JPH11316298A - Processing method and processing device of radioactive material containing component - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily and efficiently process such as disassembling and checking such components as valve placed in a fluid piping containing radioactive material in a reactor power station. SOLUTION: A component 2 to be processed is covered with a light transmitting shield 21, the inside of the shield 21 is depressurized, and the processing work of the component 2 is done from outside by using the glove part 22 provided to the shield 21. By this, as the size of the shield 21 is required large enough to cover the component, it can be constituted in a smaller device than a conventional clean house. Thus, the man-day and time necessary for placing and removal done at every processing work are small and spending matter is little needed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for treating a device containing a radioactive substance, and a treatment apparatus used for the method.

[0002]

2. Description of the Related Art In a facility handling radioactive materials such as a nuclear power plant, a large number of pipes containing radioactive materials are laid. Such pipes are provided with devices such as pumps and valves, and these devices need to be periodically disassembled, inspected, repaired, and the like. When processing equipment that contains such radioactive materials, the radioactive materials contained in them may be scattered around when the seals are released or disassembled, causing radioactive contamination around the work site. There is. Therefore, a method of working around a processing site in a clean house has conventionally been adopted.

FIG. 5 is an explanatory view showing a conventional method using such a clean house. A clean house 3 is installed so as to cover an area around a device 2 (in this example, a valve) provided in a pipe 1 containing a radioactive substance. The clean house 3 is at least large enough to allow the worker 4 to enter and work therein, and a sheet member 6 such as a vinyl sheet is provided on a support member 5 formed by assembling steel or the like.
Is formed. A seal portion 7 such as a seal tape is provided in a portion of the sheet material 6 through which the pipe 1 penetrates, and a pipe connection portion 10 for connecting a pipe 9 such as a hose communicating with the pressure reducing device 8 is provided in the sheet material 6. Can be Since the inside of the clean house 3 is a contaminated section 11 in which radioactive substances are suspended, the worker 4 carries out a processing operation by installing radiation protection equipment as shown in the figure. Note that the pressure reducing device 8 is provided for the purpose of keeping the pressure inside the clean house 3 at atmospheric pressure or lower so that dust containing radioactive substances and the like do not leak out of the contaminated section.

[0004]

However, such a conventional equipment processing method requires a processing apparatus having an internal space large enough to allow a worker to enter a clean house and work. The thing itself becomes big. For this reason, there are problems that a lot of man-hours and time are required for installation and removal of the clean house, which is required for each processing operation, and that many materials are used. Such an isolation operation by a clean house is a secondary operation in a nuclear power plant or the like, and it is not economically advantageous to use a large number of materials to set a wide range. In addition, it is necessary for the worker to carry out the processing work by wearing heavy radiation protection equipment such as a full-face mask in order to prevent internal exposure due to suction of radioactive substances floating in the contaminated compartment. In addition, it is necessary to perform decontamination work after the work in the place that has become a contaminated section, but decontamination work for a large section requires a long time, and it is not possible to freely enter the section until the work is completed. Therefore, an object of the present invention is to solve such a problem of the conventional device processing method.

[0005]

That is, the first aspect of the present invention is a method for treating a device containing a radioactive substance. The method is characterized in that a device to be processed is covered with a light-transmitting shield, the shield is depressurized, and the device is externally processed using a glove portion provided on the shield. It is. According to the above method, since the size of the shield only needs to cover the device, the device can be configured to be much smaller than a conventional clean house. Therefore, the man-hour and time required for installation and removal each time a processing operation is performed are small, and materials used are small. In addition, workers can perform processing work visually from outside the contaminated area through a light-permeable shield, and there is no danger of inhaling radioactive substances into the body, so there is no need to wear radiation protection equipment such as a full-face mask. . Furthermore, the decontamination work can be performed in a very short time because the contaminated section is extremely limited.

[0006] The invention according to claim 2 is an apparatus for processing a device containing a radioactive substance. And this device is
It is characterized by comprising a light-transmitting shield covering the device to be processed, a glove portion provided on the shield, and a pressure reducing device communicating with the shield. This processing apparatus is useful as an apparatus for performing the processing method described in claim 1. The invention according to claim 3 is an embodiment of the processing apparatus according to claim 2, wherein the shield is constituted by a support member and a light-transmissive sheet material supported by the support member. The material is provided with a glove portion and a pipe connection portion communicating with the pressure reducing device. With such a configuration, the device can have a simpler structure and can be configured at a low cost.

According to a fourth aspect of the present invention, there is provided a processing apparatus according to the second or third aspect, wherein the pressure reducing device includes a suction unit that sucks exhaust gas from the shield, and a suction device. And a detachable filter unit provided between the suction unit and the suction device for collecting particles containing a radioactive substance. With such a configuration, it is possible to effectively prevent the radioactive substance from being sucked into the suction device, and to facilitate replacement work of the filter unit and the like.

[0008]

Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view showing an example of a processing apparatus according to the present invention, and FIG. 2 is a view showing a state in which a processing operation of a device containing a radioactive substance is performed using the processing apparatus. In these figures, the processing apparatus 20 includes a light-transmitting shield 21 covering the equipment to be processed, a glove part 22 provided on the shield 21, and a decompression device 23 communicating with the shield 21.
It has. The shield 21 includes a support member 24 and a light-transmitting sheet material 25 supported by the support member 24. The sheet material 25 is provided with a glove part 22 and a pipe connection part 27 for connecting a pipe 26 such as a hose communicating with the pressure reducing device 23.

The support member 24 is formed by assembling column members and beam members such as steel and hard plastic. By bolting the column members and beam members together, quick assembly and disassembly can be achieved. By adding them, a shield 21 of an arbitrary size can be formed. Sheet material 2
5 is preferably a transparent or translucent soft plastic sheet such as a vinyl sheet or a polyethylene sheet. As the sheet material 25, a radiation shielding material usually used in this field, which is obtained by kneading a radiation shielding material such as lead powder so as not to transmit radiation, is used. The glove portion 22 is made of the same material as the sheet material 25, but need not be light-transmitting and may be opaque. In order to attach the glove portion 22 to the sheet material 25, a hole is formed in the sheet material 25, and an adhesive or a bonding tape 28 as shown in the drawing is used.
What is necessary is just to join. The pipe connection part 27 is made of a hard plastic cylinder. For example, when a hose is used as the pipe 26, the pipe connection part 27 has the same structure as a normal hose connection part.

To assemble the shield 21, first, as shown in FIG. 2, a support member 24 is assembled around the processing section of the apparatus 2, and the glove section 22 and the pipe connection section 2 are arranged therearound.
7 is put on the sheet material 25. When the sheet materials 25 are divided, they are joined to each other using an adhesive or a masking tape 29 as shown in FIG. Then, the inside of the shield 21 becomes the contamination section 30. A seal portion 31 such as a seal tape is provided in a portion of the sheet material 25 through which the pipe 1 penetrates.

Next, a method for treating a device containing a radioactive substance using the above-described apparatus will be described. First, a shield 21 is attached so as to cover the periphery of the equipment 2 to be processed as shown in FIG. At the time of attachment, a hole is formed in a portion of the sheet material 25 through which the pipe 1 penetrates, and a seal portion 31 is formed between the periphery of the hole and the pipe 1 to be sealed. Before installing the shield 21, necessary tools are arranged in necessary places of the device 2 in advance. Next, the pressure reducing device 23 is operated to operate the shield 21.
The pressure inside is reduced to about 100 to 200 torr. When the predetermined pressure reduction level is achieved, the operator puts his hand into the glove portion 22 and grasps the tool, and starts processing such as disassembly of the device 2. When the processing operation is completed, the operation of the pressure reducing device 23 is continued for a time when the radioactivity level in the contaminated section 30 falls sufficiently below the specified value, and then the shield 21 covering the periphery of the device 2 is removed. If trace levels of radioactivity remain, secondary decontamination is performed as necessary.

FIG. 3 shows one of the pressure reducing devices 23 constituting the present invention.
FIG. 4 is a longitudinal sectional view showing an example, and FIG. The decompression device 23 is a small exhaust device, and includes a suction unit 32 that suctions exhaust gas from the shield 21, a suction device 34, and a suction unit 32.
A detachable filter unit 33 for collecting particles containing a radioactive substance, provided between the filter unit and the suction device 34. The suction portion 32 has a top plate 35 having a suction port 32a to which the pipe 26 is connected, and a frame-shaped member disposed on the top plate 35 via a sealing body 36 made of an elastic body such as synthetic rubber such as natural rubber or butadiene rubber. Is provided. A pipe connecting portion 38 is provided on a side portion of the suction cylinder 37.

The filter section 33 includes an upper plate 39 having an opening 40, a lower plate 41 having an opening 42, a frame-like cylindrical body 43 disposed between the upper plate 39 and the lower plate 41, and an upper plate 39. And a secondary filter body 46 mounted on the inside of the cylindrical body 43. The upper plate 39, the lower plate 41, A plurality of through bolts 4 are provided around each of the top plate 35.
7 is concluded. Therefore, by fastening or releasing the through bolt 47, both the primary filter body 44 and the secondary filter body 46 of the filter section 33 can be attached and detached. Seal members 48 and 49 made of the same material as the seal member 36 are interposed between the cylinder 43 and the upper plate 39 and between the cylinder 43 and the lower plate 41, respectively.

The primary filter body 44 is a coarse filter capable of collecting radioactive particles of up to about 5 μm in gas. For example, a prefilter made of a polyester / polychlor fiber manufactured by Cambridge, USA can be used. The secondary filter body 46 is a fine filter that can collect up to about 97 to 99% of radioactive particles up to about 0.3 μm that cannot be captured by the primary filter body 44, for example, those made of glass fiber paper. Can be used. As such a filter, for example, HE sold by Cambridge, USA, which has a track record in this field, is used.
There is a PA filter and the like.

The suction device 34 includes a frame-shaped exhaust tube 50 connected to the lower side of the lower plate 41, a support plate 51 having an opening 52 provided inside the middle portion of the exhaust tube 50, and a support plate. 51 is provided with a suction blower 53 attached by a tubular attachment fitting 54. The suction side of the suction blower 53 is a suction chamber 55 formed by the mounting bracket 54, and a sealing body 56 is interposed between the peripheral edge of the mounting bracket 54 and the support plate 51 in order to maintain the airtightness of the suction chamber 55. Is done. Since the suction blower 53 applied to the present invention only needs to exhaust gas in a small space, a small blower having an electric motor output of about 250 W to 750 W, which is used in a small business vacuum cleaner or a home vacuum cleaner, is sufficient. is there.

A pipe connection portion 57 is provided at an upper portion of the exhaust pipe 50, and an exhaust port 58 is provided at a lower portion. The high-pressure side pipe 59 is connected to the pipe connection part 57, and the other end of the pipe 59 is connected to the differential pressure gauge 61 together with the low-pressure side pipe 60 from the pipe connection part 38. The differential pressure gauge 61 is provided for monitoring clogging of the primary filter body 44 and the secondary filter body 46 and the like. The decompression device 23 using the small suction blower as described above has a total weight of 10
Since it can be configured to be lightweight and compact of about Kg, it can be configured as a portable type that can be easily transported to the processing site.

Next, the operation of the pressure reducing device 23 will be described. By operating the suction blower 53, the exhaust of the shield 21 is sucked from the suction port 32a, passes through the opening 40, and the primary filter body 44 and the secondary filter While passing through the body 46 in order, dust containing radioactive material is collected. The clean gas from which dust has been removed is then sucked into the suction blower 53 from the suction chamber 55 and discharged from the exhaust port 58. The clogging of the primary filter body 44 and the secondary filter body 46 is monitored by the differential pressure gauge 61, and when the differential pressure level exceeds a predetermined level, the filter is replaced.

[0018]

As described above, according to the processing method of the first aspect, since the size of the shield is sufficient to cover the equipment, the apparatus can be configured to be much smaller than a conventional clean house. Therefore, the man-hour and time required for installation and removal each time a processing operation is performed are small, and materials used are small. In addition, the operator can perform the processing while viewing through the light-transmitting shield from outside the contaminated section, and there is no danger of sucking the radioactive substance into the body, so that there is no need to wear radiation protection equipment such as a full-face mask. Furthermore, the decontamination work can be performed in a short time because the contaminated section is extremely limited. Further, the processing apparatus according to the second aspect is useful as an apparatus for implementing the processing method according to the first aspect. Next, according to the processing apparatus of the third aspect, it is possible to make the apparatus simpler in structure and less expensive. Further, according to the processing device of the fourth aspect, it is possible to effectively prevent the radioactive substance from being sucked into the suction device, and to easily replace the filter unit.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an example of a processing apparatus of the present invention.

FIG. 2 is a diagram showing a state in which a processing operation of a device containing a radioactive substance is performed using the processing apparatus of FIG. 1;

FIG. 3 is a longitudinal sectional view showing one example of a decompression device 23 constituting the present invention.

FIG. 4 is a plan view of the pressure reducing device 23 of FIG.

FIG. 5 is an explanatory view showing a conventional method of performing a processing operation using a clean house.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Piping 2 Equipment 3 Clean house 4 Worker 5 Support member 6 Sheet material 7 Seal part 8 Decompression device 9 Pipe 10 Pipe connection part 11 Contamination section 20 Processing device 21 Shield 22 Glove part 23 Decompression device 24 Support member 25 Sheet material 26 Piping 27 Piping connection part 28 Laminating tape 29 Masking tape 30 Contamination section 31 Seal part 32 Suction part 32a Suction port 33 Filter part 34 Suction device 35 Top plate 36 Seal body 37 Suction cylinder 38 Pipe connection part 39 Upper plate 40 Opening 41 Lower Plate 42 Opening 43 Cylindrical body 44 Primary filter body 45 Holder 46 Secondary filter body 47 Through bolt 48 Seal body 49 Seal body 50 Exhaust cylinder 51 Support plate 52 Opening 53 Suction blower 54 Mounting bracket 55 Suction chamber 56 Seal body 57 Piping connection part 58 Exhaust port 59 Piping 60 piping 61 differential pressure gauge

Claims (4)

[Claims] 1. A method for treating a device containing a radioactive substance, comprising the steps of:
And processing the device 2 from the outside using a glove part 22 provided on the shield 21 by covering the inside of the shield 21 with a reduced pressure. 2. An apparatus for processing a device containing a radioactive substance, comprising: a light-transmitting shield 21 covering the device 2 to be processed; a glove portion 22 provided on the shield 21; A processing device for a radioactive substance-encapsulating device, comprising: a decompression device 23 communicating with the device. 3. The shielding body 21 includes a support member 24 and a light-transmitting sheet material 25 supported by the support member 24. The sheet material 25 includes a glove portion 22 and a decompression device 23.
The processing apparatus for a radioactive substance-encapsulated apparatus according to claim 2, further comprising a pipe connection part (27) communicating with the equipment. 4. A decompression device (23) collects particles including a radioactive substance provided between the suction portion (32) and the suction device (34), a suction device (34), and a suction device (34) for sucking exhaust gas from the shield (21). The processing apparatus for a radioactive substance-encapsulated apparatus according to claim 2, further comprising a removable filter section 33 that performs the operation.