JPH0843589A - Test device and test method for main steam control valve - Google Patents

Abstract

PURPOSE:To provide a test device and test method for steam control valve capable of justifying non-linearity compensation characteristics of opening flowrate characteristics by providing a pressure control device with an opening direction test device and enabling testing full open of each main steam control valve in a low power operation state of a nuclear power plant. CONSTITUTION:The test device for a main steam control valve controls steam pressure by the main steam control valve inserted in the main steam piping. Between a function generator 15 for compensating the non-linearity characteristics of opening flowrate characteristics of the main steam control valve 3a to 3b and outputting opening demand signal and a control valve servo 16 for driving and controlling the main steam control valve, a test device consisting of a low value priority circuit 22 input by a closing direction test bias signal 25 from a closing direction signal generator 25 and a high value priority circuit 29 connected by an opening direction signal generator 28 outputting an opening direction test bias signal 27 and a deviation operator 23, is provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure control device for a boiling water nuclear power plant, and more particularly to a main steam control valve test device and a test method for confirming the opening degree and flow rate characteristic of the main steam control valve.

[0002]

2. Description of the Related Art In a boiling water nuclear power plant, main steam generated in a nuclear reactor is consumed in a turbine via a main steam pipe and a main steam control valve. At this time, the opening degree of the main steam control valve is set so that the pressure of the main steam is set to a value according to a preset adjustment rate in order to perform stable steam inflow to the turbine regardless of the output level of the reactor. The pressure controller controls the pressure value of the main steam and the preset pressure setting value.

As shown in the schematic configuration diagram of FIG. 2, this pressure control device has a main steam generated in the nuclear reactor 1 during a normal power generation operation by main steam pipes 2 and four main steam control valves 3a ...
Flow to turbine 4 via 3d.

The turbine 4 is rotated by the energy of the steam flowing into the turbine 4, and the generator 5 directly connected to the turbine 4 is driven to generate electric power. This turbine 4
The main steam consumed in 1 is returned to water in the condenser 6 and returned to the reactor 1 again via the water supply pipe 7.

The pressure control device comprises main steam control valves 3a to 3d.
The main steam and the pressures of the reactor 1 are controlled by setting an opening corresponding to the amount of steam generated in the reactor 1 to the main steam detected by the pressure detector 8 provided in the preceding stage of the main steam control valves 3a to 3d. Deviation calculator for steam pressure signal 9 and pressure set value 10
Enter in 11.

Further, a pressure regulator 13 for calculating a request signal 12 for the main steam flow rate based on the output of the deviation calculator 11,
A function generator 15 that converts the main steam flow rate request signal 12 from the pressure regulator 13 into an opening request signal 14 for the main steam control valves 3a to 3d, and an opening request signal 14 that is an output of the function generator 15.
The control valve servo 16 is used to control the opening of the main steam control valves 3a to 3d.

The pressure regulator 13 has a main steam flow rate request signal.
It consists of a proportional gain for calculating 12 and a lead / lag time constant function for optimizing the responsiveness of pressure control. The proportional gain of main steam pressure 9 and pressure set value 10 during operation at the rated output. The deviation is approximately 2 kg / cm ² and the main steam flow demand signal 12 is selected to be 100% rated.

The main steam flow rate request signal 12 which is the output of the pressure regulator 13 is input to the function generator 15 to calculate the opening degree request signal 14 of the main steam control valves 3a to 3d. The relationship between the opening flow rate characteristics of 15 and the main steam control valves 3a to 3d is shown in the characteristic curve diagrams of FIGS.

The characteristic curve diagram of FIG. 3 shows the main steam control valve 3a ...
3D shows the relationship between the opening degree and the flow rate. As shown by the curve 17, the main steam control valves 3a to 3d have a linear relationship between the flow rates at the respective opening degrees from the fully closed position to the middle position. Is. However, in the region from the middle opening to the fully closed region, the characteristic becomes non-linear, and the higher the opening, the smaller the change in the flow rate with respect to the opening change.

For this reason, as indicated by the solid line 18 in the characteristic curve diagram of FIG. 4, the function generator 15 for calculating the opening demand signal 14 of the main steam control valves 3a to 3d has a main steam flow demand signal. In the region where 12 is high, the main steam control valves 3a to 3d are changed so that the opening demands of the main steam control valves 3a to 3d are greatly changed.
Based on the design specifications of 3d, it is set so as to have the characteristic of the relationship of the curve 17 of FIG. 3 and the inside out.

As a result, in response to the main steam flow rate request signal 12 output from the pressure regulator 13, the main steam control valves 3a to 3d are supplied.
The flow rate of the steam flowing through is linear as shown by the solid line 19 in FIG. 5, and the control signal for pressure control and the linearity of the response are maintained over the entire power range of the reactor.

However, as shown by the dotted line 20 in FIG. 4, there is a difference between the design specifications of the main steam control valves 3a to 3d and the valve opening flow rate characteristics in the actual machine, and there is an error in the setting of the function generator 15. In this case, the linearity of pressure control is also shown by the dotted line 21 in FIG.
As shown in, the non-linearity becomes remarkable in the high output region.

As described above, in the pressure control device, normally, only the opening degree of the main steam control valves 3a to 3d is controlled to control the pressure. The main steam control valves 3a to 3d control the flow rate with respect to the opening degree. Since the characteristic is non-linear, the function generator 15 is provided with a function of compensating for the non-linear flow rate characteristic of the main steam control valves 3a to 3d in order to perform pressure control linearly and stably with respect to the reactor output. .

The non-linear characteristic compensation function set in the function generator 15 determines the set value based on the design specifications of the main steam control valves 3a to 3d at the beginning of construction of the nuclear power plant. During the operation of the plant, the pressure control function of the pressure control device always operates and the non-linear characteristic compensation function operates, so that the set value cannot be changed.

On the other hand, the non-linear actual characteristic of the flow rate with respect to the opening degree in the main steam control valves 3a to 3d is usually confirmed by
In the pressure control device, since the four main steam control valves 3a to 3d are controlled to have the same opening degree, it cannot be verified unless the reactor output is increased to the rated value.

Therefore, in the main steam control valves 3a to 3d, the main steam control valves 3a to 3d are operated up to the rated output due to the difference between the design specifications and the actual characteristics, and after confirming the valve opening flow rate characteristics, the reactor is temporarily stopped. Therefore, it is necessary to adjust the setting value for the nonlinear characteristic compensation in the function generator 15.

In the conventional pressure control device, each main steam control valve 3a is used as a test device in order to confirm whether the soundness of the opening / closing function of the main steam control valves 3a to 3d is maintained.
A closing direction test device as shown in the block diagram of FIG.

This is a closing direction signal generator in which a low value priority circuit 22 and a deviation calculator 23 are inserted on the output side of the function generator 15 and a closing direction test bias signal 24 is output to the low value priority circuit 22. 25 are provided and configured.

In this closing direction test apparatus, the opening direction request signal 14 from the function generator 15 and the closing direction test bias output from the closing direction signal generator 25 are output to the low value priority circuit 22 in a state under normal pressure control. Input signal 24.

As a result, the main steam control valves 3a ...
The opening degree of 3d is controlled to be lower than the opening degree during normal operation. At this time, the deviation calculator 23 receives the opening feedback signal 26 from the main steam control valves 3a to 3d, and when the output of the low value priority circuit 22 matches, the main steam control valves 3a to 3d are opened. The degree is maintained.

[0021]

[Problems to be Solved by the Invention] Main steam control valves 3a to 3
Regarding the confirmation test of the non-linearity compensation function with the opening flow rate characteristic of d, it is necessary to fully open the main steam control valves 3a to 3d. For this purpose, the output of the nuclear power plant must be increased to the rated output. did not become.

Moreover, when it is clear that the result of this confirmation test has a large difference from the design specification, the operation of the nuclear power plant is temporarily stopped and the function generator 15 can be readjusted. It was necessary, and there was a problem that the operating rate of the nuclear power plant was reduced.

An object of the present invention is to provide an opening direction test device in the pressure control device to enable a full-open test of each main steam control valve in a low power operation state of a nuclear power plant, and to provide an opening flow rate characteristic. It is to provide a test apparatus and a test method for a main steam control valve, which can verify the nonlinearity compensation characteristics of.

[0024]

In order to achieve the above object, a main steam control valve testing apparatus according to the invention of claim 1 comprises:
In the control device that controls the steam pressure by the main steam control valve etc. inserted in the main steam pipe from the reactor to the turbine,
Close the direction signal generator between the function generator that outputs the opening request signal by compensating the non-linearity of the opening flow rate characteristic of the main steam control valve and the control valve servo that drives and controls the main steam control valve. A test device comprising a low value priority circuit to which a direction test bias signal is input, a high value priority circuit to which an open direction signal generator that outputs an open direction test bias signal is connected, and a deviation calculator are provided. .

In the test method of the main steam control valve according to the second aspect of the present invention, the main steam control valve is normally operated for any one of a plurality of main steam control valves whose opening is controlled by the opening request signal of the same level. It is characterized in that the opening direction test bias signal is added to the opening request signal in the pressure control state, so that the opening degree of the main steam control valve is controlled to the fully opened position and held at an arbitrary opening degree.

According to a third aspect of the present invention, there is provided a method for testing a main steam control valve, in which a plurality of main steam control valves are sequentially driven to a fully open position in a low power operation state of a nuclear power plant, and the respective opening degrees are controlled. It is characterized in that the flow rate characteristic is evaluated and the setting of the function generator for compensating the non-linearity of the opening flow rate characteristic is performed.

According to a fourth aspect of the present invention, a main steam control valve test method is provided in which a main steam control valve test device is provided independently of a pressure control device, and the main steam control valve test device is connected each time the main steam control valve test is performed. It is characterized by doing.

[0028]

According to the first aspect of the present invention, in the test of the main steam control valve, the open direction test bias signal rising at a predetermined rate of change from the open direction signal generator of one main steam control valve to be tested. Is output to the high price priority circuit.

In the high value priority circuit, the opening direction request signal of the main steam control valve from the low value priority circuit is compared with the opening direction test bias signal, whichever is larger, and the opening direction test bias signal is determined to be the opening request signal. The signal to open the main steam control valve is output to the control valve servo via the deviation calculator when it exceeds the value to fully open the main steam control valve. This makes it possible to evaluate the non-linearity compensation of the flow rate characteristic with respect to the opening degree of the main steam control valve until it is fully opened. This test is sequentially performed for each main steam control valve.

According to a second aspect of the present invention, for any one of the plurality of main steam control valves, an opening request signal in a normal pressure control state in the high value priority circuit and an opening direction test from the opening direction signal generator. By adding a bias signal, the opening of the main steam control valve can be controlled to the fully open position, and the opening direction test bias signal can be held at an arbitrary opening to maintain the opening flow rate characteristic. Can evaluate the compensation function.

According to the third aspect of the present invention, in the low output operation state, the plurality of main steam control valves are sequentially driven to the fully open position, and the respective opening flow rate characteristics are evaluated.
It is possible to confirm the characteristics of each main steam control valve and adjust the setting of the function generator in the initial stage of starting the nuclear power plant.

According to the fourth aspect of the present invention, the test device for the main steam control valve is independent of the pressure control device, so that the pressure control device during normal operation can be the same as the conventional one.

[0033]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to the drawings. It should be noted that the same components as those of the above-described conventional technique are denoted by the same reference numerals and detailed description thereof will be omitted. As for the pressure control device, as shown in FIG. 2, the main steam pressure signal 9 detected by the pressure detector 8 and the deviation calculator 11 which inputs the pressure set value 10 and outputs the deviation signal, and the deviation calculator Main steam flow rate demand signal 12
It is equipped with a pressure regulator 13 for outputting.

The function generator 15 for inputting the main steam flow rate request signal 12 to compensate for the non-linearity characteristic of the opening flow rate characteristics of the main steam control valves 3a to 3d, and the opening request signal 14 of this output, A control valve servo 16 for driving and controlling the main steam control valves 3a to 3d is provided.

The present invention includes a function generator 15 for compensating the non-linear characteristic of the opening flow rate characteristics of the main steam control valves 3a to 3d of the pressure control device and outputting an opening request signal 14, and a main steam control valve. A test device for the main steam control valve is provided for each of the main steam control valves 3a to 3d between the control servos 16 for driving the control valves 3a to 3d.

As shown in the block diagram of FIG. 1, the main steam control valve testing apparatus has a low-direction test bias signal 24 input from the close-direction signal generator 25 to the output side of the function generator 15. High value priority circuit to which the value priority circuit 22 and the opening direction signal generator 28 that outputs the opening direction test bias signal 27 are connected
29 and the deviation calculator 23. In addition, the main steam control valve 3a driven and controlled by the control valve servo 16
The opening feedback signal 26 of 3d is used for the deviation calculator 23.
It is designed to be input to.

The low value priority circuit 22 and the closing direction signal generator
25 is a closing direction test device that compares the opening request signal 14 output from the function generator 15 with the closing direction test bias signal 24 and outputs the signal with the smaller value, and the high value priority circuit 29
The open direction signal generator 28 is an open direction test device that compares the opening request signal from the low value priority circuit 22 with the open direction test bias signal 27 and outputs the signal having the larger value.

Next, the operation of the above configuration will be described. Normally, the open direction test bias signal 27 output from the open direction signal generator 28 of the open direction test apparatus is the main steam control valve 3a.
Set up to 3d corresponding to fully closed. Thereby, the four main steam control valves 3a to 3d are connected to the pressure regulator 13 and the function generator.
The same is controlled by the opening request signal 14 from 15. Further, in this state, the operation of the closing direction testing device can be performed without any trouble.

In the test of the main steam control valves 3a to 3d, the opening direction test bias signal 27 of the opening direction signal generator 28 is increased at a predetermined rate of change for each main steam control valve to be tested. . This rate of change can be performed safely and stably for pressure control based on the response in normal pressure control and the actual results in the valve opening direction after the test in the conventional valve closing direction. I can decide.

As a result, when the opening direction test bias signal 27 of the opening direction signal generator 28 is the opening request signal 14 from the function generator 15 and exceeds the current opening degree of the main steam control valves 3a to 3d. Therefore, the opening degree of the main steam control valve to be tested begins to increase, and the control state of the pressure control device is deviated.

At this time, the main steam flow rate from the reactor 1 and the steam flow rate flowing into the turbine 4 did not change from the initial state, and the opening degree and flow rate of the main steam control valve during the test were carried out. Main steam control valve 3 to increase only
The main steam pressure in the preceding stages of a to 3d decreases, but this decrease in pressure is detected by the main steam pressure detector 8.

The pressure control device operates in response to this decrease in the main steam pressure, and the opening is reduced by the opening request signal 14 with respect to the other three main steam control valves except during the test. Main steam pressure is maintained normally.

The opening of the main steam control valve during the test can be maintained at an arbitrary opening by interrupting the increase of the opening direction test bias signal 27, and the increase of the opening of the valve from the initial state is , Corresponding to the amount of decrease in the valve opening degree of the other three groups.

These four main steam control valves 3a to 3d are designed and manufactured in the same size for all four units, and it is considered that steam flows evenly through the four units during normal operation. Main steam control valves 3a-3 in the process of increasing the output
Since the value of the main steam flow rate with respect to the opening degree of d can be easily measured and evaluated, the change amount of the main steam flow rate corresponding to the decrease in the opening degree of the other three valves other than the test valve is calculated. , It can be regarded as an increase in the steam flow rate of the test valve.

As described above, since the pressure control by the pressure control device is a proportional control system by the deviation signal between the main steam pressure and the pressure set value, one main steam control valve is under test. In the state where the pressure is controlled by the other three valves, the main steam pressure is slightly lower than that before the test, so if the pressure set value is adjusted during the test to match the main steam pressure to the initial state, More accurate evaluation is possible.

After completion of the test, the open direction test bias signal 27 is decreased in reverse to the start of the test, and when the opening degree reaches the same opening as that of the other three main steam control valves, the open direction signal is generated. By stopping the open direction test bias signal 27 from the vessel 28, the normal pressure control by the four main steam control valves 3a to 3d is restored.

The output of the reactor 1 which can be tested by the main steam control valve test device is that the flow rate of the main steam control valves 3a to 3d at the time of full opening is about 30% under normal pressure conditions. The minimum output that ensures stable pressure control by the main steam control valves 3a to 3d is about 10% immediately after the generator 5 is inserted, and the main steam control valves 3a to 3d at that time are
Approximately 40% because pressure control can be performed stably at an opening of 3d
The output is expected to be fairly low.

At the initial start-up of a nuclear power plant, the output is increased to the rated value after the operation and stop are normally repeated from a low output, and then the output is increased to the rated value. It is possible to evaluate the opening flow rate characteristic of 3d.

According to the present invention, it is possible to drive each of the plurality of main steam control valves 3a to 3d one by one during low power operation of the nuclear power plant to at least an arbitrary opening from the intermediate opening to the full opening. The opening flow rate characteristics of the main steam control valve to be tested can be evaluated from the widths in which the opening of the other three valves at that time are reduced by normal operation by the pressure control device.

The above-described test with the main steam control valve fully opened can be sequentially and easily performed on all the main steam control valves. In addition, when the nuclear power plant is operating at a low output and the total steam flow rate can be covered by three main steam control valves other than the test main steam control valve, For the function generator 15, it is possible to easily evaluate and adjust the setting value of the nonlinearity compensation function of the opening flow rate characteristic based on the test result in an actual machine.

The function possessed by the test device for the main steam control valve is that the test can be performed in the direction of opening from the initial opening during operation, and that any desired opening control signal 14 by the pressure control device can be used. It is possible to maintain the opening at an intermediate opening, and to return to the normal pressure control state safely and stably after the test is completed.

Further, since the main steam control valve test apparatus has an effective function at the initial startup of the nuclear power plant, the main steam control valve test apparatus is configured as an external device of the pressure control device which can be connected only during the test. It can be easily applied to the pressure control device having the same structure.

[0053]

As described above, according to the present invention, the evaluation test of the opening flow rate characteristic of the main steam control valve in the nuclear power plant is performed.
It can be easily evaluated in an output state of less than half of the rated output.

Further, the operation of evaluating and adjusting the set value of the function for compensating the non-linearity of the opening flow rate characteristic for each main steam control valve in the pressure control system is stopped at an early stage after the nuclear power plant construction. Since it can be carried out without doing so, there is an effect of avoiding a decrease in operating efficiency of the nuclear power plant.

[Brief description of drawings]

FIG. 1 is a block configuration diagram of a test apparatus for a main steam control valve according to an embodiment of the present invention.

FIG. 2 is a block configuration diagram of a boiling water nuclear power plant pressure control system.

FIG. 3 is a characteristic diagram of the opening flow rate of the main steam control valve.

FIG. 4 is a characteristic diagram of a function generator for compensating the opening flow rate non-linear characteristic of the main steam control valve.

FIG. 5 is a characteristic diagram of the main steam control valve flow rate with respect to the main steam flow rate request of the main steam control valve.

FIG. 6 is a block configuration diagram of a conventional main steam control valve testing device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Reactor, 2 ... Main steam piping, 3a-3d ... Main steam control valve, 4 ... Turbine, 5 ... Generator, 6 ... Condenser, 7 ... Water supply piping, 8 ... Pressure detector, 9 ... Main steam Pressure signal, 10 ... Pressure set value, 11, 23 ... Deviation calculator, 12 ... Main steam flow rate demand signal, 13 ... Pressure regulator, 14 ... Opening demand signal, 15 ... Function generator, 16 ... Control valve servo, 17 to 21 ... Characteristic curve, 22 ... Low value priority circuit, 24 ... Closing direction test bias signal, 25 ... Closing direction signal generator, 26 ... Opening feedback signal, 27 ... Opening direction test bias signal, 28 ... Opening direction signal Generator, 29 ... High price priority circuit.

Claims (4)

[Claims] 1. A controller for controlling steam pressure by means of a main steam control valve or the like inserted in a main steam pipe from a reactor to a turbine, compensating for a non-linear characteristic of an opening flow rate characteristic of the main steam control valve. The opening direction request signal and the control valve servo that controls the main steam control valve, the closing direction signal generator inputs the closing direction test bias signal to the low value priority circuit and the opening direction. A test device for a main steam control valve, comprising a test device comprising a high value priority circuit connected to an open direction signal generator that outputs a test bias signal and a deviation calculator. 2. An opening direction test bias signal is added to an opening request signal in a normal pressure control state for any one of a plurality of main steam control valves whose opening is normally controlled by an opening request signal of the same level. The method for testing a main steam control valve, characterized in that the opening degree of the main steam control valve is controlled to a fully open position and is held at an arbitrary opening by adding. 3. In a low power operation state of a nuclear power plant, a plurality of main steam control valves are sequentially driven to fully open positions to evaluate flow characteristics with respect to each opening and to compensate for non-linearity of opening flow characteristics. A method for testing a main steam control valve, characterized in that the setting of the function generator that performs the adjustment is performed. 4. A test method for a main steam control valve, characterized in that a test device for the main steam control valve is provided independently of the pressure control device, and is connected and used at every main steam control valve test.