JP2000039493A - Narrow section pickup tool - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively recover a foreign matter or the like sandwiched between fuel rods in a short time. SOLUTION: The narrow part pick-up tool remotely recovers a foreign matter interposed between a plurality of fuel rods 2 under water. Here, a tool body 10 is moved and operated via an operating member at a predetermined position in a nuclear reactor. The body 10 has an engaging part 11 for engaging the member, a clipping implement 14 provided at the part 11 and inserted between a plurality of the rods 2 to clip the matter, and a driving means 18 for driving the implement 14.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for removing a fuel assembly from a reactor pressure vessel during a periodic inspection of a boiling water reactor and removing a plurality of fuel rods in a state where a channel box is removed from the fuel assembly. The present invention relates to a narrow portion pickup tool for collecting foreign matter intervening therebetween.

[0002]

2. Description of the Related Art In general, a plurality of fuel assemblies are loaded in a core of a boiling water reactor, and these fuel assemblies are formed in a rectangular cylindrical channel as shown in FIG. A plurality of fuel rods 2 are accommodated in a box 1, and the upper portions of the fuel rods 2 are supported by an upper tie plate 3, and the lower ends thereof are supported by a lower tie plate 4 shown in FIG. 9 is supported by the spacer 5. A plurality of fuel rods 2 are integrated by the upper tie plate 3, the lower tie plate 4, and the spacer 5 to constitute a fuel bundle 6 shown in FIG.

The lower end of the channel box 1 is pressed and supported by a flat spring 7 inserted into the lower tie plate 4. At the top four corners of the upper tie plate 3,
As shown in FIG. 12, posts 3a, 3b and 3c are provided. These posts 3a, 3b and 3c
It has a guide function when the channel box 1 is inserted into the bundle of fuel rods 2 from above.

The post 3b is in contact with a triangular stop member 8a fixed to the upper end of the channel box 1, and the post 3c is provided with a female screw 3d. As shown in FIG. The cap screw 9a is screwed to the upper tie plate 3 via a triangular stop member 8b fixed to the upper end of the channel box 1.

One channel fastener 9 is attached to one corner of the top of the fuel assembly, has a function of fixing the fuel bundle 6 and the channel box 1, and has a core (not shown) of a boiling water reactor. The fuel assemblies are pressed against each other by the springs 9b of the channel fasteners 9 so as to hold the fuel assemblies vertically and to have a space for inserting a control rod (not shown).
The upper tie plate 3 is provided with a handle 3e used when moving the fuel assembly.

Further, the channel fastener 9 is attached and detached in a water of a fuel pool (not shown) by a fuel attachment / detachment machine for inspection of a fuel assembly or the like. for that reason,
The components are not separated carelessly. FIG. 10 shows a state where the channel box 1 and the channel fastener 9 are removed.

[0007]

The fuel assembly constructed as described above is periodically replaced or inspected.
It is necessary to check the soundness. At the time of the periodic inspection, the fuel assembly is removed from the reactor pressure vessel, and the channel box 1 is removed from the fuel assembly.

When the fuel assembly expands in the axial direction of the fuel rod 2 caused by combustion in the nuclear reactor, and any foreign matter or the like stagnates between the fuel rods 2 due to vibration or cooling water, the fuel rod 2 is deformed. There is a possibility that the reactor may be damaged or damaged, and in this case, there is a problem that the sound operation of the reactor is hindered.

Conventionally, when foreign matter is interposed between the fuel rods 2, it has been attempted to remove the foreign matter by, for example, applying water pressure to the foreign matter, attaching a hook or the like to the tip of the operation pole, and hooking the foreign matter with the hook. However, these methods have a problem that it takes a long working time and it is difficult to reliably collect them.

The present invention has been made in view of the above circumstances, and has as its object to provide a narrow portion pickup tool capable of quickly and reliably recovering foreign matter or the like sandwiched between fuel rods.

[0011]

In order to solve the above-mentioned problems, a first aspect of the present invention is to remove a fuel assembly from a reactor pressure vessel during a periodic inspection of a reactor and to remove the fuel assembly from the fuel assembly. A narrow portion pickup tool for remotely collecting underwater foreign substances interposed between a plurality of fuel rods in a state where a channel box is removed, wherein a tool main body is moved and operated by an operation member to a predetermined position in the reactor,
The tool body includes an engagement portion with which the operation member is engaged,
It is characterized in that it is provided with a clipping tool provided in the engaging portion and inserted between the plurality of fuel rods to pinch foreign matter, and a driving means for driving the clipping tool.

According to the first aspect of the present invention, the tool body includes an engaging portion with which the operating member is engaged, a clipping tool provided in the engaging portion and inserted between a plurality of fuel rods to clamp foreign matter, With the provision of the driving means for driving the tool, foreign matter interposed between the fuel rods can be freely and remotely collected underwater and in a short time, and the working time can be greatly reduced.

According to a second aspect of the present invention, in the narrow-section pickup tool according to the first aspect, the holding member includes a fixed holding portion and a movable holding portion that is moved by the operation of the driving means and pressed against the fixed holding portion. It is characterized by having.

According to a third aspect of the present invention, in the narrow portion pickup tool according to the first or second aspect, a guide portion for guiding a moving direction of the movable holding portion is fixed to the engaging portion.

According to the third aspect, since the guide portion for guiding the moving direction of the movable holding portion is fixed to the engaging portion, the movable holding portion can be slid smoothly and reliably.

According to a fourth aspect of the present invention, in the narrow portion pickup tool according to the second aspect, a scale for reading a moving distance of the movable holding portion is provided on the fixed holding portion.

According to the fourth aspect, the scale for reading the moving distance of the movable holding portion is provided on the fixed holding portion, so that the grasping operation can be accurately confirmed and the reliability of the operation can be greatly improved. it can.

According to a fifth aspect of the present invention, in the narrow portion pickup tool according to the second aspect, the fixed pinch and the movable pinch are formed to be thinner than the distance between the fuel rods, and the fixed pinch is formed of a fuel rod having a stand. It has a length reaching the center.

According to the fifth aspect, the fixed pinch and the movable pinch are formed to be thinner than the distance between the fuel rods, and have such a length that the fixed pinch reaches the center of the established fuel rod. Foreign matter interposed between the fuel rods can be reliably removed.

According to a sixth aspect of the present invention, in the narrow portion pickup tool according to the second to fifth aspects, the lower surface of the movable holding portion is formed in a straight line.

According to the sixth aspect, the lower surface of the movable holding portion is formed in a straight line, so that the holding operation can be performed smoothly even in a portion where the hook is caught or a grating portion.
Foreign matter interposed between the fuel rods can be freely and remotely recovered underwater in a short time, and the working time can be greatly reduced.

According to a seventh aspect of the present invention, in the narrow part pick-up tool according to any one of the second to sixth aspects, an engaging projection is formed on one of contact surfaces of the fixed nipping part and the movable nipping part, and the other is formed on the other. An engagement recess is formed.

According to the seventh aspect of the present invention, since the engaging projection is formed on one of the contact surfaces of the fixed holding portion and the movable holding portion and the engaging recess is formed on the other, wire-like foreign matter can be removed. By being bent and sandwiched when collecting from a narrow part and being in a state of being not caught at the time of collection, foreign substances can be reliably collected.

According to an eighth aspect of the present invention, in the narrow part pickup tool according to any one of the second to sixth aspects, the contact surfaces of the fixed holding portion and the movable holding portion are each formed in a slope. I do.

According to the eighth aspect of the present invention, the contact surfaces of the fixed holding portion and the movable holding portion are each formed in a slanted shape, so that foreign objects can be gripped diagonally in parallel. Foreign matter can be easily collected from between, and work time can be greatly reduced.

[0026]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a front view showing a narrow portion pickup tool according to a first embodiment of the present invention, FIG. 2 is a plan view of FIG. 1, and FIG. 3 is a sectional view taken along line AA of FIG. Note that the fuel assemblies to be used in the present embodiment are the same as those shown in FIGS. 7 to 12, and will be described using the same reference numerals.

As shown in FIGS. 1-3, the tool body 10
Is operated to move to a predetermined position in the nuclear reactor by an operation pole (not shown) as an operation member, and has an engaging portion 11 with which the operation pole engages. The engaging portion 11 is formed in a bottomed cylindrical shape, and has an engaging groove 11a for engaging with a hook attached to the tip of the operation pole.

A mounting screw 12 is provided on the bottom surface of the engaging portion 11.
As a result, two guide plates 13 serving as guide portions are fixed, and a clip 14 is interposed between the guide plates 13. The clip 14 includes a fixed clip 15 fixed to the guide plate 13 and formed in a hook shape.
5 is movable (sliding) with respect to 5 and can be pressed into contact with the movable holding portion 16 formed in a long flat plate shape.
The thickness of the fixed sandwich 15 and the movable sandwich 16 is set to 3 mm and 2.5 mm, respectively, which are smaller than the distance between the fuel rods 2.

The fixed pinching portion 15 is set to have a length so as to reach the center of the fuel rods 2 when the clip 14 is inserted between the fuel rods 2.
Projecting from the guide plate 13 for at least half the length. On the other hand, the lower surface of the movable holding portion 16 is formed in a straight line.

The fixed holding portion 15 and the movable holding portion 16
When the movable clamp 16 slides and presses against the fixed clamp 15, the movable clamp 16 has contact surfaces 15 a and 16 a that contact each other, and the movable clamp 16 has an end opposite to the contact surface 16 a at an end thereof. One end of the connecting member 17 is connected, and the other end of the connecting member 17 is connected to a cylinder rod of an air cylinder 18 as driving means.

The upper surface of the air cylinder 18 has a joint 1
9 and 20 are attached, and these joints 19 and 20
Air supply hose 21 and air discharge hose 22 respectively
It is connected to the. A speed controller 23 is attached to the joint 20.
Thus, the operating speed of the air cylinder 18 can be controlled.

Therefore, when air is supplied from the air supply hose 21, the air cylinder 18 is driven, the cylinder rod is pushed out, and the movable holding portion 16 is slid along the guide plate 13 via the connecting member 17 to be fixed. Clip 15
The contact surface 16a of the movable sandwiching portion 16 is pressed against the contact surface 15a of the movable pinch. Here, the fixed pinch 15 is provided with a scale 15 b for reading the sliding distance of the movable pinch 16.

Next, the operation of the present embodiment will be described with reference to FIG.

After the fuel assembly is removed from the reactor pressure vessel during the periodic inspection of the boiling water reactor, the fuel assembly is transferred to a fuel pool (not shown) for inspection of the fuel assembly.
Here, the channel box is removed by the fuel attachment / detachment machine. In this state, the tool main body 10 is moved to the vicinity of the fuel bundle 6 by engaging the hook of the operation pole with the engagement groove 11 a of the engagement portion 11.

If it is found that foreign matter is present between the fuel rods 2 in the lower tie plate 4 while inspecting with a not-shown underwater camera and underwater illuminator, as shown in FIG. 4, the clip 14 is inserted between the fuel rods 2. The fuel rods 2 stand between the fuel rods 2 in a very narrow gap between the fuel rods 2, and a normal tool is a narrow portion where even insertion is difficult. In this state, the guide plate 13, the air cylinder 18, and the like are located outside the fuel bundle 6.

Next, air is supplied from the air supply hose 21 to drive the air cylinder 18, extrude the cylinder rod, and slide the movable holding portion 16 along the guide plate 13 via the connecting member 17 to fix the movable holding portion 16. Foreign matter is sandwiched between the contact surface 15a of the sandwiching portion 15 and the contact surface 16a of the movable sandwiching portion 16.

In this case, since the operating speed of the air cylinder 18 is controlled by the speed controller 23 and operates at a low speed, the movable holding portion 16 slides at a low speed, and the contact surface of the fixed holding portion 15 contacts. The foreign matter can be reliably sandwiched between the movable holding portion 15a and the contact surface 16a of the movable holding portion 16.

Further, the clip 14 is retracted from between the fuel rods 2 with the foreign matter pinched by the clip 14 and the tool body 10 is raised to the operation floor, and then the air is discharged from the air cylinder 18 to remove the cylinder rod. Degenerate,
The movable pinch portion 16 is slid in the opposite direction to the above to remove the pinched foreign matter.

As described above, according to the present embodiment, the tool body 10 includes the engaging portion 11 with which the operation pole engages, and the tool body 10 is inserted between the plurality of fuel rods 2 provided in the engaging portion 11 to remove foreign matter. The provision of the clipping device 14 and the air cylinder 18 for driving the clipping device 14 enables the foreign matter interposed between the fuel rods 2 to be freely and remotely collected underwater and in a short time and reliably. The time can be significantly reduced.

According to the present embodiment, since the guide plate 13 for guiding the sliding direction of the movable holding portion 16 is fixed to the engaging portion 11, the movable holding portion 16 can be slid smoothly and reliably. be able to.

Since the lower surface of the movable pinch portion 16 is formed in a straight line, the pinch operation can be performed smoothly even at a portion where the movable pinch portion is caught or at a grating portion, and foreign matter interposed between the fuel rods 2 can be freely moved underwater remotely. The collection can be performed in a short time, and the working time can be significantly reduced.

Further, the movable holding portion 16 is attached to the fixed holding portion 15.
By providing the scale 15b for reading the moving distance of the robot, the grasping operation can be accurately confirmed, and the reliability of the operation can be greatly improved.

The fixed holding portion 15 and the movable holding portion 16
Since the fixing pin 15 is formed thinner than the distance between the fuel rods 2 and has a length reaching the center of the fuel rods 2, the foreign substances interposed between the fuel rods 2 can be reliably removed. .

Although the present embodiment has described the case where foreign matter is present between the fuel rods 2 in the lower tie plate 4, the present invention is also applicable to the case where foreign matter is present between the fuel rods 2 in the upper tie plate or the spacer. This embodiment can be applied.

In this embodiment, the air cylinder 18 is used as the driving means, but an electric motor or the like may be used.

FIG. 5A is a front view showing a clipping tool according to a second embodiment of the narrow portion pickup tool according to the present invention, and FIG. 5B is a sectional view taken along line BB of FIG. 5A. .

As shown in FIGS. 5A and 5B, the clip 24 of the second embodiment comprises a fixed clip 25 and a movable clip 2.
6 and 45 ° slopes 25a and 26a respectively
Are formed. Also, on the bottom surface of the movable pinch portion 26,
A trapezoidal stepped recess 26b is formed.

Therefore, the contact surfaces between the fixed holding portion 25 and the movable holding portion 26 are provided with 45-degree slopes 25a, 26a respectively.
Due to the formation of a, the foreign matter is grasped diagonally in parallel, the foreign matter can be easily collected from between the fuel rods 2 that stand after the grasping operation, and the operation time can be greatly reduced.

The stepped concave portion 2 is formed on the bottom of the movable holding portion 26.
By forming 6b, even a foreign substance interposed in the concave portion can be used.
The contact surface between the fixed pinch portion 25 and the movable pinch portion 26 enters the recess, and can be easily grasped and reliably collected.

FIG. 6A is a front view showing a clipping tool in a narrow portion pickup tool according to a third embodiment of the present invention, and FIG. 6B is a cross-sectional view taken along line CC of FIG.

As shown in FIGS. 6A and 6B, the clip 27 of the third embodiment comprises a fixed clip 28 and a movable clip 2.
9 are provided on the contact surface with the engaging convex portion 28a and the engaging concave portion 2 respectively.
9a are formed. That is, the engagement protrusion 28a is 1
A triangular protrusion having an angle of 20 degrees,
9a is a V-shaped groove having an angle of 120 degrees.

Also, in this embodiment, similarly to the second embodiment, a trapezoidal stepped concave portion 29b is formed on the bottom surface of the movable sandwiching portion 29.

Therefore, by forming the engaging projections 28a and the engaging recesses 29a on the contact surfaces of the fixed holding portion 28 and the movable holding portion 29, the wire-like foreign matter is bent when it is collected from the narrow portion. As a result, the foreign matter can be surely collected because it is not caught and caught during collection.

In the present embodiment, the engaging projection 28a is formed on the fixed holding portion 28 and the engaging recess 29a is formed on the movable holding portion 29. However, the reverse configuration may be adopted. In addition, the shape does not need to be a combination of a protrusion having an angle of 120 degrees and a V-shaped groove, and may be a combination of an arc-shaped protrusion and a U-shaped groove.

[0056]

As described above, according to the present invention,
The tool body includes an engaging portion with which the operating member is engaged, a clipping device provided in the engaging portion and inserted between a plurality of fuel rods to clamp a foreign object, and a driving unit for driving the clipping device. As a result, foreign matter interposed between the fuel rods for some reason can be reliably collected in a remote location underwater in a short time.
As a result, sound combustion of fuel can be maintained, and safe operation and operation rate of the nuclear reactor can be improved.

[Brief description of the drawings]

FIG. 1 is a first view of a narrow portion pickup tool according to the present invention.
FIG. 1 is a front view showing an embodiment.

FIG. 2 is a plan view of FIG. 1;

FIG. 3 is a sectional view taken along line AA of FIG. 1;

FIG. 4 is a plan view showing a state in which the narrow portion pickup tool of FIG. 1 is inserted between fuel rods.

FIG. 5A is a front view showing a clipping tool according to a second embodiment of the narrow portion pickup tool according to the present invention, and FIG.
3A is a cross-sectional view taken along the line BB of FIG.

FIG. 6A is a front view showing a clipping tool according to a third embodiment of the narrow portion pickup tool according to the present invention, and FIG.
FIG. 4 is a cross-sectional view taken along line CC of FIG.

FIG. 7 is a perspective view showing a general fuel assembly.

FIG. 8 is a plan view showing the lower tie plate of FIG. 7;

FIG. 9 is a plan view showing the spacer of FIG. 7;

FIG. 10 is a configuration diagram showing an upper part of a fuel assembly.

FIG. 11 is a sectional view taken along line DD of FIG. 10;

FIG. 12 is a perspective view showing the upper part of the fuel assembly.

[Explanation of symbols]

 2 Fuel rod 4 Lower tie plate 6 Fuel bundle 10 Tool body 11 Engagement part 11a Engagement groove 12 Mounting screw 13 Guide plate (guide part) 14 Clipping tool 15 Fixed clipping part 15a Contact surface 15b Scale 16 Movable clipping part 16a Contact surface 17 Connecting member 18 Air cylinder (drive means) 19 Joint 20 Joint 21 Air supply hose 22 Air discharge hose 23 Speed controller 24 Clamp 25 Fixing clamp 25a Slope 26 Movable clamp 26a Slope 26b Stepped recess 27 Clamp Fixture 28 Fixed clip portion 28a Engagement convex portion 29 Movable clip portion 29a Engagement concave portion 29b Stepped concave portion

Continuation of front page (72) Inventor Tsuyoshi Maehara 2-4, Suehirocho, Tsurumi-ku, Yokohama-shi, Kanagawa Prefecture F-term in Toshiba Keihin Works (reference) 2G075 AA03 BA17 CA38 CA46 FC01 FC19

Claims (8)

[Claims] 1. A fuel assembly is removed from a reactor pressure vessel during a periodic inspection of a reactor, and foreign matter interposed between a plurality of fuel rods is removed underwater and remotely while a channel box is removed from the fuel assembly. A narrow-section pickup tool to be recovered, wherein a tool body is moved and operated by an operation member to a predetermined position in the nuclear reactor, and the tool body includes an engagement portion with which the operation member engages, A narrow part pick-up tool comprising: a holding member provided to be inserted between a plurality of fuel rods to hold a foreign object; and driving means for driving the holding member. 2. The narrow-pickup tool according to claim 1, wherein the clip has a fixed clip and a movable clip which moves by operation of a driving means and presses against the fixed clip. Narrow pick-up tool. 3. The narrow part pickup tool according to claim 1, wherein a guide part for guiding a moving direction of the movable holding part is fixed to the engagement part. 4. The narrow part pickup tool according to claim 2, wherein a scale for reading a moving distance of the movable pinch part is provided in the fixed pinch part. 5. The narrow-pickup tool according to claim 2, wherein the fixed pinch and the movable pinch are formed to be thinner than the distance between the fuel rods, and the fixed pinch reaches the center of the fuel rods. A narrow part pickup tool characterized by having a length. 6. The narrow portion pickup tool according to claim 2, wherein the lower surface of the movable holding portion is formed in a straight line. 7. The narrow-pickup tool according to any one of claims 2 to 6, wherein an abutment surface between the fixed nipping part and the movable nipping part has an engagement projection formed on one side and an engagement part on the other side. A narrow portion pickup tool characterized by having a concave portion. 8. The narrow portion pickup tool according to claim 2, wherein a contact surface between the fixed holding portion and the movable holding portion is formed in a slanted shape. Pickup tool.