JP5848651B2 - Nuclear fuel storage container and method of storing fuel assembly in nuclear fuel storage container - Google Patents

Description

  The present invention relates to a nuclear fuel storage container and a method for storing a fuel assembly in a nuclear fuel storage container, and in particular, a nuclear fuel storage container and a fuel assembly suitable for transporting and storing spent fuel assemblies taken out from a nuclear reactor. The present invention relates to a method for storing a body in a nuclear fuel storage container.

  A fuel assembly loaded in a reactor core in a nuclear reactor pressure vessel and used after a predetermined period of time is stored in a cooling pool in a nuclear power plant and cooled. Spent fuel assemblies that have been stored for a predetermined period and have a reduced decay heat generation amount are stored in nuclear fuel storage containers, transported to an intermediate storage facility, and stored in the intermediate storage facility. In order to prevent radiation leakage from the spent fuel assembly inside during transportation and storage, the nuclear fuel storage container is provided with radiation shielding.

  A nuclear fuel storage container usually has a cylindrical container body having an open upper end, a basket having a lattice-like cross section installed in the container body, and a plurality of lid members that seal the opening of the container body. A plurality of spent fuel assemblies in which a plurality of fuel rods are bundled are stored in respective regions partitioned by a basket in the container body.

  Even in the case of dropping from a high place or the like during transportation, such nuclear fuel storage container is required not to leak the nuclear fuel material contained in the spent fuel assembly stored inside. In response to such a requirement, usually, a wooden cushion is attached to each of the upper end and the lower end of the container body. In order to further improve the safety of the spent fuel assembly inside when the nuclear fuel storage container is subjected to an impact, it is also considered to install an impact absorbing device in the container body. In consideration of reducing the load applied to the lid member at the time of dropping, it is effective to dispose an impact absorbing device between the stored spent fuel assembly and the lid member.

  JP-A-2011-1305 and JP-A-2002-341085 describe that an impact absorbing device is disposed between a spent fuel assembly and a lid member.

  Japanese Patent Application Laid-Open No. 2011-1305 describes an impact absorbing device in which a cover member is provided with a plurality of cylindrical buffer bodies. A plurality of spent fuel assemblies into which a combustible poison assembly is inserted from above are stored in a fuel assembly storage container (nuclear fuel storage container), and an impact absorbing device includes a cover member of the fuel assembly storage container and the fuel assembly It arrange | positions between the spent fuel assemblies in a storage container.

  Japanese Patent Laid-Open No. 2002-341085 describes a concrete cask (nuclear fuel storage container) in which a canister for storing a spent fuel assembly is installed. A grid-like basket defining a storage area for spent fuel assemblies is provided in the container body of the canister, and a shielding plate is placed above the basket. A plurality of spacers, which are shock absorbers, are attached to the lower surface of the shielding plate, and each spacer is disposed above each spent fuel assembly housed in the container body of the canister (Japanese Patent Laid-Open No. 2002-341085). See FIG. 17 of the publication). Each spacer has a cylindrical shape (cylindrical shape, rectangular tube shape) or a rod shape (columnar shape, prismatic shape). Furthermore, FIG. 18 of Japanese Patent Laid-Open No. 2002-341085 describes that a holding plate to which those spacers are attached is arranged in a container body of a canister and supported by a basket. Each spacer provided on the holding plate is disposed between the spent fuel assembly housed in the container body and the shielding plate.

JP 2011-13035 A Japanese Patent Laid-Open No. 2002-341085

  When a nuclear fuel storage container falls from a high place, the impact absorbing device as described above arranged in each fuel storage container has an impact applied between the spent fuel assembly stored in the nuclear fuel storage container and the lid member. Energy is absorbed by receiving a load and deforming due to buckling or plasticity, and the load acting on the spent combustion assembly and the cover member of the nuclear fuel storage container is reduced. However, since the shape of the shock absorbing device that has absorbed the impact changes greatly, each of the nuclear fuel storage containers described in Japanese Patent Laid-Open Nos. 2011-13035 and 2002-341085 uses a deformed shock absorbing device. May interfere with spent fuel assemblies and nuclear fuel storage baskets. For this reason, there is a possibility that the greatly deformed shock absorbing device is caught by the basket or the spent fuel assembly in the nuclear fuel storage container and it becomes difficult to take out the spent fuel assembly from the nuclear fuel storage container.

  An object of the present invention is to provide a nuclear fuel storage container that can prevent damage to an internal fuel assembly at the time of dropping and that can be easily taken out, and a method for storing the fuel assembly in the nuclear fuel storage container. There is to do.

  A feature of the present invention that achieves the above-described object is that a container body having a lower end sealed and an upper end opened, a basket that is installed in the container body and defines a plurality of storage areas for the fuel assembly, and a container A lid member that is detachably attached to the upper end of the main body, and an impact absorbing device that is disposed between the fuel assembly and the lid member in a state in which the fuel assembly is stored in each storage region, The absorber includes a connecting portion and a plurality of shock absorbing portions connected to the connecting portion, and each shock absorbing portion is connected to the plate-like side wall portion connected to the connecting portion and the side wall portion. It exists in including the bending part which opposes a fuel assembly.

  When the nuclear fuel storage container falls, the impact force applied to the lid member by the internal fuel assembly can be absorbed by the deformation of the shock absorbing portion of the shock absorber, and the fuel assembly is damaged when the nuclear fuel storage container falls. Can be prevented. Further, when the nuclear fuel storage container is dropped, the shock absorbing portion is deformed in the thickness direction of the side wall portion rather than the width direction of the side wall portion of the shock absorbing portion, so that the deformed shock absorbing portion, the basket and the nuclear fuel storage container Interference with the structural member of the fuel assembly can be avoided. Therefore, the fuel assembly can be easily taken out from the dropped nuclear fuel storage container.

  According to the present invention, it is possible to prevent damage to the fuel assembly existing inside the nuclear fuel storage container when the nuclear fuel storage container is dropped, and to easily remove the internal fuel assembly from the nuclear fuel storage container after the nuclear fuel storage container is dropped. Can be taken out.

It is a perspective view of the nuclear fuel storage container of Example 1 which is one suitable Example of this invention. It is a perspective view which shows the internal structure of the nuclear fuel storage container shown in FIG. It is a perspective view of the spent fuel assembly accommodated in the nuclear fuel storage container shown in FIG. It is a perspective view of the impact-absorbing device provided in the nuclear fuel storage container shown in FIG. It is a block diagram inside the nuclear fuel storage container shown in FIG. 1 which provided the impact-absorbing device shown in FIG. It is the top view which looked at arrangement | positioning of the impact-absorbing device in FIG. 5 from upper direction. It is explanatory drawing which shows the state which deform | transformed when the impact-absorbing device shown in FIG. 4 received the impact. It is a block diagram inside the nuclear fuel storage container of Example 2 which is another Example of this invention. It is the top view which looked at the arrangement | positioning of an impact-absorbing device in FIG. 8 from upper direction. It is a perspective view of the shock absorber shown in FIG. It is a perspective view of the impact-absorbing device provided in the nuclear fuel storage container of Example 3 which is another Example of this invention. It is a perspective view of the impact-absorbing device provided in the nuclear fuel storage container of Example 4 which is another Example of this invention. It is explanatory drawing which shows the state which deform | transformed when the impact-absorbing device shown in FIG. 12 received the impact. It is a perspective view of the impact-absorbing device provided in the nuclear fuel storage container of Example 5 which is another Example of this invention. It is a perspective view of the impact-absorbing device provided in the nuclear fuel storage container of Example 6 which is another Example of this invention. It is a perspective view of the impact-absorbing device provided in the nuclear fuel storage container of Example 7 which is another Example of this invention.

  Examples of the present invention will be described below.

  A nuclear fuel storage container according to embodiment 1 which is a preferred embodiment of the present invention will be described with reference to FIGS. The nuclear fuel storage container 1 of this embodiment stores a spent fuel assembly taken out from the core of a boiling water reactor. The nuclear fuel storage container 1 of the present embodiment can also be applied to a nuclear fuel storage container that stores spent fuel assemblies generated in other nuclear reactors such as a pressurized water reactor.

  The nuclear fuel storage container 1 includes a container body 2, a basket 3, lid members 4A, 4B, and 4C, and an impact absorbing device 5. A lattice-like basket 3 is installed in the container main body 2 and demarcates a storage area of each of the plurality of spent fuel assemblies 9 stored in the container main body 2. The lid members 4A, 4B, 4C are arranged in the order of the lid members 4A, 4B, 4C from the upper end of the basket 3 to the upper side, and are detachably attached to the container body 2. The lid members 4A, 4B, and 4C are attached to the container body 2 after a predetermined number of spent fuel assemblies 9 are stored in the container body 2.

  A spent fuel assembly 9 taken out from the core of the boiling water reactor includes a plurality of fuel rods 10, a lower tie plate (lower fuel support member) 11, an upper tie plate (upper fuel support member) 12, and a channel box 15. Have The lower end portion of each fuel rod 10 is supported by a lower tie plate 11, and the upper end portion of each fuel rod 10 is held by an upper tie plate 12. A handle 13 is provided on the upper tie plate 12. These fuel rods 10 are bundled by a fuel spacer 14 so as to form a predetermined interval between them. The bundle of fuel rods 10 bundled by the fuel spacer 14 is surrounded by a channel box 15 attached to the upper tie plate 12. The channel box 15 extends from the upper tie plate 12 toward the lower tie plate 11.

  The spent fuel assembly 9 taken out from the core of the boiling water reactor is stored in a fuel storage pool in a nuclear power plant and cooled by cooling water. A plurality of spent fuel assemblies 9 that have been stored in the fuel storage pool for a predetermined period and the amount of decay heat generated has decreased, are stored in the storage areas defined by the basket 3 in the container body 2 of the nuclear fuel storage container 1. Stored inside. After the predetermined number of spent fuel assemblies 9 are stored, the impact absorbing device 5 is placed on the spent fuel assemblies 9, and the lid members 4A, 4B, 4C are arranged in this order in the container body. 2 and the container body 2 is sealed.

  As shown in FIG. 4, the shock absorbing device 5 used in this embodiment includes a pair of connecting portions 6 </ b> A and 6 </ b> B and a plurality of U-shaped shock absorbing portions 7. The impact absorbing portion 7 has, for example, a plate shape with a width of 30 mm and a thickness of 5 mm. One end of each impact absorbing portion 7 is connected to the connecting portion 6A, and the other end of each impact absorbing portion 7 is connected to the connecting portion 6B. Each shock absorbing portion 7 is formed with a curved portion 16 having a curved surface. In the shock absorbing part 7, the part between the connecting part 6A and the bent part 16 and the part between the connecting part 6B and the bent part 16 are side wall parts. The width direction of the side wall portion of the shock absorbing portion 7 is the longitudinal direction of the connecting portion 6A (or connecting portion 6B).

  The shock absorber 5 is manufactured as follows. By pressing one plate, the plate-like impact absorbing portion 7, the plate-like connecting portion 6 </ b> A connected to one end of the impact absorbing portion 7, and the plate-like connecting portion connected to the other end of the impact absorbing portion 7 are used. An intermediate product having a connecting portion 6B is obtained, and the shock absorbing device 5 is manufactured by bending each impact absorbing portion 7 of this intermediate product into a U-shape by pressing so that the connecting portions 6A and 6B face each other. be able to.

  After the plurality of spent fuel assemblies 9 are separately stored in the storage areas defined by the basket 3 in the container main body 2 and before the cover members 4A, 4B, 4C are attached, the shock absorbing device 5 It is arranged for each row of spent fuel assemblies 9 housed in the inside 2. The connecting portions 6A and 6B of the shock absorbing device 9 are placed on the upper surface of the handle 13 of each spent fuel assembly 9 included in each row (see FIG. 6). At this time, each shock absorbing portion 7 of the shock absorbing device 9 is separately inserted inside the upper end portion of the channel box 15 of each spent fuel assembly 9 included in the row, and the bent portion 16 of the shock absorbing portion 7 is inserted. Faces the upper surface of the upper tie plate 12 of the spent fuel assembly 9. The lower surface of the bent portion 16 contacts the upper surface of the upper tie plate 12 (see FIG. 5). The lower surface of the bent portion 16 may not be in contact with the upper surface of the upper tie plate 12 and may be positioned slightly above the upper surface of the upper tie plate 12.

  Each impact absorbing device 9 is connected to the nuclear fuel storage container so that the lower surface of the bent portion 16 is brought into contact with the upper surface of the upper tie plate 12 to form a gap between the lower surface of each of the coupling portions 6A and 6B and the upper surface of the handle 13. 1 may be disposed between the spent fuel assembly 9 and the lid member 4A.

  The impact absorbing portion 7 is disposed between the inner surface of the channel box 15 and the handle 13 in the longitudinal direction of the connecting portions 6A and 6B. At this time, the bent portion 16 of the shock absorbing portion 7 faces the side surface of the shock absorbing portion 7 in the width direction of the shock absorbing portion 7 (positioned along the direction orthogonal to the longitudinal direction of the connecting portions 6A and 6B). It is located on one side of the channel box 15 at the center of that side of the channel box 15 located on the side of the shock absorber 7. In the integral spent fuel assembly 9, two impact absorbing portions 7 are inserted inside the channel box 15 at the upper end portion of the channel box 15. A handle 13 for the spent fuel assembly 9 exists between the two shock absorbers 7 inserted into the upper end portion of the channel box 15 of the integral spent fuel assembly 9.

  After each impact absorbing device 5 is placed on the handle 13 of the spent fuel assembly 9 in each row, the respective lid members are attached to the container body 2 in the order of the lid members 4A, 4B, 4C. When the lid member 4A is attached to the container body 2, the connecting portions 6A and 6B of the shock absorber 9 are disposed between the handle 13 and the lid member 4A. In this state, a slight gap is formed between the upper surface of each of the connecting portions 6A and 6B and the lid member 4A. The upper surfaces of the connecting portions 6A and 6B may contact the lid member 4A.

  A predetermined number of spent fuel assemblies 9 are accommodated, and as described above, a plurality of impact absorbing devices 9 are placed on the spent fuel assemblies 9 inside the container body 2 and sealed in the nuclear fuel storage container 1. Are transported from nuclear power plants to nuclear fuel reprocessing or interim storage facilities. In order to reduce the impact on the nuclear fuel storage container 1 when the nuclear fuel storage container 1 is dropped, a wood impact buffer is attached to the upper and lower parts of the nuclear fuel storage container 1 to be transported.

In this transportation, it is assumed that the nuclear fuel storage container 1 has fallen from the high place to the ground with the lid member 4C facing down. The impact force received by the nuclear fuel storage container 1 when the nuclear fuel storage container 1 falls on the ground is alleviated by the above-described impact shock absorber of wood. At the time of dropping, the impact force on the lid member 4A by the spent fuel assemblies 9 in the nuclear fuel storage container 1 is absorbed by the deformation of the respective impact absorbing portions 7 provided in the respective impact absorbing devices 5. Since the shock absorbing part 7 has a shape in which a flat plate is bent in a U shape so as to form a bent part 16, the shock absorbing part 7 is in the width direction of the shock absorbing part 7, that is, the connecting parts 6A and 6B. not deformed in the longitudinal direction, is deformed in a direction perpendicular to the longitudinal direction (direction of the arrow 8 shown in FIG. 7) (see FIG. 7).

  As described above, the shock absorbing portion 7 that has received the impact force described above is deformed in one direction, that is, in a direction orthogonal to the longitudinal direction of the connecting portions 6A and 6B. It is difficult to interfere with the structural member (basket 3) of the storage container 1 or the structural member (handle 13 and / or channel box 15) of the spent fuel assembly 9. In particular, in this embodiment, the bent portion 16 of the shock absorbing portion 7 faces the side surface of the shock absorbing portion 7 in the width direction of the shock absorbing portion 7 as described above (the longitudinal direction of the connecting portions 6A and 6B). Is located in the center of the one side of the channel box 15 located on the side of the shock absorbing portion 7, and is thus deformed. These structural members are less likely to interfere with each other. In order to avoid the interference between the deformed shock absorbing portion 7 and those structural members, the deformation of the shock absorbing portion 7 proceeds in the direction orthogonal to the longitudinal direction of the connecting portions 6A and 6B (the direction of the arrow 8). It is desirable to form a gap d (see FIG. 6) having a predetermined width between the shock absorbing portion 7 and each of the basket 3, the handle 13, and the channel box 15. The width of the gap d is set in advance so that the deformation of the shock absorbing portion 7 is predicted in advance by deformation analysis or the like, and the amount of deformation of the shock absorbing portion 7 is smaller than the gap d.

  In this embodiment, a predetermined number of spent fuel assemblies 9 are stored in an impact absorbing device 9 having a plurality of U-shaped impact absorbing portions 7 connected at both ends to the connecting members 6A and 6B. Since the fuel is disposed between the spent fuel assembly 9 and the lid member 4A attached to the container body 2 in the nuclear fuel storage container 1, the nuclear fuel storage container 1 falls from a high place and those spent fuel assemblies are disposed. 9 can absorb the impact force applied to the lid member 4A by deformation of each impact absorbing portion 7 of the impact absorbing device 9, and damage the spent fuel assembly 9 and the lid member 4A when the nuclear fuel storage container 1 is dropped. Can be prevented.

  Further, the deformation of each shock absorbing portion 7 that occurs at the time of dropping has directivity in the direction in which the deformation progresses, as described above, as compared to Japanese Patent Application Laid-Open Nos. 2011-1305 and 2002-341085. That is, since it proceeds in a direction orthogonal to the longitudinal direction of the connecting members 6A and 6B (thickness direction of the side wall portion of the shock absorbing portion 7), the deformed shock absorbing portion 7, the basket 3, the handle 13, and the channel box 15 Thus, interference with the spent fuel assembly 9 can be avoided. For this reason, the spent fuel assembly 9 in the nuclear fuel storage container 1 can be easily taken out by detaching the lid members 4C, 4B, 4A sequentially from the dropped nuclear fuel storage container 1.

  Further, since each shock absorbing device 5 is provided with a plurality of shock absorbing portions 7 in the connecting portions 6A and 6B, each shock absorbing portion 7 is arranged to face a plurality of spent fuel assemblies 9 arranged in a row. It is possible to perform the arrangement work of the plurality of shock absorbing portions 7 efficiently.

  When the spent fuel assembly 9 is disposed within the storage area defined by the basket 3, the handle 13 of the spent fuel assembly 9 may be in the direction 13A shown in FIG. The shock absorbing device 5 used in the present embodiment is arranged such that each shock absorbing portion 7 faces the spent fuel assembly 9, specifically, the upper surface of the upper tie plate 12, regardless of the direction of the handle 13. can do.

  The nuclear fuel storage container of Example 2 which is another Example of this invention is demonstrated using FIGS. 8-10. The nuclear fuel storage container 1A of the present embodiment has a configuration in which the impact absorbing device 5 is replaced with the impact absorbing device 5A in the nuclear fuel storage container 1 of the first embodiment. The other configuration of the nuclear fuel storage container 1A is the same as that of the nuclear fuel storage container 1.

  The shock absorbing device 5A includes a connecting portion 6 and a plurality of U-shaped shock absorbing portions 7A (see FIG. 10). Each shock absorbing portion 7A is connected to the connecting portion 6 at both ends. Adjacent impact storage portions 7 </ b> A are connected by a connecting portion 6. Each impact absorbing portion 7A has a curved portion 16A having a curved surface at the lower end. In the impact absorbing portion 7A, the portion between the connecting portion 6A and the bent portion 16A and the portion between the connecting portion 6B and the bent portion 16A are side wall portions. In the shock absorbing device 5A, the width direction of the side wall portion of the shock absorbing portion 7 is orthogonal to the longitudinal direction of the connecting portion 6A (or connecting portion 6B). The shock absorbing device 5A having such a configuration is manufactured by bending a single flat plate, and the width of the connecting portion 6 and the width of the shock absorbing portion 7A are the same.

  A predetermined number of spent fuel assemblies 9 are stored in order in each storage region formed in the basket 3 in the container body 2 of the nuclear fuel storage container 1A. After these storages are completed, the shock absorbing device 5A is placed on the corresponding spent fuel assemblies 9. The shock absorbing device 5 </ b> A is disposed in the container body 2 so that the connecting portion 6 is parallel to the handle 13 of the spent fuel assembly 9. The shock absorbing device 5A is arranged in the diagonal direction of the spent fuel assembly 9 in the container body 2 (see FIG. 9). The lower surface of the bent portion 16A of each shock absorbing portion 7A of the shock absorbing device 5A is in contact with the upper surface of the upper tie plate 12 of the spent fuel assembly 9 (see FIG. 8). After the plurality of shock absorbing devices 5A are placed on each spent fuel assembly 9 in the diagonal direction of the spent fuel assembly 9, the lid members 4A, 4B, 4C are sequentially removed from the container body 2 respectively. Installed as possible. In this way, the container body 2 in which the spent fuel assembly 9 is stored is sealed by the lid members 4A, 4B, 4C.

  In the nuclear fuel storage container 1A in which the spent fuel assembly 9 is housed and sealed by the lid members 4A, 4B, 4C, each impact absorbing device 5A is disposed between the spent fuel assembly 9 and the lid member 4A. ing. When the nuclear fuel storage container 1A storing the spent fuel assemblies 9 falls from a high position with the lid member facing down, the impact force of the spent fuel assemblies 9 in the nuclear fuel storage container 1A on the lid member 4A is It is absorbed by the deformation of each shock absorbing portion 7A provided in each shock absorbing device 5A. Since the plate-like impact absorbing portion 7A is U-shaped, when it is deformed by an impact force, the impact absorbing portion 7A is arranged in the width direction of the impact absorbing portion 7A (the direction orthogonal to the longitudinal direction of the connecting portion 6). ) Rather than in the diagonal direction of the spent fuel assembly 9, which is the longitudinal direction of the connecting portion 6 (the direction of the arrow 8).

  In the present embodiment, each effect produced in the first embodiment can be obtained. As described above, the direction in which the deformation of the shock absorbing portion 7A proceeds is the diagonal direction of the spent fuel assembly 9, and therefore, between the shock absorbing portion 7A and each of the basket 3, the handle 13, and the channel box 15. The width of the gap d to be formed is longer than the width of the gap d in the first embodiment. For this reason, in the nuclear fuel storage container 1A, the probability that the deformed shock absorbing portion 7A interferes with those structural members is further reduced.

  Since the shock absorbing portion 7A can be manufactured by bending a single thin plate, the amount of material required can be reduced as compared with the shock absorbing portion 7 used in the first embodiment.

  A nuclear fuel storage container according to embodiment 3, which is another embodiment of the present invention, will be described with reference to FIG. The nuclear fuel storage container 1B of the present embodiment has a configuration in which the impact absorbing device 5 is replaced with the impact absorbing device 5B in the nuclear fuel storage container 1 of the first embodiment. The other configuration of the nuclear fuel storage container 1B is the same as that of the nuclear fuel storage container 1.

  The shock absorbing device 5B has connecting portions 6A and 6B and a plurality of U-shaped shock absorbing portions 7B. Both end portions of each shock absorbing portion 7B are connected to the connecting portions 6A and 6B in the same manner as the shock absorbing device 5. The shock absorbing portion 7B has a flat bent portion 16B at the lower end, and the opposite side wall portions of the shock absorbing portion 7B (the portion between each of the connecting portions 6A and 6B and the bent portion 16B) are inside and It has a bellows shape that is folded alternately on the outside.

  Similar to the nuclear fuel storage container 1 of the first embodiment, the shock absorbing device 5B is disposed between the spent fuel assembly 9 stored in the container main body 2 and the lid member 4A attached to the container main body 2. Each shock absorbing portion 7B of the shock absorbing device 5B is inserted inside the channel box 15 at the upper end of the channel box 15 of the corresponding spent fuel assembly 9, and the bent portion 16B of the shock absorbing portion is used in the spent fuel assembly. 9 is opposed to the upper surface of the upper tie plate 12.

  In the present embodiment, each effect produced in the first embodiment can be obtained.

  When the nuclear fuel storage container 1B storing the spent fuel assemblies 9 falls from a high position with the lid member facing down, the impact force of the spent fuel assemblies 9 in the nuclear fuel storage container 1B on the lid member 4A is It is absorbed by the deformation of each shock absorbing portion 7B provided in each shock absorbing device 5B. At this time, the deformation of the shock absorbing portion 7B is mainly in the direction from the bent portion 16B toward the connecting portions 6A and 6B (the direction of the arrow 8A shown in FIG. 11). This is because the side wall portion of the shock absorbing portion 7B has a bellows shape, and the shock absorbing portion 7B is likely to be deformed in the direction of the arrow 8A. The amount of deformation in the direction orthogonal to the longitudinal direction of the connecting portions 6A and 6B is the amount of deformation in the direction of the arrow 8 of the shock absorbing portion 7 of the shock absorbing device 5 used in the first embodiment and the shock used in the second embodiment. The amount of deformation in the direction of the arrow 8 of the shock absorbing portion 7A of the absorbing device 5A is significantly reduced. For this reason, the probability of interfering with the deformed shock absorbing portion 7B in the present embodiment and each of the basket 3, the handle 13, and the channel box 15 is further reduced.

  The nuclear fuel storage container of Example 4 which is another Example of this invention is demonstrated using FIG. The nuclear fuel storage container 1C of the present embodiment has a configuration in which the impact absorbing device 5 in the nuclear fuel storage container 1 of the first embodiment is replaced with an impact absorbing device 5C. Other configurations of the nuclear fuel storage container 1 </ b> C are the same as those of the nuclear fuel storage container 1.

  Similarly to the shock absorbing device 5 used in the first embodiment, the shock absorbing device 5C is a U-shape in which the connecting portions 6A and 6B and one end are connected to the connecting portion 6A and the other end is connected to the connecting portion 6B. -Like shock absorbing portion 7C. A bent portion 16C having a curved surface is formed at the lower end of the shock absorbing portion 7C. The shock absorbing device 5C differs from the shock absorbing device 5 in that the side wall portions 17A and the side wall portions 17B facing each other of the shock absorbing portion 7C have different widths. The width of the side wall portion 17A is narrower than the width of the side wall portion 17B. In the shock absorbing portion 7C, the side wall portion 17A is a portion between the connecting portion 6A and the bent portion 16B, and the side wall portion 17B is a portion between the connecting portion 6B and the bent portion 16B.

  Similar to the nuclear fuel storage container 1 of the first embodiment, the shock absorbing device 5C is disposed between the spent fuel assembly 9 stored in the container main body 2 and the lid member 4A attached to the container main body 2. Each shock absorbing portion 7C of the shock absorbing device 5C is inserted inside the channel box 15 at the upper end of the channel box 15 of the corresponding spent fuel assembly 9, and the bent portion 16C of the shock absorbing portion is used in the spent fuel assembly. 9 is opposed to the upper surface of the upper tie plate 12.

  In the present embodiment, each effect produced in the first embodiment can be obtained.

  When the nuclear fuel storage container 1C storing the spent fuel assemblies 9 falls from a high place with the lid member facing down, the impact force of the spent fuel assemblies 9 in the nuclear fuel storage container 1C on the lid member 4A is It is absorbed by the deformation of each impact absorbing portion 7C provided in each impact absorbing device 5C. At this time, since the width of the side wall portion 17A is narrower than the width of the side wall portion 17B, the deformation of the shock absorbing portion 7C when receiving an impact load occurs earlier in the side wall portion 17A than the side wall portion 17B ( (See FIG. 13). For this reason, the shock absorbing portion 7C is further easily deformed in the direction orthogonal to the connecting portions 6A and 6B.

  The nuclear fuel storage container of Example 5 which is another Example of this invention is demonstrated using FIG. The nuclear fuel storage container 1D of the present embodiment has a configuration in which the impact absorbing device 5 is replaced with the impact absorbing device 5D in the nuclear fuel storage container 1 of the first embodiment. Other configurations of the nuclear fuel storage container 1D are the same as those of the nuclear fuel storage container 1.

  The shock absorbing device 5D includes connecting portions 6A and 6B and a plurality of U-shaped shock absorbing portions 7D. Both end portions of each shock absorbing portion 7D are connected to the connecting portions 6A and 6B in the same manner as the shock absorbing device 5. The shock absorbing portion 7D has a planar bent portion 16D formed at the lower end, similarly to the shock absorbing portion 7C. Unlike the shock absorbing portion 7C, the opposite side wall portions (portions between the connecting portions 6A and 6B and the bent portion 16D) of the shock absorbing portion 7D have a flat plate shape.

  Similar to the nuclear fuel storage container 1 of the first embodiment, the shock absorbing device 5D is disposed between the spent fuel assembly 9 stored in the container main body 2 and the lid member 4A attached to the container main body 2. Each shock absorbing portion 7D of the shock absorbing device 5D is inserted inside the channel box 15 at the upper end portion of the channel box 15 of the corresponding spent fuel assembly 9, and the bent portion 16D of the shock absorbing portion is used in the spent fuel assembly. 9 is opposed to the upper surface of the upper tie plate 12.

  When the nuclear fuel storage container 1D storing the spent fuel assemblies 9 falls from a high place with the lid member facing down, the impact force of each spent fuel assembly 9 in the nuclear fuel storage container 1D on the lid member 4A is Each shock absorbing portion 7D provided in each shock absorbing device 5D is absorbed by being deformed in a direction (direction of arrow 8) perpendicular to the longitudinal direction of the connecting portions 6A and 6B.

  In the present embodiment, each effect produced in the first embodiment can be obtained.

  The nuclear fuel storage container of Example 6 which is another Example of this invention is demonstrated using FIG. The nuclear fuel storage container 1E of the present embodiment has a configuration in which the impact absorbing device 5 is replaced with the impact absorbing device 5E in the nuclear fuel storage container 1 of the first embodiment. Other configurations of the nuclear fuel storage container 1E are the same as those of the nuclear fuel storage container 1.

  The shock absorbing device 5E has a connecting part 6 and a plurality of shock absorbing parts 7E. The end of each shock absorbing part 7E is connected to the connecting part 6. The shock absorbing portion 7E has a curved portion 16E having a curved surface at the lower end, and unlike the shock absorbing portion 7 of the shock absorbing device 5 used in the first embodiment, one side wall portion (the connecting portion 6 and the bent portion). 16E).

  Similar to the nuclear fuel storage container 1 of the first embodiment, the shock absorbing device 5E is disposed between the spent fuel assembly 9 stored in the container main body 2 and the lid member 4A attached to the container main body 2. Each shock absorbing portion 7E of the shock absorbing device 5E is inserted inside the channel box 15 at the upper end portion of the channel box 15 of the corresponding spent fuel assembly 9, and the bent portion 16E of the shock absorbing portion is used in the spent fuel assembly. 9 is opposed to the upper surface of the upper tie plate 12.

  When the nuclear fuel storage container 1E storing the spent fuel assemblies 9 falls from a high position with the lid member facing down, the impact force of each spent fuel assembly 9 in the nuclear fuel storage container 1E on the lid member 4A is Each shock absorbing portion 7E provided in each shock absorbing device 5E is absorbed by being deformed in a direction (direction of arrow 8) perpendicular to the longitudinal direction of the connecting portions 6A, 6B.

  In the present embodiment, each effect produced in the first embodiment can be obtained. Since the shock absorbing portion 7E has only one side wall portion, the shock absorbing device 5E can reduce the amount of material required for manufacturing compared to the shock absorbing device 5.

  The nuclear fuel storage container of Example 7 which is another Example of this invention is demonstrated using FIG. The nuclear fuel storage container 1F of the present embodiment has a configuration in which the impact absorbing device 5 is replaced with the impact absorbing device 5F in the nuclear fuel storage container 1 of the first embodiment. The other configuration of the nuclear fuel storage container 1F is the same as that of the nuclear fuel storage container 1.

  The shock absorbing device 5F includes connecting portions 6A and 6B and a plurality of U-shaped shock absorbing portions 7F. Both ends of each shock absorbing portion 7F are connected to the connecting portions 6A and 6B in the same manner as the shock absorbing device 5. The shock absorbing portion 7F forms a bent portion 16F having a curved surface at the lower end, similarly to the shock absorbing portion 7. Notched portions 18 extending in the longitudinal direction of the connecting portions 6A and 6B are formed in opposite side wall portions of the shock absorbing portion 7F (portions between the connecting portions 6A and 6B and the bent portion 16D), respectively. Yes. In the shock absorbing portion 7F, one notch portion 18 is formed on the side surface of the side wall portion between the connecting portion 6A and the bent portion 16D that does not face the side wall portion between the connecting portion 6B and the bent portion 16D. The other notch portion 18 is formed on the side surface of the side wall portion between the connecting portion 6B and the bent portion 16D and on the side surface facing the side wall portion between the connecting portion 6A and the bent portion 16D. For this reason, both the notch parts 18 are open | released toward the same direction. The thickness of the cutout portion 18 of the shock absorbing portion 7F is thinner than the thickness of other portions of the shock absorbing portion 7F.

  Similarly to the nuclear fuel storage container 1 of the first embodiment, the shock absorbing device 5F is disposed between the spent fuel assembly 9 stored in the container body 2 and the lid member 4A attached to the container body 2. Each shock absorbing portion 7F of the shock absorbing device 5F is inserted inside the channel box 15 at the upper end of the channel box 15 of the corresponding spent fuel assembly 9, and the bent portion 16F of the shock absorbing portion is used in the spent fuel assembly. 9 is opposed to the upper surface of the upper tie plate 12.

  When the nuclear fuel storage container 1F storing the spent fuel assemblies 9 falls from a high position with the lid member facing down, the impact force of each spent fuel assembly 9 in the nuclear fuel storage container 1F on the lid member 4A is Each shock absorbing portion 7F provided in each shock absorbing device 5F is absorbed by being deformed in the direction of the arrow 8 which is a direction orthogonal to the longitudinal direction of the connecting portions 6A and 6B.

  In the present embodiment, each effect produced in the first embodiment can be obtained.

  In Example 1 and Examples 3 to 7, when the nuclear fuel storage container in which the spent fuel assembly 9 is stored falls with the lid member facing downward, the impact force that the lid member 4A receives by the spent fuel assembly 9 Thus, the shock absorbing portion of each shock absorbing device is deformed in the direction perpendicular to the longitudinal direction of the connecting portion of the shock absorbing portion, that is, in the thickness direction of the shock absorbing portion, and each shock absorbing portion is the width of the shock absorbing portion. Does not deform in the direction. Also in the second embodiment, when the nuclear fuel storage container in which the spent fuel assembly 9 is stored falls with the lid member facing downward, the impact force received by the lid member 4A by the spent fuel assembly 9 causes each impact. The shock absorbing portion of the absorbing device is deformed in the longitudinal direction of the connecting portion of the shock absorbing portion, that is, the thickness direction of the shock absorbing portion, and each shock absorbing portion is not deformed in the width direction of the shock absorbing portion.

  It is desirable that the impact absorbing device used in each embodiment is made of a highly ductile metal or resin material. By manufacturing a shock absorber using a light metal such as aluminum or a heat-resistant plastic, a lighter shock absorber can be obtained.

  Each of the nuclear fuel storage containers of Examples 2 to 7 is a nuclear fuel storage container that stores spent fuel assemblies generated in other nuclear reactors such as a pressurized water reactor, similarly to each of the fuel storage containers 1 of Example 1. Can also be applied. Moreover, each nuclear fuel storage container of Examples 1-7 can be applied not only to the spent fuel assembly 9 but also to transportation of a new fuel assembly after manufacture.

  1, 1A, 1B, 1C, 1D, 1E, 1F ... Nuclear fuel storage container, 2 ... Container body, 3 ... Basket, 4A, 4B, 4C ... Lid member, 5, 5A, 5B, 5C, 5D, 5E, 5F ... Shock absorbing device, 6, 6A, 6B ... connecting part, 7, 7A, 7B, 7C, 7D, 7E, 7F ... shock absorbing part, 9 ... spent fuel assembly, 10 ... fuel rod, 11 ... lower tie plate, DESCRIPTION OF SYMBOLS 12 ... Upper tie plate, 13 ... Handle, 15 ... Channel box, 16, 16A, 16B, 16C, 16D, 16E, 16F ... Bending part, 17A, 17B ... Side wall part, 18 ... Notch part.

Claims (7)

A container body whose lower end is sealed and whose upper end is opened, a basket which is installed in the container body and defines a plurality of storage areas of the fuel assembly, and is detachably attached to the upper end of the container body A lid member, and an impact absorbing device disposed between the fuel assembly and the lid member in a state where the fuel assembly is housed in each of the housing regions,
The shock absorbing device has a connecting portion and a plurality of shock absorbing portions connected to the connecting portion,
Each impact absorbing portion includes a plate-like side wall portion connected to the connecting portion, and a bent portion that is continuous with the side wall portion and faces the fuel assembly,
The shock absorbing device has a pair of the connecting portions extending along a plurality of the storage areas arranged in a line , the shock absorbing portion has a U shape, and the shock absorbing portions face each other. A nuclear fuel storage container, wherein each end portion of the side wall portion is separately connected to the pair of connecting portions, and the bent portion is connected to the side wall portions. The width direction of the side wall portion, the nuclear fuel container according to claim 1 which is in the longitudinal direction of the a direction in which the plurality of storage areas arranged in a row extending the connection portion. Nuclear fuel container according to claim 1 or 2, wherein the bent portion has a curved surface. The nuclear fuel storage container according to claim 1 , wherein the side wall has a bellows shape. The nuclear fuel storage container according to claim 1 , wherein the width of one of the opposing side wall portions is narrower than the width of the other side wall portion. 2. The nuclear fuel storage container according to claim 1 , wherein a cutout portion extending in a longitudinal direction of the connecting portion, which is a direction in which the plurality of storage regions arranged in a row extends, is formed in the side wall portion. As nuclear fuel storing container, storage method of the nuclear fuel container of a fuel assembly using the nuclear fuel container according to any one of claims 1 to 6.

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