JP3296389B2 - Reactor cleaning equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cleaning apparatus suitable for cleaning the inside of a boiling water reactor (hereinafter referred to as "BWR") during periodic inspection or the like.

[0002]

2. Description of the Related Art Generally, a BWR incorporates a cylindrical shroud 2, a steam separator 3, a dryer 4 and the like in a cylindrical reactor pressure vessel 1 together with reactor water as shown in FIG. A plurality of fuel assemblies 5 are loaded into the shroud 2 while a plurality of control rods 6 are inserted or withdrawn. The upper and lower ends of the fuel assembly 5 are supported by an upper lattice plate 7 and a core support plate 8, respectively.

[0003] Under the annular gap between the inner peripheral surface of the cylindrical reactor pressure vessel 1 and the outer peripheral surface of the shroud 2, an annular baffle plate 9 is provided in a watertight manner as shown in FIG. 7. 8 on the baffle plate 9.
However, as shown in the figure, a plurality of jet pumps 10, 10...

Each jet pump 10 is connected to a discharge port of a recirculation pump (not shown) installed outside the reactor pressure vessel 1 via a water pipe 11, and receives water from the recirculation pump to enter the reactor water. It discharges at a predetermined pressure to generate a recirculating flow in the furnace, and a plurality of sensing lines 12 for measuring the flow rate are arranged around the jet pump 10.

In FIG. 7, reference numeral 13 denotes a water supply nozzle, in FIG. 6, 14 denotes a pressure vessel cover, 15 denotes a shroud head, 16 denotes a shroud support, 17 denotes a control rod guide tube,
Reference numeral 18 denotes a control rod drive mechanism housing.

When the reactor pressure vessel 1 constructed as described above is refurbished in the reactor or the like, floating dust or the like usually accumulates on the baffle plate 9. The plate 9 is being cleaned.

In the conventional cleaning method, first, a submersible pump is poured into the reactor water in the reactor pressure vessel 1 and is seated and suspended in the stepped portion thereof. The reactor water containing dust and the like is suctioned in the vicinity, and the suction water is filtered by a filter detachably provided in the submersible pump to capture and remove dust and other foreign matter, and then discharged into the reactor pressure vessel 1 again. The reactor water is cleaned and the baffle plate 9 is mainly cleaned.

[0008]

However, the baffle plate 9 is located at a depth of about 20 m from the upper part of the reactor pressure vessel 1 and has an inner peripheral surface of the reactor pressure vessel 1 and an outer peripheral face of the shroud 2. And a plurality of jet pumps 10, water pipes 11, sensing lines 12, and the like are arranged in the narrow annular gap at predetermined intervals in the circumferential direction. So
Very narrow and in a dark place.

When the suction hose is moved in the reactor pressure vessel 1, the suspension rope and the operation pole are manually operated from the reactor, but the movement is very difficult. Positioning accuracy is low, consuming a great deal of labor and time, and mechanization is eagerly desired.

Accordingly, the present invention has been made in view of such circumstances, and has as its object to provide high accuracy of positioning of a cleaning portion and to easily perform cleaning in a furnace such as a baffle plate by remote control from the furnace. It is an object of the present invention to provide a reactor cleaning apparatus that can be performed quickly.

[0011]

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and has the following structure.

According to a first aspect of the present invention, there is provided an operation pole which is suspended in a reactor having built-in reactor water and a plurality of jet pumps so as to be able to ascend and descend, and the suspension tip is branched into a plurality of branches. A crown portion attached to one branch end of the operation pole and detachably and rotatably fitted to the outer periphery of the head of the jet pump; and connected to the other branch end of the operation pole. And a support pole for vertically and rotatably providing a support portion for supporting the tip of the suction port of the suction hose for sucking the reactor water.

Further, the invention according to claim 2 of the present application is characterized in that the operation pole is configured to be rotatable around the axis by the refueling machine.

Further, the invention described in claim 3 of the present application is:
The suction hose is connected to a suction port of a pump, and the pump is configured so that a filter for filtering suction water is detachably provided and clean water filtered by the filter is returned to the reactor. I do.

Further, the invention according to claim 4 of the present application is characterized in that the suction hose is provided with a check valve which opens the water absorption passage only when the reactor water is sucked, and closes the water absorption passage when the suction is stopped. It is characterized by being.

The invention according to claim 5 of the present application is characterized in that the support pole supports the suction hose via a watertight box in which a plurality of small hoses are juxtaposed. .

[0017]

[Operation] When an operation pole is suspended in a nuclear reactor, and the capping part of one branch end is fitted to an arbitrary jet pump head, a support pole supporting a suction hose is positioned on a baffle plate. I do.

Next, when the operation pole is rotated around the axis, the support pole at the other branch end rotates around the axis of the crown portion around the axis. The suction tip opening of the suction hose supported by the support rotates.

Therefore, the position of the suction tip opening of the suction hose can be more finely adjusted by further vertically moving or rotating the suction hose support, so that the positioning accuracy of the suction hose can be improved.

Next, by operating the submersible pump, furnace water containing dust and the like on the baffle plate is sucked from the suction hose, and the suction water is filtered by a filter to remove purified water from the furnace again. By recirculating to the baffle plate, foreign substances such as suspended matter on the baffle plate can be removed and cleaned. At this time, by appropriately combining the rotation of the suction hose support portion and the rotation of the crown portion, almost the periphery of the jet pump can be cleaned.

Thereafter, the operation pole is slightly lifted,
After removing the capping part from the head of the jet pump, the capping part is fitted over the head of the jet pump in the vicinity of the next part to be cleaned next, and the above operation is repeated. On the baffle plate around the jet pump can be easily and quickly cleaned. By repeating this, the inside of the furnace such as the whole on the baffle plate can be cleaned.

When the suction hose is provided with a check valve, the suction water containing the dust and the like once sucked by the suction hose is returned to the furnace water again when the suction is stopped to prevent the reactor water from being contaminated. can do.

Further, when an underwater lighting device and an underwater camera are provided on the support pole portion of the operation pole, cleaning of the inside of the furnace can be remotely controlled while monitoring the inside of the furnace with a monitor. Cleaning can be performed more accurately, easily and quickly.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. 1 to 8, the same or corresponding parts are denoted by the same reference numerals.

FIG. 1 is a partially cutaway overall configuration view of an embodiment of the present invention, and FIG. 2 is a vertical sectional view of a lower portion thereof. An operation pole 24 of an arbitrary length is formed by connecting the columnar pole 22 detachably and concentrically by a pole joint 23.

The operating pole 24 has its upper end suspended or suspended from the reactor pressure vessel 1 by a fuel exchanger (not shown), and is suspended rotatably around its axis. 1 is formed as a U-shaped branch pole 25 that branches into two branches.

The branch pole 25 has a flat cylindrical capping part 26 at one end 25a of the U-shaped branch part and a straight cylindrical support pole 2 at the other branch end 25b.
7 are detachably and concentrically connected by an upper pole joint 28.

As shown in FIG. 4, the crowned portion 26 having a flat cylindrical shape with a cover is provided with a slight play in the diameter direction on the head of the jet pump 10 (see FIGS. 6 to 8) provided with the gripping grapple 10a. And acts as a rotation fulcrum at the time of positioning the cleaning portion.

On the other hand, the lower end of the support pole 27 in FIG. 1 is connected to a lower pole joint 29 as shown in FIG.
And are connected concentrically.

The operating cylinder 30 has a cylindrical guide tube 31 slidably fitted on its outer periphery in the axial direction so as to be slidable in the axial direction. The lower end 31a of the guide tube 31 in FIG. The lower end of the piston shaft 32 which reciprocates in the axial direction is fixed by screw connection.
In FIG. 2, the extension ports 3 respectively drilled at the lower end portion
A hose (not shown) is connected to each of the contraction port 3 and the contraction port 34 so as to supply air or water at a predetermined pressure. Each hose is connected to a compressed air or water supply (not shown) on the furnace. Also, while a pin is protrudingly provided on the outer surface of the operation cylinder 30, a slit into which the pin is fitted is formed in the axial direction of the guide cylinder 31, and the guide cylinder 31 is guided by the slit and the pin to extend in the axial direction. To slide.

The guide cylinder 31 has a lower flange 31a.
Further, a cylindrical frame 35 is concentrically fixed thereto, and a motor 36 is built in the frame 35. The motor 36 is
The rotating shaft 36a is rotatably supported by a double-row bearing 37, while the tip (the lower end in FIG. 2) of the rotating shaft 36a.
In addition, an end cap 38 that closes the lower end of the opening of the frame 35 in a watertight manner is penetrated in a watertight manner, and is then fixed concentrically to the disk 39.
The watertight box 41 is concentrically connected to the watertight box 41 with bolts and nuts.

The watertight box 41 has a plurality of manifold tubes 42 buried in a lower surface thereof so as to communicate with each other.
Inverted L-shaped connection pipe 4 protruding from one side of one to be freely communicable
The opening tip of the suction hose 44 is watertightly fitted into and connected to the tip of the opening 3.

The suction hose 44 is connected to a suction port of a submersible pump (not shown) immersed in the reactor water in the reactor pressure vessel 1, and the submersible pump has a filter (not shown) for filtering the suction water, which is detachably mounted. And discharges the filtered clean water into the furnace water again.

As shown in FIG. 1, an underwater lighting device 46 for illuminating the inside of the reactor water is mounted on the outer surface of the guide tube 31, and an underwater video camera 47 is attached to the lower end of the frame 20 at the lower part in FIG. Is mounted, and the underwater video camera 47 is electrically connected to a monitor (not shown) on the reactor pressure vessel 1 so that an image in the reactor pressure vessel 1 can be monitored by the monitor.

The suction tip of the suction hose 44 is shown in FIG.
As shown in (1), the support arm 45 may be directly connected to the support 40 without connecting to the watertight box 41.

Further, the tip of the opening of the suction hose 44 (FIG. 2)
(In the lower end portion), a check valve 48 may be mounted as shown in FIG. The check valve 48 is opened when the suction hose 44 is sucking the reactor water, closed when the reactor water is stopped, and the dirty reactor water containing dust and the like once sucked in is discharged again into the reactor pressure vessel 1.
This prevents the water from flowing back into the reactor and contaminating the reactor water.

That is, the check valve 48 has a hollow shaft 50 concentrically incorporated in a body 49 which is water-tightly connected to the distal end of the suction hose 44 by a joint 48a.
3 is fixed to the upper end in the body 49.

The hollow shaft 50 is located in the body 49 in FIG.
A small hole 51 penetrating in the diameter direction is formed at the middle upper end portion, and a suction hole 52 penetrating the diameter direction is formed at the outer end portion extending from the lower end of the opening of the body 49 to the outside. 50
A sliding cylinder 53 is externally slidably fitted on the outer periphery of the cylinder.

The sliding cylinder 53 has an annular stopper projection 53a projecting from the lower periphery thereof, and an end cap 54 screwed to the outer periphery of the lower end of the opening of the body 49. Withdrawal from 49 is prevented.

The sliding cylinder 53 has a through hole 53b formed in the upper end thereof, which penetrates in the diameter direction.
3b, the hollow shaft 5 is moved when the sliding cylinder 53 moves to the top dead center.
It communicates with the small hole 51 of zero. The stopper projection 53a is provided on the outer periphery of the sliding cylinder 53.
And a coiled spring 55 between the upper end of the inner wall of the body 49
The outer surface of the suction hole 52 of the hollow shaft 50 is always closed by the sliding cylinder 53 by constantly biasing the sliding cylinder 53 downward in the figure by the spring 55. Reference numeral 56 in FIG. 3 denotes a plug for closing the bottom opening 50a of the hollow shaft 50.

Next, a description will be given of a method of using the thus-constructed reactor cleaning apparatus 21.

At the time of periodic inspection of the reactor, the pressure vessel cover 14, the dryer 4, the steam separator 3, and the shroud head 15 are respectively removed from the main body of the reactor pressure vessel 1 shown in FIG.

Therefore, after moving the fuel assembly 5 to a storage pool or the like, the plurality of poles 22 shown in FIG. 1 are sequentially connected on the reactor pressure vessel 1 to adjust the operation pole 24 to a required length. At the same time, the distal end of the suction opening of the suction hose 44 connected to the submersible pump is attached to the support 40 of the support pole 27 by the support arm 45, and then suspended by a fuel exchanger (not shown) so that the inner circumference of the reactor pressure vessel 1 is Suspended in the annular gap between the surface and the outer peripheral surface of the shroud 2,
An unillustrated submersible pump is also suspended in the reactor water in the reactor pressure vessel 1.

Then, the operating pole 24 is appropriately operated to
When the crown portion 26 is fitted on the head of the jet pump 10 with play from the grapple 10 a, the lower end of the support pole 27 approaches the baffle plate 9. The periphery of the support pole 27 in the furnace is illuminated by the underwater lighting device 46 and photographed by the underwater video camera 47, so that it can be monitored by a monitor on a refueling machine (not shown) on the furnace.

When the operation pole 24 is rotated around the axis by a required angle while watching the monitor, the crown portion 26 slides around the axis on the grapple 10a of the jet pump 10.

For this purpose, the support pole 27 supporting the opening end of the suction hose 44 is swung around the axis of the crown portion 26 as shown in FIG. The motor 36 is operated by remote control from the refueling machine on the furnace to move the guide tube 31 up and down as needed, or rotate the disk 39 to rotate the suction tip of the suction hose 44 as needed to perform positioning.

Thereafter, when the submersible pump (not shown) is operated by remote control, the reactor water containing dust and the like on the baffle plate 9 is sucked by the suction hose 44, and the suction water is filtered by the filter of the submersible pump. After that, it is discharged again into the reactor pressure vessel 1 as clean water. Also,
The tip of the suction hose 44 is rotated around the support pole 27 by the operation of the motor 36, and the support pole 27 is swung around the jet pump 10 by rotation about the axis of the operation pole 24. Can be cleaned.

After cleaning around the jet pump 10, the operation pole 24 is slightly lifted to remove the crown portion 26 from the head of the jet pump 10, and the jet pump in the vicinity of the portion to be cleaned next The operation pole 24 is again suspended in the furnace so that the crown portion 26 is fitted over the head of the apparatus 10, and the above operation is repeated. As described above, the suction hose 44 sucks turbid water containing dust and the like in the reactor pressure vessel 1 and returns clean water into the reactor pressure vessel 1, whereby the entire surface of the baffle plate 9 can be cleaned.

Therefore, the inside of the reactor pressure vessel 1 can be easily and quickly cleaned even in a narrow and dark place in the reactor pressure vessel 1.

When a check valve 48 is attached to the suction hose 44, the suction passage can be closed when the suction hose 24 stops sucking the reactor water, so that the dirty suction water sucked up to that point is again removed. It is possible to prevent backflow into the reactor pressure vessel 1 and contaminate the interior of the reactor pressure vessel 1.

That is, when the suction hose 44 starts suction of the reactor water, the differential pressure between the suction negative pressure and the reactor water pressure passes through the small hole 51 of the hollow shaft 50 shown in FIG.
3 acts on the accommodation space above, so that the sliding cylinder 53 is
3 is pushed upwards in FIG. 3 against the spring force of 5, and the through-hole 53b of the sliding cylinder 53 is in communication with the small hole 51 of the hollow shaft 50 so as to communicate therewith. The push-up position is maintained.

For this reason, the outside of the suction hole 52 of the hollow shaft 50 is released and exposed and opens in the furnace water, so that the reactor water is sucked into the hollow shaft 50 from the suction hole 52 and further the suction hose 44 And suction of reactor water containing dust and the like is started.

On the other hand, when the suction of the suction hose 44 is stopped, the differential pressure between the suction negative pressure and the reactor water pressure no longer acts on the sliding cylinder 53, and as shown in FIG. The moving cylinder 53 is pushed downward in the figure, and the outside of the suction hole 52 of the hollow shaft 50 is closed by the sliding cylinder 53. Thus, the reactor water containing dust and the like that has been sucked into the hollow shaft 50 so far is removed. From the reactor to the reactor pressure vessel 1 to prevent contamination.

As shown in FIG. 2, when the watertight box 41 is mounted on the support 40, the reactor water containing dust and the like in the reactor pressure vessel 1 is sucked by the manifold hose 42, and the water inside the watertight box 41 is removed. Through the suction hose 44.

[0055]

As described above, according to the present invention, the reactor water containing dust and the like is sucked by the suction hose, and the clean water filtered by the filter or the like is returned to the reactor again, so that the inside of the reactor is made safe. It can be cleaned easily and quickly.

Further, the support pole for supporting the suction hose can be rotated around the crown of the operation pole, and the vertical movement and rotation of the suction hose can be appropriately controlled by the support pole. Has a high positioning accuracy and a large moving range. For this reason, the cleaning range by the suction hose can be expanded, and the positioning accuracy of the cleaning portion can be improved.

When a check valve is provided in the suction hose, it is necessary to prevent dirty water containing dust and the like once sucked by the suction hose from flowing back into the water when the suction is stopped to contaminate the water. Can be prevented.

Further, when the underwater lighting device and the underwater camera are provided on the support pole of the operation pole, the inside of the furnace can be remotely controlled while monitoring the inside of the furnace with a monitor. Can be performed more easily and quickly.

[Brief description of the drawings]

FIG. 1 is a partially cutaway front view of one embodiment of a reactor cleaning apparatus according to the present invention.

FIG. 2 is a partially enlarged longitudinal sectional view of the embodiment shown in FIG. 1;

FIG. 3 is a vertical sectional view of a check valve attached to the suction hose shown in FIG. 1;

FIG. 4 is a view taken along the line IV-IV in FIG. 1;

FIG. 5 is a bottom view of FIG. 3;

FIG. 6 is a longitudinal sectional view showing a general configuration of a boiling water reactor.

FIG. 7 is a sectional view taken along line VII-VII of FIG. 6;

FIG. 8 is a partially omitted front view of the plurality of jet pumps shown in FIGS. 6 and 7;

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 reactor pressure vessel 2 shroud 3 steam separator 4 dryer 5 fuel assembly 6 control rod 7 upper grid plate 8 core support plate 9 baffle plate 10 jet pump 11 water pipe 14 pressure vessel cover 21 reactor cleaning device 22 pole 23 Pin Joint 24 Operation Pole 25 Branch Pole 26 Crown Part 27 Support Pole 30 Cylinder 31 Guide Tube 32 Piston Shaft 35 Frame 36 Motor 37 Double Row Bearing 38 End Cap 39 Disk 40 Support 41 Watertight Box 42 Various Hose 44 Suction Hose 45 Support arm

Continuation of the front page (56) References JP-A-58-131593 (JP, A) JP-A-57-3088 (JP, A) JP-A-53-1968 (JP, A) JP-A-59-216099 (JP, A) , A) JP-A-8-18493 (JP, A) JP-A-7-280987 (JP, A) JP-A-58-129399 (JP, A) JP-A-51-105595 (JP, A) 62-128399 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) G21C 19/02 G21F 9/28 B08B 3/08

Claims (5)

(57) [Claims] 1. An operation pole suspended in a reactor containing reactor water and a plurality of jet pumps so as to be able to move up and down, and the suspension tip is branched into a plurality of branches, and one branch end of the operation pole. And a capping part which is attached to the outer periphery of the head of the jet pump so as to be detachably and rotatably fitted thereto, and which is connected to the other branch end of the operation pole to suction the reactor water. A reactor inside a reactor, comprising: a support pole for vertically and rotatably providing a support portion for supporting a tip end of a suction port of a hose. 2. The reactor cleaning apparatus according to claim 1, wherein the operation pole is configured to be rotatable around an axis by a refueling machine. 3. A suction hose is connected to a suction port of a pump. The pump has a structure in which a filter for filtering suction water is detachably provided, and clean water filtered by the filter is returned to the reactor. 3. The cleaning apparatus in a nuclear reactor according to claim 1, wherein: 4. The suction hose according to claim 1, wherein the suction hose opens a water absorption passage only when the reactor water is sucked, and has a check valve which closes the water absorption passage when the suction is stopped. The reactor cleaning device according to any one of the preceding claims. 5. The supporting pole according to claim 1, wherein the supporting portion supports the suction hose via a watertight box in which a plurality of small hoses are juxtaposed. A cleaning device in a nuclear reactor according to the above.