the support lattice 3 as shown in FIG. 8. By laser welding each of the mutually opposing side surfaces of 5b) at the same time, the best penetration can be obtained, and the welding strength between the internal lattice 5a, 5b of the support grid 3 can be strengthened.

Here, each electrode 10 inserted and drawn into the inner lattice 5a, 5b of the support grid 3 is continuous or intermittent (5a, 5b) between the inner lattice 5a, 5b of the support grid 3 Intermittent). That is, each electrode 10 inserted into the inner lattice 5a, 5b of the support grid 3 moves the laser beam between the inner lattice 5a, 5b from the upper direction to the lower direction or the lower direction to the upper direction. Can be irradiated continuously to weld the entire internal lattice 5a, 5b of the support grid 3, or only a predetermined portion of the internal lattice 5a, 5b of the support grid 3 can be welded by intermittently irradiating the laser. have.

At this time, the vertical movement speed of each welding rod 10 inserted into the inner lattice 5a, 5b of the support grid 3 to weld continuously or intermittently is made to be the same.

As shown in FIG. 9, each electrode 10 inserted and drawn into the inner lattice 5a and 5b of the support lattice 3 continuously shows the inner lattice 5a and 5b as shown in FIG. 9. As shown in FIG. 10, the inner lattice 5a, 5b can be welded only to a specific part intermittently, and the inner lattice 5a, 5b of the support grid 3 can be joined.

At this time, a protective gas is supplied to each of the welding rods 10 irradiated with a laser through the optical fiber 12 through the gas line 18, and the internal lattice between the internal grids of the support grid 3 is discharged by the supplied protective gas. To prevent oxidation of 5a and 5b).

As described above, the protective gas supplied through the gas line 18 not only prevents the oxidation of the inner lattice 5a and 5b of the support grid 3 during laser welding, but also the reflection mirror 17. You can also protect.

While the exemplary embodiments of the present invention have been described above by way of example, the scope of the present invention is not limited to the specific embodiments, and those skilled in the art are appropriate within the scope described in the claims of the present invention. It will be possible to change.

As described above, continuous or intermittent seam welding of the inner strap connection of the support lattice of the nuclear fuel rod enhances the structural strength of the support lattice and causes the welding material to splash after welding. Reduces spattering and thermal deformation, enables delicate welding to reduce the size of welding beads between support grids, reduces defects in the weld zone, and reduces the flow resistance of the coolant. The pressure drop can be reduced, thereby reducing the load on the coolant flow pump, and the laser avoids direct contact of the plasma and smoke generated by the weld during welding. It is possible to increase the life of the electrode by making it be inclined irradiated between the internal lattice that is the weld.

Claims (12)

delete delete delete delete delete delete A laser generator; An optical fiber 12 for transmitting the laser generated by the laser generator; One end of the optical fiber 12 has a cylindrical housing (10a) is introduced into the upper end, and the alignment lens 15 is provided in the interior of the housing (10a) to align the laser transmitted through the optical fiber 12 side by side ) And a focusing lens 16 provided below the alignment lens 15 to connect the laser beam passing through the alignment lens 15 to one point, and to one point by the focusing lens 16. The inclined surface 17a for reflecting the laser beam between the internal lattice 5a, 5b of the support grid 3, wherein the angle of the normal of the inclined surface 17a with the axis of the housing 10a is 57.5 ° to 67.5. A pair of welding rods having a reflecting mirror 17 having a range of ° and a laser passing hole 19 formed through one side of the housing 10a for the laser reflected from the reflecting mirror 17 to pass therethrough ( 10); A connection piece (11) interposed therebetween to connect the pair of electrodes (10) to each other; Control part consisting of a support piece 31 connected to the central portion of the connecting piece 11, a moving piece 33 connected to the support piece 31, and a linear drive unit 35 connected to the moving piece 33 30; In the inter-lattice laser welding device (1) of the nuclear fuel rod support grid comprising a, Nuclear fuel rods characterized in that the two laser through-holes 19 provided in the pair of welding rods 10 are disposed to face each other so as to simultaneously weld each of the opposite sides between the inner lattice of the support lattice Laser welding device between inner lattice of support grid. delete The method of claim 7, wherein The reflection mirror 17 is a laser welding device between the internal lattice of the nuclear fuel rod support grid, characterized in that made of a metal material. The method of claim 7, wherein The movable piece 33 is a laser welding device between the internal lattice of the nuclear fuel rod support grid, characterized in that the linear drive in the vertical direction. The method of claim 7, wherein The linear drive unit 35 is a laser welding device between the internal lattice of the nuclear fuel rod support grid, characterized in that the linear drive is made possible in the horizontal direction. The method of claim 7, wherein At least one gas line 18 is provided in place of the housing 10a to supply a protective gas for preventing oxidation of the support grid 3. .

Images