A control system and method for a nuclear power plant waste fluid discharge pump start-up sequence

Abstract

The application discloses a kind of nuclear power plant waste liquid discharge pump starting sequence control system and method, the system includes liquid level measuring device, electric control device and three waste liquid discharge pumps, the liquid level measuring device is used to detect the liquid level height of waste water in waste liquid pit, the electric control device includes three logic control modules, the three logic control modules are connected with the liquid level measuring device, the logic control module is used to output control instruction according to the liquid level height, the three waste liquid discharge pumps are connected with respective corresponding logic control module, and the waste liquid discharge pump is used to execute corresponding operation according to the control instruction. By the system, the first waste liquid discharge pump to be started, the starting sequence of multiple waste liquid discharge pumps and the corresponding starting conditions can be determined, which can well solve the problem of uneven use of pumps caused by fixed starting sequence and conditions of pumps, and is beneficial to prolong the service life of equipment.

Description

Technical Field

[0001] The present invention relates to the technical field of nuclear power plant waste liquid pump control, and in particular to a control system and method for a starting sequence of a nuclear power plant waste liquid discharge pump. Background Art

[0002] The conventional island steam turbine building of a nuclear power plant is equipped with a seawater pit to collect waste liquid. The seawater pit is one type of waste liquid pit, and the seawater pump in the seawater pit is one type of waste liquid discharge pump. Generally speaking, the seawater pit is equipped with three seawater drainage pumps, and the pit is set to four liquid level values: low, high 1, high 2, and high 3. The liquid levels are ranked from low to high as high as high 1, high 2, and high 3. When the liquid level reaches high 1, one pump is started. High 2 starts the second pump (starting two pumps at the same time). High 3 starts the third pump (starting all three pumps at the same time), and the low liquid level stops the pumps. Typically, the starting conditions for each pump are fixed, and the logic design is simple and clear. However, this can cause some pumps to be started frequently while others are used less frequently, resulting in uneven pump utilization and a certain impact on equipment life.

[0003] Existing patent CN107806407A discloses a liquid level control system and method for a circulating water pump pit in a nuclear power plant. The system includes: a main submersible sewage pump with a first liquid level switch and a backup submersible sewage pump with a second liquid level switch. The first liquid level switch is configured to activate the main submersible sewage pump when the liquid level in the pump pit is greater than or equal to a second liquid level, or to shut down the main submersible sewage pump when the liquid level in the pump pit is less than or equal to a first liquid level, where the second liquid level is greater than the first liquid level; the second liquid level switch is configured to activate the backup submersible sewage pump when the liquid level in the pump pit is greater than or equal to a fourth liquid level, or to shut down the backup submersible sewage pump when the liquid level in the pump pit is less than or equal to a third liquid level, where the third liquid level is less than the fourth liquid level and greater than the second liquid level. The system controls the liquid level in the pump pit by designing multiple gears to ensure the normal operation of the circulating water pump.

[0004] Existing patent CN113883033A discloses a logic control method for tripping an electric feedwater pump for a CPR1000 nuclear power plant unit. The method includes: first, real-time monitoring of the nuclear power unit's electrical power signal to obtain the unit's total electrical power; real-time monitoring of the operating status of the electric main feedwater pump to obtain operating status information of the electric main feedwater pump; second, based on the unit's total electrical power and the operating status information of the electric main feedwater pump, determining whether the conditions for starting the standby pump are met; if so, controlling the standby pump to start; if not, maintaining the standby pump in a hot standby state. This patent, through real-time monitoring and determination of the nuclear power unit's total electrical power and the operating status information of the electric main feedwater pump, activates the standby pump according to the set conditions, ensuring that the secondary circuit water supply is not affected.

[0005] The starting conditions of each pump in the above two patents are fixed, and there is no special function of selecting the starting sequence, and it is impossible to achieve balanced use of the pumps. Summary of the Invention

[0006] Based on the above technical problems, the present invention proposes a control system and method for the startup sequence of waste liquid discharge pumps in a nuclear power plant to achieve balanced use of the pumps.

[0007] To achieve the above-mentioned object, the first aspect of the present invention provides a control system for the start-up sequence of waste liquid discharge pumps in a nuclear power plant, comprising a liquid level measuring device, an electronic control device and three waste liquid discharge pumps.

[0008] The liquid level measuring device is used to detect the liquid level height of the wastewater in the wastewater pit;

[0009] The electronic control device includes three logic control modules, each of which is connected to the liquid level measuring device and is used to output control instructions according to the liquid level height;

[0010] The three waste liquid discharge pumps are respectively connected to their corresponding logic control modules, and the waste liquid discharge pumps are used to perform corresponding operations according to the control instructions.

[0011] Furthermore, the logic control module includes an active / standby selection unit, a bistable trigger, two NOT gates, three AND gates and an OR gate.

[0012] The active terminal and the standby terminal of the active / standby selection unit are respectively connected to the first input terminal and the second input terminal of the bistable trigger, and the output terminal of the bistable trigger is used to output the status signal of the first waste liquid discharge pump;

[0013] A first AND gate is connected to the output end of the bistable trigger, and is used to receive the state signal of the first waste liquid discharge pump and the first liquid level signal, and perform an AND operation on the above signals;

[0014] a second AND gate connected to the output end of the bistable trigger via a first NOT gate, for receiving the NOT-operated state signal of the first waste liquid discharge pump, the second liquid level signal, and the state signal of the third waste liquid discharge pump, and performing an AND operation on the above signals;

[0015] A third AND gate is connected to the output end of the bistable trigger through a second NOT gate, and is used to receive the NOT-operated state signal of the first waste liquid discharge pump, the third liquid level signal, and the state signal of the second waste liquid discharge pump, and perform an AND operation on the above signals;

[0016] The OR gate is connected to the first AND gate, the second AND gate, and the third AND gate respectively, and is used to receive the first signal output by the first AND gate, the second signal output by the second AND gate, and the third signal output by the third AND gate, and perform an OR operation on the above signals, and then output a control instruction for the first waste liquid discharge pump.

[0017] Furthermore, the waste liquid discharge pump includes an automatic start gear, and the control instruction is output to the automatic start gear.

[0018] Furthermore, the waste liquid discharge pump also includes an automatic stop gear, and the logic control module also includes a delay relay.

[0019] When the received liquid level height signal is the fourth liquid level signal, the delay relay delays the fourth liquid level signal and outputs the delayed fourth liquid level signal to the automatic stop gear of the waste liquid discharge pump.

[0020] Furthermore, the waste liquid discharge pump also includes a protection stop gear.

[0021] The logic control module outputs the received protection trip signal to the protection stop gear.

[0022] Furthermore, the bistable trigger is an RS trigger.

[0023] Furthermore, the logic control module further includes an in-service status indicating unit for indicating that the waste liquid discharge pump is in an in-service state.

[0024] Furthermore, the system includes:

[0025] When the first waste liquid discharge pump is in service, the second waste liquid discharge pump and the third waste liquid discharge pump are in standby mode, and the starting sequence is the first waste liquid discharge pump - the second waste liquid discharge pump - the third waste liquid discharge pump;

[0026] When the second waste liquid discharge pump is in service, the first waste liquid discharge pump and the third waste liquid discharge pump are in standby mode, and the starting sequence is the second waste liquid discharge pump - the third waste liquid discharge pump - the first waste liquid discharge pump;

[0027] When the third waste liquid discharge pump is in service, the first waste liquid discharge pump and the second waste liquid discharge pump are in standby, and the starting sequence is the third waste liquid discharge pump - the first waste liquid discharge pump - the second waste liquid discharge pump.

[0028] Furthermore, the waste liquid discharge pump includes a seawater drainage pump.

[0029] To achieve the above-mentioned object, the second aspect of the present invention further provides a method for controlling the startup sequence of waste liquid discharge pumps in a nuclear power plant. The method can be applied to the above-mentioned waste liquid discharge pump startup sequence control system, and the method comprises:

[0030] Receive the detected liquid level height of wastewater in the wastewater pit;

[0031] Output a control instruction according to the liquid level height;

[0032] The waste liquid discharge pump is controlled to perform corresponding operations according to the control instructions.

[0033] Based on the above technical solution, the control system and method for the startup sequence of the waste liquid discharge pumps of a nuclear power plant have at least the following beneficial effects:

[0034] The present invention sets a pump to the in-service state through the in-service state indication unit of the logic control module, thereby determining the first pump to be started, and allocating the starting conditions of each pump according to the sequence. Through this method, different starting sequences and corresponding starting conditions of multiple waste liquid discharge pumps can be obtained, solving the problem of uneven utilization of pumps without increasing any investment, which is conducive to extending the service life of the equipment and has practical economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The accompanying drawings, which constitute part of the present invention, are intended to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are intended to explain the present invention and do not constitute an undue limitation of the present invention. In the accompanying drawings:

[0036] Figure 1 A schematic diagram of a control system for a start-up sequence of a waste liquid discharge pump in a nuclear power plant according to an embodiment of the present invention;

[0037] Figure 2 This is a schematic diagram of a logic control module corresponding to the first waste liquid discharge pump A in a specific embodiment of the present invention;

[0038] Figure 3 This is a schematic diagram of a logic control module corresponding to the second waste liquid discharge pump B in a specific embodiment of the present invention;

[0039] Figure 4 Schematic diagram of the logic control module corresponding to the third waste liquid discharge pump C in a specific embodiment of the present invention.

[0040] Figure 5 This is a flow chart of a method for controlling the startup sequence of a waste liquid discharge pump in a nuclear power plant according to one embodiment of the present invention. DETAILED DESCRIPTION

[0041] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments of the present invention can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0042] The present invention is further described in detail below with reference to specific examples. These examples should not be construed as limiting the scope of protection claimed in the present invention.

[0043] Example

[0044] In response to the problem of uneven use of waste liquid discharge pumps in the prior art, the present invention proposes a control system and method for the start-up sequence of nuclear power plant waste liquid discharge pumps, which achieves balanced use of the pumps by adjusting the start-up sequence of the pumps.

[0045] To achieve the above objectives, the present invention, in a first aspect, provides a control system for the startup sequence of waste liquid discharge pumps in a nuclear power plant.

[0046] Figure 1 FIG. 1 shows a schematic diagram of a control system for a start-up sequence of a nuclear power plant waste liquid discharge pump according to an embodiment of the present invention. Figure 1 As shown, the control system includes a liquid level measuring device 100, an electronic control device 200 and three waste liquid discharge pumps 300.

[0047] The liquid level measuring device 100 is used to detect the liquid level of wastewater in the wastewater pit. Specifically, the liquid level measuring device 100 can be a liquid level meter or a liquid level switch.

[0048] The electronic control device 200 may be a distributed control system (DCS) or other control devices. Specifically, in this embodiment, the electronic control device 200 includes three logic control modules 210, each of which is connected to the liquid level measuring device 100 and is used to output control instructions based on the liquid level.

[0049] In a specific embodiment of the present invention, Figure 2 As shown, the logic control module 210 includes an active / standby selection unit 211 , a bistable flip-flop 212 , two NOT gates 213 , three AND gates 214 and an OR gate 215 .

[0050] The active terminal and the standby terminal of the active / standby selection unit 211 are respectively connected to the first input terminal and the second input terminal of the bistable trigger 212 , and the output terminal of the bistable trigger 212 is used to output the status signal of the first waste liquid discharge pump.

[0051] In this specific embodiment, the three waste liquid discharge pumps are named A, B, and C, where A is the first waste liquid discharge pump, B is the second waste liquid discharge pump, and C is the third waste liquid discharge pump. The status signals of the three waste liquid discharge pumps are output via the bistable trigger 212, which are specifically divided into two states: in service and standby.

[0052] Specifically, in this embodiment, the bistable trigger 212 is an RS trigger.

[0053] While obtaining the status signals of the three waste liquid discharge pumps, it is also necessary to obtain the liquid level signal output by the liquid level measurement device. Finally, the control system combines the status signal and the liquid level signal to control the starting sequence of the waste liquid discharge pumps.

[0054] Specifically, the waste liquid pit is set with four liquid level values ​​of high 1, high 2, high 3, and low, which correspond to the first liquid level signal, the second liquid level signal, the third liquid level signal, and the fourth liquid level signal, respectively. When the output of the liquid level measuring device 100 is the first liquid level signal, the second liquid level signal, the third liquid level signal, or the fourth liquid level signal, the control system will combine the status signals of the three waste liquid discharge pumps ABC to control the start-up sequence of the waste liquid discharge pumps.

[0055] The following will focus on the first waste liquid discharge pump A and introduce its corresponding logic control module 210.

[0056] like Figure 2 As shown, the first AND gate 2141 is connected to the output end of the bistable trigger 212, and is used to receive the state signal of the first waste liquid discharge pump A and the first liquid level signal, and perform an AND operation on the above signals.

[0057] The second AND gate 2142 is connected to the output end of the bistable trigger 212 through the first NOT gate 2131, and is used to receive the status signal of the first waste liquid discharge pump A, the second liquid level signal and the status signal of the third waste liquid discharge pump C after the NOT operation, and perform an AND operation on the above signals.

[0058] The third AND gate 2143 is connected to the output end of the bistable trigger 212 through the second NOT gate 2132, and is used to receive the status signal of the first waste liquid discharge pump A, the third liquid level signal and the status signal of the second waste liquid discharge pump B after the NOT operation, and perform an AND operation on the above signals.

[0059] The corresponding AND operation output result can be obtained through the above process. In this embodiment, the first AND gate 2141, the second AND gate 2142, and the third AND gate 2143 are connected respectively through the OR gate 215, which is used to receive the first signal output by the first AND gate, the second signal output by the second AND gate, and the third signal output by the third AND gate, and perform an OR operation on the above signals, and then output a control instruction for the first waste liquid discharge pump A.

[0060] The three waste liquid discharge pumps A, B, and C are connected to their respective corresponding logic control modules and perform corresponding operations according to the control instructions. It should be understood that the control logic of the waste liquid discharge pumps B and C is the same as that of A, so they will not be repeated. Figure 3 This is a schematic diagram of the logic control module corresponding to the second waste liquid discharge pump B. Figure 4 This is a schematic diagram of the logic control module corresponding to the third waste liquid discharge pump C. Figure 3 and Figure 4 The meaning of each module shown in Figure 2 same.

[0061] In this specific embodiment, the waste liquid discharge pump includes an automatic start gear, and the system control instruction will be output to the automatic start gear to automatically start the corresponding waste liquid discharge pump.

[0062] Specifically, the waste liquid discharge pump further includes an automatic stop gear, and the logic control module 210 further includes a time delay relay 216 .

[0063] When the received liquid level height signal is the fourth liquid level signal, the delay relay 216 delays the fourth liquid level signal and outputs the delayed fourth liquid level signal to the automatic stop gear of the waste liquid discharge pump. In this embodiment, the delay time of the delay relay is set to 10 seconds.

[0064] In addition, the waste liquid discharge pump further includes a protection stop gear, and the logic control module 210 outputs the received protection trip signal to the protection stop gear.

[0065] In another specific embodiment of the present invention, the logic control module 210 further includes an in-service status indicating unit for indicating that the waste liquid discharge pump is in an in-service status.

[0066] In this specific embodiment, only one waste liquid discharge pump's status signal is allowed to be set to the active state. That is, if a waste liquid discharge pump is selected as the active state, the remaining waste liquid discharge pumps can only be set to the standby state. In this embodiment, the three waste liquid discharge pumps are named A, B, and C, where A is the first waste liquid discharge pump, B is the second waste liquid discharge pump, and C is the third waste liquid discharge pump. The specific control logic of the system is as follows:

[0067] If the in-service status indicating unit indicates that the first waste liquid discharge pump A is in service, and the second waste liquid discharge pump B and the third waste liquid discharge pump C are in standby status, in this case, the control system sets its startup sequence to first waste liquid discharge pump A-second waste liquid discharge pump B-third waste liquid discharge pump C.

[0068] After setting the start sequence, the control system will determine the corresponding pump start conditions based on the start sequence. In the above example, when the first waste liquid discharge pump A is selected and in service, the start condition for pump A is when the liquid level signal reaches the first liquid level signal, the start condition for pump B is when the liquid level signal reaches the second liquid level signal, and the start condition for pump C is when the liquid level signal reaches the third liquid level signal.

[0069] Similarly, if the in-service status indicating unit indicates that the second waste liquid discharge pump B is in service, and the first waste liquid discharge pump A and the third waste liquid discharge pump C are in standby status, in this case, the control system sets its startup sequence to the second waste liquid discharge pump B-the third waste liquid discharge pump C-the first waste liquid discharge pump A.

[0070] In this starting sequence, the starting condition for pump B is that it starts when the liquid level signal is the first liquid level signal, the starting condition for pump C is that it starts when the liquid level signal is the second liquid level signal, and the starting condition for pump A is that it starts when the liquid level signal is the third liquid level signal.

[0071] If the in-service status indicating unit indicates that the third waste liquid discharge pump C is in service, and the first waste liquid discharge pump A and the second waste liquid discharge pump B are in standby status, in this case, the control system sets its startup sequence to the third waste liquid discharge pump C-the first waste liquid discharge pump A-the second waste liquid discharge pump B.

[0072] In this starting sequence, the starting condition for pump C is that it starts when the liquid level signal is the first liquid level signal, the starting condition for pump A is that it starts when the liquid level signal is the second liquid level signal, and the starting condition for pump B is that it starts when the liquid level signal is the third liquid level signal.

[0073] Based on the above control logic, the three starting conditions of the waste liquid discharge pump under different starting sequences are combined as the automatic starting condition of a certain pump.

[0074] Furthermore, the waste liquid discharge pump may include a seawater drainage pump.

[0075] It should be understood that the present invention can set the status signal of the waste liquid discharge pump to the in-service or standby state by automatic rotation of the system or manual designation.

[0076] To achieve the above-mentioned object, the second aspect of the present invention further provides a method for controlling the startup sequence of waste liquid discharge pumps in a nuclear power plant, which can be applied to the above-mentioned control system.

[0077] like Figure 5 FIG. 1 shows a flow chart of a method for controlling the startup sequence of a waste liquid discharge pump of a nuclear power plant according to an embodiment of the present invention. Figure 5 As shown, the method includes the following steps:

[0078] S1, receiving the detected liquid level height of the wastewater in the wastewater pit.

[0079] S2, outputs control instructions according to the liquid level height.

[0080] S3, controlling the waste liquid discharge pump to perform corresponding operations according to the control instruction.

[0081] It should be understood that the control method of the startup sequence of the waste liquid discharge pumps of a nuclear power plant is consistent with the description of the corresponding control system embodiment of the startup sequence of the waste liquid discharge pumps of a nuclear power plant, so it will not be repeated in this embodiment.

[0082] In summary, from the above description, it can be seen that the above embodiments of the control system and method for the startup sequence of the waste liquid discharge pumps of a nuclear power plant achieve the following technical effects:

[0083] The present invention sets a pump to the in-service state through the in-service state indication unit of the logic control module, thereby determining the first pump to be started, and allocating the starting conditions of each pump according to the sequence. Through this method, different starting sequences and corresponding starting conditions of multiple waste liquid discharge pumps can be obtained, solving the problem of uneven utilization of pumps without increasing any investment, which is conducive to extending the service life of the equipment and has practical economic benefits.

[0084] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

[0085] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or device. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of other identical elements in the process, method, article, or device comprising the element.

[0086] The logic and / or steps represented in the flowchart or otherwise described herein may be considered, for example, as an ordered list of executable instructions for implementing logical functions, and may be embodied in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (such as a computer-based system, a system including a processor, or other system that can fetch and execute instructions from an instruction execution system, apparatus, or device).

[0087] It should be understood that various parts of the present invention can be implemented using hardware, software, firmware, or a combination thereof. In the above-described embodiments, multiple steps or methods can be implemented using software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented using hardware, as in another embodiment, any one of the following technologies known in the art or a combination thereof can be used: a discrete logic circuit having a logic gate circuit for implementing a logic function on a data signal, an application-specific integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0088] It should be noted that, in the description of this specification, the reference terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and the features of different embodiments or examples, unless they are contradictory.

Claims

1. A control system for the start-up sequence of waste liquid discharge pumps in a nuclear power plant, characterized in that: It includes a liquid level measuring device, an electronic control device and three waste liquid discharge pumps. The liquid level measuring device is used to detect the liquid level height of the wastewater in the wastewater pit; The electronic control device includes three logic control modules, each of which is connected to the liquid level measuring device and is used to output control instructions according to the liquid level height; The three waste liquid discharge pumps are respectively connected to their corresponding logic control modules, and the waste liquid discharge pumps are used to perform corresponding operations according to the control instructions; The status signal of the waste liquid discharge pump is set to the in-service or standby state by automatic rotation or manual designation; When the first waste liquid discharge pump is in service, the second waste liquid discharge pump and the third waste liquid discharge pump are in standby mode, and the starting sequence is the first waste liquid discharge pump - the second waste liquid discharge pump - the third waste liquid discharge pump; When the second waste liquid discharge pump is in service, the first waste liquid discharge pump and the third waste liquid discharge pump are in standby mode, and the starting sequence is the second waste liquid discharge pump - the third waste liquid discharge pump - the first waste liquid discharge pump; When the third waste liquid discharge pump is in service, the first waste liquid discharge pump and the second waste liquid discharge pump are in standby mode, and the starting sequence is the third waste liquid discharge pump - the first waste liquid discharge pump - the second waste liquid discharge pump; The logic control module includes an active / standby selection unit, a bistable trigger, two NOT gates, three AND gates and an OR gate. The active terminal and the standby terminal of the active / standby selection unit are respectively connected to the first input terminal and the second input terminal of the bistable trigger, and the output terminal of the bistable trigger is used to output the status signal of the first waste liquid discharge pump; A first AND gate is connected to the output end of the bistable trigger, and is used to receive the state signal of the first waste liquid discharge pump and the first liquid level signal, and perform an AND operation on the above signals; a second AND gate connected to the output end of the bistable trigger via a first NOT gate, for receiving the NOT-operated state signal of the first waste liquid discharge pump, the second liquid level signal, and the state signal of the third waste liquid discharge pump, and performing an AND operation on the above signals; A third AND gate is connected to the output end of the bistable trigger through a second NOT gate, and is used to receive the NOT-operated state signal of the first waste liquid discharge pump, the third liquid level signal, and the state signal of the second waste liquid discharge pump, and perform an AND operation on the above signals; The OR gate is connected to the first AND gate, the second AND gate, and the third AND gate respectively, and is used to receive the first signal output by the first AND gate, the second signal output by the second AND gate, and the third signal output by the third AND gate, and perform an OR operation on the above signals, and then output a control instruction for the first waste liquid discharge pump.

2. The system according to claim 1, wherein: The waste liquid discharge pump includes an automatic start gear, and the control instruction is output to the automatic start gear.

3. The system according to claim 1, wherein: The waste liquid discharge pump also includes an automatic stop gear, and the logic control module also includes a time delay relay. When the received liquid level height signal is the fourth liquid level signal, the delay relay delays the fourth liquid level signal and outputs the delayed fourth liquid level signal to the automatic stop gear of the waste liquid discharge pump.

4. The system according to claim 1, wherein: The waste liquid discharge pump also includes a protection stop gear, The logic control module outputs the received protection trip signal to the protection stop gear.

5. The system according to claim 1, wherein: The bistable trigger is an RS trigger.

6. The system according to claim 1, wherein: The logic control module further includes an in-service status indicating unit for indicating that the waste liquid discharge pump is in an in-service status.

7. The system according to claim 1, wherein: The waste liquid discharge pump includes a seawater drainage pump.

8. A method for controlling the startup sequence of waste liquid discharge pumps in a nuclear power plant, the method being applied to the control system according to any one of claims 1 to 7, characterized in that: include: Receive the detected liquid level height of wastewater in the wastewater pit; Outputting a control instruction according to the liquid level height; The waste liquid discharge pump is controlled to perform corresponding operations according to the control instructions.

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