JPH1026685A - Control-rod drive mechanism, controller and operation method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a simple structure which has no shaft seal part, realize high reliability and facilitate maintenance and inspections by adopting a linear reluctance motor to directly impart a linear movement of a drive shaft connected with a control rod. SOLUTION: A linear reluctance motor 19 inserts a drive shaft 18 into a stator iron core 24 so that the drive shaft 18 can freely move vertically to control the current of a fixed coil 26. Consequently, electromagnetic attraction and repulsion force are generated between teeth 25 of the iron core 24 and teeth 29 of the drive shaft 18 as driving force to the direction in which the drive shaft advances. This allows the drive shaft 18 connected with a control rod 1 in a reactor pressure vessel 9 to linearly and smoothly move vertically without coming in contact with a stator. As a result, the drive shaft 18 has no penetration part in a housing 17 for a control rod drive mechanism outside the pressure vessel 9, which eliminates the necessity to install shaft seal part. Therefore, such a simple structure reduces the frequency of maintenance and inspections and improves the reliability of a sealing part at the bottom of the pressure vessel 9.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a boiling water reactor and a fast breeder reactor, and more particularly, to a control rod drive mechanism which is built in a reactor and adjusts output by inserting or removing a control rod. The present invention relates to a control device and an operation method.

[0002]

2. Description of the Related Art In a boiling water reactor or a fast breeder reactor, the power of the reactor is adjusted by controlling the reactivity by inserting or removing a control rod made of a neutron absorbing material into the core. The control rod is inserted or withdrawn by moving the connecting pipe connected to the control rod up and down by the control rod drive mechanism. For a conventional control rod drive mechanism using a boiling water reactor as an example,
As shown in the longitudinal sectional views of FIGS. 10 and 11, the control rod 1 in the furnace
The control rod drive mechanism 3 is connected to the connection pipe 4 via the coupling 2.

[0003] A ball screw 5 is inserted into the connection pipe 3, and the ball screw 5 is further connected to a drive motor 7 via a motor coupling 6. A ball nut 8 is screwed to the ball screw 5 so as to be vertically movable. The connection nut 4 is supported by the ball nut 8 together with the control rod 1. Therefore, when the ball screw 5 is rotated by the drive motor 7, the connection pipe 4 is driven up and down by the ball nut 8, so that the control rod 1 is inserted into or pulled out of the core.

Since the drive motor 7 is installed outside the reactor pressure vessel 9, a shaft sealing portion 10 is provided between the drive motor 7 and the ball screw 5 so that the reactor pressure vessel 9
Has a sealed structure that seals the inside from outside with water. Also,
At the time of the reactor scram, the scram water 11 is injected from the lower part of the control rod drive mechanism housing 12 so that the connecting rod 4 mounted and supported on the ball nut 8 is released from the ball nut 8 by water pressure and pushed up. The rod 1 is quickly inserted into the furnace.

As shown in the longitudinal sectional view of FIG. 11, the control rod drive mechanism 3 in the reactor pressure vessel 9 has a length of the control rod 1 approximately equal to the height of the reactor core 13 and about 4 m.
The moving stroke of the control rod 1 in the core 14 by the control rod guide tube 13 is approximately the same as the height of the core 14 and is about 4 m. Therefore, in order to secure the stroke of the control rod 1, the length of the connecting pipe 4 also needs to be about 6 m.

As shown in FIG. 10, the control rod drive mechanism 3 penetrates the reactor pressure vessel 9 and is fixed to the lower part of the reactor pressure vessel 9 by welding.
The housing flange 12a and the shaft sealing end plug flange 15a of the shaft sealing end plug 15 to which the drive motor 7 is mounted are fixed to the reactor pressure vessel 9 by bolting.

The control rod 1 and the control rod guide tube 13 are attached and detached from the upper side of the reactor pressure vessel 9, but the control rod drive mechanism 3 is attached and detached from the lower side of the reactor pressure vessel 9. Have been done. For this purpose, below the reactor pressure vessel 9
A high space for pulling out the control rod drive mechanism 3 having a length of about 4 m downward is required.

[0008]

In the control rod driving mechanism 3, the connecting pipe 4 is mounted on a ball screw 5 and a ball nut 8 and is detachably supported. Since the structure is complicated, high-precision processing is performed. Is necessary and expensive. Further, in order to ensure the reliability of operation, it is necessary to frequently perform maintenance and inspection.

Further, since the drive motor 7 is installed outside the reactor pressure vessel 9, a shaft seal 10 is provided between the drive motor 7 and the motor coupling 6, and the reactor pressure vessel 9 is provided. The inside of the shaft must be sealed from the outside,
Maintenance and inspections to ensure the reliability of the system had to be performed frequently.

Further, since the control rod drive mechanism 3 is attached to and detached from the lower part of the reactor pressure vessel 9 at a lower portion of the reactor pressure vessel 9, a high and wide space is provided. Therefore, the reactor building accommodating the reactor pressure vessel 9 and the like is large in scale, which leads to an increase in construction costs, and the installation position of the reactor pressure vessel 9 is relatively high, so that the seismic design is There was a disadvantage that was disadvantageous.

An object of the present invention is to employ a linear reluctance motor that directly linearly moves a drive shaft connected to a control rod, and has a simple structure without a shaft sealing portion, high reliability, and high maintenance and maintenance. It is an object of the present invention to provide a control rod drive mechanism that can be easily inspected and does not require many places for attachment and detachment, and a control device and an operation method thereof.

[0012]

In order to achieve the above object, a control rod driving mechanism according to the present invention is provided so as to penetrate a reactor pressure vessel and insert or withdraw a control rod into or from a reactor core. In a control rod drive mechanism, a control rod drive mechanism housing whose upper part is fixed to the reactor pressure vessel and whose lower part is sealed with a closed end plug is connected to a control rod in the reactor pressure vessel. A linear reluctance motor including a drive shaft having a tooth profile formed on an outer periphery that moves up and down, a stator core and a stator coil having a tooth profile formed on an inner periphery of a stator that movably drives the drive shaft; A latch mechanism that holds the control rod by locking to the tooth form;
A position detector is provided for detecting the insertion position of the control rod using the tooth shape of the drive shaft or a magnet mounted on the tooth shape.

The control rod drive mechanism is fixed to the lower part of the reactor pressure vessel and has good sealing performance because there is no shaft seal. The linear reluctance motor allows the control rod to be inserted or withdrawn directly, resulting in a linear motion. It is performed in. The insertion position of the control rod is detected by the position detector, and after reaching the predetermined position, it is held by the latch mechanism, and the power of the linear reluctance motor is turned off. After the power is turned on and the driving force is generated, the latch mechanism is released and then driven to a predetermined position.

A control rod driving mechanism according to a second aspect of the present invention is characterized in that the linear reluctance motor is an underwater motor installed underwater in the control rod driving mechanism housing. Since the linear reluctance motor is an underwater motor having a waterproof structure, the linear reluctance motor can be operated without any trouble against water sealing in the control rod drive mechanism housing or intrusion water from the reactor pressure vessel, and maintenance and inspection can be easily performed.

According to a third aspect of the present invention, in the control rod driving mechanism, the linear reluctance motor, which is an underwater motor, is a cand type in which a stator core and a stator coil are watertightly surrounded by a can. And Since the stator structure as a submersible motor has a waterproof structure in which a stator core and a stator coil are water-tightly surrounded by a can, the waterproofness and insulation are good, and maintenance and inspection are easy.

According to a fourth aspect of the present invention, there is provided a control rod driving mechanism, wherein a linear reluctance motor as an underwater motor is formed by molding a stator core and a stator coil of a stator with resin. Since the underwater motor has a waterproof structure in which the stator core and the stator coil of the stator are molded with resin, the insulating property is good, the waterproof property is excellent, and the maintenance and inspection are easy.

According to a fifth aspect of the present invention, in the control rod driving mechanism, a linear reluctance motor as an underwater motor is a canned type in which a stator iron core and a stator coil of a stator are molded with resin and water-tightly surrounded by a can. It is characterized by having. As a submersible motor, the stator core and stator coil of the stator are molded with resin, and are watertightly sealed with a can.
High reliability and easy maintenance and inspection.

According to a sixth aspect of the present invention, in the control rod driving mechanism, the control rod driving mechanism injects scram water into the control rod driving mechanism housing, and rapidly drives the control rod through the drive shaft by water pressure. It is characterized by being inserted into the inside. Even when it is difficult to quickly insert a control rod by a linear reluctance motor due to loss of power or the like during a reactor scram, the control rod can be quickly inserted into the reactor core by the water pressure of the scram water.

According to a seventh aspect of the present invention, in the control rod drive mechanism, the drive shaft can be pulled out of the control rod drive mechanism housing to the upper part of the reactor pressure vessel, and the stator and the position are detected. The vessel and the latch mechanism are characterized in that they can be pulled out from the lower part of the reactor pressure vessel integrally or separately.

The long drive shaft is pulled out to the upper part of the reactor pressure vessel, and the linear reluctance motor stator, the position detector and the latch mechanism are integrally or separately reduced in height and taken out from the lower part of the reactor pressure vessel. The height of the lower space of the reactor pressure vessel can be reduced.

In a control rod driving mechanism according to an eighth aspect of the present invention, the linear reluctance motor includes a plurality of linear reluctance motors installed coaxially, and the tooth profile of the drive shaft and the tooth profile of the stator core of each linear reluctance motor. It is characterized in that the positions are shifted. Since the tooth profile of the stator core of each of the multiple linear reluctance motors is shifted relative to the tooth profile position of the drive shaft, the fluctuation range of the total thrust that is the driving force of the drive shaft is small, and the minimum total thrust Is greatly obtained.

According to a ninth aspect of the present invention, in the control rod driving mechanism, a plurality of linear reluctance motors are installed coaxially, and a current having a phase shifted is supplied to a stator coil of each linear reluctance motor. And Since the phases of the currents supplied to the stator coils of each of the plurality of linear reluctance motors are shifted, the fluctuation range of the total thrust is small and the minimum total thrust is large.

According to a tenth aspect of the present invention, in the control rod driving mechanism, the linear reluctance motor divides the stator into a plurality of parts in the axial direction, and sets the tooth shape of the drive shaft and the tooth shape of the stator core of each stator. It is characterized in that the relative positions are shifted. Since the relative position between the tooth profile of the drive shaft and the tooth profile of the stator core in each of the stators that are divided is shifted, the fluctuation range of the total thrust that is the driving force of the drive shaft is small, and the minimum total thrust is large. can get.

In a control rod driving mechanism according to an eleventh aspect of the present invention, the linear reluctance motor divides the stator coil of the stator into a plurality in the axial direction and supplies a current having a phase shifted to each stator coil. It is characterized by the following. Since the phases of the currents supplied to the plurality of stator coils are shifted, the fluctuation range of the total thrust is small, and the minimum total thrust is large.

According to a twelfth aspect of the present invention, there is provided a control rod driving mechanism for a control rod driving mechanism having a linear reluctance motor, wherein the power supply inverter converts power supply power into a predetermined frequency and phase, a voltage, a current or the like. A control rod position control device for inputting a control rod position command signal, a scrum signal, and a position signal and outputting a latch operation signal together with control rod information; and And a speed control device for performing the control rod operation.

In response to the control rod information and the latch operation signal from the control rod position control device, the speed control device operates the control rod drive mechanism to a predetermined position at an appropriate speed and moving distance via a power inverter. .

According to a thirteenth aspect of the present invention, there is provided a driving method of a control rod driving mechanism having a linear reluctance motor, wherein the driving shaft connected to the control rod is driven by the linear reluctance motor and the driving shaft of the driving shaft is provided. The drive speed is varied from a predetermined control rod insertion or withdrawal speed to a scrum insertion speed by varying the power supply frequency of the linear reluctance motor. By varying the power supply frequency supplied to the linear reluctance motor of the control rod drive mechanism, the control rod can be arbitrarily changed from a predetermined insertion or withdrawal speed to a scrum insertion speed, and the control rod can be operated over a wide range of speeds.

According to a fourteenth aspect of the present invention, in the control rod driving mechanism having a linear reluctance motor, the drive shaft is rapidly driven by the linear reluctance motor by inputting a scrum signal. The reactor is scrammed by rapid insertion of a rod. By rapidly driving the linear reluctance motor, the reactor can be scrammed by rapidly inserting the control rod into the core.

A method of operating a control rod drive mechanism according to the invention according to claim 15 is a control rod drive mechanism having a linear reluctance motor, wherein a signal detecting a transient phenomenon occurring in a reactor plant is input to a control device. Control the frequency and phase of the power supplied to the linear reluctance motor by controlling the output of the reactor by rapidly inserting or extracting the control rod into or from the reactor core via the drive shaft, resulting in an excessive pressure increase or temperature increase of the reactor. It is characterized in that a rise or a rapid drop in temperature is avoided.

A detection signal of transient phenomena in the reactor plant is input to a controller, and the driving force of the linear reluctance motor is controlled by the detection signal of the transient phenomena. By the output control, a transient phenomenon in the nuclear reactor plant can be easily mitigated.

The control device for a control rod drive mechanism according to the invention of claim 16 is the control device, wherein the power input side of the power inverter is provided with an uninterruptible power supply comprising a battery and an uninterruptible inverter, or a flywheel and an induction motor. It is characterized in that an uninterruptible power supply by a power failure inverter is provided.

When the external power supply is lost or the power supply fluctuates due to a momentary power failure, the uninterruptible power supply supplies uninterrupted power from the battery DC or the inertia energy of the flywheel. Can be performed without any trouble.

[0033]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to the drawings, taking a boiling water reactor as an example. In addition,
Similarly, the same components as those of the above-described prior art are denoted by the same reference numerals, and detailed description is omitted. In the first embodiment, the control rod drive mechanism 16 has the control rod drive mechanism housing 17 at the upper part and penetrates the reactor pressure vessel 9 as shown in the longitudinal sectional view of FIG. And fixed to the bottom of the reactor pressure vessel 9 by welding.

Inside the control rod drive mechanism housing 17,
A linear reluctance motor 19, which is driven up and down freely, is installed through a drive shaft 18 connected via a coupling 2 to a control rod 1 inserted or withdrawn into the reactor in the reactor pressure vessel 9. . In addition, a position detector 20 and a latch mechanism 21 are installed around the drive shaft 18 below the linear reluctance motor 19, and the lower end is water-tightly sealed with a closed end plug 22 to form a housing flange 17a. The closed end plug flange 22a is configured to be tightened with a bolt (claim 1).

The linear reluctance motor 19 has a structure shown in FIG.
3 and a drive shaft 18 shown in a perspective view of a main part of FIG. 3. The stator 23 has a tooth profile 25 and a groove provided inside a stator core 24, and is fixed in this groove. A child coil 26 is provided. Further, the linear reluctance motor 19 can be operated without any trouble in the control rod drive mechanism housing 17, particularly, with respect to water sealing or scrum water 11 interposed between the drive shaft 18 and the inside of the stator core 24. It has the structure of a submersible motor (claim 2).

In this underwater motor, both the stator core 24 and the stator coil 26 are of a cand type surrounded by a corrosion-resistant metal or resin can 27, or the stator core 24 and the stator coil 26 are both used. The resin mold 28 is treated with a resin, or both the can 27 and the resin mold 28 are treated (claims 3 to 5). As shown in FIG. 1, a drive shaft 18 is provided below the control rod drive mechanism housing 17 in order to quickly insert the control rod 1 during a reactor scram.
An injection pipe 31 for the scrum water 11 for applying water pressure is provided at a lower portion of the water supply tank (claim 6).

The drive shaft 18 installed in the control rod drive mechanism housing 17 has a simple shape in which a tooth profile 29 and a groove 30 are formed on the outer periphery.
Can be pulled out to the upper part of the reactor pressure vessel 9 during maintenance and inspection of the reactor. Further, the stator 23 including the stator core 24 and the stator coil 26 is integrated as a submersible motor, and is integrated with or separated from the lower part of the reactor pressure vessel 9 together with the position detector 20 and the latch mechanism 21. It can be pulled out (claim 7).

The position detector 20 is disposed close to the outer periphery of the drive shaft 18 as shown in FIG.
The insertion position of the control rod 1 in the core is directly detected from the position of the drive shaft 18 through the tooth profile 29 of FIG. In addition, the tooth profile 29 of the drive shaft 18 is in the state as it is,
A mirror finish (not shown), a reflection plate is attached, or a permanent magnet is buried in advance as a mark for position detection. The position detector 20 for the tooth profile 29 includes proximity detection of the movement of the tooth profile 29 corresponding to the vertical movement of the control rod 1, light detection by a mirror surface or a reflection plate, and a magnetic detection unit.

The latch mechanism 21 shown in FIG.
a is provided, and the claw 21 a is provided in the groove 30 of the drive shaft 18.
The control rod 1 is held via the drive shaft 18 by engaging with the tooth profile 29 between the two.

Next, the operation of the above configuration will be described. In the linear reluctance motor 19, the stator 23
By vertically inserting the drive shaft 18 inside the stator core 24 to control the current of the stator coil 26,
An electromagnetic attractive force and a repulsive force are generated between the tooth profile 25 of the stator core 24 and the tooth profile 29 of the drive shaft 18 as a driving force in the traveling direction of the drive shaft 18.

Accordingly, it is possible to linearly and smoothly move up and down with respect to the drive shaft 18 connected to the control rod 1 in the furnace in a non-contact state with the stator 23 and to hold it at an arbitrary position. . Also, the linear reluctance motor 19
Since it is installed in the control rod drive mechanism housing 17 as a submersible motor and drives the drive shaft 18 connected to the control rod 1 in the furnace up and down, it comes into contact with the reactor water from the reactor pressure vessel 9 together with the sealed water. There is.

However, since the stator 23 is a canned type surrounded by a can 27 made of a corrosion-resistant metal or resin, or is molded with resin, the stator core 24 and the stator coil 26 are not immersed in water. High reliability because it does not corrode. Further, in the case of the cand type, even if the surface is contaminated with reactor water, the cleaning can be performed without any trouble, so that maintenance and inspection are easy and there is an effect of reducing the exposure of workers.

Since the drive shaft 18 does not have a portion penetrating through the control rod drive mechanism housing 17 and the like outside the reactor pressure vessel 9, it is not necessary to provide a shaft sealing portion. Accordingly, the control rod drive mechanism 16 does not require maintenance and inspection of the shaft sealing portion and the like, and the control rod drive mechanism housing 17 is easily watertightly sealed by the closed end plug 22 at the lower end, thereby improving reliability. .

Since the long drive shaft 18 has a simple shape only with the tooth profile 29 provided on the outer periphery, the maintenance and inspection are infrequent and the work is simple, and the maintenance and inspection of the control rod 1 are sufficient. It can be withdrawn from above into the reactor pressure vessel 9 which stores water for shielding radiation at an appropriate depth. Also, the linear reluctance motor 19 and the position detector 20
The latch mechanism 21 has a structure that can be taken out of the control rod drive mechanism housing 17 to the lower part of the reactor pressure vessel 9 integrally or separately.

For this reason, the space for maintenance and inspection provided at the lower part of the reactor pressure vessel 9 may be sufficient if the space for pulling out the stator 23 of the linear reluctance motor 19 having a low height is sufficient. Therefore, the space height below the reactor pressure vessel 9 is low, and the reactor building can be reduced in construction cost by reducing the reactor building and strengthening the earthquake-resistant structure.

The position detector 20 has a tooth shape of the drive shaft 18.
With 29, the insertion position of the control rod 1 in the core is directly detected from the position of the drive shaft 18 in a non-contact manner, and the control rod position can be detected with high accuracy.

According to the position detector 20, besides the absolute position of the control rod 1 and the speed of the drive shaft 18, the tooth shape 29 of the drive shaft 18 and the stator core 24 for determining the drive direction of the linear reluctance motor 19 are determined. By detecting the relative position with respect to the tooth profile 25 and outputting a signal to the control device of the linear reluctance motor 19, the start, stop and operation of the linear reluctance motor 19 can be controlled.

In the linear reluctance motor 19, since the drive shaft 18 and the stator 23 are not in contact with each other, for example, when the control rod 1 is not operated, the power supply to the linear reluctance motor 19 is cut off. When there is, the electromagnetic force serving as a driving force for holding the driving shaft 18 by the stator 23 is lost. At this time, the latch mechanism 21 is for preventing the drive shaft 18 together with the control rod 1 from dropping by its own weight, and the claw 21a of the latch mechanism 21 is located between the groove 30 of the drive shaft 18 in a normal state. It is locked in the tooth form 29.

Therefore, according to the latch mechanism 21, even when the driving force of the linear reluctance motor 19 is reduced or lost, the control rod 1 is supported together with the driving shaft 18 to maintain the current position. When operating the control rod 1, power is supplied to the linear reluctance motor 19 while the drive shaft 18 is held by the latch mechanism 21, and the drive shaft 18 is held in a direction for holding the control shaft 1 against its own weight including the control rod 1. After the driving force is generated, the latch mechanism 21 is released and the pawl 21a is released from the tooth form 29 of the driving shaft 18.

Next, by applying a driving force to the drive shaft 18 from the stator 23 in a direction corresponding to the direction and speed corresponding to the insertion or withdrawal of the control rod 1 by the linear reluctance motor 19, the control rod 1 is inserted or withdrawn. An operation is performed. The position of the control rod 1 is always determined by the position detector 20.
Is detected and a position signal is output, so that the control device (not shown) can detect that the control rod 1 has reached the predetermined position.

Therefore, when the control rod 1 approaches the predetermined position, the control device controls the driving force of the linear reluctance motor 19 to reduce the moving speed of the control rod 1 and to hold the control rod 1 at the predetermined position. The driving force is used as a driving force, and after confirming that the driving force has reached a predetermined position, the driving force is held by the latch mechanism 21.

It is easy to adjust the position in the vicinity of the predetermined position. After the position is held at the predetermined position by the latch mechanism 21, the power supply to the linear reluctance motor 19 is stopped to eliminate the driving force. Further, during the reactor scram, the control rod 1 must be rapidly inserted into the reactor. In this case, the control rod 1 can be easily driven by rapidly driving the drive rod 18 by the linear reluctance motor 19.

When the power supply is insufficient under the condition of the reactor scram generation, the scram water 11 is injected from the water injection pipe 31 at the lower part of the control rod drive mechanism housing 17 so that the drive shaft 18 is driven by water pressure. By pushing up, the control rod 1 can be rapidly inserted into the core via the coupling 2, so that safety and reliability are high. In addition, by installing an uninterruptible power supply to the power supply of the control rod drive mechanism 16, even in the event of a power failure or instantaneous voltage drop of the external power supply system,
Control rod 1 with linear reluctance motor 19
And the reliability is improved.

The second embodiment relates to claims 8 to 11, and in general, regarding the linear reluctance motor 19,
There is a feature that the fluctuation of the generated thrust is large.Therefore, at the time of high-speed operation, the fluctuation is averaged, and there is no particular problem. Occasionally, a characteristic with a large variation may hinder.

That is, in applications where the drive rod 18 is in a vertical position and a load is constantly applied by its own weight, such as the control rod drive mechanisms 16 and 32, it is difficult to hold or start the drive shaft 18 when the fluctuation value is minimum. Or inconvenience such as occurrence of vibration during low-speed operation.

In the linear reluctance motor of the control rod drive mechanism according to the second embodiment, as a first countermeasure, as shown in a vertical sectional view of FIG.
A plurality of, for example, two linear reluctance motors 19a and 19b are coaxially installed in the 32 control rod drive mechanism housings 17. In addition, each linear reluctance motor 19a, 19b
The tooth shape 25 of the stator core 24 is arranged so that the relative position with respect to the tooth shape 29 of the drive shaft 18 is shifted.

Regarding the control rod drive mechanism 32 of the first measure, the installation of the stator cores 24 of the linear reluctance motors 19a and 19b in the control rod drive mechanism housing 17 requires some mechanical processing. The feature is that the same power supply is sufficient. The other parts are configured in the same manner as in the first embodiment, and the operations and effects obtained thereby are also the same. Therefore, only the points different from the first embodiment will be described below.

Next, the operation of the above configuration will be described. Thrust fluctuations generated by the respective linear reluctance motors 19a and 19b by disposing the two linear reluctance motors 19a and 19b relative to the tooth profile 25 of the stator core 24 with respect to the tooth profile 29 of the drive shaft 18 are shifted. Is complemented.

That is, as shown in the thrust characteristic curve diagram of FIG. 6, the thrust generated by one linear reluctance motor is a dashed-dotted curve 33, and the tooth profile of the stator core 24 is also controlled by one linear reluctance motor. When the relative position of 25 is shifted, the thrust waveform is the same but changes parallel to the drive shaft position, as indicated by the solid curve 34.

Therefore, when two linear reluctance motors are used without shifting the relative positions of the tooth profiles, the total thrust is one thrust (dashed-dotted line 33) as shown by a thick dashed-dotted curve 35. The total minimum thrust value A is small and the range of variation as the total thrust is large.

However, the total thrust when the two linear reluctance motors are used with the relative positions of the tooth profiles shifted from each other is shown by a thick solid line curve 36, and the total maximum thrust value is represented by the thick dashed line. Although smaller than the curve 35, the overall minimum thrust value B is much larger than the overall minimum thrust value A, so that a high quality overall thrust with a very small fluctuation range can be obtained.

From the above, by shifting the relative positions of the tooth profiles with each other with a plurality of linear reluctance motors,
Compared to a case where the tooth profile relative position is not shifted, a much larger minimum thrust can be obtained, and the drive rod 18 can be driven with a stable thrust with little fluctuation.

As a method of complementing the variation in the thrust for driving the drive rod 18 in the linear reluctance motor 19, two (a plurality) of the tooth shapes 29 of the drive shaft 18 are used.
Of linear reluctance motors 19a and 19b and stator core
In addition to the configuration in which the relative positions of the 24 tooth profiles 25 are mechanically shifted, there are the following second to fourth countermeasures, and the same actions and effects as those of the first countermeasure can be obtained.

As a second countermeasure, in the two (a plurality of) linear reluctance motors 19a and 19b provided coaxially, the relative positions of the tooth shapes 25 of the stator cores 24 are not shifted, but the respective stator coils are not shifted. In this case, a current whose phase is shifted is supplied. In the control rod drive mechanism according to the second measure, the control rod drive mechanism housing
The installation work of the two linear reluctance motors 19a and 19b in 17 is simple, but is characterized in that power supplies of two different phases are required.

As a third countermeasure, in one linear reluctance motor 19, the stator 23 is divided into a plurality in the axial direction, and the tooth profile 25 of the stator core 24 of each of the divided stators and the drive shaft The configuration is such that the relative positions of the 18 tooth shapes 29 are shifted from each other (claim 10). The control rod drive mechanism according to the third measure is characterized in that the installation of the two stator cores 24 in the control rod drive mechanism housing 17 requires some mechanical processing, but requires the same power supply. is there.

As a fourth measure, in one linear reluctance motor 19, the stator 23 is divided into a plurality in the axial direction, and the stator core 24 of each of the divided stators 23 is divided.
The relative positions of the tooth profiles 25 are not shifted, but currents with phases shifted from each other are supplied to the respective stator coils (claim 11). The control rod drive mechanism according to the fourth measure is characterized in that the installation work of the two stator cores 24 in the control rod drive mechanism housing 17 is simple, but requires power supplies of two different phases. .

As shown in the control system block diagram of FIG. 7, the control device of the control rod drive mechanisms 16 and 23 by the linear reluctance motor 19 includes a power supply. It is composed of an inverter 37, a control rod position control device 38 and a speed control device 39. In addition,
The power supply inverter 37 converts the power from the power supply 40 into a predetermined frequency and phase, a voltage, a current, or the like, and supplies the same to the linear reluctance motor 19.

Further, the control rod position control device 38 causes the control rod 1 to be quickly inserted and a position command signal 41 for designating a predetermined position by inserting or extracting the control rod 1 for controlling the output of the reactor. Scrum signal 42 and position detector 20
A position signal 43 indicating the position of the control rod 1 is input to output various control rod information to the speed control device 39 and a latch operation signal 44 for activation and release to the latch mechanism 21.

In the speed control device 39, the power supply inverter 37 is used based on the control rod information from the control rod position control device 38.
The driving rod 18 is driven by a linear reluctance motor 19 to output a speed control signal for performing a control rod operation in a predetermined direction and speed.
12).

Next, the operation of the above configuration will be described. The power supply inverter 37 changes the frequency and phase of the power from the power supply 40 so that the linear reluctance motor 19
Can control the output thrust. Accordingly, the control rod position control device 38 responds to the position command signal 41 of the control rod 1 and the position signal 43 of the control rod 1 from the position detector 20.
Thus, the moving direction and the moving amount of the control rod 1, which are various kinds of control rod information, and the speed corresponding to the moving amount are calculated and output to the speed control device 39.

Thus, the speed control device 39 is connected to the power supply inverter 37 by the drive rod of the linear reluctance motor 19.
A speed control signal for causing the control rod 1 to perform a predetermined operation is output by 18.

Accordingly, the control rod driving mechanisms 16 and 32 can perform the driving for inserting or pulling out the control rod 1 into the core at a predetermined speed and the holding control for stopping the control rod. The linear reluctance motor 19 is driven at a high speed by the scrum signal 42 input to the rod position control device 38, so that the control rod 1 can be rapidly inserted into the reactor core.
Four).

The control rod position control device 38 has a latch mechanism.
On the other hand, when the drive rod 18 moves, the latch mechanism 21 is released when the drive force of the linear reluctance motor 19 exceeds the holding force of the drive rod 18 to which the control rod 1 is connected. Further, when the drive rod 18 reaches a predetermined position and stops, and when the driving force of the drive rod 18 in the linear reluctance motor 19 decreases due to loss of power or the like, the latch mechanism 21 is operated to control the control rod. A latch operation signal 44 for holding the position of 1 is output.

Further, in order to more reliably cope with the scram of the control rod 1 in the reactor, the operation of rapidly inserting the control rod 1 in the reactor scram is driven by the linear reluctance motor 19 and the water injection pipe 31. By injecting the scrum water 11 more, the one in which the control rod 1 is rapidly inserted by water pressure is used in combination, and the reliability is improved by using either one as a backup.

As described above, in the power supply inverter 37, which is the drive power supply for the linear reluctance motor 19, the control rod 1 can be inserted into or pulled out of the core at an arbitrary speed by controlling the frequency and phase. Accordingly, rapid power control of the reactor can be easily performed. Further, since the drive source of the linear reluctance motor 19 is electric power, it is easy to operate many control rods 1 at the same time or to operate repeatedly.

Therefore, in response to transient phenomena such as excessive pressure rise and temperature rise of the reactor due to fluctuations in the power of the reactor and fluctuations in the external power supply, and sudden temperature drops, the operation of the control rod 1 is performed quickly and appropriately. By appropriately controlling the reactor power, transient phenomena can be easily mitigated (claim 15).

As shown in the control system block diagram of FIG. 8, the control device of the control rod drive mechanism by the linear reluctance motor 19 is a power supply inverter 37 and a control rod position control device. It comprises a power control inverter 38 and an uninterruptible power supply 47 with a battery -46 connected to the input side of the power supply inverter 37. Since the configuration other than the above is the same as the configuration of the third embodiment described above,
Next, only operations and effects different from those of the third embodiment will be described.

In the control device of the control rod drive mechanisms 16 and 23, since the uninterruptible power supply 47 is connected to the input side of the power supply inverter 37 to which the external power supply 40 is input,
If a power failure or an instantaneous voltage drop occurs in the external power supply system and the power supply 40 is lost or fluctuates, the uninterruptible power supply replaces the power supply 40 via the uninterruptible inverter 45 from the battery 46 of the uninterruptible power supply 47. At power inverter 37
Is supplied with normal power.

Therefore, in the control rod drive mechanisms 16 and 32, not only the operation of the control rod 1 during normal operation due to disturbance of the external power supply system, but also the operation of the reactor without any trouble during scram. Since the safe operation is performed, the reliability in the nuclear power plant is improved.

As shown in the control system block diagram of FIG. 9, the control device of the control rod drive mechanisms 16 and 23 by the linear reluctance motor 19 comprises a power inverter 37 and a control rod. In addition to a position controller 38 and a speed controller 39, an uninterruptible inverter 48, an induction motor 49 and an uninterruptible power supply 51 composed of a flywheel 50 are connected to the input side of the power inverter 37. Since the configuration other than the above is the same as the configuration of the above-described third embodiment, only the functions and effects different from those of the third embodiment will be described below.

In the control device of the control rod driving mechanisms 16 and 23, since the uninterruptible power supply 51 is connected to the input side of the power supply inverter 37 to which the external power supply 40 is input,
When the power supply 40 is lost or a momentary power failure occurs, the rotational energy held by the induction motor 49 and the flywheel 50 supplies normal power to the power supply inverter 37 by the uninterruptible power instead of the power supply 40 via the uninterruptible inverter 48. You. Thus, safe operation of the reactor is performed in the same manner as in the fourth embodiment.

The present invention described above can be easily applied to a fast breeder reactor, and in this case, the same operation and effect as those of the boiling water reactor can be obtained. .

[0083]

As described above, according to the present invention, since the internal structure of the control rod drive mechanism is simple and there is no shaft sealing portion, the frequency of maintenance and inspection is low, and the sealing portion at the bottom of the reactor pressure vessel is formed. Reliability is improved. Also, when disassembling the control rod drive mechanism, the drive rod can be pulled out into the reactor pressure vessel like the control rod, and the linear reluctance motor etc. are drawn out to the lower part of the reactor pressure vessel. The space required for maintenance and inspection at the lower part of the building can be reduced, so that the reactor building can be lowered and the seismic structure can be strengthened.

Further, since the drive of the control rod is directly linear drive and the drive speed can be set arbitrarily from the insertion or withdrawal of the control rod to the insertion of the scrum, the response time can be shortened. Transient phenomena of the reactor plant due to fluctuations in the power of the reactor and fluctuations in the power supply outside the reactor are easily alleviated, and the performance of the reactor plant is improved.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a control rod driving mechanism according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view of a stator of the linear reluctance motor according to the first embodiment of the present invention.

FIG. 3 is a perspective view of a main part of the drive shaft according to the first embodiment of the present invention.

FIG. 4 is a longitudinal sectional view of a latch mechanism and the like according to the first embodiment of the present invention.

FIG. 5 is a longitudinal sectional view of a control rod driving mechanism according to a second embodiment of the present invention.

FIG. 6 is a thrust characteristic curve diagram of a linear reluctance motor.

FIG. 7 is a control system block diagram according to a third embodiment of the present invention.

FIG. 8 is a control system block diagram of a fourth embodiment according to the present invention.

FIG. 9 is a control system block diagram according to a fifth embodiment of the present invention.

FIG. 10 is a longitudinal sectional view of a conventional control rod driving mechanism.

FIG. 11 is a longitudinal sectional view showing an installation relationship between a control rod drive mechanism and a reactor pressure vessel.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Control rod, 2 ... Coupling, 3, 16, 32 ... Control rod drive mechanism, 4 ... Connecting pipe, 5 ... Ball screw, 6 ... Motor coupling, 7 ... Drive motor, 8 ... Ball nut, 9 ... Reactor Pressure vessel, 10… Shaft seal, 11… Scrum water, 12,17…
Control rod drive mechanism housing, 12a: Housing flange, 13: Control rod guide tube, 14: Core, 15: Shaft sealed end plug, 15a
... End plug flange, 18 ... Drive rod, 19, 19a, 19b ... Linear reluctance motor, 20 ... Position detector, 21 ... Latch mechanism, 21a ... Latch mechanism claw, 22 ... Closed end plug, 22a ... Closed end plug flange , 23… stator, 24… stator core, 25,29…
Tooth profile, 26 ... stator coil, 27 ... can, 28 ... resin mold, 30 ... groove, 31 ... water injection pipe, 33 ... thrust curve of one motor,
34 ... Thrust force curve of one motor with shifted tooth profile relative position, 35
... Total thrust curve of two motors whose tooth profile relative positions are not shifted, 36 ... Total thrust curve of two motors whose tooth shape relative positions are shifted, 37 ... Power inverter, 38 ... Control rod position control device,
39: speed controller, 40: power supply, 41: position command signal, 42:
Scrum command signal, 43 position signal, 44 latch operation signal, 45, 48 uninterruptible inverter, 46 battery, 47
51: uninterruptible power supply, 49: induction motor, 50: flywheel, A: total minimum thrust value when the relative position of the tooth profile is not shifted, B: total minimum thrust value when the relative position of the tooth profile is shifted.

Continued on the front page (72) Inventor Buntoku Ishibashi 2121 Naoyo, Asahi-machi, Mie-gun, Mie Prefecture Inside Mie Plant, Toshiba Corporation (72) Inventor Hideo Komita 8 Shinsugita-cho, Isogo-ku, Yokohama-shi, Kanagawa Prefecture Toshiba Yokohama Corporation In business office

Claims (16)

[Claims] 1. A control rod drive mechanism which is installed through a reactor pressure vessel and inserts or withdraws a control rod into a reactor core, wherein an upper part is fixed to the reactor pressure vessel and a lower part is a closed end plug. A sealed control rod drive mechanism housing, a drive shaft having a tooth profile formed on the outer periphery that moves up and down in connection with the control rod in the reactor pressure vessel, and a stator that movably drives the drive shaft A linear reluctance motor including a stator core and a stator coil having teeth formed on the inner periphery of the motor; a latch mechanism for retaining the control rod by engaging with the teeth of the drive shaft; and attaching to the teeth or teeth of the drive shaft. A control rod drive mechanism provided with a position detector for detecting an insertion position of the control rod using a magnet or the like. 2. The control rod drive mechanism according to claim 1, wherein the linear reluctance motor is an underwater motor installed underwater in a control rod drive mechanism housing. 3. The control rod driving mechanism according to claim 2, wherein the linear reluctance motor as the underwater motor is a cand type in which a stator core of a stator and a stator coil are watertightly surrounded by a can. . 4. The control rod drive mechanism according to claim 2, wherein the linear reluctance motor as the underwater motor has a stator core and a stator coil of a stator molded with resin. 5. The linear reluctance motor used as the underwater motor is a cand type in which a stator core and a stator coil of a stator are molded with resin and water-tightly surrounded by a can. Control rod drive mechanism. 6. The control rod drive mechanism according to claim 1, wherein scram water is injected into the control rod drive mechanism housing, and the control rod is rapidly inserted into the furnace through the drive shaft by water pressure. 2. The control rod drive mechanism device according to claim 1. 7. The control rod drive mechanism, wherein a drive shaft can be pulled out of the control rod drive mechanism housing to the upper part of the reactor pressure vessel, and the stator, the position detector, and the latch mechanism are integrally or separately formed. The control rod drive mechanism according to claim 1, wherein the control rod drive mechanism can be pulled out from a lower part of the furnace pressure vessel. 8. The linear reluctance motor is characterized in that a plurality of linear reluctance motors are installed coaxially and the relative positions of the tooth profile of the drive shaft and the tooth profile of the stator core of each linear reluctance motor are shifted. The control rod drive mechanism according to claim 1. 9. The control rod driving mechanism according to claim 1, wherein a plurality of linear reluctance motors are installed coaxially and supply a current having a phase shifted to a stator coil of each linear reluctance motor. . 10. The linear reluctance motor is characterized in that a stator is divided into a plurality in the axial direction, and a relative position between a tooth profile of the drive shaft and a tooth profile of a stator core of each stator is shifted. The control rod drive mechanism according to claim 1, wherein 11. The control according to claim 1, wherein the linear reluctance motor divides a stator coil of the stator into a plurality of pieces in an axial direction and supplies a current having a phase shifted to each stator coil. Rod drive mechanism. 12. A control rod drive mechanism provided with the linear reluctance motor, wherein a power supply inverter for converting power supply power into a predetermined frequency, phase, voltage or current, a control rod position command signal, a scrum signal and a position signal And a speed control device for inputting the control rod information and performing a predetermined control rod operation via the power supply inverter. A control device for a control rod drive mechanism, characterized in that: 13. A control rod driving mechanism having a linear reluctance motor, wherein a drive shaft connected to the control rod is driven by the linear reluctance motor, and a driving speed of the drive shaft is increased by a predetermined control rod insertion or withdrawal speed to insert a scrum. A method of operating a control rod drive mechanism, wherein the power supply frequency of the linear reluctance motor is varied up to a speed. 14. A control rod driving mechanism provided with the linear reluctance motor, wherein a drive shaft is rapidly driven by a linear reluctance motor by input of a scram signal, and a reactor is scrammed by rapid insertion of a control rod. The method of operating a control rod drive mechanism according to claim 13. 15. A control rod drive mechanism provided with the linear reluctance motor, wherein a signal that detects a transient phenomenon occurring in the reactor plant is input to a control device to determine the frequency and phase of power supplied to the linear reluctance motor. Controlling the power of the reactor by quickly inserting or removing the control rod through the drive shaft into or out of the reactor core to avoid excessive pressure rise, temperature rise or sudden temperature drop of the reactor Operation method of control rod drive mechanism. 16. The control device according to claim 1, wherein an uninterruptible power supply including a battery and an uninterruptible inverter, or an uninterruptible power supply including a flywheel, an induction motor, and an uninterruptible inverter is provided on a power input side of the power inverter. The control device for a control rod drive mechanism according to claim 12.