JPH0425516B2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a boiling water nuclear reactor (hereinafter referred to as BWR).
Relating to a nuclear reactor recirculation system control device. [Technical Background of the Invention] Generally, the reactor output of a BWR is determined by the degree of insertion of control rods into the reactor core and the increase/decrease state of the flow rate of cooling water in the reactor core. Reactor output control using control rods is mainly used when starting and stopping the reactor, and increasing and decreasing the cooling water flow rate is mainly used to increase or decrease the reactor output and for long-term fuel combustion auxiliary combustion. Changes in reactor power due to changes in core cooling water flow rate occur through changes in neutron flux due to changes in the amount of voids in the core cooling water, and this neutron flux responds sharply to changes in core cooling water flow rate. Moreover, the amount of overshoot with respect to the set target value is also large. Adjustment of core cooling water flow rate is accomplished by controlling the speed of a variable frequency generator that powers the recirculation pump drive motor. That is, the variable frequency generator is connected to the drive motor via a fluid coupling, and a scoop pipe is inserted into the fluid coupling. By adjusting the position of this scoop tube, the coupling force is changed and the driving force transmitted from the drive motor to the variable frequency generator is adjusted. The variable frequency generator, hydraulic coupling, and drive transmission are collectively referred to as an MG set, and are provided with an MG set speed control system for adjusting the position of the scoop pipe. This M-G set speed control system is composed of a speed control section and a scoop pipe operation section. That is, the speed control unit compares and calculates the speed setting signal and the variable frequency generator speed detection signal, outputs a fluid coupling scoop pipe position request signal so that both signals match, and determines the fluid coupling scoop pipe position. Based on the request signal, the position of the scoop tube is controlled by the scoop tube operating section. [Problems with the background art] According to the above configuration, the M-G set speed control system includes instruments including a large number of electronic components, wiring connecting these instruments, a variable frequency generator speed detector, a scoop tube position detector, etc. It has a complex electrical and mechanical structure, and the probability of failure is relatively high. If the speed of the variable frequency generator changes due to these failures, the core cooling water flow rate will change, which will cause a change in neutron flux, leading to a situation such as emergency reactor shutdown due to high neutron flux. Such unnecessary emergency shutdowns will reduce the reactor's operating efficiency. [Object of the Invention] It is an object of the present invention to prevent failures of components of a control system from leading to variations in the speed of a variable frequency generator, thereby reducing unnecessary output fluctuations due to high neutron flux. It is an object of the present invention to provide a nuclear reactor recirculation system control device that can prevent emergency shutdown of a nuclear reactor and perform stable control. [Summary of the Invention] A nuclear reactor recirculation system control device according to the present invention includes a variable frequency generator that supplies variable frequency power to a recirculation pump drive motor, and a variable frequency generator connected to the variable frequency generator to vary the rotation of the drive motor. a fluid coupling that transmits to the frequency generator; a scoop pipe that is provided on the fluid coupling and adjusts transmission of rotation by the fluid coupling;
a variable frequency generator speed detector that detects the speed of the variable frequency generator; a scoop tube operating section that operates the scoop tube; a speed control section that outputs a position request signal to the scoop tube operating section; A speed setting device provided in the control section to set the speed, a speed setting signal from the speed setting device provided in the speed control section and a speed detection signal from the variable frequency generator speed detector are inputted and compared and calculated. a first deviation calculator that outputs a deviation signal; and a speed controller that is provided in the speed control section and receives the deviation signal from the first deviation calculator and outputs a request signal for the operating rod position of the scoop pipe. a position detector provided in the scoop tube operating section to detect the position of the operating rod of the scoop tube; a position signal from the position detector provided in the scoop tube operating section and a position request signal from the speed controller; a second deviation calculator that inputs, performs a comparison calculation, and outputs a deviation signal; and a second deviation calculator that is provided in the scoop pipe operating section and drives an operating rod of the scoop pipe based on the deviation signal from the second deviation calculator. a first switch inserted between the first deviation calculator and the speed controller; and a drive mechanism that connects the speed controller and the second deviation calculator via the second switch. a position error signal converter provided, a current switch inserted between the second deviation calculator and the drive mechanism, and the first switch and second switch provided in the speed control section. and a control mode selector that selects an operation mode by controlling the opening and closing of the current switch, and a control mode selector that is provided in the speed control section and that responds to the operation rod via the drive mechanism to perform runback when a runback command signal is issued. and a sudden decrease signal generation mechanism that outputs a sudden decrease signal to the first deviation calculator or the second deviation calculator. That is, when operating in the feedback control mode, the control mode selector closes the first switch and the current switch, and opens the second switch. This allows the speed setter, the first
Operation by feedback control is performed through a route connecting the second deviation calculator, the speed controller, the second deviation calculator, and the drive mechanism. There is also a constant hold mode,
That is, when operating with the scoop pipe held constant, the control mode selector opens the first switch and the current switch, and closes the second switch. This causes the scoop tube position to remain fixed and the output signal from the speed controller to remain balanced with the fixed operating rod position. Furthermore, when a runback operation is performed based on a command from the plant, a sudden decrease signal is generated from the sudden decrease signal generation mechanism, thereby closing the first switch and the current switch, and the drive mechanism responds to the sudden decrease signal. A runback is performed. Therefore, most of the reactor operating time is spent selecting the constant hold mode using the control mode selector. When operating in this mode, no signals are input to the drive mechanism, so the rake tube fluctuates, the core cooling water flow rate changes, the output fluctuates, or the neutron There is no need for unnecessary emergency shutdown of the nuclear reactor due to high bundles, highly reliable control can be performed, and the operating rate of the plant can be greatly improved. [Embodiment of the Invention] An embodiment of the present invention will be described with reference to FIGS. 1 and 2. FIG. 1 is a schematic diagram of a nuclear reactor recirculation system control device. Code 1 in the figure is a variable frequency generator (hereinafter referred to as
MG). The MG1 supplies variable frequency power to the pump motor 3 of the recirculation pump 2 to drive the recirculation pump 2. By driving the recirculation pump 2, cooling water is forced to circulate within the reactor core via the piping 2a. A drive motor 5 is connected to the MG 1 via a fluid coupling 4. A scoop pipe 6A is inserted into the fluid coupling 4, and an operating rod 6B is connected to the scoop pipe 6A. By adjusting the position of the scoop pipe 6A in the fluid coupling 4 via this operating rod 6B, the coupling force of the fluid coupling 4 is adjusted, and the coupling force from the drive motor 5 is adjusted.
Adjusts the driving force transmitted to MG1. Further, in the figure , 7 indicates a speed control section, and 8 indicates a scoop pipe operation section. The speed control unit 7 detects the speed of the MG1.
It has a mechanism that inputs the MG speed detection signal 9A from the MG speed detector 9 and outputs the position request signal 7A of the operating rod 6B to the scoop tube operating section 8 , and the scoop tube operating section 8 receives this position request signal. The position of the operating rod 6B is operated based on 7A. In addition, numeral 31 in the figure indicates an automatic voltage control device. The details of the speed control section 7 and the scoop tube operating section 8 are constructed as shown in FIG. Reference numeral 10 in the figure indicates a first deviation calculator. This first
The deviation calculator 10 inputs the speed setting signal set by the speed setter 11, and also inputs the speed detection signal 9A from the MG speed detector 9 to the speed converter 1.
Input via 2. Then, a comparison calculation is made between these two signals and a deviation signal is output to the speed controller 13. This speed controller 13 is connected to the first deviation calculator 10
Based on the deviation signal, a position request signal 7A of the operating rod 6B is output to the second deviation calculator 14 provided in the scoop pipe operating section 8 . The scoop pipe operation section 8 is
The second deviation calculator 14 and a drive mechanism 18 connected to the second deviation calculator 14 via an amplifier 15, a power circuit 16, and a current switch 17.
and a position detector 19 that detects the position of the operating rod 6B and converts the signal. The second deviation calculator 14 inputs the position request signal 7A and also receives the position detection signal from the position detector 19, compares and calculates both signals, and outputs a deviation signal. The output deviation signal is converted into an operation signal by the amplifier 15 and is input to the drive mechanism 18 via the power circuit 16 and the current switch 17. The drive mechanism 18 drives the operating rod 6B to adjust the scoop tube position. The speed setter 11 of the speed control section 7 and the first
A switch 20 is provided between the first deviation calculator 10 and the speed controller 1.
A switch 21 is provided between the speed controller 13 and the speed controller 13, and a switch 22 is provided on the output side of the speed controller 13.
Between the switch 20 and the first deviation calculator 10,
A sudden decrease signal generator 23 is connected via a switch 24 . Similarly, a sudden decrease signal generator 25 is connected to the output side of the switch 22 via a switch 26. Further, a position error signal converter 27 is connected between the switch 21 and the speed controller 13 via a switch 28.
One end of the position error signal converter 27 is connected to the position error signal converter 27, and the other end of the position error signal converter 27 is connected between the second error calculator 14 and the amplifier 15 of the scoop tube operating section 8 . Further, the speed control section 7 is provided with a control mode selector 29. This control mode selector 2
9 allows selection of one of the feedback control mode and constant hold mode. That is, when operating in the feedback control mode, the control mode selector 29 selects the switch 21 and the current switch 1.
7 is closed, and switch 28 is opened. At this time, switches 20 and 22 are closed, and switch 2
4 and 26 are open. As a result, feedback control is performed on the route connecting the speed setter 11, the first deviation calculator 10, the speed controller 13, the second deviation calculator 14, and the drive mechanism 18. Next, when operating in the constant hold mode, the control mode selector 29 opens the switch 21 and the current switch 17, and the switch 28
Let be closed. As a result, no signal is input to the drive mechanism 18, and operation is performed while the position of the scoop pipe 6A is fixed. Generally, a nuclear reactor is operated in this constant hold mode for most of its operating time. Further, when a runback command signal is output in response to a request from the plant, a sudden decrease signal is output from the sudden decrease signal generator 23 or 25.
At this time, the switch 21 and the current switch 17 are closed, and the drive mechanism 18 performs a runback in response to this sudden decrease signal. The operation will be explained based on the above configuration.
First, a case where operation is performed in the conventional feedback control mode will be explained. In this case, the control mode selector 29 first selects the feedback control mode. As a result, switch 2
0, 21, 22 and current switch 17 are closed, and switches 24, 26 and 28 are opened. As a result, control is performed in which the speed setting signal and the MG speed detection signal are compared and a position request signal is output so that both signals match. This feedback control mode need only be selected when it is necessary to manipulate the reactor output by adjusting the core cooling water flow rate. Next, the case of operation in the constant holding mode will be explained. That is, since the core cooling water flow rate is constant during most of the reactor operating time, in such a case, the control mode selector 29 selects the constant hold mode and operates in the constant hold mode. In this case, switch 21 and current switch 1
7 is open, and switch 28 is closed. Also, switches 20 and 22 are closed, and switches 24 and 26 are open. Therefore, in this case, the operating rod 6B is in a fixed state, and even if, for example, a failure or abnormality occurs in a component of the control system, the operating rod 6B will not be affected at all, and the operating rod 6B will not move. It is possible to prevent a situation in which the position of the scoop tube 6A changes, the cooling water flow rate fluctuates, and the output fluctuates unnecessarily, or the nuclear reactor unnecessarily comes to an emergency shutdown due to high neutron flux. Further, at this time, the output signal of the speed controller 13 equipped with proportional and integral calculation elements is maintained in a state balanced with the position of the operating rod 6B when it is fixed. Therefore, as long as the setting by the speed setter 11 is not changed, no disturbance will occur in the speed controller 13 even if the control mode selector 29 returns to the feedback control mode. Furthermore, even if there is a change in the setting by the speed setting device 11, the speed setting device 11 must be adjusted so that the deviation becomes 0 on the unillustrated deviation meter of the first deviation calculator 10, and then the feedback control mode can be changed. If it is returned to , no disturbance will occur. If the output signal of the speed controller 13 and the position of the operating rod 6 are out of balance, an alarm generator 30 provided between the switch 28 and the position deviation signal converter 27 issues an alarm. Next, the case of operation in the plant command response mode will be explained. That is, the MG speed sudden decrease signal is generated from the sudden decrease signal generator 23 or 25. This causes the switch 20 to open and the switch 24 to close. Alternatively, the switch 22 is opened and the switch 26 is closed. Now the scoop pipe operation section 8
When the MG speed sudden decrease signal is inputted, the operating rod 6B responds via the drive mechanism 18 and a runback is performed. Also, if the MG speed sudden decrease signal occurs while operating in constant hold mode,
The switch 21 changes from open to closed, the switch 28 changes from closed to open, and the current switch 17 changes from open to closed.
As a result, an MG speed sudden decrease signal is input to the scoop pipe operating section 8, and a runback is performed. When operating in the constant hold mode, if an abnormality occurs in the position detector 19 or the speed controller 13 and the runback standby state is incomplete, the alarm generator 30 naturally issues an alarm. This will make the worker aware of the abnormality. As described above, according to the reactor recirculation system control device according to the present embodiment, constant speed operation is performed in the constant holding mode for most of the operating time, so even if a component of the speed control section 7 fails, for example, the drive mechanism 18 Since no signal is output to the reactor, it is possible to prevent situations such as fluctuations in the MG speed or emergency shutdown of the reactor due to high neutron flux, greatly improving the operating rate of the plant. . [Effects of the Invention] The nuclear reactor recirculation system control device according to the present invention includes a variable frequency generator that supplies variable frequency power to a recirculation pump drive motor, and a variable frequency generator that is connected to the variable frequency generator to vary the rotation of the drive motor. a fluid coupling that transmits transmission to the frequency generator; a scoop pipe that is provided on the fluid coupling and adjusts transmission of rotation by the fluid coupling;
a variable frequency generator speed detector that detects the speed of the variable frequency generator; a scoop tube operating section that operates the scoop tube; a speed control section that outputs a position request signal to the scoop tube operating section; A speed setting device provided in the control section for setting the speed, a speed setting signal from the speed setting device provided in the speed control section and a speed detection signal from the variable frequency generator speed detector are inputted and compared and calculated. a first deviation calculator that outputs a deviation signal; and a speed controller that is provided in the speed control section and receives the deviation signal from the first deviation calculator and outputs a request signal for the operating rod position of the scoop pipe. , a position detector provided in the scoop tube operating section to detect the position of the operating rod of the scoop tube, and inputting a position signal from the position detector provided in the scoop tube operating section and a position request signal from the speed controller. a second deviation calculator that performs comparison calculations and outputs a deviation signal, and a drive mechanism that is provided in the scoop pipe operating section and drives the operating rod of the scoop pipe based on the deviation signal from the second deviation calculator. and a first switch inserted between the first deviation calculator and the speed controller, and a position parallel to the speed controller and the second deviation calculator via the second switch. A deviation signal converter, a current switch inserted between the second deviation calculator and the drive mechanism, and a current switch provided in the speed control section to open and close the first switch, second switch, and current switch. a control mode selector that selects an operation mode by controlling the speed controller; and a control mode selector that is provided in the speed control section and sends a sudden reduction signal that causes the operating rod to respond to the runback via the drive mechanism when a runback command signal is issued. This configuration includes a deviation calculator or a sudden decrease signal generation mechanism that outputs to the second deviation calculator. In other words, when operating in the conventional feedback control mode, the control mode selector closes the first switch and the current switch, and closes the second switch.
Open the switch. This allows the speed setter,
Operation in the feedback control mode is performed on a route connecting the first deviation calculator, the speed controller, the second deviation calculator, and the drive mechanism. In addition, when operating in a constant holding mode, that is, with the scoop pipe position constant, the control mode selector selects the first
switch and the current switch are opened and the second switch is closed. This causes the scoop tube position to remain fixed and the output signal from the speed controller to remain balanced with the fixed operating rod position. Furthermore, when a runback operation is performed in response to a command from the plant, a sudden decrease signal is generated from the sudden decrease signal generating mechanism, which closes the first switch and the current switch, and the drive mechanism responds to the sudden decrease signal to perform the runback. This is the configuration that is performed. Therefore, most of the reactor operation time is spent selecting the constant hold mode using the control mode selector. During operation, no signals are input to the drive mechanism, so the rake tube fluctuates, the core cooling water flow rate changes, and the output fluctuates, or the output changes due to high neutron flux. There is no need for unnecessary emergency shutdown of the nuclear reactor, highly reliable control can be performed, and the operating rate of the plant can be greatly improved.

[Brief explanation of drawings]

1 and 2 are diagrams showing one embodiment of the present invention, in which FIG. 1 is a schematic system diagram of a nuclear reactor recirculation system control device, and FIG. 2 is a partially detailed diagram of FIG. 1. DESCRIPTION OF SYMBOLS 1... Variable frequency generator, 2... Recirculation pump, 3... Pump motor, 4... Fluid coupling, 5...
... Drive motor, 6A ... scoop pipe, 6B ... operation rod, 7 ... speed control section, 8 ... scoop pipe operation section,
9... Variable frequency generator speed detector, 10... First deviation calculator, 11... Speed setter, 13...
Speed controller, 14... Second deviation calculator, 17...
...Current switch, 18... Drive mechanism, 19... Position detector, 21... Switch (first switch), 23,
25...Sudden decrease signal generator, 28...Switch (second
switch), 20, 22, 24, 26... switch,
27...Position deviation signal converter, 29...Control mode selector.

Claims (1)

[Scope of Claims] 1. A variable frequency generator that supplies variable frequency power to a recirculation pump drive motor, a fluid coupling connected to the variable frequency generator and transmitting rotation of the drive motor to the variable frequency generator; a scoop pipe provided in the fluid coupling to adjust transmission of rotation by the fluid coupling, a variable frequency generator speed detector to detect the speed of the variable frequency generator, and a scoop pipe operating section to operate the scoop pipe; a speed control section that outputs a position request signal to the scoop pipe operating section; a speed setter provided in the speed control section that sets the rotational speed of the variable frequency generator; and a speed setting device provided in the speed control section that sets the speed. a first deviation calculator that inputs a speed setting signal from the variable frequency generator speed detector and a speed detection signal from the variable frequency generator speed detector, performs a comparison operation, and outputs a deviation signal; a speed controller that inputs a deviation signal from a deviation calculator and outputs a request signal for the operating rod position of the scoop pipe; and a position detector that is provided in the scoop pipe operating section and detects the position of the operating rod of the scoop pipe. and,
a second deviation calculator provided in the scoop pipe operating section and inputting a position signal from the position detector and a position request signal from the speed controller, performing comparison calculations and outputting a deviation signal; a drive mechanism that is provided in the operating section and drives an operating rod of the scoop pipe based on the deviation signal from the second deviation calculator;
a first switch inserted between the first deviation calculator and the speed controller; and a positional deviation installed in parallel with the speed controller and the second deviation calculator via a second switch. a signal converter, a current switch interposed between the second deviation calculator and the drive mechanism, the first switch and the second switch provided in the speed control section;
a control mode selector that selects an operation mode by controlling the opening and closing of the switch and the current switch; and a control mode selector that is provided in the speed control section and causes the operating rod to respond via the drive mechanism when a runback command signal is issued. The sudden decrease signal that causes the runback to be sent to the first
A nuclear reactor recirculation system control device comprising: a deviation calculator or a sudden decrease signal generation mechanism that outputs to the second deviation calculator. 2. The nuclear reactor recirculation system control device according to claim 1, wherein the position deviation signal converter is equipped with an alarm generator and issues an alarm when the deviation becomes large.