JPH0980182A - Reactor control rod controller - Google Patents

Abstract

(57) [Summary] [Object] The present invention provides an atom in which electromagnetic noise generated by driving a motor does not affect the neutron instrumentation system when the control rod needs to be operated with the motor as a drive source. A furnace control rod controller is provided. [Constitution] The control rods 9A to 9N are driven by induction motors 7A to 7N. The electromagnetic brakes 13A to 13N are provided on the induction motors 7A to 7N. The control rod control device 1 controls the control rod position based on the control rod operation sequence. The output signal of the control rod control device 1 is a control rod drive circuit 4A.
.About.4N, the switching circuits 6A to 6N and 12A to 12N are turned on through the electromagnetic brake drive circuits 10A to 10N.
Turn off. The position of the control rod is controlled by this, but the control rod drive source is controlled by on / off control using an induction motor equipped with an electromagnetic brake.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control rod control device for a nuclear reactor which monitors neutrons in the nuclear reactor to operate the nuclear reactor.

[0002]

2. Description of the Related Art Conventionally, a hydraulic drive source has been used as a drive source for a control rod for controlling the output of a nuclear reactor. However,
In recent years, it has been required to finely finely adjust the reactor power output by the control rod. It is difficult to make fine adjustments with a water pressure drive source, and it has been proposed to use a step motor as a control rod drive source, and it has been developed for practical use. The step motor is controlled by a power converter that is composed of a forward converter and an inverse converter and outputs a voltage of a variable frequency variable voltage. By controlling the power converter, fine adjustment of the control rod position is possible. .

On the other hand, when operating a nuclear reactor, neutron flux is detected in order to monitor the core state. The neutron instrumentation system includes a neutron source monitor (SRM), an intermediate region monitor (IRM) and an output region monitor (PRM). The SRM counts the output pulse of the neutron detector, and the IRM is 2 of the AC output current of the neutron detector.
The PRM measures the mean value of the neutrons, and the PRM measures the level of the DC output current of the neutron detector. By providing these three monitors, the neutron flux (reactor output) can be monitored in a wide range. In the next-generation nuclear reactor, it has been attempted to use a start-up area monitor (SRNM) in which SRM and IRM are integrated, and the product has been developed. Functionally SRM and IR in SRNM
It has both functions.

[0004]

In the boiling water reactor, in order to take out the fuel assembly and the control rods from the reactor, the upper lid of the pressure vessel is opened and the fuel vessel is taken out from the upper portion of the pressure vessel. For this reason, the control rod drive source is installed below the pressure vessel. In addition, the reactor neutron flux is required to be constantly measured, including when the fuel assembly is replaced. For this reason, in the neutron instrumentation system, the detection signal of the neutron detector is transmitted to the main control room by a signal cable routed below the pressure vessel.

By the way, when the control rod is driven by the step motor, since the switching element of the power converter is turned on and off, high frequency electromagnetic noise is generated due to the wiring inductance and stray capacitance. This electromagnetic noise (high-frequency noise) is assumed to be 3 phases in the power converter (inverse converter) and the output frequency changes between 5.5 Hz and 50 Hz.
It occurs at intervals of 0 ms to 3.3 ms. Then, when the reactor is started, the control rods are continuously withdrawn from all insertion positions to all withdrawal positions. The time is about 120 seconds, and a huge number of high frequency noises are generated during the control rod driving period.
This high-frequency noise may affect the neutron instrumentation system, resulting in inaccurate monitoring of reactor power and reactor cycle.

It is an object of the present invention to provide a control rod control device for a nuclear reactor which can drive the control rods without affecting the monitoring of the neutron instrumentation system.

[0007]

SUMMARY OF THE INVENTION The present invention resides in that a control rod is driven by an induction motor equipped with an electromagnetic brake and controlled to be turned on and off.

[0008]

[Function] Since the induction motor is controlled to be turned on and off, electromagnetic noise is generated only when the neutron instrumentation system is turned on and off, and even if the neutron instrumentation system is miscounted, it does not affect the neutron instrumentation system. Can be done accurately.

[0009]

FIG. 1 shows an embodiment of the present invention.

In FIG. 1, a large number of control rods 9A to 9N are arranged in a reactor pressure vessel 14. Control rod 9A
Although about 9N depends on the type of the reactor plant and the power generation capacity, about 200 N are arranged. The control rods 9A to 9N are adjusted in vertical position by the induction motors 7A to 7N provided in the lower portion of the pressure vessel 14. Induction motor 7A-7N
Are provided with electromagnetic brakes 13A to 13N, respectively. The electromagnetic brakes 7A-7N are induction motors 7A-7N.
Is stopped and the control rods 9A to 9N are held at predetermined positions. As the electromagnetic brakes 13A to 13N, those of direct current excitation or alternating current excitation are used, and the brakes are released when they are not excited. The induction motors 7A to 7N are switching circuits 6
It is connected to the AC power supply 15 via A to 6N and is turned on and off by turning on and off the switching circuits 6A to 6N. The electromagnetic brakes 13A to 13N are connected to the drive power supply 16 via the switching circuits 12A to 12N. The positions of the control rods 9A to 9N are detected by the corresponding position detectors 8A to 8N, and their position detection signals 3
Is input to the control rod control device 1. Position detectors 8A-8
As N, a transmitter is used as a sink that converts the amount of rotation of the induction motors 7A to 7N into linear momentum and relatively detects the position. The control rod control device 1 has a control rod operation sequence in which the number of control rods to be operated and the operation amount (drawing amount and insertion amount) are determined, and an operation command (pulling command or insertion command) is issued from an output control device (not shown). When given, a control signal is output to the control rods 9A to 9N determined by the control rod operation sequence. The control signals of the control rod control device 1 are control rod drive circuits 4A-4N and electromagnetic brake drive circuits 10A-10.
N. The control rod drive circuits 4A to 4N output a drive control signal 22 for turning on the switching circuits 6A to 6N which receive the control signal, and the electromagnetic brake drive circuit 1
0A to 10N are switching circuits 1 for inputting control signals
The drive signal 23 for turning off 2A to 12N is output.

FIG. 2 is a schematic configuration diagram of an embodiment of the present invention showing the positional relationship between the control rod control system and the neutron instrumentation system.

FIG. 2 shows a control rod 9i, a neutron detector 1
Only one 7j is shown. A power cable 19i for supplying power to the induction motor 7i and the electromagnetic brake 13i provided under the pressure vessel 14 is connected to the AC power source 15 or the driving power source 16 through the storage vessel 20 and the switching circuit 6i or 12i. In addition, the neutron detector 17
The signal cable 18j for transmitting the detection signal of j passes from the lower portion of the pressure vessel 14 to the containment vessel 20 and the neutron measuring device 2
1j is connected. The power cable 19i and the signal cable 18i are close to each other in the lower section L of the pressure vessel 14. The power supply of the neutron measuring device 21j is obtained from the AC power supply 15.

Next, the operation will be described with reference to the flow chart shown in FIG.

At the time of starting the reactor, the control rod is mainly withdrawn, and the withdrawal operation will be described.

First, the control rod operation sequence of the control rod control device 1 will be described with reference to FIG.

A large number of control rods are provided as shown in FIG.
They are divided into two groups and are located at the coordinate numbers shown. The control rod operation sequence is information about which control rod group is driven to which position (control rod operation limit) in what order and in what operation pattern. In FIG. 4A, first, the control rod group having the control rod group number 1 is continuously withdrawn from the completely inserted position (position 48) to the position 18. The control rod group of the control rod group number 1 is composed of a total of 24 control rods as shown in the control rod coordinates in FIG. In the next operation, the same control rod group is pulled out to the position 22 by step pulling. The other group numbers 2 to M are also predetermined as shown in FIG.

The control rod control device 1 operates in step S1 from the output control device (not shown) to give an operation command (pull-out command) 2
Is input, in step S2, the control rod group number to be operated is recognized and determined based on the control rod operation sequence information shown in FIG. In this case, control rod group number 1 is determined. When the control rod group number is determined, the process proceeds to step S3, and control signals are added to the control rod drive circuits 4A to 4N and the electromagnetic brake drive circuits 10A to 10N of the control rod 9 belonging to the group number 1. The control rod drive circuit 4 belonging to the group number 1 outputs the drive control signal 22 as shown in FIG.
6N is turned on, and electromagnetic brake drive circuits 10A-1
0N outputs the drive signal 23 to turn off the switching circuits 12A to 12N as shown in FIG. 5 (b). It is practically desirable that the OFF operation of the switching circuits 12A to 12N be slightly earlier than the ON operation of the switching circuits 6A to 6N. When the switching circuits 12A to 12N are turned off, the braking operation of the electromagnetic brakes 13A to 13N is released, and when the switching circuits 6A to 6N are turned on, the induction motors 7A to 7N are driven in the direction of pulling out the control rods 9A to 9N. The rotation speeds of the induction motors 7A to 7N are shown in FIG.
become that way. In this way, the pulling-out operation of the control rods 9A to 9N is performed. The control rod control device 1 inputs the position detection signal 3 from the position detectors 8A to 8N of the control rods 9A to 9N for which the pulling operation is performed in step S4, and the position detection signal 3 is input to the position detection signal 3 in step S5 in FIG. ), It is determined whether or not the control rod operation limit (target position) determined by the control rod operation sequence is reached. Step S
If the determination at 5 is NO, the process returns to step S4, and if YES, the process proceeds to step S6. In step S6, the induction motors 7A to 7N are stopped and the electromagnetic brakes 13A to 1N are stopped.
The output of the control signal is stopped to operate the 3N. When the control signal disappears, the control rod drive circuits 4A to 4N turn off the switching circuits 6A to 6N to turn the induction motors 7A to 7N.
And the electromagnetic brake drive circuits 10A-10
N turns on the switching circuits 12A to 12N to operate the electromagnetic brakes 13A to 13N. By this operation, the induction motors 7A to 7N are stopped as shown in FIG. 5C, and the pulling-out operation in the first stage of the control rod group of group number 1 is completed. An output control device (not shown) even after the pulling-out operation in the first stage of the control rod group with the control rod group number 1 is completed.
When an operation command (pull-out command) 2 is given from FIG.
According to the control rod operation sequence shown in (a), the control rod group of the control rod group number 2 is selected and the pull-out operation is executed in the same manner.

If the control rod overruns without stopping at the target position due to inertia of the induction motor when the pulling operation is stopped in step S6, the target position in step S5 is determined by the control rod operating sequence. It is possible to accurately stop at the target position by moving the control rod operation limit forward by an overrun amount. This can be easily done because the overrun amount is almost constant depending on the operation pattern of the control rod (continuous drawing or step drawing).

Although the control rod is operated as described above, the fact that electromagnetic noise does not affect the neutron instrumentation system will be described in comparison with the prior art.

FIG. 6 shows current waveforms of the induction motor 7 and the electromagnetic brake 13. The electromagnetic brake 13 is shown both in the case of a direct current electromagnetic brake and in the case of an alternating current electromagnetic brake.

As described above, in the present invention, the induction motors 7A to 7N and the electromagnetic brakes 13A to 13N are operated by the on / off control, and while the control rod is being driven, as shown in FIG.
As shown in (a), a voltage having a commercial frequency is applied from the AC power source 15 to the induction motors 7A to 7N, and the electromagnetic brake 13A is applied.
For 13N, the excitation is released in this period as shown in FIGS. 6 (b) and 6 (c). Induction motors 7A-7N
Occurs at the start of start and stop before the inrush current flows, and occurs at the start of brake release and at the start of brake operation for the electromagnetic brakes 13A to 13N. This electromagnetic noise is high-frequency electromagnetic noise that is determined by the inductance and stray capacitance of the wiring and the switching speed of the switching circuit 6.

As described above, in the present invention, the electromagnetic noise is generated twice before the control rod operation is started and when it is stopped.
On the other hand, in the case of the step motor, high-frequency electromagnetic noise is generated every time the power converter performs the switching operation, which is also continuously generated during the operation of the control rod.

By the way, the neutron instrumentation system of a nuclear reactor is equipped with three types of monitors: a neutron source region monitor (SRM), an intermediate region monitor (IRM) and an output region monitor (PRM). SRM is a monitor that counts the output pulses of the neutron detector, IRM is a monitor that measures the root mean square of the AC signal that is the output current of the neutron detector, and PRM is the DC that is the output current of the neutron detector. It is a monitor that measures the signal level. The measurement range of these monitors is, for example, as shown in FIG. 7, and a wide range of measurement is required.

At the start of plant startup, the control rods are pulled out to increase the furnace output, but the control rods are pulled out in both the SRM and IRM measurement ranges of FIG. 7. One of the important things in operation management at the time of plant startup is to perform criticality judgment correctly. The criticality judgment is made based on the value of the reactor cycle (period) which is one output of the SRM. The furnace cycle is output based on the pulse count rate counted by the SRM. The shorter furnace cycle means that the furnace output per unit time is increasing. When electromagnetic noise is mixed into the SRM and the pulse count rate per unit time increases, the furnace cycle becomes shorter. As for the timing of criticality judgment, the reactor power in Fig. 7 is 10 ^-4 %.
It is about the same time (about 10 ⁵ pieces / second), which is shown in FIG.
This corresponds to the middle of pulling out the control rod group having the control rod group number 3 in the operation sequence shown in FIG. Therefore, in the type in which the control rod is driven by the step motor, electromagnetic noise is generated while pulling out the control rod, so that the electromagnetic noise is mixed into the SRM to increase the pulse count rate,
It shortens the furnace cycle. As a result, there is a possibility that the criticality judgment cannot be correctly judged. When driving the control rod by on / off control using an induction motor,
Since electromagnetic noise does not occur while pulling out the control rod, S
Since the pulsed neutron count rate of the RM does not affect, the correct furnace cycle can be output from the SRM, and the criticality judgment can be performed correctly. Also, the number of pulses of electromagnetic noise generated when starting and stopping the control rod drive is several,
It is sufficiently smaller than the above-mentioned 10 ⁵ pieces / second, and its effect is so small that it does not pose a problem.

Particularly, when the control rod is driven (pulled out) when the furnace output is low and the SRM count rate is several tens / second, several thousand electromagnetic noises are generated immediately after the motor is started in the case of the step motor. Therefore, there is a possibility that the counting rate per unit time rises and the furnace cycle becomes short, leading to scram, but the present invention has no effect.

Further, in the IRM, the root mean square of the output signal of the neutron detector is measured, and when this value exceeds a predetermined value, scrum is performed from the standpoint of plant operation management. Therefore, when a stepper motor is used, I
There is a possibility that the output value (root mean square value) of the RM becomes high and unnecessary scrum occurs. Even in SRM,
When the stepping motor is used, the scram may be reached in the same manner because the scram is designed to be performed when the furnace cycle becomes equal to or less than the predetermined value.

Recently, a start-up area monitor (SRNM) in which an SRM and an IRM are integrated has been developed. In this SRNM as well, as in the SRM and IRM, a pulse counting mode and an AC signal 2 are used. There is a mode for measuring the weighted average, and the effect can be eliminated by the present invention.

As described above, according to the present invention, since electromagnetic noise is generated only when the induction motor is started and stopped, the frequency of occurrence of electromagnetic noise per control rod operation is sufficiently low, and the neutron instrumentation system due to electromagnetic noise is not generated. The influence can be suppressed sufficiently.

FIG. 8 shows another embodiment of the present invention.

8 is different from FIG. 1 in that the delay circuits 5A to 5N delay the drive control signal 22 of the control rod drive circuits 4A to 4N (timing adjustment) and the drive signal 23 of the electromagnetic brake drive circuits 10A to 10N. The delay circuits 11A to 11N for delaying (timing adjustment) are provided.

FIG. 9 shows a processing flow of the control rod control device 1 in the embodiment of FIG. 9 is different from FIG. 3 in that steps S7 and S8 are added. In step S7, the control rod group with one control rod group number is divided into a plurality. The dividing method will be described later. In step S9, the delay time setting signal 17 is output to the delay circuit corresponding to the divided control rod group. Control rod group number recognized in step S2 (1 in this case)
The control signal is output to the control rod of. This control signal is applied to the control rod drive circuits 4A to 4N and the electromagnetic brake drive circuit 10.
Input to A to 10N. As a result, the control rod drive circuit 4
The drive signals for driving (pulling out in this case) the control rod are output from A to 4N, and the brake release signal for releasing the brake operation is output from the electromagnetic brake drive circuits 10A to 10N. These signals are output to the switching circuits 6A to 6N and 12A to 12N after a predetermined time (different for each divided control rod group) has elapsed by the delay circuits 5A to 5N and 11A to 11N. The switching circuit rotates the induction motors 7A to 7N in accordance with these signals and releases the braking operation of the electromagnetic brakes 13A to 13N. The following processing (steps S3 to S6) is the same as that in FIG. Control rod group number 1
FIG. 10 shows a time chart obtained by dividing n into n.

An example of a control rod group obtained by dividing the control rod group number 1 is shown in FIG. In this figure, the number of divisions is a group of four control rods surrounded by double circles, single circles, triangles, and squares. When dividing, it is desirable that the reactivity value of the control rod does not differ from the value calculated in advance (the value designed so that the reactivity values of all the control rods are almost equal). When the control rod group number 1 is divided into four as shown in FIG. 11, for example, the control rod group is pulled out by shifting the time in the order of double circle, single circle, triangle, and square. In this example, the six control rods move simultaneously, but since the reactivity values of the control rods are selected to be almost equal, these six control rods are all concentrated at the local position. Rather than scattered throughout the core. Therefore, the high frequency noise generated when the six control rods are driven at the same time is generated at physically different positions (because the disposition of the power cable 19 is different) and is induced by the neutron detection cable 18. Noise does not occur at the same time. The positional relationship between the power cable 19 and the neutron detection cable 18 is as shown in FIG. 2, and both cables are closest to each other under the reactor pressure vessel 14,
Electromagnetic noise generated when the induction motor 7 and the electromagnetic brake 13 are operated is induced in the neutron detector cable 18 via the power cable 19 at this portion. However, since the induction motors 7 that are activated at the same time are scattered, the influence is small. As a result, the control rod group number is subdivided into a plurality of control rod groups, and the subdivided control rod groups are driven at different times, so that the generated electromagnetic noise is scattered both temporally and physically. The influence on the neutron instrumentation system is suppressed.

As described above, by providing the delay circuits 5A to 5N and 11A to 11N as in the embodiment shown in FIG. 8 and adjusting the timing, the influence of electromagnetic noise generated during control rod operation on the neutron instrumentation system is affected. It is possible to further suppress it.

In the embodiment of FIG. 8, the delay circuits 5A-5
N, 11A to 11N are switching circuits 6A to 6N, 1
2A to 12N are provided between the control rod drive circuits 4A to 4N and the electromagnetic brake drive circuits 10A to 10N, but these are provided between the control rod drive circuits 4A to 4N and the electromagnetic brake drive circuit 1.
As a matter of course, it may be provided before 0A to 10N. Also, the functions of the delay circuits 5A to 5N and 11A to 11N can be incorporated in the processing of the control rod control device 1 to perform the same operation. In this case, instead of outputting the delay time setting signal 17 in step S8 of FIG. 9, it is possible to perform time management for executing step S3 after a predetermined delay time.

Next, in the embodiment shown in FIG. 8, the induction motor 7
Starting and stopping of A to 7N and electromagnetic brakes 13A to 13N
It is also possible to equivalently suppress the level of electromagnetic noise affecting the neutron instrumentation system by shifting the brake release and brake start operation timings. Specifically, this can be achieved by shifting the delay times of the delay circuits 5A to 5N for the induction motors 7A to 7N and the delay circuits 11A to 11N for the electromagnetic brakes 13A to 13N. The delay time must be at least longer than the electromagnetic noise generation period. The processing flow of the control rod control device 1 for this purpose is shown in FIG.
Shown in FIG. 12 shows a process in the case where a plurality of control rods are further divided into small groups and driven. In step S9, a delay time setting signal 17 indicating the delay time of the electromagnetic brake 13 with respect to the induction motor 7 is output to the delay circuit. When the response of the electromagnetic brake 13 is slow, it is necessary to release the brake of the electromagnetic brake 13 and start the brake earlier than the start and stop of the induction motor 7, and the delay time is set so that the induction motor 7 operates later than the electromagnetic brake. do it. In addition, the time may be set such that the brake release of the electromagnetic brake is delayed when the induction motor is started, and the brake is started earlier when the induction motor is stopped, or vice versa. In any case, the operation timings of the induction motor 7 and the electromagnetic brake 13 are shifted.

As described above, by using the induction motor and the electromagnetic brake and shifting the operation start time, the generation timing of the generated electromagnetic noise is deviated, and the level of the electromagnetic noise affecting the neutron instrumentation system is equivalent. Suppressed. As a result, it is possible to suppress the influence of electromagnetic noise on the neutron instrumentation system.

[0037]

EFFECTS OF THE INVENTION A control rod is operated by using an induction motor equipped with an electromagnetic brake as a drive source, and the induction motor and the electromagnetic brake are driven by on / off control, thereby switching the induction motor and the electromagnetic brake. The element can remain on or off during control rod operation so that no electromagnetic noise is generated during control rod operation. Therefore, the neutron instrumentation system is not affected by electromagnetic noise when the control rod is operated, and the neutron instrumentation system can be accurately monitored.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of the present invention.

FIG. 2 is a configuration diagram showing an arrangement of a part of FIG.

FIG. 3 is a processing flowchart for explaining the operation.

FIG. 4 is a diagram showing an example of a control rod operation sequence and control rod group numbers.

FIG. 5 is a waveform chart for explaining the operation.

FIG. 6 is a waveform diagram showing an electromagnetic noise generation timing.

FIG. 7 is an explanatory diagram of a measurement range of a neutron instrumentation system.

FIG. 8 is a configuration diagram showing another embodiment of the present invention.

9 is a process flow chart for explaining the operation of the embodiment shown in FIG.

10 is a waveform diagram for explaining the operation of the embodiment shown in FIG.

FIG. 11 is a diagram showing a divided arrangement of control rod groups.

FIG. 12 is a flowchart of another operation explanation process of the embodiment shown in FIG.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Control rod control device, 5A-5N, 11A-11N ... Delay circuit, 7A-7N ... Induction motor, 9A-9N ... Control rod, 13A-13N ... Electromagnetic brake.

Claims (6)

[Claims] 1. A control rod for controlling the output of a nuclear reactor, a neutron instrumentation device for detecting neutrons in the nuclear reactor and transmitting the neutrons from a lower portion of the nuclear reactor pressure vessel, and a lower portion of the nuclear reactor pressure vessel. An induction motor that drives the control rod, and an electromagnetic brake that brakes and stops the induction motor,
A control rod control device for a nuclear reactor, comprising: the induction motor; and a control rod control means for controlling on / off of power supply to the electromagnetic brake. 2. A control rod for controlling the output of the reactor, a neutron instrumentation device for transmitting a neutron detection signal in the reactor from the lower part of the reactor pressure vessel by a signal cable, and a lower part of the reactor pressure vessel. An induction motor that is provided to adjust the position of the control rod, an electromagnetic brake that holds the control rod at that position by braking the induction motor to stop it, and a position detector that detects the position of the control rod. , A control of a nuclear reactor comprising a control rod control means for inputting a position signal detected by the position detector and controlling ON / OFF of the electric power supply to the induction motor and the electromagnetic brake based on a predetermined control rod operation sequence Rod control device. 3. A control rod for controlling the output of the reactor, a neutron instrumentation device for transmitting a neutron detection signal in the reactor from a lower portion of the reactor pressure vessel by a signal cable, and a lower portion of the reactor pressure vessel. An induction motor that is provided to adjust the position of the control rod, an electromagnetic brake that holds the control rod at that position by braking the induction motor to stop it, and a position detector that detects the position of the control rod. The control rod control means for inputting the position signal detected by the position detector and controlling the power supply to the induction motor and the electromagnetic brake based on a predetermined control rod operation sequence, and the control rod control means. A control rod control device for a nuclear reactor, comprising: the induction motor to be controlled; and timing adjusting means for varying on / off timings of the electromagnetic brake. 4. A control rod for controlling the output of the reactor, a neutron instrumentation device for transmitting a neutron detection signal in the reactor from the lower part of the reactor pressure vessel by a signal cable, and a lower part of the reactor pressure vessel. An induction motor for adjusting the position of the control rod, an electromagnetic brake for braking the induction motor to stop the induction motor, and a first power cable for connecting the induction motor to an AC power source. A switching device, a second switching device provided on a second power cable connecting the electromagnetic brake to a drive power source, a position detector for detecting the position of the control rod, and a position detected by the position detector. A control rod of a nuclear reactor comprising a control rod control means for inputting a signal and turning on and off the first and second switching devices based on a predetermined control rod operation sequence. Control device. 5. A plurality of control rods for controlling the output of a nuclear reactor, a neutron instrumentation device for transmitting a neutron detection signal in the nuclear reactor from a lower portion of the nuclear reactor pressure vessel by a signal cable, and the nuclear reactor pressure vessel. A plurality of induction motors, each of which is provided in the lower part of the
An electromagnetic brake provided on each of the multiple induction motors, a position detector that detects the position of each of the multiple control rods, and a position signal detected by the position detector are input, and a predetermined control rod is input. A control rod control device for a nuclear reactor, comprising: a plurality of the induction motors forming one group determined by an operation sequence; and control rod control means for controlling ON / OFF of power supply to the electromagnetic brake. 6. A large number of control rods for controlling the output of a nuclear reactor, a neutron instrumentation device for transmitting a neutron detection signal in the nuclear reactor from a lower portion of the nuclear reactor pressure vessel by a signal cable, and the nuclear reactor pressure vessel. A plurality of induction motors, each of which is provided in the lower part of the
An electromagnetic brake provided on each of the multiple induction motors, a position detector that detects the position of each of the multiple control rods, and a position signal detected by the position detector are input, and a predetermined control rod is input. Control rod control means for on / off controlling power supply to the plurality of induction motors and the electromagnetic brake of one group determined by an operation sequence;
A control rod control device for a nuclear reactor, comprising: a plurality of induction motors controlled by the control rod control means; and timing adjusting means for varying on / off timings of electromagnetic brakes.