KR100287327B1 - Control rod driving device using linear pulse motor - Google Patents

Abstract

The present invention relates to a device for driving a control rod of a nuclear reactor using a linear pulse motor, and to control fine reactivity in an integrated reactor that does not use boric acid for heating the coolant using nuclear fission reaction heat during reactor start-up and controlling the reactivity during operation. It was developed as a control rod driving device. The control rod drive device of the present invention is excellent in fine tuning performance compared to the conventional drive device by using a linear pulse motor, and is driven only by the force of the electromagnetic force, so that the structure is very simple and excellent in reliability by removing the mechanical power transmission mechanism. Do. Control rod drive device of the present invention is composed of a linear pulse motor, position indicator, locking device, shock absorbing device, pressure vessel and the like.

The linear pulse motor is a cylindrical four-phase DC motor that does not require sealing. It adopts a double stator that wraps the mover inside and out to maximize thrust per unit volume. The stator and the cylinder are divided into two types of magnetic and nonmagnetic materials. Welded with metal to form a gyro. By excitation to two neighboring merchant windings of the four merchant windings, the mover is driven up and down, and thus the control rod connected to the mover is transferred up and down. In case of emergency, by turning off the power supply to the linear pulse motor winding line, the mover, which was kept at the designated position by the electromagnetic force, descends rapidly to its own weight and inserts the control rod into the core.

Description

Control Element Drive Mechanism Driven by Linear Pulse Motor

The present invention relates to a control rod driving apparatus using a linear pulse motor, and more particularly, to control fine reactivity in an integrated reactor that does not use boric acid for heating the coolant using nuclear fission reaction heat at the start of the reactor and controlling the reactivity during operation. Developed as a control rod drive system. The control rod drive device of the present invention is excellent in fine tuning performance compared to the conventional drive device by using a linear pulse motor, and is driven only by the force of the electromagnetic force, so that the structure is very simple and excellent in reliability by removing the mechanical power transmission mechanism. Do. Control rod drive device of the present invention is composed of a linear pulse motor, position indicator, locking device, shock absorbing device, pressure vessel and the like.

As a prior art, Korea is currently operating six PWRs from the Westinghouse, two PWRs from Pramatom, and two PWRs from ABB-CE, USA, and two CANDU reactors from Canada. There is. The research reactor is currently in operation at Hanaro, which was built at General Atomic's TRIGA reactor and the Korea Atomic Energy Research Institute. The control rod driving devices used in these reactors have different structures and driving principles for each reactor type, and since they are all introduced from abroad, there are no domestic developments. Pneumatic piston and motor driven lead screw method and rack and pinion in research reactors of TRIGA Mark-II which started in March 1962 and TRIGA Mark-III which started in April 1972. Control rod drive system was used. Pressurized water-type reactors, which have been introduced since 1974, are equipped with magnetic jack-type control rod drives, and CANDU reactors are wire drum-driven. Therefore, there is no control rod drive device using a linear pulse motor as in the present invention.

In foreign countries, the control rod drive began to be used in December 1942 when the first reactor was operated in the United States by Emrico Fermi. Early control rod drive devices are mainly applied to pneumatic driving method, and there is a problem in reliability of piston part. Since the early 1950s, it has been developed as a wire drum method using gears. come. Recently, many advanced reactor developed countries have been developing and using a unique type of control rod drive device according to the characteristics of each reactor. However, the control rod drive device using the linear pulse motor has not been found yet.

The present invention has been developed as a control rod driving device for mounting in an integral reactor that requires a fine reactivity to enable coolant heating using nuclear fission reaction heat during the operation of boric acid-free operation and reactor start-up.

Control rod drive device (1) is usually installed in the upper cover (27) of the reactor (3), the control rod (4) and the extension rod (2) for controlling the core (5) of the reactor for carrying out the above problems. It is a device connected through), and controls the nuclear reactivity of the core by adjusting the insertion amount of control rod when the reactor is in normal operation, and also controls the rod quickly and quickly when an emergency output stop is required due to an accident in the reactor system. It is a device that stops nuclear reactivity by inserting it correctly inside the core.

Control rod drive device of the present invention was developed for the purpose of adjusting the position of the control rod to the integral reactor. In the case of integral reactors where boric acid free operation is the main design requirement, core reactivity should be controlled by control rod alone, so fine adjustment and emergency insertion function should be excellent and reliable control rod drive system should be used. Characteristic of the control rod drive device of the present invention is excellent fine tuning performance by adopting the linear pulse motor 17, the moving part is supported only by the force of the electromagnetic force, so that in the event of an accident, it is possible to quickly insert emergency power only by turning off the power, such as gear or ball bearing power transmission It is very simple and reliable control rod driving device compared to the existing control rod driving device by removing the parts.

1 is a functional explanatory diagram of a control rod drive device.

2 is a structural diagram of a control rod drive device of the present invention.

3 is a longitudinal sectional view of a linear pulse motor adopted in the present invention.

4 is a cross-sectional view of the linear pulse motor adopted in the present invention.

5 is an embodiment of a control rod drive device of the present invention.

<Explanation of symbols for main parts of drawing>

1: control rod driving device 2: extension rod

3: reactor 4: control rod

5: core 6: position indicator

7: position indicating sensor 8: position indicating permanent magnet

9: friction bearing 10: upper pressure vessel

11: sensor container for position indicator

12: shock absorbing spring (in the embodiment, a hydraulic damper is used)

13: lug for locking device 14: locking device

15: locking jaw 16: lower pressure vessel

17: linear pulse motor 18: winding

19: winding core 20: winding block container

21: friction bearing 22: external stator teeth

23: mover 24: internal stator

25 stud bolt 26 control rod drive device fixing flange

27 Reactor vessel head 28 Inner stator mounting tube

29: control rod fixing plate

30: horizontal nonmagnetic material area

31: longitudinal nonmagnetic region 32: magnetic field direction

The linear pulse motor 17 uses a cylindrical four-phase DC synchronous motor and uses a canned motor type that does not require a separate sealing. As shown in FIGS. 3 and 4, the linear pulse motor 17 is connected to the extension rod 2 to move up and down 23 and the inner and outer stator teeth 24 and 22. And it consists of four winding blocks linearly arranged in the up and down driving direction outside the pressure vessel (16). All driving parts, including the mover 23, extension rods 2 and control rods 4 groups, are supported only by the electromagnetic force of the linear pulse motor 17. The stator is separated into an internal stator 24 and an external stator 22 In the meantime, the mover 23 is to move up and down. In order to prevent direct contact between the mover 23 and the stator 24, friction bearings 21 were installed between the structures of each external stator tooth 22 and between the internal stator 24, and the mover 23. Is in contact only with this friction bearing 21. The friction bearing 21 has excellent abrasion resistance even at high temperatures and uses a graphite-fluoroplast having a low coefficient of friction to minimize frictional resistance.

The linear pulse motor 17 adopted in the present invention drives the mover 23 up and down by excitation (two-phase excitation) to two of the four winding wires, as shown in FIG. 3. If the line is 1, 2, 3, 4 in order from the top, then 1-2. The control rod (4) is inserted when it is excited in the order of 2-3, 3-4, 4-1, and the control rod (4) is pulled out when it is excited in the order of 4-3, 3-2, 2-1, 1-4. do. The insertion and withdrawal speed of the control rod 4 is determined by the number of pulses sent from the control device to the linear pulse motor 17. When the pitch of the mover 23 and the stator 24 is p, the mover 23 is designed to be shifted by p / 4 every time the phase changes from the value of the stator 24 (see FIG. 3). 23 moves by one pitch for every four pulses, so that the moving distance (control rod moving distance) of the mover 23 per pulse becomes p / 4. Therefore, the movement distance per pulse can be adjusted by adjusting the tooth pitch of the mover 23 and the stator 24. The windings in each winding may have a number of ways. In the case of four windings arranged at intervals of 90 ° as shown in FIG. 4, the direction of the magnetic lines of force is the direction of the lines of magnetic force 32 of FIG. 4. In order to smooth the direction of the magnetic lines of force 32, certain portions of the pressure vessel 16, the external stator teeth 22 structure, and the mover 23 are made of non-magnetic material as shown in the longitudinal nonmagnetic region 31. Manufacture by welding. Since the winding has a weak resistance to temperature, the winding block is installed outside the pressure vessel 16 so that the primary water does not come in direct contact. The space in which the winding block is installed is made of a thin stainless steel container so as not to contact external air. )

In safe operation, the reactor operator should know the position of the control rod 4 at any time in any case. In the present invention, the permanent magnet 8 is installed on the upper part of the movable member 23 to detect the position of the control rod 4. The up and down movement of the permanent magnet 8 can be detected by the sensor 7 installed outside the upper pressure vessel 10. The position sensing function can be adjusted by adjusting the distance between the sensors 7, but when it is necessary to know a finer position, it can be measured by recording the number of pulses sent from the controller to the linear pulse motor 17. The control rod drive should have a device that can check whether the control rod 4 is fully drawn out (upper limit) and fully inserted (lower limit). The upper two and lower two sensors of the position indicating sensor 7 are the control rod 4 It can act as an upper limit switch and a lower limit switch to detect full insertion and withdrawal of the

In order to prevent the control rod 4 from being drawn out arbitrarily when the reactor is in the safe stop state, a locking device 14 is provided. The locking device 14 is installed on the outer wall of the pressure vessel 16 and designed to be unlocked only when a current is supplied, and the locking device 14 may be installed at the top of the lower container 16 or the bottom of the upper container 10. In other words, when the current is not supplied, as shown in FIG. 2, the locking jaw 15 is caught by the locking lug 13, and withdrawal is prevented, whereas when the control rod 4 is withdrawn, the locking devices 13 and 14 are required. , 15) to release the lock by moving the locking lug inward.

In addition, when the external power is cut off during an emergency, the moving part which is maintained only by the electromagnetic force generated in the pulse motor is rapidly inserted into the own weight of the group of the mover 23, the extension rod 2 and the control rod 4, and the like. At this time, in order to prevent damage to the control rod drive device due to the impact dropping is installed a hydraulic damper or shock absorbing spring 12 in the lower portion of the upper container (10).

EXAMPLE

As shown in FIG. 2, the control rod drive device of the present invention includes a position indicator 6, a linear pulse motor 17, a locking device 14, an impact absorbing device 12, and the like. The main parts of the position indicator 6 are a permanent magnet 8 and a sensor 7 for detecting the movement of the permanent magnet 8. Permanent magnet (8) is mounted on the upper portion of the linear pulse motor 17, the movable member (23) and the position sensor (7) is arranged at regular intervals up and down outside the upper pressure vessel (10). The linear pulse motor 17 is a canned motor type, which is connected to the extension rod 2 and moves up and down, the inner and outer stator teeth 24 and 22, and the pressure vessel 10 and 16. It consists of four upper windings arranged linearly in the up and down driving direction on the outside. The linear pulse motor 17 is installed inside and outside the lower pressure vessel 16, and the lower pressure vessel 16 is connected to the upper pressure vessel 10 in which the position indicator 6 is installed. The locking device 14 is installed at the lower side of the upper pressure vessel 10 or the upper outer wall of the lower pressure vessel 16. The upper pressure vessel 10 and the lower pressure vessel 16 are connected by stud bolts and nuts, and are sealed by a gasket made of copper having a square cross section. The control rod drive system is secured with stud bolts 25 and nuts on the reactor head using a fixing flange 26 and uses a rectangular copper gasket for sealing.

[Variation of the invention, application example]

By changing the sizes of the internal stator 24 and the external stator 22 tooth structure, the distance the control rod 4 moves per pulse can be adjusted. In addition, since the structure is very simple and the emergency insertion function is excellent, it is very easy to change the design to the control rod driving device used exclusively for emergency insertion.

The control rod drive device of the present invention is simple in design and easy to change according to the weight of the drive portion. Looking at the damage mechanism of the conventional control rod drive device, there are many damages in the power transmission mechanical parts driven by two parts such as extension rods and latch grippers, and the control rod drive device of the present invention uses these parts at all. It is not only very reliable but also easy to maintain. Therefore, the control rod drive device of the present invention is a drive device suitable for an integrated nuclear reactor is required that the fine adjustment function of the control rod, excellent emergency insertion function, high reliability and the like.

Claims (4)

In the control rod drive device of the integrated reactor provided so that the control rod drive device (1), the extension rod (2), the control rod (4) is elevated to the core (5) relative to the reactor (3), for the position sensing of the control rod (4) Position indicator (6) to detect the up and down operation of the permanent magnet (8) by the position sensor (7) on the outside of the upper pressure vessel (10) in which the shock absorbing spring 12 is installed on the upper and inner sides of the mover (23). ) And driving parts such as the movable member 23, the extension rod 2, and the control rod 4, which are installed between the inner and outer stators 24 and 22, are supported by the electromagnetic force of the linear pulse motor 17, and the control rod ( 4) A linear pulse, characterized in that the locking device 14 is provided with the locking jaw 15 and the locking lug 13 of the movable member 23 on the upper outer side of the lower pressure vessel 16 in order to control the withdrawal. Control rod driving device using motor. The structure of claim 1, wherein the stator wraps the mover 23 in and out by separating the stator into the inner stator 24 and the outer stator 22 in order to maximize the thrust per unit volume of the linear pulse motor 17. Control rod drive device using a linear pulse motor, characterized in that the. The method of claim 1, wherein the four sides of the pressure vessel 16, the external stator teeth 22 structure, and the movable member 23 are welded 31 with a non-magnetic material in the longitudinal direction to guide the direction of the lines of magnetic force. Control rod drive device using linear pulse motor. The friction bearing made of Graphite Fluoroplast material according to claim 1, wherein the friction bearing is excellent in wear resistance and has a low friction system between the internal stator teeth 22 structure and the external stator teeth 24 structure in order to prevent contact between the mover and the stator. Control rod drive device using a linear pulse motor, characterized in that 21 is installed.