JP2664820B2 - Jig for confirming the attachment of fuel assembly members - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a jig for checking the attachment of a fuel assembly member such as a channel box and a channel fastener to be installed outside a fuel bundle.

[0002]

2. Description of the Related Art A fuel assembly used in a boiling water reactor has a polygonal cylindrical channel box mounted outside a fuel bundle. The channel box serves as a guide for a control rod inserted between the fuel assemblies, while securing a flow path of the cooling water flowing through the fuel assemblies.

[0003] Further, since it is intended to be a strength member of the fuel assembly itself, it is necessary to surely mount the fuel assembly to the fuel assembly. Therefore, the channel box is fixed to the fuel bundle by screwing the channel fastener after fitting the channel box to the outside of the fuel bundle.

[0004] As a method of confirming the mountability of the channel box to the fuel assembly, there is a method of mounting the channel box to the fuel assembly before the fuel assembly is used in the nuclear reactor. Since it has only a small amount of radioactivity, the mounting of the channel box and the fixing of the channel fastener can be easily performed in the air, and the mounting properties can be closely checked visually.

At present, as shown in FIG. 5, a fuel assembly used in a boiling water reactor includes a large number of fuel rods 1 containing uranium fuel therein, and an upper tie plate 2,
A polygonal channel box 5 is fitted to the outside of a fuel bundle bundled in a polygonal shape by a lower tie plate 3 and a number of spacers 4, and the channel box 5 and the fuel bundle are fixed by a channel fastener 6.

FIG. 6 is an enlarged view of a portion where the fuel bundle, the channel box 5 and the channel fastener 6 are connected. In the fuel assembly, a screw hole 7a is cut at one upper portion of a corner post 7 located at four corners of the upper tie plate 2.

A triangular plate called a clip 8 for fixing the fuel bundle to the fuel bundle is welded to the upper corner of the channel box 5.
A through-hole 8a for passing through is provided. On the other hand, since the channel fastener 6 is a kind of screw, the channel fastener 6 can be fixed to the fuel bundle by passing the channel fastener 6 through the through hole 8a of the clip 8 of the channel box 5 and screwing it into the screw hole 7a. .

[0008]

As described above, the mounting of the channel box and the fixing of the channel fastener can be easily carried out in the air, and the mounting properties can be closely checked visually. However, once the channel box is removed and reinstalled after the fuel assembly has been used in a nuclear reactor for inspection or the like, the fuel assembly and the channel box have strong radioactivity.

For this reason, the channel box is fitted to the fuel bundle by remote control in water, and the subsequent channel fastener is attached. Therefore,
When the channel box is mounted by remote control in the water, the checking of the mounting property is only a visual inspection from above the water, and there is a problem that is not sufficient.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problem, and it is not necessary to visually check from above the water when checking the mounting property when the channel box is mounted by remote control in water. Another object of the present invention is to provide a jig for confirming the attachment of a fuel assembly member, which can be confirmed by measuring the distance between the channel box and the fuel bundle and the distance between the channel box and the channel fastener.

[0011]

SUMMARY OF THE INVENTION According to the present invention, a first and second inner cylinders, which are concentrically elongated, are elastically inserted into a long outer cylinder having a projection at the lower end. A measurement arm of a channel grip is connected to a lower portion of the first inner cylinder,
A measurement arm of a channel fastener head is connected to a lower part of the second inner cylinder, a first lock piece and a first dimension indicating needle are provided at an upper part of the first inner cylinder, and the second A second lock piece and a second dimension indicating needle are provided on the upper part of the inner cylinder, and the outer cylinder and the inner cylinder corresponding to the first and second lock pieces and the first and second pointers are provided. It is characterized in that a locking slit and an indicating scale are provided.

[0012]

The present invention is intended to measure the distance between the base of the upper tie plate and the lower surface of the channel clip when checking the mountability of the channel box. It can be confirmed numerically. In addition, to confirm the attachment of the channel fastener, the distance between the upper surface of the channel fastener head and the lower surface of the channel clip is checked.

That is, in the prior art, the fitting of the fuel assembly members, such as the channel box and the channel fasteners, which were installed underwater and re-mounted, was confirmed only by visual observation. However, according to the present invention, the fitting can be quantitatively and reliably confirmed. .

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of a jig for checking the attachment of a channel box according to the present invention will be described with reference to FIG.
In FIG. 1, the same parts as those in FIGS. 5 and 6 are denoted by the same reference numerals and described. In FIG. 1, upper tie plate 2
Of the triangular plate-shaped clip 8 provided horizontally on the upper end surface of the channel box 5 is measured. Further, the distance (B) between the lower surface of the clip 8 and the head 10 of the channel fastener is measured.

As a reason for measuring the distance (A) between the lower surface of the clip 8 and the base portion 9 of the upper tie plate, the channel box 5 is fitted outside the fuel bundle and the upper surface of the corner post 7 of the upper tie plate 2 is measured. Due to the structure in contact with the upper side, measuring the distance between the lower surface of the clip 8 of the channel box 5 and the upper tie plate 2 is the best method for confirming the mounting property.

Since the dimensional tolerance of the corner post 7 at the time of manufacturing the upper tie plate is taken from the base 9 shown in the figure, the distance between the lower surface of the clip 8 and the base 9 of the upper tie plate 2 is obtained. In the measurement of (A), the measurement error is only the dimensional tolerance of the corner post 7.

On the other hand, when measuring the distance between the other portion of the upper tie plate 2, for example, the upper surface of the handle 11 of the upper tie plate 2 shown in FIG. Overlap, and the measurement error increases.

The lower surface of the clip 8 and the channel fastener 6
The reason why the distance (B) between the upper surface of the head 10 and the lower surface of the clip 8 is measured is the same as the reason why the distance (A) between the lower surface of the clip 8 and the base 9 of the upper tie plate is measured.

In the measurement of the distance (B) between the lower surface of the clip 8 and the upper surface of the head 10, the manufacturing tolerance that causes a measurement error is the clip 8.
, The thickness tolerance of the spring washer 12 of the channel fastener 6 and the tolerance of the head 10 of the channel fastener 6, but other portions of the upper tie plate 2, for example, the upper surface of the handle 11 of the upper tie plate 2. When measuring the distance between, for example, the top surface of the channel fastener head 10 and the like, the manufacturing tolerances of other parts overlap, and the measurement error increases.

Therefore, in order to confirm that the channel box 5 is securely attached to the fuel bundle and that the channel fastener 6 is securely fixed, the lower surface of the clip 8 and the base 9 of the upper tie plate 2 must be connected. (A) and the lower surface of the clip 8 and the channel fastener 6
Measuring the distance (B) to the top surface of the head 10 can reduce measurement errors due to manufacturing tolerances most.

FIG. 2 is a block diagram showing a jig for confirming the mountability of the fuel assembly member in the first embodiment. The embodiment of the jig for confirming the mountability will be described with reference to FIG. In FIG. 2, reference numeral 20 denotes a long outer cylinder into which a first inner cylinder 22 and a second inner cylinder 23 are inserted concentrically. Outer cylinder
Spacer 19 for maintaining a gap between 20 and first inner cylinder 22
Are provided on the outer surface of the first inner cylinder 22. The lower end of the outer cylinder 20 is closed by a lower end plug 18, and a projection is formed on the lower surface of the lower end plug 18.
21 are attached. The protrusion 21 is inserted into a cooling water passage hole 9a provided in the base portion 9 of the upper tie plate 2. An upper end of the outer cylinder 20 is connected to an annular upper end plug 17.

A broken line is formed on the peripheral surface of the outer cylinder 20 below the upper end plug 17.
A first free and locking notch slit 15 as shown only partially on one side and shown at 16, and a first scale slit 13 as partially drawn out and only shown on the other side at a broken line 14, as shown in FIG. Are formed. First scale slit 13
The scale (mm) is engraved on the outside of.

The first inner cylinder 22 has a first scale slit 13.
A first dimension indicating needle 26 and a first lock piece 28 respectively inserted into the first free and lock slits 15 are attached so as to face each other. Also the first
A through hole 40 through which the upper surface measurement arm 25 penetrates is formed above the lower surface measurement arm 24 attached to the lower side surface of the inner cylinder 22.

A first slit 30 and a second slit 31 for penetrating the lower surface and upper surface measurement arms 24 and 25 are formed in the lower peripheral surface of the outer cylinder 20 in the vertical direction. The lower slit measuring arm 24 of the channel clip attached to the lower part of the first inner cylinder 22 is inserted into the first slit 30, and the lower slit is attached to the lower part of the second inner cylinder 23 in the second slit 31. The arm 25 for measuring the upper surface of the head of the channel fastener is inserted.

The upper end of the first inner cylinder 22 is closed by an upper end plate 32, and the upper peripheral surface of the first inner cylinder 22 is partially drawn out by a broken line 33, as shown only on one side, as shown in FIG. 2 and a third slit 34 for free and lock, and a second scale slit 36 as partially drawn out by a broken line 35 and shown only on the other side.
Are formed. A scale (mm) is engraved outside the second scale slit 36.

In the upper part of the second inner cylinder 23, the second dimension indicating needle and the second lock piece 29 are opposed to the second scale slit 36 and the second free and lock slits 34, respectively. Is attached. A small-diameter spring 37 is inserted between the upper end surface of the second inner cylinder 23 and the upper end plate 32, and a large-diameter spring 38 is inserted between the lower end surface of the first inner cylinder 22 and the lower end plug 18. I have.

Next, a description will be given of a method for using the jig having the above-mentioned structure. First, the jig is suspended from above the water above the fuel assembly on which the channel box 5 and the channel fastener 6 are mounted, and the projection 21 at the lower end of the jig is inserted into the cooling water flow passage hole 9 a in the base 9 of the upper tie plate 2. . At this time, the first inner cylinder 22 and the second inner cylinder 23 are each fixed at the locked position.

Next, by setting the lock piece 28 of the first inner cylinder 22 to the free position from the locked position, the arm 24 for measuring the lower surface of the channel clip by the force of the large-diameter spring 38 installed at the lower portion. Is lifted, and the arm 24 for measuring the lower surface of the channel clip contacts the lower surface of the channel clip 8.

The measured value of the dimension at this time is displayed on the first dimension indicating needle 26.
To obtain the distance (A) between the lower surface of the clip 8 of the channel box 2 and the base 9 of the upper tie plate 2 of the fuel assembly. In this case, the reference surface for dimension measurement is the surface provided with the projection 21 at the lower end of the jig, that is, the upper tie plate base 9.

Next, by setting the second lock piece 29 of the second inner cylinder 23 from the locked position to the free position, the head of the channel fastener 6 is moved by the force of the small-diameter spring 37 installed above. The upper surface measurement arm 25 of the channel fastener 6 is pushed down, and the upper surface measurement arm of the head 10 of the channel fastener 6 is pressed.
25 contacts the top surface of the head 10 of the channel fastener.

At this time, the measured dimension value is read from the dimension indicating needle 27 to obtain a distance (B) between the lower surface of the channel clip 8 and the upper surface of the head portion 10 of the channel fastener 6. In this case, the reference surface for dimension measurement is the upper surface of the arm 24 for measuring the lower surface of the channel clip 8, that is, the lower surface of the channel clip 8.

Next, a second embodiment of the present invention will be described with reference to FIG. In the second embodiment, as shown in FIG. 3, the distance (A) between the lower surface of the clip 8 and the base 9 of the upper tie plate and the upper surface of the head 10 of the channel fastener 6 and the base of the upper tie plate 2 Measuring the distance (C) to the distance 9 can reduce measurement errors due to manufacturing tolerances.

As a reason for measuring the distance (A) between the lower surface of the clip 8 and the base 9 of the upper tie plate, the channel box 5 is fitted on the outside of the fuel bundle and the upper surface of the corner post 7 of the upper tie plate and Due to the contact structure, measuring the distance between the lower surface of the clip 8 of the channel box 5 and the upper tie plate 2 is the best method for confirming the mounting property.

Here, since the dimensional tolerance of the corner post 7 at the time of manufacturing the upper tie plate is taken from the base 9 shown in the figure, the lower surface of the clip 8 of the channel box and the base 9 of the upper tie plate are formed. In the measurement of the distance (A), the measurement error is only the dimensional tolerance of the corner post 7.

On the other hand, when the distance between the other portion of the upper tie plate, for example, the upper surface of the handle 11 of the upper tie plate, and the lower surface of the clip 8 of the channel box is measured, the manufacturing tolerance of the other portion overlaps and the measurement is performed. The error will increase.

The reason why the distance (C) between the upper surface of the head portion 10 of the channel fastener and the base portion 9 of the upper tie plate is measured is that the lower surface of the clip 8 of the channel box 5 and the base portion 9 of the upper tie plate Is the same as the reason for measuring the distance (A).

In the measurement of the distance (C) between the upper surface of the head portion 10 of the channel fastener and the base portion 9 of the upper tie plate, the manufacturing tolerance which causes a measurement error includes the dimensional tolerance of the corner post 7 at the time of manufacturing the upper tie plate and the channel. Only the thickness tolerance of the clip 8 of the box, the thickness tolerance of the spring washer 12 of the channel fastener 6 and the tolerance of the head 10 of the channel fastener.

When the distance between another portion of the upper tie plate, for example, the upper surface of the handle 11 of the upper tie plate, and the upper surface of the head portion 10 of the channel fastener is measured, the manufacturing tolerance of the other portion overlaps, and a measurement error occurs. Will expand.

Therefore, in order to confirm that the channel box 5 is securely attached to the fuel bundle and that the channel fastener 6 is securely fixed, the lower surface of the clip 8 of the channel box and the base of the upper tie plate are required. Measuring the distance (A) to the base 9 of the channel fastener and the distance (C) between the upper surface of the head 10 of the channel fastener and the base 9 of the upper tie plate are methods that can reduce measurement errors due to manufacturing tolerances.

FIG. 4 shows a jig for confirming the mounting property of the channel box using this measuring method. The jig measures the distance between the lower surface of the clip 8 of the channel box and the base 9 of the upper tie plate of the fuel assembly, and measures the distance between the upper surface of the head 10 of the channel fastener and the base of the upper tie plate of the fuel assembly. A jig for measuring the distance C to the part 9;
The same parts as those shown in FIG. 2 are denoted by the same reference numerals, and the description of the overlapping parts will be omitted.

In this embodiment, a short large-diameter outer cylinder 39 closed by an upper end plate 41 is connected to the upper end of the outer cylinder 20.
The second slit 34 and the second scale slit
The other parts are the same as those in the first embodiment. A short large-diameter spring 42 is interposed between the lower surface of the upper end plate 41 and the upper end of the second inner cylinder 23.

The method of using this jig is almost the same as the method described in the first embodiment. That is, first, the jig is suspended from above the water above the fuel assembly in which the channel box 5 and the channel fastener 6 are mounted, and the projection 21 at the lower end of the jig is fixed to the cooling water passage hole 9 in the base 9 of the upper tie plate.
a. At this time, the first inner cylinder 22 and the second inner cylinder
23 is fixed in the position of each lock.

Next, by setting the first lock piece 28 of the first inner cylinder 22 from the locked position to the free position, the elastic force of the large-diameter spring 38 provided at the lower portion causes the channel clip 8 to move. Is lifted, and the arm 24 for measuring the lower surface of the channel clip contacts the lower surface of the channel clip 8.

The measured value of the dimension at this time is displayed on the first dimension indicating needle 26.
And the distance between the lower surface of the clip 8 of the channel box and the base 9 of the upper tie plate of the fuel assembly (A)
Get. In this case, the reference surface for dimension measurement is a surface on which the projection 21 at the lower end of the jig is provided, that is, the upper tie plate base 9.
It is.

Next, the lock 29 of the inner cylinder 23 is moved from the locked position to the free position, so that the elastic force of the short large-diameter spring 42 installed on the upper portion allows the upper surface of the head 10 of the channel fastener 6 to be moved. The measurement arm 25 is pushed down, and the upper surface measurement arm 25 of the head of the channel fastener 6 contacts the upper surface of the head 10 of the channel fastener.

The measured value of the dimension at this time is displayed on the second dimension indicating needle 27.
And the distance between the upper surface of the head 10 of the channel fastener 6 and the base 9 of the upper tie plate of the fuel assembly (C)
Get. In this case, the reference surface for dimension measurement is the protrusion at the lower end of the jig.
The surface provided with 21, that is, the upper tie plate base 9.

In the present invention, an example is shown in which a dimension indicating needle is used to obtain a dimension measurement result. However, in order to improve the accuracy of a measuring jig, instead of installing the dimension indicating needle on the water surface, each dimension indicating needle is used. An operation transformer or the like may be installed near the measurement arm and digitally displayed by a signal obtained from the operation transformer or the like.

[0048]

According to the present invention, it is possible to numerically confirm that the wearability is insufficient. Therefore, it is possible to prevent the channel fastener from dropping during the operation of the reactor, which is expected to occur in the worst case, and prevent the coolant from leaking out of the channel due to improper installation of the channel box.

[Brief description of the drawings]

FIG. 1 is a vertical cross-sectional view for explaining a checking method in a first embodiment of a jig for checking mounting of a fuel assembly member according to the present invention.

FIG. 2 is a configuration diagram showing a first embodiment of a jig for confirming mountability of a fuel assembly member according to FIG. 1;

FIG. 3 is a vertical cross-sectional view for explaining a checking method in a second embodiment of a jig for checking the mounting property of a fuel assembly member according to the present invention.

FIG. 4 is a configuration diagram showing a second embodiment of the jig for checking the attachment of the fuel assembly member according to FIG. 3;

FIG. 5 is a partially cutaway perspective view for explaining a mounting state of a channel box to a fuel assembly for a boiling water reactor.

FIG. 6 is an enlarged longitudinal sectional view showing a main part in FIG. 5;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Fuel rod, 2 ... Upper tie plate, 3 ... Lower tie plate, 4 ... Spacer, 5 ... Channel box, 6 ... Channel fastener, 7 ... Corner post, 8 ... Channel clip, 9 ... Base, 10 ... Head , 11 ... handle, 12
... Spring washers, 13 ... First scale slits, 14, 16 ... Dashed lines, 15 ... First free and locking slits, 17 ... Top stopper, 18 ... Bottom stopper, 19 ... Spacer, 20 ... Outer cylinder, 21 ... Protrusion at the tip, 22 ... First inner cylinder, 23 ... Second inner cylinder, 24 ... Bottom measurement arm, 25 ... Top measurement arm, 26 ... First dimension indicating needle, 27 ... Second dimension Pointer, 28 ... first lock piece, 29
... second lock piece, 30 ... first slit, 31 ... second slit, 32 ... top plate, 33 ... dashed line, 34 ... second slit,
35 ... broken line, 36 ... second scale slit, 37 ... small diameter spring, 38 ... large diameter spring, 39 ... short large diameter outer cylinder, 40 ... through hole.

 ──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Yutaka Hirose 66-2 Horikawa-cho, Sai-ku, Kawasaki-shi, Kanagawa Prefecture Toshiba Engineering Corporation (56) References JP-A-5-27081

Claims (1)

(57) [Claims] 1. An elongate outer cylinder having a projection at the lower end.
The first inner cylinder and the second inner cylinder which are long in a center circle are elastically
A channel grip is inserted and attached to a lower portion of the first inner cylinder.
Is connected to the lower arm of the second inner cylinder.
The measurement arm of the channel fastener head is connected,
A first lock piece and a first dimension finger are provided on an upper portion of the first inner cylinder.
A pointer is provided, and a second lock is provided on an upper portion of the second inner cylinder.
A piece and a second dimension indicating needle are provided, wherein the first and second dimension indicating needles are provided.
A second lock piece corresponds to the first and second pointers.
Locking slits and indicator
A fuel assembly member characterized by being provided with a heap
A jig for checking wearability.