JPS5855898A - Closing device of reactor main steam nozzle - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a closing device capable of sealing a main steam nozzle of a reactor pressure vessel and illuminating the inside of the reactor pressure vessel during periodic inspections.

Periodic inspections of boiling water reactors include, for example, fuel changes. This fuel exchange involves replacing the fuel assembly loaded in the core within the reactor pressure vessel with a new one, and a fuel exchange machine is used to replace this fuel assembly. This fuel exchange machine is placed on the work floor above the reactor pressure vessel, and when exchanging fuel, one worker is required to operate the fuel exchange machine from the work floor and exchange the fuel assemblies. There is. In addition, when performing such fuel exchange, the work floor is far above, and the reactor pressure vessel and the reactor well above the pressure vessel are filled with water for cover-up. Therefore, the location of the reactor core is dark and difficult to see. For this reason, during fuel exchange, lighting is required to illuminate the inside of the reactor pressure vessel, that is, the reactor core. Conventionally, underwater lighting was installed by hanging from the fuel exchange machine, and this underwater lighting was used to illuminate the vicinity of the fuel assembly to be replaced. Local view: It is designed to illuminate. However, when working with underwater lighting equipment such as this,
There was a problem with this underwater lighting device shaking and not providing reliable lighting. Furthermore, since the suspension cable also sways as the underwater lighting equipment sways, the water surface of the reactor well also sways, resulting in poor visibility within the reactor core.

By the way, during the above-mentioned periodic inspection, maintenance and inspection of the main steam system is performed in parallel with fuel exchange, and a blocking device is used for this maintenance and inspection of the main steam system. This closure device is installed inside the reactor pressure vessel, and its closure plug is inserted into the main steam nozzle to seal the main steam nozzle. It has become. As described above, during periodic inspections, there is installation work such as installing the above-mentioned underwater lighting equipment and the above-mentioned closure device inside the reactor pressure vessel, but conventionally, these installation works were performed at one side. For this reason, since each installation work requires work time, the periodic inspection period becomes long, and there is a problem that the amount of radiation exposure of the workers increases.

This invention was made based on the above circumstances, and its purpose is to stably illuminate the reactor pressure vessel during fuel exchange by providing the above-mentioned underwater lighting device. Another object of the present invention is to provide a closure device for a nuclear reactor main steam nozzle that can shorten periodic inspection time and reduce radiation exposure to workers.

That is, the present invention provides a cooling plug that is removably inserted into a main steam nozzle and seals the main steam nozzle in an air-water tight manner, and a cooling plug that is inserted into the main steam nozzle after the plug is inserted.

A ring-shaped support ring is provided along the inner circumferential surface of the reactor pressure vessel at the main steam nozzle position to prevent the blockage plug from popping out into the reactor pressure vessel. The feature is that a plurality of underwater lighting devices are provided along the direction.

An embodiment of the present invention will be described below based on Figure 1 to Figure 1≦2.

Figure 1 shows a boiling water reactor, and 1 in Figure 1 is a reactor pressure vessel. This reactor pressure vessel l has a reactor core 2 built therein.

At the top, there are multiple (usually 4) main steam nozzles 3...
・ is provided. These main steam nozzles 3 are connected to main steam pipes 4, respectively.

The boiling water nuclear reactor is configured to introduce steam generated in the reactor core 2 to a power generation turbine through these main steam pipes 4, and drive the power generation turbine to generate power. In addition, a pair of main steam isolation valves 6.6 are provided in the main steam pipes 4, respectively, with the reactor containment vessel wall 5 in between. A relief valve 7 is provided. 8 is the working floor of the reactor building. In addition, Figure 1 shows the reactor pressure vessel during periodic inspection! Remove the inner lid (not shown) and open the reactor well. %I and the reactor well Q are filled with water for shielding.

During such periodic inspections, the main steam nozzle 3 is installed inside the reactor pressure vessel 1 in order to carry out maintenance and inspection of the main steam system.
As the closure device 10 of... is inserted and installed:
The structure of the closure device 10 will be explained below with reference to FIGS. 2 to 6. In the figure, 11 is a base. This base 11 consists of two beams 13.13 connected by connecting members 12 at the center and both ends, and both ends of these beams 13.13 are connected to the main steam nozzles 3, respectively, when inserted. It is configured to face the In addition, the connecting member 12... has hanging ears 14 for hanging.
... is provided.

By connecting wire ropes to these hanging ears 14, the entire closure device 10 can be suspended by an overhead crane of the reactor building. On the beams 13, 13 (:), cooling plugs I5... are provided on both end sides, respectively.

The blockage plug 15... consists of a cylindrical body 16 with a diameter smaller than the inner diameter of the main steam nozzle 3, and the tip thereof has a σ-ra 17...
・ is provided. Further, a hollow hydraulic seal 18 and a pneumatic seal 19 are provided on the outer periphery of the intermediate portion of the cylindrical body 16, respectively.
is provided, and an O-ring 20 is provided at the rear end.
is provided. Further, 21... is an assembly of hoses that supply water and air to the hydraulic seal 1B and the pneumatic seal 19. And the blockage plug 15...
A trolley 22... is provided behind each of the
These carts 22... are capable of reciprocating in the longitudinal direction on the beams 13, 13 by means of hydraulic cylinders 23.... Moreover, 24... is the wheel of the trolley|bogie 22....

As shown in FIG. 3, the carts 22... and the blocking plugs I5... are connected by hook-shaped connections IL25a, 25b that engage with each other, and each of the carts 22... Main steam nozzle 3 due to reciprocating movement
The closing plug 15 is configured to be pushed out and pulled back in the direction of insertion and removal from the plug. In addition, the connection between the first carriage 22 and the blockage plug 15 is the connection between the first carriage 22 and the blocking plug 15.
It can be released by moving the 2... side upward. In addition, the cold-closing plug 15... is placed on the beam 13° I3 with the insertion/extraction guide 26...
(It is supported by two. This insertion/extraction guide 26...
・It is fixedly installed on the 1st beam JJ and 13th.

The front end side of the cold-closing plug 15...rear end C: is detachably inserted.

A support 11 ring 27 is provided on the side of the base 11 (=&j support 11 ring 27).
It is composed of a frame 28 that can be divided, and the frame 28 has a ring shape along the inner peripheral surface of the reactor pressure vessel 1. and.

Frame 28 has beams 13.13 as shown in FIG.
The connecting rods 29...41 and the hydraulic cylinders 30...≦2 provided on the beams 73, 13 can be inserted into and removed from the frame 28. It's happening.

Therefore, the support ring 2761 is detachably supported on the base 11. In addition, 3
Reference numerals 1m and 31b denote support l; an engaging portion that positions the pufferfish 27 and the base 11. Further, an outer positioning guide 32,32 of the frame 28 is provided.

These positioning guides 32.32 are the reactor pressure vessel! Inner guide rods 33, 331: are fitted and guided to position the entire closure device 10 in the local direction, that is, to position the insertion and removal direction of the closure plugs 15 with respect to the main steam nozzles 3. Also, frame 2
An upper support 34... is provided on the outer periphery of 8. These upper supports 34 project laterally from the upper part of the frame 28 and can engage with dryer support brackets 35 on the inner surface of the reactor pressure vessel 1. Further, when the upper supports 34... and the dryer supports 35... are engaged, the closing plugs I5... are positioned in the height direction with respect to the main steam nozzles 3.... Note that these dryer support brackets 35 are used to support a steam dryer (not shown) during operation of the nuclear reactor. The frame 28 also has an upper support 34 as shown in FIG.
... are provided with lower supports 36, respectively. These lower supports 36 are normally accommodated within the frame 28.

The hydraulic cylinder 37...:;Therefore, it can protrude toward the dryer support bracket 35... side. In addition, the lower supports 36... are made to protrude, and these lower supports 36... and the dryer support brackets 35... are made to protrude.
. . C; is the main steam nozzle position (the two paired support rings 27 are positioned in the height direction), and the frame 28
Inside is the pressing rod 38...
is accommodated. These pressing rods 38 are located below the closing plugs 15..., and the hydraulic cylinders 39...
This makes it possible to protrude and retract from the frame 28 toward the inner surface of the reactor pressure volume IS1.

The support ring 27 is provided with an underwater lighting device 40.
... is provided. These underwater lighting devices 40... are arranged in the circumferential direction [:] at the bottom of the frame 28..., and are adapted to irradiate light toward the interior center C: of the spore reactor pressure volume iSl, respectively. will be explained with reference to FIGS. 5 and 6. Arms 4J and 41 project downward from the lower part of the frame 28.

The lighting device main body 42 is attached between these arms 41, 41. The lighting main body 42 is configured by accommodating, for example, a plurality of halogen light bulbs 44 in a plastic lamp case 43 having translucent and waterproof properties, 45 is a socket for the halogen light bulb 44, and 46 is a halogen light bulb. 44 reflective hats. Also, 47 is lamp case 4
This is a protective wire mesh provided on the outer surface of 3. One end of a cabtire cable 48 for power supply is connected to the lighting device main body 42 via a waterproof rubber sheath 49, and the other end of this cabtire cable 48 is connected to the working floor surface of the reactor building. It is led up to the top and connected to a power outlet. Na-b, so is a switch box. In this embodiment, the lighting main body 42 is supported via a pivot 51 between the arms 41 and 41, and is rotatable about the pivot 51. A disc 52 for setting the illumination direction is fixed to one end of the pivot 51, and a plurality of engagement holes 53 are formed on the surface of the disc 52 at equal pitches on the circumference. ing. Further, a setting lever 54 is attached to the T-m 41 of the disc 52, and this setting lever 54 has a projection (not shown) that can fit into the engagement holes 53...C. It is provided. Therefore, by fitting the projection into an arbitrary engagement hole 53, the rotation angle, that is, the irradiation angle of the lighting device main body 42 can be adjusted and fixed.

Next, the operation of the closed IK device 10 having the above configuration will be explained.

First, during periodic inspection, the base closing plugs 15 and the support ring 27 are attached to the base 11 on the work floor 8 to assemble the entire device, and the base closing device 10 is lifted by an overhead crane. Then, by this overhead crane, the closing device 1
0 to the upper part of the reactor pressure vessel 1, and this closing device 10 is gradually inserted into the reactor pressure vessel 1.

Now, the positioning guide 32, 32 is fitted and guided by the guide rod 33, 33, and the closure device 10 is inserted, and the closure device IO, that is, the closure plug 15.
... is positioned in the circumferential direction. Also,
When the closure device 10 is submerged in water, the underwater lighting device 40
... to illuminate the inside of the reactor pressure vessel 1.

It is also used as lighting for installing the base closing device 10. Then, the closing device 10 is further suspended, and the upper supports 34 of the support ring 28 are engaged with the dryer support brackets 35 as shown in FIG. 3
I support it with 5... At this time, the above-mentioned blocking plug 15.
... and the main steam nozzle 3 ... face each other, and the closed base plug 1
5... is positioned in the height direction. Thereafter, by operating the hydraulic sills 23..., the blockage plugs 15... are pushed out through the first cylinder 22..., and these blockage plugs 15... are connected to the respective main steam nozzles 3. ...Insert inside. Furthermore, at this time.

The occlusion plugs 15... slide on the beams 13.13, as shown in the diagram, and the hydraulic seals 1B... and the pneumatic seals 1
9... Inner shell: Water and air are respectively supplied to inflate these hydraulic seals 18... and pneumatic seals 19..., thereby sealing the main steam nozzle 3... in an air-watertight manner. Then, lift the base 11 side and lift the sabot 1-IJ song B to a position slightly above the main steam nozzle position.

At this time, the connector 25 between each blockage plug 15 and the trolley 22
The engagement of a and 25b is caused by the rise of the base 11, that is, the carriage 22.
: They come off together, and these connections are released. Then, after operating the hydraulic cylinders 37 to cause the lower supports j6 to protrude from the frame 28, the base II side is gradually suspended again. Then, the lower supports 36 are engaged with the dryer support brackets 35 as shown in FIG. 8C2, and the support ring/f27 is installed on the dryer support brackets 35. At this time, this support ring 27 is positioned at the main steam nozzle position. Also, the hydraulic cylinder 39... is operated to press the rod 3.
8 are made to protrude from the frame 28, and these pressing rods 38 suppress and hold the closing plugs 15, respectively, as shown in FIG. And after this,
Activate the hydraulic cylinder 30... and connect the connecting rod 29.
... is pulled out from the frame 28 to release the connection between the support ring 28 and the base 11, and then the base 11 is lifted and removed from the reactor pressure vessel 1. At this time, as shown in FIG. 10, the closing plugs 15 of the closing device 10 and the support ring 27 remain inside the reactor pressure vessel. After sealing the main steam nozzle 3 in this way.

Main steam isolation valves 6, etc. of the main steam system are removed and maintenance and inspection are carried out: 2. Steam pressure is applied inside the main steam pipes 4, and the main steam pipes 4 and the Steam isolation valve 6...
・It is used to perform leakage tests such as. In addition.

Even when steam pressure is applied inside the main steam pipe 4, the blockage plug 15 is held down by the support ring 27, so the blockage plug 1 due to the steam pressure C2 is held down by the support ring 27.
5... can be reliably stopped from jumping out.

Furthermore, during such periodic inspections, fuel replacement work is performed in parallel with maintenance and inspection of the main steam system. During this fuel exchange, the underwater lighting fixtures 40 installed on the support ring 27 are lit to illuminate the entire area inside the reactor well 57. , visibility of the vicinity of the reactor core 2 from the work floor 8 is good, and work efficiency can be improved.In addition, during such fuel exchange, there is no blockage in the reactor pressure vessel l as shown in FIG. Since only the support ring 27 of the device 10 remains, it does not interfere with the fuel exchange operation in any way.

In addition, the underwater lighting equipment 40... is supported by a support ring 27.
Since the underwater lighting fixtures 4o are installed in the reactor pressure vessel 1, the underwater lighting fixtures 4o do not shake during fuel exchange unlike conventional hanging types, and the inside of the reactor pressure vessel 1 can be reliably and stably illuminated. can. Furthermore, unlike in the case of the conventional hanging type, the water surface of the reactor well 9 does not shake due to the shaking of the underwater lighting fixtures 40, that is, the swinging of the hanging wire, so that the work floor is The visibility of the inside of the furnace from 8 can be further improved.

Furthermore, the reactor pressure vessel 1 of the underwater lighting device 40...
Since the internal installation can be done at the same time as the installation of the obstruction device lθ support ring 27, the work time required to install the underwater lighting A40 itself can be omitted compared to conventional hanging type ones. . As a result, the regular inspection period can be shortened, and the amount of radiation exposure of workers can be reduced.

Further, according to this embodiment, since the illumination angle of the underwater lighting fixtures 40 can be varied, it is possible to intensively illuminate the areas where it is needed, and the illumination effect is high.

Note that this invention is not limited to the above-mentioned actual example. For example, the mechanism for changing the illumination angle of the lighting fixture main body 42 may be as shown in FIGS. 11 and 12. That is, in this case, a worm wheel 6o is provided at one end of a pivot shaft 51 that supports the lighting device main body 42, and a worm gear 61 is meshed with the worm wheel 60. Further, an operating rod 62 connected to the support ring 27 is connected to the worm gear 6I, and the upper end of the operating rod 62 has a shape into which a hexagonal wrench box or the like can be fitted. Therefore, by fitting a long wrench onto the upper end of the operating rod 62 from above the work floor 8 and rotating the operating rod V62, the lighting main body 42 is rotated via the worm gear 61b and the worm wheel 60. If so,
The illumination angle of the lighting fixture main body 42 can be changed even during fuel replacement work.

As explained above, the present invention provides a closing plug that is removably inserted into a main steam nozzle and seals the main steam nozzle in an air-water tight manner, and a nuclear reactor that opens at the main steam nozzle position after the closing plug is inserted. A ring-shaped support ring is positioned along the inner peripheral surface of the reactor pressure vessel to prevent the blockage plug from popping out into the reactor pressure vessel, and a plurality of submersible rings are provided below the support ring along the local direction. It is characterized by the provision of lighting equipment. Therefore, since the underwater lighting equipment is attached to the support ring, there is no possibility that the underwater lighting equipment will shake during the fuel exchange operation, and the water surface will not shake due to the shaking of the underwater lighting equipment. The inside of the reactor pressure vessel can be illuminated reliably and stably, and the visibility inside the reactor pressure vessel can be improved. In addition, since the work required to install the underwater lighting equipment itself can be omitted, the periodic inspection period can be shortened, reducing the amount of radiation per worker is exposed to, and the operating rate of the reactor can be improved, among other benefits. .

[Brief explanation of the drawing]

1 to 10 show an embodiment of the present invention, in which FIG. 1 is a sectional view of a reactor pressure vessel, FIG. 2 is a partially sectional side view of a closure device, and FIG. 3 is a sectional view of a closure device. A plan view of the device, Fig. 4 is a sectional view taken along the line ■-fV in Fig. 3, and Fig.
v-■ line C in the figure: A cross-sectional view along
A cross-sectional view taken along the Vl line, Fig. 7 is a view immediately after the closing plug is inserted into the main steam nozzle, Fig. 8 is a cross-sectional view of the support ring showing when one part of the support is protruding, and Fig. 9 is a view showing the support ring when it is pressed. FIG. 1O, which shows the rod protruding, is a cross-sectional view of the reactor pressure vessel with the base removed when the plug is inserted. It is a side view of the underwater lighting device seen from the 11th direction. 1... Reactor pressure vessel, 3... Main steam nozzle. 15...Occlusion plug, 27...Support ring. 40...Underwater lighting equipment, 41...Arm.

Claims (2)

[Claims] (1) A closed plug that is removably inserted into the main steam nozzle from the inside of the reactor pressure vessel and seals the main steam nozzle air-tight, and atoms at the main steam nozzle position after the plug is inserted. A ring-shaped support ring is positioned along the inner peripheral surface of the reactor pressure vessel to prevent the blockage plug from popping out into the reactor pressure vessel, and a plurality of underwater lights are installed along the circumferential direction at the bottom of this support ring. A device for blocking a main steam nozzle of a nuclear reactor, characterized in that a device is provided with a device. (2) The nuclear reactor main steam nozzle closing device as set forth in claim (1), wherein the underwater lighting ^ is rotatably attached to the lower part of the support ring.