JP2987710B2 - Upper mirror opening and closing device - Google Patents

Description

The present invention relates to a tensioner system for attaching and detaching a dedicated hanging tool, a nut and a washer used for transferring an upper mirror of a boiling water reactor pressure vessel, for example. In particular, the present invention relates to an upper-mirror opening / closing device for a reactor pressure vessel suitable for shortening the time required for attaching and detaching an upper-mirror.

[Conventional technology]

Generally, as shown in FIG. 8, a reactor pressure vessel of a boiling water reactor is constructed by tightening an upper mirror flange 1a of an upper mirror 1 and a fuselage flange 2a of a fuselage 2 with stud bolts 3. Has a closed structure.

FIG. 9 shows details of the tightened state by the stud bolts 3. That is, as shown in FIG. 9, a large number (about 90 places) of body flange screw holes 2b are engraved in the body flange 2a of the body 2 with a circumferential interval therebetween. Correspondingly, the upper mirror flange 1a of the upper mirror 1 is provided with the same number of upper mirror flange through holes 1b extending in the vertical direction.

The stud bolt 3 is inserted into the upper mirror flange through hole 1b with one end (upper end) protruding above the upper mirror flange 1a of the upper mirror 1, and the stud bolt lower screw 3a at the other end (lower end) is connected to the body 2 Fuselage flange 2a fuselage flange screw hole 2b
Is screwed into. Then, a nut 4 is attached via a washer 5 to a stud bolt upper screw 3b at an upper end protruding portion of the stud bolt 3, and the upper mirror 1 and the body 2 are connected to a closed structure by a tightening force of the nut 4. You. The nut 4 and the washer 5 attached to the stud bolt 3 are arranged on the upper mirror flange 1a of the upper mirror 1 in the circumferential direction.
They are placed close enough to almost touch.

By the way, the reactor pressure vessel having a sealed structure including the stud bolts 3, the nuts 4, and the washers 5 is periodically inspected, for example, once a year for refueling or the like, and the upper mirror 1 is opened and closed. . In this case, the nut 4 and the washer 5 are removed from the stud bolt 3 to remove the upper mirror 1.
The tensioner system 11 shown in the figure is used. A head strong back 21 shown in FIG. 11 is used to transport the upper mirror 1 in the operation of removing the upper mirror 1 when the upper mirror 1 is opened.

Hereinafter, the tensioner system 11 for removing the nut 4 and the washer 5 when the upper mirror 1 is opened will be described.

When the upper mirror 1 is opened, the nut 4 tightening the stud bolt 3 is loosened by the stud tensioner 5 using the tensioner system 11 shown in FIG. 10, and all the nuts 4 and washers 5 are removed from the stud bolt 3. Then, the upper head 1 is moved from the body 2 to open the reactor pressure vessel and refueling is performed.
The upper mirror 1 is removed from the body 2 by suspending the upper mirror 1 from the head strong back 21 shown in FIG. After the upper mirror 1 is removed, replacement such as fuel exchange is performed. The upper mirror 1 is suspended by the head strong back 21 and attached to the body 2, and the washer 5 and the nut 4 are attached to the stud bolt 3 by the tensioner system 11. Attachment, nut 4 is tightened, and the reactor pressure vessel is closed by upper mirror 1.

Of the above operations, the nut 4 is loosened or tightened from the rail 13 fixed on the upper part of the stand 12 on the hanging bracket 6 of the upper mirror 1 via the electric chain block 14, as shown in FIG. This is performed using the tensioner system 11 in which a stud tensioner 15 is suspended.

On the other hand, when the upper mirror 1 is moved when the upper mirror 1 is opened, the eleventh
A head strong back 21 as shown in the figure is used. The head strong back 21 is suspended from a suspension box 25 provided at the center of the stiffener 22 by the overhead crane 9 and engages with the suspension fitting 6 of the upper mirror 1 via a fork end 23 and a turn buckle 24. The turnbuckle 24 is provided to hold the upper mirror 1 substantially horizontally when the upper mirror 1 is lifted and to adjust the load applied to the four turnbuckles 24 as evenly as possible.

In addition, since the stiffener 22 is bent when the upper mirror 1 is lifted, the stiffener 22 and the fork end 23 have a structure in which a pin is used so that bending stress is not generated at the root of the fork end 23. For this reason, when storing the headstrong back 21, the headstrong back 21 itself cannot stand alone, so the fork end 2
3. The portion of the turnbuckle 24 is bent and placed on the floor as shown in FIG. 12 for storage.

The tensioner system 11 and the upper mirror 1 were also stored on the floor.

[Problems to be solved by the invention]

In the prior art described above, taking the opening procedure of the upper mirror 1 as an example, when the tensioner system 11 is detached from the upper mirror 1 after the nut 4 is loosened by the tensioner system 11, the tensioner system 11 is placed on the upper mirror 1 In order to lift and move the upper mirror 1, it is necessary to replace the head strong back 21 on the upper mirror hanging bracket 6 of the upper mirror 1, and this replacement work is less efficient as a work under radiation management. Worse, the exposure of workers is also increased.

In the prior art, a storage space for storing two types of equipment, the tensioner system 11 and the headstrong back 21, is required in a limited space of the operation floor of the reactor building, and consideration is given to the effective use of the operation floor. I didn't.

An object of the present invention is to provide an upper-mirror opening / closing device capable of reducing the work corresponding to the replacement of a tensioner system and a head strong back under radiation management and effectively utilizing a storage space for these devices.

[Means for solving the problem]

The object is to allow a leg as a support member for horizontally supporting the device to be removably divided into an upper leg and a lower leg, and a suspending mechanism for suspending the upper mirror is arranged in the upper leg and the lower leg. By using a structure, the device is supported by legs as support members when standing up, the legs are split when the upper mirror is lifted, and the weight of the upper mirror can be supported by the lifting mechanism. This is achieved by integrating

[Action]

At the time of the tensioner system or during storage, the upper leg and the lower leg, which have been divided into upper and lower parts, are integrally connected, so that the device can be stored stably and independently. On the other hand, when lifting the upper mirror, the upper leg and the lower leg are divided into upper and lower parts, so that the weight of the upper mirror can be transmitted to the stiffener via a lifting mechanism arranged inside the upper leg and the lower leg. This makes it possible to integrate the tensioner system with the headstrong back, further reduces the work in the exposed environment, and eliminates the need to replace and work with the equipment, thus increasing the efficiency of work and storing the equipment. Occupied space (storage space) can be reduced.

〔Example〕

The configuration of an embodiment of the present invention will be described with reference to FIGS.

1 is a longitudinal sectional view showing the entire upper mirror opening / closing device, FIG. 2 is a plan view thereof, FIG. 3 is a detailed view of a portion B in FIG. 1, and FIG. 4 is a sectional view taken along line CC in FIG. FIG. 5 is a sectional view taken along line DD of FIG.

In FIG. 1, when the nut 4 and the washer 5 are attached to or removed from the stud bolt 3, the gantry 12 and the stiffener 22 must be free standing on the upper mirror as shown in FIG.

Therefore, the upper leg 37 and the lower leg 38 are connected by the bolt 39, and the upper leg 37 and the lower leg 38 have a self-standing structure.

When the upper mirror 1 is suspended (lifted or suspended), the upper leg 37 and the lower leg 38 are removed, and the upper leg 37 and the lower leg 38 are separated as shown in FIG. The upper mirror 1 is suspended by the suspension mechanism of the buckle 34.

1 and 3, one end of the lower leg 38 is fixed to a lug 34 which is fixed to the hanging bracket 6 of the upper mirror 1 by a pin 35, and the other end is a bolt 39 connected to the upper leg 37. Are connected by On the other hand, as shown in FIG. 4, one end of the upper leg 37 is fixed to a box 31 attached to the stiffener 22, and the other end of the upper leg 37 is connected to the lower leg 38 by bolts 39 to form the base 12, stiffener 22. Is upper leg 37, stock leg
By 38, it is comprised so that it may stably stand on the hanging bracket 6 independently.

In the upper leg 37 and the lower leg 38, a hanging rod 33 is
A turnbuckle 24 is provided, a lower end of the hanging bar 33 is connected to a lug 34 via the turnbuckle 24, and an upper portion is connected to a pin 32 rotatably supported in a box 31 attached to the stiffener 22. At right angles to 32, penetrate so that it can slide in the axial direction of the hanging rod 33, and a stopper at the upper end
36 are provided. (See FIGS. 3 to 5.) Therefore, the pin 35, the lug 34, the turnbuckle 24, the hanging bar 33, the stopper 36, the pin 32, and the box 31 constitute a hanging mechanism of the upper mirror 1. That is, as shown in FIG.
If the upper mirror 1 is lifted while it is connected to the lower leg 38 and the bolts 39 with the bolts 39, the upper mirror 1 is heavy, so that the stiffener 22 bends and the root of the upper leg 37 and the box 31 becomes excessively large. High bending stress occurs.

In order to eliminate this bending stress, as shown in FIG. 7, a bolt 39 connecting the upper leg 37 and the lower leg 38 is removed, the upper leg 37 and the lower leg 38 are separated, and a stopper 36 is attached to the upper surface of the pin 32. The stiffener 22 is slightly raised until the stiffener 22 hits the pin 32,
The stiffener 22 and the upper mirror 1 can be connected with the pin 35 via the stopper 36, the suspension rod 33, the turnbuckle 24, the suspension rod 33, and the lug 34, and no bending stress is generated even when the upper mirror 1 is suspended. .

In addition, a turnbuckle 24 is provided between the hanging rods 33.
By placing the upper mirror 1 on the pin 32 and the stopper 3
6, can be held substantially horizontally by a suspension mechanism including the suspension rod 33, the turnbuckle 24, and the suspension rod 33, and can be adjusted by the turnbuckle 24 so that the loads applied to the four suspension rods 33 are as uniform as possible.

The gantry 12 is integrally attached to a stiffener 22 so that an electric chain block 14 with a stud tensioner 15 suspended along a rail 13 provided on the gantry 12 can be moved. At the center of the stiffener 22, there is provided a suspension box 25 for engaging with the hook 9a of the overhead crane 9, as shown in FIGS.

The procedure for opening the upper mirror in the upper mirror opening and closing device configured as described above will be described with reference to FIGS.

First, as the work of loosening the nut 4 by the tensioner system 11 corresponding to FIG. 10 of the prior art, the hook 9a of the overhead crane 9 is attached to the hanging box 25 as shown in FIG. 6, and the entire upper mirror opening / closing device is lifted. The reactor is lowered onto the upper mirror 1 of the reactor pressure vessel, and the hanging metal 6 and the lug 34 of the upper mirror 1 are fixed with pins 35 as shown in FIGS. The upper mirror 1 is made to stand on the upper mirror 1 by the legs integrated with the lower leg 38 and the bolt 39. At this time, upper leg 37 and lower leg
Since 38 is connected by bolts 39 as shown in FIGS. 3 and 4, it can stand on the upper mirror 1 by itself.

In this state, the electric chain block 14 shown in FIG. 1 is operated, the stud tensioner 15 is sequentially lowered along the stud bolt 3, and the nut 4 is sequentially loosened by the stud tensioner 15. When all the nuts 4 have been loosened, the nuts 4 and washers 5 are all removed from the stud bolts 3.

Thereafter, in the prior art, the tensioner system 11 shown in FIG. 10 is lifted by the overhead crane 9 and detached from the upper mirror 1, and replaced with a head strong back 21. Eleventh
The head strongback 21 shown in the figure is suspended by the overhead crane 9 and set on the upper mirror 1, and the upper mirror 1 is lifted to
Was open.

In the upper mirror opening / closing device of the present invention, by removing the bolt 39 connecting the upper leg 37 and the lower leg 38, it is unnecessary to replace the conventional tensioner system 11 with the head strong back 21. As shown in FIG.
The hook 9a of the overhead crane 9 is attached to the suspension box 25, and the upper mirror opening and closing device and the upper mirror 1 are lifted together.

When the upper mirror 1 is lifted, the upper leg 37 shown in FIG.
By removing the bolt 39 joining the lower leg 38 and
As shown in FIG. 7, the upper leg 37 is also raised together with the box 31 attached to the stiffener 22, and the upper leg 37 is
Separate from At the same time, the pin 32 also slides upward in the axial direction of the suspension rod 33 and rises, and the upper surface of the pin 32 contacts the stopper 36.

That is, the weight of the upper mirror 1 is determined by
4, hanging rod 33, turnbuckle 24, hanging rod 33, stopper 36,
The upper mirror 1 is transmitted to the stiffener 22 via the pins 32 and the box 31, and the upper mirror 1 is lifted by these lifting mechanisms. At this time, since the upper and lower portions of the suspension bar 33 are connected by the pins 32 and 35, even if the stiffener 22 is bent, no bending moment is generated at the base of the suspension bar 33. Also, turn the turnbuckle 24 through the gap separating the upper leg 37 and the lower leg 38 to adjust the horizontal level of the upper mirror 1 or all hanging rods.
Adjustments can be made to evenly load 33.

Finally, in the process of moving the upper mirror 1 to the storage place and lowering it on the temporary storage table, the upper mirror 1 is installed on the temporary storage table in the reverse procedure to the above-described lifting. Then, when the overhead crane 9 is lowered, the stiffener 22 is lowered and the pin 32 is
The upper leg 37 descends onto the lower leg 38 by sliding downward from the hanging bar 33 in the axial direction, leaving the hanging rod 33, and is connected with the bolt 39. In this state, the load applied to the hanging bar 33 is eliminated, and the load is transferred to the upper leg 37 and the lower leg 38.

By connecting the upper leg 37 and the lower leg 38 with bolts 39 as shown in FIG. 3, the upper mirror opening / closing device can stand on the upper mirror 1 by the upper leg 37 and the stock leg 38. The apparatus can be stored on the upper mirror 1 in a state of being independent.

That is, the headstrong back 21 of the prior art cannot stand on the upper mirror 1 independently and has to be kept on the floor after the upper mirror 1 is moved. Can be stored independently on the upper mirror 1, and three locations are required to be stored in separate spaces of the conventional tensioner system 11, headstrong back 21 and upper mirror 1. Since the head 11 and the headstrong back 21 are integrated, the storage space is reduced by one.

〔The invention's effect〕

According to the upper mirror opening / closing device of the present invention, the legs supporting the upper mirror opening / closing device are detachably provided on the upper leg and the lower leg, and the suspension mechanism is provided inside the upper leg and the lower leg. And a suspension mechanism, so that a stand that suspends and operates the stud tensioner and a head strong back that lifts the upper mirror can be integrated, so that replacement work and labor for replacement can be reduced, In addition to the effect of improving work efficiency, there is an effect of reducing replacement work under radiation management and reducing exposure to workers.

Further, by integrating the tensioner base and the head strong back and storing them on the temporarily placed upper mirror, the storage space of the above two devices can be effectively used.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of the upper mirror opening / closing device according to the present invention, FIG. 2 is a plan view of FIG. 1, and FIG. 3 is an enlarged sectional view showing part B of FIG. 4 is a cross-sectional view taken along the line CC of FIG. 3, FIG. 5 is a cross-sectional view taken along the line DD of FIG. 3, and FIG. 6 lifts the upper mirror using the upper mirror opening / closing device of the present invention. FIG. 7 is an enlarged sectional view showing a portion E in FIG. 6, FIG. 7 is an enlarged sectional view showing a reactor pressure vessel, and FIG. 9 is an enlarged portion A in FIG. FIG. 10 is a side view of a tensioner system used for tightening and loosening a conventional nut, and FIG. 11 is a side view showing a state where an upper mirror is lifted using a conventional head strong back. Figure, No.
FIG. 12 is a side view showing a state in which a conventional headstrong back is stored on the floor. 1 top mirror, 2 body, 3 stud bolts 4 nuts 5 washers 6 hanging brackets 9 overhead crane 9a hooks 12 hooks 13 rails 14 … Electric chain block, 15… Stud tensioner, 22… Stiffener, 24… Turnbuckle, 25… Hanging box, 31… Box, 32… Pin, 33… Hanging rod, 34… Lug, 35 ... Pin, 36 ... Stopper, 37 ... Upper leg, 38 ... Lower leg, 39 ... Bolt.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁶ , DB name) G21C 13/00-13/02 G21C 19/02

Claims (1)

(57) [Claims] An upper mirror opening / closing device for attaching and detaching an upper mirror of a pressure vessel of a boiling water reactor, wherein legs of the upper mirror opening / closing device are detachably divided into an upper leg and a lower leg. An upper mirror opening / closing device, wherein a suspension mechanism for suspending the upper mirror is disposed in a leg and a lower leg.