A nuclear power plant auxiliary steam supply system and a heating control device thereof

Abstract

The application relates to a nuclear power plant auxiliary steam supply system and a heating control device thereof. The heating control device further comprises a valve arranged on an upstream pipeline connected with a steam inlet of a heater and electrically connected with a signal input end of a main control module. A pressure gauge is arranged on a downstream pipeline connected with a steam outlet of the heater and electrically connected with a signal input end of the main control module, and is used for detecting a pressure signal of steam in the pipeline. The main control module is further electrically connected with a control input end of the heater, and generates a starting control signal or a closing control signal according to a valve signal of the valve and a pressure signal of the pressure gauge, so that starting and closing of the heater are realized. The application cancels a target flowmeter with high failure rate, and the flow condition in the pipeline is represented by the related signals of the valve and the pressure gauge, so that the frequency of on-site maintenance can be effectively reduced, and the reliability of the SVA system is remarkably improved.

Description

Technical Field

[0001] This invention relates to the field of nuclear power plant heating control technology, and in particular to an auxiliary steam supply system for a nuclear power plant and its heating control device. Background Technology

[0002] The auxiliary steam supply system (SVA system) of a nuclear power plant provides quality steam to the turbine shaft sealing system to ensure shaft seal pressure. The main functions of turbine shaft seals include the following:

[0003] 1. Prevent steam leakage: Prevent high-pressure steam inside the turbine from leaking out axially, reduce steam loss, and improve unit efficiency.

[0004] 2. Prevent internal air leakage: Prevent outside air from entering the turbine, avoid disrupting the vacuum state of the condenser, and ensure the normal operation of the turbine.

[0005] 3. Protect the shaft system: Prevent the shaft from direct contact with the external environment, reduce shaft wear and corrosion, and extend the service life of the shaft.

[0006] 4. Maintaining unit thermal efficiency: Good shaft seals can reduce working fluid loss, which is of great significance for maintaining the thermal economy of the unit.

[0007] The SVA system heats the steam supplied to the turbine shaft sealing system via a heater (SVA201RS) to ensure steam quality. Typically, a target flow meter (SVA001LDS) is used to control the heater's start-up and shutdown. Its setpoint is 0.06 t / h; that is, when the flow rate measured by the target flow meter is less than 0.06 t / h, the heater will shut down. This design aims to prevent the heater from being damaged by dry burning when the upstream steam flow is low.

[0008] However, in practical applications, frequent failures of the target flow meter cause the SVA201RS heater to shut down frequently, preventing the heater from working properly and seriously affecting the normal function of the SVA system, as well as the safety and power generation efficiency of the steam turbine. Summary of the Invention

[0009] The technical problem to be solved by the present invention is to provide a nuclear power plant auxiliary steam supply system and its heating control device, in order to address the above-mentioned deficiencies.

[0010] The technical solution adopted by this invention to solve its technical problem is: a heating control device for an auxiliary steam supply system of a nuclear power plant, the heating control device including a heater, the steam outlet of the heater being connected to a turbine shaft sealing system via a downstream pipeline to provide heated steam to it, the heating control device further including:

[0011] The valve is located on the upstream pipe connected to the steam inlet of the heater and is electrically connected to the signal input terminal of the main control module;

[0012] A pressure gauge is installed on a downstream pipe connected to the steam outlet of the heater and electrically connected to the signal input terminal of the main control module to detect the pressure signal of the steam in the pipe.

[0013] The main control module is also electrically connected to the control input terminal of the heater, and generates a start control signal or a stop control signal based on the valve signal of the valve and the pressure signal of the pressure gauge, thereby realizing the start and stop of the heater.

[0014] Furthermore, in the heating control device for an auxiliary steam supply system of a nuclear power plant described in this invention, the main control module is used to determine whether the valve signal of the valve and the pressure signal of the pressure gauge meet preset conditions; if yes, it generates the start control signal to control the heater to start; if no, it generates the stop control signal to control the heater to stop.

[0015] Furthermore, in the heating control device for an auxiliary steam supply system of a nuclear power plant described in this invention, the preset conditions include:

[0016] First condition: The valve signal exceeds the preset valve opening value;

[0017] Second condition: The pressure signal exceeds a preset pressure value;

[0018] The main control module generates the start control signal when it determines that both of the above conditions are met simultaneously.

[0019] Furthermore, in the heating control device for an auxiliary steam supply system of a nuclear power plant described in this invention, the preset valve opening value is 5%; or

[0020] The preset pressure value is 0.1 MPa.

[0021] Furthermore, in the heating control device for an auxiliary steam supply system of a nuclear power plant described in this invention, the valve is a regulating valve, a shut-off valve, or a solenoid valve; or

[0022] The pressure gauge can be a mechanical pressure gauge or an electronic pressure gauge.

[0023] Furthermore, in the heating control device for the auxiliary steam supply system of a nuclear power plant described in this invention, the rated operating value of the pressure gauge is 0.65 MPa.

[0024] In addition, the present invention also provides a nuclear power plant auxiliary steam supply system, including the heating control device for a nuclear power plant auxiliary steam supply system as described above.

[0025] Furthermore, in the nuclear power plant auxiliary steam supply system described in this invention, the nuclear power plant auxiliary steam supply system also includes a human-machine interface connected to the main control module. The human-machine interface is used to receive and display valve signals and pressure signals transmitted by the main control module in real time or at regular intervals.

[0026] Furthermore, in the nuclear power plant auxiliary steam supply system described in this invention, the human-machine interface is also used to query the historical operating data of relevant instruments based on the first command input by the user.

[0027] Furthermore, in the nuclear power plant auxiliary steam supply system described in this invention, the human-machine interface is also used to receive a second instruction input by the user and transmit it to the main control module, and to display the life prediction results generated by the main control module instrument based on the instrument's historical operating data for life prediction of the corresponding instrument.

[0028] The nuclear power plant auxiliary steam supply system and its heating control device according to the present invention have the following beneficial effects: The present invention eliminates the target flow meter with a high failure rate, and uses valve and pressure gauge related signals to characterize the flow in the pipeline, which can effectively reduce the number of on-site maintenance and significantly improve the reliability of the SVA system. Attached Figure Description

[0029] The present invention will be further described below with reference to the accompanying drawings and embodiments. In the accompanying drawings:

[0030] Figure 1 This is a schematic diagram of a heating control device for a nuclear power plant auxiliary steam supply system according to an embodiment of the present invention;

[0031] Figure 2 This is a schematic diagram illustrating the working principle of a target flow meter in related technologies;

[0032] Figure 3 This is a schematic diagram of the heating control device of the auxiliary steam supply system of a nuclear power plant before related technological improvements;

[0033] Figure 4 This is a schematic diagram of the heating control device of the improved nuclear power plant auxiliary steam supply system according to the present invention. Detailed Implementation

[0034] To provide a clearer understanding of the technical features, objectives, and effects of the present invention, specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0035] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of the invention. However, those skilled in the art will understand that the invention can be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods are omitted so as not to obscure the description of the invention with unnecessary detail.

[0036] To facilitate understanding of the present invention, a more complete description will be provided below. The invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that the disclosure of the present invention will be more thorough and complete.

[0037] It should be noted that when an element is described as being "fixed to" another element, it can be directly on the other element, or one or more intermediate elements may exist between them. When an element is described as being "connected to" another element, it can be directly connected to the other element, or one or more intermediate elements may exist between them. When terms such as "vertical," "horizontal," "left," "right," "upper," "lower," "inner," "outer," and "bottom" are used to indicate orientation or positional relationships, this is based on the orientation or positional relationships shown in the accompanying drawings and is only for ease of description, not to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0038] It should be understood that although the terms first, second, third, etc., may be used in embodiments of the present invention to describe various information, this information should not be limited to these terms. These terms are only used to distinguish information of the same type from one another. No such actual relationship or order between these entities or operations is necessarily required or implied.

[0039] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0040] In one embodiment of the present invention, reference is made to... Figure 1 This embodiment of the heating control device for a nuclear power plant auxiliary steam supply system includes a heater. The steam outlet of the heater is connected to the turbine shaft sealing system via a downstream pipeline to provide heated steam. In other words, the heater is used to heat the steam supplied to the turbine shaft sealing system to ensure its steam quality, thereby ensuring the shaft sealing pressure of the turbine shaft sealing system. In this embodiment, the heating control device further includes:

[0041] The valve is located on the upstream pipe connected to the steam inlet of the heater and is electrically connected to the signal input terminal of the main control module. Alternatively, the valve in this embodiment may include, but is not limited to, a regulating valve, a shut-off valve, or a solenoid valve, etc.

[0042] A pressure gauge is installed on the downstream pipe connected to the steam outlet of the heater and electrically connected to the signal input terminal of the main control module. It is used to detect the pressure signal of the steam in the pipe. Alternatively, the pressure gauge in this embodiment can be a mechanical pressure gauge or an electronic pressure gauge. Of course, other electronic components capable of acquiring the pressure signal of the steam in the pipe can also be used.

[0043] In this embodiment, the working rated value of the pressure gauge can be selected as 0.65 MPa.

[0044] In one alternative embodiment, the valve, heater, and pressure gauge are located on the same process piping, with the valve upstream of the heater and the pressure gauge downstream. It is understood that the valve is installed on the piping between the steam inlet and the heater, and the pressure gauge is installed on the steam outlet piping between the heater and the heater.

[0045] The main control module is also electrically connected to the heater's control input terminal and generates start-up or stop-down control signals based on the valve signals and pressure gauge signals, thereby controlling the heater's start-up and stop-down. In other words, the valve opening signal and pressure gauge data are sent to the main control module for calculation, and the main control module outputs control signals based on the calculated results to control the heater's start-up and stop.

[0046] Optionally, the main control module determines whether the valve signal and the pressure gauge signal meet preset conditions. When the main control module determines that the valve signal and the pressure gauge signal meet the preset conditions, it generates a start control signal to control the heater to start. When the main control module determines that the valve signal and the pressure gauge signal do not meet the preset conditions, it generates a stop control signal to control the heater to stop.

[0047] In some embodiments, the preset conditions include: a first condition: the valve signal exceeds a preset valve opening value; and a second condition: the pressure signal exceeds a preset pressure value. The main control module generates a start control signal to allow the heater to start when both conditions are met simultaneously.

[0048] Alternatively, the preset valve opening value in this embodiment can be 5%, and the preset pressure value can be 0.1 MPa. Of course, depending on the actual needs of the specific nuclear power unit system, the preset valve opening value and preset pressure value can also be set to other required preset thresholds, such as a preset valve opening value of 8%, 10%, etc. When a gate valve is selected, the preset valve opening value is either fully open (100%) or fully closed (0%). No specific limitations are made here.

[0049] In related technologies, combined Figure 2 The working principle of the target flow meter is as follows: when the medium flows in the measuring tube, the pressure difference generated by its own kinetic energy passing through the flow obstruction element (target) exerts a force on the flow obstruction element, and the magnitude of the force is proportional to the square of the medium flow velocity.

[0050] The force F received by the flow obstruction element (target) is transmitted to the capacitive force sensor via a rigidly connected transmission element (measuring rod). The capacitive force sensor generates a voltage signal output, which, after pre-amplification, AD conversion, and computer processing, yields the corresponding instantaneous flow rate and cumulative total. Simultaneously, the amplified signal is compared with the corresponding voltage of the set value. If this signal is equal to or greater than (less than) the set value, the relay activates, outputting a switching signal. The operating state is changed by switching the relay on and off. The set value has an upper and lower limit, which can be preset at the factory according to user requirements or set on-site. Its adjustable range is 4% to 100% of full scale.

[0051] like Figure 3 The diagram shows the principle of the heating control device of the auxiliary steam supply system of the nuclear power plant before the improvement. When SVA001LDS≤0.06t / h, it indicates that there is no flow in the pipeline. In order to prevent the heater SVA201RS from burning dry, the heater SVA201RS needs to be shut down.

[0052] However, in practical applications, due to the instrument characteristics of the target flow meter SVA001LDS, and the fact that the set value of 0.06t / h required by the SVA system is too small for the target flow meter, its measured value cannot accurately reflect the steam flow in the pipeline. As a result, the heater often fails to work properly due to the failure of SVA001LDS, which seriously affects the normal function of the SVA system and the safety and power generation efficiency of the steam turbine.

[0053] like Figure 4 The diagram shown is a schematic representation of the heating control device for the improved auxiliary steam supply system of a nuclear power plant according to the present invention. The working principle of the heating control device of the present invention will be explained using a preset valve opening value of 5% and a preset pressure value of 0.1 MPa as an example.

[0054] After the improvement, SVA001LDS was eliminated. The presence or absence of flow in the pipeline is characterized by the opening signal of the upstream valve and the pressure signal entering the turbine shaft seal. When the following two conditions are met simultaneously, the heater SVA201RS is allowed to start: valve opening > 5%, indicating that the pipeline is open; pressure gauge pressure value > 0.1 MPa, indicating that the shaft seal inlet pressure of the shaft seal system is greater than 0.1 MPa, the current pipeline is in operation.

[0055] This embodiment eliminates the target flow meter, which has a high failure rate, and uses valve and pressure gauge signals to characterize the flow in the pipeline, which can effectively reduce the number of on-site maintenance and significantly improve the reliability of the SVA system.

[0056] In one embodiment of the present invention, the nuclear power plant auxiliary steam supply system of this embodiment includes a heating control device for the nuclear power plant auxiliary steam supply system as described in the above embodiments.

[0057] In one embodiment, the heating control device includes a heater, the steam outlet of which is connected to the turbine shaft sealing system via a downstream pipeline to provide heated steam to the system. That is, the heater is used to heat the steam supplied to the turbine shaft sealing system to ensure its steam quality, thereby ensuring the shaft sealing pressure of the turbine shaft sealing system. In this embodiment, the heating control device further includes:

[0058] The valve is located on the upstream pipe connected to the steam inlet of the heater and is electrically connected to the signal input terminal of the main control module. Alternatively, the valve in this embodiment may include, but is not limited to, a regulating valve, a shut-off valve, or a solenoid valve, etc.

[0059] A pressure gauge is installed on the downstream pipe connected to the steam outlet of the heater and electrically connected to the signal input terminal of the main control module. It is used to detect the pressure signal of the steam in the pipe. Alternatively, the pressure gauge in this embodiment can be a mechanical pressure gauge or an electronic pressure gauge. Of course, other electronic components capable of acquiring the pressure signal of the steam in the pipe can also be used.

[0060] In this embodiment, the working rated value of the pressure gauge can be selected as 0.65 MPa.

[0061] In one alternative embodiment, the valve, heater, and pressure gauge are located on the same process piping, with the valve upstream of the heater and the pressure gauge downstream. It is understood that the valve is installed on the piping between the steam inlet and the heater, and the pressure gauge is installed on the steam outlet piping between the heater and the heater.

[0062] The main control module is also electrically connected to the heater's control input terminal and generates start-up or stop-down control signals based on the valve signals and pressure gauge signals, thereby controlling the heater's start-up and stop-down. In other words, the valve opening signal and pressure gauge data are sent to the main control module for calculation, and the main control module outputs control signals based on the calculated results to control the heater's start-up and stop.

[0063] Optionally, the main control module determines whether the valve signal and the pressure gauge signal meet preset conditions. When the main control module determines that the valve signal and the pressure gauge signal meet the preset conditions, it generates a start control signal to control the heater to start. When the main control module determines that the valve signal and the pressure gauge signal do not meet the preset conditions, it generates a stop control signal to control the heater to stop.

[0064] In some embodiments, the preset conditions include: a first condition: the valve signal exceeds a preset valve opening value; and a second condition: the pressure signal exceeds a preset pressure value. The main control module generates a start control signal to allow the heater to start when both conditions are met simultaneously.

[0065] Alternatively, the preset valve opening value in this embodiment can be 5%, and the preset pressure value can be 0.1 MPa. Of course, depending on the actual needs of the specific nuclear power unit system, the preset valve opening value and preset pressure value can also be set to other required preset thresholds, such as a preset valve opening value of 8%, 10%, etc. When a gate valve is selected, the preset valve opening value is either fully open (100%) or fully closed (0%). No specific limitations are made here.

[0066] Alternatively, the nuclear power plant's auxiliary steam supply system may also include a human-machine interface connected to the main control module. The human-machine interface is used to receive and display valve signals and pressure signals transmitted by the main control module in real time or at regular intervals.

[0067] In some embodiments, the human-computer interaction interface is also used to query historical operating data of relevant instruments based on a first instruction input by the user.

[0068] In some embodiments, the human-machine interface is also used to receive a second instruction input by the user and transmit it to the main control module, and to display the life prediction result generated by the main control module instrument based on the instrument's historical operating data to predict the life of the corresponding instrument.

[0069] In some embodiments, the auxiliary steam supply system of a nuclear power plant may also be equipped with an alarm mechanism to monitor the actual operating signals of valves or pressure gauges in real time and to issue an alarm when the rated operating signal is exceeded.

[0070] This embodiment eliminates the target flow meter, which has a high failure rate, and uses valve and pressure gauge signals to characterize the flow in the pipeline, which can effectively reduce the number of on-site maintenance and significantly improve the reliability of the SVA system.

[0071] The main control module of this invention provides computing and control capabilities to support the operation of the entire heating control device. It should be understood that, in the embodiments of this application, the main control module may be a microcontroller unit (MCU), a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or any conventional processor.

[0072] Those skilled in the art will further recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of both. To clearly illustrate the interchangeability of hardware and software, the components and steps of the various examples have been generally described in terms of functionality in the foregoing description. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementations should not be considered beyond the scope of this invention.

[0073] The steps of the methods or algorithms described in conjunction with the embodiments disclosed herein can be implemented directly by hardware, a software module executed by a processor, or a combination of both. The software module can be located in random access memory (RAM), main memory, read-only memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, hard disk, removable disk, CD-ROM, or any other form of storage medium known in the art.

[0074] It is understood that the above embodiments only illustrate preferred embodiments of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can freely combine the above technical features without departing from the concept of the present invention, and can also make several modifications and improvements, all of which fall within the protection scope of the present invention. Therefore, all equivalent transformations and modifications made with respect to the scope of the claims of the present invention should fall within the scope of the claims of the present invention.

Claims

1. A heating control device for an auxiliary steam supply system in a nuclear power plant, characterized in that, The heating control device includes a heater, the steam outlet of which is connected to the turbine shaft sealing system via a downstream pipeline to provide heated steam to it. The heating control device also includes: The valve is located on the upstream pipe connected to the steam inlet of the heater and is electrically connected to the signal input terminal of the main control module; A pressure gauge is installed on a downstream pipe connected to the steam outlet of the heater and electrically connected to the signal input terminal of the main control module to detect the pressure signal of the steam in the pipe. The main control module is also electrically connected to the control input terminal of the heater, and generates a start control signal or a stop control signal according to the valve signal of the valve and the pressure signal of the pressure gauge, thereby realizing the start and stop of the heater; The main control module is used to determine whether the valve signal of the valve and the pressure signal of the pressure gauge meet preset conditions; if yes, it generates the start control signal to control the heater to start; if no, it generates the stop control signal to control the heater to stop. The preset conditions include: First condition: The valve signal exceeds the preset valve opening value; Second condition: The pressure signal exceeds a preset pressure value; The main control module generates the start control signal when it determines that both of the above conditions are met simultaneously.

2. The heating control device for an auxiliary steam supply system of a nuclear power plant according to claim 1, characterized in that, The preset valve opening value is 5%; or The preset pressure value is 0.1 MPa.

3. The heating control device for an auxiliary steam supply system in a nuclear power plant according to claim 1, characterized in that, The valve is a regulating valve, a shut-off valve, or a solenoid valve; or The pressure gauge can be a mechanical pressure gauge or an electronic pressure gauge.

4. The heating control device for an auxiliary steam supply system in a nuclear power plant according to claim 1, characterized in that, The pressure gauge has a rated operating pressure of 0.65 MPa.

5. A nuclear power plant auxiliary steam supply system, characterized in that, Includes a heating control device for an auxiliary steam supply system of a nuclear power plant as described in any one of claims 1 to 4.

6. The nuclear power plant auxiliary steam supply system according to claim 5, characterized in that, The nuclear power plant auxiliary steam supply system also includes a human-machine interface connected to the main control module. The human-machine interface is used to receive and display valve signals and pressure signals transmitted by the main control module in real time or at regular intervals.

7. The nuclear power plant auxiliary steam supply system according to claim 6, characterized in that, The human-computer interaction interface is also used to query the historical operating data of relevant instruments based on the first command input by the user.

8. The nuclear power plant auxiliary steam supply system according to claim 6, characterized in that, The human-machine interface is also used to receive a second instruction input by the user and transmit it to the main control module, and to display the life prediction result generated by the main control module based on the historical operating data of the instrument to predict the life of the corresponding instrument.

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