JP2903963B2 - Pipe decontamination equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the removal / decontamination of solidified radioactive deposits in primary piping / equipment and auxiliary equipment of a nuclear reactor of a nuclear power plant, and to reduce the dose equivalent rate of piping and equipment. Also, the present invention relates to a technology for removing radioactive deposits that is optimal for reducing exposure dose equivalents, such as maintenance work of a regular inspection plant.

[0002]

2. Description of the Related Art A conventional method of removing radioactive deposits is a method in which electrolytic polishing is performed to remove the radioactive deposits from the inner surface of a pipe, and the portions are forcibly peeled off by brushing.

[0003] The principle of electrolytic polishing is to set an electrode in a pipe to be decontaminated and then flow an electrolytic solution therethrough. Next, after configuring and adjusting the characteristic electrode (negative) so that the inner surface of the pipe to be decontaminated becomes the anode, the radioactive substances adhering to the inner surface (anode side) of the pipe to be decontaminated are decomposed and separated by an electrical chemical reaction. It is to let.

[0004] The structure and function of a polishing apparatus for adopting the conventional method of removing radioactive deposits will be described below.

The structure of the polishing apparatus used in the conventional removing method is composed of a core material, a brush, an insulating brush support and the like which constitute a cathode member in electrolytic polishing.

At the time of decontamination, a pipe to be decontaminated is set upright on a watertight fixing jig, filled with an electrolyte such as sulfuric acid, and inserted into a decontamination apparatus.

At this time, radioactive deposits have been removed by performing electrolytic polishing using the pipe to be decontaminated as an anode and the core material as a cathode, then rotating the polishing apparatus through a shaft, and brushing the inner surface of the pipe to be decontaminated. .

[0008] Therefore, the conventional method for removing radioactive deposits has been limited in practical application to a nuclear power plant due to the following reasons, and has been difficult to use widely.

It can be applied only to piping / equipment to be disassembled in piping / equipment with a high dose equivalent, and it is extremely difficult to apply it to piping or the like in a state where the actual equipment is installed.

[0010] In order to decontaminate the piping system, the mounting posture is in a fixed direction, and it has been difficult to apply the piping system of a power plant to a complicated shape.

[0011] A shaft for rotating the decontamination apparatus is provided, and the length and shape of the shaft are limited, so that the shape and size of the pipes and equipment to be decontaminated are limited, so the application is very limited. It had been.

At the time of decontamination, the object to be decontaminated needs to be decomposed, taken out and moved, and the time required for preparatory work for decontamination and the exposure dose are extremely increased, and compared with the reduction effect by decontamination, There is a drawback that the effect cannot be obtained so much when attention is paid to a special effect.

[0013] It is necessary to replace the electrolyte several times in order to obtain a specific effect by immersing the electrolyte in the electrolyte, and the size and range of the object to be decontaminated are limited due to the amount of the electrolyte used. There was a problem.

[0014] Furthermore, the used electrolyte (waste liquid) contains extremely radioactive deposits, and it is difficult to treat it.

In electrolytic polishing or the like, the removal amount is not constant because the removal is performed by an electric action, and it is considered necessary to consider the quality.

[0016]

In the above prior art, no consideration is given to the application of the primary reactor system and auxiliary equipment (piping and equipment) in the installed state and the application to a wide range of piping and the like. In addition, since the electrolytic solution is used, there is a limit to the object to be decontaminated from the usage amount and the like, and there is room for improvement when considering the application to an actual machine.

An object of the present invention, and the like enables the cladding removed remains actual installation state pipe, it is possible to reduce the surface dose equivalent rate of the piping and equipment, greatly reduce the exposure dose during the plant outage Plumbing decontamination equipment
To provide a location .

[0018]

[MEANS FOR SOLVING THE PROBLEMS] To achieve the above object
A first aspect of the present invention relates to a primary reactor system of a nuclear power plant.
Mechanical removal of oxides containing radioactive substances adhering to the inner surface of the pipe
Work to perform decontamination work in the pipe decontamination equipment to be removed
Part body and movement for moving the working part body in the pipe axis direction
Open the transmitter and the equipment attached to the piping to be decontaminated.
Installed on the outside of the narrow space
A moving force generator for applying, and
Work power installed to generate work power for the work unit body
Generator and the working power generated by the working power generator
A work power transmission body for transmitting the work power to the work unit main body.
The business unit main body, the work power transmission body and the movement transmission body,
It is configured to be insertable into the pipe from the narrow space,
The dynamic transmission element consists of a chain of multiple rectangular link elements,
The element can be bent in one direction.
The upper part is pinned to each other and the lower part of the rectangular link
There is a roller installed on the inside of the pipe that moves in the pipe axis direction.
You. A second invention for achieving the above object is a nuclear power plant.
Radioactive substances adhering to the inner surface of the primary piping of a nuclear power plant
In pipe decontamination equipment that mechanically removes oxides containing impurities
A working unit body for performing decontamination work, and the working unit body
For moving transmitters that move in the pipe axis direction and piping to be decontaminated
Installed outside the narrow space where the attached equipment is open
Generating a moving force for applying a moving force to the moving transmission body.
Body and the working unit body installed outside the narrow space
A work power generator for generating work power, and the work power generator
Work for transmitting work power generated by the body to the work unit body
A power transmission body, the work unit main body, the work power transmission
The moving body and the movement transmitting body are placed in the pipe from the narrow space.
The work power transmission body is configured to be insertable.
Work power is transmitted to the work unit body via the inside of the transmission body.
Reach.

[0019]

According to the present invention, the working unit body and the working power transmission body are provided.
And the mobile communicator to the equipment attached to the piping to be decontaminated.
It is designed so that it can be inserted into piping from an open narrow space.
With this, the cladding is removed while the piping etc. are installed in the actual machine
Becomes possible. Preparation work related to decontamination work
Time and exposure dose can be reduced. Also move
Drive the transmission body to move the work unit body in the pipe axis direction
This greatly increases the scope of decontamination of piping,
And the surface dose equivalent rate of equipment and equipment can be reduced. In addition, external
Decontamination using the moving power generator and the work power generator
Work can be operated remotely, so decontamination during regular plant inspections
The radiation dose to such workers can be significantly reduced.

[0020]

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the embodiments shown in the accompanying drawings.

FIG. 1 shows the application of the first embodiment of the pipe decontamination apparatus according to the present invention to a reactor coolant recirculation pipe (hereinafter abbreviated as PLR pipe) of a reactor primary pipe in a BWR power plant. It is a perspective view.

In FIG. 1, a PLR pipe 1 is a pipe system for forcibly circulating a coolant in the RPV 2 in order to enhance a cooling effect of the fuel in the RPV 2. 4, flows into the pipe, is pressurized by the PLR pump 5 via the valve 8,
RP again from jet pump 7 via LR inlet nozzle 6
Return to V2.

For this reason, in the reactor coolant recirculation pipe, radioactive deposits tend to accumulate on the innermost surface (in proportion to the number of years of plant operation) in a nuclear power plant, and as a result, the surface dose equivalent rate increases. There is a concern that the dose equivalent of workers will increase during the periodic inspections conducted every year. Therefore, it is considered necessary to make efforts to reduce the dose equivalent rate of high dose equivalent rate piping and equipment as a countermeasure.

Referring to FIG. 1, the pipe decontamination apparatus according to the present embodiment includes a working unit body 10 for performing a decontamination operation, a moving transmission body 11 for moving the working unit body 10 in the pipe axial direction, and a moving transmission body. A moving force generator 13 for applying force;
Work power transmission body 12 for applying power to work section main body 10
And the working power generator 14 as a basic configuration.
It comprises a control panel 15.

Of these, the working unit body 10 and the moving transmission body 1
1, the work power transmission body 12 is inserted into a pipe from a narrow space where a valve 8 attached to a system of a pipe to be decontaminated is opened to perform a work.

FIG. 2 is a schematic diagram showing a state in which the valve 8 of the pipe decontamination apparatus according to the first embodiment of the present invention is inserted from a narrow space. The working unit main body 10 and the working power transmission body 12 are connected and then inserted, the movement transmission body 11 is connected near the insertion location, and the moving force installed on the flange surface 17 of the valve 8 outside the open narrow space 16. The moving force is transmitted to the pins 19 of the components of the movement transmitting body 11 by the sprocket 18 attached to the generator 13. In addition, work power is applied from a work power generator 14 (not shown) to the work power transmission body 12.

As a result, the working unit main body 10 is moved by moving the moving transmission body 11 forward (backward) while decontaminating the inner surface of the pipe 1, thereby continuously decontaminating the entire work area.

The moving transmission body 12 has a rectangular link 43.
The upper side of the rectangular link is connected to each other by a pin 19 so that each element can bend only in one direction. The lower link of the rectangular body guides the inner surface of the pipe in the axial direction of the pipe. Roller 36 is installed, and the dimension in the tube axis traveling direction is set to be equal to or less than the dimension of the narrow space where the valve or the like is opened, and the guide plate 41 is moved to the lower portion of the narrow space 16 of the valve 8 to smoothly advance. It is installed in the part.

FIG. 3 is a schematic sectional view showing details of the working unit body 10 according to the first embodiment of the present invention. FIG. 4 is a sectional view of the working unit body 10 according to the first embodiment of the present invention in FIG. FIG. 5 is a cross-sectional view of the working unit main body 10 according to the first embodiment of the present invention in FIG.

In these figures, the same components as those in FIG. 2 are the same components.

In FIG. 3, the working unit main body 10 includes a grindstone 20.
Polishing unit 23 comprising a grinding wheel rotation actuator 21 and a grinding wheel pressure contact actuator 22, a cleaning unit 24 for spraying high pressure water toward the inner surface of the pipe, a driving unit 25 for rotating the polishing unit, and at equal intervals from the outer periphery of the driving unit. An alignment unit 26 for automatically aligning the working unit main body by pressing the inner surface of the pipe with a constant pressing force, and a connecting means 27 for connecting the movement transmitting body 11 are provided.

In this embodiment, the grinding wheel rotating actuator 21
Is, for example, an air motor, the grinding wheel pressure contact actuator 22 is an air cylinder, one of the working power transmitting bodies 12 is an air hose, and one of the working power generating bodies 14 is an air source. The air pressure from the air source 14 is
One is guided to the inside of the centering portion 26 via a rotary joint 28 provided for improving the insertability.

As a result, the centering air cylinder 29 of the centering section 26 is pressurized, and the two pressing rollers 30 move forward to press the inner surface of the pipe 1 (not shown). It is measured by the displacement meter 31.

In this embodiment, the centering air cylinder 2
9, three sets of centering elements of the pressure roller 30, and the displacement meter 31 are arranged at equal intervals in the circumferential direction of the pipe, and the pressing force of each air cylinder 29 for centering is constant. The entire body 10 is automatically aligned with the axis of the pipe 1 (not shown).

From the difference between the value of each displacement meter 31 and the diameter of the pipe at the time of construction, the thickness of the radioactive substance deposited is calculated as the removal thickness by the operation / control panel 15 installed outside the pipe. The other of the air pressure supplied through the rotary joint 28 is the polishing unit 2
The rotation guide 3 is guided to the rotation shaft 33 via the fixed shaft 32 which also serves as a rotation support and an air source transmission as a working power.

From here, air is supplied to the air motor 21 to rotate the grindstone 20 and the rotation of the air motor of the drive unit 25 causes the entire polishing unit 23 to rotate. The operation / control panel 15 controls the rotation of the polishing section 23 based on the relationship between the removal thickness and the removal amount per unit rotation, and removes a radioactive substance having a predetermined thickness.

As shown in FIG. 4, three sets of the grindstone 20, the air motor 21 and the air cylinder 22 are arranged at equal intervals, and the grindstone 20 is pressed against the inner surface of the pipe by the air cylinder 22 with a constant pressing force. This enables uniform decontamination.

A cleaning unit 24 is incorporated inside the polishing unit 23, and is connected via a high-pressure water pump (not shown), a high-pressure hose of the working power transmission unit 12, and a rotary joint 28 (not shown). High pressure water is supplied.

As shown in FIG. 5, high-pressure water nozzles 35 are arranged at equal intervals on the periphery of the ring body 34 so that the radioactive material is removed and washed away.

FIG. 6 is a sectional view of the working power transmitting body 12 according to the first embodiment of the present invention taken along line CC of FIG. As described above, the movement transmitting body 12 has the upper side of the rectangular link connected to the pin 19 so that each element can bend in only one direction.
A roller 36 is provided at the lower link of the rectangular parallelepiped for guiding the inner surface of the pipe in the axial direction of the pipe.

In this embodiment, as shown in the figure, both sides of the rectangular cross section are constituted by plates 37 and 38, and the upper and lower sides are opened by pins 19 and a shaft 39.

In particular, the sprocket 18 attached to the moving force generator 13 enters the upper open space, and drives the pin 19 to move the moving transmitter 12 back and forth.

FIG. 7 is a schematic sectional view showing a state in which the working unit body 10 according to the first embodiment of the present invention is inserted into a pipe from a narrow space where the valve 8 is opened, and FIG. FIG. 3 is a schematic cross-sectional view illustrating a connection state between a working unit main body 10 and a movement transmitting body 11 according to the first embodiment.

In FIG. 7, after the work power transmitting body 12 is connected to the work unit main body 10, it is clamped by the work body main body insertion jig 40 and inserted and lowered from the narrow space 16 in which the valve 8 is opened. (Left side in the figure)
The work power transmission body 12 is put on standby to be connected.

In FIG. 8, some elements (six elements in FIG. 8) of the moving transmission body 11 are suspended while passing through the working power transmission body 12, and the connecting means 27 provided on the working unit main body 10 in a standby state. The pin 16 is positioned.

Further, both are connected by a connecting jig 41.

When the apparatus is carried out, the operation is reversed.

After the connection, the guide plate 41 is inserted as shown in FIG. 2, and the necessary equipment is installed.

In addition, the same operation and effect can be expected by using a pressurized tube internally reinforced as the movement transmitting body 11 and a friction type driving device as the moving force generator 13. Also,
In the above-described embodiment, the polishing unit 23 and the cleaning unit
Although the configuration is such that the part 24 is mounted, only the polishing part 23 is mounted.
After the polishing operation is performed, the cleaning unit 24 is replaced with a cleaning unit.
May be adopted.

With the above configuration and function, according to the embodiment of the present invention, there is provided a centering function from the conventional method for removing radioactive deposits, thereby defining a removal amount and accurately coping with mechanical polishing and high pressure. By combining jet cleaning, it is possible to remove radioactive deposits while the piping and equipment of the nuclear power plant are installed, leading to a significant reduction in exposure to maintenance work during plant periodic inspections. It is thought that it can greatly contribute to the safety and reliability of the power plant.

[0052]

According to the present invention, the piping and the like are installed in the actual machine.
Cladding can be removed as it is.
The surface dose equivalent rate can be reduced,
Exposure dose can be greatly reduced.

[0053]

[0054]

[0055]

[0056]

[Brief description of the drawings]

FIG. 1 is a perspective view showing an application of a first embodiment of a pipe decontamination apparatus according to the present invention.

FIG. 2 is a schematic diagram showing a state in which a valve 8 of the pipe decontamination apparatus according to the first embodiment is inserted from a narrow space.

FIG. 3 is a schematic sectional view showing details of a working unit main body 10 according to the first embodiment.

FIG. 4 is a view of the working unit body 10 according to the first embodiment of the present invention in FIG.

FIG. 5 is a sectional view of the working unit main body 10 according to the first embodiment of the present invention, taken along line BB in FIG. 3;

FIG. 6 shows the working power transmission body 12 according to the first embodiment, FIG.
10 is a sectional view taken along line CC in FIG.

FIG. 7 is a schematic cross-sectional view showing a state where the working unit body 10 according to the first embodiment is inserted into a pipe from a narrow space where the valve 8 is opened.

FIG. 8 is a schematic cross-sectional view showing a connection state between the working unit main body 10 and the movement transmitting body 11 according to the first embodiment.

[Explanation of symbols]

1 ... Reactor coolant recirculation pipe (PLR pipe), 8 ... Valve,
Reference numeral 10: working unit body, 11: moving transmission body, 12: working power transmission body, 13: moving power generation body, 14: working power generation body, 15: operation / control panel, 16: open narrow space,
Reference numeral 20: grinding wheel, 21: grinding wheel rotation actuator, 22: grinding wheel pressure contact actuator, 23: polishing section, 24: cleaning section,
25 ... drive unit, 26 ... alignment unit, 27 ... connection means, 19 ...
Pins, 36 ... rollers, 43 ... rectangular links.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI G21F 9/28 ZAB G21F 9/28 ZAB B08B 9/02 B08B 9/02 B (56) References Japanese Utility Model No. 4-102686 (JP) , U) Actual opening Sho 61-147999 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) G21F 9/28

Claims (3)

(57) [Claims] 1. A pipe decontamination apparatus for mechanically removing an oxide containing radioactive substances adhering to the primary reactor piping inner surface of the nuclear power plant, a working body to perform decontamination, the working unit Attached to the movement transmitter that moves the main unit in the pipe axis direction and the pipe to be decontaminated
Before being installed outside the narrow space where
Serial and moving force generator for applying a moving force to the moving transmission member, work of the working body is placed outside of the narrow space
Work power generator for generating work power, and the work power generator
A work power transmitting body for transmitting the working power generated in the above to the working unit main body , wherein the working unit main body, the working power transmitting body, and the movement transmission
The body is configured to be insertable into the pipe from the narrow space, and the movement transmitting body is formed by linking a plurality of rectangular link elements.
Each element is bent so that it can bend in one direction.
Links are connected to each other by pins,
A roller is installed at the bottom of the
A pipe decontamination apparatus characterized by being carried out . 2. In the primary piping of a nuclear power plant
Mechanical removal of oxides containing radioactive substances attached to the surface
In a pipe decontamination apparatus, a working unit main body for performing decontamination work, and the working unit main body
Attached to the moving transmitter that moves in the axial direction and the piping to be decontaminated
Before being installed outside the narrow space where
A moving force generator for applying a moving force to the moving transmission body.
And the work unit body installed outside the narrow space.
Work power generator for generating work power, and the work power generator
Work force transmitting the work power generated in
A power transmission unit, the work unit main body, the work power transmission unit, and the movement transmission.
The body is configured to be able to be inserted into the pipe from the narrow space, and the working power transmission body passes through the inside of the movement transmission body.
Transmitting the working power to the working unit main body.
That the pipe decontamination apparatus. 3. The working unit main body according to claim 1, wherein
Is a grinding wheel, a grinding wheel rotation actuator and a grinding wheel pressure contact
And a high-pressure water flowing toward the inner surface of the pipe.
A cleaning unit for spraying and a driving unit for rotating the polishing unit
An alignment unit for automatically aligning the working unit main body;
A pipe decontamination apparatus comprising: a connecting means for connecting to a dynamic transmission body .