Buffer body and storage device for radioactive material storage container

Abstract

To simply suppress the rise in temperature of a buffer material used for a buffer main body.SOLUTION: A buffer provided herein is attached to a radioactive material storage container installable on a pedestal and comprises a main body and a first anisotropic heat transfer material. The main body has a recess engageable with an edge of the radioactive material storage container. The first anisotropic heat transfer material is provided to at least partially cover the recess of the main body and is configured such that a thermal conductivity thereof in an in-plane direction is greater than that in an out-of-plane direction.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present disclosure relates to a buffer body and a storage device for a radioactive material storage container. [Background technology]

[0002] Radioactive material storage containers, commonly called casks, are known as containers for storing radioactive materials (such as spent nuclear fuel) handled in nuclear reactors and the like. Radioactive material storage containers have a heavy main body to provide good shielding properties for radioactive materials from the outside. Since such radioactive material storage containers are heavy, when they are moved, they are hoisted and transported by engaging a transport device such as a crane with a cylindrical structure (such as a trunnion) that protrudes from the outside of the main body.

[0003] A shock absorber may be attached to the radioactive material storage container in order to absorb shock when the container is dropped during transportation or is exposed to external impact. This type of shock absorber is made of a material having shock absorbing properties, such as wood. For example, Patent Document 1 discloses a shock absorber made of a porous material as an example of a shock absorber. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2021-4831 Summary of the Invention [Problem to be solved by the invention]

[0005] The above-mentioned buffer body is attached to the container body mainly to absorb shock during transportation, and therefore, conventionally, it is often removed from the container body when the container body is installed at the storage position after transportation is completed. In response to this, there is a need to store the radioactive material with the buffer body attached to the container body in order to absorb shock caused by falling or tipping over during an earthquake or contact with the outside during storage. In this case, since the buffer body is attached to the container body for a long period of time, there is a risk that the heat generated by the radioactive material stored in the container is transferred to the buffer body, and the strength of the buffer material constituting the buffer body is reduced. In order to prevent such a decrease in the strength of the buffer material, it is possible to suppress the heat transfer to the buffer body, but suppressing the heat transfer from the radioactive material storage container to the buffer body will hinder the heat dissipation from the radioactive material storage container, resulting in an increase in temperature of the radioactive material storage container and the stored radioactive material (such as spent nuclear fuel).

[0006] At least one embodiment of the present disclosure has been made in consideration of the above-mentioned circumstances, and aims to provide a buffer that can easily suppress a temperature rise of the buffer material used in the main body of the buffer, and a storage device for a radioactive material storage container. [Means for solving the problem]

[0007] In order to solve the above problems, at least one embodiment of the present disclosure provides a cushioning body, A buffer body attached to a radioactive material storage container that can be installed on a stand, A main body having a recess that can be engaged with an end of the radioactive material storage container; A first anisotropic heat transfer material is provided so as to cover at least a portion of the recess, and has a thermal conductivity in an in-plane direction that is higher than a thermal conductivity in an out-of-plane direction; Equipped with.

[0008] In order to solve the above problems, the storage device for a radioactive material storage container according to at least one embodiment of the present disclosure includes: A cushioning body according to at least one embodiment of the present disclosure; A stand on which the radioactive material storage container to which the buffer body is attached can be installed; Equipped with. Effect of the Invention

[0009] According to at least one embodiment of the present disclosure, it is possible to provide a buffer that can easily suppress a temperature rise in the buffer material used in the main body of the buffer, and a storage device for a radioactive material storage container. [Brief description of the drawings]

[0010] [Figure 1] FIG. 2 is a longitudinal cross-sectional view of a radioactive material storage container to which a buffer body according to at least one embodiment of the present disclosure is attached. [Diagram 2] 2 is a cross-sectional view taken along line AA in FIG. 1. [Diagram 3] 1 is a schematic diagram showing a storage device according to one embodiment from the side together with a radioactive material storage container. FIG. [Figure 4] 4 is a schematic view showing the storage device of FIG. 3 in a see-through manner from the axial direction of the radioactive material storage container. FIG. [Diagram 5] FIG. 4 is an enlarged view of the vicinity of the buffer body in FIG. 3. [Figure 6] FIG. 4 is a diagram showing another embodiment of FIG. 3. [Figure 7] FIG. 4 is a diagram showing another embodiment of FIG. 3. [Figure 8] FIG. 4 is a diagram showing another embodiment of FIG. 3. [Figure 9A] 9 is another embodiment of the heat dissipation member of FIG. 8. [Figure 9B] 9 is another embodiment of the heat dissipation member of FIG. 8. [Figure 9C] 9 is another embodiment of the heat dissipation member of FIG. 8. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, some embodiments of the present disclosure will be described with reference to the accompanying drawings. However, the dimensions, materials, shapes, relative arrangements, etc. of components described as the embodiments or shown in the drawings are merely illustrative examples and are not intended to limit the scope of the present disclosure.

[0012] FIG. 1 is a vertical cross-sectional view of a radioactive material storage container 200 to which a buffer body according to at least one embodiment of the present disclosure is attached, and FIG. 2 is a cross-sectional view taken along line AA in FIG.

[0013] The radioactive material storage container 200 has a main body shell 210 capable of storing radioactive material (e.g., spent fuel assemblies). The main body shell 210 has an opening 212 at the top and a bottomed cylindrical shape with a bottom (closed portion) 214 formed at the bottom. The main body shell 210 is formed of a forged product made of carbon steel or alloy steel having a gamma ray shielding function, but stainless steel may also be used, or a casting such as spheroidal graphite cast iron or carbon steel cast steel may also be used.

[0014] A basket 218 is disposed in a cavity 216 provided inside the main body trunk 210. As shown in Fig. 2, the basket 218 is configured by combining plate-like members in a lattice pattern to partition and form radioactive material storage sections 218A, which are multiple cells for individually storing multiple radioactive materials. In addition, a hollow spacer (not shown) capable of transferring heat is disposed in the gap generated between the inner peripheral surface of the cavity 216 and the outer periphery of the basket 218.

[0015] The opening 212 of the main body barrel 210 is closed by attaching a lid 219 to the flange surface. The lid 219 has a disk shape and is made of stainless steel or carbon steel that blocks gamma rays, and may be filled with resin (neutron shielding).

[0016] Lid 219 is detachably attached to the upper end of main body barrel 210 by, for example, stainless steel or carbon steel bolts (not shown). In this case, metal gaskets (not shown) are interposed between lid 219 and main body barrel 210 to ensure internal sealing.

[0017] An outer cylinder 220 is disposed on the outer periphery of the main body barrel 210 with a predetermined gap therebetween. A plurality of copper heat transfer fins 222 for heat transfer are provided at predetermined intervals between the outer periphery of the main body barrel 210 and the inner periphery of the outer cylinder 220, as shown in Fig. 2. Resin (neutron shielding body) 224, which is a polymer material containing a large amount of hydrogen and contains boron or a boron compound having a neutron shielding function, is injected in a fluid state through a hose (not shown) or the like into the space partitioned by the main body barrel 210, the outer cylinder 220, and the heat transfer fins 222, and is then solidified.

[0018] The main body barrel 210 is also provided with trunnions 230 formed to protrude outward. The trunnions 230 are fixed to the outer periphery of the main body barrel 210 and are provided to protrude through the outer cylinder 220 to the outside. The tip of each trunnion 230 has a shape that allows it to engage with a transport device such as a crane used during transport. Such trunnions 230 are provided at two locations on the cover 219 side protruding in opposite directions, and at two locations on the bottom 214 side protruding in opposite directions. Furthermore, the trunnions 230 may be provided at four locations on the lid portion 219 side along the circumferential direction at approximately 90 degree intervals, and may also be provided at four locations on the bottom portion 214 side along the circumferential direction at approximately 90 degree intervals.

[0019] Next, a description will be given of a storage device 100 for storing the radioactive material storage container 200 having the above-mentioned configuration. Fig. 3 is a schematic diagram showing the storage device 100 according to one embodiment from the side together with the radioactive material storage container 200, and Fig. 4 is a schematic diagram showing the storage device 100 of Fig. 3 transparently from the axial direction of the radioactive material storage container 200.

[0020] The storage device 100 is configured to be capable of storing the radioactive material storage container 200 in a state in which the container is installed on a stand. During storage, the stand 111 is placed on a substantially horizontal mounting surface 10 of a storage facility (not shown). The stand 111 is formed, for example, from a metal material, and may be fixed to the mounting surface 10. The stand 111 has a pair of first support parts 110 and a pair of second support parts 120 each standing upright from the mounting surface 10 facing upward.

[0021] The pair of first support parts 110 are provided at positions corresponding to the trunnions 230 on the bottom 214 side of the radioactive material storage container 200 mounted on the stand 111, and the pair of second support parts 120 are provided at positions capable of supporting the radioactive material storage container 200 mounted on the stand 111. Note that, while Fig. 3 illustrates an example in which the pair of second support parts 120 are provided at positions corresponding to the two trunnions 230 on the lid 219 side of the radioactive material storage container 200, the configuration is not limited as long as they are capable of contacting and supporting the outer cylinder 220 of the radioactive material storage container 200.

[0022] The state in which the radioactive material storage container 200 shown in FIG. 3 is installed is realized, for example, by transporting the radioactive material storage container 200 in a suspended state with the bottom 214 facing downward and the lid 219 facing up and down by a transport device such as a crane (not shown), and first engaging the trunnion 230 on the bottom 214 side with a pair of first support parts 110, and then rotating the radioactive material storage container 200 around the pair of first support parts 110 while supporting the trunnion 230 on the bottom 214 side, so that the lid 219 side is supported by the second support parts 120.

[0023] The radioactive material storage container 200 installed on the stand 111 in the storage device 100 as described above is fitted with buffer bodies 1A and 1B according to at least one embodiment of the present disclosure. In this embodiment, 1A attached to the end of the radioactive material storage container 200 on the bottom 214 side and 1B attached to the end of the radioactive material storage container 200 on the lid 219 side are shown, but hereinafter, when both are referred to collectively, they will be simply referred to as "buffer body 1." In the following description, unless otherwise specified, buffer body 1A and buffer body 1B have the same configuration.

[0024] Fig. 5 is an enlarged view of the vicinity of the buffer 1 in Fig. 3. The buffer 1 is configured to be attached to an end of the radioactive material storage container 200 to cushion external shocks when the radioactive material storage container 200 is transported and then installed on the stand 111 for storage. To achieve this function, the buffer 1 has a main body 4 including a buffer material 2. The buffer material 2 is configured to include a material having buffer properties, such as wood, resin, or fiber reinforced plastic (FRP).

[0025] The main body 4 has a configuration in which the above-mentioned buffer material 2 is surrounded by an outer shell 6. The outer shell 6 is made of a plate-like member including a metal material such as stainless steel, carbon steel, or aluminum alloy, and reinforces the buffer body 1 by surrounding the buffer material 2.

[0026] The main body 4 having such a configuration has a recess 8 corresponding to the end of the radioactive material storage container 200, and thus can engage with the end of the radioactive material storage container 200. If the main body 4 were to directly contact the radioactive material storage container 200 at the recess 8, heat generated by the radioactive material stored in the radioactive material storage container 200 would be transferred to the main body 4, and the strength of the buffer material 2 constituting the buffer 1 would be reduced.

[0027] In order to solve such problems, the buffer 1 has a first anisotropic heat transfer material 12 provided so as to cover at least a part of the recess 8. The first anisotropic heat transfer material 12 is configured so that the thermal conductivity σ1 in the in-plane direction is larger than the thermal conductivity σ2 in the out-of-plane direction. Such a first anisotropic heat transfer material 12 is configured, for example, from a material such as a graphene sheet. The thermal conductivity σ1 in the in-plane direction of the graphene sheet is 700 to 1950 [W / m·K], which is higher than the thermal conductivity 16.7 [W / m·K] of SUS304, which is an example of a material used for the outer shell 6 (the thermal conductivity σ2 in the out-of-plane direction of the graphene sheet is approximately the same as that of SUS304).

[0028] In this embodiment, the first anisotropic heat transfer material 12 is provided along the surface of the recess 8 so as to cover the entire recess 8 and reach the outside of the recess 8. In the recess 8, the first anisotropic heat transfer material 12 comes into contact with the end of the radioactive material storage container 200, so that heat from the radioactive material storage container 200 is transferred to the outside of the recess 8 along the in-plane direction by the first anisotropic heat transfer material 12 and dissipated. This makes it possible to suppress heat transfer from the radioactive material storage container 200 to the buffer material 2 of the buffer body 1 and effectively prevent the strength of the buffer material 2 from being reduced due to heat.

[0029] The first anisotropic heat transfer material 12 extends from the recess 8 to the heat dissipation section 14 which does not face the end of the radioactive material storage container 200 that engages with the recess 8 of the main body 4. The heat dissipation section 14 is not in contact with the main body 4 and is therefore open to the outside air. Therefore, the heat transferred from the recess 8 along the in-plane direction of the first anisotropic heat transfer material 12 is efficiently cooled by heat exchange with the outside air in the heat dissipation section 14. In this embodiment, the heat dissipation section 14 is provided so as to reach the peripheral portion of the main body 4, thereby achieving efficient cooling.

[0030] Moreover, the thermal conductivity σ1 of the first anisotropic heat transfer material 12 in an in-plane direction is greater than the thermal conductivity of the outer shell 6. As a result, in the recess 8, the amount of heat transferred in the in-plane direction of the first anisotropic heat transfer material 12 is greater than the amount of heat transferred to the buffer material 2 via the outer shell 6, so that the temperature rise of the buffer material 2 can be effectively suppressed.

[0031] 3 and the like illustrates an example in which the radioactive material storage container 200 is stored in a horizontally placed state, but the radioactive material storage container 200 may be stored in a vertically placed state. In this case, the buffer 1 may be attached only to the upper side (e.g., the lid 219 side) of the radioactive material storage container 200 in the vertically placed state, and the configurations according to the embodiments of the present application are also applicable to such a buffer 1.

[0032] Moreover, the first anisotropic heat transfer material 12 is configured to be in surface contact with the outer shell 6 in the heat dissipation section 14. That is, in the heat dissipation section 14, the first anisotropic heat transfer material 12 is provided so as to cover the outer shell 6, so that the first anisotropic heat transfer material 12 and the outer shell 6 overlap. As a result, the amount of heat transferred by the first anisotropic heat transfer material 12 is cooled by the outside air in the heat dissipation section 14 and is also dissipated to the outer shell 6, thereby obtaining a good cooling effect.

[0033] FIG. 6 is a diagram showing another embodiment of FIG. 3. The buffer body 1 according to the embodiment of FIG. 6 further includes a second anisotropic heat transfer material 16. The second anisotropic heat transfer material 16 is provided so as to at least partially cover the outer surface of the radioactive material storage container 200 mounted on the stand 111. The second anisotropic heat transfer material 16 is configured so that the thermal conductivity σ2 in the out-of-plane direction is greater than the thermal conductivity σ1 in the in-plane direction. This increases the amount of heat transferred from the radioactive material storage container 200 to the outside air by the second anisotropic heat transfer material 16 in contact with the outer surface of the radioactive material storage container 200, and promotes heat dissipation to the outside air. As a result, the amount of heat transferred from the radioactive material storage container 200 to the buffer body 1 is reduced, and the strength reduction of the buffer material 2 can be more effectively prevented.

[0034] 6, the second anisotropic heat transfer material 16 is configured to cover the entire outer surface of the radioactive material storage container 200. This increases the amount of heat transferred from the radioactive material storage container to the outside air, and further promotes heat dissipation to the outside air.

[0035] 7, the second anisotropic heat transfer material 16 may be configured to partially cover the outer surface of the radioactive material storage container 200. In FIG. 7, the second anisotropic heat transfer material 16 is partially provided on the outer surface of the radioactive material storage container 200 near the end where the buffer body 1 is attached. In this embodiment, the amount of heat dissipation in the center is reduced compared to the case where the second anisotropic heat transfer material 16 is provided on the entire outer surface of the radioactive material storage container 200 as in FIG. 6, but it is advantageous in terms of cost because it is possible to reduce the amount of heat transfer to the buffer body 1 while keeping the application range of the second anisotropic heat transfer material 16 small.

[0036] In addition, Figure 7 illustrates an example in which the area in which the second anisotropic heat transfer material 16 is provided is set to include the first support portion 110 and the second support portion 120 supported by the stand 111 on the outer surface of the radioactive substance storage container 200, but the area can be set as appropriate.

[0037] By providing such a second anisotropic heat transfer material 16 in advance on the outer surface of the radioactive material storage container 200 to be stored, the number of work steps can be reduced when installing the buffer body 1 to the radioactive material storage container 200.

[0038] FIG. 8 is a diagram showing another embodiment of FIG. 3. The storage device 100 according to the embodiment of FIG. 8 further includes a heat dissipation member 20 provided between the stand 111 and the radioactive material storage container 200 installed on the stand 111. The heat dissipation member 20 is configured to include, for example, foam metal such as aluminum. Foam metal has many pores inside, and can secure a large contact area with the outside air. In this embodiment, such a heat dissipation member 20 is interposed between the stand 111 and the radioactive material storage container 200, and thereby the amount of heat from the radioactive material storage container 200 is released from the heat dissipation member 20 to the surrounding atmosphere (atmosphere), thereby contributing to cooling of the radioactive material storage container 200. This reduces the temperature of the radioactive material storage container 200, and effectively suppresses the amount of heat transfer from the radioactive material storage container 200 to the buffer body 1. As a result, the amount of heat transfer from the radioactive material storage container 200 to the buffer body 1 can be further suppressed, and the strength reduction of the buffer material 2 can be more effectively prevented.

[0039] In addition, the surface 21 of the heat dissipation member 20 that contacts the radioactive material storage container 200 is configured to be a curved surface so as to correspond to the outer shape of the radioactive material storage container 200. This can increase the contact area between the radioactive material storage container 200 and the heat dissipation member 20, and can provide good stability of the radioactive material storage container 200 during transportation and storage.

[0040] Furthermore, by surrounding the end of the heat dissipation member 20 with a structure that allows outside air to pass through, such as a grating, the heat dissipation member 20 can be well protected even if it extends beyond the stand 111, and the above-mentioned effect can be obtained.

[0041] 8 illustrates an example in which the heat dissipation member 20 is made of foamed metal, but the heat dissipation member 20 may take other forms. For example, FIG. 9A illustrates an embodiment in which the heat dissipation member 20 is made of a plurality of metal pipes 20a extending in one direction, and a filling layer 20b made of foamed metal is formed in the space between the plurality of metal pipes 20a. The extension direction of the metal pipes 20a is, for example, approximately parallel to the ground (or floor surface) on which the stand 111 is installed. The metal pipes 20a are hollow piping members, and by allowing outside air to pass through the inside, heat exchange between the heat dissipation member 20 and the outside air is promoted, and a good cooling effect is obtained.

[0042] 9B shows a heat dissipation member 20 made of a metal having a mesh structure. In this embodiment, too, heat exchange between the heat dissipation member 20 and the outside air is promoted by allowing the outside air to pass through the hollows in the mesh structure, and a good cooling effect is obtained. Note that the heat dissipation member 20 may have a honeycomb structure instead of such a mesh structure. The heat dissipation member 20 may also be made of a lattice material formed by, for example, a 3D printer.

[0043] As shown in FIG. 9C, the storage device 100 may include a heat dissipation member 30 that covers the radioactive material storage container 200 horizontally placed on the stand 111 so as to surround it from above and below. With this arrangement, the heat dissipation member 30 can promote heat dissipation from the radioactive material storage container 200. The heat dissipation member 30 shown in FIG. 9C is configured by fixing a first member 30a that covers the radioactive material storage container 200 from above and a second member 30b that covers the radioactive material storage container 200 from below with a fixing member 30c such as a bolt or a stake. The first member 30a and the second member 30b can take various forms similar to the above-mentioned heat dissipation member 20. By surrounding the radioactive material storage container 200 with such a heat dissipation member 30, the storage device 100 can promote heat dissipation from the radioactive material storage container 200 and effectively suppress heat transfer to the buffer body 1.

[0044] Such a heat dissipation member 30 may be provided over the entire axial direction of the radioactive material storage container 200 supported on the stand 111. In this case, the amount of heat transfer from the radioactive material storage container 200 to the outside air is increased, and heat dissipation to the outside air can be further promoted.

[0045] The heat dissipation member 30 may be provided partially on the radioactive material storage container 200 supported on the stand 111. In this case, the heat dissipation member 30 may be provided only in a partial range along the axial direction of the radioactive material storage container 200 (i.e., near the end where the buffer body 1 is attached) in accordance with the second anisotropic heat transfer material 16 shown in Fig. 7, for example. In this embodiment, the amount of heat dissipation in the central portion is reduced compared to the case where the heat dissipation member 30 is provided over the entire axial direction of the radioactive material storage container 200, but the amount of heat transfer to the buffer body 1 can be reduced while keeping the application range of the heat dissipation member 30 small, which is advantageous in terms of cost.

[0046] As described above, according to each of the above-mentioned embodiments, the first anisotropic heat transfer material 12 is provided so as to cover at least a part of the recess 8. In the recess 8, the first anisotropic heat transfer material 12 comes into contact with the end of the radioactive material storage container 200, so that heat from the radioactive material storage container 200 is transferred to the outside of the recess 8 along the in-plane direction by the first anisotropic heat transfer material 12 and dissipated. This makes it possible to suppress heat transfer from the radioactive material storage container 200 to the buffer body 1 and effectively prevent a decrease in strength of the buffer material 2 due to heat.

[0047] In addition, within the scope of the present disclosure, the components in the above-described embodiments may be replaced with well-known components as appropriate, and the above-described embodiments may be combined as appropriate.

[0048] The contents described in each of the above embodiments can be understood, for example, as follows.

[0049] (1) A buffer according to one embodiment of the present invention comprises: A buffer body (e.g., the buffer body 1 in the above embodiment) that is attached to a radioactive material storage container (e.g., the radioactive material storage container 200 in the above embodiment) that can be installed on a stand (e.g., the stand 111 in the above embodiment), A main body (e.g., the main body 4 in the above embodiment) having a recess (e.g., the recess 8 in the above embodiment) that can be engaged with an end of the radioactive material storage container; A first anisotropic heat transfer material (e.g., the first anisotropic heat transfer material 12 in the above embodiment) is provided so as to cover at least a part of the recess, and has a thermal conductivity in an in-plane direction (e.g., the thermal conductivity σ1 in the above embodiment) that is greater than a thermal conductivity in an out-of-plane direction (e.g., the thermal conductivity σ2 in the above embodiment); Equipped with.

[0050] According to the above aspect (1), the first anisotropic heat transfer material is provided so as to cover at least a part of the recess. In the recess, the first anisotropic heat transfer material comes into contact with the end of the radioactive material storage container, so that heat from the radioactive material storage container is transferred to the outside of the recess along the in-plane direction by the first anisotropic heat transfer material and dissipated. This makes it possible to suppress heat transfer from the radioactive material storage container to the buffer body and effectively prevent the strength of the buffer material from being reduced due to heat.

[0051] (2) In another embodiment, in the above embodiment (1), The first anisotropic heat transfer material extends from the recess to a heat dissipation portion (for example, heat dissipation portion 14 in the above embodiment) of the main body that does not face the end of the radioactive substance storage container and engages with the recess.

[0052] According to the above aspect (2), the first anisotropic heat transfer material extends from the recess to the heat dissipation portion that is not in contact with the main body, so that the heat transferred from the recess along the in-plane direction of the first anisotropic heat transfer material is effectively cooled by heat exchange with the outside air in the heat dissipation portion.

[0053] (3) In another embodiment, in the above embodiment (1) or (2), The body has a cushioning material (e.g., the cushioning material 2 in the above embodiment) surrounded by an outer shell (e.g., the outer shell 6 in the above embodiment), The first anisotropic heat transfer material has a thermal conductivity in an in-plane direction (for example, the thermal conductivity σ1 in the above embodiment) that is greater than the thermal conductivity of the outer shell (for example, the thermal conductivity σ3 in the above embodiment).

[0054] According to the above aspect (3), the amount of heat transferred in the in-plane direction of the first anisotropic heat transfer material in the recess is greater than the amount of heat transferred to the buffer material via the outer shell, thereby effectively suppressing the temperature rise of the buffer material.

[0055] (4) In another embodiment, in the above embodiment (3), The first anisotropic heat transfer material is configured to be in surface contact with the outer shell at the heat dissipation portion.

[0056] According to the above aspect (4), the heat dissipation section is configured such that the first anisotropic heat transfer material is provided so as to cover the outer shell, and the first anisotropic heat transfer material and the outer shell overlap. This allows the amount of heat transferred by the first anisotropic heat transfer material to be cooled by the outside air in the heat dissipation section and also dissipated to the outer shell, thereby obtaining a good cooling effect.

[0057] (5) A storage device for a radioactive material storage container according to one embodiment includes: A buffer body according to any one of the above aspects (1) to (4) (for example, the buffer body 1 of the above embodiment), A stand (for example, the stand 111 in the above embodiment) on which the radioactive material storage container to which the buffer body is attached can be installed; Equipped with.

[0058] According to the above aspect (5), it is possible to easily suppress the temperature rise of the buffer material used in the main body of the buffer body attached to the radioactive material storage container, while enabling long-term storage.

[0059] (6) In another embodiment, in the above embodiment (5), The radioactive material storage container is provided with a second anisotropic heat transfer material (e.g., the second anisotropic heat transfer material 16 in the above embodiment) that has a higher thermal conductivity in the out-of-plane direction than in the in-plane direction and at least partially covers the outer surface of the radioactive material storage container mounted on the stand.

[0060] According to the above aspect (6), the second anisotropic heat transfer material, whose thermal conductivity in the out-of-plane direction is greater than its thermal conductivity in the in-plane direction, is provided so as to at least partially cover the outer surface of the radioactive material storage container mounted on the stand. This increases the amount of heat transferred from the radioactive material storage container to the outside air by the second anisotropic heat transfer material in contact with the outer surface of the radioactive material storage container, and promotes heat dissipation to the outside air. As a result, the amount of heat transferred from the radioactive material storage container to the buffer body is reduced, and the strength reduction of the buffer material can be more effectively prevented.

[0061] (7) In another embodiment, in the above embodiment (6), The second anisotropic heat transfer material covers the entire outer surface of the radioactive material storage container.

[0062] According to the above aspect (7), the amount of heat transferred from the radioactive material storage container to the outside air can be increased, and heat dissipation to the outside air can be further promoted.

[0063] (8) In another embodiment, in the above embodiment (6), The second anisotropic heat transfer material is partially provided in a region of the outer surface of the radioactive material storage container that includes the end portion to which the buffer is attached.

[0064] According to the above aspect (8), compared to the case where the second anisotropic heat transfer material is provided over the entire outer surface of the radioactive material storage container as in the above aspect (7), although the amount of heat dissipation in the central part of the radioactive material storage container is reduced, it is possible to achieve a reduction in the amount of heat transfer to the buffer body while keeping the application area of ​​the second anisotropic heat transfer material small, which is advantageous in terms of cost.

[0065] (9) In another embodiment, in at least one of (5) to (8) above, The radioactive substance storage container further includes a heat dissipation member (for example, the heat dissipation member 20 in the above embodiment) provided between the radioactive substance storage container and the stand.

[0066] According to the above aspect (9), the heat dissipation member is interposed between the stand and the radioactive material storage container, and the amount of heat from the radioactive material storage container is released from the heat dissipation member to the surrounding atmosphere (e.g., air), thereby contributing to cooling of the radioactive material storage container. This can further suppress the amount of heat transferred from the radioactive material storage container to the buffer body, and more effectively prevent the strength of the buffer material from decreasing.

[0067] (10) In another embodiment, in the above embodiment (9), The heat dissipation member includes a metal foam.

[0068] According to the above aspect (10), the heat dissipation member is configured to include a metal foam. The metal foam has many pores therein and ensures a large contact area with the outside air, thereby accelerating heat dissipation from the heat dissipation member to the surrounding atmosphere (e.g., air) and effectively cooling the heat transferred from the radioactive material storage container. [Explanation of symbols]

[0069] 1,1A,1B buffer 2 Cushioning material 4. Main unit 6. Outer shell 8 Recess 10 Placement surface 12 First anisotropic heat transfer material 14 Heat dissipation part 16 Second anisotropic heat transfer material 20,30 Heat dissipation material 20a Metal Pipe 20b Filled bed 21 sides 30a First member 30b Second member 30c Fixing member 100 Storage Device 110 1st support part 111 Mount 120 Second support part 200 Radioactive material storage container 210 Main body 212 Opening 214 Bottom 216 Cavity 218 Basket 218A Radioactive material storage section 219 Lid 220 Outer Cylinder 222 Heat transfer fin 230 Trunnion

Claims

1. A buffer body attached to a radioactive material storage container that can be installed on a stand, A main body having a recess that can be engaged with an end of the radioactive material storage container; A first anisotropic heat transfer material is provided so as to cover at least a portion of the recess, and has a thermal conductivity in an in-plane direction that is higher than a thermal conductivity in an out-of-plane direction; A buffer body comprising:

2. The buffer body according to claim 1 , wherein the first anisotropic heat transfer material extends from the recess to a heat dissipation portion of the main body that does not face the end of the radioactive material storage container that engages with the recess.

3. The body has a cushioning material surrounded by an outer shell; The buffer body according to claim 1 , wherein the first anisotropic heat transfer material has a thermal conductivity in an in-plane direction that is greater than a thermal conductivity of the outer shell.

4. The buffer body according to claim 2 , wherein the first anisotropic heat transfer material is configured to be in surface contact with the outer shell in the heat dissipation portion.

5. A shock absorber according to any one of claims 1 to 4, A stand on which the radioactive material storage container to which the buffer body is attached can be installed; and A storage device for a radioactive material container comprising:

6. 6. The storage device for a radioactive material storage container as described in claim 5, further comprising a second anisotropic heat transfer material having a higher thermal conductivity in an out-of-plane direction than in an in-plane direction and at least partially covering an outer surface of the radioactive material storage container mounted on the stand.

7. The storage device for a radioactive material storage container according to claim 6 , wherein the second anisotropic heat transfer material covers an entire outer surface of the radioactive material storage container.

8. The storage device for a radioactive material storage container according to claim 6 , wherein the second anisotropic heat transfer material is partially provided in an area of ​​an outer surface of the radioactive material storage container that includes the end to which the buffer is attached.

9. The storage device for a radioactive material storage container according to claim 5 , further comprising a heat dissipation member provided between the radioactive material storage container and the stand.

10. The storage device for a radioactive material storage container according to claim 9 , wherein the heat dissipation member includes a foam metal.

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