JP3151667B2 - Laser decontamination system applied to contaminated inorganic surface - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface of an inorganic material such as concrete contaminated by a radioactive material containing radionuclides such as plutonium in a nuclear-related facility such as a nuclear power plant and a nuclear power plant, and a radioactive material handling facility such as a hospital. Is used to reduce the level of radioactive contamination by removing and recovering, that is, decontaminating. It is also used to decontaminate not only radioactive substances but also other harmful substances.

[0002]

2. Description of the Related Art In a nuclear facility or the like, a method of treating a concrete surface layer which is contaminated by radioactive substances by infiltration is performed by a worker wearing protective clothing and decontaminating by mechanical polishing / grinding of a breaker, a scabber, a planer, and the like. The method is representative.

However, these methods have the following problems. The high-speed rotation of the cutting edge causes the contaminated concrete to be scattered as fine powder, thereby contaminating workers (internal and external exposures) or secondary contamination of the periphery. It is difficult to apply to the upper surface such as the ceiling or the corner where the floor and the wall intersect. It is difficult to control the decontamination depth according to the contamination penetration depth. The cutting edge is contaminated. There is noise and vibration. The remote control required in a polluted environment is difficult.

[0004]

SUMMARY OF THE INVENTION According to the present invention, a laser irradiation head is moved to an arbitrary position by remote control to irradiate a laser beam so that a worker can enter a decontamination target area or a room at a frequency and time. It is intended to provide a decontamination system which can solve the conventional problems by reducing the amount of secondary products and recovering secondary products following the movement of the laser irradiation head.

[0005]

SUMMARY OF THE INVENTION The present invention provides a laser irradiation head for irradiating a contaminated inorganic material surface layer with light energy, a glass fiber for transmitting light energy to the laser irradiation head, and a method for transmitting light energy to the glass fiber. A laser oscillation device, a secondary product collection hood attached to the laser irradiation head, a secondary product collection hose having one end connected to the secondary product collection hood, and a second product collection hose connected to the other end of the secondary product collection hose. A connected secondary product recovery device;
A driving mechanism for driving the laser irradiation head, a moving device for moving the driving mechanism in the vertical and horizontal directions, a laser oscillation device, a secondary product recovery device, a control device for controlling the driving device and the moving device, The laser oscillation device, the secondary product recovery device, and the control device are arranged in a place isolated from the decontamination target area, and the control device controls the moving device and the driving mechanism to control the laser irradiation head and the secondary product recovery hood. Is moved vertically and horizontally to irradiate the inorganic material surface layer with light energy while changing the decontamination target position within the decontamination target area, and melt the inorganic material surface layer without scattering the contaminated fine powder around. And solidified by natural cooling to vitrify
The solidified glass layer is cooled by volume shrinkage.
This is a laser decontamination system applied to a contaminated inorganic substance surface layer, characterized in that the adhesive force is reduced, the adhesive is peeled off, and collected by a secondary product recovery hood.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the laser decontamination system of the present invention will be described with reference to the drawings.

<B> Laser decontamination system The decontamination system for the surface layer of inorganic substances such as contaminated concrete is irradiated with light energy such as CO ₂ laser or YAG laser while scanning the surface of the inorganic substance to melt the surface layer . Then, solidification (vitrification) is performed by natural cooling while containing the contaminants. The solidified glass layer has a reduced volume adhesiveness at the interface with the substrate due to volume shrinkage due to cooling, so that it can be easily peeled off with a brush or suction, and the subsequent collection can be easily performed by suction or the like. When fumes are generated by scanning irradiation of light energy, it is also possible to perform suction and discharge or suction and recovery with a local hood.

The following advantages are obtained by the above system. Since contaminants are trapped in the hood and collected by suction, workers can be prevented from being exposed to radiation and secondary pollution from surrounding areas. Since irradiation peeling is performed in a non-contact manner at a distance of 10 cm or more from a contaminated surface, it can be applied to a corner. By adjusting the irradiation conditions, the peeling depth can be controlled. The laser irradiation head is not contaminated because it is not in contact with the contaminated surface. Since the laser irradiation head is not in contact with the contaminated surface, it can be separated without noise and without vibration. Since light energy from a laser oscillation device installed in a distant place can be transmitted to a laser irradiation head by a flexible fiber or a mirror, remote control is possible.

<B> Operation of the laser decontamination system The drive mechanism capable of remote operation can hold the laser irradiation head and move the laser irradiation head to an arbitrary position three-dimensionally with respect to the space around the drive mechanism. it can. Here, the drive mechanism is mounted on a moving device that can be moved by remote control, the movement of the drive mechanism and the movement of the moving device are combined, and the laser irradiation head is moved to an arbitrary processing position by remote control,
By performing the laser irradiation while collecting the secondary products, the frequency and time of the workers entering the decontamination target area or the room for setting the processing environment can be reduced.

[0010] Further, secondary products generated by vitrification by a laser are prevented from being scattered by a secondary product recovery hood, and are recovered to a secondary product recovery device through a secondary product recovery hose. At this time, the hopper filter and the waste can of the secondary product recovery device can be replaced by a bag-out method.

[0011] Further, a plurality of laser irradiation heads are branched from one laser oscillation device, and the laser irradiation heads are irradiated simultaneously next to each other or irradiated on different portions, whereby the irradiation area per time can be increased.

An embodiment of the present invention will be described below with reference to the drawings.

<A> Configuration of Laser Decontamination System FIG. 1 is a diagram showing the configuration of a laser delamination apparatus, and FIG. 2 is a bird's-eye view of the entire laser delamination apparatus in a decontamination area or room. The glass fiber a transmits light energy oscillated from the laser oscillation device 3 to the laser irradiation head 2. The secondary products that have been prevented from being scattered by the secondary product recovery hood 1 are recovered through a secondary product recovery hose b into a secondary product recovery device 6 having a waste can and a hopper filter. The drive mechanism 4 holds the laser irradiation head 2 and moves the laser irradiation head 2 freely by remote control by the control device 7. In FIG. 1, the drive mechanism 4 is an articulated robot.
The moving device 5 has the driving mechanism 4 mounted thereon and is moved by a remote control from the control device 7. The laser irradiation head 2 can be moved to an arbitrary processing position by the movement of the driving mechanism 4 and the moving device 5. In FIG. 1, the moving device 5 is an electric bogie. S1, S2, S3, and S4 are control lines. Also, X
Is a machined surface. In FIG. 1, X is a wall, but a floor, a wall,
It is possible to have ceilings, and their intersections.

<B> Test of laser decontamination system Normal concrete, heavy concrete, and mortar are selected as simulated contaminant inorganic substances, and a CO ₂ laser and a YAG laser are irradiated under a combination of irradiation conditions shown in Table 1 below. Good vitrification peeling was possible.

[0015]

[Table 1]

<C> In the case of vitrification exfoliation After the formed glass layer is exfoliated, the same site is re-irradiated to enable vitrification exfoliation again, and by repeating this process, it can be applied to the decontamination of deeper penetration contamination. . When a substance lowering the melting point of concrete, for example, an aqueous solution of sodium chloride (concentration: 26%) is applied to a surface contaminated with concrete before irradiation, the amount of vitrification peeling is 10% as compared with the same irradiation conditions.
Increase to the extent. The generated glass layer can be more easily peeled off by increasing the standing time. In particular, it becomes easier after standing for about 4 weeks after irradiation. In addition, even if it is left for 4 weeks or more, the easiness of peeling is not further improved.

[0017]

According to the present invention, the following effects can be obtained. <B> The surface layer of the inorganic substance contaminated by the penetration of the radioactive substance can be decontaminated by vitrification using a laser. <B> By remotely operating a decontamination device disposed in a decontamination target area or a room, it is possible to provide a decontamination device that reduces the amount of exposure of workers and maintains a good sanitary environment during work. <C> A decontamination apparatus capable of collecting secondary products generated by vitrification using a laser without scattering, thereby reducing the exposure of workers and maintaining a good sanitary environment during operation. it can. <D> The secondary product can be recovered even if the re-laser irradiation position is moved to an arbitrary position by remote control. <E> By combining the movement of the drive mechanism and the movement of the moving device, a wider range of area can be machined with a single machining environment setting. <F> The amount of radioactive waste material can be reduced by decontaminating the contaminated concrete surface layer and isolating it from healthy concrete and using only the decontaminated contaminated concrete as radioactive waste material.

[Brief description of the drawings]

FIG. 1 is a device configuration of a laser peeling apparatus according to an embodiment of the present invention.

FIG. 2 is a bird's-eye view of the entire laser peeling apparatus in a decontamination target area or a room according to an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Secondary product collection hood 2 ... Laser irradiation head 3 ... Laser oscillation device 4 ... Drive mechanism 5 ... Moving device 6 ... Secondary product collection device 7 ... Control device a: Glass fiber b: Secondary product recovery hose S1, S2, S3, S4: Control line X: Processing surface

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Eito Akimichi 2-4 Shirane, Shirakata, Tokai-mura, Naka-gun, Ibaraki Pref. Japan Atomic Energy Research Institute (72) Inventor Hirofumi Kamada 1-25-chome Nishishinjuku, Shinjuku-ku, Tokyo No. 1 Taisei Construction Co., Ltd. (72) Inventor Wignaraja Shibakumaran 1-25-1, Nishi-Shinjuku, Shinjuku-ku, Tokyo Taisei Construction Co., Ltd. (72) Inventor Shunji Sato Hyogo-ku, Kobe City, Hyogo Prefecture 1-2 1-2, Tazakicho Mitsubishi Electric Corporation (72) Inventor Tatsuya Koga 1-2-1, Wadasakicho, Hyogo-ku, Kobe City, Hyogo Prefecture Inside Mitsubishi Electric Corporation (72) Inventor Tomoyuki Yamamoto Yokohama, Kanagawa Prefecture 2-2-1 Minatomirai, Nishi-ku, Shinsaibashi, Japan (72) Inventor Tetsuya Fujita 2-Chome, Minatomirai, Nishi-ku, Yokohama, Kanagawa No. Shinryo Corporation (56) References JP-A-9-281296 (JP, A) JP-A-7-209491 (JP, A) JP-A-7-225300 (JP, A) JP-A-4 JP-A-168400 (JP, A) JP-A-4-109200 (JP, A) JP-A-4-99999 (JP, A) JP-A-8-110396 (JP, A) JP-A-63-241399 (JP, A) Special Table 6-507977 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G21F 9/28 G21F 9/30

Claims (1)

(57) [Claims] 1. A laser irradiation head for irradiating light energy to a contaminated inorganic substance surface layer, a glass fiber for transmitting light energy to the laser irradiation head, a laser oscillation device for transmitting light energy to the glass fiber, and a laser irradiation head. A secondary product recovery hood attached to the secondary product recovery hood, a secondary product recovery hose connected at one end to the secondary product recovery hood, and a secondary product recovery connected at the other end of the secondary product recovery hose Device, a driving mechanism for driving the laser irradiation head, a moving device for moving the driving mechanism in the vertical and horizontal directions, and a control device for controlling the laser oscillation device, the secondary product recovery device, the driving device, and the moving device. A laser oscillation device, a secondary product recovery device, and a control device,
The control unit controls the moving device and the drive mechanism to move the laser irradiation head and the secondary product recovery hood vertically and horizontally in the area separated from the decontamination target area, Fine powder contaminated by irradiating light energy to the surface of inorganic material while changing the decontamination target position
The inorganic material surface layer melts without scattering the body around the own
Solidified by virtue of cooling, vitrified and solidified
The adhesion of the glass layer decreases due to volume shrinkage by cooling,
A laser decontamination system applied to a contaminated inorganic substance surface layer, wherein the laser decontamination system is separated and collected by a secondary product collection hood.