KR20000025702A - Control stick driving apparatus - Google Patents

Abstract

PURPOSE: A control stick driving apparatus is provided to improve a reliability and to be easy to maintain and mend by eliminating a latch gripper. CONSTITUTION: A control stick driving apparatus of a monolithic atomic pile is installed such that a control stick(4) goes up and down with regard to a reactor core(5). The control stick driving apparatus comprises a place director(6), a permanent magnet(8) composing an important part of the place director(6), a sensor(8) for sensing a movement of the permanent magnet(8), a linear pulse motor(17) installed inside and outside a lower pressure container(16), a lock apparatus(14) and an impact absorption apparatus(12).

Description

Control rod driving device using 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 during reactor start 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. In research reactors of the TRIGA Mark-II, which started in March 1962 and the TRIGA Mark-III, which started in April 1972, the pneunntic piston and motor driven lead screw method and rack and piny The control rod driving device of the on type 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 Enrico 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 conceptual diagram of a control rod drive device of the present invention

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

4 is a cross-sectional view of a 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 the main parts of the drawings

(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 bearings (10): Upper pressure vessel

(11): sensor container for position indicator

(12): Shock-absorbing spring (hydraulic damper in the embodiment)

(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 bearings (22): external stator teeth

(23): mover (24): internal stator

(25): Stud bolt (26): Flange for fixing control rod drive device

(27): Reactor vessel head (28): Tube for installing internal stator

(29): control rod fixing plate

(30): Horizontal nonnnngnetic material area

(31): longitudinal nonmagnetic region 32: magnetic field direction

Linear pulse motor uses cylindrical four-phase DC synchronous motor and canned motor type that does not need separate sealing. As shown in FIGS. 3 and 4, the linear pulse motor is connected to the extension rod 2 to move up and down 23 and the inner and outer stator teeth 22 and 24, and outside the pressure vessel. It consists of four winding blocks arranged linearly in the vertical direction in the side. All driving parts including the mover, extension rod and control rod group are supported by the electromagnetic force of the linear pulse motor only. The stator is separated into the inner stator (24) and the outer stator (18, 19, 22), and the mover moves up and down between them. Too. In order to prevent direct contact between the mover and the stator, a friction bearing 21 is installed between each external stator tooth structure and between the internal stator, and the mover comes into contact only with the friction bearing. This friction bearing material is made of Graphite-fluoroplast, which has excellent wear resistance and low coefficient of friction even at high temperatures, to minimize frictional resistance. The linear pulse motor adopted in the present invention drives the mover up and down by excitation (two-phase excitation) to two of the four winding wires, as shown in FIG. 3. , 3, 4, excitation in the order of 1-2, 2-3, 3-4, 4-1, the control rod is inserted, 4-3, 3-2, 2-1, 1-4 When excited, the control rod is withdrawn. The insertion and withdrawal speed of the control rod is determined by the number of pulses sent from the controller to the linear pulse motor. If the tooth pitch of the mover and stator is p, the mover tooth is designed to be shifted by p / 4 every time the phase changes from the stator tooth (see Fig. 3), so that the mover moves one pitch every four pulses. The moving distance of the mover (control rod moving distance) per pulse is p / 4. Therefore, the movement distance per pulse can be adjusted by adjusting the tooth pitch of the mover and the stator. There may be a variety of ways to arrange the windings in each winding wire. When the winding consists 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. In order to smooth the direction of the magnetic force lines, the pressure vessel, the external stator tooth structure, and a certain portion of the movable part are welded with a nonmagnetic material as shown in the longitudinal nonmagnetic region 31. Since the winding has a weak resistance against temperature, the winding block is installed outside the pressure vessel so that the primary water does not come in direct contact with the winding block. The winding block is covered with a thin stainless steel container 20 so as not to contact external air. .

In safe operation, the reactor operator should know the position of the control rod at any time in any case. In the present invention, in order to detect the position of the control rod, the permanent magnet 8 is installed on the upper part of the mover and the upper and lower movements of the permanent magnet are applied to the upper pressure. The sensor 7 installed outside the container 10 can be detected. The position sensing function can be adjusted by adjusting the distance between the sensors. If it is necessary to know the finer position, it can be measured by recording the number of pulses sent from the controller to the linear pulse motor. The control rod driving device should be equipped with a device to check whether the control rod is fully pulled out (upper limit) and fully inserted (lower limit). The upper two and lower two sensors of the position indicating sensor detect the complete insertion and complete withdrawal of the control rod. It can serve as the upper limit switch and the lower limit switch.

Locks 13, 14, and 15 are installed to prevent the control rods from being drawn out when the reactor is in a safe stop state. The locking device is installed on the outer wall of the pressure vessel and designed to be unlocked only when the current is supplied, and it can be installed on the top of the lower vessel or the bottom of the upper vessel. That is, in the case where no current is supplied, as shown in FIG. 2, the locking jaw 15 is caught by the locking lug 13 and the withdrawal is prevented, whereas when the control rod is withdrawn, the locking lug is supplied by supplying the current to the locking device. To move it inward to unlock it. In addition, when the external power is cut off during an emergency, the moving part, which is maintained only by the electromagnetic force generated from the pulse motor, is rapidly inserted into the own weight of the mover, the extension rod, and the control rod group. At this time, a hydraulic damper or a spring is installed at the lower part of the upper container to prevent damage to the control rod driving device due to the falling impact.

Example

As shown in Figure 2, the control rod drive device of the present invention is composed of a position indicator, a linear pulse motor, a locking device, a shock absorbing device. The main parts of the position indicator are the permanent magnet 8 and the sensor 7 for detecting the movement of the permanent magnet. The permanent magnet is mounted on the upper part of the linear pulse motor mover, and the position sensor is disposed at a predetermined interval up and down outside the upper pressure vessel 10. The linear pulse motor is a canned motor type, which is connected to the extension rod 2 and moves up and down 23 and the inner and outer stator teeth, and four upper windings linearly arranged in the vertical direction outside the pressure vessel. Consists of The linear pulse motor is installed inside and outside the lower pressure vessel 16, and the lower pressure vessel is connected to the upper pressure vessel in which the position indicator is installed. The locking device 14 is installed at the lower side of the upper pressure vessel or the outer wall of the lower pressure vessel. The upper and lower pressure vessels are connected by stud bolts and nuts and are sealed by a gas jet made of copper with a square cross section. The control rod drive system is secured with a stud bolt 25 and a nut on the reactor head using a fixing flange 26 and uses a rectangular copper gasket for sealing.

Modifications of the Invention, Application Examples

By changing the size of the internal stator and external stator teeth, the distance the control rod moves per pulse can be controlled. 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, such as fine adjustment function, excellent emergency insertion function, high reliability of the control rod.

Claims (6)

4. A control rod drive device using a linear pulse motor, characterized in that the reactor control rod drive device is installed to be driven by a four-phase direct current linear pulse motor of a canned motor type that does not require a separate seal. In the control rod drive of the integrated reactor, in which the control rod driving device (1), the extension rod (2), and the control rod (4) are elevated on the core (5) with respect to the reactor (3), the control rod driving device is a position indicator (6). , A linear pulse composed of a stator, a mover, and a winding, which is installed inside and outside of the permanent magnet (8) and the sensor (8) for detecting the movement of the permanent magnet (8) and the lower pressure vessel (16) as a main component of this position indicator. Control rod drive device using a linear pulse motor, characterized in that composed of a motor (17), a locking device (14), a shock absorbing device (12). The method of claim 2, In order to maximize the thrust per unit volume of the linear pulse motor 17, the stator is separated into the inner stator 24 and the outer stator 22 so that the stator has a structure in which the stator surrounds the mover 23 in and out. Control rod driving device using pulse motor. The method of claim 2, The control rod driving device using the linear pulse motor, characterized in that the emergency insertion reliability is improved by supporting all moving parts including the mover 23 without any mechanical support structure such as latch gripper. . The method of claim 2, Control vessel using a linear pulse motor, characterized in that the magnetic stator direction is induced by welding (31) the four edges of the pressure vessel (16) external stator tooth (22) structure and the mover (23) with a non-magnetic material in the longitudinal direction. Drive system. The method of claim 2, In order to prevent the mover and the stator from contacting each other, between the internal stator teeth 22 structures and the external stator teeth 24 structures, a friction bearing 21 made of Graphite Fluoroplast material having excellent abrasion resistance and low friction system at high temperatures is installed. Control rod drive device using a linear pulse motor, characterized in that.