JP7161960B2 - Storage cell, nuclear fuel storage rack, storage cell manufacturing method, and nuclear fuel storage rack manufacturing method - Google Patents

Description

The present invention relates to a storage cell for storing nuclear fuel in an upright state in water in a storage pit, a nuclear fuel storage rack, a method for manufacturing the storage cell, and a method for manufacturing a nuclear fuel storage rack.

For example, in Patent Document 1, a neutron absorbing material (also referred to as a "neutron shielding wall") of boron is placed inside a rectangular cylindrical housing with a bottom made of steel or non-ferrous metal and having an open top. A fuel storage rack is disclosed in which a plurality of square-tube-shaped cells made of stainless steel or aluminum to which is added are arranged at equal intervals and fixed by appropriate means such as welding.

Further, in Patent Document 2, a long partition plate provided with a plurality of notches and a short partition plate provided with a convex portion that can be inserted into the notch of the long partition plate are provided, and the long partition plate and the short partition plate are provided. A nuclear fuel storage rack is disclosed in which the racks are combined in a lattice shape and the intersections are integrated.

Further, Patent Literature 3 discloses that a circular tube is formed and then formed into a square tube by extrusion roll molding or press molding.

Japanese Patent No. 5951359 Japanese Patent Application Laid-Open No. 2000-121782 JP-A-2000-227494

In the fuel storage rack described in Patent Document 1, in order to manufacture square-tube-shaped cells made of boron-added stainless steel or aluminum, circular tubes are formed from the above material as disclosed in Patent Document 3. However, it requires a labor-intensive work such as extruding the circular tube into a square tube, which is very costly.

In addition, in fuel storage racks that store nuclear fuel used in pressurized water reactors, fast neutrons are moderated to thermal neutrons to efficiently absorb neutrons and remove decay heat from spent nuclear fuel. Therefore, an area must be provided around the nuclear fuel for arranging the water in the storage pit. For example, in the fuel storage rack described in Patent Document 2, this area is formed by the gap between the inner surface of the cell or lattice and the nuclear fuel, and it is not easy to ensure the accuracy of this area.

The present invention solves the above-mentioned problems, and provides water (hereinafter referred to as "cooling storage cells, nuclear fuel storage racks, and circular tubes that can secure an area (hereinafter referred to as a "cooling area" for the sake of convenience) for disposing It is an object of the present invention to provide a method for manufacturing a storage cell that does not contain a nuclear fuel and a method for manufacturing a nuclear fuel storage rack.

To achieve the above object, a storage cell according to one aspect of the present invention includes a cell assembly comprising a plurality of small cell assemblies, the small cell assemblies comprising a pair of opposing side plates and a pair of opposing side plates. and a plurality of partition plates arranged to connect the pair of side plates, and a plurality of storage areas arranged so that nuclear fuel can be inserted by the pair of side plates facing each other and the plurality of partition plates. and a first cooling region through which cooling water can flow is formed between each of the storage regions, and the cell assemblies are arranged such that the side plates of adjacent small cell assemblies face each other. The cell assemblies are arranged side by side, and a second cooling area is formed between adjacent small cell assemblies in which cooling water can flow.

Further, in the storage cell according to the aspect of the present invention, the small cell assembly has a protruding piece in which a part of the partition plate penetrates to the outside of the side plate, and is joined as the cell assembly. It is preferable that the second cooling area is defined by the projecting piece.

Further, in the storage cell according to the aspect of the present invention, the protruding pieces are intermittently provided to penetrate the outside of the side plate, and the plurality of small cell assemblies are joined together as the cell assembly. , the projecting pieces of one of the small cell assemblies and the projecting pieces of the other small cell assembly are preferably arranged alternately.

In order to achieve the above object, a nuclear fuel storage rack according to one aspect of the present invention is mounted on the floor surface of a storage pit while supporting a plurality of the storage cells and the cell assemblies in the storage cells. The rack body includes a support member that supports the cell assemblies side by side and forms a third cooling region between the cell assemblies in which cooling water can flow. have.

Further, in the nuclear fuel storage rack according to one aspect of the present invention, the rack body has a plurality of the support members arranged in the direction in which the nuclear fuel is inserted into the storage area, and each of the support members is arranged between the cell assemblies. It is preferable to have a reinforcing member connecting the .

Further, the nuclear fuel storage rack according to one aspect of the present invention includes a positioning member disposed between the support member and the cell assembly to fix the position of the cell assembly with respect to the support member. is preferred.

A nuclear fuel storage rack according to one aspect of the present invention includes a storage cell having a storage area into which nuclear fuel is inserted, and a rack body that supports a plurality of the storage cells and is placed on the floor of a storage pit. The rack body has a plurality of support members arranged side by side to support the storage cells arranged in a direction in which the nuclear fuel is inserted into the storage area, and a reinforcing member connecting each of the support members between the storage cells. have.

In order to achieve the above object, a storage cell manufacturing method according to an aspect of the present invention includes a pair of side plates facing each other, and a plurality of partition plates arranged to connect the pair of side plates facing each other. A step of forming a plurality of small cell assemblies in which a plurality of storage areas into which nuclear fuel can be inserted are arranged side by side and a first cooling area in which cooling water can flow is formed between the storage areas; A cell set in which a plurality of small cell assemblies are arranged so that the side plates of the adjacent small cell assemblies face each other, thereby forming a second cooling region between the adjacent small cell assemblies in which cooling water can flow. and constructing a solid.

Further, in the method for manufacturing a storage cell according to an aspect of the present invention, the small cell assembly has a protruding piece that a part of the partition plate penetrates to the outside of the side plate, and through the protruding piece the Preferably, they are joined together as a cell assembly to define said second cooling zone.

Further, in the method for manufacturing a storage cell according to an aspect of the present invention, a wedge member is inserted into the protruding piece penetrating to the outside of the side plate, and a retaining member for retaining the wedge member is welded to the wedge member. is preferred.

To achieve the above object, a method for manufacturing a nuclear fuel storage rack according to one aspect of the present invention includes a pair of side plates facing each other, and a plurality of partitions arranged to connect the pair of side plates facing each other. A step of constructing a plurality of small cell assemblies in which a plurality of storage areas into which nuclear fuel can be inserted are juxtaposed by plates, and a first cooling area in which cooling water can flow is formed between the storage areas. and a plurality of the small cell assemblies are arranged so that the side plates of the adjacent small cell assemblies face each other, thereby forming a second cooling region in which cooling water can flow between the adjacent small cell assemblies. forming a plurality of cell assemblies; arranging a plurality of the cell assemblies side by side on a rack body placed on the floor of a storage pit; and cooling water between the cell assemblies. and forming a third cooling zone through which is flowable.

Further, in the method for manufacturing a nuclear fuel storage rack according to one aspect of the present invention, the rack body includes the cell assemblies arranged side by side, and the third cooling area between the cell assemblies. It is preferred to have a securing support member through which each said cell assembly is secured.

According to the present invention, in the storage cell, a plurality of storage areas are arranged side by side by combining a plurality of plate members, and the first cooling area and the second cooling area are provided between the storage areas. As a result, a cooling area can be secured between storage areas into which nuclear fuel is inserted. Further, in the nuclear fuel storage rack, the support member supports each cell assembly and secures the third cooling region between each cell assembly, thereby easily configuring the storage region for inserting the individual nuclear fuel. and each cooling area can be secured between storage areas. The cooling zones represented by the first cooling zone, the second cooling zone, the third cooling zone, etc. have the role of removing the decay heat of the spent nuclear fuel and moderating fast neutrons into thermal neutrons. If the fast neutrons are moderated to thermal neutrons, the neutron absorber will efficiently absorb the neutrons, so that the neutron absorbers can shield the neutrons.

1 is a perspective view of a storage pit; FIG. FIG. 2 is a perspective view of a nuclear fuel storage rack according to an embodiment of the invention. FIG. 3 is an exploded perspective view of a nuclear fuel storage rack according to an embodiment of the present invention. 4 is a perspective view of a small cell assembly and a cell assembly in a storage cell according to an embodiment of the invention; FIG. FIG. 5 is an exploded perspective view of a small cell assembly according to an embodiment of the invention. FIG. 6 is a part drawing of a small cell assembly according to an embodiment of the present invention. FIG. 7 is an enlarged cross-sectional view taken along line AA of FIG. FIG. 8 is a part drawing of a small cell assembly according to an embodiment of the present invention. FIG. 9 is a part drawing of a small cell assembly according to an embodiment of the present invention. 10 is an enlarged cross-sectional view taken along line CC of FIG. 9. FIG. 11 is a partially enlarged perspective view of a small cell assembly according to an embodiment of the present invention; FIG. FIG. 12 is an exploded perspective view of a small cell assembly according to an embodiment of the invention; FIG. 13 is a part drawing of a small cell assembly according to an embodiment of the present invention. 14 is an enlarged cross-sectional view taken along line DD of FIG. 13. FIG. 15 is a partially enlarged perspective view of a small cell assembly according to an embodiment of the present invention; FIG. FIG. 16 is an exploded perspective view of a small cell assembly according to an embodiment of the invention; FIG. 17 is a part drawing of a small cell assembly according to an embodiment of the present invention. 18 is an enlarged cross-sectional view along EE of FIG. 17. FIG. 19 is a partially enlarged perspective view of a small cell assembly according to an embodiment of the present invention; FIG. FIG. 20 is a partial enlarged view of a small cell assembly according to an embodiment of the invention. FIG. 21 is a partial enlarged view of a small cell assembly according to an embodiment of the invention. FIG. 22 is a partially enlarged view of a small cell assembly according to an embodiment of the invention; FIG. 23 is a partially enlarged perspective view of a cell assembly according to an embodiment of the invention; FIG. 24 is a partially enlarged cross-sectional view of a nuclear fuel storage rack according to an embodiment of the present invention. FIG. 25 is a partially enlarged cross-sectional view of a nuclear fuel storage rack according to an embodiment of the present invention.

EMBODIMENT OF THE INVENTION Below, embodiment which concerns on this invention is described in detail based on drawing. In addition, this invention is not limited by this embodiment. In addition, components in the following embodiments include components that can be easily replaced by those skilled in the art, or components that are substantially the same.

1 is a perspective view of a storage pit; FIG.

The storage pit 101 stores used fuel assemblies that have been used in nuclear reactors in nuclear power plants and unused fuel assemblies. A fuel assembly is an assembly in which nuclear fuel, which is a plurality of fuel rods, is bundled in a rectangular shape. The fuel assembly is therefore a so-called nuclear fuel. For example, when used in a pressurized water reactor, the fuel assembly is in the form of a rectangular square with a side of about 0.2 m and an elongated prism shape with a length exceeding 4 m. When it is used in a boiling water reactor, it has a rectangular shape with a side of about 0.15 m and a length of about 4.5 m.
The storage pit 101 is configured as a pool of rectangular concrete frame with an open top. The storage pit 101 has a rectangular floor surface 101a and vertical wall surfaces 101b of side walls surrounding the floor surface 101a in four directions. In this storage pit 101, the nuclear fuel storage rack 1 is arranged on the floor surface 101a. The nuclear fuel storage rack 1, which will be described later in detail, is constructed such that the top is open and the nuclear fuel is inserted from above. In the storage pit 101, the cooling water 103 is stored inside, and the nuclear fuel is stored and stored in the nuclear fuel storage rack 1 in a state where the nuclear fuel is erected.

Although not shown in the drawing, the storage pit 101 has a floor surface 101a and a concrete inner surface of the vertical wall surface 101b with a lining. The lining is made of austenitic stainless steel with a thickness of about 3 mm to 5 mm, and protects the inner surfaces of the floor surface 101a and the vertical wall surface 101b of the storage pit 101.

FIG. 2 is a perspective view of the nuclear fuel storage rack according to this embodiment. FIG. 3 is an exploded perspective view of the nuclear fuel storage rack according to this embodiment.

The nuclear fuel storage rack 1 has a rack body 11 and storage cells 12 arranged in the rack body 11 and into which nuclear fuel is inserted.

The rack body 11 is made of stainless steel and includes a base 11A, an outer frame 11B, a support grid (support member) 11C, a reinforcing member 11D, and legs 11E. These connections are made by welding or by bolts or screws.

The base 11A is formed in a rectangular shape in plan view and forms the base of the rack body 11. As shown in FIG.

The outer frame 11</b>B is formed as a rectangular plate material, is provided so as to rise upward from each side of the base 11</b>A, forms a rectangular cylinder in a plan view, and forms the outer peripheral portion of the rack body 11 . The outer frame 11B supports upper, central, and lower support grids 11C, which will be described later. Although not shown in the figure, the outer frame 11B is configured to surround each support grid 11C so as to support upper, central, and lower support grids 11C, which will be described later. Alternatively, although not shown in the drawings, it may be formed of diagonal members such as braces (X-shaped, V-shaped) made of band steel in place of the outer frame 11B.

The support grid 11C supports the storage cells 12. As shown in FIG. The support grid 11C is formed with a plurality of grids 11Ca that support a plurality of cell assemblies 13, which will be described later, in the storage cells 12. As shown in FIG. In this embodiment, the lattice 11Ca is formed in a rectangular shape, and 3×3 partitions 11Cb are arranged in line in order to insert the cell assemblies 13 in one support lattice 11C. The support grids 11C are provided at three locations, for example, an upper portion, a central portion, and a lower portion, within the cylinder formed by the outer frame 11B of the rack body 11. As shown in FIG. The support grids 11C at the top, center, and bottom are provided so that the grids 11Ca communicate with each other in the vertical direction in a plan view.

The reinforcing member 11D connects the upper and lower support grids 11C, and is provided so as to overlap the frame forming the grid 11Ca of the support grid 11C in plan view. A plurality of reinforcing members 11D are obliquely arranged in the vertical direction while overlapping the plurality of frames of the support grid 11C in plan view. A plurality of reinforcing members 11D are provided to intersect and are joined to each other by welding or the like at the intersecting portions.

A plurality of legs 11E are provided on the bottom surface of the base 11A. The leg portion 11E is provided slidably on the floor surface 101a. The rack body 11 is independently supported on the floor surface 101a by the legs 11E, and is movable relative to the floor surface 101a. Therefore, the nuclear fuel storage rack 1 described in this embodiment is a so-called free-standing rack. Note that the nuclear fuel storage rack 1 may be one in which the rack body 11 is fixed to the floor surface 101a or the vertical wall surface 101b.

The rack body 11 preferably has a rectangular parallelepiped outer shape, and a plurality (12 in FIG. 1) of the rack body 11 are arranged at a predetermined distance from the four vertical wall surfaces 101b that surround the storage pit 101 in a rectangular shape. They are arranged in a rectangular shape in four directions on the floor surface 101a.

As shown in FIG. 3, the storage cell 12 includes a plurality of cell assemblies 13 . Each cell assembly 13 is inserted along upper, middle, and lower lattices 11Ca communicating in the vertical direction in each support lattice 11C of the rack body 11, and is supported with its lower end placed on the upper surface of the base 11A. The cell assemblies 13 are respectively inserted into the partitions 11Cb partitioned by the nine grids 11Ca of the support grid 11C. The cell assembly 13 is formed in a rectangular cylindrical shape and provided with a plurality of storage areas 15 into which nuclear fuel is inserted. In this embodiment, nine storage areas 15 are provided in a 3×3 array in one cell assembly 13 .

Although FIG. 3 shows an example in which nine cell assemblies 13 are arranged in the rack body 11, the present invention is not limited to this. 16 grids 11Ca of x4 may be provided and 16 cell assemblies 13 may be arranged. Also, the number of storage areas 15 in one cell assembly 13 is not limited to nine. For example, although not shown in the drawing, twelve (4×3=12) may be arranged in line. A detailed configuration of the storage cell 12 will be described later.

Therefore, in the nuclear fuel storage rack 1, the nuclear fuel inserted into each storage area 15 of the plurality of cell assemblies 13 of the storage cells 12 is supported at its lower end by the upper surface of the base 11A and is surrounded by the storage cells 12 and the support grid 11C. are supported and stored in the cooling water 103 of the storage pit 101 in a form that is surrounded by the outer frame 11B to ensure seismic strength.

Further, in the nuclear fuel storage rack 1, the plurality of cell assemblies 13 of the storage cells 12 are inserted from above into the grids 11Ca of the support grids 11C, which are the support members, and the upper, middle, and lower peripheries of the grids 11Ca are inserted. supported by a frame. Therefore, since the frame of the grid 11Ca of the support grid 11C exists between the plurality of cell assemblies 13, the cooling area (third cooling area) in which the cooling water 103 of the storage pit 101 can flow area) is secured. As a result, the fast neutrons emitted from the nuclear fuel can be moderated to thermal neutrons and the decay heat of the nuclear fuel can be removed.

Further, in the nuclear fuel storage rack 1, the rack body 11 in which the cell assemblies 13 are arranged side by side has support grids 11C that support the plurality of cell assemblies 13 inside thereof. The frames of the central portion and the lower lattice 11Ca are connected by a reinforcing member 11D. The reinforcing member 11D reinforces the structural strength of the rack body 11 and enhances the earthquake resistance. As a result, the seismic strength can be improved and the nuclear fuel can be protected. Note that the reinforcing member 11D is not limited to being applied to the rack body 11 in which the above-described cell assemblies 13 are arranged side by side. For example, a plurality of storage cells are provided so as to each have a storage area into which the nuclear fuel is inserted, and the rack body 11 is arranged in the rack body 11 in the direction in which the nuclear fuel is inserted into the storage area so that the storage cells are arranged side by side. A plurality of support grids, which are support members, may be arranged, and a reinforcing member 11D may be provided to connect each support member between storage cells. Even in such a configuration, the reinforcing member 11D can reinforce the structural strength of the rack body 11, improve the earthquake resistance, improve the earthquake resistance, and protect the nuclear fuel.

Further, the nuclear fuel storage rack 1 is provided with a through hole 11Aa in the base 11A. The through-hole 11</b>Aa is provided substantially in the center of each storage area 15 of the plurality of cell assemblies 13 in the storage cell 12 . The through-hole 11Aa is inside each storage area 15 and sends the cooling water 103 of the storage pit 101 to the nuclear fuel inserted in each storage area 15 . As a result, the fast neutrons emitted from the nuclear fuel can be moderated to thermal neutrons and the decay heat of the nuclear fuel can be removed.

A detailed configuration of the storage cell 12 will be described below.

FIG. 4 is a perspective view of the small cell assembly 14 and the cell assembly 13 in the storage cell 12 according to this embodiment. FIG. 5 is an exploded perspective view of the small cell assembly 14 according to this embodiment. FIG. 6 is a component diagram of the small cell assembly 14 according to this embodiment. 7 is an enlarged cross-sectional view taken along line AA of FIG. 6 and an enlarged cross-sectional view taken along line BB of FIG. FIG. 8 is a component diagram of the small cell assembly 14 according to this embodiment. FIG. 9 is a component diagram of the small cell assembly 14 according to this embodiment. 10 is an enlarged cross-sectional view taken along line CC of FIG. 9. FIG. FIG. 11 is a partially enlarged perspective view of the small cell assembly 14 according to this embodiment. FIG. 12 is an exploded perspective view of the small cell assembly 14 according to this embodiment. FIG. 13 is a component diagram of the small cell assembly 14 according to this embodiment. 14 is an enlarged cross-sectional view taken along line DD of FIG. 13. FIG. FIG. 15 is a partially enlarged perspective view of the small cell assembly 14 according to this embodiment. FIG. 16 is an exploded perspective view of the small cell assembly 14 according to this embodiment. FIG. 17 is a component diagram of the small cell assembly 14 according to this embodiment. 18 is an enlarged cross-sectional view along EE of FIG. 17. FIG. FIG. 19 is a partially enlarged perspective view of the small cell assembly 14 according to this embodiment. 20 to 22 are partially enlarged views of the small cell assembly 14 according to this embodiment. FIG. 23 is a partially enlarged perspective view of the cell assembly 13 according to this embodiment. 4 to 23, the cell assembly 13 and the small cell assembly 14 are laid down, and the storage area 15 is shown extending in the horizontal direction.

As described above, the storage cell 12 includes a plurality of cell assemblies 13 (see FIG. 3). Each cell assembly 13 includes a plurality of small cell assemblies 14, as shown in FIG. That is, the storage cell 12 includes a plurality of small cell assemblies 14 and a plurality of cell assemblies 13 including the plurality of small cell assemblies 14 .

The small cell assembly 14 is made of a plate made of a neutron absorbing material. The neutron absorber is made of stainless steel to which at least one of boron and gadolinium is added, or an aluminum composite material containing at least one of a boron compound (preferably boron carbide) and gadolinium. Accordingly, the cell assembly 13 including a plurality of small cell assemblies 14 is similarly formed of plate material made of neutron absorbing material.

The cell assembly 13 of this embodiment is constructed by combining three small cell assemblies 14, as shown in FIG. The number of small cell assemblies 14 that form the cell assembly 13 is not limited to this.

In FIG. 4, the three small cell assemblies 14 are designated as small cell assembly 14A, small cell assembly 14B, and small cell assembly 14C, respectively. The small cell assembly 14A is provided on one side of the cell assembly 13 . The small cell assembly 14B is centrally provided in the cell assembly 13. As shown in FIG. Small cell assembly 14C is provided on the other side of cell assembly 13 . In this manner, the cell assembly 13 is configured by stacking and combining the small cell assembly 14A, the small cell assembly 14B, and the small cell assembly 14C.

As shown in FIG. 5, the small cell assembly 14A is composed of two side plates 16A and 16B and six partition plates 16C.

One side plate 16A, as shown in FIGS. 6 and 7, has a length longer than the length of the nuclear fuel by, for example, about 20 mm to 400 mm, and has a plurality of nuclear fuels (three in this embodiment) so as to accommodate a plurality of nuclear fuels. It has a width wider than the width of a minute. Here, the direction corresponding to the length dimension of the nuclear fuel is defined as the length direction, and the direction corresponding to the width dimension of the nuclear fuel is defined as the width direction.

It is recommended that the side plate 16A have a maximum dimension of 1 m or less in the width direction, considering the ease of manufacturing the material to which the neutron absorbing material is added. In the neutron absorber described above, edge cracks occur at the edges in the width direction during rolling during the manufacturing process. Therefore, it is necessary to use a special manufacturing method that does not cause such edge cracks, or to remove the edge cracks by cutting them. It is not easy to manufacture a plate that is wide in the width direction. For this reason, the side plate 16A preferably has a maximum width dimension of 1 m or less, which is relatively easy to manufacture. In the small cell assemblies 14A, 14B, and 14C, the number of nuclear fuel storage areas 15, that is, the number of nuclear fuel storage areas 15, is determined based on the maximum widthwise dimension of the side plate 16A.

The side plate 16A is provided with a convex portion 16Aa and a concave portion 16Ab at both ends in the width direction. The convex portions 16Aa and the concave portions 16Ab are provided alternately in the length direction. The side plate 16A of the present embodiment is provided with protrusions 16Aa on both ends in the length direction, and recesses 16Ab and protrusions 16Aa are alternately provided from there. The convex portion 16Aa and the concave portion 16Ab are formed to have the same size in the length direction, and only the convex portions 16Aa on both ends in the length direction are formed to have about half the size. Also, the convex portion 16Aa and the concave portion 16Ab are formed with dimensions that allow insertion of at least the thickness of the partition plate 16C.

Also, the side plate 16A is provided with a slit 16Ac. The slit 16Ac has the same thickness as the partition plate 16C, and is formed with a dimension that allows the partition plate 16C to be inserted. The slits 16Ac extend in the length direction of the side plate 16A, and are provided in plurality at predetermined intervals in the length direction. The arrangement of the slits 16Ac in the length direction is the same as the arrangement of the recesses 16Ab in the length direction. A plurality of (four in this embodiment) slits 16Ac are provided in the width direction of the side plate 16A. The slits 16Ac arranged on both sides in the width direction are arranged with an interval a covering the width of the nuclear fuel between them and the recesses 16Ab. The slits 16Ac adjacent in the width direction to the slits 16Ac on both sides in the width direction allow the cooling water 103 to flow so that the fast neutrons emitted from the nuclear fuel can be moderated into thermal neutrons and the decay heat of the nuclear fuel can be removed. They are arranged with an interval b. In addition, the slits 16Ac adjacent to each other in the width direction with respect to the slits 16Ac on both sides in the width direction are arranged with an interval a covering the width of the nuclear fuel. Therefore, the four slits 16Ac are arranged at three intervals a in the width direction, and are arranged at intervals b between two intervals a. The protrusion 16Ca of the partition plate 16C shown in FIG. 9 is fitted into the slit 16Ac of the side plate 16A across the gaps a and b. The interval a is the interval for forming the storage area 15 for the nuclear fuel, and the interval b is the interval for forming the first cooling area 17 .

The other side plate 16B, as shown in FIG. 8, has a length longer than the length of the nuclear fuel, and a width wider than the width of a plurality of nuclear fuels (three in this embodiment) so as to accommodate a plurality of nuclear fuels. have. The other side plate 16B is formed to have the same length and width as the one side plate 16A. Here, the direction corresponding to the length dimension of the nuclear fuel is defined as the length direction, and the direction corresponding to the width dimension of the nuclear fuel is defined as the width direction.

It is recommended that the side plate 16B have a maximum width of 1 m or less, considering the ease of manufacturing the material to which the neutron absorbing material is added. In the neutron absorber described above, edge cracks occur at the edges in the width direction during rolling during the manufacturing process. Therefore, it is necessary to use a special manufacturing method that does not cause such edge cracks, or to remove the edge cracks by cutting them. It is not easy to manufacture a plate that is wide in the width direction. Therefore, like the side plate 16A, the side plate 16B preferably has a maximum width dimension of 1 m or less. In the small cell assemblies 14A, 14B, and 14C, the number of nuclear fuel storage areas 15, that is, the number of nuclear fuel storage areas 15, is determined based on the maximum widthwise dimension of the side plate 16B.

The side plate 16B is provided with a convex portion 16Ba and a concave portion 16Bb at both ends in the width direction. The convex portions 16Ba and the concave portions 16Bb are alternately provided in the length direction. The side plate 16B of the present embodiment is provided with concave portions 16Bb on both ends in the length direction, from which convex portions 16Ba and concave portions 16Bb are provided alternately. The convex portion 16Ba and the concave portion 16Bb are formed to have the same size in the length direction, and only the concave portions 16Bb on both ends in the length direction are formed to have about half the size. Moreover, the convex portion 16Ba and the concave portion 16Bb are formed with dimensions that allow insertion of at least the thickness of the partition plate 16C.

Also, the side plate 16B is provided with a slit 16Bc. The slit 16Bc has a thickness equivalent to that of the partition plate 16C, and is formed with a dimension that allows insertion of the partition plate 16C. The slits 16Bc extend in the length direction of the side plate 16B, and are provided in plurality at predetermined intervals in the length direction. The arrangement of the slits 16Bc in the length direction is the same as the arrangement of the recesses 16Bb in the length direction. A plurality of (four in the present embodiment) slits 16Bc are provided in the width direction of the side plate 16B. The slits 16Bc, which are arranged on both sides in the width direction, are arranged with an interval a covering the width of the nuclear fuel between them and the recesses 16Bb. The slits 16Bc adjacent in the width direction to the slits 16Bc on both sides in the width direction are spaced so that the cooling water can flow so that the fast neutrons emitted from the nuclear fuel can be moderated into thermal neutrons and the decay heat of the nuclear fuel can be removed. It is arranged with b. Also, the slits 16Bc adjacent in the width direction to the slits 16Bc on both sides in the width direction are arranged with an interval a covering the width of the nuclear fuel. Therefore, the four slits 16Bc are arranged at three intervals a in the width direction, and are arranged at intervals b between two intervals a. The protrusions 16Ca of the partition plate 16C shown in FIG. 9 are fitted into the slits 16Bc of the side plate 16B across the gaps a and b. The interval a is the interval for forming the storage area 15 for the nuclear fuel, and the interval b is the interval for forming the first cooling area 17 .

As shown in FIGS. 9 and 10, the partition plate 16C has a length longer than the length of the nuclear fuel and a width wider than the width of one nuclear fuel so as to accommodate a plurality of nuclear fuels. The partition plate 16C is formed to have the same length as the side plates 16A and 16B. Here, the direction corresponding to the length dimension of the nuclear fuel is defined as the length direction, and the direction corresponding to the width dimension of the nuclear fuel is defined as the width direction.

The partition plate 16C is provided with a convex portion (protruding piece) 16Ca and a concave portion 16Cb on one side in the width direction. The convex portions 16Ca and the concave portions 16Cb are alternately provided in the length direction. The partition plate 16C of the present embodiment is provided with concave portions 16Cb on both ends in the length direction, from which convex portions 16Ca and concave portions 16Cb are provided alternately. The convex portion 16Ca and the concave portion 16Cb are formed to have the same size in the length direction, and only the concave portions 16Cb on both ends in the length direction are formed to have about half the size. Moreover, the protrusion 16Ca and the recess 16Cb are formed in the thickness of one of the side plates 16A. It is formed with a dimension c added with

Moreover, the partition plate 16C is provided with a convex portion 16Cc and a concave portion 16Cd on the other side in the width direction. The convex portions 16Cc and the concave portions 16Cd are alternately provided in the length direction. The partition plate 16C of the present embodiment is provided with protrusions 16Cc on both ends in the length direction, from which recesses 16Cd and protrusions 16Cc are provided alternately. The convex portion 16Cc and the concave portion 16Cd are formed to have the same size in the length direction, and only the convex portions 16Cc on both ends in the length direction are formed to have about half the size. Moreover, the convex portion 16Cc and the concave portion 16Cd are formed with a dimension d corresponding to the thickness of the other side plate 16B or more.

In addition, in this embodiment, the side plates 16A and 16B and the partition plate 16C are formed with the same thickness.

As shown in FIGS. 5 and 11, the small cell assembly 14A has two side plates 16A and 16B arranged parallel to each other with their plate surfaces facing each other, and six partition plates 16C between the side plates 16A and 16B. are provided perpendicularly to the side plates 16A and 16B. Specifically, in FIGS. 6 to 10, at both ends in the width direction of one side plate 16A, the convex portion 16Aa and the concave portion 16Cb of the partition plate 16C are fitted together, and the concave portion 16Ab and the convex portion 16Ca of the partition plate 16C are engaged with each other. fit together. Also, the projection 16Ca of the partition plate 16C is inserted into the slit 16Ac of one side plate 16A and fitted. At both ends in the width direction of the other side plate 16B, the projection 16Ba and the recess 16Cd of the partition plate 16C are fitted together, and the recess 16Bb and the projection 16Cc of the partition plate 16C are fitted together. Also, the projection 16Cc of the partition plate 16C is inserted into the slit 16Bc of the other side plate 16B and fitted. Then, the fitting portions are joined by welding.

As a result, the partition plate 16C secures the space a for inserting the nuclear fuel between the side plates 16A and 16B, and the space a for inserting the nuclear fuel between the partition plates 16C is secured, thereby forming the small cell assembly. In 14A, a plurality (three in this embodiment) of storage areas 15 surrounded by side plates 16A and 16B and partition plates 16C are arranged side by side in the width direction. In addition, by ensuring a space b between the partition plates 16C that allows the cooling water to flow, in the small cell assembly 14A, the cooling water is stored between the storage areas 15 surrounded by the side plates 16A and 16B and the partition plate 16C. A first cooling area 17 is formed through which the cooling water 103 in the pit 101 can flow. Also, in the small cell assembly 14A, the projections 16Ca of the partition plates 16C protrude outside one side plate 16A.

As shown in FIG. 12, the small cell assembly 14B is composed of two side plates 16A and 16B and six partition plates 16D.

The side plates 16A, 16B have the same configuration as the side plates 16A, 16B of the small cell assembly 14A, and the description thereof is omitted.

As shown in FIGS. 13 and 14, the partition plate 16D has a length longer than the length of the nuclear fuel and a width wider than the width of one nuclear fuel so as to accommodate a plurality of nuclear fuels. The partition plate 16D is formed to have the same length as the side plates 16A and 16B. Here, the direction corresponding to the length dimension of the nuclear fuel is defined as the length direction, and the direction corresponding to the width dimension of the nuclear fuel is defined as the width direction.

The partition plate 16D is provided with a convex portion (protruding piece) 16Da and a concave portion 16Db on one side in the width direction. The convex portions 16Da and the concave portions 16Db are alternately provided in the length direction. The partition plate 16D of the present embodiment is provided with concave portions 16Db at both ends in the length direction, from which convex portions 16Da and concave portions 16Db are provided alternately. The convex portion 16Da and the concave portion 16Db are formed to have the same size in the length direction, and only the concave portions 16Db on both ends in the length direction are formed to have about half the size. In addition, the protrusion 16Da and the recess 16Db are formed in the thickness of one of the side plates 16A so that the cooling water can flow in such a manner that the fast neutrons emitted from the nuclear fuel can be moderated into thermal neutrons and the decay heat of the nuclear fuel can be removed. It is formed with a dimension c added with

In addition, the partition plate 16D is provided with a convex portion (protruding piece) 16Dc and a concave portion 16Dd on the other side in the width direction. The convex portions 16Dc and the concave portions 16Dd are alternately provided in the length direction. The partition plate 16D of the present embodiment is provided with protrusions 16Dc on both ends in the length direction, from which the recesses 16Dd and the protrusions 16Dc are provided alternately. The convex portion 16Dc and the concave portion 16Dd are formed to have the same size in the length direction, and only the convex portions 16Dc on both ends in the length direction are formed to have about half the size. In addition, the protrusion 16Dc and the recess 16Dd are formed in the thickness of the other side plate 16B so that the cooling water can flow in such a manner that the fast neutrons emitted from the nuclear fuel can be moderated into thermal neutrons and the decay heat of the nuclear fuel can be removed. It is formed with a dimension c added with

In addition, in this embodiment, the side plates 16A and 16B and the partition plate 16D are formed with the same thickness.

As shown in FIGS. 12 and 15, the small cell assembly 14B has two side plates 16A and 16B arranged parallel to each other with their plate surfaces facing each other, and six partition plates 16D between the side plates 16A and 16B. are provided perpendicularly to the side plates 16A and 16B. Specifically, in FIGS. 6 to 8 and FIGS. 13 to 14, at both ends in the width direction of one side plate 16A, the convex portion 16Aa is fitted to the concave portion 16Db of the partition plate 16D, and the concave portion 16Ab and the partition plate are fitted. The convex portion 16Da of 16D is fitted. Also, the projection 16Da of the partition plate 16D is inserted into the slit 16Ac of one side plate 16A and fitted. At both ends in the width direction of the other side plate 16B, the projection 16Ba and the recess 16Dd of the partition plate 16D are fitted together, and the recess 16Bb and the projection 16Dc of the partition plate 16D are fitted together. Also, the projection 16Dc of the partition plate 16D is inserted into the slit 16Bc of the other side plate 16B and fitted. Then, the fitting portions are joined by welding.

As a result, the partition plate 16D secures the space a for inserting the nuclear fuel between the side plates 16A and 16B, and the space a for inserting the nuclear fuel between the partition plates 16D is secured. In 14B, a plurality (three in this embodiment) of storage areas 15 surrounded by side plates 16A and 16B and partition plates 16D are arranged side by side in the width direction. In addition, by ensuring a space b between the partition plates 16D through which the cooling water can flow, in the small cell assembly 14B, the cooling water is stored between the storage areas 15 surrounded by the side plates 16A and 16B and the partition plate 16D. A first cooling area 17 is formed through which the cooling water 103 in the pit 101 can flow. Also, in the small cell assembly 14B, the protrusion 16Da of each partition plate 16D protrudes outside one side plate 16A. Also, in the small cell assembly 14B, the projections 16Dc of each partition plate 16D protrude outside the other side plate 16B.

As shown in FIG. 16, the small cell assembly 14C is composed of two side plates 16A and 16B and six partition plates 16E.

The side plates 16A and 16B have the same configuration as the side plates 16A and 16B of the small cell assemblies 14A and 14B, and the description thereof is omitted.

As shown in FIGS. 17 and 18, the partition plate 16E has a length longer than the length of the nuclear fuel and a width wider than the width of one nuclear fuel so as to accommodate a plurality of nuclear fuels. The partition plate 16E is formed to have the same length as the side plates 16A and 16B. Here, the direction corresponding to the length dimension of the nuclear fuel is defined as the length direction, and the direction corresponding to the width dimension of the nuclear fuel is defined as the width direction.

The partition plate 16E is provided with a convex portion 16Ea and a concave portion 16Eb on one side in the width direction. The protrusions 16Ea and the recesses 16Eb are alternately provided in the length direction. The partition plate 16E of the present embodiment is provided with concave portions 16Eb on both ends in the length direction, and convex portions 16Ea and concave portions 16Eb are provided alternately from these. The convex portion 16Ea and the concave portion 16Eb are formed to have the same dimension in the length direction, and only the concave portions 16Eb on both end sides in the length direction are formed to about half the dimension. Moreover, the convex portion 16Ea and the concave portion 16Eb are formed with a dimension d corresponding to the thickness of one side plate 16A.

In addition, the partition plate 16E is provided with a convex portion (protruding piece) 16Ec and a concave portion 16Ed on the other side in the width direction. The convex portions 16Ec and the concave portions 16Ed are alternately provided in the length direction. The partition plate 16E of the present embodiment is provided with protrusions 16Ec on both ends in the length direction, from which the recesses 16Ed and the protrusions 16Ec are provided alternately. The convex portion 16Ec and the concave portion 16Ed are formed to have the same dimension in the length direction, and only the convex portions 16Ec on both ends in the length direction are formed to have approximately half the dimension. In addition, the protrusion 16Ec and the recess 16Ed are formed in the thickness of the other side plate 16B so that the cooling water can flow through the space b so that fast neutrons emitted from the nuclear fuel can be moderated into thermal neutrons and the decay heat of the nuclear fuel can be removed. It is formed with a dimension c added with

In addition, in this embodiment, the side plates 16A and 16B and the partition plate 16E are formed with the same thickness.

As shown in FIGS. 16 and 19, the small cell assembly 14C has two side plates 16A and 16B arranged parallel to each other with their plate surfaces facing each other, and six partition plates 16E between the side plates 16A and 16B. are provided perpendicularly to the side plates 16A and 16B. Specifically, in FIGS. 6 to 8 and FIGS. 17 to 18, at both ends in the width direction of one side plate 16A, the convex portion 16Aa and the concave portion 16Eb of the partition plate 16E are fitted, and the concave portion 16Ab and the partition plate are fitted. The projection 16Ea of 16E is fitted. Also, the projection 16Ea of the partition plate 16E is inserted into the slit 16Ac of one side plate 16A and fitted. At both ends in the width direction of the other side plate 16B, the protrusion 16Ba and the recess 16Ed of the partition plate 16E are fitted together, and the recess 16Bb and the protrusion 16Ec of the partition plate 16E are fitted together. Also, the protrusion 16Ec of the partition plate 16E is inserted into the slit 16Bc of the other side plate 16B and fitted. Then, the fitting portions are joined by welding.

As a result, the partition plate 16E secures the space a for inserting the nuclear fuel between the side plates 16A and 16B, and the space a for inserting the nuclear fuel between the partition plates 16E is secured, thereby forming a small cell assembly. At 14C, a plurality (three in this embodiment) of storage areas 15 surrounded by side plates 16A and 16B and a partition plate 16E are arranged side by side in the width direction. In addition, by ensuring a space b between the partition plates 16E that allows the cooling water to flow, in the small cell assembly 14C, the cooling water is stored between the storage areas 15 surrounded by the side plates 16A and 16B and the partition plate 16E. A first cooling area 17 is formed through which the cooling water 103 in the pit 101 can flow. Also, in the small cell assembly 14C, the projections 16Ec of each partition plate 16E protrude to the outside of the other side plate 16B.

Here, when joining the small cell assembly 14, as shown in FIG. 20, the partition plates 16C, 16D, and 16E form a groove 16F in the portion located inside the side plates 16A and 16B. There is a method of joining by groove welding 21. When joining the small cell assembly 14, as shown in FIG. 21, the width dimension of the side plates 16A and 16B is increased, and the dimensions of the projections 16Aa and 16Ba and the recesses 16Ab and 16Bb are adjusted to the partition plates 16C, 16D and 16E. There is also a method of forming internal corners between the side plates 16A, 16B and the partition plates 16C, 16D, 16E and joining them by fillet welding 22. Also, when joining the small cell assembly 14, as shown in FIG. 22, an opening (preferably a rectangular There is a method of providing an opening (not shown), inserting the wedge member 16G into the opening, and welding the retaining member 16H to the wedge member 16G to prevent it from coming off. By welding and fixing the retainer member 16H to the wedge member 16G, welding distortion of the side plates 16A and 16B and the partition plate 16D can be avoided, so that the small cell assembly 14 can be manufactured with high accuracy. In FIG. 22, the wedge member 16G is inserted into the protrusions 16Da, 16Dc, and 16Ec of the partition plate 16D projecting outside the side plates 16A and 16B, and the wedge member 16G is fixed to the side plates 16A and 16B and the partition plate 16D by welding. may Since this welding is a very small amount of welding to prevent the wedge member 16G from slipping out, the welding strain generated in the side plates 16A and 16B and the partition plate 16D is negligibly small. Welding distortion occurs only in the weakest wedge member 16G, and does not affect the side plates 16A, 16B and partition plate 16D.

In the small cell assembly 14A, welding of the convex portion 16Ca of the partition plate 16C that protrudes outward from the slit 16Ac of the side plate 16A and the side plate 16A and the convex portion of the partition plate 16C that protrudes outward from the slit 16Bc of the side plate 16B It is preferable not to weld 16Cc and side plate 16B. In the small cell assembly 14B, welding of the protrusion 16Da of the partition plate 16D projecting outward from the slit 16Ac of the side plate 16A and the side plate 16A, and protrusion of the partition plate 16D projecting outward from the slit 16Bc of the side plate 16B It is preferable not to weld 16Dc and side plate 16B. In the small cell assembly 14C, welding of the protrusion 16Ea of the partition plate 16E projecting outward from the slit 16Ac of the side plate 16A and the side plate 16A, and protrusion of the partition plate 16E projecting outward from the slit 16Bc of the side plate 16B It is preferable not to weld 16Ec and side plate 16B. By doing so, the welding strain on the side plates 16A and 16B and the partition plate 16D becomes negligibly small.

Then, the small cell assemblies 14 (14A, 14B, 14C) constructed in this manner are joined as shown in FIG. In FIG. 4, the plate surfaces of one side plate 16A of the small cell assembly 14A and the other side plate 16B of the small cell assembly 14B are opposed to each other, and the opposing small cell assemblies 14A and 14B are joined by welding. . Also, the plate surfaces of one side plate 16A of the small cell assembly 14B and the other side plate 16B of the small cell assembly 14C are made to face each other, and the opposing small cell assemblies 14B and 14C are joined by welding.

Specifically, when the small cell assembly 14A and the small cell assembly 14B are joined together, the projections 16Aa at both ends in the width direction of one side plate 16A of the small cell assembly 14A and the other projections 16Aa of the small cell assembly 14B The projecting portions 16Dc of the partition plate 16D positioned at both ends in the width direction of the side plate 16B are joined by welding. In addition, the projections 16Ca of the partition plate 16C located at both ends in the width direction of one side plate 16A in the small cell assembly 14A and the projections 16Ba at both ends in the width direction of the other side plate 16B in the small cell assembly 14B and are joined by welding. In addition, partition plates 16C positioned at both ends in the width direction of one side plate 16A in the small cell assembly 14A, partition plates 16D positioned at both ends in the width direction of the other side plate 16B in the small cell assembly 14B, are joined by welding. When connecting the small cell assembly 14B and the small cell assembly 14C, the protrusions 16Aa at both ends in the width direction of one side plate 16A of the small cell assembly 14B and the width of the other side plate 16B of the small cell assembly 14C The projections 16Ec of the partition plate 16E located at both ends in the direction are joined by welding. In addition, the protrusions 16Da of the partition plate 16D located at both ends in the width direction of one side plate 16A in the small cell assembly 14B and the protrusions 16Ba at both ends in the width direction of the other side plate 16B in the small cell assembly 14C and are joined by welding. In addition, partition plates 16D positioned at both ends in the width direction of one side plate 16A in the small cell assembly 14B, partition plates 16E positioned at both ends in the width direction of the other side plate 16B in the small cell assembly 14C, are joined by welding. Thus, the cell assembly 13 is constructed.

As shown in FIG. 23, the cell assembly 13 has nine storage areas 15 arranged in a 3×3 arrangement by joining the small cell assemblies 14A, 14B, and 14C. be done. Also, in joining the small cell assembly 14A and the small cell assembly 14B, the protrusion 16Ca of each partition plate 16C projecting outward from one side plate 16A of the small cell assembly 14A and the other side plate 16C of the small cell assembly 14B Between the outer surface of one side plate 16A of the small cell assembly 14A and the outer surface of the other side plate 16B of the small cell assembly 14B by the convex portion 16Dc of each partition plate 16D projecting to the outside of the side plate 16B A second cooling area 18 is formed having a gap b through which cooling water can flow. Also, in joining the small cell assembly 14B and the small cell assembly 14C, the protrusion 16Da of each partition plate 16D projecting outside one side plate 16A of the small cell assembly 14B and the other side plate 16D of the small cell assembly 14C Between the outer surface of one side plate 16A of the small cell assembly 14B and the outer surface of the other side plate 16B of the small cell assembly 14C by the convex portion 16Ec of each partition plate 16E projecting to the outside of the side plate 16B A second cooling area 18 having a gap b through which the cooling water 103 of the storage pit 101 can flow is formed to surround the storage area 15 .

The thickness of the side plates 16A, 16B and the partition plates 16C, 16E, 16D is set to a thickness necessary to keep the nuclear fuel stored in the storage area 15 below criticality. Since it is difficult to roll it into a thin plate, and if it is too thick, it may crack into two sheets.

24 and 15 are partially enlarged sectional views of the nuclear fuel storage rack according to this embodiment.

As shown in FIGS. 2 and 3, the plurality of cell assemblies 13 of the storage cells 12 configured as described above are arranged in upper, middle, and lower portions communicating in the vertical direction in each support grid 11C of the rack body 11. is inserted along the lattice 11Ca of the substrate 11A, and the lower end is placed and supported on the upper surface of the substrate 11A. As shown in FIGS. 24 and 25, the presence of the frame of the grid 11Ca of the support grid 11C between the plurality of cell assemblies 13 allows the cooling water 103 of the storage pit 101 to flow between the cell assemblies 13. A flowable third cooling area 19 is ensured. As a result, the fast neutrons emitted from the nuclear fuel can be moderated to thermal neutrons and the decay heat of the nuclear fuel can be removed.

2 and 3 show an embodiment in which the support grids 11C are installed at three locations, the upper portion, the center portion, and the lower portion, but the number of locations is not necessarily limited to three. Alternatively, an appropriate number larger than this may be installed.

Here, if there is a gap between the frame of the grid 11Ca of the support grid 11C and the cell assembly 13, as shown in FIGS. A locating member 20 consisting of a shim or wedge may be provided between them. As a result, the third cooling region 19 can be secured between the cell assemblies 13, and the cell assemblies 13 can be positioned and fixed to the frame of the grid 11Ca of the support grid 11C. In FIG. 24, the positioning member 20 is formed in a plate shape (or wedge shape) and is inserted between the frame of the grid 11Ca of the support grid 11C and the cell assembly 13, and the frame of the grid 11Ca of the support grid 11C. It is attached to the support grid 11C by fixing by welding the stoppers 20a that are caught on the upper and lower ends. 25, the positioning member 20 is formed in a plate shape (or wedge shape) and is inserted between the frame of the grid 11Ca of the support grid 11C and the cell assembly 13, and the bent portion 20b at the upper end is It is attached to the support grid 11C by hooking on the frame of the grid 11Ca of the support grid 11C and fixing the fastener 20a to the lower end by welding. Alternatively, in a state in which the positioning member 20 is inserted between the frame of the grid 11Ca of the support grid 11C and the cell assembly 13, the cell assembly 13, the positioning member 20, and the frame of the grid 11Ca are penetrated. The cell assembly 13 may be fixed to the frame of the lattice 11Ca with bolts 20c. Since the mass of the cell assembly 13 is assumed to be equivalent to several hundred kg, the cell assembly 13 is simply inserted into the section 11Cb of the rack body 11 into which the cell assembly 13 is inserted. may be

As described above, the storage cell 12 of this embodiment includes the cell assembly 13 composed of a plurality of small cell assemblies 14. The small cell assembly 14 includes a pair of opposing side plates 16A and 16B and a pair of opposing side plates 16A and 16B. a plurality of partition plates 16C (16D, 16E) arranged so as to connect the side plates 16A, 16B of the pair of opposing side plates 16A, 16B and the plurality of partition plates 16C (16D, 16E) A plurality of storage areas 15 configured to allow nuclear fuel to be inserted are arranged side by side, and a first cooling area 17 in which cooling water 103 can flow is formed between the storage areas 15, and the cell assemblies 13 are adjacent to each other. A plurality of small cell assemblies 14 are arranged so that the side plates 16A and 16B of the small cell assemblies 14 face each other. A cooling region 18 is formed.

According to this storage cell 12, a plurality of storage areas 15 are arranged side by side by combining a plurality of plate materials (side plates 16A and 16B, partition plates 16C (16D and 16E)), and between each storage area 15 A first cooling area 17 and a second cooling area 18 are provided. As a result, the cooling areas 17 and 18 can be secured between the storage areas 15 into which the nuclear fuel is inserted.

In addition, in the storage cell 12 of the present embodiment, the small cell assembly 14A (14B, 14C) has a convex portion as a projecting piece that a part of the partition plate 16C (16D, 16E) penetrates to the outside of the side plates 16A, 16B. 16Ca (16Da, 16Dc, 16Ec), and the second cooling region 18 is preferably defined by the projections 16Ca (16Da, 16Dc, 16Ec) in a state where the cell assembly 13 is joined.

Therefore, since the second cooling region 18 between the small cell assemblies 14A, 14B, 14C is defined by the projections 16Ca, 16Da, 16Dc, 16Ec of the partition plates 16C, 16D, 16E, the second cooling region 18 is can be easily defined.

In addition, in the storage cell 12 of this embodiment, the projections 16Ca, 16Da, 16Dc, and 16Ec are intermittently provided through the side plates 16A and 16B to form the plurality of small cell assemblies 14A, 14B, and 14C. In the joined state of the cell assembly 13, the protrusions 16Ca (16Da) of one small cell assembly 14A (14B) and the protrusions 16Dc (16Ec) of the other small cell assembly 14B (14C) alternate. is preferably placed in the

Therefore, by alternately arranging the protrusions 16Ca (16Da) of one small cell assembly 14A (14B) and the protrusions 16Dc (16Ec) of the other small cell assembly 14B (14C), one The bonding strength between the small cell assembly 14A (14B) and the other small cell assembly 14B (14C) can be improved, and the second cooling region 18 can be easily defined.

Further, the nuclear fuel storage rack 1 of this embodiment includes the storage cells 12 described above, the rack body 11 that supports a plurality of cell assemblies 13 in the storage cells 12 and is placed on the floor surface 101a of the storage pit 101, The rack body 11 includes a support grid 11C as a support member that supports the cell assemblies 13 side by side and forms a third cooling region 19 between the cell assemblies 13 in which cooling water can flow. have

According to this nuclear fuel storage rack 1, the support grid 11C supports each cell assembly 13, and by securing the third cooling region 19 between each cell assembly 13, a storage space for inserting individual nuclear fuel is provided. The area 15 can be easily constructed, and the cooling areas 17 , 18 , 19 for disposing the cooling water 103 can be secured between the storage areas 15 .

In the nuclear fuel storage rack 1 of this embodiment, the rack body 11 has a plurality of support grids 11C arranged in the direction in which the nuclear fuel is inserted into the storage area 15, and the support grids 11C are connected between the cell assemblies 13. It is preferable to have a reinforcing member 11D.

Therefore, the strength of the rack body 11 can be improved by providing the reinforcing member 11D between the support grids 11C.

Further, the nuclear fuel storage rack 1 of this embodiment has a positioning member 20 which is arranged between the support grid 11C and the cell assembly 13 to fix the position of the cell assembly 13 with respect to the support grid 11C. is preferred.

Therefore, by defining the position of the cell assembly 13 with respect to the support grid 11C with the positioning member 20, the third cooling region 19 can be defined.

The manufacturing method of the storage cell 12 of this embodiment comprises a pair of side plates 16A and 16B facing each other, and a plurality of partition plates 16C (16D and 16E) arranged to connect the pair of side plates 16A and 16B facing each other. Thus, a plurality of small cell assemblies 14 are formed in which a plurality of storage areas 15 in which nuclear fuel can be inserted are arranged side by side, and a first cooling area 17 in which cooling water 103 can flow is formed between the storage areas 15. a step of arranging a plurality of small cell assemblies 14 such that the side plates 16A and 16B of the adjacent small cell assemblies 14 face each other, and performing a second step in which the cooling water 103 can flow between the adjacent small cell assemblies 14; and configuring the cell assembly 13 to form the cooling region 18 .

According to the manufacturing method of the storage cell 12, a plurality of storage areas 15 are arranged side by side by combining a plurality of plate materials (side plates 16A, 16B, partition plates 16C (16D, 16E)), and each storage area 15 A first cooling area 17 and a second cooling area 18 are provided between. As a result, the cooling areas 17 and 18 can be secured between the storage areas 15 into which the nuclear fuel is inserted.

In addition, in the manufacturing method of the storage cell 12 of the present embodiment, the small cell assembly 14A (14B, 14C) has the partition plate 16C (16D, 16E) as a protruding piece that partially penetrates the side plates 16A, 16B to the outside. are joined as a cell assembly 13 via the protrusions 16Ca (16Da, 16Dc, 16Ec) to define a second cooling region 18 .

Therefore, since the second cooling region 18 between the small cell assemblies 14A, 14B, 14C is defined by the projections 16Ca, 16Da, 16Dc, 16Ec of the partition plates 16C, 16D, 16E, the second cooling region 18 is can be easily defined.

In addition, in the manufacturing method of the storage cell 12 of the present embodiment, the wedge member 16G is inserted into the protrusions 16Ca (16Da, 16Dc, 16Ec) penetrating the outside of the side plates 16A and 16B, and the retaining member that retains the wedge member 16G. Preferably, 16H is welded to wedge member 16G.

Therefore, when assembling the small cell assemblies 14A, 14B, and 14C, the wedge member 16G is used for assembly, and the retaining member 16H is welded to the wedge member 16G to fix the wedge member 16G. As a result, the number of welded portions of the side plates 16A, 16B and the partition plates 16C (16D, 16E) can be reduced and welding strain can be avoided, so that the small cell assemblies 14A, 14B, 14C can be manufactured with high accuracy.

The manufacturing method of the nuclear fuel storage rack 1 of the present embodiment includes a pair of opposing side plates 16A and 16B and a plurality of partition plates 16C (16D and 16E) arranged to connect the pair of opposing side plates 16A and 16B. ), a small cell assembly 14 in which a plurality of storage areas 15 configured to allow insertion of nuclear fuel are arranged side by side, and a first cooling area 17 in which cooling water 103 can flow is formed between the storage areas 15. a step of arranging a plurality of small cell assemblies 14 so that the side plates 16A and 16B of the adjacent small cell assemblies 14 face each other so that the cooling water 103 can flow between the adjacent small cell assemblies 14; A step of forming a plurality of cell assemblies 13 forming the second cooling area 18, and a step of arranging the plurality of cell assemblies 13 side by side on the rack body 11 placed on the floor surface 101a of the storage pit 101. and forming a third cooling region 19 between each cell assembly 13 through which the cooling water 103 can flow.

According to this method of manufacturing the nuclear fuel storage rack 1, the storage areas 15 into which the individual nuclear fuels are inserted can be easily configured, and the cooling areas 17, 18, 18, 18, 18, 18, 18, 17, 18, 17, 18, 18, 18 and 18 in which the cooling water 103 is arranged between the storage areas 15. 19 can be secured.

In addition, in the method of manufacturing the nuclear fuel storage rack 1 of this embodiment, the rack body 11 supports the cell assemblies 13 in parallel and secures the third cooling area 19 between the cell assemblies 13. It is preferable to have a support grid 11C as a support member and fix each cell assembly 13 via the support grid 11C.

Therefore, the support grid 11C supports each cell assembly 13 and secures the third cooling region 19 between each cell assembly 13, thereby facilitating the configuration of the storage region 15 into which the individual nuclear fuel is inserted. and the cooling areas 17 , 18 , 19 in which the cooling water 103 is arranged can be secured between the storage areas 15 .

By the way, the free-standing nuclear fuel storage rack 1 has high earthquake resistance by absorbing the horizontal force acting upon occurrence of an earthquake by the fluid additional damping effect of the cooling water 103 and the sliding resistance of the nuclear fuel storage rack 1 . On the other hand, when the earthquake level increases, a rocking event occurs in which one side in the moving direction is locked and the other side in the moving direction is lifted up, causing the nuclear fuel storage racks 1 to collide with each other or the nuclear fuel storage racks 1 to be stored. Collision with the floor surface 101a and the vertical wall surface 101b of the pit 101, and the nuclear fuel storage rack 1 approaching the vertical wall surface 101b are problems. If the nuclear fuel storage racks 1 collide with each other, the load may be transmitted to the rack body 11 and the storage cells 12, resulting in excessive stress. If the nuclear fuel storage rack 1 collides with the floor surface 101a and the vertical wall surface 101b of the storage pit 101, the floor surface 101a and the vertical wall surface 101b may not be protected if the lining of the floor surface 101a and the vertical wall surface 101b is damaged. be. When the nuclear fuel storage rack 1 approaches the vertical wall surface 101b of the storage pit 101, the nuclear fuel may approach the passage or the like existing on the other side of the wall of the storage pit 101 and be affected by radiation.

Now, let us consider the correlation between the overturning moment and the stabilizing moment. Mass M of nuclear fuel storage rack 1, gravitational acceleration G, horizontal seismic acceleration FH, vertical seismic acceleration FV, height H from center of gravity of nuclear fuel storage rack 1 to floor surface 101a, center of gravity of nuclear fuel storage rack 1 Let L be the horizontal distance from the position to the rotation axis (the leg 11E closest to the overturning direction) when the nuclear fuel storage rack 1 is locked.

Horizontal seismic force of nuclear fuel storage rack 1 F=M×FH
Vertical seismic force of nuclear fuel storage rack 1 P=M×(G±FV)
Seismic force P=M×(G-FV) in the lifting direction to the nuclear fuel storage rack 1
Overturning moment of nuclear fuel storage rack 1 Mt=F×H
Stable moment of nuclear fuel storage rack 1 Ma=P×L
Minimum stable moment of nuclear fuel storage rack 1 Mamin=M×(G−FV)×L

If the stable moment Ma is larger than the overturning moment Mt (Mt<Ma), the nuclear fuel storage rack 1 will not overturn, and if the stable moment Ma is smaller than the overturning moment Mt (Mt>Ma), the nuclear fuel storage rack 1 will Fall down. Therefore, the height of the nuclear fuel (height H from the center of gravity of the nuclear fuel storage rack 1 to the floor 101a) is determined in order to place the free-standing nuclear fuel storage rack 1 stably on the floor 101a. Therefore, it is desirable to increase the horizontal distance L from the rotation axis to the center of gravity.

However, as described above, the neutron absorber has edge cracks at the edges in the width direction during rolling during the manufacturing process. It is not easy to manufacture a plate that is wide in the width direction, for example, it needs to be removed by hand. For this reason, it is desirable that the neutron absorber has a maximum dimension in the width direction of 1 m or less, which makes it possible to manufacture the neutron absorber.

In this embodiment, the storage cell 12 includes two side plates 16A and 16B facing each other, and partition plates 16C (16D and 16E) provided between the side plates 16A and 16B. A small cell assembly having a first cooling area 17 in which a plurality of storage areas 15 into which nuclear fuel is inserted are arranged side by side by a plurality of partition plates 16C (16D, 16E) and cooling water 103 can flow between the storage areas 15. 14 and the side plates 16A, 16B of the plurality of small cell assemblies 14A, 14B, 14C are opposed to each other so as to form a second cooling area 18 in which cooling water can flow. and a cell assembly 13 to which 14C is joined.

Therefore, according to the storage cell 12 of the present embodiment, even if the maximum dimension of the side plates 16A, 16B in the width direction of the small cell assembly 14 is reduced, the plurality of small cell assemblies 14A, 14B, 14C can be joined together. Since the cell assembly 13 is configured in such a manner, the horizontal distance L of the cell assembly 13 can be increased, and the stable moment Ma can be made larger than the overturning moment Mt. Further, according to the nuclear fuel storage rack 1 of the present embodiment, since the plurality of storage cells 12 are arranged in the rack body 11, the horizontal distance L of the rack body 11 can be increased, and the stable moment Ma can be made larger than the overturning moment Mt. can.

Reference Signs List 1 nuclear fuel storage rack 11 rack body 11A base 11Aa through hole 11B outer frame 11C support grid (support member)
11Ca Lattice 11Cb Section (cell assembly insertion section)
11D Reinforcement member 11E Leg 12 Storage cell 13 Cell assembly 14 (14A, 14B, 14C) Small cell assembly 15 Storage area 16A Side plate 16Aa Convex portion 16Ab Concave portion 16Ac Slit 16B Side plate 16Ba Convex portion 16Bb Concave portion 16Bc Slit 16C Partition plate 16Ca Convex portion 16Cb Concave portion 16Cc Convex portion 16Cd Concave portion 16D Partition plate 16Da Convex portion 16Db Concave portion 16Dc Convex portion 16Dd Concave portion 16E Partition plate 16Ea Convex portion 16Eb Concave portion 16Ec Convex portion 16Ed Concave portion 16F Groove 16G Wedge member 16H First cooling region 18H Second cooling area 19 Third cooling area 20 Positioning member 20a Fastener 20b Bent portion 20c Bolt 21 Groove weld 22 Fillet weld 101 Storage pit 101a Floor surface 101b Vertical wall surface 103 Cooling water

Claims (8)

including a cell assembly consisting of a plurality of sub-cell assemblies;
The small cell assembly includes:
a pair of side plates facing each other; and a plurality of partition plates arranged to connect the pair of side plates facing each other;
A plurality of storage areas configured so that nuclear fuel can be inserted are arranged side by side by a pair of said side plates facing each other and a plurality of said partition plates, and a first cooling area in which cooling water can flow is formed between said storage areas. is,
The cell assembly is
A second cooling system in which a plurality of small cell assemblies are arranged such that the side plates of adjacent small cell assemblies face each other, and cooling water can flow between the adjacent small cell assemblies. a region is formed,
In the small cell assembly, a part of the partition plate has a protruding piece penetrating to the outside of the side plate, and the second cooling region is defined by the protruding piece in a state of being joined as the cell assembly. cage,
The protruding pieces are intermittently provided to penetrate the outside of the side plate, and in a state in which a plurality of the small cell assemblies are joined as the cell assembly, the protruding piece of one of the small cell assemblies , alternately arranged with the projecting pieces of the other small cell assembly,
storage cell. A storage cell according to claim 1;
a rack body that supports a plurality of the cell assemblies in the storage cells and is mounted on the floor surface of the storage pit;
including
A nuclear fuel storage rack, wherein the rack body has support members that support the cell assemblies side by side and form a third cooling region between the cell assemblies in which cooling water can flow. 3. The nuclear fuel according to claim 2, wherein said rack body has a plurality of said support members arranged in a direction in which said nuclear fuel is inserted into said storage area, and has reinforcing members connecting each of said support members between said cell assemblies. storage rack. 4. A nuclear fuel storage rack according to claim 2, further comprising a positioning member disposed between said support member and said cell assembly for fixing the position of said cell assembly with respect to said support member. A plurality of storage areas in which nuclear fuel can be inserted are arranged side by side by a pair of opposing side plates and a plurality of partition plates arranged to connect the pair of opposing side plates, and each of the storage areas forming a plurality of small cell assemblies forming a first cooling region between which cooling water can flow;
A cell set in which a plurality of small cell assemblies are arranged so that the side plates of the adjacent small cell assemblies face each other, thereby forming a second cooling region between the adjacent small cell assemblies in which cooling water can flow. a step of forming a solid;
including
The small cell assembly has a protruding piece that a part of the partition plate penetrates to the outside of the side plate, and is joined as the cell assembly through the protruding piece to define the second cooling region,
The protruding pieces are intermittently provided to penetrate the outside of the side plate, and in a state in which a plurality of the small cell assemblies are joined as the cell assembly, the protruding piece of one of the small cell assemblies , alternately arranged with the projecting pieces of the other small cell assembly,
A method of manufacturing a storage cell. 6. The method of manufacturing a storage cell according to claim 5 , wherein a wedge member is inserted into said protruding piece penetrating to the outside of said side plate, and a retention member for retaining said wedge member is welded to said wedge member. A plurality of storage areas in which nuclear fuel can be inserted are arranged side by side by a pair of opposing side plates and a plurality of partition plates arranged to connect the pair of opposing side plates, and each of the storage areas forming a plurality of small cell assemblies forming a first cooling region between which cooling water can flow;
A cell set in which a plurality of small cell assemblies are arranged so that the side plates of the adjacent small cell assemblies face each other, thereby forming a second cooling region between the adjacent small cell assemblies in which cooling water can flow. A step of forming a plurality of solids;
A plurality of the cell assemblies are arranged side by side on a rack body placed on the floor of the storage pit, and a third cooling area is formed between the cell assemblies in which cooling water can flow. and
including
The small cell assembly has a protruding piece that a part of the partition plate penetrates to the outside of the side plate, and is joined as the cell assembly through the protruding piece to define the second cooling region,
The protruding pieces are intermittently provided to penetrate the outside of the side plate, and in a state in which a plurality of the small cell assemblies are joined as the cell assembly, the protruding piece of one of the small cell assemblies , alternately arranged with the projecting pieces of the other small cell assembly,
A method of manufacturing a nuclear fuel storage rack. The rack body has a support member for arranging the cell assemblies side by side and securing the third cooling region between the cell assemblies, 8. The method of manufacturing a nuclear fuel storage rack according to claim 7 , wherein the solid is fixed.

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