JPS5973793A - Control rod drive mechanism - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a control rod drive device, and particularly to a control rod drive device suitable for controlling the drive of nuclear reactor control rods.

[Prior art]

When operating a nuclear reactor with I118 control rods, the control I11 rods are pulled out of the reactor core during the reactor startup process.
During the shutdown process, control rods must be inserted into the reactor core.

Hydraulic drive or electric motor drive has conventionally been used as the power for moving this solid control rod.

FIG. 1 shows the configuration of a conventional control rod drive device driven by an electric motor.

In FIG. 1, a plurality of control rods 2 installed in a nuclear reactor 1 are moved up and down by a drive motor 3. As shown in FIG.

, the drive motor 3 has a selection contactor 4 and an operation contactor 5A.

It is driven based on the operation of 5B.

The selection contactor 4 and the operation contactors 5A and 5B operate based on commands from the command unit 6. The command section 6 is composed of an operation circuit 7 and a selection circuit 8. Operation circuit 7 based on operation
When the withdrawal command 100 is outputted from , the operation contactor 5A is activated, and when the insertion command 102 is outputted, the operation contactor 5B is activated. Further, when a selection command 104 for selecting one of the control rods 2 is output from the selection circuit 8, the selection contactor 4 corresponding to this selection command 104 is activated. Then, the operation of the operation contactors 5A, 5B and the selection contactor 4 closes a drive loop for driving the control unit 2 to be pulled out or inserted.

Further, a monitor circuit 9 is provided for monitoring the operating state of the reactor 1, and when the operating state of the reactor 1 deviates from the normal operating state, a withdrawal prevention signal 106 is sent from the monitor circuit 9 to the operating circuit. 7. Extraction prevention signal 1
06 is supplied to the operation circuit 7, the withdrawal command 100 from the operation circuit 7 is stopped, and the drive loop of the drive motor 3 caused by the operation of the operation contactor 5A is interrupted.

In this way, the conventional control rod drive device W can insert or withdraw the control rod 2 based on a command, and
Since the withdrawal drive of the control rods 2 can be stopped, even if the reactor deviates from the normal operating state, it is possible to prevent the reactor from becoming overpowered.

However, if a sticking failure occurs in the operating contactor 5A,
Removal command 10 when reactor 1 deviates from normal operating state
Even if 0 is stopped, the extraction drive of the mi'J control rod 2 continues, and the operation of the nuclear reactor 1 shifts to the direction of the withdrawal force. As a result, the safety protection system of the reactor 1 is activated and the reactor 1 is brought to an emergency shutdown.

In this way, with conventional equipment, if the drive command system that commands the drive of the control rods fails, the reactor operation is stopped when the operating state of the reactor deviates from the normal operating state, and the operating rate of the reactor is reduced. The disadvantage was that it decreased.

[Purpose of the invention]

The present invention has been made in view of the above-mentioned conventional problems, and its purpose is to improve the operating rate of a nuclear reactor even if a failure occurs in the drive command system that commands the drive of the nuclear reactor. An object of the present invention is to provide a control rod drive device.

[Summary of the invention]

The present invention is a system different from the drive command system that commands the drive of control rods when the operation of the nuclear reactor is interrupted from the normal operating state.
It is characterized by providing a drive loop cutoff system that cuts off the drive loop that drives the control rods.

[Embodiments of the invention]

Hereinafter, preferred embodiments of the present invention will be described based on the drawings.

FIG. 2 shows the configuration of a preferred embodiment of the invention.

The device in this embodiment has pull-out prevention contactors 20 and 8 20B inserted into the drive loop of the control rod 2 of the device shown in FIG. The rest of the structure is the same as that shown in FIG. 1. Although the drive motor 3 is driven by a three-phase power source, the drive loop is shown in a single line diagram in the figure.

The monitor circuits 10A and IOB supply a withdrawal prevention signal 106 to the operating circuit 7 when the operating state of the nuclear reactor 1 deviates from the normal operating state, and also supplies this withdrawal prevention signal 106 to the withdrawal prevention contactors 20A and 20B. The withdrawal prevention contactors 20A, 20B are activated to interrupt the drive loop driving the control rod 2 by the withdrawal prevention signal 106.

As shown in the sequence configuration of the operating circuit 7 in FIG. 3, the operation contactors 5A and 5B are turned on when the pull-out command is output by the operation of the switch 30 and the relay X is energized. When the insertion command is output by operating the switch 32 and the relay Y is energized, the operation contactor 5B is turned on. When the operation contactor 5A is turned on based on the operation of the switch 30, the monitor circuit 1
When the withdrawal prevention signal 106 is output from 0Δ, 10B, the switches 34 and 36 are turned off, and the operation contactor 5A is turned off.

Further, detection of whether the operating state of the nuclear reactor has deviated from the normal operating state is performed by the monitor circuits 10A and IOB detecting the following states.

(a) When the neutron detection device that measures reactor power is inoperable.

(b) A state in which the reactor output is greater than the standard output.

(C) A state in which the rate of increase in reactor output is greater than the standard value.

and a monitor circuit 10 that detects the states (a) to (C).
A, IOB is configured as shown in FIG. That is, in the state (a) above, the monitor circuit 42 monitors L when the neutron detection device 40 is in an inoperable state (defective plug-in, abnormality in the d source, etc.), and when the state (a) is detected, the monitor circuit 42 From neutron detection device inoperation signal 11
Outputs 0.

In the state (b) above, the reactor output signal is compared with a specified value by the comparator 44, and if the reactor output is greater than the specified value, the comparator 44 outputs a reactor output high signal 112.

The state of (C) above is the reactor output increase monitor circuit 46.
The comparator 48 compares the increase rate with a specified value, and if the rate of increase in the reactor power exceeds the specified value, the comparator 48 outputs a reactor power increase signal 114.

The V-Z is activated when the circuit is interrupted by any one of the signals 110, 112, and 1140, and outputs the withdrawal prevention signal 106.

Regarding the selection of the first control rod 2, only one control rod 2 is selected by the selection command 104 outputted from the selection circuit 8.

That is, the selection circuit 8 includes selection buttons 50, 52, 54, . . . for selecting the control rod 2, as shown in FIG.
...60 are provided, and by operating these selection buttons, only one arbitrary control rod 2 can be selected. When the selection button 50 is operated, the contact 50a
, 50b are opened, contacts 50b and 50d are closed, and the relay 50A is activated. Next, when the switches 70 and 72 for driving the control rod 2 are closed, the relay 50B is activated.
The contacts 50e and 50f are closed, the selection contactor 4 is turned on, and the control rod 2 corresponding to the selection button 50 is selected. At this time, even if any one of the selection buttons 52 to 60 is operated, the relays 52A and 54A are not activated.

Since the drive circuit of 60A is cut off, the control rod 2 cannot be selected even if these selection buttons are operated.

On the other hand, when the drive command is stopped and switches 70 and 72 are turned off, if any of the selection buttons 52 to 60 is operated, the drive loop of relay 5OA formed by contact 50d of relay 50A is interrupted. Since the contacts 50a and 50c of the selection button 50 are closed, a relay drive circuit for the operated selection button is formed, and the relay corresponding to the selection button is activated.

As described above, in this embodiment, the pull-out prevention contactors 20A and 20B are provided in the drive loop of the drive motor 3,
Pullout prevention signal 1 output from the monitor circuit 10A and IOB when the operating state of the reactor deviates from the normal operating state
06, so that even if the operating state of the nuclear reactor deviates from the normal operating state when the operation contactor 5A is stuck, the operation of the pull-out prevention contactors 20A and 20B will stop the operation. The drive loop of the drive motor 3 is cut off, and the withdrawal drive of the control rod 2 can be stopped.

Further, in this embodiment, the drive loop cutoff system that cuts off the drive loop of the drive motor 3 includes the pull-out prevention contactors 20A and 20.
B. Since it is constructed of a dual system of monitor circuits 10A and 1013, even if any of the drive loop cutoff systems fails, the control rod extraction drive can be reliably stopped.

In the embodiment described above, the drive loop interrupting system is a dual system, but a dual system or more allows the control rod to be completely pulled out and driven. Furthermore, if these configurations are 2 out
Of 3, 2 out of 4'z Which configuration can improve the reliability of the 1 drive loop cutoff system.

〔Effect of the invention〕

As explained above, according to the present invention, when the operating state of the nuclear reactor deviates from the normal operating state, the drive loop that drives the control rods in a system different from the drive command system that commands the drive of the control rods. Since the control rods are shut off, even if the operating state of the reactor deviates from the normal operating state due to a failure of the drive control system, it is possible to reliably stop the movement of the control rods by 1%, improving the operating rate of the reactor. It has the excellent effect of being able to achieve this.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram of a conventional device, FIG. 2112 is a configuration diagram showing an embodiment of the present invention, FIG. 3 is a sequence diagram for explaining the configuration of the operating circuit shown in FIG. 1, and FIG. , FIG. 5 is a block diagram for explaining the structure of the monitor circuit shown in FIG. 2, and FIG. 5 is a sequence diagram for explaining the structure of the selection circuit shown in FIG.

Claims (1)

[Claims] 1. The drive loop of the drive unit that drives the control rods of the nuclear reactor in a linear direction is closed in response to a drive command, the control rods are driven, and the operating state of the reactor is monitored by driving the control rods. In a control rod drive device that stops the drive command when the operating state of the reactor deviates from the normal operating state, when the operating state of the reactor deviates from the normal operating state, the drive command is stopped by a system different from the drive command system. A control rod drive device characterized by having a drive loop cutoff system that cuts off a loop. 2. The control rod drive device according to claim 1, wherein the drive loop cutoff system is multiplexed, and each prefecture cuts off the drive loop independently of each other.