Radioactive material storage container and method for assembling a radioactive material storage container

Abstract

In a radioactive material storage container and a method for assembling a radioactive material storage container, damage to the drain pipe is prevented by preventing circumferential movement of the basket. [Solution] The device comprises a main body which is cylindrical in shape with a bottom and has a cylindrical cavity inside with an opening on one side in the axial direction; a basket which is placed in the cavity and divides into multiple storage compartments; a lid which is detachably attached to the opening; and an anti-rotation member which is fixed to the lower part of the inner wall inside the main body and abuts against the outer circumference of the basket to prevent the basket from moving in the circumferential direction.

Description

Technical Field

[0001] The present disclosure relates to a radioactive substance storage container and a method for assembling the radioactive substance storage container.

Background Art

[0002] At nuclear facilities, radioactive waste such as spent fuel generated in a nuclear reactor or the like is stored in a radioactive substance storage container (cask), transported to a storage facility, a reprocessing facility, or the like, and stored or reprocessed. The radioactive substance storage container is composed of a cask body having a bottomed cylindrical shape with an open top, and a lid portion fixed to the top of the cask body to close the opening. Further, a basket capable of storing a plurality of radioactive wastes is disposed inside the cask body of the radioactive substance storage container.

[0003] The operation of storing radioactive waste in a radioactive substance storage container is performed, for example, in a fuel pool. That is, the cask body is submerged in the water of the fuel pool, the radioactive waste in the water of the fuel pool is stored in the cask body, and a lid is attached to the opening. Then, the radioactive substance storage container storing the radioactive waste is lifted from the fuel pool to the work floor, and the lid is fixed to the cask body with bolts to close it. After that, the inside of the radioactive substance storage container is vacuum dried after the internal water is discharged. Examples of such radioactive substance storage containers include those described in Patent Document 1 below.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] The radioactive material storage container is equipped with a drain pipe for draining water from inside to the outside. The drain pipe is located inside the cask body, and when the primary lid is fixed to the opening of the cask body, the drain hole of the primary lid is connected to the upper end of the drain pipe. Inside the cask body is a basket capable of storing radioactive waste. The basket can move circumferentially inside the cask body. Therefore, if the basket inside the cask body moves circumferentially, there is a risk that it may come into contact with the drain pipe, damaging the drain pipe, the basket, and the radioactive waste.

[0006] This disclosure aims to solve the aforementioned problems and to provide a radioactive material storage container and a method for assembling a radioactive material storage container that prevent damage to the drain pipe by preventing circumferential movement of the basket. [Means for solving the problem]

[0007] To achieve the above objective, the radioactive material storage container of this disclosure comprises a main body having a bottomed cylindrical shape with a cylindrical cavity inside and an opening on one side in the axial direction; a basket disposed in the cavity and partitioning a plurality of storage compartments; a lid that is detachably attached to the opening; and an anti-rotation member fixed to the lower part of the inner wall inside the main body and in contact with the outer circumference of the basket to prevent the basket from moving in the circumferential direction.

[0008] Furthermore, the assembly method for the radioactive material storage container of this disclosure includes the steps of: fixing a lower guide to the bottom of a cylindrical main body with a bottom; inserting a basket having multiple storage compartments into the cavity of the main body; fixing an upper support to the inner wall of the upper part of the main body; arranging a drain pipe in the upper support and the lower guide; and fixing a lid with a sealing member attached to its back surface to the opening of the main body. [Effects of the Invention]

[0009] According to the radioactive material storage container and the method for assembling the radioactive material storage container of this disclosure, damage to the drain pipe can be prevented by preventing circumferential movement of the basket. [Brief explanation of the drawing]

[0010] [Figure 1] Figure 1 is a partially cutaway schematic diagram showing the internal structure of a radioactive material storage container. [Figure 2] Figure 2 is a horizontal cross-sectional view showing a radioactive material storage container. [Figure 3] Figure 3 is an assembled perspective view of a basket for storing radioactive materials. [Figure 4] Figure 4 is a perspective view showing a part of the drainage system. [Figure 5] Figure 5 is a longitudinal cross-sectional view showing the top of the radioactive material storage container. [Figure 6] Figure 6 is a perspective view showing the upper support structure of the drain pipe. [Figure 7] Figure 7 is a plan view showing the lower guide structure of the drain pipe. [Figure 8] Figure 8 is a longitudinal cross-sectional view showing the lower part of the radioactive material storage container. [Modes for carrying out the invention]

[0011] Preferred embodiments of the present disclosure will be described in detail below with reference to the drawings. However, these embodiments do not limit the present disclosure, and where there are multiple embodiments, they may be combinations of these embodiments. Furthermore, the components in the embodiments include those readily conceivable by those skilled in the art, those that are substantially identical, and those that are equivalent.

[0012] <Radioactive material storage container> Figure 1 is a partially cutaway schematic diagram showing the internal structure of a radioactive material storage container, Figure 2 is a horizontal cross-sectional view of the radioactive material storage container, and Figure 3 is an assembled perspective view of a basket for storing radioactive materials.

[0013] As shown in Figures 1 and 2, the cask 11, as a radioactive material storage container, comprises a cask body 12 and a lid 13. The cask body 12 has a body shell 21. The body shell 21 is cylindrical (in this embodiment, cylindrical in shape), with an opening 22 at its upper end and a closed lower end. The body shell 21 has a cavity 23 inside, and a basket 24 is placed in the cavity 23. The basket 24 is provided with a plurality of cells (storage compartments) 25 capable of individually storing radioactive materials (e.g., spent fuel assemblies). The body shell 21 is a forged product of carbon steel having a gamma-ray shielding function. However, stainless steel may be used instead of carbon steel for the body shell 21. Alternatively, the body shell 21 may be a casting of spheroidal graphite cast iron or carbon steel cast steel.

[0014] The cask body 12 has an outer cylinder 26 positioned on the outer circumferential surface of the main body shell 21 with a gap between them. Multiple copper heat transfer fins 27 are provided circumferentially spaced between the outer circumferential surface of the main body shell 21 and the inner circumferential surface of the outer cylinder 26 to conduct heat. In the space enclosed by the main body shell 21, the outer cylinder 26, and the heat transfer fins 27, a resin 28 is placed as a neutron shield. The resin 28 is a polymer material containing a large amount of hydrogen and contains boron or a boron compound having a neutron shielding function.

[0015] The cask body 12 is provided with a bottom portion 29 that protrudes below the closed lower end of the main body shell 21. The bottom portion 29 is formed to be smaller than the outer diameter of the cask body 12. The bottom portion 29 has a space enclosed by the closed lower end of the main body shell 21, and resin (neutron shielding material) is placed in this space.

[0016] The cask body 12 has trunnions 30 for lifting the cask 11 provided on the main body shell 21 at 90-degree or 180-degree intervals on the upper and lower parts of the cask 11. The trunnions 30 are provided by penetrating the outer cylinder 26 from the main body shell 21.

[0017] The lid part 13 is arranged at the opening 22 of the main body barrel 21. The lid part 13 closes the opening 22 to seal the main body barrel 21 (cask main body 12). The lid part 13 has a primary lid 31, a secondary lid 32, and a tertiary lid 33. The primary lid 31 is formed in a disk shape using carbon steel or stainless steel that shields gamma rays as the material. The secondary lid 32 covers the primary lid 31 and appears on the outside of the cask 11. Similar to the primary lid 31, it is formed in a disk shape using carbon steel or stainless steel that shields gamma rays as the material. A resin (neutron shield) 28 may be provided between the primary lid 31 and the secondary lid 32. The tertiary lid 33 is provided outside the secondary lid 32, but the tertiary lid 33 may be omitted. The tertiary lid 33 is formed in a disk shape using carbon steel or stainless steel that shields gamma rays as the material, similar to the primary lid 31 and the secondary lid 32.

[0018] The primary lid 31 is fixed to the first-stage part 22a formed at the opening 22 of the main body barrel 21 by bolts (not shown) made of carbon steel or stainless steel. The secondary lid 32 is fixed to the second-stage part 22b formed at the opening 22 of the main body barrel 21 by bolts (not shown) made of carbon steel or stainless steel. Although not shown, a metal gasket is provided between the primary lid 31 and the first-stage part 22a, and between the secondary lid 32 and the second-stage part 22b. The metal gasket ensures the sealing performance between the primary lid 31 and the first-stage part 22a, and between the secondary lid 32 and the second-stage part 22b. The tertiary lid 33 is fixed to the third-stage part 22c formed at the opening 22 of the main body barrel 21 by bolts (not shown) made of carbon steel or stainless steel.

[0019] In the nuclear power generation facility, for example, a plurality of spent fuel assemblies are stored in each cell 25 of the basket 24 of the main body barrel 21 of the cask 11 and sealed by the lid part 13. The cask 11 is, for example, transported from the nuclear power generation facility to the storage facility. During transportation, a transportation buffer (not shown) is attached to the cask 11. The transportation buffer is attached to the upper and lower parts of the cask main body 12. The cask 11 is loaded on the loading platform of the transportation vehicle in a lying-down state and transported to the storage facility.

[0020] <Basket> As shown in Figure 2, the main body shell 21 is provided with a cavity 23 that forms a cylindrical space inside. Note that the cavity 23 is not limited to a perfect cylinder shape, and may have notches or other features around its perimeter. The basket 24 is placed in the cavity 23. The basket 24 is provided with, for example, multiple cells 25 capable of accommodating multiple spent fuel assemblies.

[0021] As shown in Figure 3, the basket 24 is constructed by combining a plurality of plate-like members 41 and 42 in a grid pattern. Specifically, the basket 24 is constructed by combining a plurality of first plate-like members 41, which are spaced apart in the thickness direction, and a plurality of second plate-like members 42, which are also spaced apart in the thickness direction, in orthogonal directions. As a result, the basket 24 is divided into a plurality of cells 25 that are parallel to the lateral direction and extend vertically at predetermined intervals. The plurality of cells 25 are arranged along the radial direction of the cavity 23 and in mutually orthogonal X-axis and Y-axis directions.

[0022] Multiple plate-shaped members 41 and 42 are constructed by overlapping a rigid plate material 51, which serves as a strength member, and a functional plate material 52, which serves as a functional member, in the thickness direction. The functional member has one or more functions, either neutron absorption or thermal conductivity greater than or equal to that of the rigid plate material 51. Each plate material 51 and 52 has notches 53 and 54 formed at its upper and lower ends, and they are assembled so that the notches 53 and 54 fit together. The rigid plate material 51 is made of carbon steel, stainless steel, or aluminum alloy. The functional plate material 52 has a structure in which a ceramic layer containing boron carbide as a neutron absorber is wrapped in a stainless steel plate or aluminum alloy plate. Alternatively, the functional plate material 52 may be made of aluminum or an aluminum alloy with boron or a boron compound added as a neutron absorber. In addition to boron, gadolinium can be used for the functional plate material 52. Furthermore, in addition to aluminum or an aluminum alloy, stainless steel can be used for the functional plate material 52. The plate-like members 41 and 42 may be made from a single plate or from three or more plates.

[0023] <Drainage equipment> Figure 4 is a perspective view showing a part of the drainage system.

[0024] As shown in Figure 1, the cask 11 comprises a cask body 12 and a lid 13. The cask body 12 (body 21) has a basket 24 placed in a cavity 23. The cask 11 is equipped with a device for draining the water inside to the outside.

[0025] As shown in Figures 4 and 5, the drainage equipment 60, which is a device for draining water from inside the cask 11, has an air supply hole (not shown) provided in the primary cover 31 (cover portion 13), a drain hole 61 provided in the primary cover 31 (cover portion 13), and a drain pipe 62 provided in the main body 21. The drainage equipment 60 is positioned between the inner wall side portion 21a of the main body 21 and the outer periphery of the basket 24. Here, the outer periphery of the basket 24 is the longitudinal end portion (flat portion 41a, 42a) of the plate-shaped members 41, 42. The drain pipe 62 is adjacent to the inner wall side portion 21a of the main body 21 and is positioned along the axial direction of the main body 21. An upper support 63 is fixed to the upper inner wall side portion 21a of the main body 21. A lower guide 64 is fixed to the lower part 21b of the inner wall inside the main body 21. Specifically, the lower guide 64 is fixed to the upper surface 29a of the bottom 29. The drain pipe 62 is supported at its upper end by the upper support 63 and guided at its lower end by the lower guide 64.

[0026] <Upper structure of the radioactive material storage container> Figure 5 is a vertical cross-sectional view showing the upper part of the radioactive material storage container, and Figure 6 is a perspective view showing the upper support structure of the drain pipe.

[0027] As shown in Figures 5 and 6, the drain hole 61 is provided penetrating the primary cover 31 in the thickness direction. The drain hole 61 has a large diameter portion 71 and a small diameter portion 72. The large diameter portion 71 and the small diameter portion 72 are in communication with each other, with the large diameter portion 71 opening on the upper surface of the primary cover 31 and the small diameter portion 72 opening on the lower surface of the primary cover 31. A resin 28 is positioned above the primary cover 31. The resin 28 has a disc shape with approximately the same diameter as the primary cover 31. The resin 28 has a notch 73 positioned opposite the upper part of the large diameter portion 71 of the drain hole 61 provided in the primary cover 31, exposing the upper part of the large diameter portion 71. A drain pipe (not shown) can be connected to the large diameter portion 71 of the primary cover 31 from the outside.

[0028] The cask 11 is divided into spaces S by the flat portion 41a at the longitudinal end of the first plate-shaped member 41, the flat portion 42a at the longitudinal end of the second plate-shaped member 42, and the inner wall side portion 21a of the main body 21. Multiple spaces S are provided around the outer circumference of the basket 24 at intervals in the circumferential direction. The drain pipe 62 and the upper support 63 are located above one of the multiple spaces S.

[0029] The upper support 63 is fixed to the inner wall side portion 21a of the main body 21. The upper support 63 has a T-shape in plan view and has a mounting portion 63a and a support portion 63b. The mounting portion 63a of the upper support 63 is fixed to the inner wall side portion 21a of the main body 21 by a plurality of bolts 81. In this case, the main body 21 is provided with a notch 21c in the inner wall side portion 21a, and the mounting portion 63a is fixed to the bolts 81 while fitted into the notch 21c. The support portion 63b extends from the mounting portion 63a in a direction away from the inner wall side portion 21a of the main body 21 (inward in the radial direction of the main body 21). The support portion 63b has a notch 63c formed on the upper surface of the tip side, and a through hole 63d is formed at the tip of the notch 63c that penetrates along the axial direction of the main body 21.

[0030] The drain pipe 62 has a pipe body 62a and a support plate 62b. The pipe body 62a extends in the longitudinal direction (axial direction of the main body 21). The support plate 62b is disc-shaped and has a through hole for connecting to the pipe body 62a. The support plate 62b is integrally provided at the upper end of the pipe body 62a. The drain pipe 62 is inserted from above through the through hole 63d of the upper support 63, and the support plate 62b is supported by the support portion 63b of the upper support 63. At this time, the support plate 62b of the drain pipe 62 is placed on the notch 63c of the upper support 63, and the upper surface is continuous with the upper surface of the upper support 63 without a step, although there may be a step. In addition, a ring-shaped sealing member 82 is placed between the support plate 62b of the drain pipe 62 and the back surface of the primary cover 31. The sealing member 82 is fitted into the notch 31a formed on the back surface of the primary cover 31.

[0031] <Lower structure of the radioactive material storage container> Figure 7 is a plan view showing the lower guide structure of the drain pipe, and Figure 8 is a longitudinal cross-sectional view showing the lower part of the radioactive material storage container.

[0032] As shown in Figures 7 and 8, the lower guide 64 is fixed to the upper surface 29a of the bottom 29 of the main body 21. The lower guide 64 has an isotropic shape in plan view and has a support hole 64a that penetrates the main body 21 in the axial direction. However, the lower guide 64 is not limited to an isotropic shape, and may have any shape as long as it has two surfaces parallel to the planar portion 41a of the first plate-like member 41 and the planar portion 42a of the second plate-like member 42. The lower guide 64 is in close contact with the upper surface 29a of the bottom 29 of the main body 21 and is fixed to the upper surface 29a of the bottom 29 of the main body 21 by a plurality of bolts 91.

[0033] Furthermore, the bottom portion 29 of the main body 21 is provided with a recess 92 at a position opposite to the support hole 64a of the lower guide 64 on the upper portion 29a. The recess 92 is cylindrical in shape, and its bottom portion 92a is located lower than the upper portion 29a of the bottom portion 29. That is, when the cask 11 is upright, the bottom portion 92a of the recess 92 is located below the upper portion 29a of the bottom portion 29.

[0034] The drain pipe 62 is inserted through the support hole 64a of the lower guide 64 and positioned in the recess 92 of the bottom 29. In this case, the lower end of the drain pipe 62 is positioned with a gap between its outer circumferential surface and the inner circumferential surface of the support hole 64a. Furthermore, the lower end of the drain pipe 62 is positioned with a gap between its outer circumferential surface and the inner circumferential surface of the recess 92, and its lower surface is positioned with a gap between its bottom surface 92a of the recess 92. The lower guide 64 is also provided with a communication hole 64b at its lower end that connects the recess 92 to the outside.

[0035] The lower guide 64 functions as an anti-rotation member for the basket 24, with its outer circumference acting as an anti-rotation member. In other words, the lower guide 64, which supports the lower end of the drain pipe 62, functions as an anti-rotation member. As the lower guide 64, acting as an anti-rotation member, is fixed to the bottom 29 inside the main body 21, it abuts against the outer circumference of the basket 24, thereby preventing the basket 24 from moving in the circumferential direction. Therefore, the basket 24 does not come into contact with the drain pipe 62.

[0036] The lower guide 64, acting as an anti-rotation member, is positioned inside the main body 21, excluding the cells 25 of the basket 24. The lower guide 64, acting as an anti-rotation member, is positioned between the inner wall side portion 21a of the main body 21 and the outer periphery of the basket 24.

[0037] As described above, the basket 24 is formed by combining a plurality of first plate-shaped members 41 and a plurality of second plate-shaped members 42 in a grid pattern, thereby dividing a plurality of cells 25. Not only the drain pipe 62 and the upper support 63, but also the lower guide 64 is placed in the space S. The lower guide 64, acting as an anti-rotation member, prevents the basket 24 from moving in the circumferential direction by the contact between the planar portion 41a at the longitudinal end of the first plate-shaped member 41 and the planar portion 42a at the longitudinal end of the second plate-shaped member 42.

[0038] Furthermore, as shown in Figure 5, the basket 24 is positioned in the cavity 23 of the cask body 12 (body 21), but an axial gap H1 is provided between the upper end and the lower surface of the primary lid 31. Therefore, if the cask 11 is tipped over during transport, the basket 24 may move axially within the cavity 23 of the body 21 by the gap H1. On the other hand, as shown in Figure 8, the lower guide 64 is fixed to the bottom 29 of the body 21, ensuring an axial length H2 of the body 21.

[0039] Here, gap H1 < length H2. That is, the lower guide 64, which acts as an anti-rotation member, has an axial length of the main body 21 that is longer than the axial movement length of the basket 24. Therefore, even if the basket 24 moves to an upward position in the axial direction, the outer circumference of the basket 24, that is, the ends of the plate-like members 41 and 42, will come into contact with the lower guide 64, and thus it can function as an anti-rotation member.

[0040] <Method for assembling a radioactive material storage container> When assembling the cask 11, first, as shown in Figures 7 and 8, the lower guide 64 is fixed to the upper surface 29a of the bottom 29 of the main body 21 with a plurality of bolts 91. Next, as shown in Figure 1, the basket 24, assembled with a plurality of plate-like members 41 and 42, is inserted into the cavity 23 of the main body 21. At this time, the circumferential position of the basket 24 is adjusted so that the lower guide 64 is positioned in one of the spaces S on the outer circumference of the basket 24. When the lower guide 64 is positioned in one of the spaces S on the outer circumference of the basket 24, the lower guide 64 prevents the basket 24 from moving in the circumferential direction.

[0041] Next, as shown in Figures 5 and 6, the upper support 63 is fixed to the upper inner wall side portion 21a of the main body 21 with a plurality of bolts 81. The circumferential fixing position of the upper support 63 is the same as the circumferential fixing position of the lower guide 64. That is, screw holes for bolts 81 and 91 are formed at predetermined positions on the inner wall side portion 21a and the bottom portion 29 of the main body 21 so that the through hole 63d of the upper support 63 and the support hole 64d of the lower guide 64 are located in the same horizontal position. Then, the lower end of the drain pipe 62 is inserted through the through hole 63d of the upper support 63, and then descends and is inserted into the support hole 64a of the lower guide 64. Here, the drain pipe 62 is positioned longitudinally by the support plate 62b being supported by the support portion 63b of the upper support 63.

[0042] In this process, the drain pipe 62 is supported at its lower end by the lower guide 64 and at its upper end by the upper support 63. Then, a sealing member 82 is attached around the drain hole 61 on the underside of the primary cover 31. After that, the primary cover 31 is attached to the opening 22 of the main body 21 and secured with multiple bolts. At this time, the upper end of the drain pipe 62 is in communication with the drain hole 61.

[0043] When radioactive waste is to be stored inside the cask 11, the cask body 12 is submerged in the fuel pool water with the lower guide 64, basket 24, upper support 63, and drain pipe 62 assembled to the main body shell 21 of the cask body 12. Then, the radioactive waste in the fuel pool water is stored in each cell 25 of the cask body 12. Once the radioactive waste is stored inside the cask body 12, the primary cover 31 is attached to the opening 22 and closed. After that, the cask body 12 is lifted from the fuel pool to the work floor and the primary cover 31 is secured with bolts.

[0044] Then, air is supplied to the cavity 23 of the cask 11 through an air supply hole (not shown) provided in the primary lid 31, and the water in the cavity 23 is discharged through the drain hole 61 and the drain pipe 62. At this time, the water inside the cask body 12 (body shell 21) flows to the lower guide 64 side through the drain grooves of the plate-shaped members 41 and 42 that constitute the bottom of the basket 24, accumulates in the recess 92, and is discharged from the drain pipe 62. Once all the water inside the cask 11 has been discharged, the inside is vacuum-dried.

[0045] [Effects of this embodiment] The radioactive material storage container according to the first embodiment comprises a main body 21 having a bottomed cylindrical shape with a cylindrical cavity 23 inside and an opening 22 on one side in the axial direction; a basket 24 arranged in the cavity 23 and partitioning a plurality of cells (storage sections) 25; a lid 13 that is detachably attached to the opening 22; and a lower guide 64 as an anti-rotation member that is fixed to the bottom 29 inside the main body 21 and contacts the outer circumference of the basket 24 to prevent the basket 24 from moving in the circumferential direction.

[0046] According to the first embodiment of the radioactive material storage container, the lower guide 64, which acts as an anti-rotation member, is fixed to the bottom 29 of the main body 21. As a result, even if the basket 24 attempts to move circumferentially inside the main body 21, the outer circumference of the basket 24 comes into contact with the lower guide 64, preventing the basket 24 from moving circumferentially. Therefore, by preventing the circumferential movement of the basket 24, damage to the drain pipe 62 can be prevented.

[0047] The radioactive material storage container according to the second embodiment is the same as the radioactive material storage container according to the first embodiment, wherein the lower guide 64 is fixed to the bottom 29 inside the main body 21. This effectively prevents the circumferential movement of the basket 24.

[0048] The third embodiment of the radioactive material storage container is a radioactive material storage container according to the first or second embodiment, further comprising a lower guide 64 as an anti-rotation member, which is positioned inside the main body 21 excluding the cell 25. This prevents a reduction in the amount of radioactive waste that can be stored in the cell 25 by the lower guide 64.

[0049] The fourth embodiment of the radioactive material storage container is a radioactive material storage container according to any one of the first to third embodiments, and further, the lower guide 64 as an anti-rotation member is positioned between the inner wall side portion 21a of the main body 21 and the outer periphery of the basket 24. This eliminates the need to change the shape of the basket cells 25 and suppresses structural complexity.

[0050] The fifth embodiment of the radioactive material storage container is a radioactive material storage container according to any one of the first to fourth embodiments, further comprising a basket 24 in which a plurality of first plate-shaped members 41 and a plurality of second plate-shaped members 42 are arranged in a grid pattern to form a plurality of cells 25, and a lower guide 64 acting as an anti-rotation member prevents the circumferential movement of the basket 24 by abutting with at least one of the longitudinal ends of the first plate-shaped members 41 and the longitudinal ends of the second plate-shaped members 42. This makes it possible to form a contact portion for the lower guide 64 using the plurality of plate-shaped members 41 and 42 constituting the basket 24, thereby simplifying the structure of the basket 24.

[0051] The radioactive material storage container according to the sixth embodiment is a radioactive material storage container according to the fifth embodiment, wherein the lower guide 64 as an anti-rotation member is arranged in a space S partitioned by the planar portion 41a on the longitudinal end side of the first plate-shaped member 41, the planar portion 42a on the longitudinal end side of the second plate-shaped member 42, and the inner wall side portion 21a of the main body casing 21. This makes it possible to arrange the lower guide 64 without reducing the number of cells 25.

[0052] The radioactive material storage container according to the seventh embodiment is a radioactive material storage container according to any one of the first to sixth embodiments, and furthermore, the lower guide 64 as an anti-rotation member has an axial length of the basket 24 that is longer than the axial movement length of the basket 24. As a result, even if the basket 24 moves in the axial direction, the outer circumference of the basket 24 always comes into contact with the lower guide 64, and the lower guide 64 can appropriately prevent the circumferential movement of the basket 24.

[0053] The eighth embodiment of the radioactive material storage container is a radioactive material storage container according to any one of the first to seventh embodiments, further comprising a drain pipe 62 arranged axially inside the main body 21, with the lower end of the drain pipe 62 positioned on a lower guide 64 which serves as an anti-rotation member. This simplifies the structure by allowing the lower guide 64 to also function as an anti-rotation member.

[0054] The radioactive material storage container according to the ninth embodiment is a radioactive material storage container according to the eighth embodiment, further comprising: an upper support 63 fixed to the upper inner wall side portion 21a of the main body 21; a lower guide 64 fixed to the bottom portion 29; a drain pipe 62 whose upper end is supported by the upper support 63 and whose lower end is supported by the lower guide 64; and an anti-rotation member provided on the lower guide 64. This allows the lower guide 64 to appropriately prevent the circumferential movement of the basket 24.

[0055] The radioactive material storage container according to the tenth embodiment is a radioactive material storage container according to the ninth embodiment, further comprising an upper support 63 and a lower guide 64 fastened to the main body 21 by bolts 81 and 91. This facilitates the manufacture and dismantling of the main body 21.

[0056] The radioactive material storage container according to the 11th embodiment is a radioactive material storage container according to the 10th embodiment, further comprising an upper support 63 whose base end is engaged with a notch 21c provided in the inner wall of the main body 21 and fixed by a bolt 81. This allows the upper support 63 to be fixed to the main body 21 with high precision and firmness.

[0057] The radioactive material storage container according to the 12th embodiment is a radioactive material storage container according to any one of the 9th to 11th embodiments, further comprising a support hole 64a that penetrates the main body 21 in the axial direction of the lower guide 64, and the lower end of the drain pipe 62 is positioned in the support hole 64a. This allows the lower end of the drain pipe 62 to be properly supported by the support hole 64a of the lower guide 64.

[0058] The radioactive material storage container according to the 13th embodiment is a radioactive material storage container according to the 12th embodiment, further comprising a recess 92 on the upper surface 29a of the bottom 29 of the main body 21, facing the support hole 64a, and the lower end of the drain pipe 62 is positioned in the recess 92, passing through the support hole 64a. As a result, the lower end of the drain pipe 62 is positioned in the recess 92, which is lower than the bottom 29, allowing for proper drainage by the drain pipe 62. Furthermore, even if the drain pipe 62 expands due to heat, interference with the bottom 29 can be prevented.

[0059] The radioactive material storage container according to the 14th embodiment is a radioactive material storage container according to any one of the 9th to 13th embodiments, further comprising an upper support 63 provided with a through hole 63d along the axial direction of the main body 21, and a drain pipe 62 being supported by the upper support 63 by being inserted through the through hole 63d. This allows the upper end of the drain pipe 62 to be easily supported by the main body 21.

[0060] The radioactive material storage container according to the 15th embodiment is a radioactive material storage container according to any one of the first to 14th embodiments, further comprising a drain pipe 62 with a support plate 62b integrally provided at the upper end of the pipe body 62a, and a sealing member 82 provided between the upper part of the support plate 62b and the lower surface of the primary lid 31. This allows the drain hole 61 provided in the primary lid 31 and the drain pipe 62 supported by the main body 21 to communicate without any gaps.

[0061] The radioactive material storage container according to the 16th embodiment is a radioactive material storage container according to the 15th embodiment, further comprising a sealing member 82 provided on the lower surface of the primary lid 31. This prevents the sealing member 82 from falling off when the drain pipe 62 is installed.

[0062] The radioactive material storage container according to the 17th embodiment is a radioactive material storage container according to the 16th embodiment, further comprising a sealing member 82 mounted in a notch 31a provided on the lower surface of the primary lid 31. This allows the sealing member 82 to be mounted in the appropriate position on the lower surface of the primary lid 31.

[0063] The 18th embodiment of the method for assembling a radioactive material storage container includes the steps of: fixing a lower guide 64 to the bottom 29 of a cylindrical main body 21 with a bottom; inserting a basket 24, which is divided into a plurality of cells (storage sections) 25, into the cavity 23 of the main body 21; fixing an upper support 63 to the upper inner wall side portion 21a of the main body 21; arranging a drain pipe 62 on the upper support 63 and the lower guide 64; and fixing a primary lid 31 (lid portion 13) to the opening 22 of the main body 21.

[0064] According to the assembly method for a radioactive material storage container of the 18th embodiment, the lower guide 64, which acts as an anti-rotation member, is fixed to the bottom 29 of the main body 21. As a result, even if the basket 24 attempts to move circumferentially inside the main body 21, the outer circumference of the basket 24 comes into contact with the lower guide 64, preventing the basket 24 from moving circumferentially. Therefore, by preventing the circumferential movement of the basket 24, damage to the drain pipe 62 can be prevented.

[0065] In the above-described embodiment, a lower guide 64 supporting the lower end of the drain pipe 62 was used as an anti-rotation member, but the configuration is not limited to this. For example, an anti-rotation member may be provided separately from the lower guide 64 and fixed to the bottom 29 of the main body 21. [Explanation of Symbols]

[0066] 11. Cask (container for radioactive materials) 12 Cask body 13 Lid 21 Main body 22 Opening 23 Cavity 24 Basketball 25 cells (storage compartment) 26 Outer cylinder 27 Heat transfer fins 28 Resin 29 Bottom 30 Trunnion 31 Primary lid 32 Secondary lid 33 Tertiary lid 41 First plate-shaped member 42 Second plate-shaped member 51 Rigid plate material 52 Functional board materials 53, 54 Notches 60 Drainage equipment 61 Drain hole 62 Drain pipe 63 Upper support 64 Lower Guide 71 Large diameter section 72 Small diameter section 73 Notch 81 volts 82 sealing member 91 volts 92 recess S space part

Claims

1. The main body is cylindrical in shape with a bottom, and has a cylindrical cavity inside, with an opening on one side in the axial direction. A basket arranged in the cavity, which divides the cavity into multiple storage compartments, A lid portion that is detachably attached to the aforementioned opening, A rotation-preventing member is fixed to the lower part of the inner wall inside the main body and contacts the outer circumference of the basket to prevent the basket from moving in the circumferential direction. A radioactive material storage container equipped with [a specific feature].

2. The anti-rotation member is fixed to the bottom inside the main body. A radioactive material storage container according to claim 1.

3. The anti-rotation member is positioned inside the main body casing, excluding the storage section. A radioactive material storage container according to claim 1.

4. The anti-rotation member is positioned between the inner wall of the main body and the outer periphery of the basket. A radioactive material storage container according to claim 3.

5. The basket is formed by arranging a plurality of first plate-shaped members and a plurality of second plate-shaped members in a grid pattern to divide it into multiple cells, and the anti-rotation member prevents the basket from moving in the circumferential direction by contacting at least one of the longitudinal ends of the first plate-shaped members and the longitudinal ends of the second plate-shaped members. A radioactive material storage container according to claim 4.

6. The anti-rotation member is positioned in the space partitioned by the planar portion at the longitudinal end of the first plate-shaped member, the planar portion at the longitudinal end of the second plate-shaped member, and the inner wall portion of the main body. A radioactive material storage container according to claim 5.

7. The anti-rotation member is such that the axial length of the basket is longer than the axial length of movement in the basket. A radioactive material storage container according to claim 1.

8. A drain pipe is arranged axially inside the main body, and the lower end of the drain pipe is positioned on the anti-rotation member. A radioactive material storage container according to claim 1.

9. The main body has an upper support fixed to the upper inner wall and a lower guide fixed to the bottom, the drain pipe has its upper end supported by the upper support and its lower end supported by the lower guide, and the anti-rotation member is provided on the lower guide. A radioactive material storage container according to claim 8.

10. The upper support and the lower guide are fastened to the main body by bolts. A radioactive material storage container according to claim 9.

11. The upper support is secured by bolts, with its base end engaging with a notch provided in the inner wall of the main body. A radioactive material storage container according to claim 10.

12. The lower guide is provided with a support hole that penetrates the main body in the axial direction, and the drain pipe has its lower end positioned in the support hole. A radioactive material storage container according to claim 11.

13. A recess opposite to the support hole is provided on the upper surface of the bottom of the main body, and the drain pipe is positioned in the recess with its lower end passing through the support hole. A radioactive material storage container according to claim 12.

14. The upper support is provided with a through hole along the axial direction of the main body, and the drain pipe is supported by the upper support by being inserted through the through hole. A radioactive material storage container according to claim 10.

15. The drain pipe has a support plate integrally provided at the upper end of the pipe body, and a sealing member is provided between the upper part of the support plate and the lower surface of the lid. A radioactive material storage container according to claim 13.

16. The sealing member is provided on the lower surface of the lid, A radioactive material storage container according to claim 15.

17. The sealing member is fitted into a notch provided on the lower surface of the lid. A radioactive material storage container according to claim 16.

18. A step for fixing the lower guide to the bottom of the cylindrical body with a bottom, The steps include inserting a basket, which is divided into multiple storage compartments, into the cavity of the main body, The steps include fixing the upper support to the inner wall of the upper part of the main body, The steps include positioning the drain pipe on the upper support and the lower guide, The steps include fixing a lid portion with a sealing member attached to its back surface to the opening of the main body, A method for assembling a radioactive material storage container having [a specific feature / feature].

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