JPS61134700A - Load follow-up controller for nuclear reactor - 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 [Technical Field of the Invention] The present invention relates to a nuclear reactor load follow-up control device that performs automatic follow-up control in response to load demands of a boiling water nuclear power plant.

[Technical background of the invention]

The reactor load follow-up control device controls the generator load, steam turbine speed, main steam pressure, and opening degrees of the main steam control valve and turbine bypass valve to control the reactor output to II'H. According to the conventional device, the main steam control valve is operated by the minimum signal of the three signals: the load request signal, the load control signal, and the total steam flow rate signal, and the error signal between the load request signal and the total steam flow rate signal is used as the load following signal. The configuration is such that the output is output to the reactor power control device to control the reactor power. In this control device, during load following operation, the load control signal is set to a larger value than the other two signals, so the load request signal and the total steam flow rate request signal are used to control the opening of the regulating valve and the reactor output control. It can be done automatically.

FIG. 4 shows a schematic configuration of a conventional reactor load follow-up control device, in which the main steam sent out from the reactor pressure vessel 1 is
A steam turbine 3 is driven via a main steam control valve 2, and this steam turbine 3 drives a generator 4. On the other hand, the main steam after driving the steam turbine 3 is condensed and liquefied in the condenser 5,
The water is returned to the reactor pressure vessel 1 by the feed water pump 6. Further, reference numeral 7 indicates the main steam sent out from the reactor pressure vessel 1.
This is a turbine bypass valve that bypasses the main steam control valve 2 and the steam turbine 3 and sends the steam to the condenser 5.

Further, the coolant inside the reactor pressure vessel 1 is forcedly circulated by a recirculation system 8.

The reactor power control device 11 multiplies a speed deviation signal, which is the deviation between the speed setting signal a and the turbine speed signal S, by the reciprocal of the speed setting rate, and outputs a corrected speed deviation signal C. Here, the speed setting rate is the control valve flow rate (hereinafter referred to as CV flow rate) of 100
The speed deviation required to change the speed from 0% to 0% is expressed as a percentage of the rated speed.

The reactor pressure control device 12 inputs a pressure deviation signal that is the deviation between the main steam control valve @d and the pressure setting signal e, performs lead/lag compensation on this pressure deviation signal, and then multiplies it by the reciprocal of the pressure setting rate. A total steam flow rate request signal f is output. Here, the pressure setting rate is the pressure deviation required to increase the CV flow rate from 0% to 100%, expressed as a percentage of the rated pressure.

The low value priority circuit 13 outputs the reactor output request signal obtained by adding the load setting signal Q to the corrected speed deviation signal C, the adjustment valve opening request signal, the load limit signal i, and the maximum total steam flow rate limit signal j. is input to the cvta limit signal, the signal with the minimum value is selected from each input signal, and the CV flow rate setting signal λ is output to the servo valve 14. Therefore, the servo valve 14 adjusts the opening degree of the steam control valve 2 based on this CV flow rate setting signal 2 to control the CV flow rate.

The low value priority circuit 15 compares the deviation signal between the regulating valve opening request signal f and the C■ flow rate setting signal 2, and the deviation signal between the maximum total steam flow rate restriction signal J and the Cv flow rate setting signal 2, and selects the smaller one. The deviation signal is selected and a bypass valve flow rate (hereinafter referred to as BPV flow rate) setting signal m is output to the servo valve 16. Therefore, the servo valve 16 adjusts the opening degree of the turbine bypass valve 7 based on this 8PV flow rate setting, and controls the BPV flow rate.

The deviation signal obtained by comparing the signal obtained by subtracting the flow rate bias signal n from the reactor output request signal and the adjustment valve opening request signal f is used as the load following signal p to switch 1.
7 to the reactor recirculation flow control device 18 .

Therefore, the reactor recirculation flow rate control device 18 controls the recirculation system 8 based on this load follow-up signal p, and controls the reactor output.

Here, the flow rate bias signal n acts to make the regulating valve opening request signal f smaller by the bias amount than the reactor output request signal in the steady operating state, and in the steady operating state, the reactor pressure control device 12 It has the function of controlling the flow rate.

The switch 17 opens when the reactor recirculation flow rate control device 18 is manually operated, and disconnects the load following signal p from the reactor recirculation flow rate control device 18 . In addition, when performing load following operation, the switch 17 is closed and the load limit signal i
, maximum total steam flow rate restriction signal j and C ■ flow rate restriction signal k
is set to a larger value by the reactor output request signal and the adjustment valve opening request signal, and normally the Cv flow l is controlled by the reactor output request signal and the adjustment valve opening request signal f, and the reactor output is I'm trying to control it.

Next, the operation of the reactor load follow-up control device configured as above will be explained.

For example, when the power system load increases, the balance between the total power system load and the power plant output is lost, and the system frequency decreases, which is manifested as a decrease in the turbine speed signal S, and the corrected speed deviation signal C is on the positive side. increases to As a result, the reactor power request signal and the load follow signal p increase, and since the switch 17 is closed, the reactor recirculation flow control device 18 operates to increase the reactor power. In this way, the control valve opening request signal f increases, the opening of the main steam control valve 2 is increased, and the turbine output is increased. At this time, the reactor output request signal is directly controlled by the low value priority circuit 13!
l The setting signal 2 is not set, but the reactor recirculation flow rate control device 18 is operated once to increase the reactor output, that is, the main steam pressure signal d is increased, and the adjustment valve opening is changed via the reactor pressure control device 12. The request signal f is increased, and this signal f passes through the low value priority circuit 13 and becomes the CvRI setting signal@°C, increasing the opening degree of the main steam control valve 2 and increasing the output of the steam turbine 3.

[Problems with background technology]

In the above configuration, response delay included in the reactor recirculation flow rate control device 18 in response to a load increase request from the power system;
Responsiveness cannot necessarily be said to be fast because of the reactor output response delay and the response delay included in the reactor pressure control system M12.

On the other hand, in Japan, nuclear couplers currently operate at a constant maximum possible output due to the low cost of power generation. However, if nuclear power plants are installed in the future and the proportion of nuclear power in the power grid increases, measures will be taken to deal with late-night surplus loads, adjust supply and demand during the day, maintain grid frequency, etc.
It is clear that there will be a need for operations similar to those of current thermal power plants, and in preparation for this prospect, there is a demand for improvements in the load followability of nuclear couplants.

[Purpose of the invention]

The present invention has been made with these circumstances in mind, and an object of the present invention is to provide a nuclear reactor load follow-up control system that can quickly and smoothly perform load follow-up in response to load demands of a nuclear couplant.

[Summary of the invention]

In order to achieve the above object, the reactor load follow-up control device of the present invention inputs the reactor output request value to a computing unit, divides it into frequencies, adds the high frequency component to the opening degree request value, and adds the high frequency component to the It is characterized in that a deviation signal between the frequency component and the required value for the adjustment valve opening is input to the recirculation flow rate control device.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIGS. 1 and 2. Note that the same parts in FIGS. 1 and 2 as in FIG. 4 are designated by the same reference numerals.

Fig. 1 shows a schematic configuration of a reactor load follow-up control system, and the difference from the system shown in Fig. 4 is that the components of the corrected speed deviation signal C are input to a calculator 21 and frequency-divided there. ,
For high frequency components of 0.5 Hz or more, the opening degree of the regulating valve 2 is directly controlled, and only low frequency components S of less than 0.5 Hz are added to the load setting signal Q and input to the low value priority circuit 13. This is the point.

As shown in FIG. 2, this computing unit 21 includes a first-order lag filter 22 that cuts high frequency components, and a load request that limits the load request when a load request is made that is larger than a limit value for plant protection and operation. This configuration is equipped with a limiter 23 that allows

FIG. 3 shows input and output signals of the arithmetic unit 21.

That is, the corrected speed deviation signal C (upper part of FIG. 3) that detects the load request of the power system includes various frequency components. This corrected speed deviation signal C is input to the arithmetic unit 21, and the high frequency component element (lower part of Figure 3) and the low frequency component S (middle part of Figure 3)
The frequency is divided into Then, the corrected speed deviation signal high frequency component element is added to the output signal of the low frequency priority circuit 13,
C■ Inputted to the servo valve 14 as the flow rate setting signal 2.

In addition, the corrected speed deviation signal low frequency component S is the load setting signal Q
The deviation signal obtained by comparing the signal obtained by subtracting the Nagareyama bias signal n from the reactor output request signal obtained by addition and the adjustment valve opening request signal f is the load following signal p. is input to the reactor recirculation flow rate control device 18 via the switch 17.

Therefore, for high-frequency components with small changes in the load demand, a quick response can be achieved by directly controlling the CV flow rate, and for low-frequency components with large changes, by controlling the reactor output. This enables smooth response similar to that of conventional devices.

Note that the present invention is not limited to the above embodiments. For example, instead of the first-order lag filter 22 in FIG.
It is also possible to use a notch filter that cuts specific frequency components. By using a notch filter, only the necessary frequency components can be extracted via the calculator 21, unnecessary minute fluctuations can be cut, and the characteristics of multiple boiling water nuclear power plants (BWR power plants) can be extracted. By using notch filters with different frequency components, it is also possible to perform load following operation by sharing the frequency components.

〔Effect of the invention〕

As described in detail above, the present invention has a reactor pressure control device and a reactor power control device, and the output of either of these control devices is used to control the communication between the reactor pressure vessel and the steam turbine. In addition to controlling the opening degree of the main steam control valve interposed between the two, the deviation signal between the reactor output request value and the control valve opening request value is input to the reactor recirculation flow rate control device to perform load follow-up control. Reactor load tracking! In the 11it device, the reactor output request value is input to a calculator, frequency-divided, the high frequency component is added to the adjustment valve opening request value, and a deviation signal between the low frequency component and the adjustment valve opening request value is obtained. It is characterized by being input to a recirculation flow rate control device. Therefore, by directly controlling the opening degree of the main steam control valve for the high frequency component of the reactor output requirement value frequency-divided by the computing unit, rapid load follow-up can be performed in accordance with the load requirement of the nuclear couplant. In addition, the low frequency component of the reactor output request value is added to the adjustment valve opening request signal, and the deviation signal is input to the reactor recirculation flow control device as a load follow-up signal. Regarding large low frequency components, smooth response similar to the conventional device is possible.

[Brief explanation of drawings]

Figures 1 to 3 show an embodiment of the present invention.
Figure 1 is a block diagram showing the schematic configuration of the reactor load tracking-m+ device, Figure 2 is a block diagram showing the schematic configuration of the arithmetic unit that is part of the device, and Figure 3 is the block diagram showing the schematic configuration of the arithmetic unit that is part of the device. FIG. 4 is a 70-step diagram showing a conventional reactor load follow-up control system. 1... Reactor pressure vessel, 2... Main steam control valve, 3...
... Steam turbine, 11 ... Nuclear reactor power control device, 1
2...Reactor pressure control device, 18...Reactor recirculation flow rate control device, 21...Arithmetic unit, 22...-order lag filter, 23...Restrictor, f...Adjustment Valve opening request signal, h...Reactor output request signal, r...High frequency component of the reactor output request signal, S...Low frequency component of the reactor output request signal.

Claims (2)

[Claims] (1) It has a reactor pressure control device and a reactor power control device, and depending on the output of either of these control devices, the main steam control valve interposed between the reactor pressure vessel and the steam turbine In the reactor load follow-up control device, which controls the opening degree of the reactor and performs load follow-up control by inputting a deviation signal between the reactor output request value and the adjustment valve opening request value to the reactor recirculation flow rate control device. The reactor output request value is input into a calculator and frequency-divided, the high frequency component is added to the control valve opening request value, and the deviation signal between the low frequency component and the control valve opening request value is recirculated to the flow rate control device. A nuclear reactor load follow-up control device characterized by inputting an input into the reactor load following control device. (2) The arithmetic unit is equipped with a first-order lag filter that cuts high-frequency components and a limiter that limits a load request that is larger than a limit value for plant protection and operation. A nuclear reactor load follow-up control device according to scope 1.