A control system and method for automatic rotation of pit pumps in nuclear power plants

Abstract

The present invention discloses a control system and method for automatically rotating sump pumps in a nuclear power plant. The control system includes a liquid level measuring device, an electronic control device, and two sump pumps. The liquid level measuring device is used to detect the liquid level of non-radioactive wastewater in the sump. The electronic control device is connected to the liquid level measuring device and includes two bistable triggers. The electronic control device is used to output sump pump control instructions for the next operating cycle based on the liquid level and using the two bistable triggers. The two sump pumps are connected to the electronic control device and are used to perform corresponding operations according to the sump pump control instructions. The control system and method for automatically rotating sump pumps in a nuclear power plant of the present invention can, in the event that a single sump pump cannot lower the sump water level to a low level and two sump pumps are required to operate, still achieve an interchange of the sump pump startup sequence, achieve complete automatic rotation of the sump pumps, and better balance the operating time of the two sump pumps.

Description

Technical Field

[0001] The present invention relates to the technical field of nuclear power plant pit pump control, and in particular to a control system and method for automatic rotation of a nuclear power plant pit pump. Background Art

[0002] Non-radioactive wastewater from nuclear power plants is typically collected in pits, a large number of which are located throughout the plant. Level meters and pit pumps are installed within the pits to monitor the water level and discharge the wastewater. Each pit typically has two identical pit pumps. During automatic operation, the pit pump control logic is as follows: one pit pump starts when the liquid level is high, the other starts when the liquid level is high-high, and all pit pumps stop when the liquid level is low. To balance the operating time of the two pit pumps, if only one pit pump is started, the pit level can be lowered to the low level. In the next operating cycle, the starting order of the two pit pumps is swapped (the process of pit level changing from high to low is considered an operating cycle). If the high-high liquid level occurs during the current operating cycle, meaning both pit pumps are operating simultaneously, the starting order of the pit pumps is not swapped in the next operating cycle. However, this control method does not fully implement the rotation requirement. When two sump pumps operate together, the drainage volume increases, which can reduce the sump liquid level to a low level in a short time. If the operating order is not exchanged in the next cycle, the operating time of the second sump pump will be shorter than that of the first sump pump, which is not conducive to the balance of the sump pump operating time and does not meet the upstream professional control requirements.

[0003] CN105390172A discloses a nuclear power plant waste liquid discharge system. Its waste liquid input pipeline includes an input main pipe connected to the waste liquid discharge pipeline of the upstream system and input branches connected to the inlets of different waste liquid storage tanks. Each input branch is equipped with an inlet isolation valve. These inlet isolation valves are connected to the system control device and controlled by the system control device according to preset interlock control information to ensure that waste liquid from the upstream system can be automatically input into available waste liquid storage tanks and realize automatic switching of waste liquid storage tanks. This patent realizes automatic switching of waste liquid storage tanks through a logic control program.

[0004] CN112786225A discloses a pit pump system for a nuclear power plant, comprising a wastewater collection tank, a wastewater level meter positioned above the tank for detecting the wastewater level within the tank, a pumping device for pumping wastewater out of the tank, a pumping line connected to the tank, a drain line connected to an external wastewater treatment system, and a control device for controlling the activation of the pumping device based on the water level. This patent ensures that radioactive wastewater does not leak throughout the life of a nuclear power plant.

[0005] Both of the above patents cannot achieve balanced operation time of the pit pump and do not meet the control requirements of upstream professionals. Summary of the Invention

[0006] The object of the present invention is to solve one of the above-mentioned technical problems at least to a certain extent.

[0007] To this end, the first object of the present invention is to provide a control system for automatic rotation of pit pumps in a nuclear power plant, which can realize complete automatic rotation of the pit pumps and better balance the operating time of the two pit pumps.

[0008] The second object of the present invention is to provide a control method for automatic rotation of a pit pump in a nuclear power plant.

[0009] In order to achieve the above-mentioned purpose, the first embodiment of the present invention provides a control system for automatic rotation of pit pumps in a nuclear power plant, comprising a liquid level measuring device, an electronic control device and two pit pumps.

[0010] The liquid level measuring device is used to detect the liquid level height of the non-radioactive wastewater in the pit;

[0011] The electronic control device is connected to the liquid level measuring device, and includes two bistable triggers. The electronic control device is used to output a pit pump control instruction for the next operation cycle according to the liquid level and using the two bistable triggers;

[0012] The two pit pumps are connected to the electric control device, and the two pit pumps are used to perform corresponding operations according to the pit pump control instructions.

[0013] Optionally, the electronic control device includes two power-on delay relays, two NOT gates and four AND gates, and the two pit pumps are pump A and pump B respectively.

[0014] The first power-on delay relay is used to receive the pump A start instruction and perform signal delay on the pump A start instruction;

[0015] A first NOT gate is connected to the first power-on delay relay, and is used to perform a NOT operation on the A pump start instruction after the first power-on delay relay has delayed the instruction;

[0016] The second power-on delay relay is used to receive the B pump start instruction and perform signal delay on the B pump start instruction;

[0017] The second NOT gate is connected to the second power-on delay relay, and is used to perform a NOT operation on the B pump start instruction after the second power-on delay relay delays;

[0018] The first AND gate is connected to the first power-on delay relay and the second NOT gate respectively, and is used to receive the automatic state signal of pump B, the start instruction of pump B after the NOT operation, and the start instruction of pump A after the delay, and perform an AND operation on the above signals;

[0019] The second AND gate is connected to the second power-on delay relay and the first NOT gate respectively, and is used to receive the automatic state signal of pump A, the start instruction of pump A after the NOT operation, and the start instruction of pump B after the delay, and perform an AND operation on the above signals;

[0020] A first bistable trigger is connected to the first AND gate and the second AND gate respectively, and is used to receive a first signal output by the first AND gate and a second signal output by the second AND gate;

[0021] a third AND gate connected to the first bistable flip-flop, configured to receive a pump A shutdown instruction and a first output result of the first bistable flip-flop, and perform an AND operation on the pump A shutdown instruction and the first output result to generate a third output result;

[0022] a fourth AND gate connected to the first bistable flip-flop, configured to receive a pump B stop instruction and a second output result of the first bistable flip-flop, and perform an AND operation on the pump B stop instruction and the second output result to generate a fourth output result;

[0023] The second bistable trigger is connected to the third AND gate and the fourth AND gate respectively, and is used to receive the third output result and the fourth output result, and generate a pit pump control instruction for the next operation cycle.

[0024] Optionally, the signal delay time of the first power-on delay relay and the second power-on delay relay is 2 seconds.

[0025] Optionally, the A pump start instruction and the B pump start instruction are final start instructions generated by manual start or automatic start.

[0026] Optionally, the first AND gate and the second AND gate perform AND operations on signals synchronously.

[0027] Optionally, the pump A stop instruction and the pump B stop instruction are obtained by performing an OR operation on a low liquid level signal, a fault signal, and a manual signal.

[0028] Optionally, the pit pump control instruction for the next operation cycle includes a pump A selection signal and a pump B selection signal.

[0029] When the A pump selection signal is 1, the A pump is started first in the next operation cycle;

[0030] When the B pump selection signal is 1, the B pump is started first in the next operation cycle.

[0031] Optionally, the bistable trigger is an RS trigger.

[0032] Optionally, the electronic control device includes a control module and a power distribution module.

[0033] The control module is used to execute control logic;

[0034] The power distribution module is used to supply power to the control module and the pit pump.

[0035] The control system for automatic rotation of sump pumps in a nuclear power plant according to an embodiment of the present invention is such that, when a single sump pump is unable to lower the sump water level to a low liquid level and two sump pumps are required to operate, the sump pump start-up sequence can still be exchanged in this case, thereby achieving complete automatic rotation of the sump pumps and better balancing the operating time of the two sump pumps.

[0036] To achieve the above-mentioned object, a second embodiment of the present invention provides a method for controlling automatic rotation of a pit pump in a nuclear power plant, comprising:

[0037] Receive the detected level of non-radioactive wastewater in the pit;

[0038] According to the liquid level, two bistable triggers are used to output the pit pump control instruction for the next operation cycle;

[0039] The pit pump is controlled to perform corresponding operations according to the pit pump control instruction.

[0040] The control method for automatic rotation of sump pumps in a nuclear power plant according to an embodiment of the present invention is such that, when a single sump pump is unable to lower the sump water level to a low liquid level, two sump pumps are required to operate. In this case, the start-up sequence of the sump pumps can still be exchanged, thereby achieving complete automatic rotation of the sump pumps and better balancing the operating time of the two sump pumps. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] 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:

[0042] Figure 1 This is a schematic structural diagram of a control system for automatic rotation of a pit pump in a nuclear power plant according to an embodiment of the present invention;

[0043] Figure 2 is a control logic diagram of an electronic control device 200 according to an embodiment of the present invention;

[0044] Figure 3 It is a structural schematic diagram of a control system for automatic rotation of a pit pump in a nuclear power plant according to another embodiment of the present invention;

[0045] Figure 4 The present invention is a flowchart of a method for controlling automatic rotation of a pit pump in a nuclear power plant according to an embodiment of the present invention. DETAILED DESCRIPTION

[0046] 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.

[0047] 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.

[0048] The following describes a control system and method for automatic rotation of a nuclear power plant pit pump according to an embodiment of the present invention with reference to the accompanying drawings.

[0049] In response to the problems existing in the prior art in controlling pit pumps in nuclear power plants, the present invention provides a novel pit pump automatic rotation control system and method, which can achieve complete pit pump rotation and better balance the pit pump operating time.

[0050] Figure 1 The present invention is a schematic structural diagram of a control system for automatic rotation of a pit pump in a nuclear power plant according to an embodiment of the present invention.

[0051] like Figure 1 As shown, the control system for automatic rotation of sump pumps in a nuclear power plant includes a liquid level measuring device 100 , an electric control device 200 and two sump pumps 300 .

[0052] The liquid level measuring device 100 is used to detect the liquid level of the non-radioactive wastewater in the pit. The liquid level measuring device 100 can be a liquid level meter or a liquid level switch.

[0053] The electronic control device 200 is connected to the liquid level measuring device 100. It includes two bistable flip-flops 210. Based on the liquid level, the electronic control device 200 utilizes the two bistable flip-flops to output control instructions for the next sump pump operation cycle. The electronic control device 200 can be a control cabinet or a control box. The control logic for the sump pump is implemented in the electronic control device 200. The electronic control device 200 can be implemented using relays, a programmable logic controller (PLC), or a distributed control system (DCS).

[0054] The two pit pumps 300 are connected to the electric control device 200. The two pit pumps 300 are used to perform corresponding operations according to the pit pump control instructions.

[0055] In one embodiment of the present invention, Figure 2As shown, the electronic control device 200 is implemented using relays. When implemented using relays, two bistable flip-flops can memorize the operating process of the sump pump 300. Specifically, the electronic control device 200 includes two power-on delay relays 220, two NOT gates 230, and four AND gates 240. The two sump pumps are Pump A and Pump B, respectively.

[0056] Among them, there are a first bistable trigger 211 and a second bistable trigger 212 ; a first power-on delay relay 221 and a second power-on delay relay 222 ; a first NOT gate 231 and a second NOT gate 232 ; a first AND gate 241 , a second AND gate 242 , a third AND gate 243 and a fourth AND gate 244 .

[0057] The first power-on delay relay 221 is used to receive the Pump A start command and perform a signal delay on the command. The second power-on delay relay 222 is used to receive the Pump B start command and perform a signal delay on the command. The signal delays provided by the first and second power-on delay relays 221 and 222 are each 2 seconds. The Pump A and Pump B start commands are the final start commands generated by manual or automatic start.

[0058] The first NOT gate 231 is connected to the first power-on delay relay 221 and is used to perform a NOT operation on the A pump start instruction after the delay of the first power-on delay relay 221 .

[0059] The second NOT gate 232 is connected to the second power-on delay relay 222 and is used to perform a NOT operation on the B pump start instruction after the delay of the second power-on delay relay 222 .

[0060] The first AND gate 241 is connected to the first power-on delay relay 221 and the second NOT gate 232 respectively, and is used to receive the automatic status signal of pump B, the B pump start instruction after the NOT operation, and the A pump start instruction after the delay, and perform AND operation on the above signals.

[0061] A second AND gate 242 is connected to the second power-on delay relay 222 and the first NOT gate 231, respectively, and is configured to receive the automatic status signal of Pump A, the pump A start command after the NOT operation, and the pump B start command after the delay, and perform an AND operation on these signals. The AND operations on the signals by the first AND gate 241 and the second AND gate 242 are performed synchronously.

[0062] The first bistable trigger 211 is connected to the first AND gate 241 and the second AND gate 242 respectively, and is configured to receive the first signal output by the first AND gate 241 and the second signal output by the second AND gate 242 .

[0063] The third AND gate 243 is connected to the first bistable trigger 211 and is configured to receive the pump A shutdown instruction and the first output result of the first bistable trigger 211 and perform an AND operation on the pump A shutdown instruction and the first output result to generate a third output result.

[0064] Fourth AND gate 244 is connected to first flip-flop 211 and is configured to receive the pump B shutdown command and the second output of first flip-flop 211, and perform an AND operation on the pump B shutdown command and the second output to generate a fourth output. The pump A shutdown command and the pump B shutdown command are obtained by performing an OR operation on the low liquid level signal, the fault signal, and the manual signal.

[0065] The second bistable flip-flop 212 is connected to the third and fourth AND gates 243 and 244, respectively, and is configured to receive the third and fourth output results and generate a sump pump control instruction for the next operating cycle. The sump pump control instruction for the next operating cycle includes a pump A selection signal and a pump B selection signal. When the pump A selection signal is 1, pump A is activated first in the next operating cycle; when the pump B selection signal is 1, pump B is activated first in the next operating cycle.

[0066] It should be understood that both the first bistable trigger 211 and the second bistable trigger 212 are RS triggers.

[0067] In another embodiment, Figure 3 As shown, the electric control device 200 may include a control module 250 and a power distribution module 260 .

[0068] If the electronic control device 200 is implemented using a DCS, since DCS is a control system for the entire nuclear power plant, the power supply portion is generally separate from the control portion. Therefore, the electronic control device 200 can be divided into two parts: a control module 250 and a power distribution module 260. The control module 250 is used to execute the control logic, i.e., the control logic of the electronic control device 200 in the previous embodiment. The power distribution module 260 is used to power the control module 250 and the sump pump 300. The power distribution module 260 may include components such as circuit breakers, contactors, and thermal relays.

[0069] The electronic control device 200 receives the liquid level signal and the manual operation signal, and issues a pit pump start / stop command after logical operation. The pit pump start / stop command is sent to the power supply of the pit pump or the power supply part of the electronic control device 200 .

[0070] In addition, the electronic control device 200 may also include operating components such as a manual-automatic switch and a manual start-stop switch.

[0071] The execution logic of the control system for the automatic rotation of the pit pump in a nuclear power plant is as follows:

[0072] The operating status of the pit pump is memorized by setting up a two-stage bistable trigger. When Pump A is operating alone and Pump B is automatically operating, the first bistable trigger memorizes this operating status (the state in which Pump A is running and Pump B is stopped, that is, Pump A starts first) without triggering the pump stop command. However, this memorized status cannot be output immediately because the current operating cycle has not yet ended. Immediate output would disrupt the operating status. Therefore, the operating status needs to be saved until the end of the current operating cycle. That is, when the pit pump is stopped, the operating status is saved to the second bistable trigger. The function of the second bistable trigger is to save the operating status from the end of the current operating cycle to the beginning of the next operating cycle.

[0073] The control system for automatic rotation of sump pumps in a nuclear power plant according to an embodiment of the present invention is such that, when a single sump pump is unable to lower the sump water level to a low liquid level and two sump pumps are required to operate, the sump pump start-up sequence can still be exchanged in this case, thereby achieving complete automatic rotation of the sump pumps and better balancing the operating time of the two sump pumps.

[0074] In order to implement the above embodiment, the present invention also proposes a control method for automatic rotation of a pit pump in a nuclear power plant.

[0075] Figure 4 The present invention is a flowchart of a method for controlling automatic rotation of a pit pump in a nuclear power plant according to an embodiment of the present invention.

[0076] like Figure 4 As shown, the control method for automatic rotation of the pit pump in a nuclear power plant includes the following steps:

[0077] S1, receives the detected liquid level height of non-radioactive wastewater in the pit.

[0078] S2, based on the liquid level, uses two bistable triggers to output the pit pump control instruction for the next operation cycle.

[0079] S3, controlling the pit pump to perform corresponding operations according to the pit pump control instruction.

[0080] It should be understood that the control method for automatic rotation of the pit pump in a nuclear power plant is consistent with the description of the corresponding system embodiment, so it will not be repeated in this embodiment.

[0081] The control method for automatic rotation of sump pumps in a nuclear power plant according to an embodiment of the present invention is such that, when a single sump pump is unable to lower the sump water level to a low liquid level, two sump pumps are required to operate. In this case, the start-up sequence of the sump pumps can still be exchanged, thereby achieving complete automatic rotation of the sump pumps and better balancing the operating time of the two sump pumps.

[0082] 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.

[0083] The logic and / or steps represented in the flowcharts or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing the logical functions, and can be embodied in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (e.g., 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). For purposes of this specification, a "computer-readable medium" can be any device that can contain, store, communicate, propagate, or transport a program for use by, or in conjunction with, an instruction execution system, apparatus, or device. More specific examples (a non-exhaustive list) of computer-readable media include the following: an electrical connection with one or more wires (electronic devices), a portable computer disk cartridge (magnetic device), random access memory (RAM), read-only memory (ROM), erasable and programmable read-only memory (EPROM or flash memory), fiber optic devices, and a portable compact disc read-only memory (CDROM). Furthermore, the computer-readable medium may even be paper or other suitable medium on which the program is printed, since the program may be obtained electronically, for example, by optically scanning the paper or other medium and then editing, interpreting or otherwise processing it in a suitable manner if necessary, and then storing it in a computer memory.

[0084] 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.

[0085] 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 automatic rotation of pit pumps in nuclear power plants, characterized in that: It includes a liquid level measuring device, an electronic control device and two pit pumps. The liquid level measuring device is used to detect the liquid level height of the non-radioactive wastewater in the pit; The electronic control device is connected to the liquid level measuring device, and includes two bistable triggers. The electronic control device is used to output a pit pump control instruction for the next operation cycle according to the liquid level and using the two bistable triggers; The two pit pumps are connected to the electric control device, and the two pit pumps are used to perform corresponding operations according to the pit pump control instructions; The electric control device includes two power-on delay relays, two NOT gates and four AND gates. The two pit pumps are pump A and pump B. The first power-on delay relay is used to receive the pump A start instruction and perform signal delay on the pump A start instruction; A first NOT gate is connected to the first power-on delay relay, and is used to perform a NOT operation on the A pump start instruction after the first power-on delay relay has delayed the instruction; The second power-on delay relay is used to receive the B pump start instruction and perform signal delay on the B pump start instruction; The second NOT gate is connected to the second power-on delay relay, and is used to perform a NOT operation on the B pump start instruction after the second power-on delay relay delays; The first AND gate is connected to the first power-on delay relay and the second NOT gate respectively, and is used to receive the automatic state signal of pump B, the start instruction of pump B after the NOT operation, and the start instruction of pump A after the delay, and perform an AND operation on the above signals; The second AND gate is connected to the second power-on delay relay and the first NOT gate respectively, and is used to receive the automatic state signal of pump A, the start instruction of pump A after the NOT operation, and the start instruction of pump B after the delay, and perform an AND operation on the above signals; A first bistable trigger is connected to the first AND gate and the second AND gate respectively, and is used to receive a first signal output by the first AND gate and a second signal output by the second AND gate; a third AND gate connected to the first bistable flip-flop, configured to receive a pump A shutdown instruction and a first output result of the first bistable flip-flop, and perform an AND operation on the pump A shutdown instruction and the first output result to generate a third output result; a fourth AND gate connected to the first bistable flip-flop, configured to receive a pump B stop instruction and a second output result of the first bistable flip-flop, and perform an AND operation on the pump B stop instruction and the second output result to generate a fourth output result; The second bistable trigger is connected to the third AND gate and the fourth AND gate respectively, and is used to receive the third output result and the fourth output result, and generate a pit pump control instruction for the next operation cycle.

2. The system according to claim 1, wherein: The signal delay time of the first power-on delay relay and the second power-on delay relay is 2 seconds.

3. The system according to claim 1, wherein: The A pump start instruction and the B pump start instruction are final start instructions generated by manual start or automatic start.

4. The system according to claim 1, wherein: The first AND gate and the second AND gate perform AND operations on signals synchronously.

5. The system according to claim 1, wherein: The pump A stop instruction and the pump B stop instruction are obtained by performing an OR operation on a low liquid level signal, a fault signal, and a manual signal.

6. The system according to claim 1, wherein: The pit pump control instruction of the next operation cycle includes the A pump selection signal and the B pump selection signal. When the A pump selection signal is 1, the A pump is started first in the next operation cycle; When the B pump selection signal is 1, the B pump is started first in the next operation cycle.

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

8. The system according to claim 1, wherein: The electronic control device includes a control module and a power distribution module. The control module is used to execute control logic; The power distribution module is used to supply power to the control module and the pit pump.

9. A method for controlling the automatic rotation of a pit pump in a nuclear power plant, the method being applied to the control system according to any one of claims 1 to 8, characterized in that: include: Receive the detected level of non-radioactive wastewater in the pit; According to the liquid level, two bistable triggers are used to output the pit pump control instruction for the next operation cycle; The pit pump is controlled to perform corresponding operations according to the pit pump control instruction.

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