JPS6050491A - Blocking device for main steam nozzle of nuclear reactor - 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 [Technical Field of the Invention] The present invention relates to an R11 plugging device that can hermetically plug a main steam nozzle of a nuclear reactor pressure vessel and illuminate the inside of the reactor pressure vessel during periodic inspections.

[Technical background of the invention and its problems] Generally, during periodic inspections of boiling water reactors, maintenance and inspection of the main steam system are performed in parallel with fuel replacement, and a blocking device is used for this maintenance and inspection of the main steam system. used.

This blocking device is installed inside the reactor pressure vessel, and by inserting the blocking plug into the main steam nozzle, the main steam nozzle is hermetically sealed.This device is used to perform leakage tests of the main steam system, etc. There is. On the other hand, fuel exchange involves replacing the fuel assembly loaded in the core within the reactor pressure vessel with a new one, and a fuel exchanger is used to replace this fuel assembly. This fuel exchange machine is placed on a work floor above the reactor pressure vessel, and when exchanging fuel, workers operate the fuel exchange machine from the work floor to replace fuel assemblies.

By the way, when performing such a fuel exchange, the upper two working floors are located far above, and the inside of the reactor pressure vessel and the reactor well above this pressure vessel are filled with water for ``a'' cover. As a result, the location of the reactor core is dark and difficult to see.

For this reason, during fuel exchange, a lighting device is required to illuminate the core inside the reactor pressure vessel. Conventionally, an underwater lighting device was hung from the fuel exchange machine each time a fuel assembly was handled, and this underwater lighting device was used to illuminate the fuel assembly that needed to be replaced. It is designed to locally illuminate the area around the body.

Therefore, conventionally, during periodic inspections, the above-mentioned closing device was installed inside the reactor pressure vessel, and each time the fuel assembly was handled, the above-mentioned underwater lighting equipment was hung from the fuel exchange machine, thereby allowing fuel exchange and main steam system maintenance and inspection. was going on.

However, when the underwater lighting equipment is hung each time a fuel assembly is handled, there is a problem in that the underwater lighting equipment shakes during the work, making it impossible to provide reliable illumination. Since the suspension cable also sways, the water surface of the reactor well also sways, resulting in poor visibility inside the reactor core. Furthermore, since it takes time to lift and lower the underwater lighting equipment, periodic inspection periods become longer, and because the underwater lighting equipment cables are lifted and lowered to the floor, there is no dust in the work area. There was a risk that the dose would be high and the radiation exposure of workers would increase.

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

[Summary of the Invention] In order to achieve the above object, the present invention provides an RFL plug that is removably inserted into a main steam nozzle and seals the main steam nozzle in an air-water tight manner; a ring-shaped support ring that is positioned along the inner circumferential surface of the reactor pressure vessel at the main steam nozzle and prevents the plug from popping out into the reactor pressure vessel;
This support ring is characterized by a configuration including a plurality of underwater lighting devices attached along the circumferential direction of the support ring.

[Embodiment of the Invention] An embodiment of the invention will now be described with reference to FIGS. 1 to 10.

Figure 1 shows a boiling water nuclear reactor, where 1 is the reactor pressure vessel. This reactor pressure vessel 1 houses a reactor core 2, and the upper part of the reactor pressure vessel 1 houses a plurality of reactor cores (usually four
) main steam nozzles 3... are provided. These main steam nozzles 3 are connected to main steam pipes 4, respectively, and guide the steam generated in the reactor core 2 through these main steam pipes 4 to a power generation turbine to drive this power generation turbine. It is designed to generate electricity. In addition, a pair of main steam isolation valves 6.6 are provided in each of the main steam pipes 4 with the reactor containment vessel wall 5 in between.
A pressure relief valve 7 is provided that operates when there is an abnormal pressure within the reactor pressure vessel 1. Further, reference numeral 8 is a working floor of the reactor building. Note that Figure 1 shows the state in which the lid (not shown) inside the reactor pressure vessel 1 is removed during periodic inspection, and the inside of the reactor pressure vessel 1 and the reactor well 9 are filled with water for shielding. It shows.

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.
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. 11 in FIG. 2 is a base. As shown in FIG. 3, this base 11 has two beams 13 connected at the center and at both ends by connecting members 12.
13, and both ends of these frames 13, 13 are configured to face the main steam nozzles 3, respectively, when inserted. The connecting members 12 are provided with hanging ears 14 for hanging, and wire ropes are connected to these hanging ears 14 so that the entire closing M device 10 can be moved from the ceiling of the reactor building. It can be lifted with a crane. Also, on the beams 13 and 13, there are plugs 15 at both ends.
...is provided. These occlusion plugs 15...
consists of a cylindrical body 16 with a smaller diameter than the inner diameter of the main steam nozzle 3, and a roller 17 is generally cut out at the tip thereof, and a hollow hydraulic seal 18 and a pneumatic seal are respectively provided on the outer periphery of the intermediate part. One is provided. Further, an O-ring 20b is provided at the rear end of the cylindrical body 16. Note that the reference numerals 21 . . . are a collection of hoses that supply water and air to the hydraulic seal 18 and the pneumatic seal 19.

Carts 22... are provided behind the blocking plugs 15, respectively, and these carts 22... can be reciprocated in the longitudinal direction on the beams 13, 13 by hydraulic cylinders 23... It has become. The carriages 22 and the closing plugs 15 are hook-shaped connectors 25a that engage with each other as shown in Figure M3.

25b, and the trolleys 22...
The reciprocating movement of the plugs 15 is configured to push out and pull back the plugs 15 in the direction of insertion into and removal from the main steam nozzles 3. And trolley 22...
The connection between the block plug 15 and the block plug 15 can be released by moving the carriage 22 upward. Further, the blocking plugs 15... are supported by insertion/extraction guide kites 26... on the beams 13.13.

This insertion/extraction guide 26... is fixedly provided on the beam 13.13, and its tip side is attached to the occlusion plug 15.
It is removably inserted into the rear end of... In addition, the code|symbol 24... is a wheel of the trolley|bogie 22....

On the other hand, an I-ring 27 is provided on the side of the base 11. This support ring 27 is composed of a frame 28 that can be divided into four parts, and has a ring shape along the inner peripheral surface of the reactor pressure vessel 1. The frame 28 is connected to the beams 13, 1.3 via connecting rods 29, as shown in FIG. The hydraulic cylinders 30 can be inserted into and removed from the reframe 28.

Therefore, the support ring 27 is supported on the base 11 in a detachable manner. In addition, the reference numeral 31 in Fig. 3
Reference numeral 8.31b is an engaging portion that determines the position between the support ring 27 and the base 11.

As shown in FIG. 3, on the outer periphery of the frame 28 are positioning guides 32, 32 and upper sabots 1 34...
is provided. The positioning guide 32 32 is fitted and guided by the kite rod 33 33 on the inner surface of the reactor pressure vessel 1, and positions the entire closure device 10 in the circumferential direction, that is, the closure plug 15 for the main steam nozzle 3 .
・It is designed to position the insertion/extraction direction. Also,
As shown in FIG. 4, the 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. When the upper support 35 is engaged with the dryer support bracket 35, the closing plugs 15 are positioned in the height direction with respect to the main steam nozzles 3. The dryer support brackets 35 are used to support a steam dryer (not shown) during operation of the nuclear reactor.

Also, inside the frame 28, as shown in FIG.
6... is provided. These lower supports 36.
. . . are normally housed within the frame 28, but are projected toward the dryer support bracket 35 . . . by hydraulic cylinders 37 . . . and can be engaged with the brackets 35 . And these lower supports 36
When engaged with the driver and ear support bracket 35, the support ring 27 is positioned in the height direction with respect to the main steam nozzle position. Further, within the frame 28, as shown in FIG. 2, pressing rods 38 are provided. These pressing rods 38 are located below the closing plugs 15, and can be pushed toward the inner surface of the reactor pressure vessel 1 by a hydraulic cylinder 39.

Further, as shown in FIG. 2, underwater lighting devices 40 are attached to the support ring 27 in a circumferential direction of the frame 28 and are removably attached to the support ring 27. It is designed to irradiate These underwater lighting devices 40... are attached to the frame 28 by hooking a hanging jig 41 as shown in FIGS. 5 and 6, and a hanging ear 418 is provided at the upper end of the hanging jig 41. There is. The lighting fixture main body 42 is attached to the lower end of the hanging jig 41. The lighting main body 42 is constructed by accommodating, for example, a plurality of halogen light bulbs 44 in a lamp case 43 made of plastic deck that is translucent and waterproof. Note that 45 is a socket for the halogen light bulb 44, 46 is a reflective shade for the halogen light bulb 44, and 47 is a protective wire mesh provided on the outer surface of the lamp case 43.

Further, 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 work floor 8 of the reactor building. and is connected to a power outlet. Note that 50 is a switch box.

Further, the lighting fixture main body 42 is rotatable about a pivot 51 in the hanging jig 41.

A disk 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 disk 52 at equal pitches on the circumference. . A setting lever 54 is attached to the disk 52 side, and the setting lever 54 has the engagement hole 53.
... is provided with a protrusion (not shown) that can be fitted into it. Therefore, the above-mentioned protrusion can be connected to any engagement hole 53...
By fitting into the lighting device body 42, 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 closure device 1o having the above configuration will be explained.

First, during periodic inspection, the entire device is assembled by attaching the blocking plug 15 and the support ring 27 to the base 11 on the work floor 8, and then lifting the blocking device 10 with an overhead crane. Then, the closure device 10 is transferred to the upper part of the reactor pressure vessel 1 by an overhead crane, and gradually inserted into the reactor pressure vessel 1. At this time, the positioning guide 32.32 is fitted and guided by the guide rod 33.33, and the closure plug 1
5... is positioned in the circumferential direction.

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. I support it with 35... At this time, the blockage plug 1
5... and the main steam nozzle 3... face each other, and the blocking plug 15 is positioned in the height direction. After that, by operating the hydraulic cylinder 23...
The blockage plugs 15... are pushed out through the trolleys 22..., and the blockage plugs 15... are inserted into the respective main steam nozzles 3,
...Insert inside. In addition, at this time, the blocking plug 15.
... slides on the beam 13, 13 and is guided by the insertion guide 26... to be inserted. After the plug plugs 15 are inserted, as shown in FIG. 7, water and air are supplied into the hydraulic seals 18 and pneumatic seals 19, respectively.
Then, the pneumatic seal 19 is expanded, thereby air-tightly sealing the main steam nozzle 3 .

Next, the base 11 side is lifted, and the revolving 1-ring 27 is lifted to a position slightly above the main steam nozzle position. At this time, the connection between each blockage plug 15 and the carriage 22, that is, the engagement of the connectors 25a and 25b is performed by the base 11.
In other words, as the trolley 22 rises, it comes off and these connections are released. After this, the hydraulic cylinder 37...
After operating the lower supports 36 to protrude from the frame 28, the base 11 side is gradually suspended again. Then, the lower supports 36 are engaged with the dryer support brackets 35 as shown in FIG. 8, and the support ring 27 is installed on the dryer support brackets 35. This positions the support ring 27 at the main steam nozzle position. Also,
Press the rod 38 by operating the hydraulic cylinder 39...
... protrudes from the frame 28, and the blockage plug 15.
... is pressed and held as shown in FIG. After that, the hydraulic cylinders 30... are operated to pull out the connecting rods 29... from the frame 28 to release the connection between the support ring 27 and the base 11, and then the base 11 is lifted up and the reactor is removed. Remove from pressure vessel 1. At this time, the closing plugs 15 of the closing device 10 and the support ring 27 remain in the reactor pressure vessel 1, as shown in FIG. And next, support ring 27
Attach underwater lighting equipment 40... to.

In this way, the main steam nozzle 3... is blocked by the plug 15.
After sealing with..., attach the underwater lighting fixture 40... to the sabot i-ring 27, and then install the main steam isolation valve 6...
..., etc., and perform maintenance and inspection on them.
By applying steam pressure inside the main steam pipe 4...
Perform a leakage test on main steam isolation valve 6, etc. Note that even if steam pressure is applied inside the main steam pipe 4 at this time, the blocking plug 15 is pressed against the support ring 27 by the rod 38. Since the plugs 15 are held down by the protrusion 8 caused by the steam pressure, the plugs 15 are reliably prevented from popping out due to the steam pressure.

In parallel with this, during fuel exchange, the underwater lighting fixtures 40 attached to the support ring 27 are turned on to illuminate the entire interior of the reactor pressure vessel 1. As a result, from the working floor 8 to the vicinity of the reactor core 2? ! This improves visibility and improves the efficiency of fuel exchange. In addition, at the time of such fuel exchange, only the closing plug 15 of the closing device 10 and the support ring 27 are left in the reactor pressure vessel 1, as shown in FIG. It does not interfere with the fuel exchange work in any way. Furthermore, since the underwater lighting fixtures 40... are attached to the support ring 27, there is no need to suspend the underwater lighting fixtures each time a fuel assembly is handled, as is the case in the past. The entire area inside the reactor pressure vessel 1 can be reliably and stably illuminated without shaking, and the illumination effect is high. Furthermore, unlike in the past, the water surface of the reactor well 9 does not sway due to the swinging of the hanging wire due to the shaking of the underwater lighting equipment, so the inside of the reactor from the work floor 8 can be easily seen.
! It can further improve recognition.

Furthermore, by attaching the underwater lighting fixtures 40 to the base 11, it is possible to save time in handling the underwater lighting fixtures 4o, compared to conventional hanging and hanging type ones, and also to save fuel handling time. Since there is no need to lift and lower underwater lighting equipment during work, periodic inspection periods can be shortened, and the amount of radiation exposure for workers can be significantly reduced.

[Effects of the Invention] As explained above, the present invention includes a blockage plug that is detachably inserted into a main steam nozzle and seals the main steam nozzle air-tightly, and a blockage plug that is installed at the main steam nozzle position after insertion of the blockage plug. Positioned along the inner peripheral surface of the reactor pressure vessel 1
The reactor pressure vessel is characterized by comprising a ring-shaped support ring that prevents the plug from popping out into the reactor pressure vessel, and a plurality of underwater lighting fixtures attached to the support ring along the circumferential direction. It is. Therefore, according to the present invention, the underwater lighting equipment does not shake during fuel exchange IR work, and the water surface does not shake due to the shaking of the underwater lighting equipment, so the entire area inside the reactor pressure vessel is reliably and stably maintained. It is possible to improve visibility inside the reactor pressure vessel. In addition, the effects are significant, such as reducing the amount of stress on workers and improving the operating rate of the reactor.

[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 line IV-IV in FIG. 3, FIG. 5 is a sectional view taken along line V-V in FIG. 3, and FIG. 6 is a sectional view taken along line V-IV in FIG.
- A sectional view taken along the line Vl, FIG. 7 is a view immediately after the plug is inserted into the main steam nozzle, FIG. 8 is a sectional view of the support ring when the lower support is protruding, and FIG. 9 is a sectional view of the support ring when it is pressed (
FIG. 110 is a cross-sectional view of the reactor pressure vessel with the base removed when the plug is inserted. 1... Reactor pressure vessel, 3... Main steam nozzle, 15
...Support ring, 40...Underwater lighting equipment, 41.
...Hanging jig. Figure 10)

Claims (1)

[Claims] (1) A blockage 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 a reactor at the main steam nozzle position after insertion of the blockage plug. A ring-shaped support ring that is positioned on the inner circumferential surface of the pressure vessel to prevent a blockage plug from popping out into the reactor pressure vessel, and a plurality of underwater lighting fixtures that are attached to the support ring along the circumferential direction. r of a nuclear reactor main steam nozzle characterized by comprising:
J1 blockage device. (21) The nuclear reactor main steam nozzle closing device according to claim 1, wherein the underwater lighting device is detachably attached to a support ring.