JPH0540476Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to an automatic control system for the temperature of a nuclear reactor cooling system, and in particular, the invention relates to an automatic control system for the temperature of a nuclear reactor cooling system. This invention relates to an automatic reactor cooling system temperature control device that controls the system temperature using a main steam (MS) relief valve or a dump valve.

[Prior art] Conventionally, during heating and cooling in a PWR plant, the main steam (MS) relief valve or dump valve was manually operated to raise and cool the reactor cooling system (hereinafter referred to as RCS) during heating. The temperature was lowered over time, and the temperature was maintained at a predetermined temperature.

[Problems that the invention aims to solve] As described above, conventionally, the heating and cooling operations of RCS using MS relief valves or dump valves were performed manually; (2) Since it is a manual operation, the RCS temperature maintenance operation,
There were also other problems, such as the difficulty and time required to control the appropriate cooling rate.

[Means for solving the problem] Therefore, according to the present invention, a proportional-integral (PI) for RCS temperature control that directly controls the RCS temperature is provided.
Add arithmetic control logic, control the RCS temperature to the RCS temperature setpoint (Trcs−ref) by signals from the automation logic, and set the RCS temperature setpoint to:
Heating/cooling automation logic allows automatic changes, while manual operation allows
Provided is an automatic reactor cooling system temperature control device that eliminates the drawbacks of the conventional method of regulating the RCS temperature by adjusting the opening degree of the MS relief valve or dump valve to release main steam.

Specifically, according to the present invention, the steam pressure of the steam generator (S/G) is changed by adjusting the opening degree of the main steam relief valve or the dump valve to perform heating and cooling operations of the reactor cooling system. In such a reactor cooling system temperature control device, a proportional/integral calculation means is provided for inputting the deviation between the reactor cooling system temperature and a variable reactor cooling system temperature setting value to perform proportional/integral calculations. The reactor cooling system temperature is automatically heated and cooled by directly adjusting the valve openings of the main steam relief valve and the dump valve based on the output signal of the proportional/integral calculator. An automatic control device is provided.

[Function] By adding an RCS temperature control means and directly controlling the RCS temperature, the burden of operation and monitoring during heating and cooling can be significantly reduced, erroneous operations can be prevented, and the wasted time of operators can be reduced. It becomes possible to eliminate.

[Example] Hereinafter, an example of the present invention will be described with reference to the drawings. Figure 1 shows a system diagram of a well-known general nuclear reactor cooling system, where 1 is a steam generator, 2 is a reactor cooling pump (RCP), 3 is a reactor vessel, 4 is a pressurizer, and 5 is a reactor cooling system. is an MS relief valve, 6 is a dump valve, 7 is a pressurizer spray valve, 8 is a temperature measuring instrument for measuring the RCS temperature, and 9 is a pressurizer heater. In addition,
The temperature of the RCS is controlled by adjusting the valve opening of the MS relief valve 5 or dump valve 6, and the RCS pressure is controlled by adjusting the valve opening of the pressurizer spray valve 7 or turning on/off the proportional heater. Control takes place.

In Figure 1, RCS during conventional, heating, and cooling
When performing temperature control, heating and cooling are performed by manually adjusting the valve opening of the MS relief valve 5 or dump valve 6 based on instructions from the temperature measuring instrument 8.
As a result, the number of operations and monitoring is extremely large, which places a heavy burden on the operator.

In the present invention, by directly importing the RCS temperature into the control circuit using the temperature measuring instrument 8 and performing PI control, the MS relief valve 5 and dump valve 6 shown in FIG. 1 are automatically controlled to heat and cool the RCS. I'm trying to automate it. This allows RCS
It becomes possible to automatically control the temperature to any RCS temperature set value.

FIG. 2 conceptually shows a control circuit for an MS relief valve according to an embodiment of the present invention. In FIG. 2, on the left side is a first proportional/integral calculator, that is, a PI calculator PI ₁ On the right side, there is a second logic for heating control added by this invention.
PI calculator PI ₂ and third PI calculator PI ₃ for cooling control
Automation logic is shown including:

In the first PI calculator PI ₁ in the existing logic,
Terminal P has an analog input processing section from the steam generator.
An analog steam pressure signal is inputted via AI ₁ , and an analog S/G steam pressure set value is inputted from the controller, that is, the pressure adjustment converter 11, via the analog input processing unit AI ₂ to the terminal S. A digital automatic/manual (A/M) signal is input to terminal A via the digital input processing section DI, and terminal T
_The proportional and
An analog tracking signal to be taken into the PI calculator as an initial value at the start of integral (PI) calculation (start of automatic control) is input, and the terminal O
The calculation results from the PI calculator PI ₁ are sent to the signal switcher.
Output to SW ₁ .

Similarly, a second one for heating control in the automation logic
In the PI calculator PI ₂ , the deviation between the RCS temperature and the first RCS temperature set value Trcs-ref ₁ is input to the terminal D via an adder/subtractor, and the aforementioned automatic/manual signal is input to the terminal A. is input, the above-mentioned tracking signal is also input to the terminal T, and the calculation result of the PI calculator PI ₂ is input from the terminal O to the signal switcher.
Output to SW ₃ .

Finally, there is a third section for cooling control within the automation logic.
In the PI calculator PI ₃ , the deviation between the RCS temperature and the second RCS temperature set value Trcs-ref ₂ is input to terminal D via an adder/subtractor, and the automatic/manual signal is input to terminal A. A tracking signal is input to the terminal T, and the calculation result of the PI calculator PI ₃ is output from the terminal O to the signal switch SW ₅ .

When performing automatic heating control, the controller 11 is set to automatic, so that the controller 11 first converts the digitally represented automation signal from the digital input processing unit DI into the first, second, and third PI calculations. are applied to terminal A of devices PI ₁ , PI ₂ and PI ₃ respectively,
A signal from the automation logic side sets only the second PI calculator PI ₂ for heating control to the automatic control state. At the same time, a switch or signal changer
Apply the switching signal CH to SW ₁ , and switch the first PI at terminal n ₂ .
Instead of the signal from the arithmetic unit PI ₁ , the switch is switched so that the signal from the automation logic side at the terminal n ₁ is output to the terminal n ₀ . Furthermore, the switching signal CH is also applied to the switches SW ₃ , SW ₄ , SW ₅ , and SW ₆ in the automation logic, and the signal output from the output terminal O of the second PI calculator PI ₂ is applied to the switches SW ₃ , SW _{4 .} ,
The signal from _the automation logic side is supplied to _the controller ₁₁ via the analog output processing unit AO.
It will be given through.

Next, the RCS temperature and the first RCS temperature setting value Trcs− are applied to the terminal D of the second PI calculator PI ₂ .
Even if there is a deviation from ref ₁ , the second PI calculator PI ₂
PI calculation is performed, and the result of this calculation is sent from terminal O.
As mentioned above, the switches SW ₃ , SW ₄ , SW ₅ , SW ₆ ,
SW ₁ and the analog output processing unit AO to the controller 11, and further output to the MS relief valve 5 shown in FIG. 1 as a valve control signal via the manual pressure adjustment 12. This allows the MS relief valve 5 to adjust the RCS temperature to the first RCS temperature setting value.
An automatic control method is realized in which Trcs-ref ₁ is used for control. In addition, if the temperature is rising, the first RCS
The temperature set value Trcs-ref ₁ rises at a rate set by a setting device (not shown), and the MS relief valve 5 automatically adjusts the RCS temperature to the first RCS temperature set value. Control will be performed to follow Trcs-ref ₁ .

In addition, when maintaining the RCS temperature, the RCS temperature is automatically controlled by the MS relief valve by stopping the rise of the first RCS temperature set value Trcs-ref ₁ and keeping it at a constant value using a signal from the automation logic. Accordingly, the first RCS temperature setting value Trcs-ref ₁ is maintained and controlled.

When performing automatic cooling control, a third PI computing unit PI ₃ is used. That is, the switch SW ₅ in the automation logic is switched by the switching signal CH, and instead of the signal from the second PI calculator PI ₂ ,
A signal output from the output terminal O of the third PI computing unit PI ₃ is applied to the controller 11 via the switches SW ₅ , SW ₆ , SW ₁ and the analog output processing unit AO. The third PI calculator PI ₃ also performs PI calculation based on the deviation between the RCS temperature and the second RCS temperature set value Trcs−ref ₂ , which is applied to the terminal D. The setting value Trcs−ref ₂ is
When the temperature is decreasing, the temperature decreases at a rate set by a setting device (not shown). The calculation result of the third PI calculator PI ₃ is transferred from the terminal O to the switch SW ₅ as described above.
A controller 11 is provided through SW ₆ , SW ₁ and an analog output processing unit AO, and further a pressure manual adjustment 12 is provided.
MS as shown in Fig. 1 as a valve control signal via
This is output to the relief valve 5, whereby the MS relief valve 5 controls the RCS temperature to decrease.

FIG. 3 conceptually shows a dump valve control circuit according to an embodiment of the present invention. In FIG. 3, the existing logic including the fourth PI calculator PI ₄ is shown on the left side. On the right side, the automation logic added according to the invention is shown, including a fifth PI calculator PI ₅ for temperature control.

In the fourth PI calculator PI ₄ in the existing logic,
An analog main steam header pressure signal is input to terminal P via analog input processing unit _AI5 , and terminal S
An analog setting value is inputted from the controller, that is, the pressure adjustment converter 13, via the analog input processing unit AI ₆ , and the digital input processing unit is input to the terminal A.
An AND signal of a digital automatic/manual (A/M) signal given from the controller 13 via DI ₁ and a digital steam header mode signal given via the digital input processing section DI ₂ is input; Terminal T is used to start PI calculation (start automatic control)
should be taken into the PI calculator as the initial value of
The dump valve opening signal from the switch SW ₉ is input as a tracking signal, and the calculation result from the fourth PI calculator PI ₄ is output from the terminal O to the switch SW ₇ .

Similarly, the fifth PI operator in the automation logic
In PI ₅ , terminal D has the RCS temperature and the third
The deviation from the RCS temperature set value Trcs-ref ₃ is input via an adder/subtractor, the above-mentioned A/M signal, steam header mode signal and AND signal are input to terminal A, and the above-mentioned A/M signal and AND signal are input to terminal T. The dump valve opening signal of is input as a tracking signal, and the terminal O
From there, the calculation result of the PI calculator PI ₅ is output to the signal changer, that is, the switch SW ₁₀ .

When performing automatic temperature control using a dump valve, first set the controller 13 to automatic. In the steam header mode, a high potential signal is applied to the upper terminal of the AND circuit AND via _{the digital input processing section DI 2 .} The digitally represented high potential automatic signal is sent to the fourth and fifth PI calculators PI 4 and ₄ through the circuit AND.
The signal from the automation logic causes the fifth terminal for automatic temperature control to be applied to terminal A of PI ₅ .
Only the PI computing unit PI ₅ is set to the automatic control state, and an automation signal is also applied to the switch SW ₈ so that the switch SW ₈ passes the signal at the terminal n ₁ to the output terminal n ₀ . Further, the high potential signal from the digital input processing unit DI ₂ is also given to the switch SW ₉ as a switching signal, so that the switch SW ₉ can
In the steam header mode, the signals from the turbine trip controller and load reduction controller applied to terminal _n2 are cut off, and the signal at terminal _n1 is output to output terminal _n0 .

When the controller 13 is set to automatic, the switching signal CH is further applied to the switches SW ₇ , SW ₁₀ , and SW ₁₁ , and the output signal from the terminal O of the fifth PI calculator PI ₅ is applied to the switches SW _{10 .} , SW ₁₁ , SW ₇ and further through switches SW ₈ and SW ₉ , so that the output signal is passed through the switches SW 8 and SW 9.
It will be output as a dump valve opening signal from the output terminal _n0 of _SW9 .

Next, the RCS temperature and the third RCS temperature set value Trcs− are applied to the terminal D of the fifth PI calculator PI ₅ .
Even if there is a deviation from ref ₃ , the fifth PI calculator PI ₅
PI calculation is performed, and the result of this calculation is sent from terminal O.
As mentioned above, Switch SW ₁₀ , SW ₁₁ , SW ₇ ,
As a valve control signal via SW ₈ and SW ₉ , the first
It is output to the dump valve 6 shown in the figure. As a result, an automatic control method is realized in which the dump valve 6 controls the RCS temperature to the third RCS temperature setting value Trcs-ref ₃ .

[Effects of the invention] As described above, according to the invention, unlike conventional manual operation, an automatic control system is adopted during heating and cooling of a PWR plant, thereby significantly reducing the operating and monitoring burden on the operator. This has the effect of eliminating erroneous operations and further reducing time.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing a reactor cooling system to which an embodiment of the present invention can be applied; FIG. 2 is a circuit diagram showing a main steam relief valve control section according to an embodiment of the present invention;
FIG. 3 is a circuit diagram showing a dump valve control section according to an embodiment of the present invention. In the figure, 1 is a steam generator, 2 is a coolant pump, 3 is a reactor vessel, 4 is a pressurizer, 5 is a main steam relief valve, 6 is a dump valve, 7
is pressurizer spray valve, 8 is RCS temperature measuring device, 9 is
are pressurizer heaters, PI ₁ to PI ₅ are the first to fifth, respectively.
11 and 13 are controllers,
SW ₁ to SW ₁₁ are switches.

Claims (1)

[Scope of Claim for Utility Model Registration] To change the steam pressure of the steam generator (S/G) by adjusting the valve opening of the main steam relief valve or dump valve to perform heating and cooling operations of the reactor cooling system. In the reactor cooling system temperature control device, a proportional/integral calculation means is provided which performs proportional/integral calculations by inputting the deviation between the reactor cooling system temperature and the variable reactor cooling system temperature set value, and Automatic control of reactor cooling system temperature in which heating and cooling of the reactor cooling system is automatically performed by directly adjusting the valve openings of the main steam relief valve and the dump valve based on the output signal of the integral calculator. Device.