JPH05249284A - Spent fuel storage rack - Google Patents

Abstract

PURPOSE:To obtain a spent fuel storage rack with high accuracy and high quality which requires small amount of fusion metal charged in the notch of a connection part, and short time for welding work and brings in little welding thermal distortion of the whole rack during assembling and welding. CONSTITUTION:In a spent fuel storage rack in which square cylinders are arranged in checker pattern, the connection part 2 inserted among the corners of the neighbouring square cylinders has, at a part in the longitudinal direction, a notch part 3 whose bottom has a cross section of a regular triangle or a traoezoid.

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 facility for keeping spent fuel generated in a nuclear power plant in a spent fuel pool at predetermined intervals and in an upright state. In particular, it relates to a spent fuel storage rack suitable for storing spent fuel in high density.

[0002]

2. Description of the Related Art Currently, spent fuel generated in a nuclear power plant keeps a predetermined interval in a spent fuel storage rack installed in a spent fuel storage pool in a reactor building, and
Although they are aligned and held in an upright state, in recent years, it has been desired to increase the storage capacity of the spent fuel storage pool in the reactor building, and it was necessary to increase the fuel storage capacity of the spent fuel storage pool more than before. .. However, since it is difficult to change the shape of the spent fuel storage pool, a more efficient spent fuel storage method has been desired.

As a measure for this, in the prior art, for example, there is a spent fuel storage rack as disclosed in Japanese Patent Laid-Open No. 1-280296.

FIG. 6 shows a rectangular tubular joint portion using a joining member 9 of a spent fuel storage rack according to the prior art disclosed in Japanese Patent Laid-Open No. 1-280296, and FIG. The perspective view which shows an example of the member 9 is shown.

In the spent fuel storage rack according to the prior art, a joining member 9 provided with a simple notch 10 is inserted and interposed between the corners of adjacent rectangular cylinders 1, and the notch 10 is provided. Since the rectangular tubular bodies were fixed to each other by filling all with the deposited metal 5, the amount of deposited metal during assembly and welding of the spent fuel storage rack was large, the welding work time was long, and the thermal deformation of the welding of the entire rack was also large. There was a big problem.

[0006]

In the above prior art, a joining member having a simple cutout is inserted and interposed between the corners of adjacent rectangular tubular bodies, and the weld metal is formed in all the cutouts. Since the rectangular cylinders were fixed to each other by filling them, there was a problem that the amount of deposited metal during assembly and welding of the spent fuel storage rack was large, the welding work time was long, and the thermal deformation of the entire rack was large. there were.

The object of the present invention is to provide a highly accurate and high quality spent fuel, in which the amount of deposited metal at the time of assembling and welding a spent fuel storage rack is small, the welding work time is short, and the welding heat deformation of the entire rack is small. It is to provide a joining member capable of facilitating the manufacture of a storage rack.

[0008]

In order to achieve the above object, in a spent fuel storage rack, a joining member is piled up in a mountain shape so that the bottom of the notch of the joining member has an equilateral triangle in cross section. And

[0009]

The joining member according to the first aspect is inserted and interposed between the corner portions of the rectangular tubular body, and acts to reduce the amount of the weld metal when the notch portion is filled with the weld metal. As a result, it is possible to reduce the working time at the time of assembling and welding the spent fuel storage rack, and to reduce the welding heat deformation of the rack.

The welding leg length acts in the same manner as in the case of the conventional joining member by raising the cross-sectional shape of the bottom of the notch portion of the joining member into a mountain shape so as to form an equilateral triangle. As a result, even if the amount of deposited metal to be filled is reduced,
It is possible to obtain the same strength as that of the conventional joining member.

In the joining member according to the second aspect of the present invention, when the cross-sectional shape of the bottom of the notch is raised in a mountain shape so as to be trapezoidal, the top portion of the mountain-shaped portion is raised when the lateral width of the joining member becomes large. It works so as not to be too high than the surface of the joining member on the side having the notch.
As a result, even in a joining member having a large lateral width, it is possible to obtain the same effect as that of a joining member in which the cross-sectional shape of the bottom of the cutout portion is a triangular shape.

[0012]

[Example] Currently, spent fuel generated in a nuclear power plant is stored and stored in a spent fuel storage pool in a reactor building, but recently, it is desired to increase the storage capacity of this spent fuel storage pool. It is rare. However, since it is difficult to change the shape of the spent fuel storage pool, it is necessary to store spent fuel more efficiently. As a method of doing so, the corner wall thickness of the rectangular cylinder constitutes the rectangular cylinder. For a plurality of rectangular cylinders having corner portions with a radius of curvature that is substantially equal to the other wall thickness, the distance between the outer wall surfaces of the rectangular cylinder becomes substantially equal to the distance between the inner wall surfaces of the rectangular cylinder. By arranging in the same way, it is geometrically arranged in a checkered pattern that allows the highest density, and a joint is provided with a notch in a part of the longitudinal direction between each corner of the rectangular tubular body. There is a spent fuel storage rack in which members are inserted and interposed, and the cutouts are filled with a weld metal by welding to fix the rectangular tubular bodies to each other.

An embodiment of the present invention will be described below with reference to FIGS. 1 to 5.

FIG. 1 is a partial plan sectional view of a spent fuel storage rack using a joining member according to the present invention, in which a plurality of rectangular cylinders 1 arranged in a checkerboard pattern are adjacent to each other. The joining member 2 is inserted between the corners of the rectangular tubular body 1
The state where the two are connected to each other is shown. FIG. 2 is a perspective view showing an example of the joining member 2 according to the present invention, in which the joining member 2 is a chevron portion in which the cross-sectional shape of the bottom of the notch 3 in a part of the longitudinal direction is a regular triangle. 4 is a structure having 4. FIG. 3 is a detailed view of a state where the joining member 2 is attached to the rectangular tubular body, and shows a state in which the notch 3 of the joining member 2 is filled with the welding metal 5 by welding and the square tubular bodies 1 are connected to each other. .. Here, the alternate long and short dash line 6 in the figure indicates the range necessary for storing the spent fuel. FIG. 4 is a side view of the spent fuel storage rack showing the attachment state of the joining member 2 in the longitudinal direction of the rectangular tube body 1. The joining member 2 ensures the strength required as a spent fuel storage rack. In order to
It is a structure that is arranged at several positions in the vertical direction at an appropriate pitch.

FIG. 5 shows another embodiment of the joining member according to the present invention. In this embodiment, when the width 7 of the joining member 2 is increased, the top of the mountain-shaped raised portion is higher than the surface of the joining member 2 on the side having the notch 3 (dotted line portion in the figure). By joining the cross section of the bottom of the notch into a trapezoidal shape in a chevron shape, even in the joining member 2 having a large lateral width 7, the chevron is joined so that the cross section of the bottom of the notch becomes an equilateral triangle. It is possible to ensure the same function as the member 2 for use.

The joining member according to the present invention may be formed by machining stainless steel by machining or other processing methods, or non-metallic materials such as cast stainless steel produced by casting and ceramics. May be Further, this joining member is composed of the above-mentioned materials, which are elements having high neutron absorption ability, such as B, Gd, Sm, Eu
Cd, Dy, In, Er, Ta, Rh, Tm, Lu, H
A material containing one or more elements such as f, Au, Re, and Ag may be used.

[0017]

According to the present invention, the amount of the weld metal filled in the notch portion is reduced by raising the cross-sectional shape of the bottom portion of the notch portion of the joining member in a mountain shape so as to form an equilateral triangle or a trapezoid. The welding work time can be shortened.

Furthermore, since the amount of deposited metal can be reduced and the welding work time can be shortened, it is possible to reduce the welding heat deformation of the entire rack, so that a highly accurate and high quality spent fuel storage rack can be obtained. ..

[Brief description of drawings]

FIG. 1 is a partial plan sectional view of a spent fuel storage rack using a joining member according to the present invention.

FIG. 2 is a perspective view showing an example of a joining member according to the present invention.

FIG. 3 is an explanatory view of a state where a joining member according to the present invention is attached to a rectangular tubular body.

FIG. 4 is a side view of a spent fuel storage rack showing a mounting state of a joining member in a longitudinal direction of a rectangular tubular body.

FIG. 5 is an explanatory view of another embodiment of the joining member according to the present invention.

FIG. 6 is a cross-sectional view of a state where a joining member according to the related art is attached to a rectangular tubular body.

FIG. 7 is a perspective view showing an example of a joining member according to a conventional technique.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Square tube, 2 ... Joining member, 3 ... Notch part, 4 ... Angle part.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yasukata Tamai 3-1-1, Saiwaicho, Hitachi-shi, Ibaraki Hitachi Ltd. Hitachi factory (72) Inventor Takashi Matsumoto 3-chome, Hitachi-shi, Ibaraki No. 1 No. 1 Hitachi Ltd. Hitachi factory

Claims (6)

[Claims] 1. In order to keep spent fuel generated in a nuclear power plant in a spent fuel pool at a predetermined interval and to keep it aligned in an upright state, the corner wall thickness constitutes a rectangular tubular body. A plurality of rectangular cylinders having corner portions with a radius of curvature substantially equal to the wall thickness are provided, and the distance between the outer wall surfaces of the square cylinder is substantially equal to the distance between the inner wall surfaces of the square cylinder. The checkerboard pattern is arranged in such a manner that a joining member having a notch in a part of its longitudinal direction is inserted and interposed between the corners of the rectangular tubular body, and the weld metal is welded to the notch. In a spent fuel storage rack in which the square tubular bodies are fixed to each other by filling the square tubular body with a mountain shape so that the cross-sectional shape of the bottom of the notch of the joining member is an equilateral triangle. A featured spent fuel storage rack. 2. The spent fuel storage rack according to claim 1, wherein the cross-section of the bottom of the cutout portion of the joining member is trapezoidal. 3. The spent fuel storage rack according to claim 1, wherein the joining member is made of stainless steel. 4. The spent fuel storage rack according to claim 1, wherein the joining member is made of cast stainless steel. 5. The spent fuel storage rack according to claim 1, wherein the joining member is made of ceramics. 6. The B or G element according to claim 1, wherein the joining member is an element having a high neutron absorbing ability.
d, Sm, Eu, Cd, Dy, In, Er, Ta, R
A spent fuel storage rack made of a material containing any one or more elements such as h, Tm, Lu, Hf, Au, Re and Ag.