JPH0121475B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an assembly jig used when assembling a spacer for holding a large number of fuel elements in a fuel assembly for a nuclear reactor at intervals from each other in a channel. be.

(Prior art) A spacer for a BWR fuel body has a spacer 1 stretched over a plurality of dividers 2 arranged in a lattice pattern, a bar 3 and the outer periphery of these, as shown in FIG. 4 (a) and (b). Band 4 and box-shaped spring 5
The intersection of the divider 2 and the bar 3, the intersection of the divider 2, etc. are fixed by cross welding, and a fuel rod is inserted into each grid, and the spring It is designed to be held under pressure.

To manufacture this spacer 1, first, the divider, bar, and band are made by pressing from a Zircaloy 4 plate, and the box-shaped spring holding the fuel element is folded by pressing from an Inconel X750 plate. After curve forming, the overlapping parts are spot welded by resistance heating, and then
Manufactured by aging treatment, then washed and dried, assembled, welded divider intersections, divider and bar intersections, divider and band butts, and band connections, and finally washed and autoclaved. After processing, the spacer is completed, but as shown in FIG. 4, the fuel elements are spaced apart from each other, and a box-shaped spring that presses strongly in the radial direction of the fuel elements is attached to the intersection 16 of the bars.
It is placed in several places. This box-shaped spring is the fifth
As is clear from Figures A and B, the upper and lower horizontally long rectangular Incone Ru The parts are connected by thin leaf springs.

Therefore, this box-shaped spring 5 naturally has openings 5b in the upper and lower short cylindrical parts.

In this way, many box-shaped springs 5 are attached to the cross section of the bar 3 during assembly of the spacer, but as is clear from the above, the springs 5 are attached to the Inconel plate formed during the assembly. There is an overlapping portion 5a, and it is necessary to keep the direction of this overlapping portion constant in order to improve product quality and to always keep it regular and constant to standardize spacer products.

However, in the past, the work of assembling the springs to give them a certain directionality was done only by people visually referring to the drawings and assembling them while confirming that the drawings were correct. It was easy and lacked perfection.

(Problems to be Solved by the Invention) In view of the above-mentioned circumstances, the present invention aims to assemble the box-shaped springs in a regular and constant direction without making mistakes, and to assemble the spacer springs in a certain direction. The object of the present invention is to improve workability by providing a directional assembly jig that can be placed regularly and perfectly without errors.

(Means for Solving the Problems) The present invention, which solves the above-mentioned problems, is characterized by a main body portion that can be inserted into the opening of the square short tube portion of the box spring, and a It is a jig equipped with a head portion, and the main body portion has an outer dimension that is approximately the same as or slightly smaller than the inside dimension of the opening of the box-shaped spring, and has a relief corresponding to the overlapping portion of the spring at the outer tip. In addition, the head portion is provided with a positioning portion.

Here, the protrusion is the simplest positioning part for the head part, and it is easy to create a fitting relationship with the board used for assembling the spooter, but of course, other positioning parts other than the protrusion can be used. It is also quite possible to adopt this method.

Further, the material and formation of the main body portion and the head portion are not particularly limited, and shapes and materials that do not hinder assembly work may be used.

(Function) Therefore, the assembly jig according to the present invention is used in combination with upper and lower substrates prepared in advance, and first, the assembly jig of the present invention is arranged on the lower substrate with the box-shaped spring inserted into its opening. After that, dividers and bars are inserted into the grooves of the board as specified, and finally, the band is fitted into the grooves to assemble it in a lattice shape. However, this jig has an escape to receive the overlapping portion of the springs. Because of this, when the jig is inserted into the spring so that the overlapping part and the escape part match, the overlapping part will take one direction with respect to the positioning part of the jig.

In addition, when inserting into this lower board, in order to maintain a certain regularity within the lower board in the direction of the positioning part, make sure to position the lower board and the positioning part of this jig by ensuring that the protrusions and grooves are aligned with each other. It is necessary to position using means.

After the above operation, attach the upper board,
The springs can be regularly arranged in a certain direction by assembling the divider, welding the bar and the band abutting parts in a certain manner.

In addition, by freely changing the combination of the assembly jigs, it is possible to provide arbitrary regularity, and the range of use is diversified.

(Embodiments) Hereinafter, embodiments of the present invention will be described with further reference to the accompanying drawings.

1A, 1B, and 1C show an example of a positioning assembly jig according to the present invention, 11 is a head portion, 12 is a main body portion, and both are integrally formed. One positioning protrusion 13 is provided on its outer periphery. And, on the other hand,
In the illustrated example, a groove 15' into which the bar 3 to be assembled is inserted is carved in the main body portion 12 at its bottom, and an escape 17 is provided on the outer periphery to allow the overlapping portion 5a of the box-shaped springs to escape. is provided.

Figures 2 and 3 use the assembly jig as described above.
One mode of assembling a spacer is shown, and spacer 1
As shown in Figure 4, this fuel assembly is for an 8x8 BWR fuel assembly, and consists of 4 bands, 6 dividers, 16 pars, and 16 springs.

The procedure for assembling this spacer will be explained below with reference to FIGS. 1 to 3.

First, as shown in FIGS. 3A and 3B, two substrates A and B are prepared, each having a divider inserting groove 14, a bar inserting groove 15, and a band fitting groove 16, respectively. Among them, the prepared substrate A is used as a lower substrate, and the box-shaped spring 5 with the assembly jig main body part 12 of the present invention inserted into the short tube opening is arranged as shown in FIG. 2, and then the groove 14 A divider is then inserted into the groove 15, a bar is then inserted into the groove 15, and finally a band is fitted into the groove 16 to form a rectangular grid (8×8).

At this time, during the above assembly, in order to make the spring have a certain regular direction, the other end of the assembly jig according to the present invention, that is, the head portion 11 inserted into the spring, is inserted into the predetermined position a of the board A. However, since the assembly jig inserted into the board A needs to be positioned, after inserting the main body of the jig into the spring 5, the positioning part, that is, the protrusion provided on the head part 11 of the assembly jig, is inserted into the spring 5. Fitting the part 13 into the corresponding groove 18 of the substrate A,
Fit them together to ensure perfect positioning.

In this way, when the spring 5 is inserted and positioned at the required position a of the board A via the assembly jig, the grooves 14 for the divider, bar, and band are finally installed as in the other board A. 15,1
6 is placed on the top as shown in FIG. 2, the assembly position b is aligned, and the binder, bar, band mating portion, etc. are welded.

In this way, the BWR fuel spacer is completed.

(Effects of the Invention) As described above, the present invention includes a main body part that can be inserted into the opening of the short cylindrical part of a box-shaped spring, and a head part at the end of the main body part, which corresponds to the overlapping part of the spring. Since the relief is formed to correspond to the relevant position and a positioning part is provided on the head part, the spring is inserted into the outer periphery of the main body and the overlapping part of the spring matches the relief of the jig main body. By positioning the spacer and the substrate, the springs can be easily arranged in a regular direction without error, resulting in excellent workability, stabilizing the quality of the product spacer, and significantly improving the product value.

Moreover, by using the jig of the present invention, conventionally,
A spacer that eliminates errors and lack of regularity caused by people checking visually and assembling, and can give regularity in a certain direction, giving a directionality that freely incorporates the setting idea. It is possible to assemble it completely without any errors.

Furthermore, by inserting a spring into the jig of the present invention, it is possible to stably stand it upright.
This eliminates the problems of conventional bars and dividers that caused them to fall over when inserted, and has the advantage of making assembly operations even easier.

[Brief explanation of drawings]

1A, 2B, and 3 are side views, a top view, and a perspective view of an assembly jig that constitutes the essential parts of the present invention; FIG. 2 is a spring assembly state diagram using the above assembly jig; B is a partial plan view of an example of a board suitable for using the above assembly jig, and Figure 4 A and B are known BWRs.
FIGS. 5A and 5B are an enlarged plan view and a perspective view of the spring portion of FIG. 1; FIGS. 1... Spacer, 2... Divider, 3... Bar, 4... Band, 5... Spring, 5a...
Spring overlapping portion, 5b...Opening, 11...
...Jig head part, 12...Jig main body part, 13...
...Positioning part (protrusion), 17...Escape.

Claims (1)

[Scope of Claims] 1. A box-shaped spring in which a rectangular short cylindrical portion formed by bending upper and lower horizontally elongated rectangular plates, overlapping their ends, and fixing them together is connected by a narrow leaf spring on each side. A jig comprising a main body portion that can be inserted into the short cylindrical opening of the box spring, and a head portion at the end of the main body portion, the main body portion having an inner dimension approximately equal to the inner dimension of the short cylindrical opening of the box spring. have the same or slightly smaller outer dimensions and can be inserted into the inside of the spring;
An assembly jig for a spacer for a fuel body, characterized in that the jig has a relief corresponding to the overlapping portion of the spring at a predetermined position on its outer periphery, and a positioning portion is provided in the head portion. 2. The fuel assembly spacer assembly jig according to claim 1, wherein the positioning portion provided on the head portion of the jig is a protrusion. 3. Claim 1, wherein the jig main body has a groove at the bottom into which a bar constituting a spacer is inserted.
An assembly jig for a fuel assembly spacer according to item 1 or 2.