JP2002131467A - Wrench for shroud head bolt - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wrench by which the loosening operation and the tightening operation of a shroud head bolt can be performed in a short time and surely. SOLUTION: The wrench 40 for the shroud head bolt is suspended from the upper part of a reactor pressure vessel, and it performs the loosening operation and the tightening operation of the bolt remotely in the water. The wrench is provided with a socket 56 which can be fitted to a nut 13, a socket rotation and drive means 41 which turns and drives the socket 56, an operating socket 58 which is used to operate the rotating position of a lock member and a lock- member drive means 60 which turns the operating socket 58.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shroud head bolt suspended from above a refueling machine in order to handle a shroud housed in a reactor pressure vessel and a shroud head bolt tightening the shroud head underwater remotely. About a wrench.

[0002]

2. Description of the Related Art FIG. 7 is a longitudinal sectional view showing a schematic configuration of various in-reactor equipment housed in a reactor pressure vessel which is a reactor vessel of a boiling water reactor. As shown in FIG. 7, inside a reactor pressure vessel (not shown) of a boiling water reactor, a reactor core 1 composed of a large number of fuel assemblies (not shown) is housed. The lower and upper portions of the core 1 are supported by a core support plate 2 and an upper lattice plate 3, respectively.

[0003] The outer periphery of the core 1 is surrounded by a cylindrical shroud 4, and the top of the shroud 4 is covered by a shroud head 5 which is one of the in-furnace equipment.
The shroud head 5 forms a core upper plenum 5 a above the core 1. A number of standpipes 6 are provided on the upper surface of the shroud head 5, and a steam separator 7 is provided at the top of each standpipe 6.

The coolant heated in the core 1 flows into the upper core plenum 5a as a two-layer flow (mixed air-water flow), and the two-layer flow is uniformly mixed in the upper core plenum 5a. You. The two-layer flow uniformly mixed in the core upper plenum 5a is guided to the steam separator 7 via the stand pipe 6, and the steam separator 7 performs gas-liquid separation of the two-layer flow. The steam separated from the two-layer stream by the steam separator 7 is guided to a steam dryer (not shown) disposed above the steam separator 7 and dried by the steam dryer.

[0005] A boiling water reactor is a nuclear reactor that uses a heat generated by a nuclear fission reaction in the reactor core 1 to heat a coolant to generate steam. Pressure and temperature rise. Therefore, an upward pressure is applied to the shroud head 5 during the operation of the reactor. Therefore, in order to prevent displacement of the shroud head 5 due to pressure during operation of the reactor, the shroud head 5 is fastened and fixed to the upper part of the core shroud 4 by several tens of shroud head bolts 8.

Further, by fixing the shroud head 5 to the core shroud 4 as described above, it is possible to prevent the stand pipe 6, the steam separator 7 and the like from falling down when an earthquake occurs.

FIGS. 8 (a) and 8 (b) show the structure of the shroud head bolt 8, and as shown in FIGS. 8 (a) and 8 (b), the shroud head bolt 8 is a long cylindrical outer pipe. 9 is provided. An inner rod 10 longer than the outer pipe 9 is inserted into the outer pipe 9 so as to be vertically movable. This inner rod 10
Is formed by integrally joining the inner rod upper 10a and the inner rod lower 10b by welding.

The lower part of the inner rod lower 10b is
A T-shaped tee bar 11 as a locking member is provided at a lower end of the inner rod lower 10b so as to protrude downward from a lower end opening of the outer pipe 9. The upper surface of the tee bar 11 is engaged with the lower surface of the lower shroud head bolt lug 12.

On the other hand, a nut 13 such as a hexagon nut is screwed above the inner rod upper 10a.
A nut lock 14 is provided below the nut 13 so as to be vertically movable. The nut lock 14 is urged upward by the spring force of the spring 16, and the rotation of the nut 13 is restricted by fitting the nut lock 14 into a corner of the nut 13.

A lower end of the outer pipe 9 has a flange 18a.
Is provided, and this base 18 is fitted in a lug groove 19 a of an upper shroud head bolt lug 19 fixed to the shroud head 5. The flange 18a of the base 18 is engaged with the upper surface of the upper shroud head bolt lug 19.

As shown in FIG. 7, a number of stand pipes 6 and a steam separator 7 provided on the upper part of the shroud head 5 are supported by a lower guide ring 20 and an upper guide ring 21, respectively. As shown in FIG. 8A, engagement holes 20a and 21a are formed in the lower and upper guide rings 20 and 21, respectively, and the shroud head bolt 8 penetrates the engagement holes 20a and 21a. are doing. The shroud head bolt 8 has spacers 23 at positions corresponding to the engagement holes 20a and 21a.
And a head 22 are provided, respectively, and the spacer 23 and the head 22 are engaged with engaging holes 20a, 21a of the lower and upper guide rings 20, 21, respectively.

Next, the operation when the shroud head 5 is attached to the shroud 4 by the shroud head bolt 8 will be described.

When the shroud head 5 is mounted on the shroud 4, the nut 13 at the upper end of the shroud head bolt 8 is rotated to lower the inner rod 10, and the tee bar 11 of the inner rod 10 and the base 18 of the outer pipe 9 Is increased in advance. Then, the teaser 11 is inserted into the lug groove 12a from above the lower shroud head bolt lug 12 and passed therethrough.

Next, the inner rod 10 is rotated 90 degrees using a special wrench (not shown) and the nut 1 is rotated.
3 to rotate the tiba 1 integrally with the inner rod 10.
Move 1 up. Then, the upper surface of the tee bar 11 is pressed against the lower surface of the lower shroud head bolt lug 12, and the lower surface of the flange portion 18 a of the base 18 is pressed against the upper surface of the upper shroud head bolt 19. The shroud head bolt lugs 12 are tightened and the shroud head 5
Is fixed to the upper part of the shroud 4. In addition, Tiba 1
When rotating 1 by 90 degrees, the direction of the tee bar 11 can be confirmed by the direction of the rectangular projection 24 at the upper end of the inner rod 10. Then, the rotation of the nut 13 is restrained by fitting the nut lock 14 to the corner of the nut 13.

The inner rod 10 constituting the shroud head bolt 8 is formed of a nickel-based alloy, for example, Inconel 600, while the outer pipe 9
Is formed of stainless steel. Here, since the thermal expansion coefficient of the Inconel 600 is smaller than that of stainless steel, when the inner rod 10 and the outer pipe 9 become high temperature during the operation of the reactor, the outer pipe 9 made of stainless steel becomes the inner rod 10 made of Inconel. It expands more in the axial direction than it does. The upper end of the outer pipe 9 is fixed to the upper end of the inner rod 10 by a nut 13, while the lower end of the outer pipe 9 is
At 8a, it is fixed to the upper surface of the upper shroud head bolt 19. Therefore, when the outer pipe 9 expands more than the inner rod 10, the shroud 4 and the shroud head 5 are further firmly tightened.

Further, at the time of periodic inspection of the reactor, the shroud head 5 is removed from the shroud 4 after the reactor is stopped. Shroud head 5 to shroud 4
To remove from the nut, first, the nut lock 14 is pushed down, and the nut 13 is rotated with a special wrench to lower the inner rod 10 and the teaser 11,
The inner rod 10 is rotated 90 degrees. By rotating the inner rod 10 by 90 degrees, the
Is a direction that can pass through the lug groove 12a.

The work of loosening the shroud head bolt 8 is performed by a worker on the refueling machine using a long special wrench.

After all the shroud head bolts 8 have been loosened according to the above procedure, a shroud head suspension 26 is suspended just above the shroud head 5 on a hook of a crane 25 provided at the upper part of the reactor building as shown in FIG. Lower. Here, if the inside of the reactor well 28 (see FIG. 9) is full, the wire rope 27 of the crane 25 is immersed in the water in the reactor well 28 when the shroud head suspension 26 is lowered. Would. Reactor well 28
Since the water inside contains radioactivity, wire rope 27
Must be prevented from contacting this contaminated water.

Therefore, when the shroud head suspension 26 is lowered, the water surface of the reactor well 28 is also lowered in accordance with the descent of the shroud head suspension 26 so that the wire rope 27 is not submerged.

In this manner, the shroud head suspension 2
After the 6 is lowered to just above the shroud head 5, the hook of the shroud head hanging device 26 is connected to the hanging ear, and the wire rope 27 is wound up by the crane 25.
Then, the shroud head bolt 8 is pulled up together with the shroud head 5, the tee bar 11 of the shroud head bolt 8 passes through the lug groove 11a, and the shroud head 5 is removed from the core shroud 4. The shroud head 5 removed from the core shroud 4 is transferred to the equipment storage pool 29 (see FIG. 9).

Here, when the shroud head 5 is lifted, the water level of the reactor well 28 is raised in accordance with the rise of the shroud head 5, and the shroud head 5 is always transferred in water.

FIG. 10 is a cross-sectional view showing a mounting state of the shroud head bolt guide pins. As shown in FIG. 10, two shroud head bolt guide pins 30 are attached in advance to guide the mounting of several tens of shroud head bolts 8 when fixing the shroud head 5 to the shroud 4. A long rod 31 penetrating through the engagement holes 20a, 21a of the guide ring 20 and the upper guide ring 21, a positioning portion 32 provided at the lower end of the rod 31, and a nut 33 screwed to the upper end of the rod 31. And

The positioning portion 32 has a large-diameter portion 32a formed at the lower end thereof so as to fit into the lug groove 12a of the lower shroud head bolt lug 12, and the large-diameter portion 3a.
Above 2a, a small diameter portion 32b that can be fitted to a bush 34 fitted in the lug groove 19a of the upper shroud head bolt lug 19 is provided continuously.

When the shroud head 5 is fixed to the shroud 4, dozens of shroud head bolts 8 are inserted into the lug grooves 19 of the upper shroud head bolt lugs 19.
a and the lug groove 19a of the upper shroud head bolt lug 19 and the lug groove 12a of the lower shroud head bolt lug 12 are relatively positioned in advance so as to easily penetrate the lug groove 12a of the lower shroud head bolt lug 12. There is a need.

For this purpose, a shroud head bolt guide pin 30 is used. That is, the nut 33 is previously tightened with a special wrench to move the rod 31 upward, the large diameter portion 32a of the positioning portion 32 is fitted into the lug groove 12a of the lower shroud head bolt lug 12, and the upper shroud head bolt lug 19 is engaged. Bush 3
The lug groove 19a of the upper shroud head bolt lug 19 and the lug groove 12a of the lower shroud head bolt lug 12 are relatively positioned by fitting the small-diameter portion 32b to 4.

During operation of the reactor, the nut 33 is loosened and the rod 31 is moved downward, so that the large diameter portion 32a of the positioning portion 32 is fitted to the lug groove 12a of the lower shroud head bolt lug 12. When the bush 34 of the upper shroud head bolt lug 19 is released,
2b is released so that an unreasonable load is not applied to the shroud head bolt guide pin 30.

[0027]

By the way, in the above-mentioned prior art, the work of loosening several tens of shroud head bolts 8 using a long special wrench from the fuel exchanger requires a great deal of labor.

The lower shroud head bolt lug 1
When pulling up the tee bar 11 through the lug groove 12a of the second, the tee bar 11
2, the inner rod 10 could not be pulled up smoothly.

Further, when the shroud head 5 is moved up or down in the reactor well 28 (see FIG. 9), the water level of the reactor well 28 must be raised and lowered in accordance with the elevation of the shroud head 5. Therefore, the shroud head 5 must be moved up and down slowly in accordance with the water level elevating speed.

For the various reasons described above, the work of removing or attaching the shroud head 5 from the core shroud 4 requires a long time, and the period of the periodic inspection is prolonged, which only lowers the operation rate of the nuclear power plant. However, there is a problem that the radiation exposure of workers is increased.

The present invention has been made in order to solve the above-mentioned problem, and shortens the work of loosening and tightening a shroud head bolt for fixing a shroud housed inside a reactor pressure vessel and a shroud head. An object of the present invention is to provide a shroud head bolt wrench that can be performed in time and reliably.

[0032]

According to the first aspect of the present invention, a nut is provided at an upper end of a shroud head bolt for fixing a shroud head to a shroud in a reactor pressure vessel. A shroud head provided at the lower end with a locking member that is locked to a bolt lug fixed to the shroud in a rotational direction, and loosening and tightening the nut suspended from above the reactor pressure vessel and remotely underwater. A bolt wrench, a socket that can be fitted to the nut, a socket rotation driving unit that rotationally drives the socket, an operation socket for operating a rotation position of the locking member, and an operation socket. And a locking member driving means for driving to rotate.

According to the first aspect of the present invention, the work of loosening and tightening the shroud head bolts performed at the time of the periodic inspection of the nuclear reactor can be reliably performed in a short time, and the radiation exposure of the workers can be greatly reduced. it can.

According to a second aspect of the present invention, in the shroud head bolt wrench according to the first aspect, the socket rotation drive means includes a drive motor and a torque control means for controlling a rotation torque of the drive motor. It is characterized by.

According to the second aspect of the present invention, since the torque control means for controlling the rotation torque of the drive motor is provided, the tightening torque of the shroud head bolt can be reliably controlled, and the operation of the reactor can be improved. Safe operation can be maintained.

According to a third aspect of the present invention, in the shroud head bolt wrench according to the first aspect, a fitting confirmation means for confirming whether or not the socket is fitted to the nut is provided on a seating base of the wrench body. It is characterized by having.

According to the third aspect of the present invention, since the fitting confirmation means for confirming whether or not the socket is fitted to the nut is provided, the work of loosening the shroud head bolt can be reliably performed. The safe operation of the reactor can be maintained.

According to a fourth aspect of the present invention, in the shroud head bolt wrench according to the first or third aspect, positioning means for positioning the wrench main body is provided, and the wrench main body is positioned by the positioning means and the locking member is provided. Is characterized in that the rotational position of can be controlled.

According to the fourth aspect of the invention, the positioning means for positioning the wrench main body is provided, and the rotational position of the locking member can be controlled by positioning the wrench main body, thereby loosening and tightening the shroud head bolt. In the invention according to claim 5, the work can be performed reliably and the safe operation of the nuclear reactor can be maintained. In the shroud head bolt wrench according to claim 1, the shroud has the socket attached to the shroud head. When fixing the shroud head bolt, the nut can be fitted to a nut of a shroud head bolt guide pin for guiding the mounting of the shroud head bolt.

According to the fifth aspect of the present invention, since the socket can be fitted to the nut of the shroud head bolt guide pin, a plurality of types of equipment can be handled, so that the cost can be reduced and the storage space can be effectively used. An effect such as utilization can be obtained.

[0041]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a shroud head bolt wrench according to the present invention will be described below. The components constituting the core equipment of the boiling water reactor shown in FIG. 7 to FIG.

FIG. 1 is a longitudinal sectional view showing an embodiment of a shroud head bolt wrench according to the present invention, FIG. 2 is a side view of FIG. 1, FIG. 3 is a plan view of FIG. 1, and FIG. FIG. 5 is an enlarged sectional view taken along line BB of FIG. 1, and FIG. 6 is an enlarged sectional view taken along line CC of FIG. 1.

In the shroud head bolt wrench 40 of this embodiment, a nut 13 is provided at the upper end of a shroud head bolt 8 for fixing the shroud head 5 to the shroud 4 in the reactor pressure vessel, and is fixed to the shroud 4 at the lower end. 1 as a locking member that is locked in the rotating direction with the lower shroud head bolt lug 12 set
1 is provided, and the work of loosening and tightening the nut 13 is suspended from above the reactor pressure vessel and performed underwater remotely.

As shown in FIGS. 1 and 2, the shroud head bolt wrench 40 includes a socket rotation drive unit 41 as a socket rotation drive unit, a drive transmission unit 42 for transmitting the driving force of the socket rotation drive unit 41, The wrench main body 43 receives the driving force from the drive transmitting section 42.

The socket rotation drive section 41 has a cylindrical storage case 44 as shown in FIG. 1, in which a drive motor 45 is stored in a liquid-tight manner.
The output shaft 46 of the drive motor 45 is connected to a harmonic drive 47. A connector 4 that can be connected to an operation pole (not shown) is provided on the top of the storage case 44.
8 is fixed. This connector 48 is usually used for positioning by suspending it with a wire rope 27 (shown in FIG. 9). However, if a flow of reactor water or the like occurs, an operating pole is connected to the connector 48. The positioning can be performed while guiding from above the refueling machine.

The drive transmission section 42 has a transmission section case 49 formed of a flat elliptical box as shown in FIG. 3, and the transmission section case 49 has a harmonic as shown in FIGS. A rotary shaft 50 connected integrally with the drive 47 is provided, and a gear 51 is fixed to the rotary shaft 50. A small gear 52 meshes with the gear 51, and the number of rotations of the small gear 52 is detected by a rotation number detector 5.
2a, and based on the detection signal of the rotation speed detector 52a, the drive motor 45
The rotational torque of the motor. That is, the torque control means 52b controls the rotation torque of the drive motor 45 by adjusting the drive voltage of the drive motor 45 based on the detection signal of the rotation speed detector 52a.

The gear 51 meshes with a large gear 53, and the large gear 53 is fixed to the upper end of a socket of a wrench body 43 described later. And transmission part case 4
As shown in FIGS. 1 and 3, a plurality of eye bolts 54 are screwed on the upper surface of the wire 9 at a distance from each other, and the wire rope 27 (shown in FIG. 9) or the like is hooked on these eye bolts 54. The shroud head bolt wrench 40 of the present embodiment is suspended from above the reactor pressure vessel so that handling operations can be performed remotely underwater.

The wrench body 43 has a cylindrical case 55 whose upper part is fixed to the lower part of the transmission part case 49 by welding.
In this cylindrical case 55, a socket 56 that can be fitted with the nut 13 of the shroud head bolt 8 is installed concentrically with the cylindrical case 55, and this socket 56 is fixed to the lower surface of the large gear 53.

The socket 56 has a shape and a size that can be fitted to the nut 33 of the shroud head bolt guide pin 30 shown in FIG. 10 for guiding the mounting of the shroud head bolt 8.

A guide cylinder 57 is installed concentrically in the socket 56, and an operation socket 58 that can be fitted to the projection 24 for operating the rotation position of the tee bar 11 is installed concentrically on the guide cylinder 57. Have been. A gear 59 is fixed to the upper end of the operation socket 58, and the gear 59 is attached to the output shaft of a rotary cylinder 60 as a locking member driving means disposed at the upper end of the guide cylinder 57.
1 is engaged.

The operating socket 58 is formed in a hollow cylindrical shape as shown in FIG. 1 and has a notch 5 formed by combining a plurality of sectors as shown in FIG.
8a are formed. Thereby, the operation socket 5
8 can be fitted to the rectangular projection 24 at any rotational position.

Further, the cylindrical case 55 of the wrench body 43
A seating base 62 seated on the upper guide ring 21 is fixed to the lower end of the base by welding, and a locking projection 63 protruding vertically downward and engaging with an end of the upper guide ring 21 is provided on the bottom surface of the seating base 62. Has been fixed.

Therefore, a positioning means for positioning the wrench body 43 is constituted by the seating base 62 and the locking projection 63. That is, the locking projection 63 prevents the wrench body 43 from moving in the horizontal direction, and the seat base 62 prevents the wrench body 43 from moving in the vertical direction. As a result, the wrench body 43 is positioned, so that the operation socket 58 can be rotated and the rotation position of the teaser 11 can be reliably controlled.

As shown in FIG. 6, the seat base 62 is provided with a plurality of limit switches 64 as fitting confirmation means for confirming whether or not the socket 56 is fitted to the nut 13 of the shroud head bolt 8. It has been installed. That is, the nut 1 of the shroud head bolt 8
The plurality of limit switches 64 operate only when the socket 56 is fitted to the socket 3 and the seating base 62 of the wrench body 43 is seated on the upper surface of the upper guide ring 21, so that the socket 56 is fitted to the nut 13. Can be confirmed.

Further, in this embodiment, whether or not the nut lock 14 is fitted to the nut 13 may be confirmed by an underwater TV camera (not shown).

Next, a procedure for loosening the shroud head bolt 8 arranged in the reactor pressure vessel using the shroud head bolt wrench 40 according to the present embodiment will be described.

First, after stopping the operation of the reactor, the upper lid of the reactor pressure vessel is removed. Next, the steam dryer is lifted upward using the crane 25 of the reactor building and transferred to the equipment storage pool 29. Then, when the steam dryer is transferred to the equipment storage pool 29, reactor water is injected into the reactor, and the reactor well 28 is filled with water.

When the reactor well 28 becomes full as described above, the shroud head bolt 8 is shrunk using the shroud head bolt wrench 40 shown in FIGS.
According to the following procedure. That is, first, the shroud head bolt wrench 40 is connected to the auxiliary hoist of the refueling machine, and the shroud head bolt wrench 40 is lowered to be engaged with the head of the shroud head bolt 8 so that the shroud head bolt The seat base 62 of the wrench 40 is seated. When the seat is seated in this manner, when the plurality of limit switches 64 incorporated in the seat base 62 are operated, the shroud head bolt wrench 40 is set in a correct state.

At the same time, the socket 56 incorporated in the wrench main body 43 is used for the nut 1 of the shroud head bolt 8.
3 and the lower end of the socket 56 is pressed against the upper end of the nut lock 14.

Then, the nut lock 14 pressed downward by the socket 56 is pressed downward against the urging force of the spring 16 shown in FIG. 8, and the fitted state between the nut 13 and the nut lock 14 is released. .

After the shroud head bolt wrench 40 has been fitted into the nut 13 of the shroud head bolt 8, the drive motor 45 shown in FIG.
A rotational driving force is output from the output shaft 46 via the harmonic drive 47, the rotating shaft 50, and the gear 51 to a large gear 53.
And the socket 56 is rotated.

At this time, by detecting the number of rotations of the small gear 52, the torque control means 52
b adjusts the voltage of the drive motor 45 and controls the rotational torque of the drive motor 45, thereby preventing damage to the nut 13 and the like.

When the shroud head bolt 8 is tightened, the rotation direction of the socket 56 by the drive motor 45 is reversed so that the nut 13 is reversed.
The pseudo head bolt 8 can be tightened.

The direction of the tee bar 11 provided at the lower end of the inner rod 10 can be changed by rotating the short projection 24 provided at the upper end of the inner rod 10. That is, the operation is performed by driving the rotor cylinder 60, transmitting the rotational driving force to the operation socket 58 fitted into the projection 24 via the gear 59, and rotating the operation socket 58.

Thereafter, the shroud head bolt wrench 4
0 and lift the next shroud head bolt 8
And repeat the above procedure.

The shroud head bolt wrench 40
If a plurality of are used, the work of loosening the shroud head bolt 8 can be performed at the same time.

After the above procedure is repeated to loosen all the shroud head bolts 8, the crane 25 of the reactor building
Is used to lift the shroud head 5, and the shroud head 5 is transferred to the equipment storage pool 29. Then, a predetermined operation such as a refueling operation is performed.

After the refueling operation is completed, the shroud head 5 and the steam dryer are moved from the equipment storage pool 29 to a predetermined position in the reactor pressure vessel by performing the above procedure in reverse order. Can be attached back.

As described above, by using the shroud head bolt wrench 40 according to the present embodiment, a large number of the shroud head bolts 8 of the shroud head 5 can be loosened and fastened underwater remotely and quickly. Alternatively, the mounting can be performed reliably in a short time.

Therefore, not only the radiation exposure of the workers can be significantly reduced, but also the period of regular inspection of the nuclear reactor can be shortened and the operation rate of the nuclear power plant can be improved.

Further, according to the present embodiment, the socket rotation drive section 41 includes the drive motor 45 and the drive motor 45.
With the provision of the torque control means for controlling the rotation torque, the tightening torque of the shroud head bolt 8 can be reliably managed, and the safe operation of the reactor operation can be maintained.

Further, according to the present embodiment, the socket 5
By providing a limit switch 64 on the seating base 62 of the wrench body 43 for checking whether the nut 6 is fitted to the nut 13 of the shroud head bolt 8, the work of loosening the shroud head bolt 8 can be performed reliably. And safe operation of the reactor can be maintained.

According to the present embodiment, the seating base 6 as positioning means for positioning the wrench body 43 is provided.
2 and the locking projection 63 are provided, and the wrench body 43 is positioned by the seating base 62 and the locking projection 63 so that the rotation position of the tee bar 11 of the shroud head bolt 8 can be controlled, thereby loosening the shroud head bolt 8. In addition, the fastening operation can be reliably performed, and the safe operation of the reactor can be maintained.

According to the present embodiment, the socket 56
When fixing the shroud head 5 to the shroud 4,
The shroud head bolt wrench 40 can be fitted to the nut 33 of the shroud head bolt guide pin 30 for guiding the mounting of the shroud head bolt 8.
Can handle a plurality of types of equipment, so that effects such as reduction in cost and effective use of storage space can be obtained.

Further, in the present embodiment, when a plurality of shroud head bolt wrenches 40 are provided, the workability of loosening and tightening the shroud head bolt 8 can be improved, and the periodic inspection of the nuclear reactor can be greatly shortened. be able to.

[0076]

As described above, according to the shroud head bolt wrench according to the present invention, the shroud head bolt for tightening the shroud head and the shroud can be loosened or tightened, so that the shroud head can be removed or attached. In a short time and reliably.

Therefore, not only the radiation exposure of the workers can be significantly reduced, but also the period of regular inspection of the nuclear reactor can be shortened and the operation rate of the nuclear power plant can be improved.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing one embodiment of a shroud head bolt wrench according to the present invention.

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

FIG. 3 is a plan view of FIG. 1;

FIG. 4 is an enlarged sectional view taken along line AA of FIG. 1;

FIG. 5 is an enlarged sectional view taken along line BB of FIG. 1;

FIG. 6 is an enlarged sectional view taken along line CC of FIG. 1;

FIG. 7 is a longitudinal sectional view showing a schematic configuration of a reactor device of a boiling water reactor.

8A is a side view showing the shroud head bolt in FIG. 8, and FIG. 8B is a side view showing the outer pipe in a partial cross section by cutting the outer pipe in FIG. 8A.

FIG. 9 is an explanatory view showing a state in which a furnace internal structure is moved to an equipment storage pool.

FIG. 10 is a sectional view showing an attached state of a shroud head bolt guide pin.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Core 2 Core support plate 3 Upper lattice plate 4 Shroud 5 Shroud head 6 Stand pipe 7 Steam separator 8 Shroud head bolt 9 Outer pipe 10 Inner rod 10a Inner rod upper 10b Inner rod lower 11 Teaver (locking member) 12 Lower part Shroud head bolt lug 12a Lug groove 13 Nut 14 Nut lock 16 Spring 18 Base 19 Upper shroud head bolt lug 20 Lower guide ring 21 Upper guide ring 22 Head 23 Spacer 25 Shroud head hanger 27 Wire rope 28 Reactor well 29 Equipment storage pool Reference Signs List 30 Shroud head bolt guide pin 31 Rod 32 Positioning part 33 Nut 34 Bush 40 Shroud head bolt wrench 41 Socket rotating drive Unit (socket rotation drive unit) 42 Drive transmission unit 43 Wrench main body 44 Storage case 45 Drive motor 46 Output shaft 47 Harmonic drive 48 Connector 49 Transmission unit case 50 Rotary shaft 51 Gear 52 Small gear 52a Rotation speed detector 52b Torque control unit 53 Large gear 54 Eyebolt 55 Cylindrical case 56 Socket 57 Guide cylinder 58 Operating socket 59 Gear 60 Rotary cylinder (Locking member driving means) 61 Gear 62 Seating base (Positioning means) 63 Locking projection (Positioning means) 64 Limit switch (Fit) Verification means)

Claims (5)

[Claims] 1. A nut provided at an upper end of a shroud head bolt for fixing a shroud head to a shroud in a reactor pressure vessel, and a lower end of the nut being locked to a bolt lug fixed to the shroud in a rotational direction. Provide a member, loosen and tighten the nut,
What is claimed is: 1. A shroud head bolt wrench that is suspended from above the reactor pressure vessel and is remotely operated underwater, comprising: a socket fittable to the nut; socket rotation driving means for driving the socket to rotate; A shroud head bolt wrench comprising: an operation socket for operating a rotation position; and a locking member driving means for rotating the operation socket. 2. A shroud head bolt wrench according to claim 1, wherein said socket rotation drive means includes a drive motor and torque control means for controlling a rotation torque of said drive motor. Bolt wrench. 3. The shroud head bolt wrench according to claim 1, wherein a fitting confirming means for confirming whether said socket is fitted to said nut is provided on a seating base of said wrench body. Shroud head bolt wrench. 4. The shroud head bolt wrench according to claim 1, further comprising positioning means for positioning said wrench main body, said positioning means positioning said wrench main body to control the rotational position of said locking member. Shroud head bolt wrench characterized by the following. 5. The shroud head bolt wrench according to claim 1, wherein the socket is fitted with a nut of a shroud head bolt guide pin for guiding the mounting of the shroud head bolt when fixing the shroud head to the shroud. Shroud head bolt wrench characterized by the possibility.