Inner surface decontamination device for a tube

Abstract

To securely collect contaminants by efficiently decontaminating a tube body internal surface that radioactive substances stick on and so on.SOLUTION: A tube body internal surface decontamination device comprises: a laser light irradiation unit 11 which is inserted into a tube body 1 having both ends held by holders 17A, 17B, a tube body inner surface being irradiated with laser light L, guided into the tube body 1 through a condensing optical system 16, through a cone mirror 22; a direct-acting mechanism 31 which places the laser light irradiation unit 11 in linear motion axially in the tube body 1; and compressed air blowing means 25 which supplies compressed air into the tube body 1. The laser light irradiation unit 11 is placed in linear motion in the tube body 1, the tube body inner surface is irradiated with the laser light reflected in a circumferential ring shape at a circular cone vertex position of the corn mirror 22 to remove radioactive substances on the tube body inner surface, and the removed contaminants are discharged from the tube body 1 with an air flow formed in the tube body 1.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an inner surface decontamination device for a pipe, and more particularly to an inner surface decontamination device for removing radioactive substances from the inner surface of a small-diameter pipe or the like whose inner surface is contaminated with radioactive substances.

Background Art

[0002] In the decommissioning of nuclear power plants accompanying the measures for decommissioning and the demolition work of power plant facilities, a large amount of small-diameter pipes as radioactive waste in which radioactive substances adhere to the inner surface of the pipe or the surface metal of the inner surface of the pipe has radioactivity is generated. Various techniques have been developed and proposed to decontaminate the inner surface of these small-diameter pipes to the clearance level and reduce the amount of radioactive waste.

[0003] As an example, a dry decontamination device has been proposed in which a projectile (blast material) having an acute-angled shape is projected onto the inner surface of a pipe to decontaminate the inner surface of a small-diameter pipe (Non-Patent Document 1). This dry decontamination device is said to be able to decontaminate the inner surface of a pipe in a shorter time compared to a conventional blast device by projecting a large number of minute steel piece projectiles having an acute-angled shape onto the inner surface of the pipe.

[0004] Also, an electrolytic decontamination device has been proposed in which an electrolytic solution is sprayed onto the inner surface of a pipe to decontaminate the inner surface of a small-diameter pipe (Non-Patent Document 2). This electrolytic decontamination device can efficiently decontaminate the inner surface of a pipe by electrolytically polishing the inner surface of the pipe using an electrode that can move inside the pipe while spraying the electrolytic solution onto the inner surface of the pipe.

[0005] In the dry decontamination device disclosed in Non-Patent Document 1, there is a risk that radioactive waste remains due to the pushing-in of the projectile projected onto the inner surface of the pipe, resulting in a decrease in decontamination efficiency. Also, there is a problem that the used and recovered projectiles need to be treated as secondary waste. In the electrolytic decontamination device as well, there is a problem that a treatment process for the electrolytic solution recovered as secondary waste, treatment equipment, additional processes such as pipe cleaning and drying, and additional equipment are required.

[0006] Each of the above-mentioned devices requires processes and equipment for handling secondary waste such as projection materials and electrolytes. In contrast, there is a decontamination technology that does not generate such secondary waste and facilitates post-treatment processes by gasifying the removed substances (Patent Document 1).

[0007] This decontamination method involves irradiating the material to be decontaminated with laser light to remove the radioactive oxide layer on the material's surface. In this embodiment, a guide pipe forming the optical path of the laser beam is inserted into the piping material to be decontaminated. The laser beam is deflected at a right angle by a beam splitter and a reflective mirror installed inside the guide pipe and irradiated onto the inner surface of the piping material. At this time, the piping material is placed on a mobile trolley equipped with a rotating mechanism, and the piping material can be rotated around its axis by driving the rotating mechanism. [Prior art documents] [Non-patent literature]

[0008] [Non-Patent Document 1] Daisuke Tsuchida, et al., "Development of a method for internal decontamination of small-diameter pipe waste (Part 3)," [online], published August 20, 2018, Atomic Energy Society of Japan, [Accessed September 10, 2019], Internet.<URL:https: / / confit.atlas.jp / guide / event / aesj2018f / subject / 1F17 / advanced> [Non-Patent Document 2] Satoshi Maruyama, et al., "Development of an electric field decontamination device for piping," [online], published August 20, 2018, Atomic Energy Society of Japan, [accessed September 10, 2019], Internet.<URL:https: / / confit.atlas.jp / guide / event / aesj2018f / subject / 1F18 / advanced> [Patent Documents]

[0009] [Patent Document 1] Japanese Patent Application Publication No. 8-110396 [Overview of the Initiative] [Problems that the invention aims to solve]

[0010] According to an embodiment of the invention disclosed in Patent Document 1, the decontamination of the inner surface of a pipe material is performed by guiding laser light generated by the above-mentioned laser generator into the pipe material through a guide pipe and irradiating it so as to focus on a single point on the inner surface of the pipe material via a focusing lens (irradiation optical device). In order to decontaminate the entire inner surface of the pipe material, it is necessary to move the irradiation position by moving the pipe material by a predetermined amount in the axial direction of the pipe material while it is placed on a mobile trolley, and by rotating the pipe material by a predetermined amount around its axis using a rotation mechanism on the trolley.

[0011] At this time, the guide pipe is inserted and held from the open end of the piping material in line with the laser beam irradiation position, and the suction port of the material removal device is positioned as close as possible to the irradiation position. The material removed from the inner surface of the piping material is sucked up from this suction port and collected in the material removal device.

[0012] In the invention disclosed in Patent Document 1, the irradiation position of the laser beam on the piping material to be decontaminated is adjusted in accordance with the movement of the mobile trolley. Therefore, a certain degree of precision is required in controlling the amount of movement of the mobile trolley, and the drive system must also operate in accordance with the precision of the control. Furthermore, since the material removal recovery device also needs to be moved in accordance with the movement of the mobile trolley, there is a problem that the overall configuration of the device becomes large and complex. In addition, although the gasified material removal is recovered by the suction function of the material removal recovery device, it is not possible to completely suction the generated gas, so additional equipment is required to ensure that the generated gas is kept within the working environment.

[0013] The applicant has proposed a pipe internal decontamination device that solves the problems of the conventional technology described above (Japanese Patent Application No. 2020-161019) (hereinafter referred to as the proposed device). Figure 5 schematically shows a part of the proposed device 100 and the operation of the device during the decontamination of the pipe 1 to be decontaminated. An example of the pipe 1 to be decontaminated is assumed to be a small-diameter pipe contaminated with radioactive material, which is generated in large quantities in dismantled nuclear power plant facilities as described above, and the radioactive material etc. adhering to the inner surface (surface) of the pipe is scraped off by irradiation with laser light L.

[0014] In the proposed device 100, as a means of irradiating the inner surface of the tube 1, a axially movable laser beam irradiation probe 120 (hereinafter referred to as probe 120) is equipped with a reflective mirror 122 that deflects the irradiation direction of the laser beam L guided from a laser beam irradiation unit (not shown), and a mirror rotation mechanism 135 that imparts rotational movement to the reflective mirror 122.

[0015] The laser light L is guided into the probe 120 via an optical fiber 118 emitted from a known laser oscillator (not shown) as a light guide. As shown in Figure 5, the probe 120 houses a glass or metal reflective mirror 122 with a predetermined mirror surface and a mirror rotation mechanism 135 that rotates the reflective mirror 122 around the axis X. As shown in Figures 5 and 6, the reflective mirror 122 is eccentric by a distance e from the axis X of the probe 120 and is mounted on the tip of a mirror support shaft 121 that is provided parallel to the axis X, with its mirror surface at an angle of approximately 45° to the axis X. Therefore, the laser light L guided parallel to the axial direction of the probe 120 is reflected and deflected by approximately 90° by the reflective mirror 122 and irradiated toward the inner surface of the tube 1.

[0016] As shown in an enlarged view in Figure 6, the reflective mirror 122 is supported by the mirror support shaft 121. By rotating the mirror rotation mechanism 135 around the axis X using a built-in motor (not shown), the irradiation trajectory Lt of the laser beam L is made approximately circular, thereby irradiating the inner surface of the pipe body 1 (Figure 5) to be decontaminated in a circular manner. Furthermore, by moving the mirror rotation mechanism 135 linearly in the longitudinal direction of the pipe body 1, decontamination work can be performed on the entire longitudinal surface of the inner surface of the pipe body 1.

[0017] Incidentally, in the proposed device 100, in order to decontaminate the entire inner surface of the pipe by irradiating it with laser light L, it is necessary to have a mirror rotation mechanism 135 and a linear motion mechanism (not shown) for the probe 120, and to perform operational control to move the circumferential irradiation area of ​​the laser light L without gaps in the longitudinal direction of the pipe by rotating the reflective mirror 122. For this reason, the configuration of the probe 120 becomes complex, and it is necessary to operate the probe 120 while controlling the mutual operation of each drive mechanism by the control unit 132, etc. The number of pipes generated in decommissioning and dismantling work of power plants is enormous, so decontamination work will take a great deal of time.

[0018] Therefore, the object of the present invention is to solve the problems of the conventional technology described above and to provide a pipe internal decontamination device that can efficiently decontaminate the inner surface of pipes and the like and reliably recover the decontaminated material. [Means for solving the problem]

[0019] To achieve the above object, the apparatus for decontaminating the inner surface of a pipe according to the present invention has a deflection means for deflecting the laser light guided into the interior from a laser oscillator via a condensing optical system, and a laser light irradiation means which is formed of a cylindrical body inserted into the pipe for irradiating the inner surface of the pipe to be decontaminated, both ends of which are held by holding means, a linear motion drive mechanism for linearly moving the laser light irradiation means in the axial direction within the pipe, and a compressed air supply means for supplying compressed air into the pipe. By the operation of the drive means, the laser light irradiation means is linearly moved within the pipe, and the laser light deflected by the deflection means is irradiated onto the inner surface of the pipe to peel off the radioactive substances on the inner surface of the pipe, and the radioactive substances peeled off are discharged from the pipe as decontaminated substances by an air flow formed within the pipe by the compressed air supply means.

[0020] It is preferable that decontaminated substances in the air flow are collected by decontaminated substance collection means provided on the discharge side of the air flow.

[0021] It is preferable that the laser light irradiation means deflects the laser light guided along the axial center line direction inside the cylindrical body by the deflection means at a substantially right angle to the axial center line.

[0022] The deflection means is a cone mirror fixedly held at the tip position of the laser light irradiation means, and it is preferable that the laser light guided along the axial center line direction inside the cylindrical body is deflected in a circumferential ring shape at the cone apex position of the cone mirror.

[0023] It is preferable that the holding means holds both ends of the pipe while ensuring airtightness so that the axial center line of the pipe and the axial center line of the laser light irradiation means substantially coincide.

Brief Description of Drawings

[0024] [Figure 1] An apparatus configuration diagram showing a configuration of an embodiment of the apparatus for decontaminating the inner surface of a pipe according to the present invention in a partial cross-section and a block diagram. [Figure 2]Figure 1 is a partially enlarged cross-sectional view showing the configuration of one embodiment of the laser light irradiation probe for the pipe body internal decontamination device. [Figure 3] Figure 2 is a schematic diagram illustrating the configuration of the angle deflection mechanism for the laser light irradiation probe of the decontamination apparatus shown, and the irradiation state of the laser light. [Figure 4] Diagrams ((a) to (d)) illustrating the state of the decontamination work on the inner surface of a pipe using the pipe inner surface decontamination device of the present invention. [Figure 5] A partial cross-sectional view showing an example configuration of the proposed device as a conventional technology. [Figure 6] Figure 6 is a schematic diagram illustrating the operating state of the angle deflection means (reflecting mirror) of the proposed device. [Modes for carrying out the invention]

[0025] The configuration of one embodiment of the pipe body internal decontamination device of the present invention will be described below with reference to Figure 1.

[0026] Figure 1 is a diagram showing the overall configuration of the pipe internal decontamination device 10 of the present invention, which is set with a pipe 1 cut to a predetermined length to be decontaminated, similar to that shown in Figure 5. In this figure, equipment and means consisting of known configurations other than those whose form and operation are characteristic of the invention are shown as block diagrams. As an example of the pipe 1 to be decontaminated in the present invention, as in the case of Figure 5, it is assumed to be a small-diameter pipe (φ10~100mm) contaminated with radioactive material, which is generated in large quantities in dismantled nuclear power plant facilities. The substances removed from the inner surface (surface) of the pipe to be decontaminated by the pipe internal decontamination device 10 of the present invention include radioactive material attached to the surface of the pipe, and radioactive waste particles formed when the surface metal of the radioactive pipe 1 is scraped off and gasified by irradiation with laser light L, and then re-solidified into granular form. Various parts of radioactive waste recovered by the decontamination work using the device of the present invention are collectively referred to as "decontaminated material".

[0027] The pipe body internal decontamination device 10 consists of a laser beam irradiation unit 11 that holds one end of the pipe body 1 to be decontaminated, a decontaminated material recovery unit 12 that holds the other end of the pipe body 1, and a linear drive system 30 that moves the laser beam irradiation probe 20 (hereinafter referred to as probe 20) in the axial direction (longitudinal direction of the pipe body).

[0028] The laser light irradiation unit 11 consists of a laser oscillator 15, a laser light irradiation probe 20 (described later) that irradiates the inner surface of the tube with laser light L from the laser oscillator 15, and a focusing optical system 16 provided on the optical path that guides the laser light L to the laser light irradiation probe 20.

[0029] [Configuration of each part of the laser light irradiation unit] In this embodiment, the laser oscillator 15 consists of a known oscillator capable of emitting a continuous wave (CW) laser beam L with an output of approximately 300 W. The laser beam L is guided from the laser oscillator 15 to the rear end of the probe 20 via a focusing optical system 16 in the optical path. The laser beam L is collimated into parallel light by a group of lenses (not shown) in the focusing optical system 16 and focused into a narrow beam, and guided into the probe 20 using an optical fiber 18 wired inside the rear end probe 20 as a light guide.

[0030] As shown in Figures 1 and 2, the probe 20 consists of an elongated stainless steel cylinder with an outer diameter sufficiently smaller than the inner diameter of the pipe 1 to be decontaminated. Figure 2(a) shows a part of the basic configuration of an elongated cylindrical probe 20 as one embodiment. Figure 2(b) shows the state in which the laser light L guided through the optical fiber 18 within the probe 20 shown in Figure 2(a) is reflected by the cone mirror 22.

[0031] As shown in Figure 2(a), the probe 20 consists of a front probe 20A that houses a cone mirror 22 as a means of deflecting the optical path of the laser beam L, and a rear probe 20B that serves as a support tube to support the entire probe 20 and allow it to move in a straight line. As a means of deflecting the optical path of the laser beam L, a cone mirror 22 is housed, which has a conical shape with a cone apex angle of 90°. As shown in Figure 2, the cone mirror 22 is fixedly held on the inner surface of the tip side of the probe 20 by a base block 25 so that the apex of the cone coincides with the axis line X of the probe 20. The cone mirror 22 in this embodiment is an aluminum molded product, but various metal materials such as copper and stainless steel, or ultra-high heat resistant resin can also be used as materials. The molded cone surface is given a mirror finish by a metal film coating. The cone mirror has various names, such as conical mirror and cone mirror. In this embodiment, a right-circular cone with a vertex angle of 90° is assumed. However, in order to ensure accuracy and ease of assembly of the parts, it is also preferable to have a component in which a holding part such as a cylinder, like the base block 25, is integrally formed on the bottom surface of the right-circular cone.

[0032] The front end probe 20A is fitted with a cylindrical transparent glass component, which has the same outer diameter as the probe 20, around its entire circumference, instead of stainless steel. This glass component functions as an ejection window 23, which directs the laser light L reflected at the apex of the cone mirror 22 toward the surface of the tube 1, as will be described later.

[0033] The irradiation of the inner surface of the tube body 1 by the probe 20, which serves as a means of irradiating with laser light L in this configuration, will be explained with reference to Figures 1, 2(b), and 3. The laser light L generated by the laser oscillator 15 and guided into the probe 20 via the focusing optical system 16 travels along the axis X of the probe 20 using the optical fiber 18 as a light guide, and is irradiated from the end face of the optical fiber 18 towards the apex of the cone mirror 22 within the front end probe 20A. In this state, the laser light L is reflected by the mirror surface in the immediate vicinity of the apex of the cone mirror 22, which is cone-shaped. As shown in Figure 3, this reflection phenomenon is deflected at an angle approximately perpendicular to the incident direction of the laser light L, with the apex of the cone mirror 22 as the center of the circle, and is reflected radially in all directions (360° directions in a plane perpendicular to the axis X). Therefore, the reflected laser light Lr passes through the ejection window 23 of the probe 20 and is irradiated in a circumferential ring shape toward the inner surface of the tube 1 located on the outer circumference of the probe 20.

[0034] [Configuration of the decontamination material collection unit] As shown in Figures 1 and 3, the decontamination material recovery unit 12 consists of a compressed air supply means 25 that supplies compressed air into the pipe body 1 from an air nozzle 26 provided on a holder 17B at the rear end of the pipe body to discharge decontamination material d from inside the pipe body 1, which has been scraped off from the inner surface of the pipe body and the surface layer of the inner surface of the pipe body by irradiation with a circumferential ring-shaped laser beam L (hereinafter, the act of removing deposits from the inner surface of the pipe body by scraping off or scraping off the surface of the pipe body to a predetermined thickness by irradiation with a laser beam L), and a known decontamination material recovery means 27 that collects, recovers, and removes the decontamination material d discharged from inside the pipe body 1 by the compressed air supplied into the pipe body 1.

[0035] The compressed air supply means 25 has a known compressed air cylinder and a regulator (not shown) as a pressure source, and supplies compressed air at a predetermined pressure and volume to the pipe 1 during the decontamination work on the inner surface of the pipe by the probe 20, thereby forming an airflow f inside.

[0036] The decontamination material recovery means 27, provided on the discharge passage 29, is equipped with an exhaust filter 28 such as a HEPA filter or activated carbon filter inside. By operating a built-in blower (not shown), it draws in compressed air containing decontamination material d scraped off from the inner surface of the pipe, filters it through the internal exhaust filter 28 to collect the decontamination material d, and exhausts the clean air outside the device.

[0037] As a means of holding the pipe body 1, the holders 17A and 17B that hold both ends of the pipe body 1 are made of hard rubber cylinders in the shape of a frustoconical shape with a larger diameter on the side that holds the pipe body 1, and are supported on the frame 18. By applying an appropriate gripping force axially to both ends of the pipe body 1 with these holders 17A and 17B, the tip (decontaminated material collection side) and rear end (laser light irradiation side) of the pipe body 1 can be held in an airtight state while the axis of the pipe body 1 and the axis of the holders 17A and 17B are approximately aligned. If the diameter of the pipe to be decontaminated is determined, the shape of the holders 17A and 17B may be a cylindrical shape that can circumvent the pipe body while ensuring airtightness. Alternatively, a steel pipe or the like with an airtightness-retaining member such as a packing attached to the part that holds the pipe body may be used.

[0038] [Drivetrain Configuration] As shown in Figure 1, the drive system 30 consists of a linear motion mechanism 31 that moves the probe 20 longitudinally inside the pipe 1. The linear motion mechanism 31 has the function of moving the probe 20 along the linear guide 33 in response to an operation command from the control unit 32, for example as shown in Figure 1, so that the probe 20 moves linearly along its axis X inside the pipe 1 to be decontaminated. As the linear motion mechanism 31, a cylinder rod that can extend and retract along the linear guide 33, a belt drive mechanism, or a rack and pinion mechanism can be used.

[0039] A brief explanation will be given regarding the link between the linear motion of the probe 20 by the linear motion mechanism 31 and the irradiation of the circumferential ring-shaped laser beam L that is irradiated onto the inner surface of the tube via the cone mirror 22. As shown in Figure 3, the laser beam L is irradiated onto the mirror surface near the apex of the cone mirror 22 and reflected in a 360° direction. The reflected light passes through the emission window 23 of the probe 20 and is irradiated onto the inner surface of the tube 1 in a circumferential ring shape. At this time, the ability to remove attached substances, etc., from the tube surface differs depending on the irradiation intensity of the laser beam L on the inner surface of the tube. For this reason, the stopping time of the linear motion mechanism 31 during the irradiation stage is set according to the removal ability. When the attached substances and a predetermined thickness of the tube surface layer are removed in a circumferential ring shape, the linear motion mechanism 31 moves the probe 20 in a few steps to the untreated area adjacent to the removed area on the inner surface of the tube, and the removal work by irradiating the untreated area with laser beam L is continued. The step amount by which the probe 20 moves should be set according to the irradiation width of the laser beam L on the surface of the tube.

[0040] [Decontamination work on the inside of pipes] The procedure for performing decontamination work on the inner surface of pipes and the like using the pipe inner surface decontamination device 10 of the present invention will be explained with reference to the figures in Figure 4. Figure 4(a) shows the state in which both ends of the pipe body 1 to be decontaminated are held by holders 17A and 17B. The tip of the probe 20 is located at the holder 17B and is in close, slidable contact with the narrow end of the holder 17B while ensuring airtightness. The figure also shows the state in which, prior to scraping the inner surface of the pipe, compressed air is supplied into the pipe body 1 from the air nozzle 26 of the compressed air supply means 25, and an airflow f is formed inside the pipe body 1. In this state, the linear motion mechanism 31 (Figure 1) is operated to advance the probe 20 into the pipe body 1, and when the ejection window 23 of the probe 20 passes the end of the pipe body 1, the laser beam L is irradiated onto the inner surface of the pipe body (Figure 4(b)). Irradiation of the inner surface of the pipe body with the laser beam L is performed by the irradiation of the cone mirror 22 with the laser beam L which is controlled in advance, and the coordinated operation of the linear motion mechanism 31 of the probe 20, as described above. When the surface of the tube 1 is irradiated with laser light L in a circumferential ring shape, the thin layer of radioactive material attached to it is scraped off by the energy of the laser light, and at the same time it is gasified and re-solidified as fine particles in the air. Since a sufficient airflow f is formed inside the tube 1, the decontaminated material d as fine particles is sent towards the tip of the tube 1 by the airflow f, and is collected by the exhaust filter 28 of the decontaminated material recovery means 27 via the exhaust pipe 29, and the clean air is exhausted outside the device (Figure 4(c)). The decontamination work on the inner surface of the tube is performed along the entire length of the tube by advancing the probe 20 to the tip of the tube 1. Irradiation of the laser light L by the cone mirror 22 ends when the irradiation point reaches the tip of the tube 1 (Figure 4(d)). The timing of the start and end of the irradiation of the laser light L may be determined by equipping the probe 20 with a known position sensor, or by pre-recognizing the total length of the tube 1 to be decontaminated and setting that as the amount of movement of the probe 20.

[0041] The figures described above depict a configuration in which the inner surface of a horizontally installed pipe 1 is decontaminated. However, the pipe 1 may also be installed vertically, and the probe 20 may descend inside the pipe 1 to decontaminate the inner surface of the pipe. In this case, the decontaminated material d falls by its own weight and can also be forcibly and efficiently discharged by a downward airflow f.

[0042] It should be noted that the present invention is not limited to the embodiments described above, and various modifications are possible within the scope of each claim. In other words, embodiments obtained by combining technical means that have been appropriately modified within the scope of the claims are also included in the technical scope of the present invention. [Explanation of symbols]

[0043] 1. Body 10. Pipe body internal decontamination device 11. Laser beam irradiation unit 12 Decontamination Material Collection Unit 15. Laser Oscillator 16. Focusing Optical System 17A, 17B holder 20. Laser light irradiation probe (probe) 22 Corn Mirror 25 Compressed air supply means 26 Air Nozzles 27. Means of recovering decontaminated materials 28 Exhaust filter 30 Drivetrain 31 Linear motion mechanism d Decontaminated material f Airflow L laser light X-axis center line

Claims

1. a laser beam irradiation means having a deflection means for deflecting a laser beam guided from a laser oscillator to the inside through a focusing optical system, the laser beam irradiation means being a cylindrical body inserted into the tubular body, both ends of which are held by a holding means, to irradiate the inner surface of the tubular body to be decontaminated; a linear motion drive mechanism that linearly moves the laser light irradiation means in the axial direction within the tubular body; compressed air supply means for supplying compressed air into the tubular body; Equipped with A tubular inner surface decontamination device characterized in that the laser light irradiating means is moved linearly within the tubular body by the operating operation of the driving means, and the laser light deflected by the deflection means is irradiated onto the inner surface of the tubular body to scrape off radioactive material inside the tubular body, and the scraped off radioactive material is discharged from the tubular body as decontaminated material by an air flow formed inside the tubular body by the compressed air supply means.

2. 2. The apparatus for decontaminating the inner surface of a tubular body according to claim 1, wherein the material to be decontaminated in the air flow is collected by a material to be decontaminated recovery means provided on the discharge side of the air flow.

3. 2. The tubular body inner surface decontamination device according to claim 1, wherein the laser light irradiation means deflects the laser light guided inside the cylindrical body along its axial line direction at an angle approximately perpendicular to the axial line using the deflection means.

4. 2. The tubular body inner surface decontamination device according to claim 1, wherein the deflection means is a cone mirror fixed and held at a tip position of the laser light irradiation means, and the laser light guided inside the cylindrical body along its axial direction is deflected into a circumferential ring shape at the apex of the cone of the cone mirror.

5. 2. The tubular inner surface decontamination device according to claim 1, wherein the holding means is capable of holding both ends of the tubular body while ensuring airtightness so that the axial line of the tubular body and the axial line of the laser light irradiation means are approximately aligned.

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