System and method for automatically setting main steam condensate drain valve closing setpoint of nuclear power plant

Abstract

The present invention relates to a system and a method for automatically setting a main steam condensate drain valve closing setpoint of a nuclear power plant, and, specifically, to a system and a method for automatically setting a main steam condensate drain valve closing setpoint of a nuclear power plant, which apply different setpoints to respective condensate drain valves since the pressure of main steam and a condenser of a nuclear power plant varies according to operating conditions such as turbine output, and the discharge speeds of the condensate vary according to the different installation positions of condensate drain valves.

Description

System and method for automatically setting the closing setting of the main steam condensate drain valve of a nuclear power plant

[0001] The present invention relates to a system and method for automatically setting the closing setting of a main steam drain valve of a nuclear power plant, and more particularly, to a system and method for automatically setting the closing setting of a main steam condensate drain valve of a nuclear power plant, which applies different settings to each condensate drain valve, since the main steam and condenser pressures of the nuclear power plant vary depending on the operating conditions such as turbine output, and the installation positions of the condensate drain valves vary, resulting in different condensate discharge rates.

[0002] In general, in the rapidly changing international energy environment, such as resource depletion, the enforcement of the Kyoto Protocol, and the surge in oil prices, the relative economic feasibility of new and renewable energy is becoming more advantageous, and the energy market based on new energy technologies such as hydrogen, fuel cells, and solar cells is expected to rapidly emerge as a huge industry that surpasses IT and BT. Accordingly, we have entered a global development competition system for the future new energy industry, and we need to prepare nationally to take the lead in the global market.

[0003] Nuclear power plants have been established as an important means of power generation, demonstrating superior operating performance compared to hydroelectric or thermal power plants in terms of economic feasibility, safety, and environmental conservation.

[0004] Nuclear power generation uses the energy generated during the nuclear fission process of fissile material to produce electricity. However, if an accident occurs in which radioactive materials generated during this process leak abnormally, there is a risk that it could develop into a large-scale disaster. Therefore, the safety of nuclear power plants has always been treated as a top priority.

[0005] Accordingly, although existing nuclear power plants are evaluated as having reasonable safety, the development of next-generation reactors with dramatically improved safety is actively underway worldwide.

[0006] Meanwhile, the main steam condensate drain valve of a nuclear power plant must send the condensate present in the pipe to the condenser without discharging the main steam.

[0007] During turbine output increases or fluctuations in a nuclear power plant, steam quality deteriorates, requiring rapid condensate discharge to protect the turbine.

[0008] However, frequent operation of the drain valve to drain condensate may cause the condensate drain valve to fail.

[0009] Additionally, if the setting for condensate discharge is not appropriate, the main steam may be discharged to the condenser through the condensate drain pipe, which may cause the water level transmitter to fail and the power plant efficiency to decrease.

[0010] In this way, the main steam and condenser pressures of nuclear power plants differ depending on the operating conditions such as turbine output, and the installation locations of the condensate drain valves are different, so the speed at which condensate is discharged is different, so different settings are required for each condensate drain valve.

[0011]

[0012] The technical problem to be achieved by the present invention is to improve the conventional problems, and since the main steam and condenser pressures of a nuclear power plant are different depending on the operating conditions such as turbine output and the installation positions of the condensate drain valves are different, and the speed at which condensate is discharged is different, it is to provide a system and method for automatically setting the closing setting of a main steam drain valve of a nuclear power plant, which applies different settings to each condensate drain valve.

[0013] A method for automatically setting the closing setting of a main steam condensate drain valve of a nuclear power plant according to the features of the present invention to solve these problems is as follows:

[0014] Step (S205) where the control unit determines whether it is the first operation;

[0015] If it is the first operation, the step (S210) of setting the closing setpoint low (S2) of the main steam condensate drain valve of the nuclear power plant to 50%;

[0016] After waiting for a certain period of time (S211), the control unit determines whether the level of the condensate has reached the set level (S1) (S212);

[0017] When the condensate level reaches the setpoint high level (S1), the control unit calculates the slope value (A1) by calculating the water level and time from 100 to 50% based on the setpoint high value (S1) (S213);

[0018] Step (S214, S215) in which the above control unit calculates the valve closing time (T1) and the slope of the water level at closing (A2);

[0019] Step (S216) in which the above control unit calculates the set point (S2) using the valve closing time (T1) and the slope of the water level (A2);

[0020] After the first operation is completed, the control unit waits for a certain period of time (S220), and then determines whether the condensate level has reached the set level (S1) (S221);

[0021] When the condensate level reaches the set level (S1), the control unit calculates the water level change slope (A3) from 100 to 80% (S222);

[0022] A step (S223) in which the above control unit compares the water level change slope (A3) with the water level change slope (A1) from 100 to 50% to determine whether the allowable error (state change) is exceeded;

[0023] If the difference between the water level change slope (A3) and the water level change slope (A1) exceeds the allowable error, the control unit repeats the process from the step (S210) to recalculate the set value (S2).

[0024] If the difference between the water level change slope (A3) and the water level change slope (A1) is within the allowable error, the step (S224) of measuring the water level (L1) when the control unit closes the valve;

[0025] Step (S225) in which the above control unit determines whether the difference between the water level (L1) and the target value (O) when the valve is closed is 10% or less;

[0026] If the difference between the water level (L1) and the target value (O) when the valve is closed is less than 10%, the control unit performs the process from the step (S220), and if the difference between the water level (L1) and the target value (O) when the valve is closed is more than 10%, the control unit calculates the ratio of the water level (L1) and the target value (O) when the valve is closed and corrects the correction value (C) (S226), and performs the process again from the step (S220).

[0027] The above control unit determines the driving method based on the driver's manual / automatic driving selection.

[0028] The above control unit checks the input value and, if the value is not permitted, performs manual operation mode.

[0029] Another feature of the present invention for solving these problems is an automatic setting system for the closing setting of the main steam condensate drain valve of a nuclear power plant,

[0030] Input section for receiving driver's selection;

[0031] A water level detection unit that detects the water level of condensate;

[0032] A water level transmitter that transmits the water level of the condensate detected by the above water level detection unit;

[0033] A control unit is included that determines manual or automatic operation according to the selection of the above input unit, receives the level of condensate from the level transmitter, and controls the main steam condensate to be discharged to the condenser through the condensate drain pipe when the level of the condensate reaches the set value for condensate discharge by referring to the timer, and the control unit executes the above method.

[0034]

[0035] According to one embodiment, since the main steam and condenser pressures of a nuclear power plant differ depending on the operating conditions such as turbine output, and the installation positions of condensate drain valves differ, resulting in different condensate discharge rates, a system and method for automatically setting the closing settings of a main steam condensate drain valve of a nuclear power plant can be provided, which applies different settings to each condensate drain valve.

[0036] Figure 1 is a schematic diagram of a system for automatically setting the closing setting of a main steam condensate drain valve of a nuclear power plant according to an embodiment of the present invention.

[0037] FIG. 2 is a drawing showing a method for automatically setting the closing setting of a main steam condensate drain valve of a nuclear power plant according to an embodiment of the present invention.

[0038] FIG. 3 is a drawing schematically showing actual water level changes for explaining a method for automatically setting the closing setting value of a main steam condensate drain valve of a nuclear power plant according to an embodiment of the present invention.

[0039] FIG. 4 is a drawing showing in detail an example of an actual water level change for explaining a method for automatically setting a closing setting value of a main steam condensate drain valve of a nuclear power plant according to an embodiment of the present invention.

[0040] Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings so that those skilled in the art can easily implement the present invention. The present invention may be implemented in various different forms and is not limited to the embodiments described herein.

[0041] Additionally, throughout the specification, whenever a part is said to "include" a component, this does not mean that it excludes other components, but rather that it may include other components, unless otherwise specifically stated.

[0042] Figure 1 is a schematic diagram of a system for automatically setting the closing setting of a main steam condensate drain valve of a nuclear power plant according to an embodiment of the present invention.

[0043] Referring to FIG. 1, the automatic setting system for the main steam condensate drain valve closing setting of a nuclear power plant according to an embodiment of the present invention is

[0044] An input section (110) for receiving the driver's selection;

[0045] A water level detection unit (120) that detects the water level of condensate;

[0046] A water level transmitter (130) that transmits the water level of the condensate detected by the water level detection unit;

[0047] A timer (150) to check the time;

[0048] A control unit (140) is included that determines manual or automatic operation according to the selection of the input unit (110), receives the level of condensate from the level transmitter, and controls the discharge of main steam condensate to a condenser through a condensate drain pipe when the level of condensate reaches a set value for condensate discharge by referring to the timer (150), and the control unit (140) executes a method for automatically setting a closing set value of a main steam condensate drain valve of a nuclear power plant according to an embodiment of the present invention.

[0049] The operation of the automatic setting system for the main steam condensate drain valve closing setting of a nuclear power plant according to an embodiment of the present invention having such a configuration is described as follows.

[0050] FIG. 2 is a drawing showing a method for automatically setting a closing setpoint of a main steam drain valve of a nuclear power plant according to an embodiment of the present invention, FIG. 3 is a drawing schematically showing an actual water level change for explaining a method for automatically setting a closing setpoint of a main steam condensate drain valve of a nuclear power plant according to an embodiment of the present invention, and FIG. 4 is a drawing showing in detail an example of an actual water level change for explaining a method for automatically setting a closing setpoint of a main steam condensate drain valve of a nuclear power plant according to an embodiment of the present invention.

[0051] Referring to Fig. 2, when the driver first selects automatic driving or manual driving using the input unit (110), the control unit (140) determines the driving method based on the driver's selection of manual / automatic driving (S201).

[0052] When manual driving is selected, the control unit (140) performs manual driving mode, and the driver drives manually (S204).

[0053] When automatic driving is selected, the control unit (140) checks the input value (S202).

[0054] The above control unit (140) checks the input value and, if it is an unacceptable value, performs manual driving mode (S204), and if it is an acceptable value, performs automatic driving mode (S203).

[0055] When automatic driving starts, the control unit (140) performs a step (S205) of determining whether it is the first operation.

[0056] If it is the first operation, the control unit (140) performs a step (S210) of setting the main steam condensate drain valve closing setting value of the nuclear power plant (S2) to 50%.

[0057] After waiting for a certain period of time (S211), the control unit (140) performs a step (S212) of determining whether the condensate level has reached the set level (S1).

[0058] When the condensate level reaches the set point high (S1) level, the control unit (140) calculates the level and time from 100 to 50% based on the set point high (S1) value to calculate the slope value (A1) (S213).

[0059] Next, the control unit (140) performs steps (S214, S215) of calculating the valve closing time (T1) and the slope of the water level (A2) at closing.

[0060] Next, the control unit (140) performs a step (S216) of calculating the set value (S2) using the valve closing time (T1) and the slope of the water level (A2).

[0061] After the first operation is completed, the control unit (140) waits for a certain period of time (S220) and then performs a step (S221) of determining whether the condensate level has reached the set level (S1).

[0062] Next, when the condensate level reaches the set level (S1), the control unit (140) performs a step (S222) of calculating the water level change slope (A3) from 100 to 80%.

[0063] Next, the control unit (140) performs a step (S223) of comparing the water level change slope (A3) with the water level change slope (A1) from 100 to 50% to determine whether the allowable error (state change) is exceeded.

[0064] Next, if the difference between the water level change slope (A3) and the water level change slope (A1) exceeds the allowable error, the control unit (140) repeats the process from the step (S210) to recalculate the set value (S2).

[0065] If the difference between the water level change slope (A3) and the water level change slope (A1) is within the allowable error, the control unit (140) performs the step (S224) of measuring the water level (L1) when the valve is closed.

[0066] Next, the control unit (140) performs a step (S225) of determining whether the difference between the water level (L1) and the target value (O) when the valve is closed is 10% or less.

[0067] If the difference between the water level (L1) and the target value (O) when the valve is closed is less than 10%, the control unit (140) performs the step (S220) above, and if the difference between the water level (L1) and the target value (O) when the valve is closed is more than 10%, the control unit (140) calculates the ratio of the water level (L1) and the target value (O) when the valve is closed, modifies the correction value (C) (S226), and performs the step of performing the step (S220) again.

[0068] The actual water level change is as shown in Figure 3.

[0069] Referring to Figure 3, the water level decreases in a linear structure from when the valve is opened until when the valve is closed.

[0070] An example of calculation according to actual water level change is shown in Figure 4.

[0071] Referring to Fig. 4, in the step (S213) of calculating the slope value (A1) by calculating the water level and time from 100 to 50%, A1 = 47.5%-76% / tm = -9.5% / sec.

[0072] Additionally, the valve closing time T1 is 2.5 sec.

[0073] And, when the valve is closed, the slope A2 = -11% / 2.5sec = -4.4% / sec.

[0074] Also, the set point (S2) = target value - A2*T1 = 15%. Here, the target value is 4%.

[0075] And the actual closing slope A3 = -17% / 2.5sec = -6.8% / sec.

[0076] And the correction value C = 1+ (6.8-4.4) / 4.4 = 1.55.

[0077] Also, A2 = A2*correction value = -4.4% / sec*1.55 = -6.8% / sec.

[0078] And S2 = target value - A2 - T1 = 21%.

[0079] According to one embodiment, since the main steam and condenser pressures of a nuclear power plant vary depending on operating conditions such as turbine output and the installation locations of condensate drain valves vary, the speed at which condensate is discharged varies, different settings can be applied to each condensate drain valve.

[0080] Although the embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements made by those skilled in the art using the basic concept of the present invention defined in the following claims also fall within the scope of the present invention.

Claims

1. Step for determining whether the control unit is the first operation (S205); If it is the first operation, the step (S210) of setting the closing setpoint low (S2) of the main steam condensate drain valve of the nuclear power plant to 50%; After waiting for a certain period of time (S211), the control unit determines whether the condensate level has reached the set level (S1) (S212); When the condensate level reaches the setpoint high level (S1), the control unit calculates the slope value (A1) by calculating the water level and time from 100 to 50% based on the setpoint high value (S1) (S213); Step (S214, S215) in which the above control unit calculates the valve closing time (T1) and the slope of the water level at closing (A2); A method for automatically setting the closing setpoint of a main steam condensate drain valve of a nuclear power plant, comprising a step (S216) in which the control unit calculates the setpoint low (S2) using the valve closing time (T1) and the slope of the water level (A2).

2. In paragraph 1, After the first operation is completed, the control unit waits for a certain period of time (S220), and then determines whether the condensate level has reached the set level (S1) (S221); When the condensate level reaches the set level (S1), the control unit calculates the water level change slope (A3) from 100 to 80% (S222); A step (S223) in which the above control unit compares the water level change slope (A3) with the water level change slope (A1) from 100 to 50% to determine whether the allowable error (state change) is exceeded; If the difference between the water level change slope (A3) and the water level change slope (A1) exceeds the allowable error, the control unit repeats the process from the step (S210) to recalculate the set value (S2). If the difference between the water level change slope (A3) and the water level change slope (A1) is within the allowable error, the step (S224) of measuring the water level (L1) when the control unit closes the valve; Step (S225) in which the above control unit determines whether the difference between the water level (L1) and the target value (O) when the valve is closed is 10% or less; A method for automatically setting a main steam condensate drain valve closing setpoint of a nuclear power plant, further comprising a step in which, if the difference between the water level (L1) and the target value (O) when the valve is closed is less than 10%, the control unit performs from the step (S220), and if the difference between the water level (L1) and the target value (O) when the valve is closed is more than 10%, the control unit calculates the ratio of the water level (L1) and the target value (O) when the valve is closed and corrects the correction value (C) (S226), and performs again from the step (S220).

3. In paragraph 2, The above control unit is a method for automatically setting the closing setting value of a main steam condensate drain valve of a nuclear power plant, which determines the operation method by selecting manual / automatic operation of the operator.

4. In paragraph 3, A method for automatically setting the closing setting value of a main steam condensate drain valve of a nuclear power plant, wherein the above control unit checks the input value and, if the value is not permitted, performs manual operation mode.

5. Input section for receiving driver's selection; A water level detection unit that detects the water level of condensate; A water level transmitter that transmits the water level of the condensate detected by the above water level detection unit; A system for automatically setting the closing setpoint of a main steam condensate drain valve of a nuclear power plant, comprising a control unit that determines manual or automatic operation based on the selection of the input unit, receives the level of condensate from the level transmitter, and controls the discharge of main steam condensate to a condenser through a condensate drain pipe when the level of condensate reaches a set point for condensate discharge by referring to the timer, wherein the control unit executes the method of any one of claims 1 to 4.

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