JP7506041B2 - Buffer for radioactive material storage container - Google Patents

Description

The present invention relates to a buffer body that is attached to a radioactive material storage container.

One example of technology related to the above-mentioned buffer is described in Patent Document 1. Patent Document 1 describes a buffer that has a core material in which multiple hollow materials are bundled together. The hollow materials are made of a metal material or a ceramic material.

JP 2020-173206 A

The buffer described in Patent Document 1 is a buffer that is attached to a radioactive material storage container during transportation. In the case of a transport container, a design requirement is a 9m fall event in the event of an accident. In that case, the buffer is required to have a large buffering performance (large deformation). However, if a radioactive material storage container is stored horizontally in a storage facility, the fall height is about 2 to 3 m. In this case, the buffer's buffering performance does not need to be as large as that of a buffer that is attached during transportation. Also, since it is stored in a horizontal state, the fall of the radioactive material storage container is limited to a horizontal fall. Therefore, it is possible to design a buffer with a simpler structure than a buffer that is attached during transportation, which has test conditions for not only horizontal falls but also vertical falls and corner falls.

The object of the present invention is to provide a buffer with a simple structure that can adequately absorb the impact energy when dropped from a horizontally stored state onto the floor.

The buffer disclosed in this application is a buffer installed at the axial end of a radioactive material storage container stored in a horizontal position, and includes multiple buffer members formed of a metal material, each of which is shaped to protrude radially outward from the radioactive material storage container, with a space provided between adjacent buffer members.

Because metal materials are inorganic materials, buffer members made of metal materials are less susceptible to deterioration due to radiation and heat. Furthermore, by providing spaces between adjacent buffer members, the buffer body can be made lighter while adequately absorbing the impact energy during a fall, mainly through buckling deformation. The buffer members have a simple structure in that they protrude radially outward from the radioactive material storage container, and there is a space between adjacent buffer members.

The device may further include a cylindrical inner cover member that is fitted into the axial end, and the buffer member may be attached to the outer circumferential surface of the inner cover member in a position that protrudes outward in the radial direction.

This configuration makes it easy to install a buffer body equipped with a buffer member at the axial end of the radioactive material storage container.

A plate member that is abutted against and fixed to the axial end face of the radioactive material storage container may also be attached to the inner peripheral surface of the inner cover member.

This configuration makes it easy to position the buffer body. It also makes it easy to install the buffer body.

The inner cover member may also have a first inner cover portion that is fitted into the axial end portion, and a second inner cover portion that extends from the first inner cover portion outward in the axial direction of the radioactive material storage container beyond the plate member.

The cushioning member is attached to the outer peripheral surface of the inner cover member. With the above configuration, it is possible to ensure sufficient mounting space for the cushioning member. As a result, there is greater design freedom in terms of the number of cushioning members, mounting pitch, dimensions, etc., making it easier to design the cushioning body.

A reinforcing member that supports the second inner cover portion may be attached to the inner peripheral surface of the second inner cover portion.

This configuration makes it difficult for the second inner cover part to bend. Therefore, the cushioning member attached to the outer peripheral surface of the second inner cover part is more likely to buckle and deform as designed. As a result, impact energy can be absorbed more appropriately.

The buffer members may also be ring-shaped plates spaced apart from each other in the axial direction of the radioactive material storage container.

This configuration makes it easier to attach the cushioning member than if it were a pipe or rod-shaped member.

The cushioning member may also be pipe-shaped or rod-shaped.

This configuration allows greater freedom in designing the number of cushioning members, their mounting pitch, and their dimensions, making it easier to design the cushioning body. It also makes it easier to procure materials for the cushioning members.

The buffer member may be formed from a rectangular plate material having multiple notches partway through, and the portions between adjacent notches may be twisted to form multiple elongated portions in the buffer member that protrude outward in the radial direction and are spaced apart from one another, and the buffer members may be arranged at intervals from one another in the circumferential direction of the radioactive material storage container.

When the cushioning member is made of the rectangular plate material, the end face opposite the side on which the multiple elongated portions are formed is linear. This makes it easy to attach the cushioning member.

The buffer member may also include a plurality of first buffer members and a plurality of second buffer members that protrude radially outwardly further than the first buffer members.

With this configuration, the density is low on the outside and high on the inside. This makes it possible to reduce the peak of the initial impact load when the cushion hits the floor. In addition, the cushion with the above configuration absorbs the impact energy in the part with high density on the inside once the cushion has been deformed to a certain extent. Therefore, in the later stages of hitting the floor, the impact energy can be absorbed with a small amount of deformation.

The device may further include an outer cover member that covers the cushioning member.

This configuration allows for stable shock absorption performance.

The present invention provides a buffer with a simple structure that can adequately absorb the impact energy when dropped from a horizontally stored state onto the floor.

FIG. 2 is a side view of a radioactive material storage container in which a buffer body according to the first embodiment of the present invention is installed. 2 is a cross-sectional view of the buffer shown in FIG. 1 along line AA. FIG. 2 is an enlarged view of part B shown in FIG. FIG. 11 is a side view of a radioactive substance storage container in which a buffer body according to a second embodiment of the present invention is installed. 5 is a cross-sectional view of the buffer shown in FIG. 4 along the line CC. 5 is a diagram for explaining the cushioning member shown in FIG. 4 . FIG. FIG. 13 is a side view of a radioactive material storage container in which a buffer body according to a third embodiment of the present invention is installed. 8 is a cross-sectional view of the buffer shown in FIG. 7 along the line E-E. FIG. 13 is a side view of a radioactive material storage container in which a buffer body according to a fourth embodiment of the present invention is installed. 10 is a cross-sectional view of the buffer body shown in FIG. 9 taken along the line FF. FIG. 13 is a side view of a radioactive material storage container in which a buffer body according to a fifth embodiment of the present invention is installed. 12 is a cross-sectional view of the buffer body shown in FIG. 11 taken along the line G-G.

The following describes the embodiment of the present invention with reference to the drawings.

A radioactive material storage container 1 is used to contain and store radioactive material such as spent fuel, and is called a cask. The radioactive material storage container 1 containing radioactive material may be stored either vertically or horizontally within a storage facility. The state of the radioactive material storage container 1 when stored horizontally is shown in Figures 1 and 4. The horizontal state refers to a state in which the radioactive material storage container 1 is placed with its axial direction Z horizontal. A number of trunnions 2 for handling and installation on a storage rack are attached to the outer periphery of the radioactive material storage container 1. The radioactive material storage container 1 is a cylindrical container.

When the radioactive material storage container 1 is stored in a horizontal position, if it falls, it will fall from a height of about 2 to 3 m. When the radioactive material storage container 1 is stored in a horizontal position, it will fall horizontally. A horizontal fall means that the axial direction Z of the radioactive material storage container 1 falls while being nearly horizontal. Even when the radioactive material storage container 1 is transported in a horizontal position within a storage facility, it will fall from a height of about 2 to 3 m, and will fall horizontally. A buffer 3 is installed at the axial direction Z end of the radioactive material storage container 1 to protect the radioactive material storage container 1 from impact when it falls from a horizontal position.

First Embodiment
1 to 3 are diagrams for explaining the buffer body 3 of the first embodiment. In Fig. 1, the left end of the radioactive material storage container 1 is the upper part (lid side) of the radioactive material storage container 1, and the right end of the radioactive material storage container 1 is the lower part (bottom side) of the radioactive material storage container 1. The buffer bodies 3 are installed at the upper and lower parts of the radioactive material storage container 1. The buffer body 3 installed at the upper part of the radioactive material storage container 1 and the buffer body 3 installed at the lower part of the radioactive material storage container 1 have the same structure.

The buffer 3 includes multiple buffer members 4 that absorb impact energy, a cylindrical inner cover member 5, and a plate member 6 that abuts against the axial Z end face of the radioactive material storage container 1.

The buffer members 4 are shaped to protrude outward in the radial direction of the radioactive material storage container 1. In this embodiment, the multiple buffer members 4 are multiple pipe-shaped objects (e.g., pipes) arranged radially. Instead of pipe-shaped objects, the buffer members 4 may be rod-shaped objects (e.g., rods). Pipe-shaped objects and rod-shaped objects are easy to prepare, so if the buffer members 4 are pipe-shaped or rod-shaped objects, the buffer members 4 can be easily prepared. A space is provided between adjacent buffer members 4 so that the buffer members 4 are easily buckled. The buffer members 4 are made of a metal material. The metal material is preferably a highly ductile material that is easily buckled. The metal material is, for example, an aluminum alloy, a copper alloy, stainless steel, or carbon steel. Since the metal material is an inorganic material, the buffer members 4 made of a metal material are not easily deteriorated by radiation and heat. In addition, the use of a metal material has the following accompanying effects. Conventionally, wood has been used as the buffer material used for the radioactive material storage container 1. Because wood is a natural material, it is difficult to ensure uniformity in quality, such as strength, density, and moisture content, which can lead to poor yields. Using industrial metal materials for the cushioning member 4 makes quality control easier.

The design of the buffer body 3 is carried out based on a balance with the shock absorption energy, taking into account parameters such as the mounting pitch (spacing), material, and cross-sectional dimensions of the buffer members 4. The buffer members 4 protrude radially outward from the radioactive material storage container 1, and have a simple structure in which a space is provided between adjacent buffer members 4. Furthermore, by providing a space between adjacent buffer members 4, the weight of the buffer body 3 can be reduced.

Let us assume that the radioactive material storage container 1 stored horizontally is dropped. At this time, the buffer member 4 collides with the floor surface, and the buffer member 4 mainly undergoes buckling deformation (crushes). This buckling deformation allows the buffer member 4 to appropriately absorb the impact energy caused by the collision with the floor surface. By absorbing the impact energy, the impact acceleration is mitigated. As a result, the sealing performance of the lid of the radioactive material storage container 1 is maintained.

The inner cover member 5 is a member that holds the multiple buffer members 4. The multiple buffer members 4 are attached radially to the outer circumferential surface of the inner cover member 5 in a position in which they protrude radially outward from the radioactive material storage container 1. The inner cover member 5 is fitted into the axial Z end of the radioactive material storage container 1. The inner diameter of the inner cover member 5 is slightly larger than the outer diameter of the axial Z end of the radioactive material storage container 1. Since the buffer body 3 is equipped with the inner cover member 5, an operator can easily install the buffer body 3 equipped with the buffer members 4 at the axial Z end of the radioactive material storage container 1.

As shown by the reference numerals in FIG. 3, the inner cover member 5 is composed of a first inner cover part 5a and a second inner cover part 5b. The first inner cover part 5a is a part that is fitted into the axial direction Z end part of the radioactive material storage container 1. The second inner cover part 5b is a part that extends from the first inner cover part 5a outward in the axial direction Z of the radioactive material storage container 1 beyond the plate member 6. The inner cover member 5 is formed of a metal material. The metal material is, for example, an aluminum alloy, a copper alloy, stainless steel, or carbon steel. The buffer member 4 is attached to the outer circumferential surface of the inner cover member 5. When the inner cover member 5 is configured as described above, sufficient mounting space for the buffer member 4 can be secured. As a result, the design freedom of the quantity, mounting pitch, and dimensions of the buffer member 4 is increased, making it easier to design the buffer body 3.

The plate member 6 is attached to the inner peripheral surface of the inner cover member 5. The plate member 6 is a disk-shaped member. The diameter of the plate member 6 is approximately the same as the inner diameter of the inner cover member 5. The plate member 6 is detachably fixed to the axial Z end face of the radioactive material storage container 1 by a plurality of bolts 7. The plate member 6 is made of a metal material. The metal material is, for example, an aluminum alloy, a copper alloy, stainless steel, or carbon steel. By attaching the plate member 6 to the inner peripheral surface of the inner cover member 5, an operator can easily position the buffer body 3 relative to the radioactive material storage container 1. In addition, the buffer body 3 can be easily installed.

When the buffer 3 is installed at the axial Z end of the radioactive material storage container 1, the inside of the second inner cover part 5b constituting the inner cover member 5 becomes hollow. A reinforcing member 8 supporting the second inner cover part 5b is arranged in this hollow part. The reinforcing member 8 in this embodiment has a cylindrical member 8a and multiple plate-shaped rib members 8b. The cylindrical member 8a is attached to the center of the wide surface of the plate member 6. The multiple rib members 8b are installed radially between the second inner cover part 5b and the cylindrical member 8a. One end face of the rib member 8b in the longitudinal direction is attached to the inner peripheral surface of the second inner cover part 5b, and the other end face is attached to the outer peripheral surface of the cylindrical member 8a. The surface of the rib member 8b along the longitudinal direction is attached to the plate member 6. The reinforcing member 8 is formed of a metal material. The metal material is, for example, an aluminum alloy, a copper alloy, stainless steel, or carbon steel.

By disposing the reinforcing member 8, the second inner cover portion 5b is less likely to bend. Therefore, the buffer member 4 attached to the outer peripheral surface of the second inner cover portion 5b is more likely to buckle and deform as designed when colliding with the floor surface. As a result, impact energy can be absorbed more appropriately. Note that the configuration of the reinforcing member 8 is not limited to the above configuration. The reinforcing member 8 may be configured to support the second inner cover portion 5b from the inside.

The hollow portion is covered with an end cover member 9 to prevent rainwater and the like from entering the hollow portion. In this embodiment, the end cover member 9 is composed of a ring-shaped cover member 9a and a disk-shaped cover member 9b inside it. The end cover member 9 is made of a metal material. The metal material is, for example, an aluminum alloy, a copper alloy, stainless steel, or carbon steel. Note that the configuration of the end cover member 9 is not limited to the above configuration. Also, the end cover member 9 may be omitted.

Second Embodiment
4 to 6 are diagrams for explaining the buffer body 3 of the second embodiment. The difference between the buffer body 3 of the first embodiment and the buffer body 3 of the second embodiment is the configuration of the buffer member. The configuration other than the buffer member is the same between the buffer body 3 of the first embodiment and the buffer body 3 of the second embodiment. The configuration of the buffer member 10 included in the buffer body 3 of the second embodiment is as follows.

Figure 6 is a diagram for explaining the buffer member 10 shown in Figure 4. The upper diagram in Figure 6 is a diagram showing the intermediate member 11 (in the middle of production) of the buffer member 10. The intermediate member 11 is a rectangular plate material having a plurality of slits 11a halfway through. The plurality of slits 11a are, for example, made at a relatively fine pitch (spacing) (about 30 mm pitch). The pitch (spacing) of the slits 11a is not particularly limited. By twisting the portion between the adjacent slits, as shown in the lower diagram in Figure 6, a plurality of elongated portions 12 that protrude outward in the radial direction of the radioactive material storage container 1 and are spaced apart from each other are formed. The elongated portions 12 are the portions that absorb impact energy. In order to increase the area occupied by the elongated portions 12 in the buffer member 10, it is desirable that the slits 11a are long. In addition, it is desirable that the portion to be twisted is the root portion of the portion between the slits 11a. In this embodiment, the base portion of the portion between the slits is twisted 90 degrees to form the elongated portion 12. The twist angle is not limited to 90 degrees.

The multiple buffer members 10, each of which has multiple elongated portions 12, are arranged at intervals from one another in the circumferential direction of the radioactive material storage container 1. The multiple buffer members 10 are attached to the outer circumferential surface of the inner cover member 5 in a position in which they protrude outward in the radial direction of the radioactive material storage container 1. Here, the end face 17 of the buffer member 10 on the side where the notch 11a is not made is linear. In addition, the outer circumferential surface of the inner cover member 5 is linear in the axial direction of the inner cover member 5. Since the linear shapes are butted together and fixed by welding or the like, workers can easily attach the buffer members 10 to the inner cover member 5.

The buffer member 10 is formed of a metal material, similar to the buffer member 4 of the first embodiment. The metal material is preferably a highly ductile material that is easily subject to buckling deformation. Examples of the metal material include an aluminum alloy, a copper alloy, stainless steel, or carbon steel.

Suppose that the radioactive material storage container 1 stored in a horizontal position is dropped. At this time, the elongated portion 12 of the buffer member 10 collides with the floor surface, and the elongated portion 12 mainly buckles (is crushed). This buckling deformation allows the buffer member 10 (elongated portion 12) to appropriately absorb the impact energy caused by the collision with the floor surface. The absorption of the impact energy reduces the impact acceleration. As a result, the sealing performance of the lid of the radioactive material storage container 1 is maintained.

Third Embodiment
7 and 8 are diagrams for explaining the buffer 3 of the third embodiment. The difference between the buffer 3 of the first embodiment and the buffer 3 of the third embodiment is that the buffer 3 of the third embodiment further includes an outer cover member 13 that covers the buffer member 4. The buffer 3 of the third embodiment is obtained by attaching the outer cover member 13 that covers the buffer member 4 to the buffer 3 of the first embodiment. The buffer members 4 are mutually constrained by the outer cover member 13. When the buffer members 4 are constrained by each other, the buckling deformation of the buffer members 4 is stabilized, so that the shock absorbing performance of the buffer members 4 can be stabilized. As shown in FIG. 7 and FIG. 8, the outer cover member 13 is, for example, cylindrical. The outer cover member 13 is formed of a metal material. The metal material is, for example, an aluminum alloy, a copper alloy, stainless steel, or carbon steel.

Fourth Embodiment
9 and 10 are diagrams for explaining the buffer body 3 of the fourth embodiment. The difference between the buffer body 3 of the first embodiment and the buffer body 3 of the fourth embodiment is the configuration of the buffer member. The configuration other than the buffer member is the same between the buffer body 3 of the first embodiment and the buffer body 3 of the fourth embodiment. The configuration of the buffer member 14 included in the buffer body 3 of the fourth embodiment is as follows.

The buffer member 14 is composed of a plurality of first buffer members 15 and a plurality of second buffer members 16. The second buffer members 16 protrude further outward in the radial direction of the radioactive material storage container 1 than the first buffer members 15. With this configuration, the installation area of the buffer members 14 when placed on the floor is smaller than when all the buffer members have the same length (height). The first buffer member 15 is a ring-shaped plate with a height H1. The second buffer member 16 is a ring-shaped plate with a height H2. H2>H1. The first buffer member 15 may be formed into a ring shape from a single plate material, or may be formed into a ring shape by connecting arc-shaped plates together. The same applies to the second buffer member 16. The second buffer member 16 may be formed into a ring shape from a single plate material, or may be formed into a ring shape by connecting arc-shaped plates together.

The first buffer member 15 and the second buffer member 16 are both ring-shaped plates. By using ring-shaped plates, the worker can install the buffer member 14 more easily than in the first embodiment, where the buffer member 4 is a pipe-shaped or rod-shaped object.

In this embodiment, the first buffer members 15 of height H1 and the second buffer members 16 of height H2 are alternately arranged at intervals in the axial direction Z of the radioactive material storage container 1. Note that instead of alternately arranging the first buffer members 15 and the second buffer members 16 one by one as in this embodiment, the first buffer members 15 and the second buffer members 16 may be alternately arranged every two or more members.

The buffer member 14 can mitigate the initial peak of the impact load when it is dropped and landed on the floor surface. At the moment of landing, when the buffer member 14 starts to buckle, a peak of the impact load occurs instantaneously, and a peak of the impact acceleration occurs accordingly. At that time, since the installation area of the buffer member 14 that is landed on the floor is small, the buffer member 14 is easily buckled and deformed when it is landed on the floor, and the peak of the impact acceleration can be mitigated. After that, when a certain degree of deformation occurs, the second-stage buffer member part with high material density (the part close to the inner cover member 5 where the first buffer member 15 and the second buffer member 16 are alternated in the axial direction Z) absorbs the impact energy, so that it is possible to absorb the drop energy of the entire radioactive material storage container 1 with a limited amount of deformation. In other words, if the part of the radioactive material storage container 1 that protrudes outward in the radial direction is too small, the impact acceleration can be mitigated, but a large amount of deformation is required, and there is a possibility that the radioactive material storage container 1 will collide with the floor surface. However, this can be avoided by making the part that protrudes radially outward from the radioactive material storage container 1, like the buffer member 14, into a protruding part with two levels of different density.

The buffer members 14 (first buffer member 15, second buffer member 16) are formed of a metal material, similar to the buffer member 4 of the first embodiment. The metal material is preferably a highly ductile material that is easily subject to buckling deformation. Examples of the metal material include an aluminum alloy, a copper alloy, stainless steel, or carbon steel.

Fifth Embodiment
11 and 12 are diagrams for explaining the buffer body 3 of the fifth embodiment. The difference between the buffer body 3 of the first embodiment and the buffer body 3 of the fifth embodiment is the configuration of the buffer member. The configuration other than the buffer member is the same between the buffer body 3 of the first embodiment and the buffer body 3 of the fifth embodiment. The configuration of the buffer member 17 included in the buffer body 3 of the fifth embodiment is as follows.

The buffer members 17 are ring-shaped plates that are spaced apart from one another in the axial direction Z of the radioactive material storage container 1. Unlike the fourth embodiment, the heights H of the multiple buffer members 17 are all made equal. The buffer members 17 may be formed into a ring shape from a single plate material, or may be formed into a ring shape by connecting arc-shaped plates together.

Because the buffer member 17 is a ring-shaped plate, workers can install the buffer member 17 more easily than in the first embodiment, when the buffer member 4 is a pipe or rod-shaped object.

The buffer member 17 is made of a metal material, similar to the buffer member 4 of the first embodiment. The metal material is preferably a highly ductile material that is easily subject to buckling deformation. Examples of the metal material include an aluminum alloy, a copper alloy, stainless steel, or carbon steel.

In this embodiment, the multiple buffer members 17 are covered by the outer cover member 13, as in the third embodiment. The buffer members 17 are mutually constrained by the outer cover member 13. By constraining the buffer members 17, the buckling deformation of the buffer members 17 is stabilized, and the shock absorbing performance of the buffer members 17 can be stabilized. The outer cover member 13 is, for example, cylindrical. The outer cover member 13 is formed of a metal material. The metal material is, for example, an aluminum alloy, a copper alloy, stainless steel, or carbon steel. The outer cover member 13 may be omitted.

In addition, multiple plate materials 18 are installed between adjacent buffer members 17. As shown in FIG. 12, the plate materials 18 are arranged at intervals from each other in the circumferential direction of the radioactive material storage container 1. The buffer members 17 are restrained by the plate materials 18 in addition to the outer cover member 13. With this configuration, the shock absorbing performance of the buffer members 17 can be made more stable. The plate materials 18 are made of a metal material. The metal material is, for example, an aluminum alloy, a copper alloy, stainless steel, or carbon steel. The plate materials 18 may be omitted.

The present invention is not limited to the above-described embodiments. It is possible to combine the various configurations of the above-described embodiments as appropriate, and to make various modifications to the above-described embodiments.

For example, the above embodiment can be modified as follows:

The buffer member 10 (elongated portion 12) constituting the buffer 3 of the second embodiment shown in Figures 4 to 6 may be covered with an outer cover member 13, as in the buffer 3 of the third embodiment shown in Figures 7 and 8. Similarly, the buffer member 14 (second buffer member 16) constituting the buffer 3 of the fourth embodiment shown in Figures 9 and 10 may be covered with an outer cover member 13.

The buffer member 14 constituting the buffer 3 of the fourth embodiment shown in Figs. 9 and 10 is a two-stage buffer member 14 that has different deformation amounts under the same impact load, consisting of a plurality of first buffer members 15 and a plurality of second buffer members 16 of different heights. A three-stage buffer member may be formed by further adding a plurality of ring-shaped plates of different heights to the first buffer members 15 and the second buffer members 16. Furthermore, a buffer member may be formed with four or more stages.

The pipe-shaped or rod-shaped buffer member such as the buffer member 4 constituting the buffer body 3 of the first embodiment shown in Figures 1 to 3 may be a buffer member having two stages such as the buffer member 14, or may be a buffer member having three or more stages. By varying the length of the pipe-shaped members (or rod-shaped members), a buffer member having two or more stages can be formed. Similarly, the buffer member 10 constituting the buffer body 3 of the second embodiment shown in Figures 4 to 6 may be a buffer member having two or more stages such as the buffer member 14.

1: Radioactive material storage container 3: Buffer body 4, 10, 14, 17: Buffer member 5: Inner cover member 5a: First inner cover part 5b: Second inner cover part 6: Plate member 8: Reinforcing member 11: Intermediate member (plate material)
11a: slit 12: elongated portion 13: outer cover member 15: first cushioning member (cushioning member)
16: Second cushioning member (cushioning member)
Z: Axial direction

Claims (10)

A buffer body installed at an axial end of a radioactive material storage container stored in a horizontal position,
A plurality of buffer members formed of a metal material are provided,
The buffer member is shaped to protrude outward in a radial direction of the radioactive material storage container,
A space is provided between adjacent buffer members ,
The buffer member is formed from a rectangular plate material having a plurality of slits halfway through the plate,
A portion between adjacent ones of the slits is twisted to form a plurality of elongated portions in the buffer member, the elongated portions protruding outward in the radial direction and spaced apart from one another,
The buffer members are arranged at intervals from each other in the circumferential direction of the radioactive material storage container.
A buffer for radioactive material storage containers. A buffer body installed at an axial end of a radioactive material storage container stored in a horizontal position,
A plurality of buffer members formed of a metal material are provided,
The buffer member is shaped to protrude outward in a radial direction of the radioactive material storage container,
A space is provided between adjacent buffer members ,
The buffer member includes a plurality of first buffer members and a plurality of second buffer members that protrude outward in the radial direction longer than the first buffer members.
A buffer for radioactive material storage containers. The buffer for the radioactive material storage container according to claim 1 or 2 ,
Further, a cylindrical inner cover member is provided which is fitted to the axial end portion,
The buffer member is attached to an outer circumferential surface of the inner cover member so as to protrude outward in the radial direction.
A buffer for radioactive material storage containers. The buffer for the radioactive material storage container according to claim 3 ,
A plate member is attached to an inner circumferential surface of the inner cover member so as to be in contact with and fixed to an axial end surface of the radioactive material storage container.
A buffer for radioactive material storage containers. The buffer for the radioactive material storage container according to claim 4 ,
The inner cover member is
A first inner cover portion fitted to the axial end portion;
A second inner cover portion extends from the first inner cover portion outward in the axial direction of the radioactive material storage container beyond the plate member.
A buffer for radioactive material storage containers. The buffer for the radioactive material storage container according to claim 5 ,
A reinforcing member for supporting the second inner cover portion is attached to an inner circumferential surface of the second inner cover portion.
A buffer for radioactive material storage containers. The buffer for the radioactive material storage container according to claim 2 ,
The buffer members are ring-shaped plates arranged at intervals in the axial direction of the radioactive material storage container.
A buffer for radioactive material storage containers. The buffer for the radioactive material storage container according to claim 2 ,
The buffer member is a pipe-shaped or rod-shaped member.
A buffer for radioactive material storage containers. The buffer for the radioactive material storage container according to claim 1 ,
The buffer member includes a plurality of first buffer members and a plurality of second buffer members that protrude outward in the radial direction longer than the first buffer members.
A buffer for radioactive material storage containers. The buffer for a radioactive material storage container according to any one of claims 1 to 9,
Further comprising an outer cover member for covering the cushioning member.
A buffer for radioactive material storage containers.

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