Storage unit

Abstract

The present invention provides a storage unit that protects casks during storage and removes heat. [Solution] The storage unit is placed inside a storage facility for a radioactive material storage container that stores radioactive material inside, and is equipped with protective equipment that covers at least the top of the radioactive material storage container with a predetermined gap between it and the container.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a storage unit.

BACKGROUND ART

[0002] In nuclear facilities, radioactive waste such as spent fuel generated in nuclear reactors and the like is stored in radioactive material storage containers (casks), transported to storage facilities, reprocessing facilities and the like, and stored or reprocessed. The radioactive material storage container is composed of a cylindrical body portion with a bottom and an open top, and a lid portion fixed to the top of the body portion to close the opening.

[0003] After transportation, the radioactive material storage container is stored in a storage location for several decades. The radioactive material storage container during storage is provided with cushioning materials at its axial ends, and deforms when colliding with a floor, wall or the like due to dropping, overturning, or moving, thereby absorbing the impact applied in the radial direction (for example, Patent Document 1).

PRIOR ART DOCUMENTS

PATENT DOCUMENTS

[0004]

PATENT DOCUMENT 1

SUMMARY OF THE INVENTION

PROBLEMS TO BE SOLVED BY THE INVENTION

[0005] When an earthquake occurs, there is a possibility that structures such as the ceiling of a building may collapse and fall, or debris may flow in and block the air flow path for heat removal. Even in such cases, it is necessary to secure the air flow path for heat removal while suppressing the impact load of the collapsed structure on the cask.

[0006] The present disclosure is made to solve the above-mentioned problems, and aims to provide a storage unit that protects the cask during storage and removes heat therefrom.

MEANS FOR SOLVING THE PROBLEMS

[0007] To achieve the above-mentioned objectives, a storage unit according to one aspect of the present disclosure is characterized by comprising: a protective device disposed inside a storage facility for a radioactive material storage container that stores radioactive material inside, and provided to cover at least the upper part of the radioactive material storage container with a predetermined gap between it and the container. [Effects of the Invention]

[0008] According to this disclosure, the effect of protecting the casks during storage and removing heat can be obtained. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 is a perspective view showing a section of a radioactive material containment container that has been fractured. [Figure 2] Figure 2 is a cross-sectional view showing the main part of a radioactive material containment container fitted with a buffer. [Figure 3] Figure 3 is a schematic perspective view showing the storage state of the radioactive material storage container held in the storage unit of the first embodiment. [Figure 4] Figure 4 is a front view showing the storage unit of the first embodiment. [Figure 5] Figure 5 is a side view showing the storage unit of the first embodiment. [Figure 6] Figure 6 is a side view showing the storage unit of the second embodiment. [Figure 7] Figure 7 is a side view showing the storage unit of the third embodiment. [Figure 8] Figure 8 is a front view showing the storage unit of the fourth embodiment. [Figure 9] Figure 9 is a side view showing the storage unit of the fourth embodiment. [Modes for carrying out the invention]

[0010] Embodiments relating to this disclosure will be described in detail below with reference to the drawings. However, the invention is not limited by these embodiments. Furthermore, the components in the embodiments described below include those that are easily substituted, substantially identical, or equivalent to those that can be substituted by those skilled in the art. In addition, various omissions, substitutions, or modifications of components in the embodiments described below are permitted without departing from the spirit of this disclosure. In the embodiments described below, necessary components will be described to illustrate the embodiments, while other components will be omitted, and identical components will be denoted by the same reference numerals, while different components will be denoted by different reference numerals.

[0011] [First Embodiment] [Storage container for radioactive materials] First, an example of the configuration of a radioactive material storage container according to this embodiment will be described using Figure 1. Figure 1 is a perspective view of a portion of the radioactive material storage container with a section cut away.

[0012] As shown in Figure 1, the cask 11, which serves as a container for radioactive material, comprises a cask body 12 and a lid 13.

[0013] The cask body 12 has a body shell 21. The body shell 21 is cylindrical (in this embodiment, cylindrical shape). The body shell 21 has an opening 22 formed at one end in the axial direction of the cylindrical shape (upper end in Figure 1), and the other end (lower end in Figure 1) is closed. The body shell 21 has a cavity 23 inside. A basket 24 is provided in the cavity 23. The basket 24 is provided with a plurality of cells 25 capable of independently storing radioactive material (e.g., spent fuel assemblies). The body shell 21 is a forged product of carbon steel having a gamma-ray shielding function, but stainless steel may be used instead of carbon steel, or it may be a casting of spheroidal graphite cast iron or carbon steel casting.

[0014] The cask main body 12 further includes an outer cylinder 26, heat transfer fins 27, and a resin (neutron shield) 28. The outer cylinder 26 is arranged on the outer peripheral surface of the main body barrel 21 with a predetermined gap therebetween. A plurality of the heat transfer fins 27 are provided in the circumferential direction between the outer peripheral surface of the main body barrel 21 and the inner peripheral surface of the outer cylinder 26. The heat transfer fins 27 are made of copper, and conduct heat between the outer peripheral surface of the main body barrel 21 and the inner peripheral surface of the outer cylinder 26. The resin 28 is provided in a space surrounded by the main body barrel 21, the outer cylinder 26, and the heat transfer fins 27. 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 main body 12 further has a bottom portion 29. The bottom portion 29 is provided so as to protrude axially outward (in FIG. 1, below the lower end) from the closed other end of the main body barrel 21. The bottom portion 29 has a space surrounded by the closed other end of the main body barrel 21, and a resin (neutron shield) is provided in the space.

[0016] The cask main body 12 is provided with trunnions 30 for lifting the cask 11 on the main body barrel 21. The trunnions 30 are provided to extend from the main body barrel 21 through the outer cylinder 26, and protrude to the outermost periphery of the cask 11.

[0017] The lid part 13 is provided at the opening 22 of the main body cylinder 21, closes the opening 22, and hermetically seals the main body cylinder 21 (the cask main body 12). The lid part 13 is configured to include 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 a material. The secondary lid 32 covers the axially outer side of the primary lid 31, and similarly to the primary lid 31, is formed in a disk shape using carbon steel or stainless steel that shields gamma rays as a material. A resin (neutron shield) 28 may be provided between the primary lid 31 and the secondary lid 32. The tertiary lid 33 covers the secondary lid 32 and the end edge 22c of the main body cylinder 21 and appears on the outer side of the cask 11, and similarly to the primary lid 31 and the secondary lid 32, is formed in a disk shape using carbon steel or stainless steel that shields gamma rays as a material. During storage, the lid part 13 may be provided with an adapter having no sealing function for attaching a storage buffer instead of the tertiary lid 33.

[0018] The primary lid 31 is fixed to the first step portion 22a formed in the opening 22 of the main body cylinder 21 by bolts (not shown) made of carbon steel or stainless steel, and is attached to the main body cylinder 21. The secondary lid 32 is fixed to the second step portion 22b formed in the opening 22 of the main body cylinder 21 by bolts (not shown) made of carbon steel or stainless steel, and is attached to the main body cylinder 21. Although not depicted, metal gaskets are provided between the primary lid 31 and the first step portion 22a and between the secondary lid 32 and the second step portion 22b. The metal gaskets ensure the sealing performance between the primary lid 31 and the first step portion 22a and between the secondary lid 32 and the second step portion 22b.

[0019] In the cask main body 12, a cylindrical end edge 22c that surrounds the secondary lid 32 and appears on the outer side of the cask 11 is formed at the opening 22 of the main body cylinder 21. The surface (the upper surface in FIG. 1) of the end edge 22c is located at a position further on the outer side of the main body cylinder 21 (a higher position in FIG. 1) than the surface of the secondary lid 32, and surrounds the periphery of the secondary lid 32. On the surface of the end edge 22c, a plurality of bolt holes (not shown) for attaching the tertiary lid 33, or the adapter and the transport buffer are provided at intervals in the circumferential direction.

[0020] [Buffer] Next, an example of the configuration of the buffer body 40 according to this embodiment will be described using Figure 2. Figure 2 is a cross-sectional view showing the main part of a radioactive material storage container to which the buffer body is installed.

[0021] As shown in Figure 2, the cask 11 is equipped with a buffer 40. The buffer 40 is attached to the cask 11 when it is transported to a storage facility (in this embodiment, the storage building 90 shown in Figure 3, which will be described later), which is a storage location.

[0022] The buffer 40 is a radial buffer that absorbs impact by deforming in response to predetermined loads applied to the cask 11 in the radial and axial directions. The predetermined loads include, for example, the load of a hypothetical falling object, the load on the cask 11 when it hits the floor upon falling, and the load on the cask 11 when it hits a wall upon moving.

[0023] The buffer body 40 is made of a porous metal such as aluminum, and is deformable by a predetermined load. The buffer body 40 may be formed as an annular shape made of aluminum or the like, with a structure having a plurality of holes that penetrate in the radial direction. The buffer body 40 may have, for example, a support member provided in a hollow shape, and a buffer material arranged and supported inside the support member. The support member is made of a metal plate such as a steel plate, and the buffer material is made of a porous metal such as aluminum. In addition, wood or foamed resin may be used as the buffer material for the buffer body 40.

[0024] The buffer 40 is attached to the end of the cask 11 on the side where the axial lid portion 13 is provided, and to the end of the cask 11 on the side where the axial bottom portion 29 is provided. The buffer 40 of the first embodiment has a disc portion 41 and a cylindrical portion 42. The cylindrical portion 42 is integrally provided on the radially outer side of the disc portion 41.

[0025] The disc portion 41 is positioned along the surface of the tertiary cover 33 that is exposed on the outside of the lid portion 13 at the end of the cask 11 on the side where the axial lid portion 13 is provided. The disc portion 41 is positioned to cover the surface of the tertiary cover 33 and the surface of the edge 22c of the main body 21. The disc portion 41 is fixed to the main body 21 by bolts (not shown) that are attached to bolt holes (not shown) provided on the surface of the main body 21. If an adapter is provided instead of the tertiary cover 33, the disc portion 41 is positioned along the adapter and to cover the surface of the adapter.

[0026] The cylindrical portion 42 is positioned at the end of the cask 11 on the side where the axial lid portion 13 is provided, so as to surround the radially outer edge 22c of the cask body 12. That is, the cylindrical portion 42 is positioned radially outward from the lid portion 13, protrudes radially outward from the cask body 12, and is supported by the disc portion 41 so as to cover the outer circumferential surface of the cask body 12.

[0027] The buffer 40 is also provided at the end of the cask 11 on the side where the axial bottom 29 is located. The disc portion 41 is positioned along the end face of the bottom 29 at the end of the cask 11 on the side where the axial bottom 29 is located. The disc portion 41 is positioned to cover the end face of the bottom 29 and the end face of the main body 21 on the bottom 29 side. The disc portion 41 is fixed to the main body 21 by bolts (not shown) attached to bolt holes (not shown) provided in the bottom 29. The cylindrical portion 42 is positioned at the end of the cask 11 on the side where the axial bottom 29 is located, surrounding the outside of the cask body 12. That is, the cylindrical portion 42 is positioned radially outward from the bottom 29, protrudes radially outward from the cask body 12, and is supported by the disc portion 41 so as to cover the outer circumferential surface of the cask body 12.

[0028] [Storage units and storage buildings] Next, an example of the configuration of the storage unit 50 and the containment building 90 according to the first embodiment will be described using Figures 3 to 5. Figure 3 is a schematic perspective view showing the storage state of the radioactive material storage container held in the storage unit of the first embodiment. Figure 4 is a front view showing the storage unit of the first embodiment. Figure 5 is a side view showing the storage unit of the first embodiment.

[0029] The storage unit 50 is installed between the cask 11, which has been transported to a storage facility (in this embodiment, a storage building 90) that is a storage location and to which the buffer body 40 has been attached, and the storage building 90. The storage unit 50 has protective equipment 60. The storage unit 50 of this embodiment further has a support frame 51.

[0030] The stand 51 is installed on the floor of the storage area or storage facility and, in the first embodiment, holds the cask 11 in a horizontal position. The stand 51 may also hold the cask 11 in a vertical position. The stand 51 has, for example, a base 52 and a support part 53. The base 52 is installed on the floor of the storage area or storage facility. The base 52 is formed in a flat plate shape using, for example, a metal such as carbon steel or concrete as a material. Preferably, the base 52 is provided over an area wider than the projected area of ​​the cask 11 in a plan view. This makes it possible to suppress the unintentional movement of the cask 11 together with the stand 51 during abnormal events such as earthquakes or tornadoes, and prevent casks 11 stored side by side from colliding with each other.

[0031] The support portion 53 is erected from the base 52 and supports the cask body 12 of the cask 11 in a fitted state. The support portion 53 is made of a material such as carbon steel and, in the first embodiment, is formed in multiple columns that extend vertically. The support portion 53 may be provided in an X-shaped column, for example. In the first embodiment, the support portion 53 supports the cask 11 at four locations. In an axial view of the cask 11, the support portion 53 supports the cask 11 by sandwiching one end of the cask 11 in the axial direction with the other end of the cask 11 in the width direction of the cask 11. By being installed on the frame 51, the cask 11 is restricted from moving at least horizontally and downward relative to the frame 51. In addition, the cask 11 is restricted from moving upward relative to the frame 51 by being secured by the trunnion 30 (see Figure 1).

[0032] The protective equipment 60 is located inside the storage building (storage facility) 90 and is installed to cover at least the upper part of the cask 11 with a predetermined gap between them. The protective equipment 60 protects the cask 11 from falling structures if the storage building 90 where the cask 11 is stored collapses due to an earthquake or the like, and also ensures an air passage for heat removal. The protective equipment 60 of the first embodiment has a roof section 61 and a support column section 62.

[0033] The roof portion 61 is positioned to cover at least a portion of the upper part of the cask 11. In the first embodiment, the roof portion 61 is positioned to cover the upper part of the cask 11 and the buffers 40 attached to both ends of the cask 11. In an axial view, the roof portion 61 is provided in an inverted V shape with the central part in the width direction convex upward. The roof portion 61 is not limited to the so-called gable roof shape shown in Figures 3 to 5, and may be a hip roof, pyramidal roof, arch roof, or dome roof, but it is preferable to have a convex part or projection that can destroy falling objects.

[0034] The roof section 61 has ventilation holes 61h that penetrate from above to below the roof section 61. That is, the roof section 61 allows ventilation between the cask 11 side and the ceiling wall side of the storage building 90. Multiple ventilation holes 61h may be provided. The dimensions, shape, and arrangement of the ventilation holes 61h are not limited to the examples shown in Figures 4 and 5. The roof section 61 is formed from a material such as carbon steel, stainless steel, aluminum, or carbon fiber composite material.

[0035] The support column 62 is fixed at its lower end to the frame 51 and supports the roof 61 at its upper end. In the first embodiment, the support column 62 supports the roof 61 at four locations. The space between adjacent support columns 62 is ventilated between the cask 11 side and the side wall side of the storage building 90. The support column 62 is formed from a material such as carbon steel or stainless steel.

[0036] In a nuclear power plant, for example, spent fuel assemblies are stored in the cells 25 of the basket 24 of the main body shell 21 of the cask 11, and sealed by the lid 13. The cask 11 is transported, for example, from the nuclear power plant to a storage facility. When transporting the cask 11 within the power plant premises, a buffer body 40, which is a storage buffer body, is attached, and when transporting it outside the power plant premises, a transport buffer body (not shown) is attached.

[0037] The casks 11, transported to a storage facility (in this embodiment, a storage building 90), are stored horizontally with their central axis O aligned horizontally, as shown in Figures 3 to 5. The casks 11 are stored horizontally with their central axis O aligned horizontally, with the cask body 12 fitted onto a stand 51 installed on the floor. In this case, the casks 11 have storage buffers 40 attached to one side (lid 13 side) and the other side (bottom 29 side) along the central axis O. With the casks 11 fitted onto the stand 51 with the buffers 40 attached, protective equipment 60 is installed around the casks 11.

[0038] In the first embodiment, the storage building 90 stores the casks 11 individually. The storage building 90 is entirely made of concrete walls and has a ceiling wall and a plurality of side walls. The storage building 90 may have an installation floor that covers the ground. The installation floor may be the floor of the storage area where the storage building 90 is installed. The storage building 90 may be constructed by combining a plurality of reinforced concrete panels and joining them together with bolts or the like. With the casks 11 to which the buffer bodies 40 are attached fitted onto the frame 51 and protective equipment 60 installed around the casks 11, a plurality of panels are assembled in the storage building 90 to surround them.

[0039] The storage building 90 has an air intake 91, an exhaust port 92, and an inspection door 93. The air intake 91 is located at the bottom of the side wall. The exhaust port 92 is located at the top of the side wall. The exhaust port 92 may also be located on the ceiling wall. The inspection door 93 is used for internal inspection of the storage building 90 and is located at the bottom of the side wall so as to be openable and closable. The storage building 90 is a dry storage facility that stores casks 11 while naturally cooling them with air.

[0040] In the storage building 90, outside air is drawn in through the intake port 91, naturally cooling the cask 11, and the warmed air rises inside the storage building 90 and is discharged through the exhaust port 92. At this time, the air drawn in through the intake port 91 enters the space between the support columns 62, below the roof section 61 and the outer circumference of the cask 11, rises, exits through the ventilation holes 61h formed in the roof section 61 to the top of the roof section 61, and is discharged through the exhaust port 92.

[0041] The storage facility may also be designed to store multiple casks 11 together. In this case, the casks 11, with the buffer body 40 attached and installed in the storage unit 50, are transported to a predetermined location in the storage facility and stored there.

[0042] In the first embodiment, if structural elements such as the ceiling of the storage facility collapse during an abnormal event such as an earthquake or tornado, the roof section 61 will receive the collapsed structure, suppressing the impact load on the cask 11 and preventing debris from flowing in. In addition, a predetermined gap between the roof section 61 and the cask 11, and the gap between the support columns 62, are provided to ensure an air passage for heat removal.

[0043] [Second Embodiment] [Storage Unit] Next, an example of the configuration of the storage unit 50A according to the second embodiment will be described using Figure 6. Figure 6 is a side view showing the storage unit of the second embodiment. In the second embodiment, components similar to those in the first embodiment are denoted by the same reference numerals and their descriptions are omitted as appropriate.

[0044] The storage unit 50A of the second embodiment includes a frame 51 and a protective device 60A. The protective device 60A is provided to cover at least the upper part of the cask 11 with a predetermined gap between them. The protective device 60A includes a grid section 63 in which a plurality of rod members are combined in a grid pattern. The grid section 63 is arranged to cover at least the upper part of the cask 11. The grid section 63 extends, for example, along the width and axial direction of the cask 11 and is positioned at a predetermined gap from the surface. In the second embodiment, the grid section 63 extends along the circumferential and axial direction of the cask body 12 of the cask 11 and is positioned at a predetermined gap from the surface of the outer cylinder 26.

[0045] The lattice section 63 is attached to the buffers 40 provided at both ends of the cask 11. The lattice section 63 includes a plurality of straight rod members extending linearly along the axial direction of the cask 11, and a plurality of curved rod members extending curvedly around the axial direction of the cask 11, intersecting the straight rod members and connecting them, and is formed as an arch-shaped curved surface overall. The lattice section 63 is provided between the cylindrical portions 42 (see Figure 2) of the buffers 40 provided at both ends of the cask 11. The ends of the straight rod members of the lattice section 63 are each connected to the cylindrical portions 42 of the buffers 40. The plurality of straight rod members are provided at predetermined intervals along the outer circumference of the upper side of the cylindrical portion 42.

[0046] The lattice section 63 is not limited to the dimensions, number, or arrangement of the rod members shown in Figure 6. For example, the spacing between adjacent rod members may be smaller at the top and larger on the sides. Also, in the example shown in Figure 6, the lattice section 63 is provided so that its lower end is at the height of the central axis O, but it may be provided extending below the central axis O, or its lower end may be located above the central axis O. The lattice section 63 is formed from materials such as carbon steel, stainless steel, aluminum, or carbon fiber composite materials. The lattice section 63 is ventilated between the cask 11 side and the ceiling wall side and side wall side of the storage building 90.

[0047] The grid section 63 is attached to the buffer body 40 when the cask 11, to which the buffer body 40 is attached, is fitted onto the frame 51. In the storage building 90, outside air is drawn in through the intake port 91, naturally cooling the cask 11, while the warmed air passes through the grid section 63, rises inside the storage building 90, and is discharged through the exhaust port 92.

[0048] In the second embodiment, if a structure such as the ceiling of the storage facility collapses during an earthquake, the lattice section 63 receives the collapsed structure, suppressing the impact load on the cask 11 and the inflow of rubble. In addition, a predetermined gap between the lattice section 63 and the cask 11, and the gaps between the rod members of the lattice section 63, secure an air passage for heat removal.

[0049] [Third Embodiment] [Storage Unit] Next, an example of the configuration of the storage unit 50B according to the third embodiment will be described using Figure 7. Figure 7 is a side view showing the storage unit of the third embodiment. In the third embodiment, components similar to those in the first embodiment are denoted by the same reference numerals and their descriptions are omitted as appropriate.

[0050] The storage unit 50B of the third embodiment includes a frame 51 and protective equipment 60B. The protective equipment 60B is provided to cover at least the top of the cask 11 with a predetermined gap between them. The protective equipment 60B includes a net 64. The net 64 is fixed to the upper side of the frame 51 and is positioned to surround the top and sides of the cask 11 and the buffer body 40, which are fitted onto the frame 51 with the buffer body 40 attached.

[0051] The enclosure net 64 is not limited to the rectangular shape shown in Figure 7, but may also have a gable roof shape or an arch roof shape. The enclosure net 64 is formed from materials such as carbon steel, stainless steel, aluminum, or carbon fiber composite materials. The enclosure net 64 is ventilated between the cask 11 side and the ceiling wall side and side wall side of the storage building 90.

[0052] The enclosure net 64 is attached to the frame 51 when the cask 11, to which the buffer body 40 is attached, is fitted onto the frame 51. In the storage building 90, outside air is drawn into the storage building 90 through the intake port 91, and a portion of it passes through the enclosure net 64 to the side of the cask 11, naturally cooling the cask 11, while the warmed air passes through the enclosure net 64, rises inside the storage building 90, and is discharged from the exhaust port 92.

[0053] In the third embodiment, if a structure such as the ceiling of the storage facility collapses during an earthquake, the enclosure net 64 catches the collapsed structure, suppressing impact loads on the cask 11 and preventing debris from flowing in. In addition, a predetermined gap between the enclosure net 64 and the cask 11, as well as gaps in the net of the enclosure net 64, ensure an air passage for heat removal.

[0054] [Fourth Embodiment] [Storage Unit] Next, an example of the configuration of the storage unit 50C according to the fourth embodiment will be described using Figure 8. Figure 8 is a front view showing the storage unit of the fourth embodiment. Figure 9 is a side view showing the storage unit of the fourth embodiment. In the fourth embodiment, components similar to those in the first embodiment are denoted by the same reference numerals and their descriptions are omitted as appropriate.

[0055] The storage unit 50C of the fourth embodiment includes a frame 51 and a protective device 60C. The protective device 60C is installed so as to cover at least the upper part of the cask 11 with a predetermined gap between them. The protective device 60C includes a roof section 61 and support sections 62, an exhaust pipe 65, and an air intake pipe 66. Although the depiction of the ventilation holes 61h of the roof section 61 is omitted in Figures 8 and 9, the protective device 60C of the fourth embodiment does not require the roof section 61 to have ventilation holes 61h.

[0056] The exhaust pipe 65 is a pipe that extends from below the roof section 61 to the outside of the storage building 90. The exhaust pipe 65 discharges warmed air from below the roof section 61 towards the outside of the storage building 90. The exhaust pipe 65 is installed by penetrating the ceiling wall of the roof section 61 and the storage building 90. The exhaust pipe 65 is not limited to a configuration that connects to the top of the roof section 61, as shown in Figure 8. Multiple exhaust pipes 65 may be provided, as shown in Figure 9. In addition, the protective equipment 60C may have an exhaust pipe 65A inserted into the exhaust port 92 instead of, or in addition to, the exhaust pipe 65 that penetrates the ceiling wall of the storage building 90. For example, the air drawn in via the intake pipe 66 as described above and warmed up by cooling the cask 11 is discharged to the outside of the storage building 90 via the exhaust pipe 65.

[0057] The air intake pipe 66 is a pipe that is inserted through the air intake port 91 and extends from a position closer to the cask 11 than the support column 62 to the outside of the storage building 90. The air intake pipe 66 supplies outside air from the outside of the storage building 90 toward the area around the cask 11. For example, in the event of an earthquake, if the storage building 90 collapses and rubble flows in, making it impossible to create a sufficient air passage, air can be supplied toward the outer circumference of the cask 11 via the air intake pipe 66 by a blower (not shown). The air intake pipe 66 is formed in a cylindrical shape using a material such as carbon steel, stainless steel, aluminum, or carbon fiber composite material. Multiple air intake pipes 66 may be provided, as shown in Figure 9. The air intake pipe 66 may also be provided so as to penetrate the side wall of the storage building 90.

[0058] In the fourth embodiment, if a structure such as the ceiling of the storage facility collapses during an earthquake, the roof section 61 receives the collapsed structure, suppressing the impact load on the cask 11 and the inflow of rubble. In addition, a predetermined gap between the roof section 61 and the cask 11, and a gap between the support columns 62, secure an air passage for heat removal. Furthermore, air is supplied to the outer circumference of the cask 11 via the air supply pipe 66 by a blower (not shown), thereby creating air circulation. The air heated by the air circulation is then discharged to the outside via the exhaust pipe 65.

[0059] [Other embodiments] Although embodiments of this disclosure have been described above, the embodiments are not limited to those described herein.

[0060] For example, the protective equipment 60, 60A, 60B, and 60C of the first, second, third, and fourth embodiments may be combined with each other. For example, the enclosure net 64 of the third embodiment may be provided inside or outside the roof portion 61 and support portion 62 of the first or fourth embodiment, or between the support portion 62. Also, for example, the lattice portion 63 of the second embodiment may be provided in addition to the roof portion 61 and support portion 62 of the first or fourth embodiment, or the enclosure net 64 of the third embodiment may be provided on top of the lattice portion 63 of the second embodiment.

[0061] Furthermore, the protective equipment 60, 60A, 60B, and 60C do not necessarily have to cover the entire area of ​​the cask 11 in a plan view; they may cover only both ends of the cask body 12, or only the ends having the lid portion 13.

[0062] [Effects of the Embodiment] The storage units 50, 50A, 50B, and 50C described in the embodiment can be understood, for example, as follows.

[0063] The storage units 50, 50A, 50B, and 50C according to the first embodiment are arranged inside a storage facility (storage building 90) for a radioactive material storage container (cask 11) that stores radioactive material inside, and are equipped with protective equipment 60, 60A, 60B, and 60C that cover at least the upper part of the radioactive material storage container with a predetermined gap between them.

[0064] This design ensures that even if structures such as the ceiling of the storage facility collapse during an earthquake, the protective equipment 60, 60A, 60B, and 60C will absorb the impact load on the radioactive material storage container (cask 11) and suppress the inflow of debris. Furthermore, because a predetermined gap is maintained between the protective equipment 60, 60A, 60B, and 60C and the radioactive material storage container, the blockage of the heat-removing air passage can be prevented. In this way, the radioactive material storage container can be protected while heat is being removed.

[0065] The storage units 50, 50A, 50B, and 50C according to the second embodiment are the storage units 50, 50A, 50B, and 50C according to the first embodiment, further comprising a frame 51 that is located inside the storage facility (storage building 90) and holds radioactive material storage containers.

[0066] This allows the radioactive material storage container (cask 11) to be held in a stable position.

[0067] The storage units 50, 50C according to the third embodiment are storage units 50, 50C according to the first or second embodiment, wherein the protective equipment 60, 60C includes a roof portion 61 that covers at least the upper part of the radioactive material storage container (cask 11) with a predetermined gap between it and the roof portion 61, and a support portion 62 whose lower end is fixedly provided and whose upper end supports the roof portion 61.

[0068] This allows the roof section 61 to receive the impact load on the radioactive material storage container (cask 11) and suppress the inflow of rubble. In addition, a predetermined gap is left between the roof section 61 and the radioactive material storage container, and the roof section 61 is supported by the support columns 62, which prevents the air passage for heat removal from being blocked.

[0069] The storage units 50, 50C according to the fourth embodiment are the storage units 50, 50C according to the third embodiment, wherein the roof portion 61 has ventilation holes 61h that penetrate the upper and lower parts of the roof portion 61.

[0070] This allows the air that has been naturally cooled and warmed by the radioactive material storage container (cask 11) to escape upwards and be exhausted, rather than becoming trapped inside the roof section 61.

[0071] The storage units 50, 50C according to the fifth embodiment are storage units 50, 50C according to the third or fourth embodiment, wherein the roof portion 61 has a convex portion or projection formed in an upward convex shape.

[0072] This allows the collapsed structure to be destroyed by the convex or protruding parts. As a result, the size of the falling structure is reduced, thus suppressing the impact load on the radioactive material storage container. For example, when the radioactive material storage container (cask 11) is stored with the buffer body 40 attached so as to surround its radially outer side, the buffer body 40 can support the small, broken pieces of the structure, thereby suppressing the impact load on the radioactive material storage container.

[0073] The storage unit 50C according to the sixth embodiment is a storage unit 50C according to any one of the third to fifth embodiments, further comprising an exhaust pipe 65 that penetrates the roof 61 and extends from below the roof 61 to the outside of the storage facility (storage building 90), and discharges air from below the roof 61 toward the outside of the storage facility.

[0074] This allows the air that has been naturally cooled and warmed by the radioactive material storage container (cask 11) to be exhausted to the outside of the storage facility (storage building 90) without becoming trapped inside the roof section 61.

[0075] The storage unit 50C according to the seventh embodiment is a storage unit 50C according to any one of the first to sixth embodiments, and further comprises an air supply pipe 66 that extends from a position closer to the radioactive material storage container (cask 11) than the support column 62 to the outside of the storage facility (storage building 90) and supplies outside air toward the periphery of the radioactive material storage container.

[0076] This allows, for example, in the event of an earthquake, if the storage facility (storage building 90) collapses and debris flows in, preventing adequate airflow, air can be supplied to the outer periphery of the radioactive material storage container (cask 11) via the air intake pipe 66 using a blower (not shown). In other words, an airflow path can be secured, allowing the radioactive material storage container to be deheated.

[0077] The storage unit 50A according to the eighth embodiment is a storage unit 50A according to any one of the first to seventh embodiments, wherein the protective equipment 60A has a grid section 63 in which a plurality of rod members are arranged in a grid pattern so as to cover at least the upper part of the radioactive material storage container (cask 11) with a predetermined gap between them.

[0078] As a result, the lattice section 63 receives the impact load on the radioactive material storage container (cask 11) and suppresses the inflow of large debris. In addition, a predetermined gap is left between the lattice section 63 and the radioactive material storage container, and since ventilation is possible between the rod members of the lattice section 63, it is possible to prevent the air passage for heat removal from being blocked.

[0079] The storage unit 50A according to the ninth embodiment is the storage unit 50A according to the eighth embodiment, wherein the grid portion 63 extends along the axial direction of the radioactive material storage container (cask 11) and is positioned at a predetermined gap from the surface.

[0080] This prevents collapsed structures from falling onto the main body 21 of the radioactive material storage container (cask 11).

[0081] The storage unit 50A according to the tenth embodiment is a storage unit 50A according to either the eighth embodiment or the ninth embodiment, wherein the radioactive material storage container (cask 11) has buffer bodies 40 attached to each of its axial ends, the buffer bodies 40 are arranged to surround the radially outer side of the radioactive material storage container, and the grid portion 63 is attached to the buffer bodies 40.

[0082] As a result, even if the radioactive material storage container (cask 11) moves along with the support frame 51 or falls off the support frame 51, for example, during an earthquake, the grid section 63 moves along with the buffer body 40 provided on the radioactive material storage container, thereby preventing the collapsed structure from falling onto the main body 21 of the radioactive material storage container.

[0083] The storage unit 50B according to the 11th embodiment is a storage unit 50B according to any one of the first to tenth embodiments, wherein the protective equipment 60B has a net enclosure 64 that covers at least the upper part of the radioactive material storage container (cask 11) with a predetermined gap between it and the container.

[0084] This allows the surrounding net 64 to receive the impact load on the radioactive material storage container (cask 11) and suppress the inflow of rubble. In addition, a predetermined gap is left between the surrounding net 64 and the radioactive material storage container, and since the surrounding net 64 is ventilated through the gaps in the net, it is possible to prevent the air passage for heat removal from being blocked. [Explanation of Symbols]

[0085] 11 Casks 12 Cask body 13 Lid 40 Buffer 50, 50A, 50B, 50C storage units 51. Stand 60, 60A, 60B, 60C protective equipment 61 Roof section 61h ventilation holes 62 Pillar section 63 Lattice section 64 Enclosure net 65, 65A exhaust stack 66 Air intake cylinder 90. Storage building (storage facility)

Claims

1. The protective equipment is provided to be placed inside a storage facility for a radioactive material storage container that contains radioactive material, and is installed to cover at least the upper part of the radioactive material storage container with a predetermined gap between it and the container. Storage unit.

2. The storage facility is further equipped with a frame for holding the radioactive material storage container, which is located inside the storage facility. The storage unit according to claim 1.

3. The aforementioned protective equipment is A roof section that covers at least the upper part of the radioactive material storage container with a predetermined gap between it and the container, A support column whose lower end is fixedly provided and whose upper end supports the roof portion, Having, The storage unit according to claim 1.

4. The roof section has ventilation holes that penetrate the upper and lower parts of the roof section. The storage unit according to claim 3.

5. The roof portion has a convex portion or projection formed in a convex shape upwards. The storage unit according to claim 3.

6. The system further includes an exhaust pipe that penetrates the roof and extends from below the roof to the outside of the storage facility, and discharges air from below the roof towards the outside of the storage facility. The storage unit according to claim 3.

7. The facility further includes an air intake pipe that extends from a position close to the radioactive material storage container from the support column to the outside of the storage facility, and supplies outside air towards the periphery of the radioactive material storage container. The storage unit according to claim 3.

8. The aforementioned protective equipment is The radioactive material storage container has a grid section in which multiple rod members are arranged in a grid pattern so as to cover at least the upper part with a predetermined gap between them, The storage unit according to claim 1.

9. The grid portion extends along the axial direction of the radioactive material storage container and is positioned at a predetermined gap from the surface. The storage unit according to claim 8.

10. The aforementioned radioactive material storage container has buffer bodies attached to each of its axial ends. The buffer body is arranged to surround the radially outer side of the radioactive material storage container. The grid portion is attached to the buffer body. The storage unit according to claim 9.

11. The aforementioned protective equipment is The aforementioned radioactive material storage container has a protective net that covers at least the upper part with a predetermined gap between it and the container. The storage unit according to claim 1.

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