JPH0344599A - Controlling apparatus of recirculation flow rate of reactor coolant - Google Patents

Abstract

PURPOSE:To facilitate a safe and efficient automatic operation control of an atomic power plant by calculating an effective speed change rate automatically in consideration of the situation of each part of the power plant, beginning with a reactor, after a momentary stop thereof. CONSTITUTION:A speed request signal S22 is inputted to a frequency restrictor 8 via an upper-lower limit limiter 6 and a change rate restrictor 7 and an appropriate frequency matched with a requested speed is set therein. When a momentary stop occurs in a power source system herein, a normally-open contact 23 is closed and a switching contact 25 is switched. With the normally-open contact 23 closed, a real speed signal S19, which is a speed of rotation of PLR pump motor 13 at the time point of occurrence of the momentary stop, is read in a memory 21, while the real speed signal S19 of the PLR pump motor 13 generated on the occurrence of the momentary stop or after is inputted to a speed change rate setting unit 22 through the normally-open contact of the switching contact 25. It is outputted as the request signal S22 to a stationary- type variable-frequency power source device 5 and thereby the speed of the PLR pump motor 13 is reduced.

Description

[Detailed Description of the Invention] [Object of the Invention] (Field of Industrial Application) The present invention employs a static variable voltage frequency power supply device as a drive power source for a reactor coolant recirculation pump motor in a nuclear power plant. , relates to a nuclear reactor coolant recirculation flow control device that provides speed setting.

(Prior art) In a nuclear power plant, one of its output adjustment elements is
One of the functions is to control the recirculation flow rate of coolant in the reactor core. The power source for driving the reactor coolant recirculation pump motor (hereinafter referred to as PLR pump motor) for this purpose includes:
In recent years, static variable voltage frequency power supplies (inverters) have been increasingly adopted due to their good responsiveness and maintainability.

In such a power supply device, when an instantaneous power outage (hereinafter referred to as an instantaneous power outage) occurs due to an abnormality in the power supply system of the nuclear power plant, the static variable voltage frequency power supply device has a quick response speed because it is a semiconductor device. Therefore, the output voltage and frequency are likely to drop temporarily, causing fluctuations in the output of the nuclear power plant.

FIG. 2 shows a block diagram of a conventional reactor coolant recirculation flow control system, in which an operator sets the speed of the recirculation pump through an operator console 2 in the recirculation flow control system 1. Inputting this speed setting signal S2 and the plant information signal S3 necessary for speed control, the speed controller 4 calculates an appropriate speed request value and outputs a speed request signal S4 to the stationary variable frequency power supply device 5. This speed request signal S4 is inputted to a frequency limiter 8 via an upper and lower limiter 6 and a rate of change limiter 7 for stable operation, and an appropriate frequency matching the required speed is set. This output frequency setting signal S8 is converted into a pulse signal S9 by a pulse amplifier 9 and inputted to an inverter circuit IO. This inverter circuit
At O, an output current 11 (alternating current) with a frequency requested by the pulse signal S9 is output, and this output current 11 is boosted by an output transformer 121 and is sent to the PLR pump motor 13.
to operate the reactor.

If an instantaneous power outage occurs in the power supply system for some reason, the normally closed contact b15 opens and the normally open contact al13 closes due to the instantaneous power outage signal SL4. Although the speed request signal S4 from the recirculation flow rate control device 1 is stopped by the normally closed contact b15,
At the same time, the voltage of the output current ti is reduced by the instrument transformer 17 from the normally open contact a16, and the actual speed signal S19 converted by the voltage/frequency converter 18 is converted into the speed request signal S4 and input to the upper and lower limiter 6. A closed loop circuit is formed, and the PLR pump motor 13 is decelerated.

When the momentary power failure is restored in this state, the momentary power failure signal S14 is released, so the normally closed contact b15 closes and the normally open contact ate opens. As a result, the speed request signal S4 from the recirculation flow rate control device 1 is again input to the upper and lower limiter 6, but at this time, due to the speed reduction of the PLR pump motor 13 during the instantaneous power failure, the speed request signal S4>actual speed signal Since it is in the state of S19,
The speed of the PLR pump motor 13 is automatically increased at a constant rate of change set by the rate of change limiter 7 in the static variable frequency power supply 5 to the speed set before the instantaneous power failure.

(Problem to be Solved by the Invention) When a momentary power failure is recovered using a conventional recirculation flow rate control device, the speed of the PLR pump motor that has previously decreased is automatically increased to the set speed; The rate of change is limited at a constant rate according to the characteristics of a rate of change limiter included in the static variable frequency power supply. However, the effects of a momentary power outage in a nuclear power plant include not only a decrease in the speed of the PLR pump motor but also a decrease in the speed of the main pumps in each process, and various transient changes are expected. Particularly in a nuclear reactor, power increase operation due to a rapid increase in the recirculation flow rate of coolant is undesirable because of the effect it has on the reactor core. For this reason, in the past, this was done by sufficiently reducing the rising rate of change characteristic of the rate of change limiter in the static variable frequency power supply, or by manual operation by an operator. However, if the rate of increase is small, the normal recovery of the nuclear power plant will be delayed and the power system will be adversely affected.Manual operation requires a lot of experience from the operator, and the timing of momentary power outages is uncertain. There was a problem that the burden on the operator increased.

The present invention has been made in view of the above, and its purpose is to instantly provide a recirculation flow rate control device that issues a PLR pump motor speed control signal to a static variable frequency power supply device that is a drive power source for the PLR pump motor. PLR at the time of outage
A reactor cooling system that automatically and safely increases the PLR pump motor speed to the set speed when recovering from a momentary power failure by providing a memory means for the pump motor speed and a speed change rate setting means suitable for the characteristics of the nuclear power plant. An object of the present invention is to provide a material recirculation flow rate control device.

[Structure of the Invention] (Means for Solving the Problems) A static variable voltage frequency power supply device that is a driving power source for a coolant recirculation pump motor of a nuclear reactor, and a speed control requirement for this static variable voltage frequency power supply device. A recirculation flow rate control device that outputs a signal inputs a speed setting signal, a plant information signal, and an actual speed signal of the recirculation pump motor at the time of momentary power outage, and a speed control means that outputs a speed request signal; memory means for reading an actual speed signal of the recirculation pump motor of the recirculation pump motor and outputting it to the speed control means when an instantaneous power failure is restored; During a power outage, the actual speed signal of the recirculation pump motor is inputted, and when the instantaneous power outage is restored, the speed request signal from the speed control means and the actual speed signal of the recirculation pump motor at the time of occurrence of the instantaneous power outage from the memory means are input. Then, when the power supply system is normal, the speed setting signal, the actual speed signal of the recirculation pump motor during a momentary power outage, and the actual speed of the recirculation pump motor at the time of recovery from the momentary power outage. A speed change rate setting means is provided for calculating and outputting a speed change rate suitable for the nuclear power plant from the deviation between the signal and the actual speed signal of the recirculation pump motor at the time of momentary power outage and the plant information signal.

(Function) The stationary variable voltage frequency power supply device, which is the drive power source for the recirculation pump motor, receives a signal based on the speed setting signal set on the operator console when the power system is normal, and a voltage/frequency signal during a momentary power outage. The signal is based on the actual speed signal of the recirculation pump motor from the frequency converter, and when the momentary power outage is restored, the actual speed signal of the recirculation pump motor at the time of recovery from the momentary power outage and the actual speed signal of the recirculation pump motor at the time of the momentary power outage from the memory. Input each speed signal together with the plant information signal to the speed change rate setting means to calculate and output the optimum speed change rate for the nuclear power plant concerned, and automatically and quickly increase the speed of the recirculation pump motor to a predetermined value. let

(Example) An embodiment of the present invention will be described with reference to the drawings.

Note that the same components as those in the prior art described above are given the same reference numerals and detailed explanations will be omitted.

FIG. 1 is a block configuration diagram, in which the recirculation flow rate control device 20 includes an operator console 2 through which the operator sets the speed of the recirculation pump, a speed setting signal S2 from now on, and a power generation plant information signal S3 necessary for speed control. A speed controller 4 which is a speed control means that inputs an input, calculates an appropriate speed request value, and outputs a speed request signal S4, and a PL at the time of momentary power failure.
A memory 21 is a memory means for reading the actual speed signal S19 of the R pump motor 13, and the power generation plant information signal S
3. A speed change rate setting means that inputs the speed request signal S4 or the actual speed signal S19 and outputs a request signal 522 based on a speed change rate suitable for the characteristics of the nuclear power plant to the stationary variable frequency power supply device 5. Rate of change setter 22
It further comprises a normally open contact a23 that closes in response to the instantaneous power failure signal S14, a normally closed contact b24 that opens, and a switching contact c25 that opens and closes. Note that the actual speed signal S19 from the voltage/frequency converter 1B is input to the memory 21 via a normally open contact a23, and is connected to the speed change rate setter 22 via a normally open contact of a switching contact c25. Furthermore, the memory 21 and the speed controller 4 are connected via a normally closed contact b24, and the actual speed signal S2 at the time of momentary power failure is output from the memory 21.
1 is input to the speed controller 4. Further, the speed controller 4 and the speed change rate setter 22 are connected via a normally closed contact of a switching contact c25. Note that the static variable frequency power supply device 5 that inputs the request signal S22 from the recirculation flow rate control device 20 has an upper and lower limiter 6 for stable operation, and a rate of change similar to the conventional static variable frequency power supply device 5 described above. A limiter 7, a frequency limiter 8 that sets an appropriate frequency that matches the required speed, a pulse amplifier 9 that converts the output frequency setting signal S8 into a pulse signal S9, and this pulse signal S9.
an inverter circuit IO that outputs an output current 11 (alternating current) with a frequency requested by , an instrument transformer 17 that reduces the pressure of this output current 11, and a voltage/frequency converter that outputs an actual speed signal S19 of the PLR pump motor 13. It is composed of a container 18. In addition, the static variable frequency power supply device 5 is connected to a PL via an output transformer 12 that boosts the output current 11.
An R pump motor 13 is connected.

Next up fc! The effects of the configuration will be explained. Normally, an operator sets the speed of the recirculation pump using the operator console 2 in the recirculation flow rate control device 20, inputs this speed setting signal S2 and the power generation plant information signal S3 necessary for speed control, and controls the speed controller. 4 calculates an appropriate speed request value and switches the speed request signal S4 to a stationary type request signal S22 with a speed change rate optimal for the nuclear power plant via the normally closed contact of the contact c25 and the speed change rate setter 22. Output to variable frequency power supply device 5. This request signal S22 is inputted to the frequency limiter 8 via the upper and lower limiter 6 and the rate of change limiter 7, and an appropriate frequency matching the required speed is set. This frequency setting signal S8 is converted into a pulse signal S9 by a pulse amplifier 9 and input to an inverter circuit 10. In this inverter circuit 10, the pulse signal S
9 outputs an output current 11 (alternating current) of the requested frequency, and this output current 11 is stepped up by the output transformer 12 to drive the PLR pump motor 13 at the requested speed.

The actual speed of this PLR pump motor 13 is determined by an actual speed signal 519 from the instrument transformer 17 and the voltage/frequency converter 18.
This is output to the normally open contacts a23 and the switching contact C25. As a result, the reactor is automatically controlled and operated at a predetermined output.

If a momentary power failure occurs in the power supply system for some reason, the power supplied to the inverter circuit 10 disappears, and the output current 11 to the PLR pump motor 13 is interrupted. At this time, the instantaneous power failure signal 514 causes the normally open contact a23 to close, the normally closed contact b24 to open, and the switching contact c25 to switch to the normally open contact side. By closing the normally open contact a23, the actual speed signal S19, which is the speed of the PLR pump motor 13 at the time of momentary power failure, is read into the memory 21, and the switching contact c
An actual speed signal S19, which is the speed of the PLR pump motor 13 after the instantaneous power failure has occurred, is input to the speed change rate setting device 22 through the normally open contact point 25 instead of the speed request signal S4 from the speed controller 4. It is output as a request signal S22 to the stationary variable frequency power supply device 5 to form a closed loop circuit and output to the PL.
The R pump motor 13 is decelerated.

Next, when the instantaneous power outage is restored in this state, the instantaneous power outage signal S1
4 is released, the normally open contact a23 opens and the normally closed contact b24 closes. Furthermore, the switching contact c25 is switched to the normally closed contact side. As a result, the actual speed signal S21 at the time of the instantaneous power failure from the memory 21 is input to the speed change rate setter 22 as the speed request signal S4 via the speed controller 4, and the actual speed during the instantaneous power failure that had been input until then is input to the speed change rate setting device 22. From the comparison calculation with the actual speed signal SL9 at the moment of recovery from the instantaneous power outage and the plant information signal S3 necessary for setting the speed change rate, for example, maintaining a predetermined output increase rate for the reactor core, The speed change rate setter 22 selects an optimum speed change rate that quickly reaches the actual speed and the speed according to the speed setting signal S2, and sends a request signal S22 according to this to the speed change rate setter 22. To automatically and safely increase the speed of a PLR pump motor 13 to a predetermined speed without adversely affecting each part of the plant.

[Effects of the Invention] According to the present invention, the reactor coolant recirculation flow rate control device does not require operation by an operator, and the stationary variable frequency power supply device is controlled at the time of instantaneous power failure and at the time of restoration of the power supply system. By understanding the output voltage and frequency decrease and the resulting decrease in the speed of the reactor coolant recirculation pump, we can calculate the effective speed change rate that takes into account the situation after a momentary power outage in the reactor and other parts of the power plant. The automatic calculation allows for early return to normalization of the reactor coolant recirculation pump speed in a safe and efficient manner, making safe and efficient automatic operation control of nuclear power plants easier and reducing the burden on operators. It also has the effect of reducing

[Brief explanation of drawings]

FIG. 1 is a block diagram of an embodiment of the present invention, and FIG. 2 is a block diagram of a conventional reactor coolant recirculation flow rate control device. 2... Operator console, 4... Speed setting device, 5... Static variable frequency power supply device, 6... Upper and lower limit limiter, 7... Rate of change limiter, 8... Frequency controller , 9...1<)
response amplifier, 10... inverter circuit, 12.
... Output transformer, 13... PLR pump motor, 18... Voltage/frequency converter, 20... Recirculation flow rate controller, 22... Speed change rate setting device, 24... Normally closed Contact, 21...Memory, 23...Normally open contact, 25...Switching contact.

Claims (1)

[Claims] A static variable voltage frequency power supply device is used as a driving power source for a recirculation pump motor that circulates coolant in the reactor core, and
A recirculation flow control device that issues a speed control request signal to the stationary variable voltage frequency power supply receives a speed setting signal, a plant information signal, and an actual speed signal of the recirculation pump motor at the time of a momentary power failure in the power system. speed control means for outputting a speed request signal; memory means for reading an actual speed signal of the recirculation pump motor at the time of instantaneous power outage and outputting it to the speed control means at the time of recovery from the instantaneous power outage; and the plant information signal and power supply system. During normal operation, the speed request signal from the speed control means, and during a momentary power outage, the actual speed signal of the recirculation pump motor, and when the momentary power failure is restored, the speed request signal from the speed control means and the instantaneous signal from the memory means. Input the actual speed signal of the recirculation pump motor at the time of a power outage, obtain its deviation, and use the speed setting signal when the power supply system is normal, and the actual speed signal of the recirculation pump motor during a momentary power outage. When a power outage is restored, the deviation between the actual speed signal of the recirculation pump motor at the time of restoration of the instantaneous power outage and the actual speed signal of the recirculation pump motor at the time of the instantaneous power outage,
A nuclear reactor coolant recirculation flow rate control device comprising a speed change rate setting means that calculates and outputs a speed change rate suitable for the nuclear power plant from a plant information signal.