JP2012013501A - Nuclear fuel storage rack - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a nuclear fuel storage rack capable of preventing damage of support leg parts or a storage pit even if locking occurs in an earthquake.SOLUTION: A nuclear fuel storage rack B provided in water in a storage pit 3 in the state of storing nuclear fuel aggregate comprises: a cell storage part 6 for storing and holding multiple rack cells housing the nuclear fuel aggregate; and multiple support leg parts 10 for connecting to the cell storage part 6 and supporting the cell storage part 6. The support leg part 10 comprises: a leg part 11 projecting downward from the cell storage part 6; and a board-like pedestal part 12 which is provided by connecting to a lower end of the leg part 11, is grounded on a bottom surface 3b of the storage pit 3 and supports the cell storage part 6. The pedestal part 12 is provided by movably connecting to the leg part 11.

Description

  The present invention relates to a nuclear fuel storage rack that is stored in a state where a nuclear fuel assembly is housed in water in a storage pit of a nuclear fuel storage facility.

  For example, spent nuclear fuel (used nuclear fuel rods) generated at a nuclear power plant is stored and stored in a nuclear fuel storage facility. Further, as shown in FIG. 16, the spent nuclear fuel is accommodated in a vertical cell (rack cell) 1 of a fuel storage rack A in a state of being accommodated in a rectangular tube as a nuclear fuel assembly, and a storage pit 3 of a nuclear fuel storage facility 2 is stored. Stored within. At this time, water is stored in the storage pit 3, and a plurality of nuclear fuel storage racks A (nuclear fuel assemblies) are arranged and stored in the water so that the decay heat is cooled and removed below the criticality. It holds and shields radiation.

  Further, conventionally, the nuclear fuel storage rack A is fixed to the side wall 3a of the storage pit 3 via a support (anchor), and is stored in a state of being supported by the support and the storage pit 3 (see, for example, Patent Document 1). . However, when the nuclear fuel storage rack A is fixed to the storage pit 3 in this way, there is a possibility that the support load becomes large during a large earthquake and the nuclear fuel storage rack A cannot be supported.

  For this reason, a method for storing the nuclear fuel storage rack A without fixing it to the side wall 3a or the bottom (bottom) 3b of the storage pit 3 has been proposed and put into practical use. In the nuclear fuel storage facility 2 in which the nuclear fuel storage rack A is stored without being fixed to the side wall 3a or the bottom 3b of the storage pit 3, the nuclear fuel storage rack A can slide relative to the bottom (bottom) 3b of the storage pit 3. The horizontal force acting upon the occurrence of an earthquake is absorbed by the sliding of the nuclear fuel storage rack A together with the fluid added damping effect of water.

  When the nuclear fuel storage rack A is configured to slide in the event of an earthquake as described above (that is, when the nuclear fuel storage rack A is configured as a free-standing rack), the nuclear fuel storage rack A is: For example, as shown in FIGS. 17, 18, and 19, the base plate 4, four support legs 5 that are disposed on the four corner portions of the base plate 4 and project downward, and above the base plate 4, are provided. It is provided and has a cell storage portion 6 that houses and holds a plurality of vertical cells (rack cells) 1 and is formed in a substantially rectangular box shape. Further, as shown in FIG. 19, the support leg 5 includes a leg 7 that extends in the vertical direction and a pedestal 8 that is integrally fixed to the lower end of the leg 7. Furthermore, the cell storage unit 6 is formed by assembling a support 6a, a cross member 6b, and an oblique member (stay) 6c as shown in FIG. 17, or surrounded by the support 6a and the cross member 6b as shown in FIG. It is formed by providing an outer peripheral plate 6d in the surface.

Japanese Patent Laid-Open No. 62-190494

  However, when the nuclear fuel storage rack A is configured to slide during an earthquake, when a large earthquake occurs, the nuclear fuel storage rack A stored in the storage pit 3 is locked as shown in FIG. When rocking occurs and the nuclear fuel storage rack A tilts, the connecting portion between the leg portion 7 and the pedestal portion 8 of the support leg portion 5 and the connecting portion between the leg portion 7 and the cell storage portion 6 (base plate 4) are provided. A large stress is generated locally to cause damage to the support leg 5, or the lifted support leg 5 collides with the bottom surface 3 b of the storage pit 3 to damage the support leg 5 or the bottom surface 3 b of the storage pit 3. Could occur.

  In view of the above circumstances, the present invention has an object to provide a nuclear fuel storage rack that can prevent damage to support legs and storage pits even when rocking occurs during an earthquake. To do.

  In order to achieve the above object, the present invention provides the following means.

  A nuclear fuel storage rack according to the present invention is a nuclear fuel storage rack installed in water in a storage pit in a state in which a nuclear fuel assembly is stored, and stores and holds a plurality of rack cells that store the nuclear fuel assembly. A cell storage section, and a plurality of support legs connected to the cell storage section to support the cell storage section, and the support leg protrudes downward from the cell storage section; and Provided to be connected to the lower end of the leg part, and provided with a disk-like pedestal part that is grounded to the bottom of the storage pit and supports the cell storage part, and the pedestal part is provided movably connected to the leg part. It is characterized by.

  In this invention, since the pedestal part is movably connected to the leg part of the support leg part (since the pedestal part is movable), a horizontal force acts during an earthquake and a tipping moment acts on the nuclear fuel storage rack. At this time, the pedestal part tilts (moves) with respect to the leg part. This makes it possible to suppress the occurrence of a locking phenomenon and to connect the legs of the support leg and the pedestal as compared with the case where the leg and the pedestal are integrally fixed as in the prior art. It is possible to prevent a large stress from being locally generated at the connection portion between the portion or the leg portion and the cell storage portion.

  Further, when the nuclear fuel storage rack is locked, the pedestal of the support leg is lifted from the bottom of the storage pit, and the pedestal is movably connected to the leg when the pedestal comes into contact with the bottom of the storage pit again. Therefore, the pedestal part abuts against the bottom surface of the storage pit while tilting, and it is possible to reduce (relax) the impact acting on the pedestal part (support leg) and the bottom surface of the storage pit.

  Further, in the nuclear fuel storage rack of the present invention, the support leg portion is arranged with the axial direction in the vertical direction, the upper end side is connected to the leg portion, and the lower end side is connected to the pedestal portion to the leg portion. A connecting member for connecting a pedestal portion, wherein the connecting member is formed with a spherical portion on at least one of the upper end side and the lower end side, and at least one of the pedestal portion and the leg portion is recessed on the inner surface; A connecting hole having a spherical spherical seat is formed, the spherical portion is slidably engaged with the spherical seat of the connecting hole, and the pedestal portion is movably connected to the leg portion. Is desirable.

  In this invention, the spherical portion of the connecting member is engaged with a connecting hole formed in the pedestal portion or the leg portion, the spherical portion is slidably engaged with the spherical seat of the connecting hole, and the pedestal portion is movable to the leg portion. Because it is connected, a horizontal force acts in the event of an earthquake, and the nuclear fuel storage rack tilts, and the spherical part slides on the spherical seat and rotates relative to it, ensuring that the pedestal part is relative to the leg part. Can be tilted (movable). As a result, it is possible to suppress the occurrence of the rocking phenomenon, and that a large stress is locally generated at the connecting portion between the leg portion of the support leg and the pedestal portion and the connecting portion between the leg portion and the cell storage portion. It becomes possible to prevent. In addition, when the nuclear fuel storage rack is locked and the pedestal of the support leg is lifted from the bottom surface of the storage pit, the pedestal part (support leg) and the storage pit are brought into contact with the bottom surface of the storage pit again. It is possible to reliably reduce the impact acting on the bottom surface of the.

  Furthermore, in the nuclear fuel storage rack of the present invention, the connecting member includes the spherical portion on the lower end side, and a rod-shaped male screw portion formed by threading an external screw on the outer peripheral surface on the upper end side. And formed with a rotating tool mounting hole opened at the upper end surface and drilled at the center of the axis, and the leg portion has a connecting plate with a female screw hole drilled at the lower end. The connecting member is formed by screwing the male screw part into the female screw hole of the connecting plate, attaching a rotary tool to the rotary tool attaching hole, and rotating forward and backward around an axis line. It is more preferable that the leg portion is connected to the leg portion so as to freely move forward and backward.

  In the present invention, with a pedestal portion grounded to the bottom of the storage pit and a nuclear fuel storage rack installed in the storage pit, a rotary tool such as a hexagon wrench is inserted into the rotary tool mounting hole from above the storage pit. The support leg can be expanded and contracted in the vertical direction by rotating the attachment and rotating tool to rotate the connecting member forward and backward around the axis. This makes it possible to easily adjust the height of the nuclear fuel storage rack. After the height adjustment, a loosening member is installed in the female screw hole of the connection board, etc. so that there is no slack between the male screw part and the female screw hole (between the connection member and the connection board) when an earthquake occurs. It is preferable to prevent the occurrence.

  Also, in the conventional support leg portion in which the leg portion and the pedestal portion are integrally fixed, a rotary tool mounting hole is formed in the leg portion, and this leg portion is screwed into the cell storage portion and connected. It is possible to adjust the height using a rotary tool, but in this case, the leg part is rotated around the axis with the rotary tool, and the pedestal part fixed integrally is also rotated. This will damage the bottom of the storage pit. On the other hand, in the present invention, when the rotary tool is rotated, the spherical portion can slide on the spherical seat of the connecting hole to rotate only the connecting member, and the pedestal portion is held as it is. be able to. For this reason, there is no possibility of damaging the bottom of the storage pit.

In the nuclear fuel storage rack according to the present invention, it is further preferable that the support leg portion includes an elastic body between a lower end surface of the leg portion and an upper end surface of the pedestal portion.
The elastic body includes not only a rubber and a spring but also a vibration damping mechanism (damper).

  In this invention, since the elastic body is interposed between the lower end surface of the leg portion and the upper end surface of the pedestal portion, a horizontal force acts during an earthquake and a tipping moment acts on the nuclear fuel storage rack, and the leg portion On the other hand, when the pedestal portion tilts (moves), the overturning moment can be absorbed by the elastic body, and the occurrence of the rocking phenomenon can be suppressed.

  In addition, when the pedestal of the support leg that has been lifted due to the occurrence of rocking in the nuclear fuel storage rack comes into contact with the bottom surface of the storage pit again, the impact can be absorbed by the elastic body, thereby reducing the impact more reliably. It becomes possible.

  Furthermore, in the nuclear fuel storage rack of the present invention, the bottom portion of the storage pit is formed with a concrete slab, and the pedestal portion has an area of a ground contact surface that is grounded to the bottom surface of the storage pit, It is desirable that the rack is set and formed on the basis of a load acting on the concrete slab when the rack is raised and floats from the bottom surface of the storage pit and again comes into contact with the bottom surface of the storage pit.

  In this invention, it becomes a pedestal part larger than before by setting the area of the contact surface based on the load acting on the concrete slab. For this reason, when rocking occurs and the pedestal part floats from the bottom surface of the storage pit and again comes into contact with the bottom surface of the storage pit, the surface pressure generated on the bottom surface of the storage pit can be reduced and the concrete is damaged. Can be prevented. Further, since the adhesion between the movable pedestal and the bottom surface of the storage pit can be improved, the stability of the nuclear fuel storage rack can be improved.

  In the nuclear fuel storage rack according to the present invention, the connection hole includes the spherical seat at the bottom and extends in the vertical direction, and the spherical portion engaged with the connection hole is formed to be movable in the vertical direction. In addition, at least one of the pedestal part and the leg part in which the connection hole is formed, a flow path through which water flows through the connection hole and the outside may be formed.

  In this invention, with the nuclear fuel storage rack installed in the water in the storage pit, water enters the connection hole through the flow path. In the event of an earthquake, the nuclear fuel storage rack tilts due to the horizontal force, and the pedestal portion tilts (moves), and the water in the connection hole is ejected to the outside through the flow path, or the water in the storage pit is It enters the connecting hole through the flow path. As described above, the pedestal portion tilts due to locking or the like, and water flows in and out from the connection hole to the outside and from the outside to the connection hole.

  Further, when rocking occurs and the pedestal part is lifted from the bottom surface of the storage pit, the spherical part of the connection member moves upward in the connection hole, and water flows into the spherical seat side (downward) of the connection hole. When the raised pedestal part comes into contact with the bottom surface of the storage pit again, the spherical part moves downward in the connection hole, and the water between the spherical seat and the spherical part of the connection hole becomes a cushion, and the impact force is increased. Can be reduced. Furthermore, since the spherical portion moves downward in the connecting portion in this way and the water in the connecting hole is ejected from the flow path to the outside, the impact force can be reduced also by the fluid resistance of the water.

  Furthermore, in the nuclear fuel storage rack of the present invention, it is more preferable that a groove serving as a flow path for water in the connection hole is formed on the outer peripheral surface of the spherical body.

  In this invention, by providing a groove on the outer peripheral surface to form a spherical portion, when the pedestal portion tilts (moves), water in the connection hole flows through the groove of the spherical portion as a flow path. It becomes possible to obtain a rocking deterrent effect by the fluid resistance of the flowing water. Also, when rocking occurs and the pedestal part floats from the bottom surface of the storage pit and the spherical part moves in the connection hole, the water in the connection hole flows using the groove of the spherical part as a flow path, and the spherical part smoothly flows. It can be moved. Furthermore, when the pedestal part comes into contact with the bottom surface of the storage pit again, the water in the connecting hole flows through the groove of the spherical part as a flow path, and the impact resistance can be obtained by the fluid resistance of this water. It becomes possible.

  In the nuclear fuel storage rack according to the present invention, it is further preferable that a passage for communicating the connection hole with the outside is formed to open to a grounding surface of the pedestal portion that is grounded to a bottom surface of the storage pit. .

  In this invention, the pedestal part that has been rocked and lifted up again comes into contact with the bottom surface of the storage pit by forming a flow path that opens to the grounding surface of the pedestal part and communicates the connection hole with the outside. At this time, the water in the connecting hole can be ejected from the ground contact surface of the pedestal portion toward the bottom surface of the storage pit, and the impact can be effectively reduced (relaxed) by the ejected water.

  Furthermore, in the nuclear fuel storage rack of the present invention, the connection hole includes the spherical seat at the bottom and extends in the vertical direction, and the spherical portion engaged with the connection hole is formed to be movable in the vertical direction. In addition, a viscoelastic body may be disposed in the connection hole.

  In this invention, by arranging a viscoelastic body instead of water in the connecting hole, the pedestal part tilts (moves) and the spherical part moves in the connecting hole and generates viscoelastic resistance. The viscoelastic resistance of the viscoelastic body makes it possible to obtain a rocking suppression effect and an impact relaxation effect.

  According to the nuclear fuel storage rack of the present invention, when a horizontal force acts on the nuclear fuel storage rack and an overturning moment acts on the nuclear fuel storage rack, the pedestal portion tilts (moves) with respect to the leg portion, and the rocking phenomenon occurs. It is possible to suppress the occurrence, and it is possible to prevent the occurrence of large stress locally at the connecting part of the leg part of the support leg and the base part and the connecting part of the leg part and the cell storage part. Become. As a result, it is possible to prevent damage to the connecting portion between the leg portion and the pedestal portion of the support leg portion and the connecting portion between the leg portion and the cell storage portion.

  In addition, when the nuclear fuel storage rack is locked and the pedestal of the support leg is lifted from the bottom surface of the storage pit, the pedestal part (support leg) and the storage pit are brought into contact with the bottom surface of the storage pit again. It is possible to reduce (relieve) the impact acting on the bottom surface of the plate. As a result, it is possible to prevent the impact due to the locking and damage to the support leg and the bottom surface of the storage pit.

It is a figure which shows the rack for nuclear fuel storage which concerns on 1st Embodiment of this invention. It is a figure which shows the support leg part of the rack for nuclear fuel storage which concerns on 1st Embodiment of this invention. It is a figure which shows the state in which the base part of the support leg part of the nuclear fuel storage rack which concerns on 1st Embodiment of this invention inclined relatively with respect to the leg part. It is a figure which shows the state in which the base part of the support leg part of the nuclear fuel storage rack which concerns on 1st Embodiment of this invention inclined relatively with respect to the leg part. It is a figure which shows the state which installed the rack for nuclear fuel storage which concerns on 1st Embodiment of this invention in the storage pit where the horizontal accuracy of a bottom face is bad. It is a figure which shows the modification of the rack for nuclear fuel storage (support leg part) which concerns on 1st Embodiment of this invention. It is a figure which shows the modification of the rack for nuclear fuel storage (support leg part) which concerns on 1st Embodiment of this invention. FIG. 8 is a view showing a state in which a horizontal force acts on the nuclear fuel storage rack of FIG. It is a figure which shows the modification of the rack for nuclear fuel storage (support leg part) which concerns on 1st Embodiment of this invention. It is a figure which shows the modification of the rack for nuclear fuel storage (support leg part) which concerns on 1st Embodiment of this invention. It is a figure which shows the support leg part of the rack for nuclear fuel storage which concerns on 2nd Embodiment of this invention. It is a figure which shows the state in which the base part of the support leg part of the nuclear fuel storage rack which concerns on 2nd Embodiment of this invention inclined relatively with respect to the leg part. It is a figure which shows the modification of the rack for nuclear fuel storage (support leg part) which concerns on 2nd Embodiment of this invention. It is a figure which shows the modification of the rack for nuclear fuel storage (support leg part) which concerns on 2nd Embodiment of this invention. It is a figure which shows the modification of the rack for nuclear fuel storage (support leg part) which concerns on 2nd Embodiment of this invention. It is a figure which shows the storage pit of the nuclear fuel storage facility which stored the rack for nuclear fuel storage. It is a figure which shows the conventional rack for nuclear fuel storage. It is a figure which shows the conventional rack for nuclear fuel storage. It is a figure which shows the conventional rack for nuclear fuel storage. It is a figure showing the state where rocking occurred in the conventional rack for nuclear fuel storage.

  Hereinafter, a nuclear fuel storage rack according to a first embodiment of the present invention will be described with reference to FIGS. The present embodiment relates to a nuclear fuel storage rack for storing and storing spent nuclear fuel generated at, for example, a nuclear power plant in water in a storage pit of a nuclear fuel storage facility.

  The nuclear fuel storage rack B of the present embodiment is a self-supporting rack, and, like the conventional nuclear fuel storage rack A, as shown in FIG. 1 (see FIGS. 16 to 19), a plurality of nuclear fuel assemblies 1 are accommodated. The cell storage unit 6 that stores and holds the rack cell 1 and a plurality of support legs 10 that are connected to the cell storage unit 6 (base plate 4) and support the cell storage unit 6 are configured.

  On the other hand, in the nuclear fuel storage rack B of the present embodiment, as shown in FIGS. 1 and 2, the support leg 10 includes a leg 11 having a U-shaped cross section projecting downward from the base plate 4, and a leg. 11 is connected to the lower end of the storage pit 3, is grounded to the bottom surface 3 b of the storage pit 3, and includes a disk-shaped pedestal portion 12 that supports the cell storage portion 6. In the present embodiment, the legs 11 are formed in a U-shaped cross section in order to secure a water flow path for cooling the nuclear fuel.

  In the present embodiment, as shown in FIG. 2, the support leg 10 is arranged such that the axis O <b> 1 direction is arranged in the vertical direction, the upper end side is connected to the leg part 11, and the lower end side is connected to the pedestal part 12. The connecting member 13 that connects the pedestal portion 12 to the portion 11, and the elastic body 14 disposed between the lower end surface 11 a of the leg portion 11 and the upper end surface 12 a of the pedestal portion 12 are configured.

  The pedestal portion 12 is made of, for example, stainless steel and has a substantially disc shape, and is formed with a connecting hole 15 that is recessed from the upper end surface 12a toward the lower end surface (grounding surface) 12b on the axis O1. Moreover, the inner surface (spherical seat 15a) of the connecting hole 15 is formed in a concave spherical shape. Further, the pedestal portion 12 is divided into an upper portion 12c and a lower portion 12d with a horizontal plane passing through the center of the coupling hole 15 as a boundary, and the upper portion 12c is detachably attached to the lower portion 12d by bolts.

  The connecting member 13 is provided with a spherical portion 13a on the lower end side and a rod-like male screw portion 13b formed on the outer peripheral surface by threading an external screw on the upper end side. Further, the male screw portion 13b is formed with a rotating tool mounting hole 13c having a hexagonal cross section, for example, which is opened at the upper end surface and drilled at the center of the axis O1 toward the lower end.

  The spherical portion 13a is formed larger than the hemisphere, that is, is integrally formed with the male screw portion 13b so that the center thereof is disposed below the lower end of the male screw portion 13b in the direction of the axis O1. Furthermore, the spherical portion 13a is formed so that the outer diameter thereof is larger than the outer diameter of the male screw portion 13b, and the outer diameter is smaller by a predetermined tolerance than the inner diameter of the connecting hole 15 of the pedestal portion 12. It is formed with.

  Further, the leg portion 11 is formed with a connecting plate 16 having a female screw hole 16a formed at the lower end thereof, and the connecting member 13 has a male screw portion 13b in the female screw hole 16a of the connecting plate 16. It is screwed and connected to the leg portion 11 with the axis O1 direction directed in the vertical direction. The connecting member 13 is provided by screwing the male screw portion 13b into the female screw hole 16a of the connecting plate 16, so that the rotary tool 17 is attached to the rotary tool attaching hole 13c so By rotating in the reverse direction, it is connected to the leg portion 11 so as to be movable back and forth in the vertical direction.

  Further, the base portion 12 is connected to the connecting member 13 by engaging the spherical portion 13 a of the connecting member 13 with the connecting hole 15. At this time, the spherical portion 13a is slidably engaged with the spherical seat 15a of the connecting hole 15, so that the pedestal portion 12 is connected via the connecting member 13 and thus the connecting member 13 as shown in FIGS. It is connected to the leg part 11 so that it can be tilted (oscillated) (movably connected). Further, at least one of the outer peripheral surface of the spherical portion 13a and the inner surface (spherical seat 15a) of the connecting hole 15 is coated with graphite coating or the like, and the outer peripheral surface of the spherical portion 13a and the inner surface 15a of the connecting hole 15 are adhered by this coating. The pedestal portion 12 is configured to move reliably with respect to the leg portion 11.

  The elastic body 14 provided between the lower end surface 11a of the coupling board 16 and the upper end surface 12a of the pedestal portion 12 is, for example, rubber, a disc spring, a leaf spring, or a vibration damping mechanism (damper), and the pedestal portion 12 is a leg portion. When tilted with respect to 11, the lower end surface 11a of the connecting plate 16 and the upper end surface 12a of the base 12 facing each other are urged to return the base 12 to the initial posture.

  Next, the operation and effect of the nuclear fuel storage rack B of the present embodiment having the above-described configuration will be described.

  First, the nuclear fuel storage rack B of the present embodiment is stored in the storage pit 3 of the nuclear fuel storage facility 2 in a state where the nuclear fuel assembly is housed in the rack cell 1. At this time, water is stored in the storage pit 3, and the nuclear fuel storage rack B is installed by immersing the base 12 of the support leg 10 in contact with the bottom surface 3 b of the storage pit 3.

  And after installing in the storage pit 3 in this way, it may be necessary to adjust the height of the nuclear fuel storage rack B. In the nuclear fuel storage rack B of the present embodiment, the connecting member 13 is used. A rotary tool attachment hole 13c is provided in the upper end surface of the (male screw portion 13b). For this reason, a rotary tool 17 such as a hexagon wrench is inserted from above the storage pit 3 through the inside of the column 6a of the cell storage unit 6 through the rotary tool mounting hole 13c and attached, and the connecting member 13 is rotated forward and backward. The member 13 is screwed / unscrewed into the female screw hole 16a. As a result, the connecting member 13 and thus the pedestal portion 12 advance and retract in the vertical direction, the support leg portion 10 expands and contracts, and the height of the nuclear fuel storage rack B can be adjusted.

  Also, in the conventional support leg portion 5 in which the leg portion 7 and the pedestal portion 8 are integrally fixed, a rotary tool mounting hole 13c is formed in the leg portion 7, and the leg portion 7 is screwed into the cell storage portion 6 or the like. Thus, the height can be adjusted by using the rotary tool 17. However, in this case, the leg portion 7 is rotated around the axis O1 with the rotary tool 17, and the pedestal portion 8 fixed integrally is also rotated. It will hurt you. On the other hand, in the support leg portion 10 of the present embodiment, when the rotary tool 17 is rotated, the spherical portion 13a slides on the spherical seat 15a of the connecting hole 15 and only the connecting member 13 rotates, and the pedestal. The part 12 is held as it is. For this reason, there is no possibility of damaging the bottom surface 3b of the storage pit 3.

  On the other hand, when a horizontal force acts upon the occurrence of an earthquake, the nuclear fuel storage rack B slides and absorbs the horizontal force together with the fluid-added damping effect of water in the storage pit 3. Further, when a falling moment is applied to the nuclear fuel storage rack B due to a horizontal force during an earthquake, the spherical portion 13a of the connecting member 13 slides in the connecting hole 15 of the pedestal portion 12, and the connecting member 13 and thus the leg portion 11 are moved. On the other hand, the pedestal 12 is tilted (moved) relatively. For this reason, compared with the case where the conventional leg part 7 and the base part 8 are integrally fixed, generation | occurrence | production of a rocking phenomenon is suppressed.

  Further, in the nuclear fuel storage rack B of the present embodiment, since the elastic body 14 is interposed between the connecting board 16 and the pedestal portion 12, the elastic body 14 is elastic when the pedestal portion 12 is tilted. Absorbs the falling moment by demonstrating the effect and damper effect. Therefore, also from this point, the occurrence of the rocking phenomenon is suppressed.

  Even when the nuclear fuel storage rack B is tilted due to the occurrence of rocking, the pedestal 12 is tilted with respect to the leg 11, so that the connecting portion between the leg 11 and the pedestal 12 and the leg 11 A large stress is not locally generated in the connection portion of the cell storage unit 6 (base plate 4). For this reason, it is prevented that the leg part 11 and the base part 12 of the supporting leg part 10 are damaged.

  Further, when rocking occurs and the pedestal portion 12 is lifted from the bottom surface 3b of the storage pit 3 and the pedestal portion 12 comes into contact with the bottom surface 3b of the storage pit 3 again, the pedestal portion 12 tilts while the storage pit 3 The contact with the bottom surface 3b reduces the impact acting on the pedestal portion 12 (support leg portion 10) and the bottom surface 3b of the storage pit 3. Further, when the pedestal portion 12 is lifted from the bottom surface 3b of the storage pit 3 due to the locking and the pedestal portion 12 contacts the bottom surface 3b of the storage pit 3 while tilting again, the impact is absorbed by the elastic body 14. For this reason, the elastic body 14 also reduces the impact on the pedestal 12 (support leg 10) and the bottom surface 3b of the storage pit 3. Therefore, it is possible to prevent the impact due to the locking and damage to the support leg 10 and the bottom surface 3b of the storage pit 3 from occurring.

  Therefore, in the nuclear fuel storage rack B of the present embodiment, the pedestal 12 is movably connected to the leg 11 of the support leg 10 (since the pedestal 12 is movable), so that a horizontal force is applied during an earthquake. When the overturning moment is applied to the nuclear fuel storage rack B, the pedestal portion 12 tilts (moves) with respect to the leg portion 11. Thereby, compared with the case where the leg part 7 and the pedestal part 8 are integrally fixed as in the prior art, it is possible to suppress the occurrence of the locking phenomenon, and the leg part 11 of the support leg part 10 It is possible to prevent a large stress from being locally generated at the connecting portion of the pedestal portion 12 and the connecting portion between the leg portion 11 and the cell storage portion 6. Therefore, it is possible to prevent damage to the connecting portion between the leg portion 11 and the pedestal portion 12 of the supporting leg portion 10 and the connecting portion between the leg portion 11 and the cell storage portion 6.

  Further, when the nuclear fuel storage rack B is locked, the pedestal portion 12 is lifted from the bottom surface 3b of the storage pit 3 and the pedestal portion 12 comes into contact with the bottom surface 3b of the storage pit 3 again. Since the pedestal portion 12 is tilted, the pedestal portion 12 abuts against the bottom surface 3b of the storage pit 3 and the impact acting on the pedestal portion 12 (support leg portion 10) and the bottom surface 3b of the storage pit 3 is reduced. (Relaxing) becomes possible. As a result, it is possible to prevent damage from occurring on the support leg 10 and the bottom surface 3b of the storage pit 3 due to an impact due to locking.

  Further, in the nuclear fuel storage rack B of the present embodiment, the spherical portion 13a of the connecting member 13 is engaged with the connecting hole 15 formed in the pedestal portion 12, and the spherical portion 13a slides on the spherical seat 15a of the connecting hole 15. The pedestal portion 12 is movably connected to the leg portion 11 by engaging with each other. For this reason, a horizontal force acts during an earthquake and the nuclear fuel storage rack B tilts, and the spherical portion 13a slides on the spherical seat 15a and rotates relatively, so that the pedestal portion 12 is securely attached to the leg portion 11. Can be relatively tilted (movable). As a result, it is possible to suppress the occurrence of the rocking phenomenon, and a large local stress is applied to the connecting portion between the leg portion 11 and the pedestal portion 12 of the supporting leg portion 10 and the connecting portion between the leg portion 11 and the cell storage portion 6. Can be prevented from occurring. Further, when the nuclear fuel storage rack B is locked, the pedestal portion 12 is lifted from the bottom surface 3b of the storage pit 3, and the pedestal portion 12 (support leg portion) is brought into contact with the bottom surface 3b of the storage pit 3 again. 10) and the impact acting on the bottom surface 3b of the storage pit 3 can be reliably reduced.

  Further, with the pedestal portion 12 grounded to the bottom surface 3b of the storage pit 3 and the nuclear fuel storage rack B installed in the storage pit 3, a rotary tool 17 such as a hexagon wrench is inserted into the rotary tool mounting hole from above the storage pit 3. It is possible to extend and retract the support leg 10 in the vertical direction by inserting and attaching to 13c and rotating the rotary tool 17 to rotate the connecting member 13 forward and backward around the axis O1. This makes it possible to easily adjust the height of the nuclear fuel storage rack B.

  Further, when the rotary tool 17 is rotated, the spherical portion 13a can slide on the spherical seat 15a of the connecting hole 15 to rotate only the connecting member 13, and the pedestal portion 12 can be held as it is. Can do. For this reason, there is no possibility of damaging the bottom surface 3b of the storage pit 3.

  Further, since the elastic body 14 is interposed between the lower end surface 11a of the leg portion 11 and the upper end surface 12a of the pedestal portion 12, a horizontal force acts during an earthquake and a tipping moment acts on the nuclear fuel storage rack B. When the pedestal portion 12 tilts with respect to the leg portion 11, the overturning moment can be absorbed by the elastic body 14, and the occurrence of the rocking phenomenon can be suppressed.

  In addition, when the pedestal 12 that has been lifted due to rocking in the nuclear fuel storage rack B comes into contact with the bottom surface 3b of the storage pit 3 again, the impact can be absorbed by the elastic body 14, and the impact can be reduced more reliably. It becomes possible to do.

  Further, since the pedestal portion 12 is movably connected to the leg portion 11, when the nuclear fuel storage rack B is installed in the storage pit 3, as shown in FIG. By tilting the pedestal portion 12 with respect to the portion 11, the nuclear fuel storage rack B can be stably installed.

  The first embodiment of the nuclear fuel storage rack according to the present invention has been described above. However, the present invention is not limited to the first embodiment described above, and can be changed as appropriate without departing from the spirit of the present invention.

  For example, in the present embodiment, a spherical portion 13a is provided on the coupling member 13 that is screwed into the female screw hole 16a of the coupling board 16 and attached to be movable in the vertical direction, and this spherical portion 13a is connected to the base portion 12. It is assumed that the base 12 is movably connected to the leg 11 by engaging with the hole 15. On the other hand, in the nuclear fuel storage rack B of the present invention, for example, as shown in FIG. 6, a connecting hole 16 having a spherical inner surface (spherical seat 15 a) is formed in the connecting plate 16, and the upper end surface of the pedestal portion 12. The spherical portion 13a is provided on the upper end side of the connecting member 13 (connecting portion) protruding upward in the axis O1 direction from 12a to form the pedestal portion 12, and the spherical portion 13a provided on the pedestal portion 12 side is connected to the connecting plate 16 side. The base 12 may be movably connected to the leg 11 by engaging with the connecting hole 15.

  In this case, when rocking occurs and the nuclear fuel storage rack B tilts, the leg portion 11 and the pedestal portion 12 tilt relative to each other. Therefore, it is possible to prevent the occurrence of breakage at the connecting portion between the leg portion 11 and the base portion 12. Further, when the pedestal portion 12 is lifted from the bottom surface 3b of the storage pit 3 due to rocking and the pedestal portion 12 again comes into contact with the bottom surface 3b of the storage pit 3, the bottom surface of the storage pit 3 is tilted while the pedestal portion 12 is tilted. Since it contacts 3b, it can prevent that a big impact acts on the base part 12 (supporting leg part 10) like this embodiment. Furthermore, the nuclear fuel storage rack B in which the nuclear fuel assemblies are stored in the rack cell 1 is installed in the water of the storage pit 3 for a long period of, for example, several decades. Foreign matter is unlikely to enter between the outer peripheral surface of the spherical portion 13a and the inner surface 15a of the connecting hole 15 on the connecting plate 16 side, and the base portion 12 is reliably maintained so as to be suitably tilted with respect to the leg portion 11 over a long period of time. Can do.

  In connection with this, for example, as shown in FIG. 7, the connecting plate 16 and the pedestal portion 12 are each provided with a connecting hole 15 and spherical members 13a are provided on both ends of the connecting member 13, and these spherical portions 13a are connected. The support leg 10 may be configured by engaging the board 16 and the connection hole 15 of the base 12. In this case, when a horizontal force acts during an earthquake, the cell storage unit 6 is swayed as shown in FIG. In addition, the cell storage unit 6 swaying in this way can suppress the horizontal vibration response level and reduce the amount of rocking and slipping. Further, in this case, an elastic body 14 (spring / damper) is provided between the connecting board 16 and the base 12 so that the nuclear fuel storage rack B is self-supporting during the initial stationary state and is not excessively swayed. It is preferable to provide it.

  Furthermore, in the present embodiment, the spherical portion 13a and the connecting hole 15 with which the spherical portion 13a engages are formed in a spherical shape larger than the hemisphere. For example, as shown in FIG. 9, the spherical portion 13a is formed. The connecting hole 15 may be formed in a spherical shape smaller than the hemisphere. Even in this case, it is possible to attach the pedestal portion 12 to the leg portion 11 so as to be tiltable, and it is possible to obtain the same operational effects as in the present embodiment. Furthermore, when comprised in this way, the height dimension of the base part 12 can be restrained small.

  Further, conventionally, the bottom of the storage pit 3 is formed by installing a stainless steel plate on the concrete slab 18, rocking occurs, and the pedestal 12 is lifted from the bottom surface 3 b of the storage pit 3. There is a possibility that an excessive load acts on the concrete slab 18 when it abuts against the bottom surface 3b of the concrete and the concrete 18 is damaged. On the other hand, as shown in FIG. 10, the area of the ground contact surface 12b that is grounded to the bottom surface 3b of the storage pit 3 acts on the concrete slab 18 when contacting the bottom surface 3b of the storage pit 3 again as described above. The base 12 may be formed by setting based on the load.

  In this case, by setting the area of the ground contact surface 12b based on the load acting on the concrete slab 18, the pedestal portion 12 becomes larger than the conventional one. For this reason, when rocking occurs and the pedestal portion 12 abuts against the bottom surface 3b of the storage pit 3 again, the surface pressure generated on the bottom surface 3b of the storage pit 3 can be reduced, and the concrete 18 is damaged. It can be prevented from occurring. In addition, since the adhesiveness between the movable base 12 and the bottom surface 3b of the storage pit 3 can be improved, the stability of the nuclear fuel storage rack B can be improved.

  Next, a nuclear fuel storage rack according to a second embodiment of the present invention will be described with reference to FIG. 1, FIG. 11 and FIG. As in the first embodiment, the present embodiment relates to a nuclear fuel storage rack including a movable pedestal portion 12 and a support leg portion 10. For this reason, the same code | symbol is attached | subjected with respect to the structure similar to 1st Embodiment, and the detailed description is abbreviate | omitted.

  The nuclear fuel storage rack C of the present embodiment is a self-supporting rack, and includes a cell storage portion 6 and support leg portions 20 as shown in FIG. 1 as in the first embodiment. Further, as shown in FIG. 11, the support leg 20 of the nuclear fuel storage rack C according to the present embodiment has a connecting plate 16 provided with a female screw hole 16a having a female screw formed on the inner peripheral surface, as shown in FIG. The connecting member 13 composed of the male screw portion 13b and the spherical portion 13a is screwed and attached, and the spherical portion 13a of the connecting member 13 is engaged with the connecting hole 15 of the pedestal portion 12, so that the pedestal portion 12 is attached to the leg portion. 11 movably connected. Further, an elastic body 14 (not shown) is interposed between the connection board 16 and the pedestal portion 12.

  On the other hand, in the support leg portion 20 of the present embodiment, the connecting hole 15 has a spherical seat 15a at the bottom and extends in the vertical direction, and the spherical portion 13a engaged with the connecting hole 15 is formed to be movable in the vertical direction. Has been. The pedestal portion 12 in which the connection hole 15 is formed is formed with a flow path 21 through which the water W flows through the connection hole 12 and the outside. And in this embodiment, the flow path 21 which connects this connection hole 15 and the exterior is formed of the clearance gap between the connection member 13 and the upper part of the base part 12. FIG.

  In the nuclear fuel storage rack C of this embodiment configured as described above, as shown in FIG. 11 and FIG. 12, it is immersed in the water in the storage pit 3, and the pedestal 12 is grounded to the bottom surface 3 b of the storage pit 3. The water W enters the inside of the connection hole 15 through the flow path 21 in the state of being stored. Then, when an earthquake occurs, a horizontal force acts to cause rocking, the nuclear fuel storage rack C tilts and the pedestal part 12 tilts relatively, so that the connection between the leg part 11 and the pedestal part 12 is locally applied. It is possible to prevent a large stress from being generated.

  Furthermore, the pedestal 12 is tilted and the water W in the connection hole 15 is ejected from the flow path 21 in the gap above the connection member 13 and the pedestal 12, or the water W in the storage pit 3 It enters the connecting hole 15 through the flow path 21. In this way, the locking occurs, and the water W flows in and out of the connecting hole 15 from the outside and into the connecting hole 15 from the outside. Therefore, the locking of the water W is suppressed by the fluid resistance of the water W. At this time, the water W that has entered the connecting hole 15 flows out downward and upward of the connecting hole 15 through the gap between the spherical part 13a and the inner surface of the connecting hole 15 with the spherical part 13a in the connecting hole 15 therebetween. Enter. For this reason, the rocking | fluctuation suppression effect is acquired also by the fluid resistance of the water W at the time of distribute | circulating this clearance gap.

  Further, when rocking occurs and the pedestal portion 12 is lifted from the bottom surface 3 b of the storage pit 3, the spherical portion 13 a moves upward in the connection hole 15 and is connected through a gap between the spherical portion 13 a and the inner surface of the connection hole 15. Water W flows below the holes 15. When the pedestal portion 12 comes into contact with the bottom surface 3b of the storage pit 3 again, the spherical portion 13a moves downward in the connection hole 15, so that the space between the inner surface (spherical seat 15a) of the connection hole 15 and the spherical portion 15a is reduced. The water W becomes a cushion and the impact is alleviated. In addition, since the spherical portion 13a moves downward in the connection hole 15 in this way, the water W in the connection hole 15 is ejected to the outside from the flow path 21 above the connection member 13 and the pedestal portion 12. The impact is also reduced by the fluid resistance of the water W. Therefore, it is possible to prevent the impact due to the locking and damage to the support leg 20 and the bottom surface 3b of the storage pit 3 from occurring.

  Therefore, in the nuclear fuel storage rack C of the present embodiment, a horizontal force acts to cause the nuclear fuel storage rack C and the pedestal 12 to tilt (move) during an earthquake, and the water W in the connection hole 15 flows. The water W is ejected to the outside through the passage 21 or the water W in the storage pit 3 enters the connection hole 15 through the passage 21. Thereby, it becomes possible to suppress locking by the fluid resistance of the water W.

  In addition, when the pedestal portion 12 that has been lifted due to the rocking comes into contact with the bottom surface 3b of the storage pit 3 again, the spherical portion 13a moves downward in the connection hole 15 and is spherical with the spherical seat 15a of the connection hole 15. The water W between the parts 13a becomes a cushion, and the impact force can be reduced. Furthermore, since the spherical portion 13a moves downward in the connecting portion 15 in this way and the water W in the connecting hole 15 is ejected from the flow path 21 to the outside, the impact force is also reduced by the fluid resistance of the water W. can do.

  Therefore, also in the nuclear fuel storage rack C of the present embodiment, it is possible to suppress the occurrence of the rocking phenomenon as compared with the case where the leg portion 7 and the pedestal portion 8 are integrally fixed as in the prior art. At the same time, it is possible to prevent damage to the connecting portion between the leg portion 11 and the pedestal portion 12 of the supporting leg portion 20 and the connecting portion between the leg portion 11 and the cell storage portion 6.

  Moreover, it becomes possible to reduce the impact which acts on the base part 12 (support leg part 20) and the bottom face 3b of the storage pit 3, and an impact acts by rocking and damages the support leg part 20 and the bottom face 3b of the storage pit 3. Can be prevented from occurring.

  The second embodiment of the nuclear fuel storage rack according to the present invention has been described above. However, the present invention is not limited to the second embodiment described above, and includes changes to the first embodiment. Changes can be made as appropriate without departing from the scope.

  For example, in the present embodiment, water W flows in and out of the connection hole 15 through the gap (flow path 21) between the connection member 13 and the pedestal portion 12 and from the outside to the connection hole 15. In addition to this, the locking suppression effect and the impact relaxation effect are obtained, but in addition to this, as shown in FIG. 13, a groove 22 may be provided on the outer peripheral surface to form the spherical portion 13a. In this case, when the pedestal portion 12 is tilted, the water W in the connection hole 15 flows through the groove 22 of the spherical portion 13 a as a flow path, and the rocking suppression effect is exerted by the fluid resistance of the water W flowing through the groove 22. It becomes possible to obtain. Further, when rocking occurs and the pedestal portion 12 is lifted from the bottom surface 3b of the storage pit 3 and the spherical portion 13a moves in the connecting hole 15, the water in the connecting hole 15 is formed using the groove 22 of the spherical portion 13a as a flow path. W flows and the spherical portion 13a can be moved smoothly. Further, when the pedestal portion 12 comes into contact with the bottom surface 3b of the storage pit 3 again, the water W in the connection hole 15 flows through the groove 22 of the spherical portion 13a as a flow path. It is possible to obtain an impact relaxation effect.

  Further, as shown in FIGS. 14 and 15, a flow path 21 that communicates the connection hole 15 with the outside is formed in the upper end surface 12 a (or side surface) of the pedestal portion 12, or on the bottom surface 3 b of the storage pit 3. An opening is formed in the grounding surface 12b of the pedestal 12 to be grounded, and the water W flows into and out of the connecting hole 15 through the flow path 21 and from the outside to the connecting hole 15, thereby preventing a locking effect and reducing the impact. You may make it acquire an effect. When the flow path 21 is formed by opening the grounding surface 12 b of the pedestal portion 12, when the pedestal portion 12 that has been rocked and lifted comes into contact with the bottom surface 3 b of the storage pit 3 again, the connection hole 15 can be ejected from the ground contact surface 12b of the pedestal portion 12 toward the bottom surface 3b of the storage pit 3, and the impact can be effectively reduced by the ejected water W.

  Furthermore, in the present embodiment, the water in the storage pit enters the connection hole through the flow path that connects the connection hole and the outside, and the rocking suppression effect and the impact relaxation effect are obtained by the fluid resistance of this water. You may arrange | position by sealing a viscoelastic body in a connection hole. And, by arranging a viscoelastic body instead of water in the connecting hole in this way, the pedestal part can tilt and the spherical part moves in the connecting hole and can generate viscoelastic resistance, The viscoelastic resistance of the viscoelastic body makes it possible to obtain a rocking suppression effect and an impact relaxation effect.

1 Vertical cell (rack cell)
2 Nuclear fuel storage facility 3 Storage pit 3a Side wall 3b Bottom (bottom, bottom)
4 Base plate 5 Conventional support leg 6 Cell storage 6a Post 6b Cross member 6c Diagonal material (stay)
6d outer peripheral plate 7 conventional leg portion 8 conventional pedestal portion 10 support leg portion 11 leg portion 11a lower end surface 12 pedestal portion 12a upper end surface 12b lower end surface (grounding surface)
12c Upper part 12d Lower part 13 Connecting member 13a Spherical part 13b Male screw part 13c Rotary tool mounting hole 14 Elastic body 15 Connecting hole 15a Inner surface (spherical seat)
16 Connection board 16a Female screw hole 17 Rotating tool 18 Concrete slab 20 Supporting leg 21 Channel 22 Groove (channel)
A Conventional nuclear fuel storage rack B Nuclear fuel storage rack C Nuclear fuel storage rack O1 Axis W Water

Claims (9)

A nuclear fuel storage rack installed in the water in the storage pit with the nuclear fuel assembly stored therein,
A cell storage unit that stores and holds a plurality of rack cells that contain the nuclear fuel assemblies, and a plurality of support legs that are connected to the cell storage unit and support the cell storage unit,
The support leg is provided so as to be connected to a leg projecting downward from the cell storage and a lower end of the leg, and is grounded to the bottom surface of the storage pit to support the cell storage Shaped pedestal,
A nuclear fuel storage rack, wherein the pedestal portion is movably connected to the leg portion. The nuclear fuel storage rack according to claim 1,
The support leg is provided with a connecting member that connects the pedestal part to the leg part by arranging the axial direction in the vertical direction, connecting the upper end side to the leg part, connecting the lower end side to the pedestal part,
The connection member is formed with a spherical portion on at least one of the upper end side and the lower end side, and at least one of the pedestal portion and the leg portion has a connection hole having a concave spherical surface on the inner surface. Is formed,
A nuclear fuel storage rack, wherein the spherical portion is slidably engaged with a spherical seat of the connecting hole, and the pedestal portion is movably connected to the leg portion. The nuclear fuel storage rack according to claim 2,
The connecting member includes the spherical portion on the lower end side and a rod-shaped male screw portion formed on the outer peripheral surface by threading a male screw on the upper end side, and is open on the upper end surface. And formed with a rotary tool mounting hole drilled in the center of the axis,
The leg portion is formed with a connecting board having a female screw hole drilled at the lower end,
The connecting member can be moved forward and backward in the vertical direction by screwing the male screw portion into the female screw hole of the connecting plate, attaching a rotary tool to the rotary tool mounting hole, and rotating forward and backward around an axis. A nuclear fuel storage rack connected to a leg. The nuclear fuel storage rack according to any one of claims 1 to 3,
The nuclear fuel storage rack, wherein the support leg is configured to include an elastic body between a lower end surface of the leg portion and an upper end surface of the pedestal portion. The nuclear fuel storage rack according to any one of claims 1 to 4,
The bottom of the storage pit is formed with a concrete slab;
When the pedestal is brought into contact with the bottom surface of the storage pit, the area of the ground contact surface that is grounded to the bottom surface of the storage pit rises from the bottom surface of the storage pit when rocking occurs in the nuclear fuel storage rack. A nuclear fuel storage rack, which is set and formed based on a load acting on the concrete slab. The nuclear fuel storage rack according to any one of claims 1 to 5,
The connection hole is provided with the spherical seat at the bottom and extends in the vertical direction, and the spherical portion engaged with the connection hole is formed to be movable in the vertical direction.
The nuclear fuel is characterized in that at least one of the pedestal part and the leg part in which the connection hole is formed has a flow path through which water flows through the connection hole and the outside. Storage rack. The nuclear fuel storage rack according to claim 6,
A nuclear fuel storage rack, wherein a groove serving as a flow path through which water in the connection hole flows is formed on an outer peripheral surface of the spherical body. The nuclear fuel storage rack according to claim 6 or 7,
The nuclear fuel storage rack according to claim 1, wherein a channel for communicating the connection hole with the outside is formed to open to a grounding surface of the pedestal portion grounded to a bottom surface of the storage pit. The nuclear fuel storage rack according to any one of claims 1 to 5,
The connection hole is provided with the spherical seat at the bottom and extends in the vertical direction, and the spherical portion engaged with the connection hole is formed to be movable in the vertical direction.
A nuclear fuel storage rack, wherein a viscoelastic body is disposed in the connection hole.

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