JPH01314998A - Apparatus and method for controlling output of nuclear reactor - Google Patents

Abstract

PURPOSE:To enable accurate output control for a nuclear power plant automatically by performing an inspection and compensation of a deviation between a target setting output signal and an output signal of a generator while being compared with a preset value to control. CONSTITUTION:An output set value Pr set with an output setter 22 and a power signal Pg detected 11 from a generator 10 driven with a steam turbine 9 using a steam generated in a nuclear reactor are inputted into a core flow rate controller 21. Then, a deviation between the value and the signal is detected and a speed control signal so provided to make the deviation down to zero is outputted to a pump power source device 6 to change a flow rate of a core. The flow rate of the core is detected 7 and a core flow rate signal Fc is inputted into the device 21 to be compared with preset upper and lower limit values of the core flow rate and a rated value to output a signal corresponding the results to a control rod drive controller 23. The device 23 outputs an insertion/ withdrawal command for a control rod 3 to a control rod driving mechanism 4 and the device 21.

Description

Detailed Description of the Invention "Objective of the Invention" (Industrial Application Field) The present invention provides reactor power control in a nuclear power plant, in particular control rod operation and core flow rate that are automatically controlled according to a set power change pattern, etc. This article relates to a nuclear reactor power control device and its control method.

(Prior art) In a boiling water reactor in which steam is obtained by boiling coolant in the reactor, conventional methods involve inserting and withdrawing control rods into the reactor core and adjusting the flow rate of coolant in the core. This adjusts the reactor's output. That is, when the control rod drive mechanism is operated and the control rod is inserted into the reactor core, the output of the reactor decreases 1, and when the control rod is withdrawn, the output increases. Furthermore, by changing the rotational speed of the coolant pump and increasing the core flow rate, the output increases, and by decreasing the flow rate, the output decreases.

By controlling the amount of steam generated, the output power of the generator was adjusted.

(Problem to be solved by the invention) Conventionally, when adjusting the output, the control rods and the reactor core flow rate were controlled individually and were generally adjusted manually by operators. The decision on which flow rate to adjust was left to the operator's discretion.However, in general, reactor output adjustment using control rods has a large output change with respect to the control rod operation amount, but the response is slow, and the control rods have a slow response. Although the response is fast, it is difficult to obtain a large output change such as when starting and stopping.For this reason, in order to coordinate control rod operation and flow rate control, especially according to a set signal of a predetermined output change pattern, it is necessary to It is necessary to repeatedly start and stop the control rod drive mechanism, which not only requires a wealth of experience and a great deal of effort from the operator, but also
It has been extremely difficult to accurately match a predetermined output change pattern.

The present invention has been made in view of the above circumstances, and its purpose is to adjust the core flow rate in accordance with a predetermined output setting signal, and to adjust the flow rate between the control rods and the core within the predetermined adjustment range. An object of the present invention is to provide a nuclear reactor power control device and a control method thereof, which can coordinately and automatically control the power generators and precisely adjust the generator output.

[Structure of the Invention] (Means for Solving the Problems) A nuclear reactor including a control rod drive mechanism for inserting and extracting control rods and a pump drive device for controlling the speed of a cooling water pump for circulating cooling water in the reactor core, and the aforementioned nuclear reactor. In a nuclear power plant consisting of a steam turbine and a generator driven by steam generated from a reactor, an output setting device that sets a target output;
A deviation between the set output signal of the output setting device and the output signal of the generator is detected and a control signal for the cooling water flow rate of the core is outputted to compensate for the deviation, and the rated value and upper limit value of the core flow rate are preset. and a core flow rate control device that sets a lower limit value and outputs a comparison signal with the core flow rate signal, and inputs the comparison signal to control withdrawal of control rods when the core flow rate is larger than the set value, and control when the core flow rate is smaller than the set value. It is equipped with a control rod control device that outputs a rod insertion command signal.

(Function) Detects the deviation between the output setting value and the generator output signal, outputs a speed control signal that makes this deviation zero to the cooling water pump drive device, changes the core flow rate, and adjusts the reactor output and power generation. In addition to controlling the machine power to match the set value, if the core flow rate falls outside the preset flow rate range, control rods are inserted or withdrawn, and the resulting fluctuations in output are also controlled by the core flow rate. automatically within a predetermined flow rate range.

(Example) An example of the present invention will be described with reference to the drawings. FIG. 1 is a configuration diagram, in which a reactor core 2 is installed in a nuclear reactor 1, and a control rod 3 for adjusting reactor power is provided in this core 2. A control rod drive mechanism 4 for inserting and withdrawing the control rods 3 is installed outside the reactor 1 and is powered by high pressure water or an electric motor. In addition, the reactor 1 is equipped with a plurality of coolant pumps 5, which are installed internally or externally and connected to the reactor 1 through piping, and are driven by a pump power supply device 6 to adjust the rotation speed. Change core flow rate. Note that this core flow rate is detected by a core flow rate detector 7. A main steam pipe 8 serving as a main steam passage is connected to a steam turbine 9 in the upper part of the nuclear reactor 1, and a generator 10 is directly connected to the steam turbine 9. Steam generated in the nuclear reactor 1 rotates a steam turbine 9 and drives a generator 10. The power generation output of the generator 10 is detected by a power detector 11 and transmitted to the core flow rate control device 21 as a power signal Pg. Also, the output setting device 2
2 has set values such as the output change pattern of the generator 10 which is a control target set in advance, and outputs the output set value Pr to the core flow rate control device 21. The core flow rate control device 21 outputs to the pump power supply device 6 a speed control signal that is a flow rate control signal that makes the deviation between the power signal Pg and the output setting value Pr zero. The core flow rate control device 21 also has a core flow rate signal Fc from the core flow rate detector 7.
is also input. The core flow rate control device 21 has a lower limit value F [, an upper limit value Fu, and a rated value FO of allowable core flow rate set in advance, and compares it with the core flow rate signal Fc to determine that the core flow rate is at the lower limit value PL. The signal 31 indicating the upper limit value Fu
A signal 32 indicating that the core flow rate is below the rated value, a signal 33 indicating that the core flow rate is below the rated value, and a signal 34 indicating that the core flow rate is above the rated value are output to the control rod drive control device 23. This control rod drive control device 23 sends insertion and withdrawal command signals for the control rods 3 to the control rod drive mechanism 4 and the core flow rate control device 2.
Output to 1.

In the configuration of the embodiment, the core flow rate detector 7 may be a speed detector (not shown) of the coolant pump 5 or a pump power supply device if the characteristics between the coolant pump 5 and the core flow rate are clear. Similar effects can be obtained by replacing the output frequency detector 6 with an isometric signal generator (also not shown).Next, the operation of the above configuration will be explained. Note that there are some differences in the control methods used when increasing the output of a nuclear power plant and when decreasing the output. Further, whether the output increases or decreases is determined by the output change pattern, which is a setting value set in the output setting device 22.

First, the time when the output increases will be explained. Figure 2 is a flowchart when the output increases. Step A...The core flow rate control device 21 is the power detector 1.
The power signal Pg, which is the generator output from the generator 1, and the output setting value Pr from the output setting device 22 are input, and a speed control signal such that the deviation thereof becomes zero is output to the pump power supply device 6. The pump power supply device 6 changes the speed of the coolant pump 5 in response to this speed control signal to change the core flow rate. Changes in core flow rate change reactor output and the amount of steam generated changes.

This change in the amount of generated steam changes the driving force of the steam turbine 9 and changes the power generation output of the generator 10. This power generation output becomes the power signal Pg'h of the power detector 11, which is fed back to the core flow rate control device 21, and is finally controlled so that Pg=Pr. In this process, the flow rate of the coolant flowing through the reactor core 2 (core flow rate) is
Detected by the core flow rate detector 7, the core flow rate signal Fc
It is output to the core flow rate control device 21 as a.

Step B...In the process of step A above, the core flow rate control device 21 compares the input core flow rate signal Fc with the allowable core flow rate lower limit value FL, and if Fc≦FL, the core flow rate is Fc= Coolant pump 5 so that it is FL
At the same time, it outputs a signal 31 to the control rod drive control device 23 indicating that the core flow rate is the lower limit value F[. This is a case where the power signal Pg, which is the power generation output of the generator 10, is larger than the output setting value Pr. The control rod drive control device 23 outputs an insertion command signal to the control rod drive mechanism 4 to insert the control rod 3 into the reactor core 2 while the signal 31 is input. By inserting the control rods 3, the output of the reactor 1, that is, the power generation output of the generator 10, decreases, and the core flow rate is controlled in accordance with the movement of the control rods 3. The core flow rate control device 21 increases the core flow rate to compensate for the decrease in output due to the insertion of the control rods 3, and resets the signal 31 when Fc>FL, and the control rod drive control device 23 performs control. The control rod 3 insertion command signal to the rod drive machine 1114 is stopped, and the control rod 3 is stopped.

As described above, the core flow rate (Fc) is controlled so that the power generation output (Pg) of the generator 10 is equal to the output setting value Pr when the core flow rate (Fc) is equal to or higher than the allowable lower limit value FL. Although not shown, a dead band ε is provided for the condition Fc>FL for resetting the signal 31 to prevent hunting, and Fc
>FL+ε is easily possible.

Step C...Also, in the process of step A,
The core flow rate control device 21 compares the input core flow rate signal Fc with the allowable upper limit value Fu of the core flow rate, and if Fc≧Fu, the speed of the coolant pump 5 is adjusted so that the core flow rate becomes Fc=Fu. In addition to controlling the control rod drive control device 23
In contrast, a signal 32 indicating that the core flow rate is at the upper limit value is output.

This is a case where the power signal Pg, which is the power generation output of the generator 10, is smaller than the output setting value Pr. The control rod drive control device 23 outputs a withdrawal command signal to the control rod drive mechanism 4 to withdraw the control rod 3 while the signal 32 is being input. As a result, the power generation output of the generator 10 increases, and after the power signal Pg becomes equal to the output setting value Pr, the core flow rate control device 21 decreases the core flow rate to compensate for the increase in output due to the withdrawal of the control rods 3. Then, when Fc<Fu, the signal 32 is reset, and the control rod drive control device 23 stops sending a command signal to the control rod drive mechanism 4 to withdraw the control rod 3. As described above, the core flow rate (Fc)
is controlled so that the power generation output (Pg) of the generator 10 is equal to the output setting value Pr when the power generation output (Pg) is less than or equal to the allowable upper limit value Fu. Note that, similarly to step B, a dead band ε is provided for the condition Fc<Fu for resetting the signal 32, so that Fc<FL−
It is easy to set ε.

Step D...Furthermore, in the process of Step A above, the core flow rate (Fc) is set to a lower limit value FL and an upper limit value F.
u, the core flow rate control device 21 first determines that the deviation between the power signal Pg of the generator 10 and the output setting value Pr of the output setting device 22 is zero, as explained in the process of step A above. A speed control signal is output to the pump power supply device 6 so that

The core flow rate at this time is detected by the core flow rate detector 7 and inputted to the core flow rate control device 21 as a core flow rate signal Fc. This core flow rate control device 21 compares the core flow rate signal Fc at this time with the rated value FO of the core flow rate, and
c>Fo+ΔF, a signal 34 indicating that the core flow rate is larger than the rated value Fo is sent to the control rod drive controller 23.
Output to. Here, ΔF is a dead band ε for giving hysteresis to the control and preventing hunting from occurring in the adjustment control. The control rod drive control device 23 causes the control rod drive mechanism 4 and the core flow rate control device 21 to withdraw the control rods 3 while the signal 34 indicating that the core flow rate is larger than the rated value is input. Outputs a command signal.

By pulling out the control rod 3, the power output of the generator 10 (P
g) increases, and to compensate for this, the core flow rate control device 21 controls the core flow rate to decrease as described in step A above, and while the control rod 3 withdrawal command signal continues to be input, the core flow rate control device 21 decreases the core flow rate signal. When Fc becomes Fc=Fo, the signal 34 is reset, and the control rod drive control device 23 stops sending the withdrawal command signal to the control rod drive mechanism 4. As described above, the core flow rate (Fc) is adjusted to the rated value Fo.
>Fo+ΔF, the control rod 3 is pulled out so that Fc≦Fo. In addition, the rated value F of the core flow rate
o and the dead band ΔF may be constants or may be variable as a function of the output setting value Pr from the output setting device 22.

Next, the time when the output drops will be explained with reference to the flowchart when the output drops shown in FIG. Regarding the process of step A", step A when the output increases in the above-mentioned figure 2.
, and step B° is the step C1 and step C described above.

Since step B is the same as step B above, the explanation will be omitted. However, step D'' is different from step D described above when the core flow rate is between the allowable lower limit value F[ and upper limit value Fu, so step D° will be described below.

Step D - First, as described in the process of step A above, the core flow rate control device 21 detects the difference between the power signal pg, which is the generated output from the generator 10, and the output setting value Pr from the output setting device 22. A speed control signal is output to the pump power supply device 6 that drives the coolant pump 5 so that the speed becomes zero. The core flow rate at this time is detected by the core flow rate detector 7,
The core flow rate signal Fc which is this output is the core flow rate control device 2.
1 is input. The core flow rate control device 21 compares the input core flow rate signal Fc with the rated value F○ of the core flow rate.
When Fc<Fo−ΔF, a symbol 33 indicating that the core flow rate is smaller than the rated value Fo is displayed in the control rod drive controller 23.
Output to. Here, ΔF is a dead band for providing hysteresis in the control, as in the case of increasing the output.

At this time, the control rod drive controller 23 receives the core flow rate signal F.
While the signal 33 indicating that c is smaller than the rated value FO is input, an insertion command signal for inserting the control rod 3 into the reactor core 2 is output to the control rod drive machine 1114 and the core flow rate control device 21. By inserting the control rods 3 into the reactor core 2, the reactor output (
Pg) decreases, and to compensate for this, the core flow rate control device 21 controls the core flow rate to increase as described in step A above, and while the insertion command signal continues to be input, F
When c≧Fo, the control rod drive control device 23 resets the signal 33 and stops issuing the control rod 3 insertion command signal to the control rod drive mechanism 4.

As described above, when the core flow rate (Fc) becomes Fc<Fo−ΔF with respect to the rated value FO of the core flow rate, F
The control rod 3 is inserted so that c≧Fo.

Note that the rated value Fo and dead band ΔF of the core flow rate may be constants or may be variable as a function of the output setting value Pr from the output setting device 22. The same is true for rising.

[Effects of the Invention] According to the present invention, while controlling the core flow rate between the upper limit and the lower limit allowed for the operation of the reactor, accuracy is maintained with respect to set values such as a preset generator output change pattern. In addition to controlling the control rods so that they match well, the output control by the control rods, which have slow operating times and large output changes relative to the amount of operation, is finely compensated for by fast-response coolant core flow control. Utilizing the characteristics of core flow control and coordinating these functions at the same time, it is possible to automatically control the output of a nuclear power plant with high accuracy without bothering operators, improving its operational efficiency and reliability. Effective for improvement.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of the present invention, FIG. 2 is a flowchart when the output increases, and FIG. 3 is a flowchart when the output decreases. 1...: Nuclear reactor 2... Core 3... Control rod 4... Control rod drive mechanism 5... Recirculation pump 6... Pump power supply device 7... Core flow rate detector 9. ...Kiln air turbine 10...Generator 11...
Power detector 21...Core flow rate control device 22...Output setting device 23...Control rod drive control device.

Claims (2)

[Claims] (1) A nuclear reactor equipped with a control rod drive mechanism that inserts and removes control rods in the reactor core and a pump drive device that controls the speed of a cooling water pump that circulates cooling water in the reactor core, and steam generated from the reactor. In a nuclear power plant consisting of a driven steam turbine and a generator driven by the steam turbine, an output setting device that sets a target output, and a deviation between a set output signal of this output setting device and an output signal of the generator A core flow rate that outputs a control signal for the cooling water flow rate of the core to detect and compensate for this, and also sets the rated value, upper limit value, and lower limit value of the core flow rate in advance and outputs a comparison signal with the core flow rate signal. and a control rod control device which inputs a comparison signal from the core flow rate control device and outputs a control rod withdrawal command signal when the core flow rate is larger than the set value, and a control rod insertion command signal when the core flow rate is smaller than the set value. A nuclear reactor power control device characterized by comprising: (2) Input the output setting signal from the output setting device that has set the target output and the power signal from the generator into the core flow control device, and pump the core flow control signal such that the deviation between the two signals is zero. In addition to outputting the output to the power supply device, the pump power supply device adjusts the speed of the cooling water pump according to the input core flow rate control signal, and changes the core flow rate so that the output setting signal and the power signal of the generator match. Control output. Furthermore, the core flow rate signal is input to the core flow rate control device and compared with the preset flow rate settings of the lower limit value, upper limit value, and rated value of the core flow rate. Above the upper limit value and between the lower limit value and the upper limit value, the respective comparison signals are output to the control rod control device at the rated value or above, and while the comparison signal below the lower limit value is input to the control rod control device, the control rod is When the insertion command signal is greater than the upper limit value or the comparison signal is greater than the rated value, a control rod withdrawal command signal is output to the control rod drive mechanism to operate the control rod. In addition, the control rod insertion command signal is stopped when the core flow rate exceeds the lower limit value, and the control rod withdrawal command signal is stopped when the core flow rate decreases below the upper limit value, is equal to the rated value, or decreases, and the control rod operation is stopped. Stop. Note that during power reduction, when the core flow rate is between the lower limit value and the upper limit value, if the core flow rate is below the rated value, a comparison signal is output from the core flow rate control device to the control rod control device, and the control rod control device outputs a comparison signal to the control rod control device. An insertion command signal is output to the control rod drive mechanism. In addition, if a mismatch between the output setting signal and the generator power signal remains after the control rod operation is stopped, the core flow control device sends the core flow control signal to the pump so that the deviation between the output setting signal and the power signal becomes zero. A nuclear reactor power control method characterized by outputting power to a power supply device, adjusting core flow rate, and performing cooperative control with control rod operation.