JP2003307588A - Fixing method between spent fuel racks - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve earthquake resistance by integrating, in a spent fuel pool, sub-assemblies of racks manufactured in a factory, to shorten and quicken work, and to improve reliability, in remodeling work of a spent fuel rack. <P>SOLUTION: In the remodeling work of the spent fuel rack for replacement, a coupling hardware 3 or 4 is mounted on the peripheral part of a spent fuel rack body 1 for replacement to form a module, and the coupling hardwares 3, 4 of the adjacent modularized rack are piled up mutually and coupled by inserting a coupling plate or a rod into the coupling hardwares or the like, to thereby fix the spent fuel racks. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of fixing spent fuel racks, and more particularly, to a method of fixing a wall-support type spent fuel rack for replacement, which is standard in domestic PWRs. The present invention relates to a fixing method for connecting racks to each other and fixing the racks.

[0002]

2. Description of the Related Art Basically, spent fuel taken out from a nuclear reactor is cooled in a spent fuel storage pool of a power plant for a certain period of time and then transported to a reprocessing plant for reprocessing.
Therefore, the spent fuel storage pool of the current power plant has a capacity that is premised on sequential transportation to the reprocessing plant. However, due to uncertainties regarding reprocessing, it is extremely important to increase spent fuel storage capacity and storage margin at each power plant.

In recent years, there is a plan to reinforce the spent fuel storage rack to increase the storage capacity at each power plant. However, it is necessary to perform the construction while the fuel is stored in the pool, and due to the earthquake resistance. It is necessary to make the structure satisfying the requirement of 1), and the structure is limited.

FIG. 7 and FIG. 8 show one example of a fixing mode of a spent fuel rack which is currently performed, and the existing spent fuel rack 13 is made of horizontal stainless steel called up and down called a support plate. A square tube type is inserted and fixed in a square hole 12 provided in the plate 11.

The support plates 11 are provided at two positions, an upper part and a lower part, of the rack 13, and by being fixed to fixing metal fittings and holding metal fittings 15 fixed to the pool wall 14, they support and restrain the movement during an earthquake. However, it is a structure that is allowed to move during thermal expansion. In the refurbishment work (re-racking work) of the spent fuel rack for replacement, the storage capacity is generally increased without changing the basic structure of fixing to the pool wall, as shown in the figure. As described above, the existing support plate 11 is cut, and the new used fuel rack and the connecting plate are fixed by bolts.

[0006]

However, in the above case,
Considering the earthquake resistance, it is necessary to support the rack from two directions, and if the wall of the spent fuel pit (pool) is used, the rack installed in the pit cannot be divided into four or more. For this reason, the size of the replacement rack becomes large for a large spent fuel pit, which poses a problem in terms of transportation restrictions and equipment restrictions such as lifting cranes. Therefore, in the past, when the size became large, measures such as assembling the rack at the site were taken instead of assembling the rack in the factory, but the construction itself is a remote work underwater, so the rack structure However, there was a problem with restrictions such as assuring assembly accuracy.

In addition, the spent fuel rack must be designed and manufactured so as to have a fuel criticality prevention function, a seismic resistance function, a heat removal function, etc., and high processing accuracy is required. It is desirable to be manufactured up to. However, in order to manufacture a spent fuel rack to a finished product,
Considering manufacturing equipment, transportation restrictions after manufacturing, etc., the size of the rack will be restricted, and the conditions of the replacement rack will not be satisfied.

The present invention copes with the above-mentioned situation, and in particular, by finding out that the subassembly of the rack manufactured in the factory is integrated in the spent fuel pool, the seismic performance is improved and the reliability of the on-site construction is improved. The purpose is to improve the property and speed up.

[0009]

That is, the feature of the present invention that achieves the above object is to modularize spent fuel racks for replacement and to connect the modularized spent fuel racks by a coupling means. This is to fix the adjacent spent fuel racks.

The invention according to claim 2 is one of the specific forms thereof, in which connecting metal fittings are attached to the outer peripheral portion of the spent fuel rack body for replacement, and the connecting metal fittings of the adjacent racks are superposed on each other. , Connecting the racks by inserting a connecting plate or rod into the connecting fitting. In this case, the connecting plate or bar is preferably a member that can be fixed by caulking or the like. In addition, when connecting the spent fuel racks, the upper and lower portions of the spent fuel racks are connected to the upper and lower two positions, as required, by aligning with the fixed position in the height direction of the spent fuel racks and the pool wall.
Most commonly, there are two locations above and below.

[0011]

According to the fixing method of the present invention, the spent fuel racks are connected to each other. Therefore, even when an earthquake occurs, the force is transmitted to the adjacent racks through the connecting portion, thereby improving the seismic performance. .

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Specific embodiments of the fixing method of the present invention will be described below with reference to the accompanying drawings. 1 and 2 show an example of a modular construction of a spent fuel rack, which is an essential part of carrying out the method of the present invention, and FIG. 3 shows details of a connecting portion of adjacent racks.

In these figures, 1 is a spent fuel rack main body, 2 is a fuel assembly inserted in the fuel rack 1,
Reference numerals 3 and 4 denote connecting fittings attached to the reinforcing plate 6 on the outer periphery of the fuel rack body 1, and 5 denotes connecting plates or rods inserted into the connecting fittings 3 and 4.

In the figure, the spent fuel rack 1 is modularized by providing connecting fittings on the outer periphery as described above, and the connecting fittings 3 and 4 are arranged for each row of fuel cells and in the wall height direction. Although it is installed at two places above and below the support position, it may be provided at one place at the upper or lower part or at three or more places if necessary. However, in terms of work, it is preferable to install the connecting metal fittings at the upper and lower two positions, which correspond to the fixed positions of the fuel rack and the pool, as the connecting portions as shown in the figure. A plurality of connecting fittings are usually installed in the circumferential direction on the outer circumference of the spent fuel rack body 1.

Further, it is preferable that the connecting metal fittings are arranged so that the adjacent racks are displaced from each other in the vertical position to be connected to each other so that they are overlapped with each other at the time of connection.
Further, when the connecting metal fittings adjacent to each other are overlapped with each other, it is preferable that the connecting plate or rod 5 can be inserted into the metal fittings as shown in FIG. 3 in order to ensure the connection. Is. However, needless to say, the present invention is not limited to the above, and the connecting metal fittings 3 and 4 of adjacent racks may be fitted to each other, which is not a problem. Since the connecting plate or rod 5 to be inserted into the connecting metal fittings 3 and 4 is fixed, it is preferable that it can be securely fixed to the connecting metal fitting by caulking or the like. Select the necessary one from the calculation.

The method of the present invention is based on the above-described modularized structure of the racks. The racks to be connected to the new spent fuel racks already attached to the wall of the spent fuel pit are immersed in the racks to be connected to each other. After the metal fittings 3 and 4 are aligned, the connection plate or the rod 5 is inserted to fix the metal fittings. At this time, the connecting portion is provided for each row of the fuel cells as described above, but normally, the connecting portion is provided at two upper and lower positions in combination with the supporting position of the wall, and the upper and lower portions are connected for each row.

FIGS. 4 to 6 show examples of the structure of the fuel racks thus connected, in which the metal fittings 3 and 4 of the adjacent racks are overlapped with each other and the connection plates or rods 5 are overlapped with each other. The connection configuration of the racks inserted through the connection fittings 3 and 4 is shown. In the figure, the reference numeral is FIG.
~ It is the same as that shown in Fig. 3, and the same reference numerals indicate the same parts.

The spent fuel rack thus constructed is
Since the racks are connected to each other, the force is transmitted to the adjacent racks through the connecting portion even when an earthquake occurs, and good seismic performance is exhibited.

[0019]

As described above, according to the present invention, the spent fuel racks for replacement are modularized, and the adjacent spent fuel racks that are modularized are connected by connecting means such as connecting metal fittings. It is a method of fixing the space,
By modularizing the spent fuel rack, it can be used as a replacement for the existing rack, and the spent fuel rack can be miniaturized, making it possible and easy to optimize the spent fuel rack design. Since the rack can be made smaller, it has the remarkable effect of increasing the flexibility of on-site construction and the fact that the on-site rack assembly is not required and the construction can be shortened. ing. In addition, it is possible to manufacture a completed spent fuel rack in a factory, and it is possible to provide a highly accurate rack with excellent economical efficiency.

[Brief description of drawings]

FIG. 1 is a partially cutaway front view showing a modularized structure of a fuel rack in a fixing method of the present invention.

FIG. 2 is a plan view of FIG.

FIG. 3 is an enlarged view showing details of a connecting portion.

FIG. 4 is a partially cutaway front view showing the structure of a fuel rack fixed by the method of the present invention.

FIG. 5 is a plan view of FIG.

FIG. 6 is an enlarged cross-sectional view showing details of a connecting portion.

FIG. 7 is a schematic view of a use surface showing a fixing aspect of a conventional spent fuel rack.

FIG. 8 is a plan view of FIG.

[Explanation of symbols]

1 Spent fuel rack body 2 Fuel assembly 3,4 connecting metal fittings 5 Plates or rods for connection 6 Reinforcement plate

Claims (4)

[Claims] Claim: What is claimed is: 1. In the refurbishment of a replacement spent fuel rack, the replacement spent fuel rack is modularized, and the modularized spent fuel racks are connected to each other by a connecting means so as to be adjacent to the used fuel. A method for fixing spent fuel racks, characterized by fixing between racks. 2. A connecting metal fitting is attached to an outer peripheral portion of a spent fuel rack main body for replacement, the connecting metal fittings of adjacent racks are overlapped with each other, and a connecting plate or rod is inserted into the connecting metal fitting. The method for fixing the spent fuel racks according to claim 1, wherein adjacent spent fuel racks are connected to each other by. 3. The fixing method between spent fuel racks according to claim 2, wherein the connecting plate or rod is a member that can be fixed by caulking or the like. 4. The spent fuel rack according to claim 1, 2 or 3, wherein the connecting positions between the spent fuel racks are two upper and lower positions which correspond to the fixed positions of the spent fuel rack and the pool wall in the height direction. Fixing method between.