Decontamination system

Abstract

To efficiently remove contaminants from the target object. [Solution] The decontamination system comprises a shape measuring unit capable of measuring the position and shape of an object to be decontaminated, a dose distribution information acquisition unit that acquires information on the distribution of radiation doses in the object, a radiation source removal unit that removes radiation sources from the object, a movement mechanism that moves the radiation source removal unit relative to the object, and a control device that, based on the shape of the object measured by the shape measuring unit and the distribution information acquired by the dose distribution information acquisition unit, moves the radiation source removal unit using the movement mechanism and removes radiation sources from the portion of the object that has a radiation dose above a preset standard.

Description

[Technical Field]

[0001] The present disclosure relates to a decontamination system. [Background Art]

[0002] Patent Document 1 discloses a configuration that measures the radiation dose of a contaminated object, recognizes the shape of the contaminated object, and performs dry blast processing according to the recognized shape to remove radioactive contaminants adhering to the surface of the contaminated object. [Prior Art Literature] [Patent Literature]

[0003] [Patent Document 1] Japanese Unexamined Patent Publication No. Hei 3-81699 [Summary of the Invention] [Problem to be Solved by the Invention]

[0004] By the way, when decomposing a nuclear power plant, a large amount of waste is generated, such as reactor vessels, in-core structures inside reactor vessels, and piping. It is desired to efficiently perform decontamination work to remove radiation sources from these large amounts of waste objects.

[0005] The present disclosure has been made to solve the above problem, and an object thereof is to provide a decontamination system capable of efficiently performing decontamination work for removing radiation sources from an object. [Means for Solving the Problem]

[0006] To solve the above problems, the decontamination system according to this disclosure comprises a shape measurement unit, a dose distribution information acquisition unit, a radiation source removal unit, a moving mechanism, and a control device. The shape measurement unit is capable of measuring the position and shape of an object to be decontaminated. The dose distribution information acquisition unit acquires information on the distribution of radiation doses in the object. The radiation source removal unit removes radiation sources from the object. The moving mechanism moves the radiation source removal unit relative to the object. Based on the shape of the object measured by the shape measurement unit and the distribution information acquired by the dose distribution information acquisition unit, the control device moves the radiation source removal unit using the moving mechanism and removes radiation sources from the portion of the object that has a radiation dose above a preset standard. [Effects of the Invention]

[0007] The decontamination system described herein allows for the efficient removal of contaminants from target objects. [Brief explanation of the drawing]

[0008] [Figure 1] This is a side view showing the decontamination system according to the embodiment of this disclosure, in which the shape measurement unit and the dose distribution information acquisition unit are being used. [Figure 2] This is a plan view of a decontamination system according to an embodiment of the present disclosure. [Figure 3] This is a side view showing the decontamination system according to the embodiment of this disclosure, in which the radiation source removal unit is being used. [Figure 4] This is a block diagram showing the functional configuration of a decontamination system according to an embodiment of the present disclosure. [Modes for carrying out the invention]

[0009] The decontamination system according to the embodiment of this disclosure will be described below with reference to Figures 1 to 4. (Overall configuration of the decontamination system) As shown in Figures 1 to 4, the decontamination system 1 of this embodiment is used to remove radioactive materials and other radiation sources from an object W that has been contaminated by the attachment of radioactive materials, etc. Examples of the object W include waste generated when dismantling a nuclear reactor (not shown). Examples of nuclear reactors include a pressurized water reactor (PWR) which uses light water as a reactor coolant and neutron moderator to create high-temperature, high-pressure water that does not boil throughout the entire core, sends this high-temperature, high-pressure water to a steam generator to generate steam through heat exchange, and sends this steam to a turbine generator to generate electricity.

[0010] Object W includes, for example, the reactor vessel, internal structures, piping connected to the reactor vessel, and various components attached to them, all located within the reactor building (not shown). Object W is generated within the reactor building by dismantling these reactor vessel, internal structures, piping, and components. In other words, Object W is radioactive waste with various shapes, sizes, and materials. Furthermore, Object W may have different radiation levels depending on the part; for example, one side may have a high radiation level, while the other side may have a lower radiation level.

[0011] As shown in Figure 1, the decontamination system 1 is installed, for example, inside the reactor building or in a decontamination building 2 located outside the reactor building. The decontamination building 2 may be newly constructed for the installation of the decontamination system 1. A so-called greenhouse may be used as the decontamination building 2. Alternatively, an existing building may be repurposed as the decontamination building 2. The decontamination building 2 is installed to suppress the scattering of removed material into the surrounding area when the radiation source is removed from the target object W.

[0012] The decontamination building 2 has at least a floor 2f on which the decontamination system 1 is installed, walls 2w rising above from the floor 2f and surrounding the decontamination system 1, and a roof 2t that seals the space enclosed by the walls 2w from above. The object W to be decontaminated is brought into the decontamination building 2. The object W is placed on the floor 2f. The object W may also be placed on a base 3 provided on the floor 2f.

[0013] As shown in Figures 1 to 4, the decontamination system 1 comprises a shape measurement unit 10, a dose distribution information acquisition unit 20, a radiation source removal unit 30, a moving mechanism 40, an object holding unit 50, a recovery unit 60, and a control device 70 (see Figure 4).

[0014] As shown in Figures 1 to 3, the moving mechanism 40 moves the shape measurement unit 10, the dose distribution information acquisition unit 20, and the radiation source removal unit 30 relative to the object W. The moving mechanism 40 includes, for example, a pair of rails 41, a pair of support columns 42, a lifting beam 43, and a mounting platform 44.

[0015] A pair of rails 41 are installed on the floor 2f at intervals in the first horizontal direction D1. Each of the rails 41 extends parallel to each other along the surface of the floor 2f in the second horizontal direction D2, which intersects the first horizontal direction D1.

[0016] A pair of support columns 42 are mounted on a pair of rails 41. Each support column 42 extends upward from the rails 41 along the vertical direction Dv. Each support column 42 is mounted to be movable along the rails 41 in the direction of extension of the rails 41 (second horizontal direction D2) by a drive mechanism (not shown).

[0017] The lifting beam 43 extends in a first horizontal direction D1 and is horizontally spanned between a pair of rails 41. The lifting beam 43 is installed between a pair of support columns 42 so as to be able to move up and down in the vertical direction Dv by a drive mechanism (not shown).

[0018] The mounting table 44 is provided on the lifting beam 43. The mounting table 44 may be provided on the lifting beam 43 so as to be capable of advancing and retracting in the second horizontal direction D2 by a drive mechanism (not shown). The mounting table 44 can mount the shape measuring unit 10, the dose distribution information acquiring unit 20, and the radiation source removing unit 30, respectively. The shape measuring unit 10, the dose distribution information acquiring unit 20, and the radiation source removing unit 30 may be detachable from the mounting table 44 and replaceably attached to the mounting table 44. Further, the shape measuring unit 10, the dose distribution information acquiring unit 20, and the radiation source removing unit 30 may be arranged side by side on the mounting table 44, for example.

[0019] A plurality of sets of the moving mechanism 40 described above may be provided. In the case where a plurality of sets of moving mechanisms 40 are provided, for example, the moving mechanism 40 for measurement in which the shape measuring unit 10 and the dose distribution information acquiring unit 20 are provided on the mounting table 44, and the radiation source removing unit 30 is provided on the mounting table 44. and a decontamination moving mechanism 40 may be provided. The moving mechanism 40 is not limited to the configuration described above, and may be any other appropriate configuration such as one using a robot arm.

[0020] As shown in FIG. 1, the shape measuring unit 10 measures the position and shape of the object W. The shape measuring unit 10 measures the relative position of the object W with respect to the shape measuring unit 10 and the shape of the object W. The shape measuring unit 10 is, for example, a three-dimensional scanning device. The shape measuring unit 10 includes, for example, a camera. The shape measuring unit 10 may be configured to photograph the object W while moving its relative position with respect to the object W by the moving mechanism 40. The shape measuring unit 10 performs appropriate image processing based on an image captured by a camera, thereby three-dimensionally scanning the object W in the image, and measures the distance to each part of the object W and the shape of the object W.

[0021] A dose distribution information acquiring unit 20 measures the radiation dose of an object W. For the dose distribution information acquiring unit 20, for example, a gamma camera or a Compton camera is used. The dose distribution information acquiring unit 20 acquires distribution information of the radiation dose of the object W. The dose distribution information acquiring unit 20 may measure the radiation dose of each part of the object W while changing its relative position with respect to the object W by a moving mechanism 40. The dose distribution information acquiring unit 20 may acquire distribution information of the radiation dose by classifying the radiation dose of each part on the surface of the object W into a plurality of preset levels based on an image captured by a gamma camera.

[0022] As shown in FIG. 4, a radiation source removing unit 30 removes a radiation source from the object W. The radiation source removing unit 30 removes the radiation source from the object W while changing its relative position with respect to the object W by the moving mechanism 40. The radiation source removing unit 30 may scrape off the radiation source from the object W by gouging processing using a laser. The radiation source removing unit 30 may cut off the radiation source from the object W using a milling tool or a wall saw. The radiation source removing unit 30 may perform blasting processing in which granular materials such as sand, alumina, and glass beads are injected onto the object W, or water jet processing in which a liquid such as water is injected onto the object W, to scrape off the radiation source from the object W. The radiation source removing unit 30 may remove the radiation source from the object W by irradiating the object W with a laser. As the radiation source removing unit 30, any method other than those exemplified herein may be used as long as the radiation source can be removed from the object W.

[0023] As shown in FIG. 1 and FIG. 2, an object holding unit 50 holds (fixes) the object W on a base 3. The object holding unit 50 includes, for example, a holding member 51 and a holding member moving mechanism 52. The holding member 51 is, for example, a gripping claw capable of holding the object W. Multiple sets of the holding member 51 are provided on the base 3, for example, at intervals in the first horizontal direction D1. The holding member 51 is also provided on the movable rail 53 provided on the base 3, at intervals in the second horizontal direction D2. The holding member 51 is positioned on both sides of the object W placed on the base 3 in the second horizontal direction D2, and can hold the object W on the base 3 by gripping it from both sides.

[0024] The holding members 51 may be used separately for different purposes, such as one for holding a high-dose object W whose radiation dose is above a predetermined standard, and another for holding a low-dose object W whose radiation dose is below the standard. Multiple sets of holding members 51 may be provided depending on the shape of the object W.

[0025] The holding member moving mechanism 52 moves the holding member 51 relative to the radiation source removal unit 30. Each holding member moving mechanism 52 is provided so as to be movable along the moving rail 53 in a second horizontal direction D2. The holding member 51 is, for example, detachable from the holding member moving mechanism 52. The holding member moving mechanism 52 may be, for example, a robot arm.

[0026] As shown in Figure 3, the recovery unit 60 recovers the removed material from the object W by the radiation source removal unit 30. The recovery unit 60 may include, for example, a suction duct 61 positioned above the object W. The recovery unit 60 may also include a recovery unit movement mechanism, not shown, such as a robotic arm, which allows the suction duct 61 to move relative to the object W.

[0027] Furthermore, protective material 8 may be provided along the wall 2w of the decontamination building 2. The protective material 8 is installed for the purpose of protecting the decontamination building 2 and the wall 2w.

[0028] As shown in Figure 4, the control device 70 controls the operation of each part of the decontamination system 1. The control device 70 is a computer equipped with a CPU (Central Processing Unit), ROM (Read Only Memory), RAM (Random Access Memory), HDD (Hard Disk Drive) and other storage and signal receiving modules.

[0029] The CPU of the control device 70 executes a program that is pre-stored in the device, thereby realizing the functional configurations of the information acquisition unit 71, the program generation unit 72, and the operation control unit 73.

[0030] The information acquisition unit 71 acquires the position and shape of the object W measured by the shape measurement unit 10, and the radiation dose distribution information of the object W acquired by the dose distribution information acquisition unit 20.

[0031] The program generation unit 72 generates an operation program for operating the radiation source removal unit 30 based on the position and shape of the target object W and the radiation dose distribution information of the target object W, which are acquired by the information acquisition unit 71. Based on the position and shape of the target object W, the program generation unit 72 generates an operation program to move the radiation source removal unit 30 relative to the target object W using the movement mechanism 40, while maintaining an appropriate distance and orientation relative to the outer surface of the target object W for removing radiation sources with the radiation source removal unit 30. While moving the radiation source removal unit 30 with the movement mechanism 40, the program generation unit 72 generates an operation program to remove radiation sources from parts of the target object W where the radiation dose exceeds a preset standard.

[0032] The motion control unit 73 controls the operation of the radiation source removal unit 30 and the moving mechanism 40 based on the operation program generated by the program generation unit 72. Based on the generated operation program, the motion control unit 73 moves the radiation source removal unit 30 using the moving mechanism 40, and removes the radiation source from the portion of the target object W that has a radiation dose above a preset standard.

[0033] The operation control unit 73 further controls the recovery unit 60 to recover the removed material that is removed from the target object W by the radiation source removal process in the radiation source removal unit 30. The recovery of the removed material by the recovery unit 60 may be performed in parallel with the radiation source removal process in the radiation source removal unit 30, or it may be performed after the radiation source removal process.

[0034] In the decontamination system 1 described above, first, the object W is transported onto the base 3 by an object transport device (not shown). Subsequently, under the control of the control device 70, the shape measurement unit 10 and the dose distribution information acquisition unit 20 are moved relative to the object W by the moving mechanism 40, while acquiring information on the position, shape, and radiation dose distribution of the object W.

[0035] Next, the control device 70 generates an operation program to operate the radiation source removal unit 30.

[0036] Subsequently, the control device 70, based on the generated operation program, moves the radiation source removal unit 30 relative to the object W using the moving mechanism 40, and removes the radiation source from the portion of the object W that has a radiation dose above a preset standard.

[0037] After removing the radiation source from the object W, the control device 70 may use the dose distribution information acquisition unit 20 to reacquire information on the radiation dose distribution of the object W after the radiation source removal process. In this case, the removal of the radiation source is terminated when the radiation level in the entire object W after the removal process falls below the standard.

[0038] On the other hand, if any part of the object W after the removal process still has a radiation dose above the standard, the control device 70 has the radiation source removal unit 30 remove the radiation source again from the part of the object W that has a radiation dose above the standard. The control device 70 sequentially repeats the acquisition of radiation dose distribution information and the removal of radiation sources until the radiation dose in the entire object W after the removal process falls below the standard.

[0039] (Effects and Benefits) In the decontamination system 1 of the above embodiment, based on the shape of the target object W measured by the shape measurement unit 10 and the distribution information acquired by the dose distribution information acquisition unit 20, the radiation source removal unit 30 is moved by the movement mechanism 40, and the radiation source is removed by the radiation source removal unit 30 from the portion of the target object W that has a radiation dose above a preset standard. In this way, by moving the radiation source removal unit 30 according to the shape of the object W and removing the radiation source from the object W, the radiation source can be removed without the worker having to approach the radiation source. Furthermore, the position of the radiation source removal unit 30 relative to the object W can be set to a state suitable for radiation source removal, allowing for efficient removal of the radiation source. By removing the radiation source from the portion of the object W that has a radiation level above a predetermined standard, it is not necessary to remove the radiation source from the portion with a radiation level below the standard, thus also allowing for efficient removal of the radiation source. As a result, the removal of contaminants from the object W can be carried out efficiently.

[0040] Furthermore, in the above embodiment, since a holding member 51 capable of holding the object W is provided, the radiation source can be efficiently removed while the object W is held by the holding member 51.

[0041] Furthermore, in the above embodiment, the holding member 51 is detachable from the holding member moving mechanism 52. This allows the holding member 51 to be replaced according to the radiation dose of the object W, thereby suppressing contamination of the holding member 51 by the object W with a high radiation dose.

[0042] Furthermore, in the above embodiment, the removal material removed from the target object W can be recovered by the recovery unit 60. Therefore, it is possible to suppress the increase in radiation levels at the site where the radiation source is removed due to the removal material.

[0043] (Other embodiments) Although embodiments of this disclosure have been described in detail above with reference to the drawings, the specific configuration is not limited to these embodiments and may include design changes and the like that do not depart from the gist of this disclosure. In the above embodiment, the shape measuring unit 10 and the radiation source removal unit 30 are moved relative to the object W by the moving mechanism 40, but the embodiment is not limited to this. For example, the object W may be placed on a turntable that can rotate on the floor 2f, or on a stage mechanism that moves the object W relative to the shape measuring unit 10 and the radiation source removal unit 30.

[0044] <Note> The decontamination system 1 described in the embodiment can be understood, for example, as follows:

[0045] (1) The decontamination system 1 according to the first embodiment comprises: a shape measuring unit 10 capable of measuring the position and shape of an object W to be decontaminated; a dose distribution information acquisition unit 20 that acquires information on the distribution of radiation doses in the object W; a radiation source removal unit 30 that removes radiation sources from the object W; a moving mechanism 40 that moves the radiation source removal unit 30 relative to the object W; and a control device 70 that, based on the shape of the object W measured by the shape measuring unit 10 and the distribution information acquired by the dose distribution information acquisition unit 20, moves the radiation source removal unit 30 with the moving mechanism 40 and removes the radiation sources from the portion of the object W that has a radiation dose above a preset standard.

[0046] This allows for the removal of radiation sources without workers having to approach them. Furthermore, the radiation source removal unit 30 can be positioned relative to the object W in a way that is suitable for radiation source removal. There is no need to remove radiation sources from areas where the radiation level is below the standard, allowing for efficient radiation source removal. Therefore, the removal of contaminants from the object W can be carried out efficiently.

[0047] (2) The decontamination system 1 according to the second embodiment is the decontamination system 1 of (1), further comprising an object holding unit 50 which includes a holding member 51 capable of holding the object W and a holding member moving mechanism 52 for moving the holding member 51 relative to the radiation source removal unit 30.

[0048] This allows for efficient removal of the radiation source while the object is held in place by the object holding unit 50.

[0049] (3) The decontamination system 1 according to the third embodiment is the decontamination system 1 of (2), wherein the holding member 51 is detachable from the holding member moving mechanism 52.

[0050] This allows the holding member 51 to be replaced according to the radiation dose of the object W.

[0051] (4) The decontamination system 1 according to the fourth embodiment is any one of the decontamination systems 1 from (1) to (3), further comprising a recovery unit 60 for recovering the removed material removed from the target object W by the radiation source removal unit 30.

[0052] As a result, by recovering the removed material from the target object W using the recovery unit 60, it is possible to suppress the increase in radiation levels at the site where the radiation source is being removed due to the removed material. [Explanation of Symbols]

[0053] 1…Decontamination system 2… Decontamination building 2f…Floor 2t...roof 2w…Wall 3…Bass 8… Protective material 10…Shape measurement unit 20...Dose distribution information acquisition unit 30…Radiation source removal section 40...Movement mechanism 41... Rail 42…post 43... Lifting beam 44… Mounting platform 50... Object holding part 51…Retaining member 52... Holding member movement mechanism 53...Moving rail 60…Recovery Department 61... Suction duct 70...Control device 71…Information acquisition department 72...Program generation unit 73...Operation Control Unit W...Object

Claims

1. A shape measuring unit capable of measuring the position and shape of the object to be decontaminated, A dose distribution information acquisition unit that acquires information on the distribution of radiation doses in the aforementioned object, A radiation source removal unit for removing the radiation source from the aforementioned object, A moving mechanism for moving the radiation source removal unit relative to the object, A control device that, based on the shape of the object measured by the shape measuring unit and the distribution information acquired by the dose distribution information acquisition unit, moves the radiation source removal unit by the moving mechanism and removes the radiation source from the portion of the object that has a radiation dose above a preset standard, A decontamination system equipped with the following features.

2. A holding member capable of holding the aforementioned object, The object holding unit further comprises a holding member moving mechanism for moving the holding member relative to the radiation source removal unit. The decontamination system according to claim 1.

3. The retaining member is detachably attached to the retaining member moving mechanism. The decontamination system according to claim 2.

4. The system further includes a recovery unit for recovering the removed material that has been removed from the target object by the radiation source removal unit. The decontamination system according to claim 1 or 2.

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