JPH07229996A - Tool for coupling of control rod - Google Patents

Abstract

PURPOSE:To safely and surely rotate a bayonet type coupling part and detach a control rod from a spud of CRD (control rod drive mechanism). CONSTITUTION:A box 28 is connected to the lower end of a long size grid guide 26, and a rotation drive mechanism 27 is provided in the box 28. An L-shaped guide 47 is connected to the lower face of a frame base 31 of the lower end of the box 28. The L-shaped guide 47 is abutted a the blade face of a control rod 8. A hook 31 is mounted on the piston shaft of a cylinder 36 provided in the box 28. The hook 37 in engaged with a rack control rod 8 on a handle 23 of the control rod 8. When an air motor of the rotation drive mechanism 27 is driven and a pinion 34 and an internal gear 35 are rotated, the frame base 31 is rotated, a bayonet type coupling 10 is revolved and the control rod 8 can be detached from a spud 15 of CRD 9.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control rod coupling tool for detaching a bayonet type control rod coupling portion from a control rod drive mechanism (hereinafter referred to as CRD).

[0002]

2. Description of the Related Art In a boiling water reactor, fuel rods are moved during periodic inspections, and control rods are moved and replaced. Generally, in the control rod replacement work, after pulling out the fuel assembly and the fuel support fitting, the control rod is coupled with the coupling rod of the CRD, that is, the coupling is uncoupled to move the control rod.

FIG. 4 is an elevation view showing a part of a core of a boiling water reactor in a sectional view. FIG. 4 and FIGS.
The layout relationship between the fuel assembly and the control rods in the reactor and the coupling relationship between the control rods and the CRD will be described below.

In FIG. 4, reference numeral 1 is a reactor pressure vessel, and only a bottom portion thereof is partially shown. A support 2 is erected from the bottom of the reactor pressure vessel 1, and a shroud 3 is attached to the support 2.

An upper grid plate 4 is provided on the upper end of the shroud 3, and a core support plate 5 is provided on the upper end of the support 2 and in the horizontal direction from the inside of the shroud 3. A fuel support fitting 6 is provided on the core support plate 5, and a fuel assembly 7 is placed on the fuel support fitting 6. The fuel assembly 7 is a set of four bodies, and the outer upper part of the set of four bodies is the upper lattice plate 4
Horizontally supported within.

There is a cross-shaped gap in the center of the fuel assembly 7 of one set of four bodies, and a control rod 8 having a cross-shaped blade is inserted into this cross-shaped gap. The control rod 8 is connected to the CRD 9 penetrating the bottom surface of the reactor pressure vessel 1 by a bayonet type coupling portion 10 and is detachable. The CRD 9 is inserted in the control rod guide tube 11, and the upper portion of the control rod guide tube 11 is supported by the core support plate 5.

FIG. 5 is an enlarged view of the bayonet type coupling portion 10 of the control rod 8 and the CRD 9 in FIG.
FIG. 6 shows the insertion relationship between the fuel support fitting 6 and the control rod 8 in FIG. 4, and FIG. 7 shows the coupling and releasing states of the bayonet type coupling portion 10 as seen from the direction of arrows AA in FIG. Shows.

In FIG. 5, the control rod 8 has a speed limiter 12 at its lower part, and the speed limiter 12 is provided with a guide roller 13, which is a control rod guide tube 11.
It is in a state of sliding on the inner surface of the.

The bayonet type coupling portion 10 comprises a lock plug 14, a coupling spud 15, an uncoupled rod 16 and a socket 17. A socket 17 is connected to the lower surface of the speed limiter 12. CR
A coupling spud 15 is provided at D9.

As shown in FIG. 6, the fuel support fitting 6 has holes 18 at the upper four corners and a cross hole 19 at the center, and supports the lower ends of the fuel assemblies 7 one at a time at each of the holes 18 at the four corners. The control rod 8 moves up and down in the central cross hole 19.

As shown in Fig. 7 (a), the coupling spud 15 of the bayonet type coupling portion 10 is divided at its tip and is divided into a mountain portion 20 and a valley portion 21 every other. The corresponding socket 17 is also divided into the same number as the spud 15.

That is, the control rod 8 can be coupled (coupling) by rotating or twisting the control rod 8 by 45 degrees, that is, by twisting it in a state where the crest portion on the control rod 8 side and the trough portion on the CRD 9 side are matched. In this case, it can be carried out by reverse rotation as shown in FIG. 7B or by further rotating by 45 degrees. In FIG. 4, reference numeral 22 is a fuel assembly handle, and 23 is a control rod handle.

As described above, in the bayonet type coupling section 10 for connecting the control rod 8 and the CRD 9,
It was necessary to remove the fuel support fitting 6 in advance because the structure is such that it cannot be joined unless it is rotated more than 45 degrees. When the control rod 8 is rotated from the upper part of the furnace, C
The control rod 8 can be released from the connection by slowly and gradually rotating the control rod 8 without eccentricity with respect to the central axis of the RD 9.

[0014]

When the control rod 8 and the CRD 9 are coupled using the bayonet type coupling portion 10, the control rod 8 is rotated 45 degrees and then C
RD9 coupling spud 15 to control rod 8 socket
Engage with 17.

Therefore, since it is necessary to rotate the control rod 8, a rotating mechanism for the control rod 8 is required. Further, the upper lattice plate 4 holds the reaction force during rotation. further,
In order to prevent accidental fall prevention of the control rod 8, a hook for holding the handle 23 of the control rod at all times is required.

Since the control rod 8 in the nuclear reactor is a device having a length from the upper lattice plate 4 to the core support plate 5, it is necessary to prevent twisting and bending caused by rotation. If the speed is high when rotating the bayonet coupling of the control rod 8, there is an undesirable problem that the guide roller 13 of the control rod 8 causes frictional resistance on the inner surface of the control rod guide tube 11 due to centrifugal force or eccentricity. .

The present invention has been made to solve the above-mentioned problems. When a bayonet system is adopted for the coupling means of the control rod and the CRD, the control rod is
The object is to provide a control rod coupling tool that is most suitable for 45-degree rotation and that can be safely and securely attached and detached.

[0018]

SUMMARY OF THE INVENTION The present invention is a long grid guide suspended by a hoist of a refueling machine.
A box connected to the terminal of this grid guide,
A rotation drive mechanism provided in the box, a frame base provided at the lower end of the box through a bearing and seated on the handle upper surface of the control rod in the nuclear reactor, and the control rod blade surface attached to the frame base. An L-shaped guide for rotating the control rod in contact with the hook, a hook protruding from the frame base for hooking the handle of the control rod, and a cylinder and a piston shaft provided in the box for moving the hook up and down. It is characterized by having.

[0019]

The grid guide, the box and the L-shaped guide are connected together, and the grid guide is hoisted by the hoist of the fuel exchanger on the nuclear reactor and hung in the upper lattice plate. Insert the letter guide. When the frame base is seated on the upper surface of the control rod handle, the hook is projected from the inside of the box and hooked on the control rod handle to suspend it.

In this state, the handle of the control rod is not rotated, but the L-shaped guide inserted into the cross-shaped blade of the control rod is rotated by the rotation drive mechanism via the base frame, that is, 45.
According to the degree, the control rod is guided by the L-shaped guide and is out of phase by 45 degrees.

Accordingly, the bayonet type coupling portion can be rotated, so that the control rod is CR
Detachment work such as detaching from D or mounting can be performed safely and reliably.

The L-shaped guide is inserted along the cross-shaped blade surface of the control rod and guides until the base frame is seated on the upper surface of the handle of the control rod. In addition, the load of the control rod is moved to the center of the control rod guide tube while being suspended by the hoist, and the control rod is rotated to remove or attach the coupling portion.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a control rod coupling tool according to the present invention will be described with reference to FIGS. Note that FIG.
The same parts as those in FIG. 4 are designated by the same reference numerals, and the description of the overlapping parts will be omitted. Further, FIG. 1 (a) shows a state in which the control rod coupling tool of the present embodiment is suspended in the upper lattice plate 4, and FIG. 1 (b) is an enlarged view of the rotary drive mechanism in FIG. 1 (a) and its vicinity. Is shown.

In FIG. 1A, the tool for coupling the control rod of this embodiment is a hoist 25 of a refueling machine 24.
It has a long grid guide 26 suspended by. The lower end of the grid guide 26 is connected to a flange 29 on the upper surface of a box 28 that houses the rotary drive mechanism 27. A base frame 31 is provided at the lower end of the box 28 via a cross roller bearing 30.

The rotary drive mechanism 27 in the box 28 includes a support 32 standing from the base frame 31, an air motor 33 attached to the support 32, a pinion 34 attached to the rotation shaft of the air motor 33, and the pinion 34. It consists of an internal gear 35 that meshes with. The air motor 33 is driven by the gas pressure from a pneumatic hose 40 described later.

A cylinder 36 is provided in the box 28, and the cylinder 36 has a piston shaft (not shown).
The hook 37 is connected via. The hook 37 hangs the control rod 8 by hooking the handle 23 of the control rod.

An elongated tube 38 is appropriately supported in the grid guide 26 by a support member 39, and a hose 40 is inserted in the tube 38. This hose 40 has a grid guide 26
It is wound with the wire rope 44 by the hoist 25 passing through the top plate 41 that closes the upper end of the. The wire rope 44 is connected to the fastening metal fitting 43 of the stud 42 which is erected from the top plate 41. In the figure, reference numeral 45 is a rail, and 46 is a water surface in the reactor.

An L-shaped guide is provided on the lower surface of the base frame 31.
47 is connected. For the sake of convenience, the L-shaped guide 47 is also referred to as a first guide in order to distinguish it from second and third guides described later. The L-shaped guide 47 is formed in an angle shape by bending a slender flat plate at a right angle from the center as shown in FIGS. 2 (a) and 3 (a), and is formed on the cross-shaped blade surface of the control rod 8. It is abutted.

The L-shaped guides 47 are opposed to each other and are attached to the base frame 31 as a set. However, as shown in FIG. 2B, four guides 47 are used to control each of the control rods 8. It can also be brought into contact with the blade surface.

The L-shaped guide 47 is shown in FIGS. 3 (b) and 3 (c).
It can be formed into the shape shown in. The second guide 48 shown in FIG. 3 (b) shows an example in which the small rollers 49 are attached to the side surface with an appropriate interval, and the third guide 50 shown in FIG. 3 (c) is downward. A tapered surface 51 is formed that is tapered toward.

Next, the operation of the control rod coupling tool having the above structure will be described. For example, when the fuel assembly 7 is first moved during the periodic inspection and then the control rod 8 is moved, the fuel exchanger 24 is moved onto the rail 45 and the hoist 25 is wound above the target upper grid plate 4. To position.

Using the hoist 25, the fuel support fitting 6 is first removed. Next, it goes to the uncoupling of the control rod 8. In this case, when the fuel assembly 7 moves, the CR
D9 and the control rod 8 are pulled out to the lowest end. Most of the control rods 8 are housed in control rod guide tubes 11.

Therefore, when pulling up the fuel support fitting 6 next time, the step of passing through the control rod 8 is the minimum. Next, the fuel support fitting 6 is pulled out onto the upper grid plate 4 by the action of the hoist 25 using the graffle of the fuel support fitting 6.

The wire rope 44 to be wound up and unwound from the hoisting hoist 25 of the fuel exchanger 24 and the pneumatic hose 40 of the hose reel are bound to connect the wire rope 44 directly to the terminal fitting 43 on the grid guide 26. The pneumatic hose 40 extends through a tube 38 in the grid guide 26 to the end of the grid guide 26.

Next, the grid guide 26 and the L-shaped guide 47 are suspended by being tightly connected to the fastening member 43 at the end of the wire rope 44 of the hoisting hoist 25. Wait for insertion of the L-shaped guide 47 with the L-shaped guide 47 at the head and close to the control rod 8
At D9, the control rod 8 is pushed out until the control rod 8 is inserted, that is, the L-shaped guide 47 is completely inserted.

The top plate 41 of the grid guide 26 is the upper grid plate 4.
If you sit down, the descent will stop. The control rod 8 is an L-shaped guide
The insertion operation is continued until the entire length of 47 is completely inserted in the cruciform blade of the control rod. When the entire length of the L-shaped guide 47 is sufficiently in contact with the blade of the control rod 8, the upper surface of the handle 23 of the control rod and the frame base 31 are in contact with each other.

When the insertion of the control rod 8 is completed and the grid guide 26 and the control rod 8 come into contact with each other, the hook 37 on the frame base 31 is rotated by the cylinder 36 to be hooked and suspended on the handle 23 of the control rod. .

Next, the air motor 33 is driven to rotate and revolve the pinion 34 on the internal gear 35 to rotate the frame base 31 to the cross roller bearing 30.
When the frame base 31 is rotated, the L-shaped guide 47 fixed to the frame base 31 is rotated, and the control rod 8 is also rotated at a specified angle of 45 degrees.

By this rotation, the bayonet coupling portion of the control rod 8 causes a phase difference of 45 degrees with respect to the coupling spud 15 of the CRD 9. Make sure that CRD9 is retracted and uncoupled, and wire rope 44 is wound up and wound up by hoist 25.

By winding the wire rope 44, the top plate 41 is first hung up in a continuous manner with the grid guide 26, the box 28, and the control rod 8, but even if the control rod 8 is wound up on the upper lattice plate 4, the furnace is still in the furnace. A few meters below the water surface of the top plate
There is a water depth of up to 41. The control rod 8 is moved and fed into a fuel pool or the like which is normally connected to the core. In this case, the hook 37 hooked on the handle 23 of the control rod suspends the control rod 8.

Generally, an L-shaped guide is provided when the control rod 8 is used alone.
The control rod 8 reinforced by 47 has rigidity. When uncoupling by this action, the twisting or eccentricity of the guide roller 13 of the speed limiter 12 that directly contacts in the control rod guide tube 11 usually shows a large resistance to the rotation of the control rod 8, but it is L-shaped. Since the joint rigidity by the guide 47 increases the rigidity of the control rod 8, the detaching operation can be performed safely and reliably.

As shown in FIG. 2B, the L-shaped guides 47 shown in FIG. 2A are used as a pair of four as shown in FIG. When used in close contact, the bayonet type coupling portion can be more safely and reliably rotated.

When the length of the L-shaped guide 47 reaches the vicinity of the guide roller 13 of the speed limiter 12, the guide roller 13
Can be eliminated as much as possible, and at the same time, it greatly contributes to maintaining the rigidity of the control rod.

The small roller 49 provided on the second guide 48 shown in FIG. 3B is smoothly inserted without damaging the control rod 8 when the second guide 48 is inserted into the control rod 8. be able to. In addition, the third guide shown in FIG.
By forming the tapered surface 51 on the 50, the resistance when the third guide 50 is inserted into the control rod 8 is eliminated, which contributes to the improvement of the coupling work.

Since the L-shaped guide may be a vertical rectangular bar or a round bar, the L-shaped guide is not necessarily limited to the L-shaped angle. It is an L-shaped guide.

[0046]

According to the present invention, the bayonet type coupling portion can be safely and reliably rotated to detach the control rod from the CRD spat.

[Brief description of drawings]

FIG. 1 (a) is an elevation view showing an embodiment of a control rod coupling tool according to the present invention with a part cut away and a part sectional view;
(B) is a longitudinal cross-sectional view showing the rotation drive unit in (a) in an enlarged manner.

2 (a) is a top view showing a state where two L-shaped guides of the coupling tool in FIG. 1 are in contact with the blade surface of the control rod, and FIG. 2 (b) is four in FIG. The top view which shows the state which used the L-shaped guide of FIG.

3 (a) is an elevational view showing the L-shaped guide (first guide) in FIG. 1, FIG. 3 (b) is an elevational view and partial sectional view showing the same second guide, and FIG. Similarly, it is an elevation view showing the third guide, and the upper surface is also shown above in each drawing.

FIG. 4 is an elevation view showing a part of a core of a boiling water reactor in a partial cross section.

5 is an enlarged vertical sectional view showing a bayonet coupling mechanism between the CRD and the control rod in FIG.

FIG. 6 is a plan view showing an arrangement relationship between a fuel support fitting and a control rod in FIG. 4, viewed from above an upper lattice plate.

7 (a) is a cross-sectional view of the coupling state of the coupling spud of the CRD and the bayonet coupling of the control rod in FIG. 5, viewed from the direction of arrow AA, and FIG. 7 (b) is (a).
The cross-sectional view showing the released state.

[Explanation of symbols]

1 ... Reactor pressure vessel, 2 ... Support, 3 ... Shroud,
4 ... Upper lattice plate, 5 ... Core support plate, 6 ... Fuel support fitting,
7 ... Fuel assembly, 8 ... Control rod, 9 ... CRD, 10 ... Bayonet type coupling part, 11 ... Control rod guide tube, 12 ...
Speed limiter, 13 ... Guide roller, 14 ... Lock plug, 15 ... Coupling spud, 16 ... Uncoupled rod, 17 ... Socket, 18 ... Holes in upper four corners, 19 ... Cross hole in the center, 20 ... Mountain part, 21 ... Valley part, 22 ... Fuel assembly handle, 23 ... Control rod handle, 24 ... Fuel exchanger, 25 ... Hoisting hoist, 26 ... Grid guide, 27 ... Rotation drive mechanism,
28 ... box, 29 ... flange, 30 ... cross roller bearing, 31 ... base frame, 32 ... support, 33 ... air motor, 34 ... pinion, 35 ... internal gear, 36 ... cylinder, 37 ... hook, 38 ... tube, 39 … Support member, 40… Pneumatic hose, 41… Top plate, 42… Stud, 43… Fastener, 44
… Wire rope, 45… Rail, 46… Water surface, 47… L-shaped guide, 48… Second guide, 49… Small roller, 50… Third guide, 51… Tapered surface.

Claims (4)

[Claims] 1. A long grid guide suspended by a hoist of a refueling machine, a box connected to a terminal portion of the grid guide, a rotary drive mechanism provided in the box, and a lower end of the box. A frame base which is provided via a bearing and is seated on the upper surface of the handle of the control rod in the reactor; an L-shaped guide attached to the frame base to rotate the control rod in contact with the blade surface of the control rod; A tool for coupling a control rod, comprising: a hook protruding from a frame base for hooking the handle of the control rod; and a cylinder and a piston shaft provided in the box for vertically moving the hook. 2. The tool for coupling a control rod according to claim 1, wherein the L-shaped guide is provided with a roller that guides along the surface of the control rod blade and is rotatable in the circumferential direction. . 3. The tool for coupling a control rod according to claim 1, wherein the L-shaped guide is formed so as to taper toward a tip portion. 4. An air motor is attached to a support erected from the frame base at the lower end of the box in the rotary drive mechanism, and an internal gear meshing with the pinion is rotated by a pinion attached to a rotation shaft of the air motor, The control rod coupling tool according to claim 1, wherein the frame base to which the internal gear is attached is rotated by the rotation of the internal gear.