Waste cable disposal system

Abstract

To provide technical means enabling further volume reduction of an amount of radioactive wastes.SOLUTION: A waste cable processing system comprises: a cable cutting device 1 for cutting a cable consisting of an internal material containing a copper material and a coating of the internal material, into a prescribed length; a surface cleaning device 2 for cleaning the surface of the cut cable; a first processing system 10 including a cable coating peeling device 11 for segregating the cable into the coating and the internal material and disposing the coating as a radioactive waste; a second processing system 20 including a chipping segregation device 21 for chipping a processing object into chips to segregate the chips into the copper material and other materials, and disposing the copper material from other materials, in a state of being segregated from each other; and a contamination discriminating / object carrying-out monitor 3 for discriminating presence / absence of contamination of contaminated cables, sorting the cables on the basis of, a discrimination result, supplying cables with contamination to the first processing system 10 and supplying cables without contamination to the second processing system 20.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a system for processing waste cables generated in nuclear power plants. [Background technology]

[0002] The total length of cables laid at nuclear power plants currently in the decommissioning stage is said to be over 2,000 km. Some of these cables have become surface contaminated by radioactive dust in the atmosphere during their long operation periods. If the cables were disposed of as is, they would all become radioactive waste, and if packed into drums, the amount would amount to tens of thousands of cables. However, the majority of contaminated cables only have contaminated sheathing, and the interior of the cables, especially the copper wires, are free of radioactive material and are reusable and valuable.

[0003] Therefore, Patent Document 1 discloses an apparatus for stripping the coating from a cable while automatically transporting the cable. The apparatus disclosed in Patent Document 1 strips the coating from the cable and can discard the stripped coating as radioactive waste, thereby reducing the amount of radioactive waste. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2021-052506 Summary of the Invention [Problem to be solved by the invention]

[0005] However, even if the device disclosed in Patent Document 1 is used, the amount of radioactive waste is still large, and further volume reduction is desired.

[0006] The present invention has been made in view of the above-described problems, and aims to provide a technical means that enables further reduction in the volume of radioactive waste. [Means for solving the problem]

[0007] The waste cable disposal system of this invention is a system including a cable cutting device that cuts a cable consisting of an internal structure containing copper material and the sheath of this internal structure to a predetermined length, a surface cleaning device that cleans the surface of the cut cable, and a cable sheath stripping device that separates the cable into the sheath and the internal structure, and is characterized by including a first processing system that disposes of the sheath as radioactive waste, a second processing system that includes a chipping sorting device that shreds the material to be processed into chips and separates the chips into copper material and other materials, and separates and disposes of the copper material and other materials, and a first contamination determination / item removal monitor that determines whether the cleaned cable is contaminated or not, sorts the cable based on the determination result, and supplies contaminated cables to the first processing system and uncontaminated cables to the second processing system. [Effects of the Invention]

[0008] According to this invention, the surface of the cable is cleaned, and the presence or absence of contamination in the cable after cleaning is determined. Only the contaminated cable is supplied to the first processing system, and the cable sheath is disposed of as radioactive waste, thereby significantly reducing the amount of radioactive waste. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a block diagram showing a configuration of a waste cable processing system according to an embodiment of the present invention; DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing the configuration of a waste cable disposal system according to one embodiment of the present invention. In this waste cable disposal system, the surfaces of all cables are first cleaned, and then the presence or absence of contamination in all cables after cleaning is determined. The coating of contaminated cables is stripped and disposed of as radioactive waste. This significantly reduces the amount of radioactive waste while ensuring safety. In addition, the waste cable disposal system according to this embodiment also determines the presence or absence of contamination in the contents of the cables after the coating is stripped, and contaminated contents are disposed of as radioactive waste. This further enhances safety. In FIG. 1, the cable cutting device 1, surface cleaning device 2, contamination determination / item removal monitors 3 and 16, cable coating stripping device 11, compression / volume reduction device 13, chipping / sorting device 21, and clearance inspection device 22 are all automatic or semi-automatic devices, while the other devices are operated manually. In addition, in FIG. 1, articles are automatically transported in the section between the cable cutting device 1 and the surface cleaning device 2, the section between the surface cleaning device 2 and the contamination determination / article discharge monitor 3, and the section between the contamination determination / article discharge monitor 3 and the cable sheath stripping device 11, but articles are manually transported in other sections.

[0011] Cables in nuclear power plants are cut to lengths that take into account workability and transportability, specifically, lengths of approximately 1 to 2 meters, using a cable cutting device 1. More specifically, the cable cutting device 1 clamps the cable between an automatic transport device, specifically, two pairs of rollers driven by a motor, and feeds it forward, measuring the amount of cable movement with a sensor. The device then stops feeding the cable at a predetermined length and automatically cuts the cable. Cutting methods include shears, rotary blades, and laser cutters. The automatic transport device, consisting of two pairs of rollers, has its spacing adjusted to match the cable's thickness and applies an appropriate thrust to the cable. Multiple sets of the automatic transport device, each consisting of two pairs of rollers, are provided depending on the transport distance. This automatic transport device may be used to transport cables within other equipment, as described below, and may also be used to transport cables between various pieces of equipment.

[0012] The cut cables, each 1 to 2 meter long, are automatically transported to the surface cleaning device 2. The automatic transport method may be to sandwich the cable between two pairs of rollers and send it out, or to load it onto a conveyor and send it out. In the surface cleaning device 2, the cable is sandwiched between two pairs of rollers driven by a motor and sent out, while automatically cleaning and removing dust and foreign matter from the cable surface using high-pressure water, a dry brush, etc. The cleaned cable is then automatically transported to the contamination detection / item removal monitor 3.

[0013] The contamination determination / item discharge monitor 3 includes a radiation detection unit that measures the contamination density on the surface of the cable. This radiation detection unit is composed of, for example, a four-sided box-shaped member consisting of four plate-shaped radiation detectors and a box-shaped shielding plate that surrounds this member to reduce the influence of external radiation. The radiation detection unit measures the radioactivity value as the cable passes through the four-sided box-shaped member. Multiple radiation detection units are arranged in the cable feed direction depending on the required detection speed. The cable transport means may be a means that sandwiches the cable between two pairs of rollers and feeds it, or it may be a conveyor system that places the cable on a tray with a thin metal mesh structure on the bottom and feeds the tray.

[0014] The contamination determination and goods removal monitor 3 determines whether or not there is contamination by comparing the contamination density on the cable surface measured by the radiation detection unit with a threshold value. Here, the threshold value is the regulatory value of 40 Bq / cm. 2 Alternatively, the limit may be set to a safe level (for example, 1 / 10 of the regulated value) taking into consideration the ambient dose rate, errors in the radiation detector, etc. The contamination determination / item removal monitor 3 sorts the cables based on the result of determining whether or not they are contaminated, and those that are contaminated (i.e., those with a contamination density higher than the threshold) are automatically transported to the first treatment system 10, while those that are not contaminated (i.e., those with a contamination density lower than the threshold) are manually transported to the second treatment system 20.

[0015] The following describes the first processing system 10. The first processing system 10 includes a cable sheath stripping device 11. A cable determined to be contaminated is automatically transported from the contamination determination / item delivery monitor 3 to this cable sheath stripping device 11.

[0016] The cable sheath stripping device 11 uses a cutting unit such as a rotary blade, ultrasonic cutter, or laser cutter to make one or more pairs of slits along the entire length of the cable at opposing positions on the circumference of the cable sheath. At this time, the cable is sandwiched and fed between two pairs of rollers driven by a motor, providing a driving force that resists the cutting resistance of the blades that make the slits in the sheath.

[0017] The cable sheath stripping device 11 performs a stripping process by stripping the sheath from the cable that has passed through the cutting section and separating the cable into the sheath and the internal components. Various means can be used for this stripping process. For example, a pair of wedges may be used, which insert the tip of a pair of wedges into a pair of slits made in the sheath at the cutting section from the opposite direction to the cable feeding direction and separate the sheath into a first part and a second part on either side of the slits.

[0018] The separated first and second parts of the sheath are stored as contaminated material in a contaminated material tray provided outside the cable sheath stripping device 11. Meanwhile, the internal contents are stored in the internal contents tray. The internal contents are sent to the contamination determination / item discharge monitor 16. The contamination determination / item discharge monitor 16 measures the contamination density of the internal contents of the cable and compares it with a threshold value to determine whether the internal contents are contaminated or not. Internal contents determined to be uncontaminated by the contamination determination / item discharge monitor 16 are then transported as uncontaminated material (equivalent to industrial waste) to the second treatment system 20, which is an uncontrolled area of ​​the power plant. Meanwhile, internal contents determined to be contaminated are transported to the drum packing section 12.

[0019] The sheath stored in the contaminated material tray by the cable sheath stripping device 11 and the internal contents determined to be contaminated by the contamination determination / item discharge monitor 16 are transported to the drum packing section 12. In the drum packing section 12, the sheath and internal contents are packed into drums. In the compression volume reduction device 13, the internal contents or sheath packed into the drums are reduced in volume together with the drums using a compressor. In the drum packing section 14, these reduced-volume drums are packed into further drums, and the volume of each drum is reduced by a compressor. Then, in the radioactive waste disposal section 15, these reduced-volume drums are stored as low-level radioactive waste.

[0020] Next, the second processing system 20 will be described. The second processing system 20 includes a chipping and sorting device 21. Cables determined to be uncontaminated by the contamination determination / item discharge monitor 3 and internal contents determined to be uncontaminated by the contamination determination / item discharge monitor 16 are transported to this chipping and sorting device 21. The chipping and sorting device 21 shreds the cables or cable internal contents into chips, and separates the chips into copper and other materials using a sorting method that utilizes the difference in specific gravity of the materials, such as winnowing. The copper materials are then verified to be below the clearance level by a clearance inspection device 22 and disposed of as valuable resources in a copper material disposal unit 23. The other materials are incinerated as waste plastic in an incinerator 24 or disposed of as industrial waste in a general industrial waste disposal unit 25. When waste plastic is incinerated in an incinerator 24, the volume reduction rate can be increased to approximately 90%. A higher volume reduction rate reduces the amount of land required for storage until disposal. However, if there is no such requirement, the waste plastic material can be disposed of as industrial waste in the general industrial waste disposal section 25 without being incinerated.

[0021] According to the embodiment described above, the surfaces of all cables are cleaned, the presence or absence of contamination in all cables after cleaning is determined, and the sheaths of contaminated cables are stripped and disposed of as radioactive waste (subject to treatment by the radioactive waste disposal unit 15). This significantly reduces the amount of radioactive waste while ensuring safety. Furthermore, the cost of stripping the sheaths from contaminated cables and treating them as radioactive waste can be significantly reduced. Furthermore, the storage space required for radioactive waste can be significantly reduced. Furthermore, according to this embodiment, the copper wires constituting the cables are removed to reduce the volume, which can be sold as valuable resources. Furthermore, in this embodiment, the processes from cutting the cables to separating the cables into sheaths and internal components are performed by automated equipment, significantly reducing the number of workers and the risk of radiation exposure during the process. Furthermore, the equipment and transporting devices for cables that may be contaminated or have been determined to be contaminated are automatic or semi-automatic, thereby reducing radiation exposure for workers.

[0022] <Other embodiments> Although one embodiment of the present invention has been described above, other embodiments of the present invention are also possible, for example as follows.

[0023] (1) In the above embodiment, the drum packing unit 12 is provided in the waste cable processing system, but this drum packing unit 12 may be omitted, and the compression volume reduction device 13 may also serve as the drum packing unit 12. In other words, the sheath discharged from the cable sheath stripping device 11 and the contaminated internal materials discharged from the contamination determination / item discharge monitor 16 may not be collected in the drum packing unit 12, but may be collected directly in the compression volume reduction device 13 and compressed and reduced in volume.

[0024] (2) In the above embodiment, the cable cutting device 1, surface cleaning device 2, contamination determination / item discharge monitors 3 and 16, cable sheath stripping device 11, compression / volume reduction device 13, chipping sorting device 21, and clearance inspection device 22 are automatic or semi-automatic devices, while the other means are manual, but the other means may be automatic or semi-automatic devices. Also, in the above embodiment, articles are automatically transported in the section between the cable cutting device 1 and the surface cleaning device 2, the section between the surface cleaning device 2 and the contamination determination / item discharge monitor 3, and the section between the contamination determination / item discharge monitor 3 and the cable sheath stripping device 11, and are manually transported in other sections, but articles may be automatically transported in other sections. [Explanation of symbols]

[0025] 10...First treatment system, 20...Second treatment system, 1...Cable cutting device, 2...Surface cleaning device, 3,16...Contamination determination / item removal monitor, 11...Cable sheath stripping device, 12,14...Drum filling section, 13...Compression volume reduction device, 15...Radioactive waste disposal section, 21...Chipping sorting device, 22...Clearance inspection device, 23...Copper material disposal section, 24...Incinerator, 25...General industrial waste disposal section.

Claims

1. a cable cutting device that cuts a cable consisting of an internal object containing a copper material and a coating of the internal object to a predetermined length; a surface cleaning device for cleaning the surface of the cut cable; a first treatment system including a cable sheath stripping device that separates a cable into a sheath and internal components, the first treatment system disposing of the sheath as radioactive waste; A system including a chipping and sorting device that shreds the material to be treated into chips and separates the chips into copper material and other materials, and a second treatment system that separates the copper material and other materials for disposal; a first contamination determination / item removal monitor that determines whether or not the cleaned cables are contaminated, sorts the cables based on the determination result, and supplies contaminated cables to the first processing system and non-contaminated cables to the second processing system; A waste cable disposal system including:

2. The waste cable processing system of claim 1, wherein the first processing system has a second contamination determination / item removal monitor that determines whether the internal contents separated by the cable sheathing stripping device are contaminated, sorts the internal contents based on the determination result, and supplies the uncontaminated internal contents to the chip sorting device, and the sheathing separated by the cable sheathing device and the internal contents determined to be contaminated by the second contamination determination / item removal monitor are disposed of as radioactive waste.

3. 3. The waste cable processing system according to claim 1, wherein the second processing system disposes of the copper material separated by the chipping sorting device as a valuable resource, and incinerates or disposes of materials other than the copper material as general industrial waste.

4. a first automatic transport device that transports the cable between the cable cutting device and the surface cleaning device; a second automatic transport device that transports a cable between the surface cleaning device and the first contamination determination / item delivery monitor; a third automatic transport device that transports the cable between the first contamination determination / item discharge monitor and the cable sheath stripping device; The waste cable disposal system according to any one of claims 1 to 3, comprising:

5. The waste cable processing system described in claim 3, wherein the second processing system has a clearance inspection device that confirms that the copper material separated by the chipping sorting device is below the clearance level, and disposes of copper material that is below the clearance level as valuable material.

6. 2. The waste cable disposal system according to claim 1, wherein the device for handling cables that may be contaminated or cables that have been determined to be contaminated and the transport device are automatic or semi-automatic.

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