JP3139921B2 - Method and apparatus for manufacturing spent fuel storage rack - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a spent fuel storage rack for storing spent fuel assemblies taken out of a nuclear reactor in a fuel storage pool and an apparatus for manufacturing the same.

[0002]

2. Description of the Related Art Generally, in a nuclear power plant,
After the reactor has been operating for a certain period of time, until the spent fuel removed from the core is reprocessed, it is stored and stored in a spent fuel storage rack previously installed in the spent fuel pool, and cooled. Performs decay heat removal of fuel.

In recent years, there has been a demand to increase the storage capacity by effectively utilizing the space in the spent fuel pool. For this purpose, for example, a material having a large neutron absorption capacity is interposed between the stored fuels to prevent the mutual fuel from being used. Spent fuel storage that can increase denseness by reducing the distance between stored fuels while maintaining criticality, and using this material as a strength member to support the stored fuel even during an earthquake etc. Racks have been proposed.

As a typical example of such a spent fuel storage rack, a boron-added stainless steel containing boron having excellent neutron absorption capacity and having good structural strength is used.
There is known a so-called lattice plate-shaped fuel storage cell structure in which one piece of boron-added stainless steel is interposed between stored fuels.

[0005] Since these conditions are satisfied and the strength is good, there is a type in which preformed rectangular cylinders are combined in a staggered lattice shape. That is, the plan view of FIG.
As shown in a partially cut-away side view taken along the line FF of FIG. 1 and a partially enlarged plan view of FIG. 16, a spent fuel storage rack 1 of this type has a large number of square cylinders 2 arranged on a base 3. Has been established,
The base 3 on the bottom of the fuel storage pool 4 of the reactor building
Are fixed by bolts 5 and nuts 6.

The rectangular cylinder 2 has a size capable of accommodating the fuel assemblies 7 one by one, and by combining the rectangular cylinders 2 in a staggered pattern as shown in FIG. Body 2
The fuel assembly 7 is stored in the first storage cell 8 inside, and the outer surface of the four rectangular cylinders 2 or the rectangular shape formed by the outer surface of the three rectangular cylinders 2 and one closing plate 9 The fuel assembly 7 can also be stored in the second storage cell 10.

[0007] These fuel assemblies 7 are fitted and supported in seat holes 3 a on the base 3. The square tube body 2 is generally formed of a boron-added stainless steel square tube obtained by bending a plate material and welding the joint thereof, and has a bent portion 2a having a curvature at the corner.

When combining the rectangular cylinders 2 in a staggered lattice shape, as shown in FIG. 16, a flat bar 11 is sandwiched between diagonally bent portions 2a of adjacent rectangular cylinders 2 at their corners. The spent fuel storage rack 1 is formed with a large number of storage cells 8 and 9 connected in a grid pattern by being fixedly connected to each other via a weld 12.

In the spent fuel storage rack 1 in which the rectangular cylinders 2 are combined in a staggered lattice, the bent cylinders 2a have an appropriate radius and the thickness of the flat bar 11 is adjusted so that the rectangular cylinders 2 are formed. Can overlap each other.

[0010] Ultimately, the inner diameter of the first storage cell 8 and the inner diameter of the second storage cell 10 are the same, and the same spent fuel storage rack as when a grid-like storage cell is assembled with one plate material. 1 can be formed.

In manufacturing the spent fuel storage rack 1 described above, the rectangular cylinders 2 are sequentially arranged at predetermined positions at intervals corresponding to the size of the second storage cells 10 , and the second storage cells are previously stored in the second storage cells 10. The first stage assembly is performed by welding to the closing plate 9 disposed at the position of the cell 10.

Thereafter, the rectangular cylinders 2 are respectively arranged directly above the second storage cells 10 of the first-stage assembly, and a flat bar 11 is formed between the rectangular cylinder 2 and the bent portion 2a of the first-stage assembly. The rectangular cylinders 2 are connected to each other by welding 12 and assembled up to the second stage. Thereafter, the square cylinders 2 are sequentially stacked in the same procedure to manufacture the spent fuel storage rack 1.

In this case, a crane is used to transport the rectangular cylindrical body 2 and the like, and after the rectangular cylindrical body 2 is set on a positioning jig manually by an operator in order to position the rectangular cylindrical body 2 at a predetermined position. The flat bar 11 having a thickness corresponding to the bent portion 2a of the rectangular cylindrical body 2 is measured and sandwiched, and temporary attachment and main welding are performed by manual welding.

However, since the rectangular cylinder 2 is formed by bending a plate material, the diagonal dimension L between the bent portions 2a is not always constant and has a large tolerance, so that the pitch between the storage cells can be accurately assembled. Therefore, it is difficult to improve the density.

As means for solving this problem, for example,
The technique disclosed in Japanese Patent Application Laid-Open No. 5-80188 is known. That is, as shown in the plan view of FIG. 17, the spent fuel storage rack 20 is formed by combining a plurality of first grid plates 21 and second grid plates 22 in a grid shape, fitting and fixing them together, and forming a plurality of squares. The juxtaposed fuel storage cells 23 are formed.

The spent fuel storage rack 20 is provided with bolts and nuts (not shown) on the bottom of a fuel storage pool (not shown).
The plurality of fuel assemblies 7 are individually inserted into the fuel storage cells 23 and fitted and supported in seat holes (not shown) on the base 3.

Further, an enlarged vertical sectional view taken along the line GG of FIG. 17 of FIG. 18, a sectional view taken along the line HH of FIG. 19 of FIG. FIG. 21 is a sectional view taken along the line I;
As shown in the perspective view of FIG. 1, the first lattice plate 21 has a length corresponding to the axial length of the fuel assembly 7 and a width corresponding to the width of one fuel storage cell 23, and extends along one end surface thereof. A plurality of protrusions 24 are provided, and a concave portion 25 fitted to the protrusion 24 of the adjacent first lattice plate 21 is provided on the opposite end surface.
Are formed.

On the other hand, the second grid plate 22 has a length corresponding to the axial length of the fuel and a width corresponding to the width of the spent fuel storage rack 20 in which a plurality of fuel storage cells 23 are juxtaposed. Yes,
A plurality of slits 26 into which the projections 24 of the first grid plate 21 are inserted are formed at a pitch corresponding to one fuel storage cell 23.

The plurality of first grid plates 21 and the second grid plates 22 are arranged so as to intersect at right angles with each other on the plane of the spent fuel storage rack 20, and the slits 26 of the second grid plates 22 are formed.
The projection 24 of the first lattice plate 21 is inserted into the first lattice plate 21, and the recess 25 of the other first lattice plate 21 adjacent to the projection 24 of the first lattice plate 21 protruding from the second lattice plate 22 is fitted. The first lattice plate 21 and the first lattice plate 21 and the second lattice plate
22 are welded 27 so as to be firmly connected to each other to form a plurality of juxtaposed fuel storage cells 23.

In manufacturing the spent fuel storage rack 20, a slit 26 is formed in one second lattice plate 22.
A plurality of first lattice plates 21 are disposed at right angles so that the recesses 25 face each other with respect to the position, and the end side surface of the contacted first lattice plate 21 and the second lattice plate 22 are connected to each other. It is fixed by welding 27 and the first-stage assembly is performed.

Next, the projections of the first lattice plate 21 of the first stage
The second lattice plate 22 is placed on the second lattice plate 22 so that the slit 26 of the second lattice plate 22 on the second lattice plate 24 is located on the second lattice plate 22 of the second stage. , And the projection 24 is projected from the slit 26.

Thereafter, the first grid plate 21 of the second stage is disposed so that the recess 25 thereof is fitted with the projection 24 protruding from the slit 26, and the first grid plate 21 of the first stage is welded 27. The 21 projections 24 are connected to the second-stage second lattice plate 22 and the second-stage first lattice plate 21. Thereafter, in the same procedure, the spent fuel storage rack 20 is manufactured by sequentially stacking the second grid plate 22 and the first grid plate 21.

In this case, a crane is used to transport the second grid plate 22 and the first grid plate 21, and the positioning of each grid plate and the insertion of the projections 24 and the slits 26 are performed by a worker. It depends on the work, and the tacking and main welding are also manual welding.

[0024] Since the pitch between storage cells as described above is determined by machining accuracy, assembly is easy, highly accurate, it is possible to produce a spent fuel storage rack with improved compactness .

[0025]

In assembling a conventional spent fuel storage rack in which preformed rectangular cylinders are combined in a staggered lattice, flat bars 11 are formed at the corners of the rectangular cylinder 2.
The rectangular cylinders 2 are fixed to each other by welding 12 via the through hole. The rectangular cylinder 2 is formed by bending a plate material as described above.

The corner portion has a bent portion 2a having a curvature, and the diagonal dimension L of the bent portion 2a is not always constant and has a large tolerance. Therefore, when assembling with the flat bar 11 interposed between the bent portions 2a on the diagonal line of the rectangular cylindrical body 2, the four rectangular cylindrical bodies 2 are required to reduce the storage pitch.
The inner diameter of the rectangular second storage cell 10 formed on the outer surface of the fuel cell 7 is the same as the inner diameter of the first storage cell 8 in the prismatic body 2, and the subcriticality of the fuel assembly 7 is maintained.

Therefore, it is extremely difficult to accurately assemble the pitch between the storage cells to the required value, and to manufacture the pitch between the fuel storage cells within a certain range with high precision, it is very difficult. There is a problem that the number of assembling steps required for confirmation and the like is large and the economic efficiency is poor.

Japanese Unexamined Patent Application Publication No. Hei 9 (1994) -1992 has been proposed to solve the above problems.
In Japanese Patent Application Laid-Open No. 5-80188, the combination of a flat plate-shaped second grid plate 22 and a plurality of strip-shaped first grid plates 21 is formed by the first grid plate 21 protruding from a slit 26 of the second grid plate 22. Is limited to the projection 24, so that only a fraction of the total height of the grid plate can be fixed.
There is a problem that the rigidity of the connection between the lattice plates is weak, and the seismic resistance is poor.

In addition, machining the projections 24 and the recesses 25 of the first lattice plate 21 and the slits 26 of the second lattice plate 22 to a fraction of the total height requires only a small number of processing steps. There is also the disadvantage of increasing.

Further, as a similar example, see, for example,
A technique disclosed in Japanese Patent Application Laid-Open No. 5-80188 discloses a technique disclosed in Japanese Patent Application Laid-Open No. 5-80188, in which the connection between a flat grid plate and a strip grid plate is performed by connecting a flat grid plate to a slit formed in the flat grid plate. After plugging in the same way as above, plug welding is performed. Also in this case, for the same reason as in Japanese Patent Application Laid-Open No. 5-80188, there is a problem that the number of processes increases due to poor seismic resistance.

On the other hand, in the manufacture of the above two types of spent fuel storage racks, a square cylinder or a grid plate is sequentially removed by one worker.
The process of stacking step by step and performing temporary fixing and main welding is adopted.For the transfer of the rectangular cylinder or the grid plate, use a crane and set the positioning jig manually by the operator, and The welding was also manual welding by workers. For this reason, the number of assembling steps is increased, the production period is long, and there is a problem that the production must depend on the skill of the worker.

The present invention has been made in order to solve the above-mentioned problems. In order to improve the density by combining a plurality of grid plates with high accuracy, it is required that the intersection of each grid plate from the inside of the storage cell be strengthened. A method for manufacturing a high-quality, inexpensive spent fuel storage rack with excellent seismic resistance by welding an appropriate amount of fuel, and assembling the spent fuel storage rack with automation and stable quality without skilled workers It is another object of the present invention to provide a manufacturing apparatus suitable for performing the manufacturing method .

[0033]

Means for Solving the Problems of claims 1 invention, Sri
And a flat lattice plate provided with a slot and inserted into the slit
Assembly comprising a strip-shaped grid plate provided with projections
Equipped with a plurality of fuel storage cells
In the manufacturing method of spent fuel storage racks, the plate
Insert the projection of the band-shaped grid plate into the slit of the grid-shaped grid plate
Tentatively assembling into a grid to form a plurality of the fuel storage cells
And welded to form a lattice plate temporary assembly.
The flat grid plate and the band grid plate are substantially
Tilt the welding torch to 45 ° with the corners facing down.
Characterized that you present welding plug into the charge storage cells.

According to a second aspect of the present invention, the fuel assemblies are provided one by one.
Combine multiple fuel storage cell grid plates to be stored
In the apparatus for manufacturing a spent fuel storage rack, the fuel
It is large enough to be inserted into the storage cell,
The welding torch horizontally with the arm protruding from the rear end.
A structure that can move in the axial direction and the cell grid plate serves as a guide.
So that the roller moves on the cell grid plate.
It is characterized by having been done .

According to a third aspect of the present invention, the cell grid plate is temporarily assembled.
Rotating device that rotates what it sees around its longitudinal axis
Automatically attaches the welding torch to each of the cell grid plates
Welding device for positioning, inserting and welding, and this welding device
And a control device for integrally controlling the control .

According to the first aspect of the present invention, a storage rack is constructed by combining a plurality of lattice plates of two types having predetermined dimensions and having projections and slits. Therefore, the dimensional accuracy is increased depending on the machining, and the denseness is improved. Further, since the four corners are fixed by welding from inside the storage cell by the welding torch that can be inserted into the storage cell, the entire lattice plate is rigidly connected, and as a result, the earthquake resistance is improved.

Further, the reliability of the welded portion is improved by welding the grid plate intersection at the corner of the storage cell downward. At the same time, since the welding torch can be moved by using the V-shaped groove at the intersection of the lattice plates as a guide, the positioning of the welding torch with respect to the welding line is facilitated and automation is facilitated.

The spent fuel storage rack after the temporary assembly is rotated about the longitudinal axis, and the rack is assembled by using a manufacturing apparatus having a mechanism for moving and positioning the welding torch and a mechanism for controlling these. Thus, a high-quality rack can be manufactured without depending on the skill of the worker.

With the above-mentioned components and functions, a spent fuel storage rack having improved dimensional accuracy and improved denseness, increased rigidity and improved seismic resistance can be easily and easily shortened by highly reliable automatic welding. It can be manufactured with a delivery date and without depending on the skill of the worker.

[0040]

Spent fuel storage rack according to the embodiment of the present invention
An embodiment of a method for manufacturing a metal will be described . Note that the same components as those of the above-described conventional technology are denoted by the same reference numerals, and detailed description thereof will be omitted.

As shown in the plan view of FIG. 1 and the enlarged vertical cross-sectional view taken along the line AA of FIG. 1, the spent fuel storage rack 30 includes a plurality of flat grid plates 31 and a band shape. The lattice plates 32 are combined in a lattice shape, and are fitted and fixed to each other to form a plurality of square-shaped fuel storage cells 33 arranged side by side.

The spent fuel storage rack 30 is mounted on a base 3 fixed to the bottom of a fuel storage pool (not shown) by bolts and nuts (not shown), and a plurality of fuel assemblies 7 It is individually inserted into the storage cell 33 and is fitted and supported in a seat hole (not shown) on the base 3.

Further, as shown in the sectional view taken along the line BB of FIG. 3, the sectional view taken along the line CC of FIG. 2, and the perspective view for explaining the lattice plate combination shown in FIG. The band-shaped lattice plate 32 has a length corresponding to the axial length of the fuel assembly 7 and a fuel storage cell 33.
A plurality of projections 35 are provided along both end faces of the projection 35. The projection height of the projection 35 is set at one end face and at the opposite end face. Are formed at positions different from each other.

On the other hand, the flat lattice plate 31 has a length corresponding to the axial length of the fuel assembly 7 and a width corresponding to the width of the spent fuel storage rack 30 in which the plurality of fuel storage cells 33 are juxtaposed. A plurality of slits 34 into which the projections 35 of the band-shaped lattice plate 32 are inserted are formed at a pitch of one fuel storage cell 33. Further, the height of the projection 35 of the band-shaped lattice plate 32 is set slightly smaller than the thickness of the plate-shaped lattice plate 31.

The plurality of flat grid plates 31 and the strip grid plates 32 are arranged so as to intersect at right angles with each other on the plane of the spent fuel storage rack 30, and are formed in slits 34 of the flat grid plate 31.
After inserting the projection 35 of the band-shaped grid plate 32,
31 and the strip-shaped lattice plate 32 are firmly connected to each other by welding 36.

Thus, a plurality of fuel storage cells arranged side by side
33 is formed, in this case, the welding 36 is performed from within the storage cell 33 and is performed at four corners thereof. Hitting the formation of the fuel storage cells 33, at both end faces projections 35 of the belt-like grid plate 32, to position the uneven height different from each other, arranged a strip grid plate 32 on both sides of the flat lattice plate 31 And its projection 35
Can be inserted into the slits 34 having different heights of the flat lattice plate 31 without interfering with each other.

Since the height of the projection 35 of the band-shaped lattice plate 32 is set slightly smaller than the thickness of the plate-shaped lattice plate 31, the projection 35 is inserted into the slit 34 of the plate-shaped lattice plate 31. In this case, the end face of the next strip-shaped lattice plate 32 coming to this surface without sticking out from the opposite surface of the plate-shaped lattice plate 31 can be brought into close contact with the surface of the plate-shaped lattice plate 31.

According to this structure, it is possible to assemble the pitch between the fuel storage cells with high accuracy and improve the denseness, and to firmly connect the respective lattice plates into a cruciform joint by welding.
It can sufficiently withstand vibration during an earthquake, and can safely and reliably store a large number of fuel assemblies 7.

The welding 36 may be performed continuously over the entire length of the flat grid plate 31 and the strip grid plate 32 in the longitudinal direction, or when the load applied to the weld 36 is small due to strict seismic requirements. May be intermittent welding. In this case, the number of steps required for welding can be reduced, and shortening of the work period can be expected.

The projections 35 of the band-shaped lattice plate 32 are not involved in the welding connection between the lattice plates, but are inserted into the slits 34 of the plate-shaped lattice plate 31 only for positioning each other. It is sufficient if the slit 34 and the projection 35 have several places over the entire height. In this respect, the number of machining steps can be reduced and the manufacturing process can be expected to be shortened.

As another embodiment, as shown in the perspective view of FIG. 6, instead of the slits and the projections, the third band-like lattice plate 39 may be provided with pins 40 and the flat lattice plate 31 may be provided with holes 41. good. In this case, the pins 40 do not necessarily need to be integrally cut from the third band-shaped lattice plate 39, and can be attached by appropriate means such as welding.

Accordingly, the number of processing steps can be reduced as compared with the band-shaped lattice plate 32 (see FIG. 5) for integrally shaping the projection 35.
In addition, materials can be saved. In addition, the flat lattice plate 31 has holes.
41 can also be machined by drilling and the slit 34 shown in FIG.
It can reduce the number of processing steps.

Meanwhile, the projections of the strip grid plate does not necessarily need to be placed in uneven heights that differ from one another at both end faces. For example, as shown in FIG. 7, the protrusion 35 of the first band-shaped lattice plate 37 located on the left side of the plate-shaped lattice plate 31 is placed upward, and the protrusion 35 of the second band-shaped lattice plate 38 located on the right side is placed first. The height may be different from that of the projection 35 of the band-shaped lattice plate 37, and may be located at the same level in the same lattice plate.

Further, if the height of the projections 35 is set slightly smaller than の of the thickness of the flat grid plate 31, the height of the projections 35 is changed for each strip grid plate as shown in FIG. There is no need to insert them into the same slit 34 of the flat lattice plate 31 without interfering with each other. In this case, the number of the slits 34 of the flat lattice plate 31 can be reduced by half, and the time required for processing can be further reduced.

Spent fuel storage rack according to the present embodiment
According to the production method of
Weld by inserting the protrusion of the slave plate, so the insertion part supports
This makes it easier to temporarily assemble and weld the grid plate.
You. In addition, after the temporary assembly, the entire lattice
Angle, with the corners facing down,
The advantage is that contact can be made securely and in a short time .

Next, an embodiment of the apparatus for manufacturing a spent fuel storage rack according to the present invention will be described. First, FIG.
As shown in the perspective view of the lattice plate combination of FIG.
The projections 35 of the band-shaped grid plate 32 are inserted into the slits 34, and the fuel storage cells 33 are sequentially formed. According to this embodiment, a grid plate temporary assembly of 9 rows × 9 columns as shown in the plan view of FIG. Produce 42.

FIG. 8 is a detailed view of the welding torch, and FIG.
FIG. 10 is an overall view of the manufacturing apparatus, and FIG.
FIG. 11 is a view taken along line EE in FIG. 10, and thereafter FIGS.
The main welding will be performed by each device shown in FIG.

That is, the manufacturing equipment for the spent fuel storage rack
In FIG. 8, the welding torch 50 and the welding torch
Rollers 51 for supporting the own weight are provided before and after 50 , and a drive arm 52 for driving the welding torch 50 in a horizontal direction protrudes from a rear end thereof. As shown in FIG. 9, the V-shaped groove formed by the flat grid plate 31 and the band grid plate 32 of the fuel storage cell 33 allows
The roller 51 and the welding torch 50 can move freely in the vertical and horizontal directions with respect to the drive arm 52 so that the welding torch 50 is guided and set at a predetermined position with high accuracy via the roller 51. Has become.

As shown in FIG . 10 and FIG.
Has a structure capable of holding the lattice plate temporary assembly 42 and rotating the lattice plate temporary assembly 42 around its longitudinal axis. The control device 55 can position the lattice plate temporary assembly 42 in a predetermined direction and angle.

The welding torch moving mechanism 53 includes a drive arm 52
After the welding torch 50 is moved in the horizontal and vertical directions through the positioning of the welding torch 50 to the predetermined fuel storage cell 33, the drive arm 52 is driven to insert the welding torch 50 into the fuel storage cell 33 and perform welding. These operations are also controlled by the controller 55.

The rotating device 54 and the welding torch moving mechanism 53
Are controlled by one control device 55 and are operated in cooperation with each other. In assembling, the lattice plate temporary assembly 42 is set on a rotating device 54 that can hold and rotate the lattice plate temporary assembly 42 about the longitudinal axis of the lattice plate temporary assembly 42.

This rotating device 54 tilts the grid plate temporary assembly 42 by 45 ° from the horizontal so that the corners of the fuel storage cells 33 formed by the flat grid plate 31 and the strip grid plate 32 are formed as shown in FIG. The welding torch 50 is inserted into the fuel storage cell 33 and the welding 36 is performed.

In this case, the welding torch 50 has its own weight supported by rollers 51 attached to the front and rear thereof, and is driven in the horizontal direction by a driving arm 52 protruding from the rear end. Also,
In the welding of the inner corner of the storage cell 33, the flat lattice plate 31
Then, the V-shaped groove formed by the band-shaped lattice plate 32 serves as a guide for the roller 51, so that the welding torch 50 can be accurately positioned with respect to a predetermined welding portion.

Next, a series of working steps will be described. First, the grid plate temporary assembly 42 is set on the rotating device 54, and the rotating device 54 is rotated by the control device 55 in a predetermined direction and angle to temporarily set the grid plate temporary assembly. After the body 42 is positioned at a predetermined position, the welding torch moving mechanism 53 moves the welding torch 50 in the horizontal and vertical directions to position it at a predetermined fuel storage cell 33 of the lattice plate temporary assembly 42, and is inserted by the drive arm 52. Then, welding 34 is performed by the welding torch 50.

This series of welding torch moving mechanism 53, drive arm
The movement of 52 and welding by the welding torch 50 are also controlled by the control device 55, and are performed in a series of operations as a predetermined procedure, and the necessary welding 36 is completed in sequence according to a predetermined procedure. Thereafter, as shown in FIG. 1, the base 3 is attached to the lattice plate temporary assembly 42 on which all necessary welding 36 has been completed, and the assembly of the spent fuel storage rack 30 is completed.

As described above, the welding torch 50 can be automatically positioned by the rotating device 54, the welding torch moving mechanism 53 and the control device 55 to perform the welding operation. Racks can be manufactured, and the manufacturing period can be reduced by automation, and a highly reliable product can be provided by performing stable downward welding at the grid plate intersection.

As another embodiment , first, as shown in FIG. 12, the projections 35 of the plurality of band-like lattice plates 32 are inserted into the slits 34 of one plate-like lattice plate 31,
After arranging the plurality of band-shaped lattice plates 32 at right angles, welding is performed from both sides of each band-shaped lattice plate 32 to produce the single-row unit 43.

The welding 36 has a welding torch on both sides of the strip-shaped lattice plate 32 and can be moved in the entire length direction of the strip-shaped lattice plate 32, as is commonly used automatic welding equipment (not shown). By using this, the single-row unit 43 with stable quality can be manufactured in a short period of time.

Thereafter, as shown in FIG. 13, a single-row unit 43 is placed on one flat grid plate 31 such that the end face of the strip grid plate 32 is located on the lower side, and the projections 35 are formed on the flat grid plate 31. Board 31
And temporarily assemble it.

Thereafter, the one-row units 43 are sequentially stacked to assemble a lattice plate temporary assembly 42 having a predetermined size. After assembling the lattice plate temporary assembly 42, it is mounted on the rotating device 54 as described above, and welding of a portion where welding is not performed is automatically performed.

The spent fuel storage rack according to the above embodiment is
According to the manufacturing equipment of the fuel tank, a plurality of spent fuel storage racks 30
When performing the production and assembly of the grid plate provisional assembly 42, it can be performed in parallel assembly of a row unit 43
Thus, it is possible to contribute to shortening of the manufacturing period.

[0072]

The manufacturing of the spent fuel storage rack according to the present invention .
According to the manufacturing method, the strip-shaped grid plate is
The projection is inserted and welded, so the insertion
Therefore, temporary assembly welding becomes easy. Also, after temporary assembly
At this point, the entire lattice plate temporary assembly is inclined at approximately 45 degrees, and the corners are
Main welding is performed downward, so the main welding can be performed reliably and in a short time.
There is an effect that can be performed with .

Production of the spent fuel storage rack according to the present invention
According to the apparatus, the manufacturing of the spent fuel storage rack is automated by a rotating device for rotating the lattice plate temporary assembly, a moving mechanism of the welding torch, its control device, and a welding torch that can be inserted into the fuel storage cell. High-quality racks can be manufactured in a short period of time without depending on the skill of the members.

[Brief description of the drawings]

FIG. 1 shows a method for manufacturing a spent fuel storage rack according to the present invention.
FIG. 1 is a plan view showing an embodiment for explaining the embodiment .

FIG. 2 is an enlarged cross-sectional view taken along the line AA of FIG. 1;

FIG. 3 is a sectional view taken along line BB of FIG. 2;

FIG. 4 is a sectional view taken along line CC of FIG. 2;

FIG. 5 is a perspective view showing a first example of a lattice plate combination in FIG. 1;

FIG. 6 is a perspective view showing a second example of the lattice plate combination in FIG . 1 ;

FIG. 7 is a perspective view showing a third example of the lattice plate combination in FIG . 1 ;

FIG. 8 is a schematic diagram showing a welding device used in the present invention.

FIG. 9 is a front view in the direction of the arrow along the line DD in FIG. 8;

FIG. 10 is a configuration diagram showing a manufacturing apparatus of the present invention.

11 is a front view of the rotation mechanism in FIG. 10 taken along line EE.

FIG. 12 is a front view showing a single-row unit in another manufacturing example of the present invention.

FIG. 13 is an assembly view for explaining a production example in FIG. 12;

FIG. 14 is a plan view showing a conventional spent fuel storage rack.

FIG. 15 is a side view partially cut away in the direction of the arrow along the line FF in FIG. 14;

FIG. 16 is an enlarged plan view showing a main part in FIG. 14;

FIG. 17 is a plan view showing another example of the conventional spent fuel storage rack.

18 is an enlarged vertical sectional view taken along line GG of FIG. 17;

FIG. 19 is a sectional view cut along the line HH of FIG. 18;

FIG. 20 is a sectional view taken along the line II of FIG. 18;

FIG. 21 is a perspective view for explaining the grid plate assembling method in FIG. 14;

[Explanation of symbols]

Reference numeral 30 denotes a spent fuel storage rack, 31 denotes a flat grid plate, 32 denotes a band grid plate, 33 denotes a fuel storage cell, 34 denotes a slit, 35 denotes a projection, 36 denotes a weld, and 37 denotes a first band grid plate a, 38. .., A second band-shaped lattice plate, 39, a third band-shaped lattice plate, 40, a pin, 41, a hole,
42: lattice plate temporary assembly, 43: single row unit, 50: welding torch, 51: roller, 52: drive arm, 53: welding torch moving mechanism, 54: rotating device, 55: control device.

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Toshiro Kodama 2-4, Suehirocho, Tsurumi-ku, Yokohama-shi, Kanagawa Pref. JP-A-5-80189 (JP, A) JP-A-58-113795 (JP, A) JP-A-62-25297 (JP, A) JP-A-5-80188 (JP, A) (58) Int.Cl. ⁷ , DB name) G21C 19/07

Claims (3)

(57) [Claims] 1. A flat lattice plate provided with slits ,
Up of the strip-shaped grid plate provided with projections to be inserted into the slit
A plurality of fuel storage cells for storing the formed fuel assemblies are provided.
Of manufacturing a spent fuel storage rack installed on a base
In the slit of the flat grid plate, the band grid
A plurality of the fuel storage cells are formed by inserting plate protrusions.
Temporarily assembled and welded into a grid shape to form a grid plate temporary assembly.
The grid plate temporary assembly is formed by combining the flat grid plate and the band grid plate.
Incline at approximately 45 degrees to the horizontal, with the corners facing down
The method of producing a spent fuel storage rack, characterized that you present welding insert the welding torch into the fuel storage cells. 2. A manufacturing apparatus for a spent fuel storage rack comprising a combination of a plurality of fuel storage cell lattice plates accommodating one fuel assembly at a time, wherein the apparatus has a size that can be inserted into the fuel storage cell. It has a structure in which the welding torch can be moved in the horizontal axis direction with an arm protruding at the rear end, having a roller before and after the torch, and the roller is configured to move on the cell grid plate using the cell grid plate as a guide. An apparatus for manufacturing a spent fuel storage rack. 3. A rotating device for rotating the temporarily assembled cell grid plate around its longitudinal axis, and a welding device for automatically positioning and inserting and welding the welding torch to each of the cell grid plates. 3. A manufacturing apparatus for a spent fuel storage rack according to claim 2 , further comprising a control device for integrally controlling said welding device.