Spot-welding jig for spacer grid of nuclear fuel assembly

Abstract

The present invention relates to a spot-welding jig used to spot-weld a spacer grid of a nuclear fuel assembly, the spot-welding jig comprising: a base plate (110); a guide member (120) provided in parallel on the upper surface of the base plate (110); a movable plate (130) provided on the base plate (110) in a way that allows left-and-right movement by the guide member (120); a pair of spacer grid fixing parts (131) provided on the movable plate (130) to support the two end portions of a spacer grid (10); horizontal adjustment parts (140) provided on the base plate (110) to adjust the horizontal (x-axis) position of the movable plate (130); and a vertical adjustment part (150) provided on the base plate (110) to adjust the vertical (y-axis) position of the spacer grid seated on the movable plate (130).

Description

Spot welding fixture for support grid of nuclear fuel assembly

[0001] The present invention relates to a spot welding tool used for spot welding a support grid of a nuclear fuel assembly.

[0002] The support grid is a core component of the fuel assembly that, together with the nuclear fuel rods, instrumentation tubes, and guide tubes, fixes and supports the uranium-loaded fuel rods at regular intervals and improves heat transfer from the reactor to the coolant.

[0003] Typically, the support grid is manufactured in a grid form by arranging multiple grid plates horizontally and vertically, and each grid plate has a slot-like cut-out formed therein. The grid plates are assembled by interlocking the cut-outs in the longitudinal and transverse directions, and then spot welding the outer grid plate.

[0004] Meanwhile, if the support grid is pre-assembled before welding, clearance may occur at the cutouts in the grid, preventing welding from occurring at the correct assembly location. Once loaded into the reactor, the nuclear fuel assembly must be durable enough to withstand extreme conditions over long periods of time, requiring extremely stringent quality control during the skeleton assembly process.

[0005] The support grid can generally be composed of an inner grid plate and an outer grid plate, and the material and detailed shape of the grid plate vary depending on the design of the nuclear fuel assembly and the location of the support grid (upper / middle / lower, etc.).

[0006] Figure 1 is a perspective view of the support grid of a nuclear fuel assembly, and Figure 2 is a plan view of the support grid of a nuclear fuel assembly, showing the upper and lower support grids of HIPER16.

[0007] Referring to FIGS. 1 and 2, in the support grid (10), each outer grid plate (11-14) has an "L" shape, for example, the outer grid plates (12a) (12b) are composed of a main outer grid plate (12a) and a folded outer grid plate (12b) that is extended by being folded from the main outer grid plate (21a), and the folded outer grid plate (12b) is spot welded (W) with another main outer grid plate (11a). Accordingly, the outer grid plates (11-14) are spot welded at the "L"-shaped folded ends (see FIG. 2).

[0008] [Prior Art Literature]

[0009] [Patent Document]

[0010] Patent Document 1: Korean Patent Publication No. 10-2016-0061312 (Publication Date: June 8, 2016)

[0011] Patent Document 2: Korean Patent Publication No. 10-0770944 (Publication Date: October 26, 2007)

[0012] The present invention aims to provide a spot welding fixture that is effective for spot welding work of an external grid plate of an “L” type as described above in the prior art in a support grid of a nuclear fuel assembly.

[0013] In order to achieve the above object, a spot welding fixture for a nuclear fuel assembly according to the present invention comprises: a base plate; a guide member provided in parallel on an upper surface of the base plate; a movable plate provided on the base plate so as to be able to move left and right by the guide member; a pair of support grid fixing parts provided on the movable plate to support both ends of a support grid (10); a horizontal adjustment part provided on the base plate to adjust a horizontal direction (x-axis) position of the movable plate; and a vertical adjustment part provided on the base plate to adjust a vertical direction (y-axis) position of a support grid mounted on the movable plate.

[0014] Preferably, the base plate has a first recess formed in the center.

[0015] Preferably, the movable plate has a second groove formed on the upper surface where the support grid is mounted for inserting a welding electrode, and more preferably, the first groove is formed parallel to the support grid fixing portion.

[0016] Preferably, the movable plate is formed with a plurality of vertically formed through holes for positioning the guide tube and the measuring tube of the support grid.

[0017] Preferably, the horizontal adjustment unit is provided on each of the left and right sides of the movable plate, and includes a fixed bracket fixed to the base plate; an adjustment tip screw-assembled to the fixed bracket; and a first knob provided on the adjustment tip.

[0018] Preferably, the vertical adjustment unit includes a fixed member fixed to the base plate; a movable member capable of moving forward and backward with respect to the fixed member; and a second knob screwed to the fixed member for manipulating the movable member forward and backward.

[0019] More preferably, the invention further includes a guide shaft provided between the fixed member and the movable member to guide forward and backward movement of the movable member.

[0020] A spot welding fixture for a support grid of a nuclear fuel assembly according to the present invention comprises: a base plate; a guide member provided in parallel to an upper surface of the base plate; a movable plate provided on the base plate so as to be movable left and right by the guide member; a pair of support grid fixing parts provided on the movable plate to support both ends of a support grid (10); a horizontal adjustment part provided on the base plate to adjust a horizontal direction (x-axis) position of the movable plate; and a vertical adjustment part provided on the base plate to adjust a vertical direction (y-axis) position of the support grid mounted on the movable plate, thereby having the effect of easily and conveniently performing spot welding of an L-type external grid plate.

[0021] Figure 1 is a perspective view of the support grid of a nuclear fuel assembly.

[0022] Figure 2 is a plan view of the support grid of a nuclear fuel assembly.

[0023] Fig. 3 is a perspective view of a spot welding fixture for a support grid according to an embodiment of the present invention.

[0024] Fig. 4 is an exploded perspective view of a spot welding fixture for a support grid according to an embodiment of the present invention.

[0025] Figure 5 is a plan view of a spot welding fixture for a support grid according to an embodiment of the present invention.

[0026] Figures 6 (a) and (b) are plan views illustrating an example of use of a spot welding fixture for a support grid according to an embodiment of the present invention.

[0027] The specific structural and functional descriptions presented in the embodiments of the present invention are merely illustrative for the purpose of explaining embodiments according to the concept of the present invention, and embodiments according to the concept of the present invention may be implemented in various forms. Furthermore, they should not be construed as being limited to the embodiments described herein, but should be understood to include all modifications, equivalents, and substitutes included within the spirit and technical scope of the present invention.

[0028] Meanwhile, the terminology used in this specification is only used to describe specific embodiments and is not intended to limit the present invention. The singular expression includes the plural expression unless the context clearly indicates otherwise. It should be understood that the terms "comprises" or "has" in this specification are intended to specify the presence of implemented features, numbers, steps, operations, components, parts, or combinations thereof, but do not exclude in advance the possibility of the presence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

[0029] Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings.

[0030] FIG. 3 is a perspective view of a spot welding fixture for a support grid according to an embodiment of the present invention, FIG. 4 is an exploded perspective view of a spot welding fixture for a support grid according to an embodiment of the present invention, and FIG. 5 is a plan view of a spot welding fixture for a support grid according to an embodiment of the present invention.

[0031] Referring to FIGS. 3 to 5, a grid spot welding fixture (100) according to an embodiment of the present invention includes a base plate (110), a guide member (120), a movable plate (130), a grid fixing member (131), a horizontal adjustment member (140), and a vertical adjustment member (150).

[0032] The base plate (110) is a plate-shaped member, and a movable plate (130) is provided on the upper portion of the base plate (110) so as to be able to slide left and right (x-axis) via a guide member (120). The guide member (120) includes a guide rail (121) and a guide block (122) that can move along the guide rail (121) and is assembled with the back surface of the movable plate (130). In the present embodiment, the guide member (120) is composed of two pieces and is arranged parallel to each other. Preferably, the base plate (110) is provided with a first groove (111) formed in the center so that interference does not occur between the base plate (110) and the welding electrode during welding.

[0033] The movable plate (130) is a member on which the support grid (10) is fixed, and a pair of support grid fixing parts (131) are provided to support both ends of the support grid (10), and the interval between the two support grid fixing parts (131) approximately corresponds to the length of the support grid. Preferably, the movable plate (130) is formed with a second groove (132) for inserting a welding electrode, and the second groove (132) is formed parallel to the support grid fixing part (131). Preferably, the movable plate (130) is formed with a plurality of through holes (133) formed vertically so that the guide tube and the measuring tube of the support grid can be respectively positioned.

[0034] The horizontal adjustment unit (140) is provided on the base plate (110) to adjust the horizontal direction (x-axis) position of the movable plate (130), and is provided on each of the left and right sides of the movable plate (130). The horizontal adjustment unit (140) includes a fixed bracket (141) fixed to the base plate (110), an adjustment tip (142) screw-assembled to the fixed bracket (141), and a first knob (143) provided at the end of the adjustment tip (142). By operating the forward / reverse rotation of the first knob (143), the adjustment tip (142) moves forward and backward, thereby allowing for fine adjustment of the horizontal direction (x-axis) position of the movable plate (130).

[0035] The vertical adjustment unit (150) is provided on the base plate (110) to adjust the vertical direction (y-axis) position of the support grid (10) mounted on the movable plate (130), and includes a fixed member (151) fixed to the base plate (110), a movable member (152) arranged parallel to the fixed member (151) and capable of moving forward and backward with respect to the fixed member (151), and a second knob (153) screw-fastened to the fixed member (151) to operate the movable member (152) forward and backward. Preferably, a plurality of guide shafts (154) are provided between the fixed member (151) and the movable member (152), and the guide shafts (154) serve to guide the movable member (152) so that the movable member (152) can smoothly move forward and backward in the vertical direction (y-axis) parallel to the fixed member (151) when moving forward and backward in the vertical direction (y-axis). In this embodiment, the second knob (153) is positioned in the center of the movable member (152), and guide shafts (154) are provided on the left and right sides of the second knob (153).

[0036] Figures 6 (a) and (b) are plan views illustrating an example of use of a spot welding fixture for a support grid according to an embodiment of the present invention.

[0037] Referring to (a) of Fig. 6, after the support grid (10) is fixed on the movable plate (130), the movable plate (130) is pressed against the right side of the base plate (110), and at this time, the upper left side of the support grid (10) is positioned adjacent to the welding electrode (20). Thereafter, by operating the first knob (143') on the right, the corresponding adjustment tip (142') pushes the support grid fixing part (131') on the right side, so that the horizontal direction (x-axis) position of the movable plate (130) can be finely adjusted, and by operating the second knob (153) and moving the movable member (152) up and down, the vertical direction (y-axis) position of the support grid (10) can be finely adjusted. By this process, spot welding of the outer grid plate (A) on the upper left side of the support grid (10) can be performed.

[0038] Next, as illustrated in (b) of Fig. 6, after the movable plate (130) is pressed against the left side of the base plate (110), the horizontal and vertical positions of the support grid (10) are finely adjusted by operating the first knob (143'') and second knob (153) on the left side, and then spot welding of the outer grid plate (B) at the upper right side of the support grid (10) can be performed. By this process, spot welding is performed on four positions of the outer grid plate of the support grid.

[0039] The present invention described above is not limited to the above-described embodiments and the attached drawings, and it will be apparent to a person skilled in the art to which the present invention pertains that various substitutions, modifications, and changes are possible within a scope that does not depart from the technical spirit of the present invention.

[0040] [Explanation of symbols]

[0041] 110: Base plate 111: First groove

[0042] 120: Guide member 130: Movable plate

[0043] 131: Support grid fixing part 132: Second groove

[0044] 133: Through hole 140: Horizontal adjustment part

[0045] 141: Fixed bracket 142: Adjustable tip

[0046] 143: 1st knob 150: Vertical adjustment

[0047] 151: Fixed member 152: Movable member

[0048] 153: 2nd knob 153: Guide shaft

Claims

1. Base plate and; A guide member provided parallel to the upper surface of the base plate; A movable plate provided to enable left and right movement on the base plate by the above guide member; A pair of support grid fixing parts provided on the above movable plate to support both ends of the support grid (10); A horizontal adjustment unit provided on the base plate for adjusting the horizontal direction (x-axis) position of the movable plate; A support grid spot welding fixture for a nuclear fuel assembly, including a vertical adjustment unit for adjusting the vertical direction (y-axis) position of a support grid provided on the base plate and mounted on the movable plate.

2. A spot welding fixture for a support grid of a nuclear fuel assembly, characterized in that in the first paragraph, the base plate has a first groove formed in the center.

3. A spot welding fixture for a support grid of a nuclear fuel assembly, characterized in that in the first paragraph, the movable plate has a second groove formed in the upper surface on which the support grid is installed for inserting a welding electrode.

4. A support grid spot welding fixture for a nuclear fuel assembly, characterized in that in the third paragraph, the second groove is formed parallel to the support grid fixing part.

5. A spot welding fixture for a support grid of a nuclear fuel assembly, characterized in that in the first paragraph, the movable plate is formed with a plurality of vertically formed through holes so that the guide tube and the measuring tube of the support grid are positioned.

6. In the first paragraph, a horizontal adjustment unit is provided on each of the left and right sides of the movable plate, and includes a fixed bracket fixed to the base plate; an adjustment tip screw-assembled to the fixed bracket; and a first knob provided on the adjustment tip. A spot welding fixture for a support grid of a nuclear fuel assembly.

7. In the first paragraph, the vertical adjustment unit, A fixing member fixed to the above base plate; A movable member capable of moving forward and backward with respect to the above fixed member; A spot welding fixture for a support grid of a nuclear fuel assembly, the spot welding fixture including a second knob for operating the movable member forward and backward by being screwed to the fixed member.

8. A spot welding fixture for a support grid of a nuclear fuel assembly, further comprising a guide shaft provided between the fixed member and the movable member to guide forward and backward movement of the movable member in the 7th paragraph.

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