JPH0534492A - Installation verification of fuel assembly member and jig therefor - Google Patents

Abstract

PURPOSE:To ensure verification of installations of a channel box and a channel fastener to a fuel bundle for a fuel assembly after irradiation, which are carried out in a remote submarine mode, where verification of installation is difficult. CONSTITUTION:A distance A between a base part 9 of an upper tie plate 2 and a lower surface of a channel clip 8 is measured for verification of installation of a channel box. A distance B between the lower surface of the clip 8 and a head part 10 of a channel fastener 6 is measured for verification of installation of the channel fastener. A deviation in measurement can be reduced by measuring the distances A and B. Film separation between the base part 9 and the head part 10 of the channel fastener 6 can also be measured instead of the distance B.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for checking the mountability of a fuel assembly member such as a channel box and a channel fastener mounted on the outside of a fuel bundle, and a jig therefor.

[0002]

2. Description of the Related Art In a fuel assembly used in a boiling water reactor, a polygonal tubular channel box is mounted outside a fuel bundle. This channel box is intended to secure a flow path for cooling water flowing through the fuel assemblies, serve as guides for control rods inserted between the fuel assemblies, and serve as a strength member for the fuel assemblies themselves. Therefore, it is necessary to reliably mount the fuel assembly.
Therefore, the channel box is fixed to the fuel bundle by screwing the channel fastener after fitting the channel box on the outside of the fuel bundle.

As a method for confirming the mountability of the channel box to the fuel assembly, when the channel box is mounted to the fuel assembly before the fuel assembly is used in the reactor, the fuel assembly is Since it has only a small amount of radioactivity, it is easy to attach the channel box and fix the channel fasteners in the air, and the attachability can be visually confirmed in close proximity.

As shown in FIG. 5, a fuel assembly currently used in a boiling water reactor has a large number of fuel rods 1 containing uranium fuel therein, an upper tie plate 2,
A polygonal channel box 5 is fitted on the outside of a fuel bundle bundled in a polygonal shape by a lower tie plate 3 and a large 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 in engagement with each other. In the fuel assembly, screw holes 7a are formed at the upper portions of the corner posts 7 located at the four corners of the upper tie plate 2. Further, a triangular plate called a clip 8 for fixing to the fuel bundle is welded to the upper corner of the channel box 5, and a through hole 8a for allowing the channel fastener 6 to pass through is formed. On the other hand, since the channel fastener 6 is a kind of screw, the channel box 6 and the fuel bundle can be fixed 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. .

[0006]

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 ability can be visually checked closely. However, if the channel box is once removed and then reattached for inspection of the fuel assembly after being used even once in the nuclear reactor, the fuel assembly and the channel box have strong radioactivity.
Therefore, the channel box is fitted to the fuel bundle by remote control in water, and then the channel fastener is attached. Therefore, when the channel box is attached by remote control in water, the confirmation of the mountability is only a visual inspection from above the water, which is not sufficient.

The present invention has been made in order to solve the above-mentioned problems, and when confirming the mountability when the channel box is attached by remote control underwater, it is not visually performed from above the water. An object of the present invention is to provide a mountability confirmation method performed by measuring the distance between the channel box and the fuel bundle and the channel box and the channel fastener, and a mountability confirmation jig for a fuel assembly member using the mountability confirmation method.

[0008]

According to a first aspect of the present invention, a polygonal tubular channel box mounted outside a fuel assembly for a boiling water nuclear reactor is mounted on the fuel assembly, and a channel fastener is provided. In a method of confirming the attachment of a channel box for confirming that the channel box is fixed to a fuel assembly, a distance between a clip of the channel box and a base portion of the upper tie plate of the fuel assembly, a clip of the channel box and the channel fastener. Or the distance between the channel box clip and the base of the fuel assembly upper tie plate and the distance between the channel box head and the base of the fuel assembly upper tie plate. It is characterized by

According to a second aspect of the present invention, the first inner cylinder and the second inner cylinder which are concentrically elongated are elastically inserted into an elongated outer cylinder having a protrusion at a lower end thereof, and the first inner cylinder is elastically attached. A channel grip measuring arm is connected to the lower part of the inner cylinder of the channel fastener, a measuring arm of the channel fastener head is connected to the lower part of the second inner cylinder, and a first lock is connected to the upper part of the first inner cylinder. A piece and a first dimension indicating needle, and a second lock piece and a second dimension indicating needle on the upper part of the second inner cylinder, and the first and second lock pieces and the first Further, the outer cylinder and the inner cylinder corresponding to the second indicating needle are provided with a lock slit and an indicating scale.

[0010]

According to the first aspect of the present invention, when confirming the mountability of the channel box, the distance between the base of the upper tie plate and the lower surface of the channel clip is measured. To confirm the fit of the channel fastener, measure the distance between the upper surface of the channel fastener head and the lower surface of the channel clip. Measuring these distances is most likely to reduce measurement error due to manufacturing tolerances.

The second invention is for measuring the distance in the first invention, and by measuring the distance, it is possible to numerically confirm the insufficient wearability. That is, in the conventional example, the mountability of the fuel assembly members such as the channel box and the channel fasteners remounted in the water was confirmed only by visual inspection, but the mountability can be reliably confirmed quantitatively by the second invention.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of a method for confirming the mountability 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 designated by the same reference numerals for description. In FIG. 1, the upper tie plate 2
The distance (A) between the base 9 and the lower surface of the triangular plate-shaped clip 8 horizontally provided 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 portion 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. Since the structure is in contact with, the measurement of 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 mountability. Here, since the dimensional tolerance of the corner post 7 at the time of manufacturing the upper tie plate is taken from the base portion 9 shown in the drawing, the distance (A) between the lower surface of the clip 8 and the base portion 9 of the upper tie plate 2 (A). In the measurement of, the measurement error is only the dimensional tolerance of the corner post 7. On the other hand, other parts of the upper tie plate 2, for example, FIG.
The upper surface of the handle 11 of the upper tie plate 2 shown in
When the distance from the lower surface of the clip 8 is measured, the manufacturing tolerances of other parts are overlapped with each other and the measurement error is increased.

The lower surface of the clip 8 and the channel fastener 6
The reason for measuring the distance (B) from the upper surface of the head 10 is the same as the reason for measuring the distance (A) between the lower surface of the clip 8 and the base portion 9 of the upper tie plate. In the measurement of the distance (B) from the upper surface of the portion 10, the manufacturing tolerances that cause measurement errors are only the thickness tolerance of the clip 8, the thickness tolerance of the spring washer 12 of the channel fastener 6 and the tolerance of the head portion 10 of the channel fastener 6. However, when the distance between the other part of the upper tie plate 2 such as the upper surface of the handle 11 of the upper tie plate 2 and the upper surface of the head part 10 of the channel fastener is measured, manufacturing tolerances of other parts are overlapped, The measurement error will increase.

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 portion 9 of the upper tie plate 2 are to be confirmed. Distance (A) and the underside of the clip 8 and the channel fastener 6
Measuring the distance (B) from the upper surface of the head 10 can most reduce the measurement error due to manufacturing tolerances.

FIG. 2 is a block diagram showing a mountability confirmation jig for the fuel assembly member in the first embodiment. An embodiment of the mountability confirmation jig will be described with reference to FIG. In FIG. 2, reference numeral 20 is a long outer cylinder, and a first inner cylinder 22 and a second inner cylinder 23 are concentrically inserted in the outer cylinder 20. Outer cylinder
Spacer 19 for maintaining a gap between 20 and the first inner cylinder 22
Is 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 the lower surface of the lower end plug 18 has a protrusion.
21 is attached. The protrusion 21 is to be inserted into the cooling water passage hole 9a provided in the base portion 9 of the upper tie plate 2. An annular upper end plug 17 is connected to the upper end of the outer cylinder 20. The outer cylinder 20 below the upper end plug 17 is partially drawn out with a broken line 16 on the peripheral surface thereof and is cut out with a first notch slit 15 for free and lock as shown only on one side, and partially drawn out with a broken line 14. As shown on the other side only, the first scale slit
And 13 are formed. A scale (mm) is engraved on the outside of the first scale slit 13. The first inner cylinder 22 has a first dimensional indicator needle inserted into the first graduation slit 13 and the first free and lock slit 15, respectively.
26 and the first lock piece 28 are attached so as to face each other. Further, a through hole 40 through which the upper surface measuring arm 25 penetrates is formed above the lower surface measuring arm 24 attached to the lower side surface of the first inner cylinder 22. A first slit 30 and a second slit 31 for penetrating the lower surface and the upper surface measuring arms 24 and 25 are formed on the lower peripheral surface of the outer cylinder 20 in the vertical direction. The first inner cylinder 22 is provided in the first slit 30.
The lower surface measurement arm 24 of the attached channel clip is inserted into the lower part of the second inner cylinder 23 of the second slit 31.
An upper surface measuring arm 25 of the head portion of the channel fastener attached to the lower part of 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 with a broken line 33 to show only one side surface. The second free and lock third slit 34, and the second scale slit 36 as shown only on the other side by partially drawing out with a broken line 35.
And are formed. A scale (mm) is engraved on the outside of the second scale slit 36. At the upper part of the second inner cylinder 23, a second scale slit 36 and a second free and lock slit 34 are provided so as to face each other.
Dimension indicating needle and the second lock piece 29 are 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. There is.

Next, a method of using the mountability confirmation jig having the above structure will be described. First, the jig is suspended above the water above the fuel assembly in which the channel box 5 and the channel fastener 6 are mounted, and the protrusion 21 at the lower end of the jig is inserted into the cooling water passage hole 9a of the base portion 9 of the upper tie plate 2. . At this time, the first inner cylinder 22 and the second inner cylinder 23 are fixed at the lock positions. Next, the lock piece of the first inner cylinder 22
By moving 28 from the locked position to the free position,
The lower surface measurement arm 24 of the channel clip is lifted by the force of the large-diameter spring 38 installed at the lower part, and the lower surface measurement arm 24 of the channel clip contacts the lower surface of the channel clip 8. The dimension measurement value at this time is read from the first dimension indicating needle 26, and the distance (A) between the lower surface of the clip 8 of the channel box 2 and the base portion 9 of the upper tie plate 2 of the fuel assembly is obtained. The reference surface for dimension measurement in this case is the surface provided with the protrusion 21 at the lower end of the jig, that is, the upper tie plate base portion 9.

Next, by moving 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 driven by the force of the small diameter spring 37 installed at the upper part. The upper surface measurement arm 25 of 10 is pushed down, and the upper surface measurement arm of the head 10 of the channel fastener 6 is pressed.
25 contacts the upper surface of the head 10 of the channel fastener. The dimension measurement value at this time is read from the dimension indicating needle 27 to obtain the distance (B) between the lower surface of the channel clip 8 and the upper surface of the head 10 of the channel fastener 6. The reference surface for dimension measurement in this case is the upper surface of the lower surface measurement arm 24 of the channel clip 8, that is, the lower surface of the channel clip 8.

Next, a second embodiment of the method 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 portion 9 of the upper tie plate and the head portion 10 of the channel fastener 6.
Between the upper surface of the base and the base 9 of the upper tie plate 2 (C)
Is a way to reduce measurement error due to manufacturing tolerances.

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 to the outside of the fuel bundle and the upper surface of the corner post 7 of the upper tie plate. Because of 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 mountability. Here, since the dimensional tolerance of the corner post 7 at the time of manufacturing the upper tie plate is taken from the base portion 9 shown in the figure, the distance between the lower surface of the clip 8 of the channel box and the base portion 9 of the upper tie plate. In the measurement of (A), the measurement error is only the dimensional tolerance of the corner post 7. On the other hand, when the distance between the other part 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 tolerances of the other parts overlap and the measurement error increases. Will be done.

The reason for measuring the distance (C) between the upper surface of the head 10 of the channel fastener and the base portion 9 of the upper tie plate is that the lower surface of the clip 8 of the channel box 5 and the base portion 9 of the upper tie plate are Is the same as the reason for measuring the distance (A), and the manufacturing tolerance that causes a measurement error in the measurement of the distance (C) between the upper surface of the head 10 of the channel fastener and the base 9 of the upper tie plate is the upper tie plate. Only the dimensional tolerance of the corner post 7 at the time of manufacture, the plate thickness tolerance of the clip 8 of the channel box, the plate thickness tolerance of the spring washer 12 of the channel fastener 6 and the tolerance of the channel fastener head 10 are used. When measuring the distance between the upper portion of the channel fastener, such as 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, the manufacturing tolerances of other portions may be overlapped. , So that the measurement error is enlarged.

Therefore, in order to confirm that the channel box 5 is securely attached to the fuel bundle and the channel fastener 6 is securely fixed, the lower surface of the clip 8 of the channel box and the base portion of the upper tie plate are confirmed. Measuring the distance (A) from the channel fastener 9 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 is a method that can reduce the measurement error due to manufacturing tolerances.

FIG. 4 shows a jig for confirming the mountability of a channel box using this measuring method. This jig measures the distance between the lower surface of the clip 8 of the channel box and the base portion 9 of the upper tie plate of the fuel assembly, and the upper surface of the head 10 of the channel fastener and the base of the upper tie plate of the fuel assembly. The jig is a jig that can measure the distance to the part 9, and the same parts as those shown in FIG.

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 graduation slit on the peripheral surface of
Since 36 is provided, other parts are the same as in the first embodiment. A short large-diameter spring 42 is inserted 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 FIG. 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 provided in the cooling water passage hole 9a of the base portion 9 of the upper tie plate. Plug in. At this time, the first inner cylinder 22 and the second inner cylinder 23 are fixed at their respective lock positions. Next, the first inner cylinder
By moving the first lock piece 28 of 22 from the locked position to the free position, the elastic force of the large-diameter spring 38 installed at the lower part allows the lower surface measurement arm of the channel clip 8 to be measured.
24 is lifted, and the lower surface measurement arm 24 of the channel clip contacts the lower surface of the channel clip 8. The dimension measurement value at this time is read from the first dimension indicating needle 26, and the distance (A) between the lower surface of the clip 8 of the channel box and the base portion 9 of the upper tie plate of the fuel assembly is obtained. The reference surface for dimension measurement in this case is the surface provided with the protrusion 21 at the lower end of the jig, that is, the upper tie plate base portion 9.

Next, the lock 29 of the inner cylinder 23 is moved from the locked position to the free position, so that the upper surface of the head 10 of the channel fastener 6 is repulsed by the elastic force of the short large-diameter spring 42 installed at the upper portion. The measurement arm 25 is pushed down, and the upper surface of the head of the channel fastener 6 contacts the upper surface of the head 10 of the channel fastener. The dimension measurement value at this time is read from the second dimension indicating needle 27, and the distance (C) between the upper surface of the head portion 10 of the channel fastener 6 and the base portion 9 of the upper tie plate of the fuel assembly is obtained. The reference surface for dimension measurement in this case is the surface provided with the protrusion 21 at the lower end of the jig, that is,
The upper tie plate base 9.

In the present invention, an example in which the dimension indicating needle is used to obtain the dimension measurement result is shown. However, in order to improve the accuracy of the measuring jig, the dimension indicating needle is not installed on the water surface but each It is also possible to install an operating transformer or the like near the measuring arm and digitally display the signal obtained from the operating transformer or the like.

[0029]

EFFECTS OF THE INVENTION According to the present invention, it is possible to numerically confirm the insufficient wearability. 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 excessive leakage of the cooling water to the outside of the channel due to improper mounting of the channel box.

[Brief description of drawings]

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

FIG. 2 is a configuration diagram showing a mountability confirmation jig for a fuel assembly member in FIG.

FIG. 3 is a vertical cross-sectional view for explaining a second embodiment of the method for confirming the mountability of the fuel assembly member according to the present invention.

FIG. 4 is a configuration diagram showing a mountability confirmation jig of a fuel assembly member in FIG.

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

FIG. 6 is an enlarged vertical sectional view showing a main part in FIG.

[Explanation 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 part, 10 ... Head part , 11 ... handle, 12
... Spring washers, 13 ... First scale slits, 14,16 ... Dashed lines, 15 ... First free and locking slits, 17 ... Top plugs, 18 ... Bottom plugs, 19 ... Spacers, 20 ... Outer cylinder, 21 ... tip projection, 22 ... first inner cylinder, 23 ... second inner cylinder, 24 ... lower surface measuring arm, 25 ... upper surface measuring arm, 26 ... first dimension indicating needle, 27 ... second dimension Indicator needle, 28 ... First lock piece, 29
... second lock piece, 30 ... first slit, 31 ... second slit, 32 ... upper plate, 33 ... broken line, 34 ... second slit,
35 ... Dashed line, 36 ... Second scale slit, 37 ... Small diameter spring, 28 ... Large diameter spring, 39 ... Short large diameter outer cylinder, 40 ... Through hole.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Yutaka Hirose             66-2 Horikawa-cho, Saiwai-ku, Kawasaki-shi, Kanagawa Prefecture             Engineering Co., Ltd.

Claims (2)

[Claims] 1. A polygonal tubular channel box mounted on the outside of a boiling water reactor fuel assembly is mounted on the fuel assembly, and a channel fastener is fixed to the fuel assembly. In the method of confirming the attachment of the channel box to be confirmed, the distance between the clip of the channel box and the base of the fuel assembly upper tie plate and the distance between the clip of the channel box and the head of the channel fastener, or the channel. Channel box wearability characterized by measuring the distance between the box clip and the base of the fuel assembly upper tie plate and the distance between the channel box head and the base of the fuel assembly upper tie plate. Confirmation method. 2. A first inner cylinder and a second inner cylinder which are concentrically elongated and are elastically inserted in a long outer cylinder having a protrusion at a lower end thereof, and the first inner cylinder is The measurement arm of the channel grip is connected to the lower part, the measurement arm of the channel fastener head is connected to the lower part of the second inner cylinder, and the first lock piece and the first lock piece are connected to the upper part of the first inner cylinder. Is provided, and a second lock piece and a second size indicating needle are provided on the upper part of the second inner cylinder, and the first and second lock pieces and the first and second lock pieces are provided. A jig for confirming the mountability of a fuel assembly member, wherein a lock slit and an indicator scale are provided on the outer cylinder and the inner cylinder corresponding to the indicating needle.