RU2786747C1 - Manipulator for moving an ultrasonic transducer in a fast neutron reactor with a liquid metal coolant - Google Patents

Abstract

FIELD: ultrasonic transducer moving manipulators.

SUBSTANCE: invention relates to a manipulator for moving an ultrasonic transducer in a fast neutron reactor with a liquid metal coolant. The device contains a fixed housing with a drive for angular movement, made mainly in the form of a tube with an internal cavity, which houses an ultrasonic transducer with a rope drive for vertical movement. Inside the fixed body there is a swivel guide tube, in which a protective plug is permanently installed with the possibility of engaging it during operation with the ultrasonic transducer and moving together with it, the connection of the transducer with the guide tube is carried out constantly on the entire vertical stroke of the ultrasonic transducer, and the connection of the ultrasonic transducer is carried out using sealed connector and tape-chain cable guide.

EFFECT: increasing the accuracy of the angular position of the ultrasonic beam and the height position of the ultrasonic transducer, increasing the accuracy of determining the coordinates of a foreign object above the reactor core, as well as reducing the labor intensity and increasing the safety of the maintenance personnel during the installation (dismantling) of manipulator equipment and when performing measurements.

8 cl, 8 dwg

Description

The invention relates to the field of nuclear engineering, in particular to devices for manipulators of a sound imaging system (hereinafter referred to as a manipulator) used to determine and record the coordinates of foreign objects located in the space between the ends of the heads of the core assemblies and the lower marks of the devices passing through the rotary plugs and the CPS column , prior to refueling and, if necessary, during refueling of sodium-cooled fast reactors.

There are at least two groups of ultrasonic (US) control systems in sodium-cooled fast reactors.

In one of the ultrasound systems, the emitter and receiver are located outside the reactor vessel and the signal to and from them is transmitted through a waveguide - a tube filled with liquid metal (see, for example, patents FR 2600201, IPC G21C 17/06 and GB 1488478, IPC G21C 17 /00). The technical problems of the known systems are the complexity of the technological process of measurements associated with the presence of additional auxiliary sodium and vacuum systems for the phased filling of the waveguide with a liquid metal coolant, reduced reliability of the reactor, since the sodium of the primary circuit is removed outside the reactor vessel, as well as the low accuracy of determining the coordinates of foreign objects due to with the removal of the transducer from the place of measurement.

In the second group, the ultrasonic emitter and receiver are located directly in sodium, inside the reactor vessel, and a special device, a manipulator, is required to deliver the ultrasonic emitter and receiver to the vessel.

The proposed device belongs to the second group of ultrasonic control systems.

The manipulator of the sound vision system is intended for:

- for delivery of ultrasonic transducers (USP) to the inspected zone of the reactor;

- to guide the ultrasonic beam in a given direction, in the horizontal and vertical planes of space;

- to remove the SPD from the sodium coolant to a zone with a low temperature for the duration of the reactor's operation at power.

A sound imaging device for a nuclear reactor with a liquid metal coolant is known (see, for example, RF patent No. 1528235, IPC G21C 17/00).

The device contains a rod, the lower end of which has a flange. The rod is located with the possibility of longitudinal movement in the annular ledge of the hollow body. The flange, hollow body with annular protrusions and seals form a hermetic chamber filled with liquid metal, identical to the reactor coolant. In a sealed chamber, in liquid metal, there is always an ultrasonic transducer (USP) with a membrane, fixed on a rod. When using the device in a nuclear reactor, the lower part of the hollow body is loaded into a liquid metal coolant. The drive, rotating the nut, moves the rod until the SPD completely exits the hollow body. In this case, the sealed chamber opens, the liquid metal coolant from it is mixed with the reactor coolant, forming a homogeneous medium for ultrasound. At the end of the work, by removing the rod into the hollow body, the hermetic chamber is sealed, leaving a part of the liquid metal coolant in it. Its excess flows through the channels of the annular ledge. Thus, the liquid metal is constantly in contact with the USP membrane.

The technical problems of the known technical solution are:

- insufficient accuracy of the angular guidance of the ultrasonic beam, and, as a result, the difficulty in determining the coordinates of a foreign object above the active zone;

- insufficient accuracy of the altitude position of the ultrasonic transducer;

- low maintainability, since when dismantling the manipulator from the reactor, it is necessary to provide protective containers and sealing protective structures;

- the complexity of the design, since the liquid metal coolant is sealed in a sealed chamber through movable seals;

- low reliability, since the ultrasonic transducer (USP) is constantly in the liquid metal.

A device for sound imaging of a nuclear reactor with a liquid metal coolant, an ultrasonic fluoroscope (Japan's application No. JP S5697816A, IPC G01B 17/00, G21C 17/08), the manipulator of which contains a body that can move up and down, and a holder with ultrasonic emitters and a receiver, externally connected by means of a folding linkage. The inner cavity of the body is hermetically connected with the help of bellows to the inner cavity of the holder. The signal cable from the ultrasonic emitters and the receiver passes through the bellows and through the rollers goes into the housing and then goes out of the reactor. The housing is connected to the vertical movement control rod by means of a ball screw and further to the drive motor. The drive motor is located in the drive unit, and the drive unit body is connected to the hoist with a cable. There is also a separate device for angular rotation of the housing. All equipment is placed in a casing, at the lower end of which a damper is installed. Before the operation of the manipulator, the casing with the equipment is stored outside the reactor. To carry out the work, the casing is installed on a small rotary plug of the reactor. The manipulator is used when the sodium temperature in the reactor is low, during reactor refueling or maintenance. After the manipulator is installed, gas is replaced in its internal cavity, the damper is torn off and the body with the lever mechanism and the holder is introduced into the reactor in a straight line. The drive motor is then turned on to pull up the arm and bend the body and holder into an L-shape. Next, the rotating plug of the reactor and the lever are combined and rotated by a separately installed drive device, and the entire upper surface of the core is scanned by transmitting and receiving ultrasonic waves. An image of the top surface of the core can be projected onto a separately mounted cathode ray tube.

The technical problems of this manipulator are:

- safe rotation of the rotary plugs is not ensured, since the manipulator scans the space precisely during the rotation of the rotary plugs;

- insufficient accuracy of the angular guidance of the ultrasonic beam, and, as a result, the difficulty in determining the coordinates of a foreign object above the active zone;

- insufficient accuracy of the altitude position of the ultrasonic transducer;

- low maintainability, since when dismantling the manipulator from the reactor, it is necessary to provide protective containers and sealing protective structures;

- insufficient reliability due to the possibility of failure of the drive of the folding lever or the tight connection of the connecting mechanism and the housing.

The technical result of the invention is to increase the accuracy of the angular position of the ultrasonic beam and the height position of the ultrasonic transducer and, consequently, to increase the accuracy of determining the coordinates of a foreign object above the reactor core, as well as to reduce the labor intensity and increase the safety of the work of maintenance personnel during the installation (dismantling) of manipulator equipment and when taking measurements.

The specified technical result is achieved by the fact that in the manipulator for moving the ultrasonic transducer in a fast neutron reactor with a liquid metal coolant, containing a fixed body, made mainly in the form of a pipe with an internal cavity, an ultrasonic transducer is placed in it with a rope drive of vertical movement, with a drive for angular movement of the body, according to the proposed invention, the device, inside the fixed body there is a rotary guide tube, in which a protective plug is permanently installed with the possibility of engaging it during operation with the ultrasonic transducer and moving together with it, the connection of the transducer with the guide tube is carried out constantly throughout the entire vertical stroke of the ultrasonic transducer , and the connection of the ultrasonic transducer is carried out using a sealed connector and a tape-chain cable guide.

The manipulator can be equipped with gates with drives for cutting off the inner cavity of the manipulator from the cavity of the reactor and valves for replacing the medium in the inner cavity of the manipulator.

The manipulator can be equipped with devices for tensioning and constant control of the tension of the drive rope.

The ultrasonic transducer can be equipped with a temperature control sensor.

Preferably, the protective plug in the upper position and during its vertical movement is engaged with the guide tube and is a guide for the ultrasonic transducer.

Preferably, the ultrasonic transducer has a pivoting device relative to the drive cable and the tape-cable guide.

Preferably, the SPD cable and the cable from its temperature control sensor are located in a blind pipe, the upper end of which is above the coolant level in the reactor when the SPD is in the lower extreme position, which excludes contact of the liquid coolant with power and control cables.

The angle of rotation of the guide tube can be limited within predetermined limits.

The essence of the claimed invention is illustrated by drawings, which show: in Fig. 1 is a longitudinal section of the proposed manipulator, in Fig. 2 - the location of the USP in the reactor, in Fig. 3 - element B (enlarged image), in Fig. 4 - element B (enlarged image), in Fig. 5 - element G (enlarged image), in Fig. 6 - section D - D, in Fig. 7 - section E - E, in Fig. 8 - section Zh - Zh.

Two manipulators are installed in plug 1 under the horizontal sound vision mechanisms in branch pipe 2 of the BN-800 reactor vessel outside of the rotary plugs.

Each manipulator contains the following main components: an ultrasonic transducer (USP) 3, a guide tube 4, a drive 5 for turning the guide tube 4, a drive 6 for vertical movement of the USP 3, an upper gate 7, a lower gate 8, a rope tension control device 9 10, a rod 11, hermetic case 12, protective plug 13.

During the operation of the reactor at power, the upper part of the manipulator, limited by the hermetic housing 12, the drive 6 and the gate 7, located above the plane of the connector A between the upper gate 7 and the lower gate 8, is located on the stand of the central hall, where all the necessary pre-installation checks are performed and, if necessary, adjustments.

Prior to the operation of the manipulator, a sealing plug from the set of tools and accessories (not shown in the drawings) is installed on the lower gate 8 directly in the reactor. A protective plug 13 is permanently installed in the guide tube 4. The protective plug 13 is fixed in the guide tube 4 by screws 14 located in the lower part of the body 15 of the lower gate 8. The lower gate 8 is in the closed position.

Before carrying out work on reloading the reactor, the upper part of the manipulator is dismantled from the stand of the central hall and installed on the lower gate 8. The upper gate 7 opens. Through valves 16, the gas medium in the inner cavity of the upper part of the manipulator is replaced from air to argon. The bottom gate opens 8.

The vertical movement in the sealed housing 12 and the guide tube 4 of the rod 11, consisting of the upper housing 17 with rollers 18, the pipe 19, the lower housing 20 with the ultrasonic transducer 3, is carried out using a rope 10, which is connected to a rotary device 21 located in the upper part of the upper housing 17. The other end of the rope 10 through the block of tension rollers 22 and the device 9 for controlling the tension of the rope 10 is connected to the drum 23 of the drive 6 of the vertical movement of the UZP 3.

The UZP 3 is lowered until the lug 24 in the lower part of the lower body 20 joins the hole 25 in the upper part of the protective plug 13. Through the mounting holes 26 in the body 15 of the lower gate 8, the lower body 20 of the UZP 3 is connected to the protective plug 13 using a pin 27 and a nut 28. Screws 14 are unscrewed from the housing 15 until the protective plug 13 exits the groove 29. Further lowering of the USP 3 occurs together with the protective plug 13.

When lowering the USP 3 after engagement with the protective plug 13, the groove 30 in the protective plug 13 first interacts with the guide bars 31 installed on the inner surface of the guide tube 4. With further lowering, the groove 30 in the protective plug 13 disengages from the guide bars 31. The groove 32 in the lower housing 20 of the UZP 3 engages with the guide bars 31 and the orientation of the UZP 3 is maintained along the angle, since the groove 32 is made in the same plane as the groove 30 in the protective plug 13. The guide bars 29 are made of steel subjected to special heat treatment, providing the hardness of the linings over 57HRC, which guarantees smooth sliding of the protective plug 13 and the casing 20 of the UZP 3 over them, both in the gaseous medium and in the coolant medium, which is confirmed by the operating experience of the BN-350, BN-600 and BN-800 reactors.

The lowering of the USP 3 occurs in steps, with its heating to the sodium temperature in the reactor (250°C). The heating rate from 1 to 1.3°C/min is controlled by a temperature control sensor 33 (thermal resistance) installed in the housing 20 of the SPD 3. Such a lowering mode is necessary to maintain the operability of the SPD 3 for a long time.

After UZP 3 is heated to a predetermined temperature (250°С), lowering is performed at a constant speed. When approaching the lower position, according to the signal generated by the control system, braking begins. The lowering is carried out until the stop of the body 20 of the UZP 3 in the surfacing 34 on the caisson 35 of the pipe 36 of the reactor. On a signal from the sensor 9 of the tension of the rope 10, the motor 37 of the drive 6 of the vertical movement of the UZP 3 is turned off. Further, the lower case 20 of the UZP 3 is lifted by a manual drive by the number of revolutions, which is determined during commissioning. While the working surface 37 USP 3 is located opposite the window 38 in the pipe 36 of the reactor.

The angular movement of the ultrasonic transducer 3 is carried out when it is in the lower working position using the guide pipe 4. The guide bars 31 on the pipe 4 ensure the rotation of the USP 3 together with the pipe 4, and due to the backlash-free connection of the guide bars 31 with the groove 32 by the body 20, the angle of rotation of the body 20 UZP 3 is equal to the angle of rotation of the guide tube 4. The specified angle of rotation of the guide tube 4 is provided by the drive 5 with an accuracy sufficient to determine the coordinates of a foreign object. Rotation is carried out at a constant speed. When turning the USP 3, the space above the heads of the core assemblies is scanned.

To improve the reliability of operation, the angle of rotation of the guide pipe 4 can be limited. To do this, a stop 40 is installed in the housing 39 of the rotation drive 5, and a sector 41 is installed on the guide pipe 4, the dimensions of which determine the maximum angle of rotation of the pipe 4.

To prevent contact of cable 42 from USP 3 and cable 43 from temperature control sensor 33 of the ultrasonic transducer (thermal resistance) with sodium, they are located in a blind pipe 19, the upper end of which is above the coolant level in the reactor when USP 3 is in the lower extreme position.

To prevent twisting of the rope 10 during the rotation of the UZP 3, its fastening to the pipe 19 is carried out through a rotary device 21, which, by means of a set of balls 44 through an annular conical groove 45, is connected to the upper body 17 through an adjusting gasket 46 and a flange 47. This design guarantees the possibility of turning the rotary device 21 relative to the body 17, and the roller bearings 18 of the rolling exclude swinging during the vertical movement of the rod 11.

The connection of cables 42 and 43 with an external sealed connector 48 is carried out using a flexible tape-chain cable guide 49, which is also connected to the upper housing 17 through a rotary device 21 and ensures the tightness of the internal cavity 50 of the sealed housing 12 of the manipulator. To exclude non-design movement of the tape-chain cable guide 49, a guide channel 51 is made in a sealed housing 12. The wires from the force control device 9 (included in the device) are connected to the control system through an external sealed connector 52.

After scanning the space above the heads of the core assemblies, USP 3 rises to an intermediate position, when the connection of housing 20 of USP 3 and plug 13 is against window 26 in housing 15. Plug 13 is fixed in housing 15 of the lower gate with 8 screws 14. After that, the housing 20 UZP 3 is disconnected from the protective plug 13 and rises to the highest position. The upper and lower gates 7 and 8 are closed. The closure of the upper gate 7 is due to the exclusion of the ingress of radioactive sodium oxides into the central hall during the transportation of the upper part of the manipulator to the washing shaft.

The upper part of the manipulator, above the plane of connector A, is purged with pure argon, filled with air, dismantled and installed on the washing shaft of long equipment for cleaning. A plug from the set of tools and accessories (not shown in the drawings) is installed on the connector plane A of the lower gate 8. After washing, the upper part of the manipulator is transferred to the stand, where it is carried out, revision and, if necessary, replacement of the ultrasonic ultrasonic device with a new one from the set of spare parts and, if necessary, repair.

The proposed manipulator provides an increase in the accuracy of the angular position of the ultrasonic beam and the height position of the ultrasonic transducer. The consequence of this is an improvement in determining the coordinates of a foreign object above the reactor core.

In addition, its advantages are increased reliability, safety and maintainability.

Claims (8)

1. A manipulator for moving an ultrasonic transducer in a fast neutron reactor with a liquid metal coolant, containing a fixed housing made in the form of a pipe with an internal cavity, an ultrasonic transducer placed in it with a rope drive of vertical movement and a device with a drive for angular displacement of the housing, characterized in that that a rotary guide tube is located inside the fixed body, in which a protective plug is permanently installed with the possibility of engaging it during operation with the ultrasonic transducer and moving together with it, the ultrasonic transducer is connected to the guide tube constantly throughout the entire vertical stroke of the ultrasonic transducer, and the ultrasonic transducer is connected using a sealed connector and a tape-chain cable guide. 2. The manipulator according to claim 1, characterized in that to cut off the internal cavity of the manipulator from the cavity of the reactor, it is equipped with gates with drives, and to replace the medium in the internal cavity of the manipulator, it is equipped with valves. 3. Manipulator according to claim. 1 or 2, characterized in that it is equipped with devices for tension and constant control of the tension of the drive rope. 4. The manipulator according to any one of paragraphs. 1-3, characterized in that the ultrasonic transducer is equipped with a temperature control sensor. 5. The manipulator according to any one of paragraphs. 1-4, characterized in that the protective plug in the upper position and during its vertical movement is engaged with the guide tube and is a guide for the ultrasonic transducer. 6. The manipulator according to any one of paragraphs. 1-5, characterized in that the ultrasonic transducer has a rotation device relative to the drive cable and tape-cable guide. 7. The manipulator according to any one of paragraphs. 1-6, characterized in that the cable of the ultrasonic transducer and the cable of the temperature control sensor of the ultrasonic transducer are located in a blind pipe, the upper end of which is above the level of the coolant in the reactor when the ultrasonic transducer is in the lower extreme position, which excludes contact of the liquid coolant with power cables and management. 8. The manipulator according to any one of paragraphs. 1-7, characterized in that the angle of rotation of the guide pipe is limited within the specified limits.

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