JP2000121782A - Rack for storing spent fuel and method for manufacturing such rack - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase the storage density of spent fuel assemblies by arranging long plates and short plates like a lattice such that inserting the terminals of the short plates into slits of the long plates and welding the former to the latter, integrating and combining the plates of both types with each other and constituting spaces out of them. SOLUTION: The intervals of notches of long partition plates 1 are equal to the width of short partition plates 2. The plates of both types are combined like a lattice. Lower convex parts of the short partition plates 2 that are orthogonally erected on the long partition plates 1 are inserted into lower notches 6 of the long partition plates 1. Their intersection points are welded, and the partition plates 1 and 2 of both types are integrated with weld metal 10 and 11. Other short partition plates 2 are also inserted into long partition plates 1 similarly, and their intersection points are welded. After the short partition plates 2 laid out in a row are welded to the long partition plates 1, upper convex parts 9 of the short partition plates 2 are inserted into notches 7 of the long partition plates 1 located above and the plates of both types are integrated with weld metal 12 used in welding. By the same procedure, this work is carried out one by one upward to assemble a rack. Finally, side partition plates 3 and a base plate 4 are inserted into the short partition plates 2 and are welded.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spent fuel storage facility of a nuclear power plant, which is capable of storing spent fuel assemblies at a high density with excellent shielding effect, excellent seismic resistance and improved space efficiency, and having high precision and high accuracy. The present invention relates to a high quality and inexpensive spent fuel storage rack and a method for manufacturing the same.

[0002]

2. Description of the Related Art Conventional spent fuel storage racks include:
The structure is as shown in JP-A-55-1532. That is, as shown in FIGS. 7 to 9, a plurality of square pipes 23 are arranged at equal intervals, and
In order to improve the earthquake resistance, a reinforcing member 27 or an earthquake-resistant reinforcing member 25 is attached to a side surface between the square pipes 23 existing at the outermost periphery by welding.

In this structure, since the spacers 24 are provided between the square pipes 23 and connected to each other, the distance between the fuel assemblies is large, so that the space efficiency is reduced.

Further, since the two side walls of the square pipe 23 exist between the fuel assemblies and the reinforcing member 27 is attached from the viewpoint of earthquake resistance, the weight of the spent fuel storage rack itself increases, and the building However, there is a problem that the load is large.

As a method for solving this problem, Japanese Patent Laid-Open Publication No.
There is a technique described in Japanese Patent Publication No. 296. In other words, by arranging a plurality of rectangular cylinders 21 in a checkered pattern as shown in FIG.
Furthermore, the space between the fuel assemblies is reduced only by the side wall of the rectangular cylinder 21, and the earthquake resistance is improved by welding a plurality of joining members 22 in the longitudinal direction of the rectangular cylinder 21.

In Japanese Unexamined Patent Publication No. 1-26991, as shown in FIG. 8, a flat horizontal plate 31 and a plurality of band-shaped vertical plates 32 are alternately laminated in a plurality of stages to form a lattice. ing.

In this method, a projection 33 formed on a strip-shaped vertical plate and a groove 34 formed on a flat horizontal plate are combined, and both corners of the combined portion are lightly fillet-welded with short leg lengths. 3
5 adhered.

[0008]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
In the publication, the distance 21a between the outer wall surfaces of the rectangular cylinders 21 arranged in a checkerboard pattern needs to be arranged so as to be substantially equal to the distance 21b between the inner wall surfaces of the rectangular cylinders 21. 21 and the radius of curvature of the two corner portions and the joining member 22
Is used to control the distances 21a and 21b between the two surfaces, but it is difficult to obtain the accuracy of the distance between the two surfaces because of the radius of curvature. In addition, since it is difficult to manufacture the rectangular cylinder 21 itself with high accuracy, it is necessary to use a slightly larger rectangular cylinder 21 having a sufficient dimension. Square cylinder 21
Are provided at a plurality of positions in the longitudinal direction, but they are welded in a narrow portion of a corner portion and lack reliability. Further, since the main welding is provided with earthquake resistance, the amount of metal deposited in the fillet welding increases, and the deformation of the rack itself increases. In addition, at the corners of the adjacent square cylinders 21 where there is no joining member 22, a gap is formed between the square cylinders 21, and the shielding effect between the fuel assemblies is reduced.

In Japanese Patent Application Laid-Open No. 1-26991, the combination of the projection 33 and the groove 34 is very small, so that the earthquake resistance is weak and the processing of the projection 33 and the groove 34 takes time. Furthermore, since the fillet weld 35 is formed on both the upper and lower surfaces of the horizontal plate 31, automatic welding is impossible.

In order to solve the above-mentioned problems, the present invention compensates for the above-mentioned drawbacks in the prior art, and has excellent seismic resistance and shielding effect by combining a plurality of partition plates in a lattice form, improving space efficiency and increasing precision. Another object of the present invention is to provide a high quality and low cost spent fuel storage rack easily.

That is, the conditions required for the spent fuel storage rack are as follows.

The spent fuel storage rack is installed in a fuel pool (not shown) filled with cooling water, and a spent fuel assembly is inserted and stored in a partitioned space provided in the rack. ing.

[0013] It is necessary to prevent re-criticality of the spent fuel assembly due to the existence of a gap between the spent fuel assemblies, which is filled with side walls (neutron shielding walls) and cooling water as a moderator. (Shielding effect).

Further, it is necessary to increase the fuel storage efficiency in the fuel pool by minimizing the distance between the spent fuel assemblies and reducing the outer dimensions of the entire rack to increase the space efficiency.

In order to reduce the distance between the spent fuel assemblies, it is necessary to improve the dimensional accuracy of the fuel storage rack.

Structurally, a structure excellent in earthquake resistance is required, and it is necessary to further reduce the weight and the load on the building.

[0017]

In order to achieve the above object, in a spent fuel storage rack in which partition plates are combined in a grid pattern, the distance between surfaces of the partition plates is determined by machining without welding. The accuracy was raised as a method of combining by intersection. Since the partition plate is integrated by a combination structure of the partition plates themselves without using a conventional joining member, the partition plate is excellent in seismic resistance and does not require an outermost anti-seismic band in the final shape. Therefore, the outer dimensions of the rack itself can be reduced, so that the overall fuel storage efficiency can be increased, and the weight is reduced and the load on the building is reduced.

Since the partition plates are combined on the grid, the separated space into which the spent fuel assemblies are inserted is manufactured without any gaps, and the spent fuel assemblies are completely partitioned by the side walls. The shielding effect, which is the most important item of the fuel storage rack, is also sufficient.

Further, in order to improve the shielding effect, it is possible to assemble two partition plates in parallel and hold a coolant in the gap between them.

As a manufacturing procedure, assembly can be performed in order from one direction, and automatic welding can be adopted by making the welding downward, so that a high-precision, high-quality and inexpensive spent fuel storage rack can be obtained.

The cuts provided in the long partition plate are machined, while the widths and projections of the short partition plate are also machined, so that the distance between the surfaces of the partition plate can be accurately determined by combining them. Manufactured. Attachment of the long partition plate and the short partition plate is performed by plug welding of the convex part of the short partition plate inserted into the cut part provided in the long partition plate, but welding is performed because the insertion part is restricted. The deformation due to is suppressed. Further, the supply of air from the back side of the welding is cut off by plug welding, so that high-quality welding can be obtained without back sealing.

Since each member has a plug-in structure, it is excellent in seismic resistance, eliminating the need for a conventional seismic support, thereby reducing the number of components and reducing external dimensions. Storage density can be increased.

As a manufacturing procedure, assembling can be performed sequentially from one direction, and automatic welding can be performed as shown in FIG.

Conventionally, a plurality of joining members are welded in the longitudinal direction by joining a plurality of joining members in a longitudinal direction. In the present invention, since all are surrounded by the partition plate and there is no gap, the shielding effect between fuels is excellent.

Further, the shielding effect can be enhanced by assembling two partition plates in parallel and holding a coolant in the gap therebetween.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment according to the present invention will be described with reference to FIGS.

FIG. 1 is an overall perspective view of a spent fuel storage rack according to the present invention, in which a long partition plate 1 and a short partition plate 2 are combined in a lattice pattern, and the distance between the partition plates, that is, the long partition plate surface. The width of the cut portion and the width of the short partition plate 2 are set so that the distance 13a and the distance 13b between the short partition plates are substantially equal.

FIG. 2 is a bird's-eye view showing an example of the long partition plate 1 according to the present invention, which has a plurality of lower cuts 6 and upper cuts 7 in the longitudinal direction.

FIG. 3 is a bird's-eye view showing an example of the short partition plate 2 according to the present invention, which has a plurality of lower projections 8 and upper projections 9 in the longitudinal direction.

FIG. 4 shows a state in which the partition plate is being assembled in the rack manufacturing stage.

The lower notch 6 provided on the long partition plate 1
The lower convex portion 8 provided on the short partition plate 2 is inserted and assembled.
The intersections of the long partition plate 1 and the short partition plate 2 are integrated by lower welding metals 10 and 11 which are provided by welding.

The lower welding metals 10 and 11 are intermittently arranged on the left and right sides of the short partition plate 2 in order to reduce welding deformation.

The upper convex portion 9 provided on the short partition plate 2 is inserted into the upper cut portion 7 provided on the long partition plate 1, and this portion is inserted into the upper weld metal 1 provided by plug welding.
2 are integrated. The spent fuel storage rack is constructed by sequentially performing the above assembly procedure from the lower side.

Finally, the side partition plate 3 and the bottom plate 4 are inserted and welded in the same manner as the partition plate, and the support legs 5 of the rack are attached by welding to complete the spent fuel storage rack.

In the case of such a structure, the distance between the partition plates, ie, the distance 13a between the long partition plates and the distance 1 between the short partition plates 1
3b are upper and lower cuts 6, provided in the long partition plate 1.
It is determined by the distance between the upper and lower cuts 6 and 7 in the adjacent row and the width of the short partition plate 2, all of which can be machined and have high precision. Further, the upper and lower cuts 6, 7 provided on the long partition plate 1 and the upper and lower projections 9, 8 provided on the short partition plate 2 are respectively combined, and assembly can be performed in order from below. Since all welding can perform downward welding with the best workability, distortion due to welding can be minimized.

In addition, since all the constituent members are plate members, there is little space for storing and assembling parts at the time of manufacture, and work can be performed.

FIG. 5 shows an embodiment of an assembly operation state of a spent fuel storage rack according to the present invention, which can be manufactured by automation.

The structure is such that the projections 8 and 9 of the short partition plate 2 inserted into the cut portions 6 and 7 provided on the long partition plate 1 are integrated by welding metals 10, 11 and 12, and the insertion portion is formed. Has excellent seismic resistance.

Therefore, there is no need to install a special earthquake-resistant band and support. As a result, the outer dimensions of the spent fuel storage rack itself can be reduced, and the storage density can be increased in the entire storage pool space.

Further, the partition plates are assembled in a grid pattern, and there is no gap between the partition plates, so that the storage fuel is completely partitioned. Thereby, the radiation shielding effect between the respective fuels is excellent.

The shielding effect can be further enhanced by using stainless steel containing boron as a neutron absorbing material as a material of the long partition plate 1 and the short partition plate 2.

As another embodiment, the long partition plate 1 and the short partition plates 2 and 2 'have a structure in which two gaps are provided, and the cooling water holding space 29 between the long partition plates and the short partition plate 2 and 2' are provided. By holding the cooling water in the cooling water holding space 30, the radiation shielding effect between the stored fuels can be further improved. Even in the case of assembling the partition plate having the two-sheet structure, the lower cut 6, the upper cut 7, the lower convex portion 8, and the upper convex portion 9 are assembled in the same manner as described above.

[0043]

As described above, according to the present invention, a high-precision and highly reliable spent fuel storage rack can be manufactured inexpensively while increasing the overall storage density. Further, the following effects can be achieved.

(1) Since the partition plates are provided with cuts and assembled, the dimensional accuracy between the partition plates is good, and the occurrence of distortion due to welding can be suppressed.

(2) In assembly welding, downward welding is possible, automatic welding can be applied, and high-quality products can be obtained with a small number of man-hours.

(3) Since the frame plate is used, a space for storing and assembling parts at the time of manufacturing may be small.

(4) Since it is a single-piece welded structure, it has excellent seismic resistance, so that no seismic band is required, the external dimensions can be reduced, and the overall storage density can be increased.

(5) The fuel itself is separated by a partition plate, and there is no gap between adjacent fuels, so that the radiation shielding effect is excellent.

(6) It is not necessary to manufacture a rectangular cylinder which is a special manufacturing method, so that it is a simple plate material assembly structure and can be manufactured with a small number of manufacturing steps.

(7) An excellent radiation shielding effect can be obtained by installing two partition plates in parallel at equal intervals to form a double structure and holding cooling water in the gaps.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing an embodiment of an overall perspective view of a spent fuel storage rack of the present invention.

FIG. 2 is an explanatory view showing the shape of a long partition plate of a spent fuel storage rack.

FIG. 3 is an explanatory view showing a shape of a short partition plate of the spent fuel storage rack.

FIG. 4 is an explanatory view showing a procedure of assembling a partition plate.

FIG. 5 is an embodiment of an assembly operation state of a spent fuel storage rack according to the present invention.

FIG. 6 is a partial plan sectional view of a conventional spent fuel storage rack.

FIG. 7 is a partial plan sectional view of a conventional spent fuel storage rack.

FIG. 8 is a partial plan sectional view of a conventional spent fuel storage rack.

FIG. 9 is an overall perspective view of a conventional spent fuel storage rack according to an embodiment.

FIG. 10 is an overall perspective view of an embodiment of a conventional spent fuel storage rack.

FIG. 11 is an explanatory view showing an embodiment in which a partition plate has a double structure.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Long partition plate, 2 ... Short partition plate, 2 '... Double-structured short partition plate, 3 ... Side partition plate, 4 ... Bottom plate, 5 ... Rack support leg, 6 ... Lower cut, 7 ... Upper notch, 8: lower convex portion, 9: upper convex portion, 10, 11: lower weld metal, 12
... upper weld metal, 13a ... distance between long partition plates, 13b
… Distance between short partition plates, 14… Automatic welding robot, 15
... Elevating device, 21 ... Square cylindrical body, 21a ... Distance between inner wall surfaces of the square cylindrical body, 21b ... Distance between outer wall surfaces of the square cylindrical body, 22 ... Joining member, 23 ... Square pipe, 24 ... Spacer, 25 ... Seismic resistance Reinforcement member, 26: rack support leg, 27: reinforcement member, 28
... Rack support legs, 29 ... Cooling water holding space between long partition plates, 30 ... Cooling water holding space between short partition plates, 31 ... Horizontal plate, 32 ... Vertical plate, 33 ... Vertical plate Protrusions formed, 34 ... grooves formed in a flat horizontal plate, 35 ... fillet welds.

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[Procedure amendment]

[Submission date] December 21, 1999 (1999.12.
21)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Full text

[Correction method] Change

[Correction contents]

[Document Name] Statement

Patent application title: Spent fuel storage rack and method of manufacturing the same

[Claims]

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a spent fuel storage rack and a method of manufacturing the same, and more particularly, to a spent fuel storage rack suitable for being installed in a fuel pool and a method of manufacturing the same.

[0002]

2. Description of the Related Art Conventional spent fuel storage racks include:
The structure is as shown in JP-A-55-1532. That is, as shown in FIGS. 7 to 9, a plurality of square pipes 23 are arranged at equal intervals, and
In order to improve the earthquake resistance, a reinforcing member 27 or an earthquake-resistant reinforcing member 25 is attached to a side surface between the square pipes 23 existing at the outermost periphery by welding. In this structure, a spacer 24 is provided between the square pipes 23.
The space efficiency is reduced because the distance between the fuel assemblies is large by providing and connecting the fuel assemblies.

Further, since the two side walls of the square pipe 23 exist between the fuel assemblies and the reinforcing member 27 is attached from the viewpoint of earthquake resistance, the weight of the spent fuel storage rack itself becomes heavy, and the building However, there is a problem that the load is large.

As a method for solving this problem, Japanese Patent Laid-Open Publication No.
There is a technique described in Japanese Patent Publication No. 296. In other words, by arranging a plurality of rectangular cylinders 21 in a checkered pattern as shown in FIG.
Furthermore, the space between the fuel assemblies is reduced only by the side wall of the rectangular cylinder 21, and the earthquake resistance is improved by welding a plurality of joining members 22 in the longitudinal direction of the rectangular cylinder 21.

In Japanese Unexamined Patent Publication No. 1-26991, as shown in FIG. 8, a flat horizontal plate 31 and a plurality of band-shaped vertical plates 32 are alternately laminated in a plurality of stages to form a lattice. ing.

In this method, a projection 33 formed on a strip-shaped vertical plate and a groove 34 formed on a flat horizontal plate are combined, and both corners of the combined portion are lightly welded with short fillet length. 3
5 adhered.

[0007]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
In the publication, the distance 21a between the outer wall surfaces of the rectangular cylinders 21 arranged in a checkerboard pattern needs to be arranged so as to be substantially equal to the distance 21b between the inner wall surfaces of the rectangular cylinders 21. 21 and the radius of curvature of the two corner portions and the joining member 22
Is used to control the distances 21a and 21b between the two surfaces, but it is difficult to obtain the accuracy of the distance between the two surfaces because of the radius of curvature. In addition, since it is difficult to manufacture the rectangular cylinder 21 itself with high accuracy, it is necessary to make the rectangular cylinder 21 slightly larger with a margin in dimension. Square cylinder 21
Are provided at a plurality of positions in the longitudinal direction. However, since the corner portions are provided with earthquake resistance, the amount of welded metal in the fillet welding increases, and the deformation of the rack itself increases. In addition, at the corners of the adjacent square cylinders 21 where there is no joining member 22, a gap is formed between the square cylinders 21, and the shielding effect between the fuel assemblies is reduced.

In Japanese Patent Application Laid-Open No. 1-26991, since the combination of the projection 33 and the groove 34 is very small, the earthquake resistance is weak, and the processing of the projection 33 and the groove 34 takes time.

An object of the present invention is to provide a spent fuel storage rack and a method of manufacturing the same, which can reduce deformation due to welding and can increase the storage density of spent fuel assemblies in a fuel pool.

[0010]

A first aspect of the present invention for achieving the above object is as follows.
A feature of the present invention is a spent fuel storage rack which is configured by arranging partition plates in a lattice shape, and which is surrounded by the partition plates and has a plurality of spaces formed therein for accommodating one spent fuel assembly. There is a plurality of first partition plates having a width capable of arranging the plurality of spaces and having a plurality of slits penetrating therethrough, and having a width of one space between the two first partition plates. A plurality of first protrusions arranged in a longitudinal direction on a first end face, and a plurality of second protrusions arranged in a longitudinal direction on a second end face different from the first end face. A plurality of second partition plates, wherein the first protrusion is inserted into the slit of one of the first partition plates facing the first end surface of the second partition plate, and A first welded portion intermittently joined to the one first partition plate, and the second protrusion Is intermittently joined to the second partition plate while the second partition plate is inserted into the slit of the other first partition plate facing the second end face of the second partition plate. And a second welded portion.

A second feature of the present invention to achieve the above-mentioned object is that a plurality of spaces are formed by arranging partition plates in a grid pattern, and are surrounded by the partition plates and each store a single spent fuel assembly. Forming a plurality of first partition plates having a width capable of arranging a plurality of the spaces and having a plurality of slits formed therethrough; and Having the width of the space, one of the first
A plurality of second protrusions having a plurality of first protrusions arranged in a longitudinal direction on a first end face opposed to the partition plate, and being arranged in a longitudinal direction on a second end face opposed to the other first partition plate. Forming a plurality of second partition plates having protrusions; inserting the second protrusions of each of the second partition plates into the slits of the other first partition plate; (2) intermittently welding each of the second partition plates and the other first partition plate in a state where the protrusions are inserted into the slits of the other first partition plate; A step of inserting the first projection of the second partition into the slit of the one first partition; and a step of inserting the first projection into the slit of the one first partition. In this state, each of the second partition plates and one of the first partition plates are intermittently welded. And a process.

In the first invention, the first projection provided on the first end surface of the second partition plate is inserted into the slit of one of the first partition plates and provided on the second end surface of the second partition plate. Since the second protrusion is inserted into the slit of the other first partition plate,
The positioning of the second partition plate with respect to the partition plate can be easily performed.
Furthermore, since each second partition plate and the other first partition plate are intermittently welded, and each second partition plate and one of the first partition plates are intermittently welded, deformation due to welding is performed. Is reduced. The second invention produces the same effect.

In particular, since a plurality of the first and second projections exist in the longitudinal direction of the second partition plate, the positioning of the second partition plate in the longitudinal direction can be easily performed.

Further, in the first invention, the first projection is inserted into the slit of one first partition plate, and the second projection is inserted into the slit of the other first partition plate. The dimensional accuracy between one partition plate and the other first partition plate and the positioning accuracy of these first partition plates are improved, and the occurrence of distortion of the second partition plate due to welding can be significantly suppressed. In addition, since each of the first partition plates and each of the second partition plates have a welded integral structure, a conventionally required earthquake-resistant band is not required. For these reasons, the storage density of the spent fuel assemblies in the fuel pool is significantly increased.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A spent fuel storage rack according to an embodiment of the present invention will be described with reference to FIGS.

The spent fuel storage rack of this embodiment has a plurality of long partition plates 1 and a plurality of short partition plates 2. The long partition plate 1 and the short partition plate 2 are combined in a lattice pattern, and the distance between the partition plates, that is, the distance 13a between the long partition plates and the distance 13b between the short partition plates are substantially equal. This is because the interval between the cut portions (through holes) provided in the long partition plate 1 is equal to the width of the short partition plate 2.

As shown in FIG. 2, the long partition plate 1 has a plurality of lower cuts 6 and a plurality of upper cuts 7 in the longitudinal direction.
Having. The lower cuts 6 and the upper cuts 7 are alternately formed in a line. As shown in FIG. 3, the short partition plate 2 has a plurality of lower protrusions 8 in the longitudinal direction of one end surface and a plurality of upper protrusions 9 in the longitudinal direction of the other end surface.

FIG. 4 shows an intermediate stage of assembling the spent fuel storage rack of this embodiment. The lower projection 8 provided on one end surface of the short partition plate 2 is incorporated into the lower cut portion 6 of the long partition plate 1 placed in the horizontal direction. In this state, the long partition plate 1 and the short partition plate 2 are integrated by the lower welding metals 10 and 11 in which the respective intersections are welded from above. The short partition plate 2 stands upright with respect to the long partition plate 1. Lower weld metal 10, 11
In order to reduce welding deformation of the long partition plate 1 and the short partition plate 2, the left and right of the short partition plate 2 are intermittently respectively.
In particular, they are arranged in a staggered pattern. After the welding of one short partition plate 2 to the long partition plate 1 is completed, the lower convex portion 8 of another short partition plate 2 arranged in parallel with the short partition plate 2 is connected to the other of the long partition plate 1. At the intersection of the long partition plate 1 and the short partition plate 2 as described above.

After the welding of the short partitions 2 arranged in a line to the long partitions 1 is completed, the plurality of upper projections 9 of these short partitions 2 are placed above these short partitions 2. It is incorporated into a plurality of upper cut portions 7 of another long partition plate 1 to be positioned. The plurality of upper convex portions 9 of the short partition plate 2 are integrated with the other long partition plate 1 by an upper weld metal 12 which is formed by plug welding from the upper surface of the other long partition plate 1. The spent fuel storage rack is assembled by sequentially performing the above assembling procedure upward from the lower side.

Finally, the projections of the short partition plate 2 are assembled into the cut portions of the side partition plate 3 and the bottom plate 4 in the same manner as described above, and the short partition plate 2 is connected to the side partition plate 3 and the bottom plate 4. To be welded. After that, the support legs 5 of the rack are attached to the bottom plate 4 by welding to complete the spent fuel storage rack.

The use of stainless steel containing boron as a neutron absorbing material as a material of the long partition plate 1 and the short partition plate 2 can further enhance the shielding effect.

According to the structure of this embodiment, the distance between the partition plates, that is, the distance 13a between the long partition plate surfaces and the distance 13b between the short partition plate surfaces are determined by the upper and lower cuts 6 provided on the long partition plate 1. It is determined by the distance between the upper and lower cuts 6 and 7 in the adjacent row and the width of the short partition plate 2, all of which can be machined and have high precision. Further, upper and lower cuts 6 and 7 provided on the long partition plate 1 and upper and lower convex portions 9 and 8 provided on the short partition plate 2.
Are combined with each other, and the assembling can be performed in order from the bottom, and since all welding can be performed with downward welding having the best workability, distortion due to welding can be minimized.

Attachment of the long partition plate and the short partition plate is performed by plug welding of a convex portion of the short partition plate inserted into a cut portion provided on the long partition plate, but the inserted portion is restricted. As a result, deformation due to welding is suppressed. Further, the supply of air from the back side of the welding is cut off by plug welding, so that high-quality welding can be obtained without back sealing.

Further, since all the constituent members are plate members, the space for storing and assembling parts at the time of manufacture is small, and work can be performed.

FIG. 5 shows a spent fuel storage rack of this embodiment.
As shown in (1), production by automatic welding becomes possible.

The spent fuel storage rack of this embodiment has a structure in which the projections 8 and 9 of the short partition plate 2 inserted into the cut portions 6 and 7 provided in the long partition plate 1 are welded to the metal 10, respectively. 1
It is excellent in earthquake resistance because it is integrated at 1 and 12 and the insertion part is restricted. Therefore, there is no need to install special seismic bands and supports, which are provided in the conventional spent fuel storage rack. As a result, the outer dimensions of the spent fuel storage rack itself can be reduced, and the storage density of the spent fuel can be increased in the entire space of the fuel storage pool.

Further, the partition plates are assembled in a lattice shape, and there is no gap between the partition plates, so that the storage fuel is completely partitioned. Thereby, the radiation shielding effect between the respective fuels is excellent.

The spent fuel storage rack is installed in a fuel storage pool (not shown) provided in the reactor building and filled with cooling water, and an adjacent long partition plate 1 and an adjacent short partition are provided. Spent fuel assemblies are inserted and stored in the space partitioned by the plate 2. A long partition plate 1 and a short partition plate 2 are provided between adjacent spent fuel assemblies.
Since the (neutron shielding wall) and the cooling water as a moderator are present, re-criticality of the spent fuel assembly can be prevented. Further, the fuel storage efficiency in the fuel storage pool can be increased by minimizing the distance between the spent fuel assemblies and reducing the outer dimensions of the entire rack to increase the space efficiency. Further, since it is not necessary to install a seismic band and a support, the weight of the spent fuel storage rack can be reduced, and the load on the reactor building can be reduced.

As described above, according to this embodiment, a high-precision and highly reliable spent fuel storage rack can be manufactured inexpensively while increasing the overall storage density. Further, the following effects can be achieved. (1) Upper and lower cuts 6 and 7 provided in long partition plate 1
Since the upper and lower projections 9 and 8 provided on the short partition plate 2 are combined with each other and assembled, the dimensional accuracy between the partition plates is good, and the occurrence of distortion of the short partition plate 2 due to welding can be suppressed. . (2) Assembling welding can be performed by downward welding, automatic welding can be applied, and high-quality products can be obtained with a small number of steps. (3) Since a frame plate is used, a space for storing and assembling parts at the time of manufacturing may be small. (4) Since it is a single-piece welded structure, it has excellent seismic resistance, so that no seismic band is required, the external dimensions can be reduced, and the overall storage density can be increased. (5) The fuel itself is separated by a partition plate, and there is no gap between the fuel and the adjacent fuel, so that the radiation shielding effect is excellent. (6) It is not necessary to manufacture a rectangular cylindrical body, which is a special manufacturing method, and it is a simple plate material assembly structure, and can be manufactured with a small number of manufacturing steps. (7) An excellent radiation shielding effect can be obtained by installing two partition plates in parallel at equal intervals to form a double structure and holding cooling water in the gaps.

Another embodiment of the present invention will be described with reference to FIG. In this embodiment, the long partition plate 1 and the short partition plates 2, 2 '
Are arranged with two gaps between them.
The cooling water holding space 29 between the long partition plates 1 and the cooling water holding space 30 between the short partition plates 1 further retain the cooling water, thereby further improving the radiation shielding effect between the stored spent fuels. Can be Even in the case of assembling the partition plate having the two-sheet structure, the lower cut 6, the upper cut 7, the lower convex portion 8, and the upper convex portion 9 are assembled in the same manner as described above.

[0031]

According to the first and second aspects of the invention, deformation due to welding can be reduced, and the storage density of spent fuel assemblies in the fuel pool can be increased.

[Brief description of the drawings]

FIG. 1 is a perspective view of the entire configuration of a spent fuel storage rack according to a preferred embodiment of the present invention.

FIG. 2 is a configuration diagram of a long partition plate shown in FIG.

FIG. 3 is a perspective view of the short partition shown in FIG.

FIG. 4 is an explanatory view showing an assembly procedure state of the partition plate shown in FIG. 1;

FIG. 5 is an explanatory view showing an example of an assembly operation state of the spent fuel storage rack shown in FIG. 1;

FIG. 6 is a partial plan sectional view of a conventional spent fuel storage rack.

FIG. 7 is a partial plan sectional view of another conventional spent fuel storage rack.

FIG. 8 is a partial plan sectional view of another conventional spent fuel storage rack.

FIG. 9 is an overall perspective view of a conventional spent fuel storage rack according to an embodiment.

FIG. 10 is an overall perspective view of an embodiment of a conventional spent fuel storage rack.

FIG. 11 is a perspective view of a spent fuel storage rack according to another embodiment of the present invention in which the partition plate has a double structure.

[Description of Signs] 1 ... Long partition plate, 2 ... Short partition plate, 2 '... Short partition plate with double structure, 3 ... Side partition plate, 4 ... Bottom plate, 5 ... Rack support leg, 6 ... Lower notch, 7 ... upper notch, 8 ... lower protrusion, 9 ... upper protrusion, 10 ... lower welded metal, 11 ... lower welded metal, 12 ... upper welded metal, 13 a ... distance between long partition plates, 13 b ... Distance between short partition plates, 14: Automatic welding robot, 15: Lifting device, 21: Square cylinder, 21a: Distance between inner wall surfaces of square cylinder, 21b: Distance between outer walls of square cylinder,
22 joining member, 23 square pipe, 24 spacer, 2
5: Reinforcement member for earthquake resistance, 26: Support leg of rack, 27: Reinforcement member, 28: Support leg of rack, 29: Cooling water holding space between long partition plates, 30: Cooling water holding space between short partition plates Reference numeral 31 denotes a flat horizontal plate, 32 denotes a vertical band plate, 33 denotes a projection formed on the vertical vertical plate, 34 denotes a groove formed on the horizontal horizontal plate, and 35 denotes a fillet weld.

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Yasukata Tamai 3-1-1, Sachimachi, Hitachi-City, Ibaraki Prefecture Inside the Hitachi Works, Hitachi, Ltd. (72) Inventor Naoto Onda 3-Chome, Sachimachi, Hitachi-City, Ibaraki Prefecture No. 1-1 Inside Hitachi, Ltd.Hitachi Plant (72) Inventor Masahiro Kobayashi 3-1-1 Kochicho, Hitachi City, Ibaraki Prefecture Inside Hitachi, Ltd.Hitachi Plant (72) Inventor Tateo Takayama Hitachi City, Ibaraki Prefecture 3-2-2, Sachimachi Hitachi New Clear Engineering Co., Ltd. (72) Inventor Yoshio Yada 3-1-1, Sachimachi, Hitachi, Ibaraki Pref. Hitachi, Ltd. Hitachi, Ltd.

Claims (4)

[Claims] 1. A spent fuel storage rack in which a plurality of cuts are provided in a long partition plate, and a plurality of cuts are provided in the long partition plate, and the long partition plate is provided with a convex portion capable of being inserted into the cut. A spent fuel storage rack, wherein a partition plate and a partition plate are combined in a grid pattern and their intersections are integrated. 2. A method for manufacturing a spent fuel storage rack comprising a combination of partition plates in a grid pattern, wherein a long partition plate is placed horizontally, a cut portion is provided in the long partition plate, and a short portion is provided in the cut portion. A plurality of the short partition plates are vertically inserted by inserting into the projections of the partition plate, and their intersections are welded downward, and another long partition plate is attached to the other projection of the plurality of short partition plates. A method for manufacturing a spent fuel storage rack, comprising combining notches, plug-welding the notches downward, and repeating the plug welding procedure. 3. The method for manufacturing a spent fuel storage rack according to claim 2, wherein the notched portion and the projected portion of the partition plate are inserted and then fixed by welding to be provided on the spent fuel storage rack. A method for manufacturing a spent fuel storage rack, characterized in that the seismic member is removed and the four directions are surrounded by partition plates without gaps. 4. The method for manufacturing a spent fuel storage rack according to claim 2, wherein the long partition plate and the short partition plate are arranged in parallel with each other with a space between them at equal intervals.
A method for manufacturing a spent fuel storage rack, comprising: assembling a partition plate having the cuts and convex portions; and holding cooling water in a gap therebetween.