JPH0440398A - Fuel storage rack - Google Patents

Abstract

PURPOSE:To facilitate the assembly and reduce the size of the whole rack, and to improve the reliability by increasing the strength of a weld zone by assembling storage racks which are formed by welding continuous welded and fixed plates previously at the four corner parts of a rectangular tube. CONSTITUTION:Two places of connecting plates 11 are fitted strongly by welding 12 to the round parts 22 of the four corners of rectangular tube 1 and accurate machining is carried out to specific diagonal size M. Then when rectangular tubes 1 are assembled zigzag, rectangular tubes 1 in a 1st array are arranged alternately and welded to a sealing plate 7 and rectangular tubes 1 in a 2nd array are arranged alternately so as to form a B storage cell 9; and connecting plates 11 adjoin at the corner parts of the 1st and 2nd arrays are welded 13, thereby forming A storage cells 18 in the rectangular tubes 1 and B cells 19 surrounded with the outer peripheries of the rectangular tubes 1. Consequently, the arrangement size setting of the rectangular tubes 1 at the time of assembly is facilitated to improve the operation efficiency, the arrangement size accuracy is improved, and the size is reduced more.

Description

Detailed Description of the Invention [Object of the Invention] (Industrial Application Field) The present invention mainly relates to a fuel storage system for temporarily storing spent fuel assemblies taken out from a nuclear reactor in a fuel storage pool. Regarding the rack.

(Prior Art) Normally, in a nuclear power plant, spent fuel is taken out after a certain period of operation, cooled and stored in a fuel storage pool to remove the decay heat of the fuel.

A conventional fuel storage rack for spent fuel is shown in a plan view in FIG. 5, a partially cutaway front view in FIG. 6, and FIG. 7.

As shown in the enlarged plan view of the main part in FIG.
are arranged in a staggered manner on a base 2, and the base 2 is fixed to the bottom surface of the fuel storage pool 3 with bolts 20 and nuts 21.

The rectangular tube body 1 has a size that can accommodate one fuel assembly 4 at a time, and is made by bending metal plates and welding the joints, and has a square cross section with rounded corners.

The plurality of rectangular cylinders 1 are combined in a houndstooth pattern, as shown in FIG. , through which they are joined by welding 6.

Further, at the outermost periphery, the space between adjacent rectangular cylinders 1 is closed with a closing plate 7, and the corners are welded. Note that a spacer 7a is attached to the inside of the closing plate 7 to match the external dimensions of the fuel assembly 4 to be accommodated. As a result, the fuel assembly 4 is inserted and housed in the A storage cell 8 in the rectangular cylinder 1 and the B storage cell 9 which is surrounded by the outer periphery of the rectangular cylinder 1.

This fuel storage rack for spent fuel is constructed by setting the corner radius and diagonal dimensions to appropriate dimensions, and by adjusting the thickness of the flat par 5, all square cylinders 1 are installed in each fuel assembly 4. Compared to a fuel storage rack in which the total number of storage cells is the same as the A storage cell 8, there is an advantage that the pitch between each storage cell can be made smaller. That is, the outer surfaces of the rectangular tubes 1 can be arranged in a straight line, or the thickness portions of the rectangular tubes 1 can overlap with each other, so that the overall external dimensions can be reduced.

(Problem to be Solved by the Invention) However, in the conventional spent fuel rack, the rectangular cylinder body 1 is made by bending metal plates and welding the joints.
In addition, since corners are formed with radii, it is difficult to maintain a constant diagonal dimension between the radii, and the tolerance becomes large, which is an obstacle to reducing the overall external dimensions.

In addition, in one assembly, as shown in FIG. 7, first, every other rectangular tube body 1 in the first row is lined up and connected to the closing plate 7 by welding. Next, the rectangular cylinders 1 in the second row are connected to each other by welding 6 via a flat flat parr 5 so as to form a B storage cell 9. In this case, since welding from within the B storage cell 9 is impossible, the welding 6 between the rectangular cylinders 1 is only on one side of the flat par 5, resulting in unstable strength.

That is, if a force is applied to the unwelded portion of the flat par 5 in a direction that causes the rectangular tube bodies 1 to separate from each other, there is a risk that the weld 6 will easily break.

The present invention has been made in view of the above, and its object is to provide a fuel storage rack that has high strength and precision and is easy to assemble by combining rectangular cylinders arranged in a staggered manner.

[Structure of the invention]

(Means for Solving the Problems) In order to achieve the above object, in the fuel storage rack according to the present invention, connecting plates are firmly welded and fixed in advance to the four corners of the rectangular cylinder constituting the fuel storage rack. Then, the diagonal dimensions between the connections are machined with high precision.

The processed rectangular cylinders are assembled in a houndstooth pattern, the connecting plates are welded to each other at each corner, and the adjacent rectangular cylinders on the outermost side are connected with a closing plate to form a storage cell. It is accomplished by

(Function) In the fuel storage rack configured in this manner, the plurality of rectangular cylinders arranged in a staggered manner are arranged in a staggered manner, with connection plates welded to the four corners in advance, and the diagonal dimensions The diagonal dimension between the rounded parts of the rectangular cylinder can be set with high precision through machining.

Since it can be assembled without any influence, the dimensional accuracy of the storage cell arrangement is improved. Furthermore, since the connecting plate is welded to the rectangular cylinder in advance, it becomes possible to weld the connecting plate to the rectangular cylinder on both sides, and instability in strength can be eliminated. As described above, the dimensional accuracy and strength can be improved and the external size can be made smaller.

(Example) An example of the present invention will be described with reference to FIGS. 1 to 4. Components that are the same as those of the prior art shown in FIGS. 5 to 7 are designated by the same reference numerals, and detailed explanations of the structures will be omitted.

Here, FIG. 1 is a plan view of a fuel storage rack according to an embodiment of the present invention, FIG. 2 is a partially cutaway side view, and FIG. 3 is a storage cell in the process of attaching a connecting plate to a rectangular cylinder. Plan view shown, 4th
The figure is an enlarged view of the main part of FIG.

A large number of rectangular cylinders 1 are arranged in a staggered manner, and as shown in FIG. 3, connecting plates 1 are firmly attached to the rounded portions 22 at the four corners by welding 12 at two locations in advance.

Thereafter, the paired dimension M is precisely finished to a predetermined dimension by machining.

The rectangular cylinders 1 to which the connecting plates 11 are attached and whose diagonal dimension M has been machined are assembled in a houndstooth pattern as shown in FIG. Line up every other body,
0-order second row rectangular cylinder body 1 connected to the closing plate 7 by welding
are arranged every other cell so as to form a B storage cell 19, and
Connecting plates 11 adjacent to each other at the corners of the rectangular cylinders 1 in the row and the rectangular cylinders 1 in the second row are joined together by welding 13. In this case, welding 13 is preferably full penetration welding in the width direction of the connecting plate 11. For example, the weld bead width is narrow and deep penetration is possible, making it ideal for shape welding of thick plates. A certain type of electron beam welding may be used.6 However, the method of welding 13 is not limited to the above, and any appropriate method may be used. after that,
The third and fourth rows are assembled in sequence to form the required configuration.

As a result, the A storage cell 18 within the square tube 1 and the B storage cell 9 surrounded by the outer periphery of the square tube 1 are formed by a large number of square tubes 1 arranged in a staggered manner.

A large number of rectangular cylindrical bodies 1 are connected at the lower part to a base 2 to constitute a fuel storage rack, and are fixed to the bottom surface of the fuel storage pool 3 with bolts 20 and nuts 21.

Next, the effect of the above configuration will be explained. When arranging a large number of rectangular cylinders 1 in a staggered manner, connecting plates 11 are attached in advance to the rounded portions 22 at the four corners of the rectangular cylinders 1, and the diagonal dimension M is
is set with high accuracy through machining, it is easy to set the placement dimensions of the rectangular cylinder l during assembly, which increases work efficiency, improves placement dimensional accuracy, and allows for further miniaturization. .

Furthermore, the connecting plate 11 is connected to the rectangular tube body 1 from both sides by welding 12, and the rectangular tube body 1 is connected to the rectangular tube body 1 when configured in a staggered manner.
Since the connection between the connecting plates 11 can be made by complete penetration welding, the strength and reliability of the welded portion can be improved.

〔Effect of the invention〕

As described above, according to the present invention, the fuel storage rack can be easily assembled, the dimensional accuracy of the storage cells and the rack as a whole can be improved, and the external size can be reduced, and reliability can be improved by increasing the strength of the welded portion.

[Brief explanation of drawings]

FIG. 1 is a plan view of a fuel storage rack according to an embodiment of the present invention, FIG. 2 is a partially cutaway side view of an embodiment of the present invention, and FIG. 3 is an assembly process of an embodiment of the present invention. 4 is an enlarged plan view of the main part of FIG. 1, FIG. 5 is a plan view of a conventional fuel storage rack, and FIG. 6 is a partially cutaway side view of a conventional fuel storage rack. FIG. 7 is an enlarged plan view of the main part of FIG. 5. DESCRIPTION OF SYMBOLS 1... Square cylinder, 2... Base, 7... Closing plate, 7a... Spacer, 8.18... A
Storage cell 9, 19...B storage cell 11...Connecting plate, 12.13...Welding agent Patent attorney
Noriyuki Chika 1 Figure 1 Figure Figure Figure Figure Figure

Claims (1)

[Claims] A fuel system in which a plurality of rectangular cylinders capable of storing one fuel assembly each are arranged in a staggered manner, and a square space formed inside the rectangular cylinders and the outside of the rectangular cylinders is used as a storage cell for the fuel assembly. In the storage rack, a connecting plate is arranged at the corner of the outer side of each rectangular cylinder, and this connecting plate is machined in a diagonal direction, and opposing connecting plates are joined by welding and assembled. 1. A fuel storage rack characterized in that adjacent rectangular cylinders are connected at the outermost sides of the rectangular cylinders by a closing plate, and a base is installed at the bottom.