JP2000275385A - Fuel rack upper support structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve placing work capability of spacers between racks and aseismatic structure of the rack. SOLUTION: In a fuel rack 1, an integrated spacer 3 of structure supporting the upper part is provided and the integrated spacer 3 consists of a tapered spacer 4 filling the gap between fuel racks 1 and between the fuel rack 1 and fuel pool wall 2, and a frame 5 combining each spacer 4 in one. The integrated spacer 3 can be placed on the fuel rack 1 by the self-weight of whole integrated spacer 3 without fixing by directly welding to the fuel rack 1 and fuel pool wall 2 so that whole fuel rack and fuel pool wall are supported in one in the constitution.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spent fuel storage rack for storing spent fuel assemblies generated in a nuclear power plant, and more particularly to a fuel rack upper support structure having improved earthquake resistance.

[0002]

2. Description of the Related Art In a nuclear power plant, a spent fuel assembly taken out of a reactor core is cooled in a spent fuel storage pool provided in the nuclear power plant until it is carried out to a reprocessing plant. , Stored. In this case, the fuel assemblies are stored in a spent fuel storage rack which constitutes a spent fuel storage cell using stainless steel or a neutron absorbing material provided at the bottom of the fuel pool. One storage rack stores dozens of fuel assemblies vertically.

The fuel rack is in the shape of a vertically long rectangular parallelepiped that accommodates several tens of fuel assemblies, and the upper surface is open to accommodate the fuel assemblies, but the vertical and horizontal steel materials forming the rectangular parallelepiped and reinforcing them. The fuel cell is constituted by a slanted steel material and a fuel storage cell forming a partition plate between the side plate, the bottom plate, and the fuel assembly inside, and has a highly rigid structure. In addition, the fuel rack is fixed at the lower part via a foundation bolt by an anchor embedded in the floor of the spent fuel storage pool.

FIG. 5 shows a configuration example of a conventional spent fuel storage rack.

In FIG. 5, this fuel rack 100 is
A fuel storage cell 101 for storing a spent fuel assembly, a steel material 102 for forming and reinforcing a fuel rack, has a highly rigid structure, and has a spent fuel storage pool floor 10.
3. The spent fuel storage pool wall 104 is fixed via anchor bolts 106 by anchors 105 buried in advance in the fuel pool floor.

As described above, in the prior art, the fuel rack 10
No. 0 accommodates the fuel assembly and is securely fixed to the fuel pool floor 103, but the height is higher than the fixed width. Therefore, when a horizontal force is applied during an earthquake, a very large force acts on the foundation bolt 106 below the fuel rack 100, and there is a problem that the structure is not superior in earthquake resistance.

In Japanese Patent Application Laid-Open No. 10-39087, a support 1 is provided between the fuel rack 100 and between the fuel rack 100 and the fuel pool wall 104 at the upper portion of the fuel rack 100.
07, and the foundation bolt 10 at the lower part of the fuel rack 100 is provided.
6 can be reduced. However, since the supports 107 are provided individually between the fuel racks 100 and between the fuel rack 100 and the fuel pool wall 104, the setting work of the supports 107 has to be performed for each one. There was a problem that it became complicated. Therefore, a structure that supports the upper part of the fuel rack with good installation workability has been required.

[0008]

In the above prior art, although the force acting on the lower part of the fuel rack can be reduced, the support is provided separately between the fuel rack and between the fuel rack and the wall of the fuel pool. Therefore, there is a problem that welding work on site for installing the support on the fuel rack becomes very complicated.

An object of the present invention is to provide a support provided on an upper portion of a fuel rack, which is integrally fixed as a spacer without being fixed to the fuel rack by welding, and transmits a horizontal force at the time of an earthquake to a spent fuel storage pool wall. An object of the present invention is to provide a fuel rack upper support structure capable of improving the seismic resistance of a spent fuel storage rack.

[0010]

In order to achieve the above-mentioned object, an integral spacer which is an upper support structure of a fuel rack according to the present invention is installed without directly welding to a fuel rack and a fuel pool wall. Installation work becomes easy, and workability can be improved.

By providing an integral spacer between the adjacent fuel racks and between the fuel rack and the fuel pool wall to support the fuel rack, the seismic resistance of the fuel rack can be improved. By providing a mechanism capable of appropriately adjusting the position of the spacer, the earthquake resistance can be further improved.

According to the first aspect of the present invention, the conventional support is provided between the fuel racks and between the fuel racks, since the upper spacer of the spent fuel storage rack is installed without being fixed to the fuel rack and the fuel pool wall directly by welding or the like. The workability of the installation work can be greatly improved as compared with the method of fixing between the fuel pool walls. Also, by integrally connecting the spacers on the upper part of the fuel rack by a frame member connecting the spacers, the spacers integrally connected at the time of spacer installation can be installed at once by a crane, and the conventional support can be installed between the fuel racks. The workability of the installation work can be greatly improved as compared with the method of individually providing the installation work. Also,
When installing a spacer on an existing plant where the support above the fuel rack is not installed, as described above, it is necessary to install the spacer by installing it together without fixing it by welding etc. The time required for installation can be greatly reduced, and the amount of radiation exposure during the installation work can be reduced as compared with the conventional installation method. In addition, in the case of installing spacers for an existing plant, since the fuel rack is already installed at the position determined by the foundation bolts, the position of each integrally combined spacer can be set before being brought to the site. , Construction time on site can be shortened.

According to a second aspect of the present invention, there is provided an integrated spacer on an upper portion of a fuel rack according to the first aspect, which fills a gap between a fuel rack and a fuel rack and between a fuel rack and a wall of a fuel pool. A mechanism is provided to adjust the position of the spacer using gravity or the force of a spring so that the spacer can be installed properly, so the entire fuel rack and fuel pool wall are further integrated, improving earthquake resistance. can do.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS With reference to FIGS. 1 to 4, an embodiment of an integral spacer which is an upper support structure of a spent fuel storage rack according to the present invention will be described.

Spent fuel assemblies generated in a nuclear power plant are cooled and stored in a spent fuel storage pool provided in the nuclear power plant until they are carried out to a reprocessing plant.

FIG. 1 shows an embodiment of an upper support structure for a spent fuel storage rack according to the present invention. Fuel rack 1
Is provided with an integral spacer 3 having a structure for supporting the upper part. The integral spacer 3 comprises a tapered spacer 4 for filling the gap between the fuel rack 1 and between the fuel rack 1 and the fuel pool wall 2 and a frame 5 for integrally connecting the respective spacers 4. Spacer 3
Without being directly fixed to the fuel rack 1 and the fuel pool wall 2 by welding or the like, the integral spacer can be installed on the upper portion of the fuel rack 1 by its own weight, and the entire fuel rack and fuel pool wall are integrally supported. can do.

FIGS. 2 to 4 show one embodiment of the upper support structure of the spent fuel storage rack according to the present invention, and the spacers of the upper support structure which fill the gap between the fuel rack and the fuel pool wall. 1 shows a mechanism provided with a mechanism for adjusting the spacer so that the spacer can be properly installed. Tapered spacer 4 constituting integral spacer 3
As shown in FIG. 2, the gap can be filled by freely moving by the hole 6 provided in the frame 5 and the support member 7 of the spacer 4. Further, as shown in FIG. 3, a spring 8 between the spacer 4 and the frame 5 is further provided in the hole 6 provided in the frame 5 and the support member of the spacer 4, so that the spacer 4 can move freely to fill the gap and appropriately fit the spacer 4. Can be installed in In addition, as shown in FIG. 4, in addition to the holes 6 provided in the frame 5 and the support members 7 for the spacers 4, the fixing members 9 are further provided to freely move to fill the gaps and the spacers 4.
Can be properly installed. As described above, the integral spacer 3 restricts the fuel rack 1 and the fuel pool wall 2 only at three points in the vertical direction, and does not fix the other parts by direct welding or the like, and uses the mechanism of FIG. It can be installed on the upper part of the rack 1, and the whole of the fuel rack and the fuel pool wall can be further integrated and supported.

[0018]

According to the present invention, the conventional support is provided between the fuel rack and between the fuel rack and the fuel pool wall in order to install the spacer above the spent fuel storage rack without directly fixing the spacer to the fuel rack and the fuel pool wall. It is possible to greatly improve the workability of the installation work as compared with the method of fixing the work. By integrally connecting the respective spacers on the upper part of the fuel rack by the frame member connecting the spacers, the spacers integrally connected at the time of spacer installation can be installed at once by a crane, and the conventional support is individually provided between the fuel racks. It is possible to greatly improve the workability of the installation work as compared with the method of providing the above.

In the case where the spacer is installed on the existing plant where the support above the fuel rack is not installed, the spacer is installed integrally without fixing by welding or the like as described above. Therefore, the time required for installation can be greatly reduced, and the radiation exposure during the installation work can be reduced as compared with the conventional installation method. In the case of installing spacers for an existing plant, since the fuel rack has already been installed at the position determined by the foundation bolts, the position of each of the integrally connected spacers can be set before being brought to the site. It is possible to shorten the construction period in.

The integral spacers on the upper part of the fuel rack as shown in claim 1 for filling the gaps between the fuel racks and between the fuel racks and between the fuel racks and the wall of the fuel pool can be appropriately installed in the respective gaps. As described above, since the mechanism for adjusting the position of the spacer using the force of gravity or the spring is provided, the entire fuel rack and the fuel pool wall are further integrated, and the earthquake resistance can be improved.

[Brief description of the drawings]

FIG. 1 is a structural view showing an integral spacer on an upper portion of a fuel rack, which integrally supports a fuel rack and a fuel pool wall according to an embodiment of the present invention.

FIG. 2 is a view showing an example of a mechanism for adjusting the integral spacer of FIG. 1;

FIG. 3 is a view showing an example of a mechanism for adjusting the integral spacer of FIG. 1;

FIG. 4 is a view showing an example of a mechanism for adjusting the integral spacer of FIG. 1;

FIG. 5 is a configuration diagram showing a conventional fuel rack and a support above the fuel rack.

[Description of Signs] 1,100: spent fuel storage rack, 2,104: spent fuel storage pool wall, 3: integral spacer, 4 ... tapered spacer, 5 ... frame, 6 ... frame hole, 7 …
Spacer supporting member, 8: spring between frame and spacer, 12: fixing member of spacer to frame, 101 ...
Fuel storage cell, 102: steel material, 103: spent fuel storage pool floor, 105: anchor, 106: foundation bolt, 10
7 ... Support.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Naoki Fukushi 3-2-1 Sachimachi, Hitachi-shi, Ibaraki Prefecture Inside Hitachi Engineering Co., Ltd. (72) Inventor Masaki Nakagawa 3-1-1 Sachimachi, Hitachi-shi, Ibaraki No. 1 Inside Hitachi, Ltd. Hitachi Plant

Claims (2)

[Claims] Claims: 1. A spent fuel storage rack provided for storing and storing spent fuel assemblies generated in a nuclear power plant, comprising: a fuel storage rack between adjacent fuel racks in a spent fuel storage pool; And a spacer that has a shape that fills the gap between the fuel rack and the spent fuel storage pool wall, and that is not fixed to the fuel rack and the fuel pool wall by welding or the like, and that a plurality of integrally joined spacers are placed on top of the fuel rack. And a fuel rack upper support structure, wherein the whole of the fuel rack and the fuel pool wall is integrally supported. 2. In the fuel rack, the spacer of the upper support structure that fills the gap between the fuel rack and the fuel rack and the gap between the fuel rack and the fuel pool wall can be appropriately installed in the respective gaps. 2. A fuel rack upper support structure according to claim 1, further comprising a mechanism for adjusting the height of the fuel rack and the whole of the fuel rack and the fuel pool wall.