RU2353009C2 - Method of pipes extraction and associated device - Google Patents

Abstract

FIELD: nuclear power production industry.

SUBSTANCE: invention relates to nuclear power production industry and, particularly, to pipe extraction method when certain elements are replaced during nuclear reactor refueling. The invention also considers a device intended for pipes extracting. Multi-functional plug is installed once and not changed during spent pipe dismantling. The plug is installed by screwing its cylindrical part into the pipe. Counter-boring tool is centered by means of additional cylindrical plug surface. The weld joint connecting pipe with support is core-drilled. Plug opener with collet grip starts opening pipe holding the gripping part of plug. Pipe is extracted from supports by ball-locking grip holding the gripping part of the plug. The spent pipe is disposed together with the multi-functional plug. The multi-functional plug is manufactured in the shape of cylindrical rod with gripping head for pipe opening and extraction.

EFFECT: invention allows for widening technological possibilities of device and improves radiation safety.

3 cl, 4 dwg

Description

The invention relates to nuclear technology and can mainly be used for objects using atomic energy, in particular to a method for extracting liners (pipes) when replacing individual elements during overloading a nuclear reactor, in particular, on ships with a nuclear steam generating unit (APPU). In addition, this invention relates to the design of a device by which the extraction of sleeves (pipes) is carried out.

When unloading sleeves and pipes, in particular sleeves of emergency protection rods (A3), emergency sensors (ND), resistance thermometers (TS), make-up and spill pipes (PP) located on the reactor cover on ships with automatic control gear, for example, icebreakers use several types of plugs, guide rods, threaded jacks and adapters. The above operation includes the implementation of such stages of work as installing plugs after removing the rods A3, ND, TS, etc., cutting the seams, blasting the sleeves (pipes) and unloading them. At the same time, for each of the stages of work, individual plugs have been designed (to ensure biological protection), guide rods (for guiding the tool when cutting welds), demolition jacks and adapters for extraction, which are installed and removed one by one, as well as devices that carry out the work . In addition, the operations for unloading sleeves (pipes) are extremely radiation-hazardous, since they are associated with the very first depressurization of the primary circuit and therefore must be carried out as soon as possible and with the smallest reinstallations.

A known method of dismantling defective spent fuel assemblies (SFA) (RU No. 2253158, G21C 19/33, G21C 19/34, publ. 2005), in which remove the protective plug of the loading hole of the rotary plate, combined with one of the concentrically located in the pipe the board of the rows of cells with assemblies, determine all the defective assemblies located in this row, then, turning the rotary plate, center this loading hole relative to the head of the pencil case with the defective assembly and cut an annular groove through the body of the tube board, after which They complete the blasting of the canister with a defective assembly, put on the cylindrical surface of the canister put on a technological detachable spring ring and lower the canister back into the same cell of the tube plate. Next, the loading hole of the turntable is installed over each pencil case with a defective assembly in this row and all the above operations are repeated. At the end of these operations, through the loading hole, all the blown-up pencil cases with bushings and technological detachable spring rings are successively removed.

A feature of the above method is that it is carried out on a floating or coastal technical base, that is, it is not associated with the depressurization of the primary circuit. The disadvantage of this method is that in the process of performing all technological operations: removing the protective plug, cutting an annular groove in the body of the tube plate, detonating the pencil case with a defective assembly, removing all the damaged pencil cases, use their individual plugs, which are installed and removed alternately with adapters and devices, using which carry out work, the number of reinstallation of traffic jams increases, a significant amount of equipment is used and the process time increases.

A device is known for extracting a technological channel from a stepped path of a nuclear reactor (SU 1674654, G21C 19/26, publ. 1990), which comprises a channel gripping mechanism in the form of a housing with end coverage and an organ of cutting an annular seam mounted on the housing with an autonomous drive of rotation between the channel and its path in the form of a cutting head with symmetrical end cutters, and the cutting head is mounted on the housing of the gripping mechanism with an eccentricity about its axis.

The disadvantage of this device is that the installation of the cutting head, with which they cut the annular weld between the channel and the path to extract each technological channel from the path of the nuclear reactor, requires eccentricity, and its diameter is chosen by calculation based on the requirements for the quality of the cut of the weld , which leads to an increase in the complexity of the process.

A device for cutting pencil cases with defective spent fuel assemblies (RU No. 2220465, 7 G21C 19/33, G21F 5/008, publ. 2003), made of two coaxially arranged parts: a fixed base and a rotary platform, and on a fixed base one hole is made for centering the device and the input of the cutting tool in the form of a drilling head, and on the rotary platform there is a vertical-drilling machine mounted on two racks, and two holes are made radially located at an angle of 90 °, one of the cat ryh intended centering device, and the other - to enter the cutting tool.

The disadvantage of this device is that to remove canisters and covers with defective SFAs, it is necessary to ensure the alignment of the cutting head and the cutting of the annular groove with a cutting tool at the site of welding of the canister with the tube plate, which leads to an increase in the time required to complete the operation of the technological process and, accordingly, increase the harmful effects of radiation to the staff. Replacing the standard plugs of the nests in the rotary plate of the storage with removable plugs reduces the radiation safety of staff.

The problem solved by the invention is to perform all technological operations for the extraction of sleeves (pipes) using one multifunctional plug and to develop a device design for blasting and removing sleeves (pipes), which leads to a reduction in auxiliary equipment, a reduction in the time for operations, expansion technological capabilities, improving radiation safety.

When using the proposed invention can be obtained, in particular, the following technical results:

- reducing the duration of the process;

- reduction in the amount of equipment;

- lowering the dose loads on the personnel serving the equipment;

- reducing the release of radionuclides into the environment during the dismantling of sleeves (pipes).

This problem is solved by the fact that in the method of extracting sleeves (pipes), including killing holes in the sleeve (pipe) after dismantling the standard elements, cutting the weld that the sleeve (pipe) is welded to the rack, blasting the sleeve (pipe) from the rack by a sufficient amount , removing the sleeve (pipe) from the rack, according to the invention, the installation of the multifunctional plug is performed once without reinstalling when performing all operations to dismantle the spent sleeve (pipe) by screwing a cylindrical surface with a thread into the spent sleeve (pipe) with the possibility of providing mechanical fastening of the plug to the removable sleeve (pipe), center the drill bit by means of an additional cylindrical surface of the plug and ream the weld connecting the removable sleeve (pipe) with the rack, install a device for blasting with a collet gripper on the rack and carry out the detonation of the removable sleeve (pipe) for the gripping head located in the upper part of the cork, remove the spent sleeve (pipe) from the rack by a gripper with a ball lock Ohm for the aforementioned gripping head of the multifunctional plug.

It is advisable to send the spent sleeve (pipe) for disposal along with a multifunctional cork.

The problem is also solved by the fact that the device for implementing the method of extracting sleeves (pipes) is made in the form of a plug, according to the invention, the plug is made multifunctional in the form of a cylindrical rod, the upper part of which is made with a gripping head for blasting and subsequent extraction of the spent sleeve (pipe), with additional a cylindrical surface in the form of a belt for centering the countersink, with a cylindrical surface with a thread for mechanical fastening of the cork to the extracted spent sleeve (pipe) and of threading the labyrinth seal with the possibility of reducing the release of radionuclides into the environment, the lower part of the plug is made in the form of a cylinder of the required length, located inside the extractable spent sleeve (pipe) and providing radiation protection for the personnel serving the equipment.

The technical result consists in the fact that when working with each of the dismountable elements located on the reactor cover, in particular a vessel with automatic gearboxes, during overload, one plug design is used instead of individually designed plugs for each process, thereby reducing the duration of the process and reducing the number of equipment, and also reduces the number of openings of the primary circuit during the process above each of the elements.

The implementation of a cylindrical surface with a thread in the plug design allows it to be screwed into a removable spent sleeve (pipe), which, in contrast to a simple installation, provides biological protection and reduces the release of radionuclides through the thread into the environment when dismantling spent sleeves (pipes).

The implementation of the lower part of the cork in the form of a cylinder of the required length ensures a reduction in dose loads on personnel serving the equipment.

During the blasting and subsequent removal of the spent sleeve (pipe), the plug acts as a gripping head, when cutting joints, the plug acts as a centering drill on an additional cylindrical surface, when installed, the plug performs biological protection and mechanical fastening to the sleeve by a cylindrical surface with a thread that acts as a labyrinth compaction, which indicates, in particular, its versatility and thereby the expansion of its technological capabilities.

The invention is illustrated by the drawings shown in figures 1-4:

figure 1 is a General view of the installed multifunctional plugs in the extractable sleeve (pipe);

figure 2 is a General view when conducting countersinking of the weld using a multifunctional tube for centering the countersink;

figure 3 is a General view when conducting blasting of the liner (pipe) using a multifunctional plug as a gripping and traction element;

4 is a General view of the unloading of the sleeve (pipe) together with a multifunctional plug using a gripper.

The device for extracting the sleeves (pipes) is a multifunctional plug 1 (hereinafter referred to as the plug), made in the form of a cylindrical rod, the upper part of the plug 1 contains a gripping head 2, providing detonation and subsequent removal of the spent sleeve (pipe) 3, an additional cylindrical surface 4 in the form belts with the possibility of centering the vertical drill 5, a cylindrical surface with a thread 6 for mechanical fastening to the extracted spent sleeve (pipe) 3 and creating a labyrinth seal with the possibility of providing eniya reduce radionuclide release into the environment during the performance of operations with the sleeve (tube) 3.

The lower part of the plug 1 is made in the form of a cylinder 7 of the required length located inside the retrievable sleeve (pipe) 3, which provides personnel protection from dose loads.

The proposed method for extracting sleeves (pipes) can be carried out as follows.

Multifunctional plugs 1 are installed once without reinstalling during cutting, blasting and removal into all spent sleeves (pipes) on the reactor lid.

The plug 1 is screwed into the extractable spent sleeve (pipe) 3 (FIG. 1) located in the rack 8 of the reactor cover and welded to it, by means of a cylindrical surface with thread 6 for mechanical attachment to the removable sleeve (pipe) 3 and the creation of a labyrinth seal.

Then perform the centering of the vertical drill 5 (figure 2) on an additional cylindrical surface (girdle) 4 of the plug 1 and cut the weld 9 in the place of welding of the sleeve (pipe) 3 to the rack 8.

Then, using the device for blasting 10 (Fig. 3), which is a hydraulic power device with a grip (collet) 11, the spent spent sleeve (pipe) 3 is blown up by the gripper head 2 of the tube 1. In this case, water is supplied through the nozzle 12. under pressure from the pumping station (not shown in FIG.), moving the piston 13 to the upper position together with the collet gripper 11. When moving the collet gripper 11 to the upper position, the ring sleeve 14 compresses the collet 11, which in turn compresses the gripping head 2 pr shell 1 and with further movement occurs undermining the sleeve (pipe) 3 through the plug 1.

The blasting device 10 is returned to its original state by moving the piston 13 to its lower position, while the collet 11 is unclenched, releasing the gripping head 2 of the plug 1. For each type of removable spent sleeves (pipes) 3, their interchangeable support 15 is installed on the rack 8, the design of which depends on rack design 8.

Next, using the gripper 16 (Fig. 4), the spent sleeve (pipe) 3 is dismantled from the rack 8 behind the gripper head 2 of the plug 1. The gripper 16 is made of a ball type. Its response to alternate closing and opening occurs from the control sleeve 17, fixed from spontaneous rotation, by a ball lock 18. The control sleeve 17 is mounted by means of bearings 19 on the inner rod 20 with the possibility of rotation. When the inner rod 20 is pushed into the gripping head 2 of the plug 1, the outer housing 21 of the gripper 16 is moved down and screw 22, mounted on it, at the end of the movement enters the oblique groove 23 of the control sleeve 15 and rotates it at a certain angle. When the outer housing 21 of the capture 16 upward, the screw 22 enters the long or short grooves 24 of the control sleeve 17, respectively fixing the closed or open position of the capture 16, and accordingly the cone 25 of the outer housing 21 of the capture 16 or closes the balls 26 located in the recesses 27 of the inner rod 20, or leaves the balls open.

Claims (3)

1. A method of extracting sleeves (pipes), including killing the hole in the sleeve (pipe) after dismantling the standard elements, cutting a weld with which the sleeve (pipe) is welded to the stand, blasting the sleeve (pipe) from the stand by a sufficient amount, removing the sleeve (pipe) ) from the rack, characterized in that the multifunctional plug is installed once without reinstalling when performing all operations to dismantle the spent sleeve (pipe) by screwing a cylindrical surface with thread into the spent sleeve (pipe) to ensure cross-section of mechanical fastening of the multifunctional plug to the removable sleeve (pipe), center the countersink by means of an additional cylindrical surface of the multifunctional plug and countersink the weld connecting the extractable sleeve (pipe) with a stand, install a device for blasting with a collet grip and undermine the extractable sleeve (pipe) for the gripping head of the multifunctional plug, the spent sleeve (pipe) is removed from the rack by a gripper with a ball lock for the gripping head nogofunktsionalnoy cork. 2. The method of extracting sleeves according to claim 1, characterized in that the spent sleeve (pipe) is sent for burial together with a multifunctional stopper. 3. A device for extracting sleeves (pipes), made in the form of a tube, characterized in that the tube is made multifunctional in the form of a cylindrical rod, the upper part of which is made with a gripping head for blasting and subsequent extraction of the spent sleeve (pipe), with an additional cylindrical surface in in the form of a belt for centering the countersink, with a cylindrical surface with a thread for mechanical fastening of the multifunctional plug to the extracted spent sleeve (pipe) and creating a labyrinth thread seals, providing a decrease in the release of radionuclides into the environment, the lower part of the multifunctional plug is made in the form of a cylinder of the required length, located inside the extractable spent sleeve (pipe) and providing radiation protection for personnel serving the equipment.

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