RU2786203C1 - Method for a comprehensive examination of a block of protective tubes of a nuclear reactor and a device for its implementation - Google Patents

Abstract

FIELD: reactors.

SUBSTANCE: inventions group relates to a method and devices for monitoring the internals of a VVER-type reactor from the outside. A method for comprehensive inspection of the block of protective tubes of a nuclear reactor from the outside consists in taking readings when the block of protective tubes is removed from the reactor vessel and installed in the inspection shaft of the block of protective tubes using a bar. The bar is made in the form of a rectangular frame with at least two compartments with chamber modules in the form of metal boxes, where a television camera and an illuminator are located, and the bar is placed between the protective tube inspection shaft and the reactor vessel and readings are taken from the lower surface of the protective tube block using a bar in time of block movement from the reactor vessel to the inspection shaft. The ring device used for examination is made in the form of an annular frame with at least two compartments, and at least two supports are attached to the frame with their upper ends, and the compartments contain chamber modules in the form of metal boxes, where a television camera and an illuminator are located. The ring is installed on the top of the spacer of the inspection shaft of the protective tube block and readings are taken from the side surface of the protective tube block during installation of the block in the inspection shaft.

EFFECT: invention provides the ability to reduce the time of the control procedure by carrying it out simultaneously with the movement of the protective tube block from the reactor pressure vessel to the inspection shaft, as well as by simplifying the assembly, installation and dismantling of equipment for inspection, ensuring the availability of internal facilities during decontamination and operational reliability of the equipment.

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Description

SUBSTANCE: group of inventions relates to measuring equipment in the field of nuclear energy, in particular to a method and devices for monitoring internal devices of a VVER type reactor from the outside. This group of inventions is intended for carrying out automated remote control of the base metal and welded joints of the block of protective tubes (BZT) of the reactor by the method of visual and measuring control using television means in the period preceding operation and during the period of scheduled preventive maintenance.

The objects of BZT control are:

- the base metal of the key surfaces, contact surfaces of the support shoulder, including the measurement of the wear of the keys;

- welded connection of the shells of the supporting part to each other;

- welded connection of welding of the support shell to the middle plate;

- welded joints for welding dowels to the shell;

- surfaces of the lower grille, mating with the heads of the fuel assemblies;

- welded connection of welding of a conical shell to a cylindrical shell;

- welded connection of welding of the conical shell to the grille shell;

- welded connection of welding of the bottom plate to the shell;

- welded connection of welding of the plate of the middle to the upper shell of the semi-hull;

- surfaces of the keyways in contact with the keys of the middle shell of the SHVK, including measuring the wear of the keyways.

The control of the base metal and welded joints of the BZT should be carried out in order to obtain data on the state of the metal of the controlled areas during the commissioning of the reactor plant and during periodic monitoring during the operation of the NPP. The BZT provides placement and protection from the dynamic flow of the coolant of the control elements and assemblies of in-reactor detectors.

A device is known for a comprehensive examination of the elements of the control and protection system of a nuclear reactor according to patent RU2282261, containing a television camera, an illuminator, a means of moving a television camera, a system unit of a personal computer, a video monitor, characterized in that the device is equipped with additional television cameras and illuminators, mechanical units for turning television cameras and illuminators in the vertical and horizontal planes, one-coordinate rotary devices, a system for controlling the focus and scale of the lenses of a television camera, a system for controlling the luminous flux of illuminators, and a U-shaped instrument frame. The examination method consists in pointing television cameras and illuminators at the studied section of the rod with the help of rotary devices and taking readings, the rod also has the possibility of free vertical movement in the guide funnel, which as a result makes it possible to fully examine it. The disadvantages of the device and method for examining the rods of the control and protection system are the complexity of assembly and preparation for work, the need to stop the main technological operations for the duration of the control, the need to move, install and configure the control device for each controlled element of the control and protection system of a nuclear reactor, which makes this survey is not time efficient.

The closest to the claimed group of inventions in terms of the problem to be solved is the device for monitoring the internal devices of the reactor from the outside according to patent RU157811, containing a vertically oriented support frame and a trolley, as well as a pan-tilt television camera, characterized in that a rotary console is introduced, fixed in the upper part of the trolley, made with the possibility of movement along the vertical guides of the support frame, and the pan-tilt television camera is fixed at the end of the rotary console. The control method consists in installing a support frame with a winch over the reactor inspection shaft, moving a trolley with a tilt-and-turn television camera along the inspection shaft guides along a predetermined path, which ensures the control of the protective tube block. The disadvantages of the device and method of control are the complexity of assembly and preparation for work, large size, the need to stop the main technological operations for the period of control, the need to use a polar crane for control, which makes this control inefficient in terms of time. Also, large time and labor costs are required for the dismantling and decontamination of equipment after the inspection.

The proposed group of inventions solves the technical problem of eliminating these shortcomings, namely, it carries out a comprehensive examination of the technical condition of the elements of the control and protection system of a nuclear reactor in the form of a block of protective pipes from the outside without stopping the main technological operations for the duration of the control, which simplifies and speeds up the control process.

The technical result of the group of inventions is to reduce the time of the control procedure by carrying it out simultaneously with the movement of the block of protective tubes (BZT) from the reactor vessel to the revision shaft, as well as to simplify the assembly, installation and dismantling of equipment for monitoring, the availability of all objects during decontamination , in the operational reliability of the equipment.

The technical result is realized due to the following methods and design features of the group of inventions.

A method for a comprehensive inspection of a nuclear reactor pipe protection unit, including:

- installation on the top of the shaft of the revision of the spacer of the shaft of the BZT revision, containing at least two trunnions;

- installation of a ring on top of the BZT inspection shaft spacer to control the external cylindrical surface of the BZT;

- fixing at least two supports with the upper ends on the ring;

- fastening of at least two supports by the lower ends on the trunnions of the spacer;

- installation of a bar to control the BZT bottom along the way of its movement to the revision shaft;

- extraction of BZT from the reactor vessel;

- moving BZT to the revision shaft;

- taking readings from the lower surface of the BZT using a bar during the movement of the BZT from the reactor vessel to the inspection shaft;

- taking readings from the side surface of the BZT using the ring during the installation of the BZT into the revision shaft.

The ring for control of the outer cylindrical surface of the BZT contains:

- a metal frame in the form of a ring with at least two compartments, each compartment containing a camera module;

- at least two supports fixed with their upper ends on the ring;

- at least two camera modules, while the module contains a metal box with one wall made of transparent protective glass, inside which a television camera and a lighting system are located, and on one of the walls of the box there is a sealed connector for connecting a cable through which the camera module is connected to the control equipment through the switch.

The BZT bottom control bar contains:

- a metal frame in the form of a bar with at least two compartments, each compartment containing a camera module;

- at least two camera modules, while the module contains a metal box with one wall in the form of a transparent protective glass, inside which a television camera and a system of illuminators are located, and on one of the walls of the box there is a sealed connector for connecting a cable through which the camera module is connected to the equipment control via a switch.

The group of inventions is illustrated by drawings.

On FIG. 1 shows a schematic representation of a comprehensive inspection of the pipe protection unit (PCU) from the outside, where:

1 - block of protective pipes (BZT);

2 - side surface of BZT;

3 - lower surface of the BZT;

4 - reactor vessel;

5 - BZT revision shaft;

6 - spacer of the revision shaft;

7 - spacer trunnion;

8 - control bar;

9 - control ring.

The arrow shows the direction of movement of the BZT.

On FIG. 2 shows the lowering of the BZT into the revision shaft through the ring. The arrow shows the direction of movement of the BZT.

On FIG. 3 shows a view of the control ring, where:

10 - ring-shaped metal frame;

11 - compartment;

12 - chamber module;

13 - support;

14 - the upper end of the support;

15 - lower end of the support;

16 - switch.

On FIG. 4 shows a view of the control bar, where:

17 - rectangular metal frame;

18 - compartment;

12 - chamber module.

On FIG. 5 view of the camera module with a TV camera and illuminators:

19 - metal box;

20 - transparent wall;

21 - sealed connector;

22 - TV camera;

23 - illuminator.

On FIG. 5 on the left shows the front wall of the chamber module, on the right - the chamber module in section and its rear wall.

Preparation for inspection of the BZT (1) consists in installing rings (9) in the form of an annular metal frame (10) with compartments (11) for chamber modules (12). It should be noted that the revision shaft spacer (6) is installed above the BZT inspection shaft (5) once and then is not removed, but serves to fasten the BZT (1) on it during work with the reactor. Camera modules (12) are hermetic metal boxes (19), on one wall of which there is a transparent protective glass (20), on the other - a sealed connector (21) for connecting a cable, and inside there is a TV camera (22) and illuminators (23) in the form of an LED strip. The frame (10) consists of segments and is quickly assembled manually by employees into a ring on the upper edge of the shaft spacer (6), attached to it, and chamber modules (12) are installed in the compartments (11) by the same employees. In this case, the frame (10) is attached to the shaft spacer (6) using supports (13), the lower end (15) of which is mounted on the spacer pins (7), which are located on the outer side surface of the shaft spacer (6). The supports (13) are metal tubes, the upper end (14) of which is fixed on the ring (9), and the lower end (15) is mounted on the trunnions (7) of the spacer of the inspection shaft (6). The number of supports (13) and trunnions (17) must be at least two, because otherwise they will not fulfill their function of fastening the ring (9) to the spacer of the shaft (6), and they must also be located opposite each other. After installation, the ring (9) remains on the spacer (6) of the BZT inspection shaft (5) for the entire life of the NPP. The bar (8) in the form of a rectangular metal frame (17) with compartments (18) for chamber modules (12) is manually assembled by employees from segments and installed up to the revision shaft of the BZT (5), for example, on the plate of the internal shaft transportation device (UTSH), and in such a way that the edges of the plank (8) are directed to the walls of the canyon. In the compartments (18) of the rectangular frame (17), camera modules (12) are manually installed by employees. Camera modules (12) installed in compartments (11) and (18) of the respective frames (10) and (17) are connected to the control equipment through switches (16), which serve to reduce the number of cables going to the control equipment. At least two camera modules (12) must be installed in order to survey all surfaces of the BZT (1). Accordingly, the number of compartments (11) and (18) for chamber modules (12) must be at least two. Thus, the process of assembling and preparing equipment for examination is simplified in comparison with analogues. The equipment itself in the form of a ring and a bar is reliable in use, since there are no moving elements in their design.

The method of complex examination of BZT (1) is carried out as follows. BZT is removed from the reactor vessel (4) and moved to the BZT revision shaft (5). During the movement of the BZT above the bar (8) with the camera modules (12), the bottom surface (3) of the BZT is surveyed. When lowering the BZT into the revision shaft (5), it passes inside the ring (9) with chamber modules (12), and the side surface (2) of the BZT is surveyed. Compartments (11) and (18) for camera modules (12), respectively, in the bar (8) and ring (9) are located in such a way as to ensure the survey of all BZT surfaces. In this case, the operations of moving the BZT from the reactor vessel (4) to the revision shaft of the BZT (5) are carried out in any case, regardless of the need to perform control. Thus, a comprehensive examination of BCT does not take additional time and does not require the performance of separate operations specifically for control. The survey results are stored as digital images in the non-volatile memory of the control equipment. At the end of the shooting, the analysis of the received images is performed, and a conclusion is issued on the results of the control.

After the inspection, the equipment is dismantled and decontaminated. First, the chamber modules (12) are disconnected from the control equipment, then they are removed from the ring (9) and the bar (8), the bar is removed from the UTSh plate and disassembled manually. The ring (9) is located on the spacer (6) of the BZT inspection shaft (5) for the entire period of operation of the power unit and does not require dismantling, decontamination. Next, the chamber modules (12) and bar segments (8) are decontaminated. For decontamination, standard equipment of the NPP central hall is used - an ultrasonic bath. Chamber modules and bar segments are alternately placed in it for a certain time. The dismantling of the equipment is easy to perform, carried out manually by two or three employees, and does not require the use of a polar crane. Decontamination of equipment with access to all parts does not take much time.

As a result, the procedure for a comprehensive examination of the BZT does not take additional time, and preparation for the examination procedure for the installation of equipment and upon completion of the examination during its dismantling takes much less time than in analogues. The equipment used for testing in the form of a ring and a bar is reliable in use, since there are no moving elements in their design, which increases their performance.

Thus, the technical result is achieved - reducing the time of the control procedure, simplifying the process of assembly, installation and dismantling of equipment, the availability of all equipment objects during decontamination, and the operational reliability of the equipment.

An example of the implementation of the control method

The assembly and testing of the device for a comprehensive examination of the BZT was carried out on a full-scale simulator of the canyon of a VVER type reactor. A mounted ring of eight segments with eight supports and compartments for chamber modules was installed on the upper edge of the spacer of the BZT revision shaft so that the lower ends of the supports rested on the eight pins of the spacer. Two people installed 84 camera modules into the compartments for the camera modules of the ring, and connected them to the control equipment through switches. At this time, a bar in the form of a metal frame of three segments with compartments for chamber modules was installed on the UTSh slab in such a way that the edges of the bar were directed towards the walls of the canyon. The same two people installed 26 camera modules into the compartments for camera modules of the strip, and connected them to the control equipment through switches. The canyon simulator was filled with water. The BZT simulator was removed from the reactor vessel simulator, carried over the bar with chamber modules, and lowered through the ring with chamber modules into the BZT inspection shaft simulator. During the movement of the BZT above the bar with camera modules, the lower surface of the BZT was surveyed, and when the BZT was lowered into the revision shaft inside the ring with the camera modules, the side surfaces of the BZT were surveyed. The survey results were stored as digital images in the non-volatile memory of the control equipment. After the shooting was completed, the analysis of the received images was performed, and a conclusion was issued on the results of the control. Thus, a comprehensive survey of the BZT was carried out simultaneously with its movement from the reactor vessel to the inspection shaft without additional time spent on the survey, which reduced the control time, and hence the downtime of the power unit, by 14 hours.

After the survey, the canyon is drained and the procedure for dismantling and decontaminating the equipment begins. First, the chamber modules are disconnected from the control equipment, then they are removed from the ring and the bar, the bar is removed from the UTSh plate and disassembled manually for 10 minutes. The ring is located on the spacer of the revision shaft for the entire period of operation of the power unit and does not need to be dismantled and decontaminated. Next, the chamber modules and bar segments are decontaminated.

For decontamination, an ultrasonic bath was used - this is the standard equipment of the central halls of the nuclear power plant. Chamber modules and bar segments were alternately placed in it for 10 minutes each. At the same time, 20 chamber modules or one bar segment were in the ultrasonic bath. The control equipment was treated with alcohol for 20 minutes. The decontamination of all equipment was carried out by three people within 1 hour and 30 minutes.

Claims (3)

1. A method for a comprehensive examination of the block of protective tubes of a nuclear reactor of the VVER type from the outside, which consists in removing the block of protective tubes from the reactor vessel, installing it in the revision shaft of the block of protective tubes, taking readings using at least two cameras and illuminators, characterized in that a spacer of the inspection shaft is installed on the top of the inspection shaft, which contains at least two trunnions; mounted on trunnions, a camera and an illuminator are placed in the compartment, a bar with at least two compartments is installed between the inspection shaft of protective tubes and the reactor vessel, a camera and an illuminator are placed in the compartment, readings are taken from the lower surface of the block of protective tubes using a bar during the movement of the block from the reactor vessel to the revision shaft, then take readings from the side surface awns of the block of protective pipes with the help of a ring during the installation of the block in the revision shaft. 2. A bar for implementing the method according to claim 1, including the placement of a television camera and an illuminator, characterized in that it is made in the form of a rectangular frame with at least two compartments, the compartment contains a camera module, which is made in the form of a metal box with one wall of a transparent protective glass, a sealed connector is placed on the other wall of the box, and a television camera and an illuminator are placed inside the box. 3. A ring for implementing the method according to claim 1, including the placement of a television camera and an illuminator, characterized in that it is made in the form of an annular frame with at least two compartments, at least two supports are attached to the frame with their upper ends, a camera module is placed in the compartment, while the module contains a metal box with one wall of transparent protective glass, a sealed connector is placed on the other wall of the box, and a television camera and an illuminator are placed inside the box.

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