JP6783199B2 - Nuclear fuel storage rack - Google Patents

Description

The present invention relates to a nuclear fuel storage rack that supports the nuclear fuel in order to store the nuclear fuel in a standing state in water in a storage pit.

For example, in Patent Document 1, a nuclear fuel storage rack is slidably mounted on the floor (bottom surface) of a storage pit, and the horizontal force acting at the time of an earthquake is applied to the nuclear fuel storage rack together with the fluid resistance of water. A so-called free standing rack that absorbs by sliding resistance is shown.

Japanese Unexamined Patent Publication No. 2011-220869

The free-standing nuclear fuel storage rack as described in Patent Document 1 described above has high seismic resistance, but the amount of slippage increases as the seismic level increases, avoiding collision or approach to the vertical wall surface of the storage pit. Therefore, it was necessary to increase the distance from the vertical wall surface in consideration of the amount of slippage. Therefore, there is a problem that the storage space for nuclear fuel becomes narrower toward the inside of the storage pit and the number of nuclear fuel storage bodies in the storage pit decreases. Further, in order to secure the number of nuclear fuel storage bodies in the storage pit, there is a problem that the size of the storage pit becomes large.

The present invention solves the above-mentioned problems, and an object of the present invention is to provide a nuclear fuel storage rack capable of preventing collision or approach to a vertical wall surface of a storage pit.

In order to achieve the above object, the nuclear fuel storage rack according to one aspect of the present invention is a nuclear fuel storage rack that is arranged on the floor surface at a distance from the vertical wall surface in the water in the storage pit. A support structure formed so as to cause locking toward the nearest vertical wall surface side is provided.

Further, in the nuclear fuel storage rack according to one aspect of the present invention, it is preferable that the support structure shifts the position of the center of gravity of the rack body toward the nearest vertical wall surface.

Further, in the nuclear fuel storage rack according to one aspect of the present invention, it is preferable that the support structure displaces the position of the center of gravity of the rack body closer to the nearest vertical wall surface by making the weight distribution in the rack body asymmetric.

Further, in the nuclear fuel storage rack according to one aspect of the present invention, the support structure greatly displaces the weight distribution of the rack body as it approaches the nearest vertical wall surface, so that the center of gravity of the rack body approaches the closest vertical wall surface. It is preferable to displace the position.

Further, in the nuclear fuel storage rack according to one aspect of the present invention, the support structure may displace the position of the center of gravity of the rack body closer to the nearest vertical wall surface by attaching a weight to the lower side of the base plate of the rack body. preferable.

Further, in the nuclear fuel storage rack according to one aspect of the present invention, the support structure has a center of gravity of the rack body closer to the vertical wall surface closest to the vertical wall surface by increasing the weight of the outer peripheral plate of the rack body. It is preferable to displace the position.

Further, in the nuclear fuel storage rack according to one aspect of the present invention, it is preferable that the support structure is formed so that the coefficient of friction with the floor surface increases as it approaches the nearest vertical wall surface.

Further, in the nuclear fuel storage rack according to one aspect of the present invention, the support structure includes a plurality of support legs provided on the bottom surface of the rack body, and the area of the leg surface portion of the support legs in contact with the floor surface is increased. It is preferable that the vertical wall surface is formed so that the coefficient of friction with the floor surface increases as it approaches the nearest vertical wall surface.

Further, in the nuclear fuel storage rack according to one aspect of the present invention, it is preferable that the support structure is displaced so that the center of rotation that locks toward the closest vertical wall surface side is closer to the center of gravity of the rack body.

Further, in the nuclear fuel storage rack according to one aspect of the present invention, the support structure includes a plurality of support legs provided on the bottom surface of the rack body, and the support legs are arranged so as to be asymmetrical with the bottom surface of the rack body. It is preferable to displace the center of rotation that locks toward the vertical wall surface side closest to the rack body so as to be closer to the center of gravity of the rack body.

Further, in the nuclear fuel storage rack according to one aspect of the present invention, the support structure includes a plurality of support legs provided on the bottom surface of the rack body, and the leg surface portion of the support legs in contact with the floor surface is closest to the support legs. It is preferable to displace the rotation center that locks toward the vertical wall surface side that is closest to the vertical wall surface side by being supported by the spherical seat so as to be closer to the center of gravity of the rack body.

The nuclear fuel storage rack of the present invention slides horizontally along the floor surface of the storage pit when a horizontal force is applied at the time of an earthquake. At this time, according to the nuclear fuel storage rack of the present invention, since it has a support structure that causes locking toward the nearest vertical wall surface side, when a horizontal force acts in the direction approaching the nearest vertical wall surface side, Locking that rotates so that the upper part tilts in that direction (closest vertical wall side) is likely to occur, while locking is less likely to occur when a horizontal force acts in the direction away from the nearest vertical wall side. .. Therefore, the nuclear fuel storage rack includes a recoil of locking toward the nearest vertical wall surface side and moves in a direction away from the nearest vertical wall surface side. As a result, it is possible to prevent the storage pit from colliding with or approaching the vertical wall surface. Since it is not necessary to place the nuclear fuel far from the vertical wall surface, the number of nuclear fuel storage bodies in the storage pit can be secured, and the storage pit can be prevented from becoming large and the size of the storage pit can be reduced. can do.

FIG. 1 is a side sectional view of the storage pit. FIG. 2 is a plan view of the storage pit. FIG. 3 is a side view showing a support structure in the nuclear fuel storage rack according to the first embodiment of the present invention. FIG. 4 is a side view showing the operation of the nuclear fuel storage rack according to the first embodiment of the present invention. FIG. 5 is a plan view showing a support structure in the nuclear fuel storage rack according to the first embodiment of the present invention. FIG. 6 is a side view showing a support structure in the nuclear fuel storage rack according to the second embodiment of the present invention. FIG. 7 is a side view showing the operation of the nuclear fuel storage rack according to the second embodiment of the present invention. FIG. 8 is a plan view showing a support structure in the nuclear fuel storage rack according to the second embodiment of the present invention. FIG. 9 is a side view showing a support structure in the nuclear fuel storage rack according to the third embodiment of the present invention. FIG. 10 is a side view showing the operation of the nuclear fuel storage rack according to the third embodiment of the present invention. FIG. 11 is a plan view showing a support structure in the nuclear fuel storage rack according to the third embodiment of the present invention. FIG. 12 is a side view showing a support structure in the nuclear fuel storage rack according to the fourth embodiment of the present invention. FIG. 13 is a side view showing the operation of the nuclear fuel storage rack according to the fourth embodiment of the present invention. FIG. 14 is a plan view showing a support structure in the nuclear fuel storage rack according to the fourth embodiment of the present invention.

Hereinafter, embodiments according to the present invention will be described in detail with reference to the drawings. The present invention is not limited to this embodiment. In addition, the components in the following embodiments include those that can be easily replaced by those skilled in the art, or those that are substantially the same.

FIG. 1 is a side sectional view of the storage pit. FIG. 2 is a plan view of the storage pit.

The storage pit 101 stores used fuel assemblies used in the nuclear reactor in a nuclear power plant and unused fuel assemblies. A fuel assembly is an assembly in which nuclear fuel, which is a plurality of fuel rods, is bundled. Therefore, the fuel assembly is a so-called nuclear fuel. The storage pit 101 is configured as a pool of a rectangular skeleton with an open top. The storage pit 101 has a floor surface 101a and a vertical wall surface 101b of a peripheral side wall. In the storage pit 101, the nuclear fuel storage rack 1 is arranged on the floor surface 101a. The nuclear fuel storage rack 1 is provided with a plurality of fuel storage portions 1a having an open upper portion and partitioned in a grid pattern. Then, the storage pit 101 is stored and stored in a state where the water W is stored inside, and the fuel assembly is erected in each fuel storage unit 1a of the nuclear fuel storage rack 1.

The storage pit 101 has a lining attached to the concrete surface which is the inner surface of the floor surface 101a and the vertical wall surface 101b. The lining is made of austenitic stainless steel having a thickness of about 6 mm, and protects the inner surfaces of the floor surface 101a and the vertical wall surface 101b of the storage pit 101.

The nuclear fuel storage rack 1 is provided with support legs 1c on the bottom surface of the rack main body 1b having each fuel storage portion 1a, and the rack main body 1b is independently supported on the floor surface 101a by the support legs 1c. The support legs 1c are so-called free-standing racks that are provided so as to be slidable with respect to the floor surface 101a so that they can move relative to the floor surface 101a. A plurality of nuclear fuel storage racks 1 are placed on the floor surface 101a with the rack body 1b having a rectangular parallelepiped outer shape and a distance L from the four vertical wall surfaces 101b surrounding the storage pit 101 in a rectangular shape. In FIG. 2, 12) are arranged in a rectangular shape. Further, in each nuclear fuel storage rack 1, rack bodies 1b of each other are provided at predetermined intervals.

By the way, the free-standing nuclear fuel storage rack 1 has high seismic resistance by absorbing the horizontal force acting at the time of an earthquake by the sliding resistance of the nuclear fuel storage rack 1 together with the fluid resistance of water. On the other hand, as the earthquake level increases, the amount of slippage increases, so that the collision or approach of the storage pit 101 with the vertical wall surface 101b has become an issue. When the nuclear fuel storage rack 1 collides with the vertical wall surface 101b of the storage pit 101, the lining of the vertical wall surface 101b is damaged and the vertical wall surface 101b cannot be protected. Further, when the nuclear fuel storage rack 1 approaches the vertical wall surface 101b of the storage pit 101, the nuclear fuel may be close to a passage or the like existing on the other side of the wall of the storage pit 101, and the influence of radiation may occur. On the other hand, in order to avoid collision or approach of the storage pit 101 to the vertical wall surface 101b, if the distance L from the vertical wall surface 101b to the rack body 1b is increased in consideration of the amount of sliding of the nuclear fuel storage rack 1, the nuclear fuel is stored. Since the space becomes narrower toward the inside of the storage pit 101, there arises a problem that the number of nuclear fuel storage bodies in the storage pit 101 is reduced. In each of the following embodiments, a nuclear fuel storage rack 1 for solving this problem is provided.

[Embodiment 1]
FIG. 3 is a side view showing a support structure in the nuclear fuel storage rack according to the first embodiment. FIG. 4 is a side view showing the operation of the nuclear fuel storage rack according to the first embodiment. FIG. 5 is a plan view showing a support structure in the nuclear fuel storage rack according to the first embodiment.

The nuclear fuel storage rack 1 of the present embodiment includes a support structure that causes locking toward the nearest vertical wall surface 101b. Here, the “closest vertical wall surface 101b side” refers to the nuclear fuel storage rack 1 arranged on the floor surface 101a of the storage pit 101 with respect to the vertical wall surface 101b on which the side surface of the rack body 1b faces, as described above. It means that the distance is the shortest side. When the nuclear fuel storage rack 1 is arranged so that the corners formed by the two side surfaces of the rack body 1b are oriented with respect to the corners formed by the two vertical wall surfaces 101b in the storage pit 101, the two side surfaces are provided. The side facing each vertical wall surface 101b and the corner side formed by each vertical wall surface 101b is referred to as the "closest vertical wall surface 101b side".

Specifically, in the support structure, the center of gravity G of the nuclear fuel storage rack 1 (rack body 1b) is displaced toward the nearest vertical wall surface 101b. 3 to 5 show a form in which the center of gravity G is displaced to a region where the color is darkened near the nearest vertical wall surface 101b. The position where the center of gravity G is displaced is closer to the vertical wall surface 101b, which is closest to the center (center) of the nuclear fuel storage rack 1. The support structure is configured so that, for example, the weight distribution in the rack body 1b is asymmetrical so that the position of the center of gravity of the rack body 1b is displaced toward the nearest vertical wall surface 101b. Further, the support structure is configured so that, for example, the weight distribution of the rack body is largely displaced as it approaches the nearest vertical wall surface. The displacement of the center of gravity G due to the support structure can be realized, for example, by collecting the fuel assemblies near the nearest vertical wall surface 101b in the nuclear fuel storage rack 1 and storing them in the fuel storage unit 1a. Further, for the displacement of the center of gravity G due to the support structure, for example, in the nuclear fuel storage rack 1 before the fuel assembly is stored, the dummy fuel assembly is collected near the nearest vertical wall surface 101b and stored in the fuel storage unit 1a. It can be realized by. Further, the displacement of the center of gravity G due to the support structure is determined by, for example, making the plate material (outer peripheral plate) constituting the periphery of the rack body 1b in the nuclear fuel storage rack 1 thicker or heavier toward the nearest vertical wall surface 101b. This can be achieved by increasing the weight of the plate material by using it. Further, the displacement of the center of gravity G due to the support structure can be realized, for example, by attaching a weight to the nearest vertical wall surface 101b below the bottom portion (base plate) of the rack body 1b in the nuclear fuel storage rack 1.

Then, the nuclear fuel storage rack 1 slides in the horizontal direction along the floor surface 101a when a horizontal force acts at the time of an earthquake. At this time, since the nuclear fuel storage rack 1 of the present embodiment has a support structure that causes locking toward the closest vertical wall surface 101b, as shown by a solid line in FIG. 4, the closest vertical wall surface When a horizontal force acts in the direction approaching the 101b side, the center of gravity G is displaced toward the nearest vertical wall surface 101b, so that the upper part of the rack body 1b is tilted in that direction (closest vertical wall surface 101b side). Rotating locking is likely to occur, while locking is less likely to occur when a horizontal force acts in the direction away from the nearest vertical wall surface 101b side, as shown by the alternate long and short dash line in FIG. Therefore, the nuclear fuel storage rack 1 includes a recoil of locking toward the nearest vertical wall surface 101b side, and moves in a direction away from the nearest vertical wall surface 101b side. As a result, it is possible to prevent the storage pit 101 from colliding with or approaching the vertical wall surface 101b. Since it is not necessary to arrange the nuclear fuel far from the vertical wall surface, it is possible to secure the number of nuclear fuel storage bodies in the storage pit 101, and prevent the storage pit 101 from becoming large, so that the storage pit 101 The size can be reduced.

Further, in the nuclear fuel storage rack 1 of the present embodiment, as described above, the rack body 1b has a rectangular parallelepiped outer shape, and the distance L is separated from the four vertical wall surfaces 101b that surround the storage pit 101 in a rectangular shape. In this state, a plurality (12 in FIG. 2) are arranged and arranged on the floor surface 101a. Therefore, as shown in FIG. 5, the displacement of the center of gravity G, which is the support structure, is determined in the nuclear fuel storage rack 11 in which the corners of the rack body 1b face the corners formed by the vertical wall surfaces 101b on the two surfaces of the storage pit 101. The center of gravity G is displaced toward the corner portion formed by each vertical wall surface 101b, which is closer to the nearest vertical wall surface 101b. Then, in the nuclear fuel storage rack 12 in which one surface of the rack body 1b faces the vertical wall surface 101b on one surface of the storage pit 101, the center of gravity G is displaced toward the closest vertical wall surface 101b. Further, in the central nuclear fuel storage rack 13 surrounded by the nuclear fuel storage rack 11 and the nuclear fuel storage rack 12 without facing the vertical wall surface 101b, the center of gravity G, which is the support structure, is not displaced. By doing so, the nuclear fuel storage rack 11 and the nuclear fuel storage rack 12 are oriented away from the nearest vertical wall surface 101b side toward the center of the storage pit 101 (central nuclear fuel storage rack 13). It will move. As a result, it is possible to prevent the storage pit 101 from colliding with or approaching the vertical wall surface 101b, to secure the number of nuclear fuel stores in the storage pit 101, and to prevent the storage pit 101 from becoming large for storage. The size of the pit 101 can be reduced.

Regarding the event that the nuclear fuel storage racks 11, 12 and 13 collide with each other, the strength of the nuclear fuel storage racks 11, 12 and 13 may be increased, or a damper or the like may be buffered between the nuclear fuel storage racks 11, 12 and 13. By interposing a member, the nuclear fuel storage racks 11, 12, and 13 are prevented from being damaged by the collision.

[Embodiment 2]
FIG. 6 is a side view showing a support structure in the nuclear fuel storage rack according to the second embodiment. FIG. 7 is a side view showing the operation of the nuclear fuel storage rack according to the second embodiment. FIG. 8 is a plan view showing a support structure in the nuclear fuel storage rack according to the second embodiment.

The nuclear fuel storage rack 1 of the present embodiment includes a support structure that causes locking toward the nearest vertical wall surface 101b. The definition of "closest vertical wall surface 101b side" is the same as that described in the first embodiment. Specifically, in the support structure, the coefficient of friction between the leg surface portion in contact with the floor surface 101a of the support leg 1c and the floor surface 101a increases as the support leg 1c of the nuclear fuel storage rack 1 approaches the nearest vertical wall surface 101b. It is composed of. The support structure is configured so that, for example, the area of the leg surface portion increases as it approaches the nearest vertical wall surface. 6 to 8 show a form in which the friction coefficient of the support leg 1c having a darker color near the nearest vertical wall surface 101b is larger than that of the support leg 1c having no color. The coefficient of friction can be increased, for example, by changing the material and surface roughness of the entire support leg 1c or the portion of the support leg 1c in contact with the floor surface 101a.

Then, the nuclear fuel storage rack 1 slides in the horizontal direction along the floor surface 101a when a horizontal force acts at the time of an earthquake. At this time, since the nuclear fuel storage rack 1 of the present embodiment has a support structure that causes locking toward the closest vertical wall surface 101b side, as shown by the solid line in FIG. 7, the closest vertical wall surface When a horizontal force acts in the direction approaching the 101b side, the coefficient of friction with the floor surface 101a is increased toward the nearest vertical wall surface 101b, so that the rack body 1b is located in that direction (closest vertical wall surface 101b side). Locking that rotates so that the upper part tilts is likely to occur, while locking is unlikely to occur when a horizontal force acts in the direction away from the nearest vertical wall surface 101b side, as shown by the alternate long and short dash line in FIG. Become. Therefore, the nuclear fuel storage rack 1 includes a recoil of locking toward the nearest vertical wall surface 101b side, and moves in a direction away from the nearest vertical wall surface 101b side. As a result, it is possible to prevent the storage pit 101 from colliding with or approaching the vertical wall surface 101b. Since it is not necessary to arrange the nuclear fuel far from the vertical wall surface, it is possible to secure the number of nuclear fuel storage bodies in the storage pit 101, and prevent the storage pit 101 from becoming large, so that the storage pit 101 The size can be reduced.

Further, in the nuclear fuel storage rack 1 of the present embodiment, as described above, the rack body 1b has a rectangular parallelepiped outer shape, and the distance L is separated from the four vertical wall surfaces 101b that surround the storage pit 101 in a rectangular shape. In this state, a plurality of (12 in FIG. 2) are arranged and arranged on the floor surface 101a. Therefore, as shown in FIG. 8, the coefficient of friction, which is the support structure, is the highest in the nuclear fuel storage rack 11 in which the corners of the rack body 1b face the corners formed by the vertical wall surfaces 101b on the two surfaces of the storage pit 101. The coefficient of friction with the floor surface 101a is increased closer to each vertical wall surface 101b and closer to the corner formed by each vertical wall surface 101b. Then, in the nuclear fuel storage rack 12 in which one surface of the rack body 1b faces the vertical wall surface 101b on one surface of the storage pit 101, the coefficient of friction with the floor surface 101a is increased toward the nearest vertical wall surface 101b. Further, in the central nuclear fuel storage rack 13 which is surrounded by the nuclear fuel storage rack 11 and the nuclear fuel storage rack 12 without facing the vertical wall surface 101b, the friction coefficient, which is the support structure, is not changed. By doing so, the nuclear fuel storage rack 11 and the nuclear fuel storage rack 12 are oriented away from the nearest vertical wall surface 101b side toward the center of the storage pit 101 (central nuclear fuel storage rack 13). It will move. As a result, it is possible to prevent the storage pit 101 from colliding with or approaching the vertical wall surface 101b, to secure the number of nuclear fuel stores in the storage pit 101, and to prevent the storage pit 101 from becoming large for storage. The size of the pit 101 can be reduced. In FIG. 8, the support legs 1c are provided at four corners on the bottom surface of the rectangular parallelepiped rack body 1b, but the number of support legs 1c is such that the rack body 1b is stable and independent on the floor surface 101a. It is not limited as long as it can be done.

Regarding the event that the nuclear fuel storage racks 11, 12 and 13 collide with each other, the strength of the nuclear fuel storage racks 11, 12 and 13 may be increased, or a damper or the like may be buffered between the nuclear fuel storage racks 11, 12 and 13. By interposing a member, the nuclear fuel storage racks 11, 12, and 13 are prevented from being damaged by the collision.

[Embodiment 3]
FIG. 9 is a side view showing a support structure in the nuclear fuel storage rack according to the third embodiment. FIG. 10 is a side view showing the operation of the nuclear fuel storage rack according to the third embodiment. FIG. 11 is a plan view showing a support structure in the nuclear fuel storage rack according to the third embodiment.

The nuclear fuel storage rack 1 of the present embodiment includes a support structure that causes locking toward the nearest vertical wall surface 101b. The definition of "closest vertical wall surface 101b side" is the same as that described in the first embodiment. Specifically, in the support structure, the rotation center C that locks toward the nearest vertical wall surface 101b is displaced so as to approach the center of gravity G of the nuclear fuel storage rack 1 (rack body 1b). As shown in FIGS. 9 to 11, for example, the displacement of the locking rotation center C due to the support structure is closer to the nearest vertical wall surface 101b with respect to the support legs 1c of the nuclear fuel storage rack 1 (to the closest vertical wall surface 101b side). Rotation that locks toward the nearest vertical wall surface 101b by arranging the support legs 1c) located under the side surface of the rack body 1b facing away from the vertical wall surface 101b in an asymmetrical arrangement on the bottom surface of the rack body 1b. It is possible to realize that the center C is displaced so as to be closer to the center of gravity G of the nuclear fuel storage rack 1. When the support legs 1c are arranged symmetrically on the bottom surface of the rack body 1b, the center of rotation of the locking is evenly located at the outer end of each support leg 1c. 9 to 11 show a form in which the support legs 1c having a darker color closer to the nearest vertical wall surface 101b are arranged away from the vertical wall surface 101b.

Then, the nuclear fuel storage rack 1 slides in the horizontal direction along the floor surface 101a when a horizontal force acts at the time of an earthquake. At this time, since the nuclear fuel storage rack 1 of the present embodiment has a support structure that causes locking toward the closest vertical wall surface 101b, as shown by the solid line in FIG. 10, the closest vertical wall surface When a horizontal force acts in the direction approaching the 101b side, the rotation center C that locks toward the nearest vertical wall surface 101b side is displaced so as to approach the center of gravity G of the nuclear fuel storage rack 1. Locking that rotates so that the upper part of the rack body 1b is tilted toward the nearest vertical wall surface 101b side) is likely to occur, while horizontal as shown by the alternate long and short dash line in FIG. 10 in the direction away from the nearest vertical wall surface 101b side. When a force is applied, locking is less likely to occur. Therefore, the nuclear fuel storage rack 1 includes a recoil of locking toward the nearest vertical wall surface 101b side, and moves in a direction away from the nearest vertical wall surface 101b side. As a result, it is possible to prevent the storage pit 101 from colliding with or approaching the vertical wall surface 101b. Since it is not necessary to arrange the nuclear fuel far from the vertical wall surface, it is possible to secure the number of nuclear fuel storage bodies in the storage pit 101, and prevent the storage pit 101 from becoming large, so that the storage pit 101 The size can be reduced.

Further, in the nuclear fuel storage rack 1 of the present embodiment, as described above, the rack body 1b has a rectangular parallelepiped outer shape, and the distance L is separated from the four vertical wall surfaces 101b that surround the storage pit 101 in a rectangular shape. In this state, a plurality (12 in FIG. 2) are arranged and arranged on the floor surface 101a. Therefore, as shown in FIG. 11, the displacement of the rotation center C, which is the support structure, is the nuclear fuel storage rack 11 in which the corners of the rack body 1b face the corners formed by the vertical wall surfaces 101b on the two surfaces of the storage pit 101. Is a nuclear fuel storage center of rotation C that locks the support legs 1c that are closer to each vertical wall surface 101b and closer to the corners formed by each vertical wall surface 101b toward the nearest vertical wall surface 101b away from the corners. Displace it so that it approaches the center of gravity G of the rack 1. Then, in the nuclear fuel storage rack 12 in which one surface of the rack body 1b faces the vertical wall surface 101b on one surface of the storage pit 101, the support legs 1c closer to the vertical wall surface 101b are moved away from the vertical wall surface 101b and are closest to each other. The rotation center C that locks toward the vertical wall surface 101b is displaced so as to approach the center of gravity G of the nuclear fuel storage rack 1. Further, in the central nuclear fuel storage rack 13 which is surrounded by the nuclear fuel storage rack 11 and the nuclear fuel storage rack 12 without facing the vertical wall surface 101b, the rotation center C, which is a support structure, is not displaced. By doing so, the nuclear fuel storage rack 11 and the nuclear fuel storage rack 12 are oriented away from the nearest vertical wall surface 101b side toward the center of the storage pit 101 (central nuclear fuel storage rack 13). It will move. As a result, it is possible to prevent the storage pit 101 from colliding with or approaching the vertical wall surface 101b, to secure the number of nuclear fuel stores in the storage pit 101, and to prevent the storage pit 101 from becoming large for storage. The size of the pit 101 can be reduced. In FIG. 11, the support legs 1c are provided at four corners and four sides of the bottom surface of the rectangular parallelepiped rack body 1b, for a total of eight positions. However, the number of support legs 1c is determined by the rack body 1b. It is not limited as long as it can stably stand on the floor surface 101a.

Regarding the event that the nuclear fuel storage racks 11, 12 and 13 collide with each other, the strength of the nuclear fuel storage racks 11, 12 and 13 may be increased, or a damper or the like may be buffered between the nuclear fuel storage racks 11, 12 and 13. By interposing a member, the nuclear fuel storage racks 11, 12, and 13 are prevented from being damaged by the collision.

[Embodiment 4]
FIG. 12 is a side view showing a support structure in the nuclear fuel storage rack according to the fourth embodiment. FIG. 13 is a side view showing the operation of the nuclear fuel storage rack according to the fourth embodiment. FIG. 14 is a plan view showing a support structure in the nuclear fuel storage rack according to the fourth embodiment.

The nuclear fuel storage rack 1 of the present embodiment includes a support structure that causes locking toward the nearest vertical wall surface 101b. The definition of "closest vertical wall surface 101b side" is the same as that described in the first embodiment. Specifically, in the support structure, the rotation center C that locks toward the nearest vertical wall surface 101b is displaced so as to approach the center of gravity G of the nuclear fuel storage rack 1. As shown in FIGS. 12 to 14, the displacement of the locking rotation center C due to the support structure is, for example, the one closer to the nearest vertical wall surface 101b with respect to the support leg 1c of the nuclear fuel storage rack 1 (to the closest vertical wall surface 101b side). The support leg 1c) located below the side surface of the rack body 1b facing the rack body 1c) is configured to swingably support the leg surface portion 1cc in contact with the floor surface 101a with the spherical seat 1ca, and the spherical seat 1ca is provided for the other support legs 1c. By enlarging the leg surface portion 1cc without using it, the rotation center C (corresponding to the swing support portion of the spherical seat 1ca) that locks toward the nearest vertical wall surface 101b side becomes the center of gravity G of the nuclear fuel storage rack 1. It is possible to realize the displacement so as to approach each other. When the support legs 1c are arranged symmetrically on the bottom surface of the rack body 1b, the center of rotation of the locking is evenly located at the outer end of each support leg 1c. Regarding the other support legs 1c, even if the leg surface portion 1cc is not enlarged and the spherical seat 1ca is not used, the rotation center C (the swing support portion of the spherical seat 1ca) that locks toward the nearest vertical wall surface 101b side can be used. It can be realized that the equivalent) is displaced so as to approach the center of gravity G of the nuclear fuel storage rack 1. 12 to 14 show a form in which the leg surface portion 1cc is enlarged without using the spherical seat 1ca for the support leg 1c having a darker color near the nearest vertical wall surface 101b.

Then, the nuclear fuel storage rack 1 slides in the horizontal direction along the floor surface 101a when a horizontal force acts at the time of an earthquake. At this time, since the nuclear fuel storage rack 1 of the present embodiment has a support structure that causes locking toward the closest vertical wall surface 101b, as shown by the solid line in FIG. 13, the closest vertical wall surface When a horizontal force acts in the direction approaching the 101b side, the rotation center C that locks toward the nearest vertical wall surface 101b side is displaced so as to approach the center of gravity G of the nuclear fuel storage rack 1, so that direction (most). Locking that rotates so that the upper part of the rack body 1b is tilted on the nearest vertical wall surface 101b side) is likely to occur, while horizontal force is generated in the direction away from the nearest vertical wall surface 101b side as shown by the alternate long and short dash line in FIG. When is acting, locking is less likely to occur. Therefore, the nuclear fuel storage rack 1 includes a recoil of locking toward the nearest vertical wall surface 101b side, and moves in a direction away from the nearest vertical wall surface 101b side. As a result, it is possible to prevent the storage pit 101 from colliding with or approaching the vertical wall surface 101b. Since it is not necessary to arrange the nuclear fuel far from the vertical wall surface, it is possible to secure the number of nuclear fuel storage bodies in the storage pit 101, and prevent the storage pit 101 from becoming large, so that the storage pit 101 The size can be reduced.

Further, in the nuclear fuel storage rack 1 of the present embodiment, as described above, the rack body 1b has a rectangular parallelepiped outer shape, and the distance L is separated from the four vertical wall surfaces 101b that surround the storage pit 101 in a rectangular shape. In this state, a plurality of (12 in FIG. 2) are arranged and arranged on the floor surface 101a. Therefore, as shown in FIG. 14, the displacement of the rotation center C, which is the support structure, is determined in the nuclear fuel storage rack 11 in which the corners of the rack body 1b face the corners formed by the vertical wall surfaces 101b on the two surfaces of the storage pit 101. Uses a spherical seat 1ca on the support legs 1c near the vertical wall surfaces 101b forming the corners (support legs 1c located below the side surfaces of the rack body 1b facing the vertical wall surfaces 101b forming the corners). The rotation center C that locks toward the nearest vertical wall surface 101b is displaced so as to be closer to the center of gravity G of the nuclear fuel storage rack 1. Then, in the nuclear fuel storage rack 12 in which one side of the rack body 1b faces the vertical wall surface 101b on one side of the storage pit 101, the support legs 1c (the rack facing the closest vertical wall surface 101b side) closer to the nearest vertical wall surface 101b side. A spherical seat 1ca is used on the support leg 1c) located below the side surface of the main body 1b, and the rotation center C that locks toward the nearest vertical wall surface 101b is displaced so as to approach the center of gravity G of the nuclear fuel storage rack 1. .. Further, in the central nuclear fuel storage rack 13 which is surrounded by the nuclear fuel storage rack 11 and the nuclear fuel storage rack 12 without facing the vertical wall surface 101b, the rotation center C, which is a support structure, is not displaced. By doing so, the nuclear fuel storage rack 11 and the nuclear fuel storage rack 12 are oriented away from the nearest vertical wall surface 101b side toward the center of the storage pit 101 (central nuclear fuel storage rack 13). It will move. As a result, it is possible to prevent the storage pit 101 from colliding with or approaching the vertical wall surface 101b, to secure the number of nuclear fuel stores in the storage pit 101, and to prevent the storage pit 101 from becoming large for storage. The size of the pit 101 can be reduced. In FIG. 14, the support legs 1c are provided at four corners and four sides of the bottom surface of the rectangular parallelepiped rack body 1b, for a total of eight positions. However, the number of support legs 1c is determined by the rack body 1b. It is not limited as long as it can stably stand on the floor surface 101a.

Regarding the event that the nuclear fuel storage racks 11, 12 and 13 collide with each other, the strength of the nuclear fuel storage racks 11, 12 and 13 may be increased, or a damper or the like may be buffered between the nuclear fuel storage racks 11, 12 and 13. By interposing a member, the nuclear fuel storage racks 11, 12, and 13 are prevented from being damaged by the collision.

It should be noted that at least two of the above-described first to fourth embodiments can be combined as appropriate.

1 (11, 12, 13) Nuclear fuel storage rack 1a Fuel storage 1b Rack body 1c Support leg 1ca Spherical seat 1cc Leg surface 101 Storage pit 101a Floor surface 101b Vertical wall surface C Rotation center G Center of gravity L Distance W Water

Claims (11)

A nuclear fuel storage rack that is placed on the floor at a distance from the vertical wall surface in the water in the storage pit.
A nuclear fuel storage rack having a support structure formed so as to cause locking toward the nearest vertical wall surface side. The nuclear fuel storage rack according to claim 1, wherein the support structure displaces the position of the center of gravity of the rack body closer to the vertical wall surface closest to the rack. The nuclear fuel storage rack according to claim 2, wherein the support structure displaces the position of the center of gravity of the rack body closer to the vertical wall surface closest to the rack body by making the weight distribution asymmetric. The nuclear fuel storage according to claim 2 or 3, wherein the support structure largely displaces the weight distribution of the rack body toward the nearest vertical wall surface to displace the position of the center of gravity of the rack body toward the nearest vertical wall surface. Rack for. The nuclear fuel storage rack according to claim 3 or 4, wherein the support structure is such that the position of the center of gravity of the rack body is displaced toward the nearest vertical wall surface by attaching a weight to the lower side of the base plate of the rack body. The nuclear fuel storage according to claim 3 or 4, wherein the support structure shifts the position of the center of gravity of the rack body closer to the vertical wall surface by increasing the weight of the outer peripheral plate of the rack body closer to the vertical wall surface. Rack for. The nuclear fuel storage rack according to any one of claims 1 to 6, wherein the support structure is formed so that the coefficient of friction with the floor surface increases as it approaches the nearest vertical wall surface. The support structure includes a plurality of support legs provided on the bottom surface of the rack body.
The nuclear fuel according to claim 7, wherein the area of the leg surface portion of the support leg in contact with the floor surface increases as it approaches the nearest vertical wall surface, so that the coefficient of friction with the floor surface increases. Storage rack. The nuclear fuel storage rack according to any one of claims 1 to 8, wherein the support structure is displaced so that the center of rotation that locks toward the nearest vertical wall surface side is brought closer to the center of gravity of the rack body. The support structure includes a plurality of support legs provided on the bottom surface of the rack body.
The ninth aspect of claim 9, wherein the support legs are arranged so as to be asymmetrical on the bottom surface of the rack body so that the center of rotation that locks toward the nearest vertical wall surface side is displaced so as to approach the center of gravity of the rack body. Nuclear fuel storage rack. The support structure includes a plurality of support legs provided on the bottom surface of the rack body.
The leg surface portion of the support leg in contact with the floor surface is supported by the spherical seat on the closest vertical wall surface side, so that the rotation center that locks toward the nearest vertical wall surface side is brought closer to the center of gravity of the rack body. The nuclear fuel storage rack according to claim 9, which is displaced in such a manner.

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