JP2013186015A - Fuel storage rack - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel storage rack capable of suppressing occurrence of rocking and stabilizing behavior in the case of earthquake.SOLUTION: Provided is a fuel storage rack which includes: a rack main body section comprising a base plate 11 and a rack storage section 12, which store a large number of rack cells 2 in which a fuel assembly is housed; and a plurality of rack legs 13 supporting the rack main body section, and is aligned in a storage pit, in which the rack legs 13 support the rack main body section in a slidable manner with respect to a floor surface of the storage pit. The rack is provided with fins 14 each of which includes: a vertical plate 14a which vertically hangs down from the bottom surface of the rack main body section along a lengthwise direction of the rack main body section and whose length in a vertical direction is set shorter than the rack leg 13; a horizontal plate 14b extending from the bottom end of the vertical plate 14a in a width direction of the rack main body section; and a through hole 14c formed in the horizontal plate 14b.

Description

  The present invention relates to a fuel storage rack that houses a fuel assembly and is aligned in a storage pit.

  At the end of the nuclear fuel cycle, the fuel assemblies that have become unusable after burning must be thermally cooled, so they are stored in a spent fuel storage rack and stored in a storage pit (spent fuel pool). Stored refrigerated for a period of time.

  In the current nuclear power plant, as the spent fuel storage rack, a floor support type fixed to the floor of the storage pit or a wall support type fixed to the wall of the storage pit is mainly used.

  By the way, such floor-supported and wall-supported spent fuel storage racks are difficult to cope with the increase in the amount of spent fuel storage, and the seismic isolation effect is achieved to some extent by the effect of water addition of water when an earthquake occurs. However, when a large earthquake occurs, the load acting on the support increases and the seismic tolerance tends to decrease.

  Therefore, the adoption of free-standing racks (self-supporting storage racks) having high earthquake resistance as spent fuel storage racks is currently being studied, and tests for grasping behavior during earthquakes are being carried out (for example, patent documents) 1).

Japanese Patent No. 4745786

  Here, the self-supporting storage rack as described above exhibits complicated behavior such as sliding and rocking during an earthquake or the like. In addition, since a plurality of self-supporting storage racks are installed side by side in the storage pit, if sliding or locking occurs, adjacent spent fuel storage racks collide with each other, further affecting the behavior of the spent fuel storage racks. The problem was that the overall behavior evaluation was complicated.

  In particular, the rocking tends to promote sliding, and the larger the rocking, the larger the sliding amount and the sliding behavior. In addition, since a large load is applied to the rack legs when rocking occurs, it is required to stabilize the response behavior during an earthquake in order to maintain the soundness of the structure.

  In view of the above, an object of the present invention is to provide a fuel storage rack capable of stabilizing the behavior by suppressing the rocking against a shake during an earthquake or the like.

  A fuel storage rack according to a first aspect of the present invention for solving the above-described problems includes a rack main body portion that stores a large number of rack cells in which fuel assemblies are stored, and a plurality of rack leg portions that support the rack main body portion. A fuel storage rack that is arranged in a storage pit and that supports the rack body portion so that the rack leg portion is slidable with respect to the floor surface of the storage pit from the lower surface of the rack body portion. A vertical plate that hangs down in the longitudinal direction of the rack main body and has a vertical length shorter than that of the rack legs, and a width direction of the rack main body from the lower end of the vertical plate. A fin having an extending horizontal plate and a flow path that is provided on the same plane as the horizontal plate and allows the cooling water in the storage pit to pass in a direction orthogonal to the horizontal plate are provided.

  A fuel storage rack according to a second aspect of the present invention for solving the above problem is the fuel storage rack according to the first aspect of the present invention, wherein the flow path is a through hole formed in the horizontal plate. Features.

  The fuel storage rack according to a third aspect of the present invention for solving the above problem is the fuel storage rack according to the first aspect, wherein a plurality of the fins are arranged along the longitudinal direction of the rack body. The flow path is a gap provided between the adjacent fins.

  A fuel storage rack according to a fourth aspect of the present invention for solving the above problem is the fuel storage rack according to the second or third aspect of the present invention, wherein the rack leg portion extends from the outer peripheral edge of the lower surface of the rack body portion. The horizontal plate is fixed at a spaced position, and the horizontal plate is disposed between the outer peripheral edge of the lower surface of the rack body and the rack leg.

  According to the fuel storage rack according to the present invention described above, it is possible to stabilize the behavior by suppressing the rocking generated in the fuel storage rack against a shake during an earthquake or the like.

It is a perspective view which shows typically the fuel storage rack which concerns on Example 1 of this invention. It is a top view which shows the fin of the fuel storage rack which concerns on Example 1 of this invention. FIG. 3 is a sectional view taken along line III-III in FIG. 2. It is a side view which expands and shows a part of fuel storage rack which concerns on Example 1 of this invention. It is another side view which expands and shows a part of fuel storage rack which concerns on Example 1 of this invention. It is a perspective view which shows typically the fuel storage rack which concerns on Example 2 of this invention. It is a top view which shows the fin of the fuel storage rack which concerns on Example 2 of this invention. It is VIII-VIII sectional drawing of FIG.

  Hereinafter, the details of the fuel storage rack according to the present invention will be described with reference to the drawings.

  A fuel storage rack according to Embodiment 1 of the present invention will be described with reference to FIGS.

  As shown in FIG. 1, in this embodiment, the fuel storage rack 1 includes a base plate 11, a cell storage portion 12, a plurality (five in this embodiment) of rack legs 13, and a plurality (two in this embodiment). This is a self-supporting rack configured with the fins 14.

  In the present embodiment, a rack main body portion is constituted by the base plate 11 and the cell storage portion 12, and the rack leg portion 13 is slidable with respect to the floor 3 of the storage pit (see FIG. 4 and the like). Support. A plurality of such fuel storage racks 1 are arranged side by side in the storage pit.

  The base plate 11 is composed of a plate body formed in a substantially rectangular shape when viewed from above. The cell storage portion 12 is formed in a substantially rectangular shape and is fixed on the base plate 11. The cell storage unit 12 stores N (N = 70 in FIG. 1) rack cells (vertical cells) 2 arranged in a plurality of columns (7 × 10 columns in FIG. 1). The rack cell 2 is a rectangular tube and stores spent fuel taken out from the nuclear reactor. The rack legs 13 are fixed to the vicinity and the center of the lower corners of the base plate 11 to support the base plate 11 and the cell storage portion 12. As shown in FIG. 1, the fins 14 extend on the bottom surface of the base plate 11 and outside the rack legs 13 along the long side direction (hereinafter referred to as the longitudinal direction) of the base plate 11.

  As shown in FIGS. 1 to 3, the fins 14 are a plate-like vertical plate 14a hanging from the lower surface of the base plate 11, and a horizontal direction perpendicular to the vertical plate 14a from the lower end of the vertical plate 14a. And a horizontal plate 14b extending toward the portion 13 side, and is formed in an L shape in sectional view. The horizontal plate 14b is formed with one through hole 14c penetrating in the vertical direction. The through-hole 14c extends along the longitudinal direction of the fin 14 at a position spaced a predetermined width from the outer peripheral edge of the horizontal plate 14b.

  Furthermore, as shown in FIG. 4, the vertical length of the vertical plate 14a is shorter than the vertical length of the rack leg 13 by a predetermined length L1. Further, the length of the horizontal plate 14b in the direction orthogonal to the vertical plate 14a is shorter than the distance from the vertical plate 14a to the rack leg 13 by a predetermined length L2. As a result, the horizontal plate 14b and the floor 3 of the storage pit, and the horizontal plate 14b and the rack leg 13 are separated from each other.

  The predetermined length L1 is set such that the fins 14 come into contact with the floor 3 of the storage pit when the fuel storage rack 1 is tilted by rocking during an earthquake or the like. By making contact with the surface 3, the fin 14 functions as a stopper so that the fuel storage rack 1 can be prevented from overturning. The predetermined length L2 is set to such a length that the horizontal plate 14b can be prevented from coming into contact with the rack leg portion 13 and the size of the through hole 14c can be sufficiently secured.

  According to the fuel storage rack according to the present embodiment configured as described above, the cooling water in the storage pit passes through the through holes 14c of the fins 14 as shown by arrows in FIG. By doing so, damping due to the oliffin effect occurs, and locking of the fuel storage rack 1 can be suppressed.

  Also, if the locking of the fuel storage rack 1 is increased by providing the fins 14 on the outside of the rack legs 13, the fins 14 themselves, specifically, the lower end of the vertical plate 14a is the bottom of the storage pit. It is possible to directly prevent the fuel storage rack 1 from overturning.

  In addition, this invention is not limited to the Example mentioned above, A various change is possible in the range which does not deviate from the meaning of this invention. For example, in this embodiment, an example in which one through hole 14c is provided in the fin 14 is shown, but the number of through holes is not limited to one, and a plurality of through holes are arranged in the longitudinal direction or the short side direction (hereinafter referred to as the width direction) of the base plate 11. The number and shape of the base plate 11 that can generate damping by passing cooling water through the through-holes against shaking during an earthquake, such as by arranging a plurality in the longitudinal direction and width direction of the base plate 11. That's fine.

  In the present embodiment, the horizontal plate 14b is extended from the lower end of the vertical plate 14a toward the rack leg 13 side. However, the vertical plate 14a is spaced a certain distance from the outer edge of the long side of the base plate 11. Fins 14 are arranged so that the horizontal plate 14b extends in the horizontal direction perpendicular to the vertical plate 14a from the lower end of the vertical plate 14a and extends in the opposite direction to the rack leg 13 while being fixed at a spaced position. It doesn't matter.

  In this embodiment, the fin 14 is composed of the vertical plate 14a and the horizontal plate 14b and is L-shaped in cross-section. However, the fin 14 has a shape of a vertical plate fixed to the base plate 11. And a horizontal plate that has a through-hole, and that can generate damping by passing cooling water through the through-hole when rocking of the fuel storage rack 1 occurs due to shaking during an earthquake or the like. For example, the horizontal plate may be formed in contact with the lower end of the vertical plate in a T-shape in cross section, and a through hole may be provided with the vertical plate interposed therebetween.

  Moreover, although the example which installs the fin 14 in the outer side with respect to the rack leg part 13 was shown in the present Example, the position which installs the fin 14 is not limited to the Example mentioned above. However, if the fins 14 are installed outside the rack legs 13, when the locking of the fuel storage rack 1 is increased as described above, the fins 14 are tilted by contacting the bottom surface 3 of the storage pit. The fuel storage rack 1 can be directly supported, which is more preferable.

A fuel storage rack according to Embodiment 2 of the present invention will be described with reference to FIGS. 6 and 7.
In this embodiment, a plurality of (eight in this embodiment) fins 16 shown in FIGS. 6 to 8 are used instead of the fins 14 of the fuel storage rack according to Embodiment 1 shown in FIGS. 1 to 5 and described above. Is. Other configurations are substantially the same as those described in the first embodiment, and hereinafter, members having the same functions are denoted by the same reference numerals, and redundant description is omitted.

  As shown in FIGS. 6 to 8, the fins 16 are arranged on the lower surface of the base plate 11 on the outer side of the rack leg portion 13 at regular intervals of four along the long side direction of the base plate 11. The fins 16 are a plate-like vertical plate 16a that hangs from the lower surface of the base plate 11, and a horizontal plate 16b that extends from the lower end of the vertical plate 16a in a horizontal direction perpendicular to the vertical plate 16 and toward the rack leg 13 side. And is formed in an L shape in a sectional view. Note that, unlike the fin 14 described in the first embodiment, the fin 16 does not include a through hole.

  Further, similar to the fin 14 shown in FIG. 4 and described above, the vertical length of the vertical plate 16a is shorter than the vertical length of the rack leg 13 and is orthogonal to the vertical plate 16a of the horizontal plate 16b. The length in the direction to be reduced is shorter than the distance from the vertical plate 16a to the rack leg 13. As a result, the horizontal plate 16b and the floor 3 of the storage pit, and the horizontal plate 16b and the rack leg 13 are in a state of being separated from each other.

  According to the fuel storage rack according to the present embodiment configured as described above, like the fuel storage rack according to the first embodiment, the cooling water in the storage pit is adjacent to the adjacent fins 16 with respect to shaking during an earthquake or the like. By passing through the gap, damping due to the oliffin effect occurs, and locking of the fuel storage rack 1 can be suppressed.

Also, if the locking of the fuel storage rack 1 is increased by providing the fins 16 on the outside of the rack legs 13, the fins 16 themselves, specifically, the lower end of the vertical plate 16a is the bottom of the storage pit. It is possible to directly prevent the fuel storage rack 1 from overturning.
In addition, since it is not necessary to provide a through hole in the horizontal plate 16b, the fins 16 can be easily manufactured as compared with the fuel storage rack according to the first embodiment.

  In addition, this invention is not limited to the Example mentioned above, A various change is possible in the range which does not deviate from the meaning of this invention. For example, in the present embodiment, an example in which eight fins 16 are used has been described. However, when the shaking occurs during an earthquake or the like, the fins 16 are configured so that the cooling water passes through the gap between adjacent fins so that the fuel storage rack. The number of fins 16 is not limited to the above-described embodiment as long as damping can be generated for one.

  Further, like the fins 14 described in the first embodiment, in this embodiment, the fins 16 are arranged with respect to the vertical plates 16a so that the horizontal plates 16b are positioned on the rack leg 13 side. You may make it arrange | position 16a at the rack leg part 13 side with respect to the horizontal board 16b.

  In the present embodiment, the fin 16 is composed of the vertical plate 16a and the horizontal plate 16b and is L-shaped in sectional view. However, the fin 16 has a shape of the vertical plate 16a fixed to the base plate 11. In addition, a horizontal space capable of generating a damping for the vibration of the fuel storage rack 1 by passing the cooling water when the vibration of the fuel storage rack 1 occurs due to the occurrence of a shake during an earthquake or the like. For example, the fin 16 is formed so that the horizontal plate abuts the lower end of the vertical plate in a T-shape in cross section. A rod-like member is used instead of the vertical plate, and the rod-like member is formed. A horizontal plate may be provided at the lower end of the member.

  The present invention is suitable for application to a self-supporting fuel storage rack in which a fuel assembly is stored and aligned in a storage pit.

DESCRIPTION OF SYMBOLS 1 Fuel storage rack 2 Rack cell 3 Storage pit floor 11 Base plate 12 Cell storage part 13 Rack leg part 14, 16 Fin 14a, 16a Vertical plate 14b, 16b Horizontal plate 14c Through-hole

Claims (4)

A rack main body portion that stores a large number of rack cells that store fuel assemblies and a plurality of rack leg portions that support the rack main body portion are arranged in a storage pit, and the rack leg portions are stored in the storage pit. In the fuel storage rack that supports the rack body so as to be slidable with respect to the floor surface of the pit,
A vertical plate that hangs down from the lower surface of the rack body along the longitudinal direction of the rack body and has a vertical length shorter than that of the rack legs, and the rack from the lower end of the vertical plate. A fin comprising a horizontal plate extending in the width direction of the main body,
A fuel storage rack, comprising: a flow path provided on the same plane as the horizontal plate and allowing cooling water in the storage pit to pass in a direction perpendicular to the horizontal plate. The fuel storage rack according to claim 1, wherein the flow path is a through hole formed in the horizontal plate. A plurality of the fins are arranged along the longitudinal direction of the rack body,
The fuel storage rack according to claim 1, wherein the flow path is a gap provided between the adjacent fins. The rack leg is fixed at a position spaced from the outer peripheral edge of the lower surface of the rack body,
4. The fuel storage rack according to claim 2, wherein the horizontal plate is disposed between an outer peripheral edge of the lower surface of the rack body and the rack leg.

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