JPH1010264A - Control rod drive mechanism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance the reliability of a plant by detecting the rotational position of an inner rotor and comparing the detected rotational position with that of an outer rotor thereby making possible to detect the slip of a magnet coupling. SOLUTION: Since the distance between a displacement measuring unit 201 and the side face of a rotary member 200 varies periodically due to the rotation of an inner rotor 67, an output synchronized with the rotation is obtained from the displacement measuring unit 201. Consequently, a signal processing system 202 can determine the rotational angle of an inner rotor 67 and the rotational speed thereof. On the other hand, the rotational position of an outer rotor 64 can be measured through a rotational position detector 203 which delivers an output to the signal processing system 202. The signal processing system 202 is an output processing means for comparing the output from the rotational position detector 203 with the output from the displacement measuring unit 201 and it can compare the rotational angle, rotational speed, and the like between the inner rotor 67 and the outer rotor 64. Consequently, generation of a slip in the magnet coupling can be detected using the displacement measuring unit 201, the rotational position detector 203 and the signal processing system 202.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control rod drive mechanism (hereinafter referred to as "CRD") used in a boiling water reactor (hereinafter referred to as "BWR").

[0002]

2. Description of the Related Art FIG. 13 is a schematic diagram showing a general BWR. As shown in the drawing, a coolant 2 also serving as a moderator is accommodated in a reactor pressure vessel 1, while a core 3 is arranged at a lower center portion of the reactor pressure vessel 1 and is surrounded by a core shroud 4. ing. A large number of fuel assemblies (not shown) are loaded in the core 3, and control rods 5 are removably accommodated between a set of four fuel assemblies.

[0003] In this BWR, the coolant 2 flows upward in the core 3, during which heat generated by the nuclear fission chain reaction from the core 3 is transmitted to the coolant 2, and the coolant 2 is heated and heated. The cooled coolant 2 travels above the reactor core 3 as a gas-liquid two-phase flow of water and steam, and is guided from the reactor core 3 to the steam separator 6.

[0004] The gas-liquid two-phase flow coolant is separated into water and steam by the steam separator 6, and then the steam is dried by a steam dryer (not shown).
Through the main steam pipe to the steam turbine system to drive the steam turbine. The steam that worked in the steam turbine system is condensed in the condenser and condensed.
The water is returned to the reactor pressure vessel 1 via a water supply system (not shown) as water supply again.

On the other hand, the water separated by the steam separator 6 flows down the downcomer section 7 and is guided to the lower part of the reactor core 3 in a state where it is mixed with the water supplied through the reactor condensing / water supply system.
It is led to the core 3 again.

A control rod 5 is moved into and out of the core 3 of the reactor pressure vessel 1 by a control rod drive mechanism 8 for starting / stopping the reactor and adjusting the reactor power. The control rod driving mechanism 8 extends downward from the bottom 1 a of the reactor pressure vessel 1.
An integrated structure housed in the RD housing 9;
It is fixed to the lower flange 9a of the RD housing 9 by bolting.

The control rod drive mechanism 8 is an electric drive type control rod drive mechanism as shown in FIG.
The rotation shaft 11 of the electric motor 10 is connected to the drive shaft 13 of the control rod drive mechanism 8 via the gear coupling mechanism 12. The drive shaft 13 is a ball screw shaft 1
The ball nut 15 is screwed to the ball screw shaft 14.

A pair of rollers 16 is mounted on the ball nut 15 so as to sandwich an axial mounting plate 18 formed on the inner peripheral surface of a guide tube 17.
Above the ball nut 15, a hollow piston 19 is provided.
The hollow piston 19 is connected to the control rod 5 via a coupling 20 attached to the upper end.
Further, an electromagnetic brake 21 is attached to the electric motor 10, and the electric motor 10 is stopped by operating the electromagnetic brake 21. A synchro position detector 22 is provided at the lower end of the electromagnetic brake 21, and the position of the control rod 5 is detected by the synchro position detector 22.

A motor bracket 23 is disposed above the electric motor 10 and around the gear coupling mechanism 12, and a spool piece 24 as a partition wall for primary cooling water is fixed on the motor bracket 23. Have been. The drive shaft 13 passes through the spool piece 24, and a gland packing 25 is used as a seal member for the drive shaft 13. In other stationary seal portions, rubber O-rings 26 and 27 are used.

In the control rod driving mechanism 8 configured as described above, when the electric motor 10 is rotationally driven, the ball screw shaft 14 is rotated via the rotating shaft 11 and the driving shaft 13, and the rotation of the ball screw shaft 14 is performed. As a result, the ball nut 15 moves up and down. At this time, the rotation of the ball nut 15 is restricted by the mounting plate 18 via the roller 16 and moves up and down. The control rod 5 moves up and down via the hollow piston 19 by the up and down movement of the ball nut 15. The vertical movement of the control rod 5 adjusts the amount of insertion and withdrawal from the core 3 and limits the furnace power.

Next, a case where an emergency situation occurs in the BWR to scram the reactor will be described. That is,
During a reactor scram, high-pressure driving water is supplied from the scram insertion pipe 33 connected to the lower flange 9 a of the CRD housing 9 to the lower surface side of the hollow piston 19 via the injection port 34. By supplying the high-pressure driving water, the hollow piston 19 installed on the ball nut 15 is pushed upward, and the control rod 5 is inserted into the core 3 at a high speed, whereby the reactor is scrammed. Here, the scrum position of the hollow piston 19 is detected by detecting the position of the magnet 150 attached to the hollow piston 19 by the scrum position detector 36 having the reed switch 35.

In the conventional control rod drive mechanism 8 described above, the drive shaft 13 penetrates the spool piece 24 as a partition wall of the primary cooling water, and the gland packing 25 is used as a seal member of the drive shaft 13. . In addition, since a rubber seal is used in the other stationary seal portions, it is impossible to completely seal the primary cooling water, and slight leakage is allowed. In addition, since the gland packing 25 and the rubber O-rings 26 and 27 are made of a nonmetallic material, they deteriorate over time and need to be replaced periodically. Further, as a result, there has been a problem that the maintenance frequency increases.

Therefore, in order to solve this problem, the rotational power of the electric motor 10 is transmitted to the ball screw shaft 14 in a non-contact manner through the pressure bulkhead by the magnetic force of the magnet, and the penetrating portion of the pressure bulkhead becomes unnecessary. Control rod drive mechanism is Japanese Patent Application No. Hei 7-
No. 32557.

The invention described in Japanese Patent Application No. 7-32557 will be described with reference to FIG. The control rod drive mechanism 50 is an electric drive type control rod drive mechanism, and is fixed to the lower flange 9a of the CRD housing 9 disposed to extend downward from the bottom 1a of the reactor pressure vessel 1 by bolting. .

A motor 51 such as a stepping motor is attached to the lower part of the control rod driving mechanism 50. The rotational driving force from the motor 51 is a magnetic coupling 52.
Is transmitted to the drive shaft 53 via the The magnet coupling 52 is disposed below the drive shaft 53, and has an inner magnet 54 as a first magnet on the driven side and a spool piece 56 as a primary cooling water wall outside the inner magnet 54. And an outer magnet 55 as a second magnet on the drive side provided on the motor 51 shaft. Each of the inner magnet 54 and the outer magnet 55 has a structure in which an even number of cylindrical magnets are equally divided vertically, magnetized in the radial direction, and magnetic poles are alternately arranged.

FIG. 16 is a sectional view taken along line AA of FIG. 15, and the structure and principle of the magnet coupling will be briefly described. Note that the motor bracket 57 and the like are omitted to avoid complicating the drawing. FIG. 16 shows an example in which an 8-pole radial type magnetic coupling is used. The magnet is magnetized in the direction of the arrow shown in the figure in a shape obtained by vertically dividing a cylinder, and is attached to the outer yoke 60 and the inner yoke 61 so that the directions of the adjacent magnet and the N pole and the S pole are alternated. ing. The relative rotational positional relationship between the inner rotor 67 and the outer rotor 64 shown in this figure is a stable phase in which the attractive force and the repulsive force of the magnetic poles are balanced. There are four such stable phases in the case of an 8-pole magnetic coupling.

The outer magnet 55 and the inner magnet 5
4, there is a pressure bulkhead 58 provided below the spool piece 56. Inner rotor 67 and outer rotor 6
As shown in FIG. 17, in the case where 4 has an angle shift with respect to the stable phase (hereinafter, this angle is referred to as a shift angle), the attractive force and the repulsive force between the outer magnet 55 and the inner magnet 54 cause A torque is generated to eliminate the deviation and return to the stable phase. The relationship between the torque and the shift angle is generally as shown in the graph of FIG. The deviation angle is 360 ÷ 2
The torque becomes maximum at the number of poles [deg] (22.5 degrees in the case of the 8-pole magnet coupling in the example) (hereinafter referred to as the maximum static torque). In the case of a number [deg] (45 degrees in this example), it becomes 0. This 360 ° pole number [deg] is hereinafter referred to as a slip occurrence angle. At an angle equal to or greater than the slip occurrence angle, a torque acts to advance the deviation angle and approach the adjacent stable phase.

Therefore, the magnet coupling cannot apply a torque larger than the maximum static torque, and when the deviation angle exceeds 45 degrees due to the addition of the torque larger than the maximum static torque,
The inner rotor 67 and the outer rotor 64 relatively rotate to the next stable phase, and do not return to the original stable phase even when the load is removed. This is called slippage of the magnetic coupling. As will be described later, in the case of a control rod drive mechanism to which a magnet coupling is applied, in order to prevent occurrence of slip, it is necessary to design a torque with a sufficient margin for an assumed load torque.

Returning to FIG. 15, the drive shaft 53 is connected to the ball screw shaft 14, and the rotational driving force of the drive shaft 53 is transmitted to the ball screw shaft 14. The hollow piston lifting / lowering mechanism is constituted by the ball screw shaft 14, the ball nut 15, and the roller 16, as in the conventional example shown in FIG.

A motor bracket 57 is arranged above the electric motor 51 and around the magnet coupling 52. And spool piece 56 and CRD
A metal O-ring 66 is used as a seal member between the lower flange 9a of the housing 9 and the metal O-ring 66 prevents primary cooling water from leaking.
Maintenance frequency is lower than that of rubber O-rings.

In the control rod driving mechanism having such a configuration, the driving shaft 53 is rotated via the magnet coupling 52 by the rotational driving of the electric motor 51. In other words, the rotation of the electric motor 51 rotates the outer magnet on the drive side, and the inner magnet 54 on the driven side rotates with this rotation, thereby rotating the drive shaft 53. When the drive shaft 53 rotates, the ball screw shaft 14 is rotated to move the ball nut 15 up and down (up and down). As the ball nut 15 moves up and down, the control rod 5 moves up and down via the hollow piston 19 to adjust the furnace power.

The control rod 5 is held at the insertion position by regulating the rotation of the ball screw shaft 14 by the holding torque of the electric motor 51 itself and the action of the electromagnetic brake.

On the other hand, when scramming the reactor,
This is the same as the conventional example shown in FIG. In the conventional example shown in FIG. 15, a control rod drive mechanism 50 is disposed below a drive shaft 53, and an inner magnet 54 on a driven side, and an electric motor 5 separated by a spool piece 56 outside the inner magnet 54.
By arranging the magnet coupling 52 composed of the outer magnet 55 on the drive side provided on one shaft, the seal portion of the drive shaft 53 is not required. Therefore, since there is no component penetrating the spool piece 56, a shaft sealing member such as a conventional gland packing is not required.

[0024]

In the above-described conventional control rod driving mechanism, when the slippage of the magnet coupling occurs, the position of the control rod detected by the synchro position detector 22 shown in FIG. Differences in rod positions can occur, which can hinder plant operation. As a countermeasure, the magnet coupling is designed to have a sufficient transmission torque exceeding the assumed maximum load torque.However, if a slip occurs, a means to detect it should be provided. Necessary countermeasures, such as shutting down the reactor, can be promptly performed, and the reliability of the plant is further improved. The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a control rod drive mechanism capable of detecting slippage of a magnetic coupling.

[0025]

According to a first aspect of the present invention, there is provided a control rod driving mechanism provided in a housing extending below a reactor and comprising a motor. Is transmitted to the hollow piston elevating mechanism via the drive shaft to raise and lower the hollow piston, and a control rod drive mechanism of a reactor power that inserts and withdraws a control rod engaged with the hollow piston into the reactor core. A spool piece provided at the lower end of the housing to seal primary cooling water inside the reactor, an outer yoke connected to a rotating shaft of the electric motor provided at an outer lower portion of the spool piece, and an outer yoke. An outer magnet provided,
It has an inner yoke provided on the drive shaft provided inside the spool piece and connected to the hollow piston elevating mechanism, an inner magnet provided on the inner yoke, and a rotation detecting means for the inner magnet. .

Further, the control rod driving mechanism according to the second aspect of the present invention,
2. The control rod drive mechanism according to claim 1, wherein the rotation detecting means is provided on a drive shaft provided on the drive shaft which rotates together with the inner magnet, and has a surface formed with irregularities, and is provided opposite to a rotation horizontal plane of the rotation member. And a displacement detector for measuring a distance from irregularities formed on a side surface of the rotating member.

A control rod driving mechanism according to a third aspect of the present invention is the control rod driving mechanism according to the first aspect, wherein the rotation position detecting means detects the output from the rotation detecting means of the inner magnet and the rotation of the rotating shaft of the electric motor. And an output processing means for comparing the output of

According to the configuration of the control rod drive mechanism according to any one of claims 1 to 3, slippage of these magnets can be detected by comparing the rotational position of the inner magnet with the rotational position of the outer magnet.

According to a fourth aspect of the present invention, there is provided a control rod driving mechanism for detecting the vertical position of the control rod by the insertion and withdrawal of the control rod in place of the inner magnet rotation detecting means in the control rod driving mechanism of the third aspect. It has.

According to such a configuration, slippage between the inner magnet and the outer magnet can be detected. The control rod drive mechanism according to claim 5 is provided in a housing extending below the reactor, and transmits the rotation of the electric motor to a hollow piston elevating mechanism via a drive shaft to raise and lower the hollow piston. Insert the control rod that engages the piston into the reactor core
In the control rod drive mechanism of the reactor power to be pulled out, the spool piece is provided at the lower end of the housing and seals the primary cooling water inside the reactor, and is connected to a rotating shaft of the electric motor provided at an outer lower portion of the spool piece. An outer yoke, an outer magnet provided on the outer yoke, an inner yoke provided on the drive shaft provided inside the spool piece and connected to the hollow piston lifting / lowering mechanism, and provided on the inner yoke. And a means for detecting the phase difference between the current and the voltage of the electric motor and estimating the torque of the electric motor.

A control rod driving mechanism according to a sixth aspect of the present invention is provided in a housing extending below the reactor, and transmits the rotation of the electric motor to a hollow piston elevating mechanism via a driving shaft to raise and lower the hollow piston. In a control rod drive mechanism of a reactor output, which inserts and withdraws a control rod engaged with the hollow piston into a reactor core, a spool piece provided at a lower end portion of the housing to seal primary cooling water inside the reactor. And an outer yoke connected to a rotating shaft of the electric motor provided at an outer lower portion of the spool piece, an outer magnet provided at the outer yoke, and connected to the hollow piston elevating mechanism provided inside the spool piece. An inner yoke provided on the drive shaft, an inner magnet provided on the inner yoke, and a frequency of a current waveform of the electric motor. And it has a analysis means.

A control rod driving mechanism according to a seventh aspect of the present invention has a frequency analysis means for a voltage waveform instead of the frequency analysis means for a current waveform of a motor in the control rod driving mechanism according to the sixth invention.

The control rod driving mechanism according to the present invention is provided in a housing extending below the reactor, and transmits the rotation of the electric motor to the hollow piston elevating mechanism via the driving shaft to raise and lower the hollow piston. In a control rod drive mechanism of a reactor output, which inserts and withdraws a control rod engaged with the hollow piston into a reactor core, a spool piece provided at a lower end portion of the housing to seal primary cooling water inside the reactor. And an outer yoke connected to a rotating shaft of the electric motor provided at an outer lower portion of the spool piece, an outer magnet provided at the outer yoke, and connected to the hollow piston elevating mechanism provided inside the spool piece. An inner yoke provided on the drive shaft, an inner magnet provided on the inner yoke, and a load torque detecting means for the electric motor. Has, the motor is an induction motor, the load torque detection means detects a load torque from the rotational speed of the motor.

According to the configuration of the control rod drive mechanism according to the fifth to eighth aspects, by detecting the torque applied to the electric motor, it is possible to detect a change in the torque generated due to the slip.

The control rod driving mechanism according to the ninth aspect is provided in a housing extending below the reactor, and transmits the rotation of the electric motor to the hollow piston elevating mechanism via the driving shaft to raise and lower the hollow piston. In a control rod drive mechanism of a reactor output, which inserts and withdraws a control rod engaged with the hollow piston into a reactor core, a spool piece provided at a lower end portion of the housing to seal primary cooling water inside the reactor. And an outer yoke connected to a rotating shaft of the electric motor provided at an outer lower portion of the spool piece, an outer magnet provided at the outer yoke, and connected to the hollow piston elevating mechanism provided inside the spool piece. An inner yoke provided on the drive shaft, an inner magnet provided on the inner yoke, and a torsion applied to a rotating shaft of the electric motor. And has a torque detecting means for detecting a torque applied to the concatenated drive shaft click or motor.

According to a tenth aspect of the present invention, in the control rod driving mechanism according to the ninth aspect, a slip detecting means for detecting a slip generated between the outer magnet and the inner magnet using the detected torque. Have

According to the configuration of the control rod driving mechanism according to the ninth and tenth aspects, the slip can be detected by detecting a change in torque caused by the slip. The control rod drive mechanism according to claim 11 is provided in a housing extending below the reactor, and transmits the rotation of the electric motor to a hollow piston elevating mechanism via a drive shaft to raise and lower the hollow piston. Insert the control rod that engages the piston into the reactor core
In the control rod drive mechanism of the reactor power to be pulled out, the spool piece is provided at the lower end of the housing and seals the primary cooling water inside the reactor, and is connected to a rotating shaft of the electric motor provided at an outer lower portion of the spool piece. An outer yoke, an outer magnet provided on the outer yoke, an inner yoke provided on the drive shaft provided inside the spool piece and connected to the hollow piston lifting / lowering mechanism, and provided on the inner yoke. And a distortion detecting means for detecting distortion generated in a stator of the electric motor or a member fixing the stator to a reactor pressure vessel.

According to a twelfth aspect of the present invention, a control rod driving mechanism according to the eleventh aspect of the present invention replaces the distortion detecting means of the control rod driving mechanism according to the eleventh aspect.
It has a strain detecting means for detecting a strain generated in a brake for restricting the rotation of the rotating shaft or a member for fixing the brake to the reactor pressure vessel.

According to the construction of the control rod drive mechanism of the present invention, the stator of the electric motor or the member for fixing the stator to the reactor pressure vessel, or the brake or the brake for rotatingly restraining the rotating shaft is provided on the reactor pressure vessel. By detecting the distortion generated in the member fixed to the, it is possible to detect a change in torque generated due to the slip.

A control rod drive mechanism according to a thirteenth aspect is provided in a housing extending below the reactor, and transmits the rotation of the electric motor to a hollow piston lifting mechanism via a drive shaft to raise and lower the hollow piston. In a control rod drive mechanism of a reactor output, which inserts and withdraws a control rod engaged with the hollow piston into a reactor core, a spool piece provided at a lower end portion of the housing to seal primary cooling water inside the reactor. And an outer yoke connected to a rotating shaft of the electric motor provided at an outer lower portion of the spool piece, an outer magnet provided at the outer yoke, and connected to the hollow piston elevating mechanism provided inside the spool piece. An inner yoke provided on the drive shaft, an inner magnet provided on the inner yoke, and a stator or Stator and those having an acceleration detecting means for detecting a rotational acceleration generated in a member fixed to the reactor pressure vessel.

According to a fourteenth aspect of the present invention, there is provided a control rod driving mechanism according to the thirteenth aspect, wherein a brake for restraining the rotation of the rotating shaft or a brake is fixed to the reactor pressure vessel instead of the acceleration detecting means. And an acceleration detecting means for detecting a rotational acceleration generated in the motor.

According to the construction of the control rod driving mechanism according to the thirteenth and fourteenth aspects, the stator of the electric motor or the member for fixing the stator to the reactor pressure vessel, or the brake or the brake for rotatingly restraining the rotating shaft is provided in the reactor pressure vessel By detecting the rotational acceleration generated in the member fixed to the vehicle, it is possible to detect a change in torque generated due to the slip.

[0043]

FIG. 1 shows a first embodiment (corresponding to claims 1 to 3) of a control rod driving mechanism according to the present invention.
A description will be given based on (a) and (b). FIG.
FIG. 3A is a sectional view taken along line BB of FIG. FIG. 1 (a),
15B, the same parts as those in FIG. 15 are denoted by the same reference numerals, and the description of the configuration will be omitted. In the present embodiment, in order to detect the rotation of the inner magnet 54 that rotates together with the inner rotor 67, the disk-shaped rotating member 200 is installed on the drive shaft 53 to which the inner rotor 67 is connected.

Since this rotating member is provided in the spool piece 56, it is installed in a pressure boundary which is a pressure barrier of the primary cooling water of the reactor. Irregularities are formed on the surface of the rotating member 200. In the present embodiment, a large number of grooves 22 are periodically formed on the side surface of the rotating member 200.
5 is provided. In addition, on the side surface of the spool piece 56, a displacement measuring device 201 is installed as a rotation detecting means for measuring and outputting a distance from irregularities formed by providing a large number of grooves 225 on the surface of the rotating member 200 as a detection target surface. ing.

As the displacement measuring device 201, a measuring device such as an eddy current displacement meter capable of measuring a distance to a conductor, a laser displacement meter for measuring a distance from a time until a laser beam is irradiated on an object surface and returned, and the like are used. be able to. The output of the displacement measuring device 201 is transmitted to a signal processing system 202 having a function as an electronic counter via a signal line. Since the distance between the displacement measuring device 201 and the side surface of the rotating member 200 changes periodically due to the rotation of the inner rotor 67, an output synchronized with this rotation is obtained from the displacement measuring device 201. The rotation angle of the inner rotor 67 can be determined by counting the period of the output fluctuation using the signal processing system 202. Also, from the transition of the rotation angle with respect to time,
The rotation speed can be determined.

On the other hand, the rotation position of the outer rotor 64 is
The rotation can be measured by a rotation position detector 203 which is a rotation position detection means for detecting the rotation of the shaft of the electric motor 51.
As the rotation position detector 203, for example, a synchro position detection device of a conventional control rod driving device can be used.
The output of the rotational position detector 203 is guided to a signal processing system 202 via a signal line. This signal processing system 20
Reference numeral 2 denotes output processing means for comparing the output of the rotational position detector 203 and the output of the displacement measuring device 201.
And the rotation angle and rotation speed of the outer rotor 64 can be compared.

When no slip occurs in the magnetic coupling, the difference between the rotational position of the inner rotor 67 and the rotational position of the outer rotor 64 is within the slip occurrence angle. Therefore, by using the displacement measuring device 201, the rotational position detector 203, and the signal processing system 202,
The occurrence of slip can be detected.

Next, a second embodiment (corresponding to claim 4) of a control rod driving mechanism according to the present invention will be described with reference to FIG. This embodiment is characterized in that a control rod position detecting device 204 and a signal processing system 205 for comparing the outputs of the control rod position detecting device 204 and the rotational position detector 203 are provided as a control rod vertical position detecting means. is there. The detection of the control rod vertical position can be performed based on the same principle as the scrum position detector 36 of the conventional control rod drive mechanism, for example. In addition, the position of a magnet (not shown) installed on the hollow piston 19 can be detected using a magnetostrictive sensor capable of continuously detecting the position of the magnet using the magnetostriction phenomenon. In the present embodiment, the control rod position detecting device 204 is the CRD housing 9
Although installed outside, the control rod drive mechanism 5 is not limited to this.
0. If there is no slippage in the magnet coupling, there is a slight deviation between the control rod position obtained by the rotation position detection device 203 and the control rod vertical position detected by the control rod position detection device 204 within the slip occurrence angle. I don't care. Therefore, by comparing the two outputs with the signal processing system 205, the occurrence of slip can be detected.

Next, the third control rod driving mechanism according to the present invention will be described.
The embodiment (corresponding to claim 5) will be described with reference to FIG. In the present embodiment, the control rod drive mechanism 50 of FIG.
Since there is no change in the spool piece 56, only the peripheral portion of the electric motor is shown. Electric power from a power source 207 is supplied to an electric motor 206.
The voltage and current waveforms are measured by the waveform processing system 208. As the motor 206, an AC motor such as a stepping motor of a conventional control rod drive mechanism, an induction motor, and a synchronous motor can be considered. In general, these motors are driven by the magnitude of the current, the voltage and the magnitude of the load power, that is, the load torque. The phase difference of the current waveform changes. Therefore, by providing the waveform processing system 208 between the electric motor 206 and the power supply 207, the current value and the phase difference are detected, and the load torque is estimated.

The phase can be detected relatively easily by, for example, a method of converting a waveform from analog to digital, taking it into a computer, and performing numerical processing. Here, a mechanical phenomenon that occurs in the magnet coupling portion when a slip occurs will be described with reference to a cross-sectional view of the magnet coupling in FIG. As an example of occurrence of slip, a case is considered in which the inner rotor 67 cannot rotate due to damage to the ball screw shaft 14 or the like during driving by the electric motor 206 in FIG. When the torque of the electric motor 206 is larger than the maximum static friction torque of the magnet coupling, the outer rotor 64 continues to rotate, and slip occurs. When the deviation angle is smaller than the slip occurrence angle, the outer rotor 64 of FIG. 4A receives a torque in the illustrated direction from the inner rotor 67 by the action of the magnetic force. This is transmitted to the electric motor as a load torque while the electric motor is being driven, and transmitted to the electromagnetic brake 21 when the control rod fixed position is being held. When the outer rotor 64 further rotates and the deviation angle exceeds the slip occurrence angle, the direction of the torque received is reversed as shown in FIG. If slips occur continuously,
An alternating torque is observed. FIG. 5 conceptually shows this state. The maximum value of the generated torque is almost the same as the maximum static torque, and the sign is reversed at the slip occurrence angle.

Further, the coupling between the outer rotor 64 and the rotating shaft 11 of the electric motor 206 in FIG. 3 is a mechanical coupling which can be easily disengaged with a gear coupling or the like in order to facilitate the overhaul of the electric motor 206. (Not shown), this type of coupling usually has small play in the rotational direction. Due to such play,
When the direction of the torque is reversed, a large impact torque is momentarily generated in the coupling portion and transmitted to the electric motor 206. Therefore, the load of the electric motor 206 includes a high-frequency torque component.

On the other hand, in the normal operating state without slip, as described above, the rated load torque is designed to be sufficiently smaller than the maximum static torque. Never join.

The present embodiment has been made by paying attention to the feature that a large torque is generated when slippage occurs and the direction of the torque is reversed among the above-mentioned mechanical phenomena. By detecting the motor load torque based on the phase difference between the voltage and the current of the motor or the change in the current value, it is possible to detect slippage of the magnet coupling that occurs during driving of the motor.

Hereinafter, the fourth embodiment of the control rod driving mechanism according to the present invention will be described.
(Corresponding to claims 6 and 7) will be described with reference to FIG. In the present embodiment, similarly to the third embodiment, there is no change in the control rod drive mechanism 50 and the spool piece 56 in FIG. Electric power from the power supply 207 is supplied to the electric motor 206,
The frequency analysis of the current or voltage waveform is performed by the frequency analysis system 209. This embodiment focuses on the feature that a high-frequency load torque component is generated in the electric motor 206 among the mechanical phenomena at the time of occurrence of slip described in the third embodiment. Due to such a load torque, a high frequency component that is not seen during normal driving is observed in the current waveform or the voltage waveform, so that the occurrence of slip can be detected by the frequency analysis described above.

Hereinafter, the fifth embodiment of the control rod driving mechanism according to the present invention will be described.
An embodiment (corresponding to claim 8) will be described with reference to FIG. In the present embodiment, the control rod drive mechanism 50 of FIG.
Since there is no change in the spool piece 56, only the peripheral portion of the electric motor is shown. In the present embodiment, an induction motor 210 is used as the electric motor. The rotation speed of the induction motor 210 is determined by a rotation position detection device 211 provided as load torque detection means and a data processing system 2 connected thereto.
12 and is detected. As the rotation position detection device 211,
For example, the synchro position detector 22 of the current control rod drive device
Etc. can be used.

In general, the rotational speed of the induction motor is such that the load is zero.
In the case of, the synchronous speed determined from the frequency of the AC power supply has a fixed relationship unique to each electric motor, and is represented by a curve graph called a torque-rotation characteristic. Therefore, the rotation speed of the induction motor is measured by the rotation position detection device 211,
The load torque can be obtained from the torque-rotation characteristics of the electric motor using the data processing system 212.

Therefore, the change in the load torque at the time of occurrence of slip described in the description of the third embodiment can be detected as a change in the rotation speed of the motor, and the occurrence of slip can be detected. Hereinafter, a sixth embodiment (corresponding to claims 9 and 10) of a control rod driving mechanism according to the present invention will be described with reference to FIG. In the present embodiment, the control rod drive mechanism 50 of FIG.
Since there is no change in the spool piece 56, the electric motor 213
Only the peripheral part is shown. The outer rotor 64 connected to the rotating shaft 215 of the electric motor 213 and the rotor 2 of the electric motor 213
A torque detector 214 for detecting the torque of the electric motor 213 is provided at an intermediate portion between the torque detector 214 and the motor 16. Torque detector 214
For example, a strain gauge type torque detector, a magnetostrictive torque detector, or the like can be used, and the torque of the rotating shaft 215 when it is stationary and when it is rotating can be detected. The output waveform of the torque detector 214 is converted to a data processing system 217.
By analyzing the magnitude and direction of the torque by performing the above processing, the torque at the time of occurrence of slip described in the description of the third embodiment can be detected. The rotor 21 of the electric motor 213
An electromagnetic brake 21 is provided below 6.

Hereinafter, the seventh embodiment of the control rod driving mechanism according to the present invention will be described.
An embodiment (corresponding to claims 11 and 12) will be described with reference to FIG. Also in the present embodiment, since there is no change in the control rod drive mechanism 50 and the spool piece 56 in FIG. 15, only the peripheral portion of the electric motor 218 is shown. The torque generated in the magnet coupling at the time of slippage described in the third embodiment is transmitted from the rotor 216 to the stator 221 while the electric motor 218 is being driven. The stator 221 and the stator 221 are connected to the reactor pressure vessel 1
The torque is applied to the electric motor casing 219, the spool piece 56, and the CRD housing (not shown), which are members to be fixed to the motor, by this torque.

On the other hand, while the control rod is held at the fixed position, the power is transmitted from the rotating shaft 215 to the motor casing 219 via the electromagnetic brake 21, so that the electromagnetic brake 21, the motor casing 219, the spool piece 56, and the CRD housing are twisted. .

In the present invention, means for detecting the torsional distortion of the above-mentioned members is provided, and the torsional distortion accompanying the torque at the time of occurrence of slip is detected. In FIG. 9, as an example of the means for detecting torsion, a distortion detector 220 and a data processing system 22 for processing the output are provided on the surface of the motor casing 219.
2 is installed. For example, a method of installing the strain detector 220 is determined so that a strain gauge can be detected. Note that the installation position of the strain detector 220 is not limited to FIG. 9 and may be anywhere on a member that is torsioned by the torque caused by the slippage described above.

Hereinafter, an eighth embodiment of the control rod driving mechanism according to the present invention will be described.
(Corresponding to claims 13 and 14) will be described with reference to FIGS. 10 to 12. FIG. Also in the present embodiment, since there is no change in the control rod drive mechanism 50 and the spool piece 56 in FIG. 15, only the peripheral portion of the electric motor 223 is shown. The motor 223 is provided with an acceleration sensor 224 that detects acceleration in the circumferential direction of the motor 223. That A
FIG. 11 shows a section taken along the line −A ′. When torsional vibration occurs in the electric motor 223, the acceleration sensor 224 can measure the angular acceleration of the vibration.

The torque generated by the slip is generated by the electric motor 22.
3, the torque of the high frequency component due to the play of the mechanical coupling described in the description of the third embodiment in particular generates torsional vibration with a large angular acceleration.
By detecting this with the acceleration sensor 224, slip can be detected.

When a plurality of acceleration sensors 224 are provided, angular acceleration can be detected more reliably. For example, FIG.
, Two acceleration sensors 224 are installed point-symmetrically with respect to the motor shaft 215. When the acceleration sensor 224 uses a straight acceleration in the y direction (a direction parallel to the acceleration detection direction) shown in the figure, as shown in FIG. In this case, positive and negative outputs are different, and these can be easily distinguished.

[0064]

As described above, in the control rod driving mechanism of the present invention, the first to fourth aspects of the present invention provide the control rod driving mechanism of the first aspect.
By detecting the rotation position of the magnet and comparing it with the rotation position of the second magnet, slip of the magnet coupling can be detected, and the reliability of the plant can be further improved.

In the invention according to claims 5 to 14,
With the slip, the torque generated by the magnet coupling is detected from changes in the phase difference between the current and voltage of the current machine, the current value, and the torsional distortion generated in the motor casing and the like, and the slip can be detected. As a result, the reliability of the plant can be further improved.

[Brief description of the drawings]

1A is a longitudinal sectional view showing a first embodiment of a control rod driving mechanism according to the present invention, and FIG.
-B line arrow sectional drawing.

FIG. 2 is a longitudinal sectional view showing a second embodiment of the control rod drive mechanism according to the present invention.

FIG. 3 is a longitudinal sectional view showing a third embodiment of the control rod drive mechanism according to the present invention.

FIGS. 4A and 4B are conceptual diagrams for explaining a mechanical phenomenon that occurs when slippage occurs in a magnet coupling portion.

FIG. 5 is a conceptual diagram for explaining a mechanical phenomenon that occurs when slippage occurs in the magnet coupling unit.

FIG. 6 is a longitudinal sectional view showing a fourth embodiment of the control rod drive mechanism according to the present invention.

FIG. 7 is a longitudinal sectional view showing a fifth embodiment of the control rod drive mechanism according to the present invention.

FIG. 8 is a longitudinal sectional view showing a control rod drive mechanism according to a sixth embodiment of the present invention.

FIG. 9 is a longitudinal sectional view showing a control rod driving mechanism according to a seventh embodiment of the present invention.

FIG. 10 is a longitudinal sectional view showing an eighth embodiment of the control rod drive mechanism according to the present invention.

FIG. 11 is a conceptual diagram showing an installation position of an acceleration sensor in an eighth embodiment of the control rod driving mechanism according to the present invention.

FIG. 12A is a conceptual diagram illustrating an output example of a linear acceleration of an acceleration sensor according to an eighth embodiment of the control rod driving mechanism according to the present invention, and FIG. 12B is a conceptual diagram illustrating an output example of a rotational acceleration. FIG.

FIG. 13 is a conceptual diagram showing the structure of a boiling water reactor.

FIG. 14 is a longitudinal sectional view showing a conventional example of a control rod drive mechanism.

FIG. 15 is a longitudinal sectional view showing the structure of a magnet type control rod driving mechanism.

FIG. 16 is a cross-sectional view for explaining the driving principle of the magnet type control rod driving mechanism.

FIG. 17 is a cross-sectional view for explaining the driving principle of the magnet-type control rod driving mechanism.

FIG. 18 is a conceptual diagram showing a relationship between a deviation angle of a magnetic coupling and a torque.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Reactor pressure vessel 1a ... Bottom part 2 ... Coolant 3 ... Core 4 ... Core shroud 5 ... Control rod 6 ... Steam separator 7 ... Downcomer part 8 ... Control rod drive mechanism 9 ... CRD housing 9a ... Lower flange 10 ... Electric motor 11 ... Rotating shaft 12 ... Gear coupling mechanism 13 ... Drive shaft 14 ... Ball screw shaft 15 ... Ball nut 16 ... Roller 17 ... Guide tube 18 ... Mounting plate 19 ... Hollow piston 20 ... Coupling 21 ... Electromagnetic brake 22 ... Synchro Position detector 23 ... Motor bracket 24 ... Spool piece 25 ... Gland packing 26 ... O-ring 27 ... O-ring 31 ... Top guide 32 ... Disc spring mechanism 33 ... Scrum insertion pipe 34 ... Injection port 35 ... Lead switch 35 ... Reed switch 36 ... Scrum position detector 50 ... Control rod drive mechanism 51 ... Electric motor 52 ... Gunnet coupling 53 Drive shaft 54 Inner magnet 55 Outer magnet 56 Spool piece 57 Motor bracket 58 Pressure barrier 60 Outer yoke 61 Inner yoke 64 Outer rotor 67 Inner rotor 199 Spool piece 200 Rotation Member 201 Position detecting device 202 Signal processing system 203 Rotational position detecting device 204 Control rod position detecting device 205 Signal processing system 206 Electric motor 207 Power supply 208 Waveform processing system 209 Frequency analysis system 210 Induction motor 211 ... Rotary position detecting device 212 ... Data processing system 213 ... Electric motor 214 ... Torque detector 215 ... Rotating shaft 216 ... Rotor 217 ... Data processing system 218 ... Electric motor 219 ... Electric motor casing 220 ... Strain detection 221 ... stator 222 ... data processing system 223 ... motor 224 ... acceleration sensor

Claims (14)

[Claims] 1. A control provided in a housing extending below a reactor to transmit the rotation of an electric motor to a hollow piston elevating mechanism via a drive shaft to elevate and lower the hollow piston, and to engage the hollow piston. In a control rod drive mechanism of a reactor power for inserting and withdrawing a rod into a reactor core, a spool piece provided at a lower end portion of the housing to seal primary cooling water inside the reactor, and a lower portion of an outer lower portion of the spool piece. An outer yoke connected to a rotating shaft of the electric motor provided, an outer magnet provided on the outer yoke, and a drive shaft provided inside the spool piece and connected to the hollow piston lifting mechanism. A control, comprising: an inner yoke, an inner magnet provided on the inner yoke, and rotation detecting means for the inner magnet. Rod drive mechanism. A rotation member provided on a drive shaft that rotates with the inner magnet, the rotation member having an uneven surface formed on a side surface thereof; and a rotation member provided opposite to a rotation horizontal plane of the rotation member. 2. The control rod driving mechanism according to claim 1, further comprising: a displacement detector for measuring a distance from the unevenness formed on the side surface. 3. An output processing means for comparing the output from the rotation detection means of the inner magnet with the output from a rotation position detection means for detecting the rotation of the rotating shaft of the electric motor. A control rod drive mechanism as described. 4. The control rod drive mechanism according to claim 3, further comprising a vertical position detecting means for detecting a vertical position of the control rod by inserting and extracting the control rod, instead of the inner magnet rotation detecting means. 5. A control provided in a housing extending below the reactor to transmit the rotation of an electric motor to a hollow piston elevating mechanism via a drive shaft to elevate and lower the hollow piston and engage the hollow piston. In a control rod drive mechanism of a reactor power for inserting and withdrawing a rod into a reactor core, a spool piece provided at a lower end portion of the housing to seal primary cooling water inside the reactor, and a lower portion of an outer lower portion of the spool piece. An outer yoke connected to a rotating shaft of the electric motor provided, an outer magnet provided on the outer yoke, and a drive shaft provided inside the spool piece and connected to the hollow piston lifting mechanism. An inner yoke, an inner magnet provided on the inner yoke, and a phase difference between a current and a voltage of the motor are detected to estimate a torque of the motor. And a control rod driving mechanism. 6. A control provided in a housing extending below the reactor to transmit the rotation of an electric motor to a hollow piston elevating mechanism via a drive shaft to elevate and lower the hollow piston and engage the hollow piston. In a control rod drive mechanism of a reactor power for inserting and withdrawing a rod into a reactor core, a spool piece provided at a lower end portion of the housing to seal primary cooling water inside the reactor, and a lower portion of an outer lower portion of the spool piece. An outer yoke connected to a rotating shaft of the electric motor provided, an outer magnet provided on the outer yoke, and a drive shaft provided inside the spool piece and connected to the hollow piston lifting mechanism. An inner yoke, an inner magnet provided on the inner yoke, and frequency analysis means for a current waveform of the electric motor. Control rod drive mechanism. 7. The control rod drive mechanism according to claim 6, further comprising a voltage waveform frequency analyzing means instead of the current waveform frequency analyzing means of the electric motor. 8. A control provided in a housing extending below the reactor to transmit rotation of an electric motor to a hollow piston elevating mechanism via a drive shaft to elevate and lower the hollow piston and engage with the hollow piston. In a control rod drive mechanism of a reactor power for inserting and withdrawing a rod into a reactor core, a spool piece provided at a lower end portion of the housing to seal primary cooling water inside the reactor, and a lower portion of an outer lower portion of the spool piece. An outer yoke connected to a rotating shaft of the electric motor provided, an outer magnet provided on the outer yoke, and a drive shaft provided inside the spool piece and connected to the hollow piston lifting mechanism. An inner yoke, an inner magnet provided on the inner yoke, and a load torque detecting means for the electric motor, wherein the electric motor is an induction motor A control rod driving mechanism, wherein the load torque detecting means detects a load torque from a rotation speed of the electric motor. 9. A control provided in a housing extending below the reactor to transmit rotation of an electric motor to a hollow piston elevating mechanism via a drive shaft to elevate and lower the hollow piston and engage with the hollow piston. In a control rod drive mechanism of a reactor power for inserting and withdrawing a rod into a reactor core, a spool piece provided at a lower end portion of the housing to seal primary cooling water inside the reactor, and a lower portion of an outer lower portion of the spool piece. An outer yoke connected to a rotating shaft of the electric motor provided, an outer magnet provided on the outer yoke, and a drive shaft provided inside the spool piece and connected to the hollow piston lifting mechanism. An inner yoke, an inner magnet provided on the inner yoke, and a torque applied to a rotating shaft of the electric motor or a drive connected to the electric motor. A control rod driving mechanism, comprising: a torque detecting means for detecting a torque applied to a shaft. 10. The control rod drive mechanism according to claim 9, further comprising a slip detecting means for detecting a slip generated between the outer magnet and the inner magnet using the detected torque. 11. A control provided in a housing extending below the reactor to transmit rotation of an electric motor to a hollow piston elevating mechanism via a drive shaft to elevate and lower the hollow piston and engage with the hollow piston. Insert the rod into the reactor core
In the control rod drive mechanism of the reactor power to be pulled out, the spool piece is provided at the lower end of the housing and seals the primary cooling water inside the reactor, and is connected to a rotating shaft of the electric motor provided at an outer lower portion of the spool piece. An outer yoke, an outer magnet provided on the outer yoke, an inner yoke provided on the drive shaft provided inside the spool piece and connected to the hollow piston lifting / lowering mechanism, and provided on the inner yoke. A control rod driving mechanism, comprising: an inner magnet; and a distortion detecting means for detecting distortion generated in a stator of the electric motor or a member fixing the stator to a reactor pressure vessel. 12. The apparatus according to claim 1, further comprising a strain detecting means for detecting a strain generated in a member for fixing the brake to the reactor pressure vessel or a brake for restricting the rotation of the rotating shaft, in place of the strain detecting means. A control rod drive mechanism according to claim 11. 13. A control provided in a housing extending below the nuclear reactor to transmit rotation of an electric motor to a hollow piston elevating mechanism via a drive shaft to elevate and lower the hollow piston and engage with the hollow piston. Insert the rod into the reactor core
In the control rod drive mechanism of the reactor power to be pulled out, the spool piece is provided at the lower end of the housing and seals the primary cooling water inside the reactor, and is connected to a rotating shaft of the electric motor provided at an outer lower portion of the spool piece. An outer yoke, an outer magnet provided on the outer yoke, an inner yoke provided on the drive shaft provided inside the spool piece and connected to the hollow piston lifting / lowering mechanism, and provided on the inner yoke. A control rod drive mechanism comprising: an inner magnet; and an acceleration detecting means for detecting a rotational acceleration generated in a stator of the electric motor or a member fixing the stator to a reactor pressure vessel. 14. An acceleration detecting means for detecting a rotational acceleration generated on a member for fixing the brake to a reactor pressure vessel or a brake for restricting the rotation of the rotating shaft, in place of the acceleration detecting means. Item 14. The control rod driving mechanism according to Item 13.