Overpressure protection system for nuclear power plant and nuclear power plant

Abstract

The present invention provides an overpressure protection system of a nuclear power plant and a nuclear power plant. The overpressure protection system is arranged on the main steam pipeline of a steam generator, and includes: a first discharge pipeline, a safety valve is arranged on the first discharge pipeline, and the safety valve is a passive safety valve; a second discharge pipeline, a discharge valve is arranged on the second discharge pipeline, and the discharge valve is connected to a controller, and the controller is also electrically connected to a sensor for detecting the pressure in the main steam pipeline; a third discharge pipeline, a first isolation valve is arranged on the third discharge pipeline, and the first isolation valve is communicatively connected to a sensor for detecting radiation in the main steam pipeline, and one end of the third discharge pipeline away from the main steam pipeline is connected to a waste liquid treatment system. The embodiment of the present invention can prevent radioactive substances from leaking into the external environment when radioactive substances leak, reduce the possibility of causing environmental pollution, and improve the safety factor of the nuclear power plant.

Description

Technical Field

[0001] The present invention relates to the field of nuclear power technology, and in particular to an overpressure protection system of a nuclear power plant and a nuclear power plant. Background Art

[0002] The power generation principle of existing nuclear power plants is to use steam to drive the steam turbine to complete the power generation operation. High-pressure steam is usually transported from the steam generator to the steam turbine through the main steam pipeline.

[0003] Since the steam pressure in the main steam pipeline is particularly high, usually above 7 MPa, if a fault occurs, the pressure may further increase and may bring certain dangers, so it is necessary to provide overpressure protection for the main steam pipeline. However, the existing overpressure protection system has a single function and can only discharge high-pressure steam into the nature to reduce the pressure in the main steam pipeline. If the fault is caused by a rupture in the steam generator heat transfer tube, it may cause radioactive substances to be released into the atmosphere when overpressure protection is executed, causing environmental pollution. Summary of the invention

[0004] The embodiment of the present invention provides an overpressure protection system of a nuclear power plant and a nuclear power plant, so as to solve the problem that the overpressure protection system of the existing nuclear power plant may cause the release of radioactive gas into the environment.

[0005] In a first aspect, an embodiment of the present invention provides an overpressure protection system for a nuclear power plant, which is arranged in a main steam pipeline of a steam generator, and includes:

[0006] a first discharge pipeline connected to the main steam pipeline, wherein a safety valve is provided on the first discharge pipeline, and the safety valve is a passive safety valve;

[0007] A second discharge pipeline connected to the main steam pipeline, wherein a discharge valve is provided on the second discharge pipeline, the discharge valve is connected to a controller, and the controller is also electrically connected to a sensor for detecting the pressure in the main steam pipeline;

[0008] A third discharge pipeline is connected to the main steam pipeline, and a first isolation valve is arranged on the third discharge pipeline. The first isolation valve is communicatively connected to a sensor for detecting radiation in the main steam pipeline. One end of the third discharge pipeline away from the main steam pipeline is connected to a waste liquid treatment system.

[0009] Optionally, the safety valve is a passive safety valve whose opening threshold is greater than the maximum pressure value of the discharge valve.

[0010] Optionally, a second isolation valve is further provided on the second discharge pipeline, and the second isolation valve is arranged on a side of the discharge valve close to the main steam pipeline.

[0011] Optionally, a muffler is provided at one end of the second discharge line away from the main steam pipe.

[0012] Optionally, the third discharge pipeline is further provided with a cooling component, and is located on a side of the first isolation valve away from the main steam pipeline.

[0013] Optionally, the cooling component is a cooling water pool.

[0014] Optionally, the number of the second isolation valves is at least two, and the at least two second isolation valves are connected in series.

[0015] Optionally, the first discharge pipeline, the second discharge pipeline and the third discharge pipeline are all directly connected to the main steam pipeline.

[0016] Optionally, two or three of the first discharge pipeline, the second discharge pipeline and the third discharge pipeline are connected to the main steam pipeline through the same branch pipeline.

[0017] In a second aspect, an embodiment of the present invention further provides a nuclear power plant, comprising the overpressure protection system of the nuclear power plant as described in any one of the above items.

[0018] The embodiment of the present invention cooperates with the first discharge pipeline, the second discharge pipeline and the third discharge pipeline. Under normal circumstances, the pressure in the main steam pipeline is regulated by the second discharge pipeline. When the pressure is too high, the passive safety valve on the first discharge pipeline can be started and steam discharge can be achieved to avoid excessive pressure in the main steam pipeline. If a radioactive substance leakage accident occurs, the radioactive steam is discharged to the waste liquid treatment system by opening the third discharge pipeline, which can not only achieve overpressure protection when the pressure in the main steam pipeline is too high, but also prevent the radioactive substance from leaking into the external environment when the radioactive substance leaks, thereby reducing the possibility of causing environmental pollution and improving the safety factor of the nuclear power plant. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments of the present invention will be briefly introduced below. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative labor.

[0020] Figure 1 is a schematic structural diagram of an overpressure protection system of a nuclear power plant in one embodiment of the present invention;

[0021] Figure 2 It is a structural schematic diagram of an overpressure protection system of a nuclear power plant in one embodiment of the present invention. DETAILED DESCRIPTION

[0022] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0023] An embodiment of the present invention provides an overpressure protection system for a nuclear power plant, which is arranged in a main steam pipe 200 of a steam generator 100 .

[0024] In one embodiment, Figure 1 As shown, the overpressure protection system of the nuclear power plant includes a first discharge pipeline 10, a second discharge pipeline 20 and a third discharge pipeline 30, and these three discharge pipelines are all connected to the main steam pipeline 200 of the steam generator 100 to discharge the steam in the main steam pipeline 200.

[0025] A safety valve 11 is provided on the first discharge pipeline 10. The safety valve 11 is a passive safety valve. A passive safety valve refers to a valve that does not rely on external power but automatically opens and closes according to the parameters of the main steam pipeline. Specifically, for example, it can be a spring-loaded passive safety valve, etc. The structure of the passive safety valve itself can refer to the relevant technology and is not further limited or described here.

[0026] The first discharge pipeline 10 is mainly used to release steam when the pressure in the main steam pipe 200 is too high. During implementation, a passive safety valve with a corresponding opening threshold can be selected according to safety conditions. For example, under normal circumstances, the pressure in the main steam pipe 200 is around 7MPa. Under special circumstances, it may reach 7.5MPa, but the pressure in the main steam pipe 200 cannot exceed 8MPa, so the opening pressure of the passive safety valve is set to 8MPa.

[0027] Obviously, during implementation, the opening threshold of the passive safety valve can be set and selected according to the situation, and is not further limited or described here.

[0028] The second discharge pipeline 20 is provided with a discharge valve 21 , which is connected to a controller. The controller is also electrically connected to a sensor for detecting the pressure in the main steam pipeline 200 .

[0029] The second discharge pipeline 20 is used to adjust the steam discharge according to the pressure in the main steam pipe 200. The discharge valve 21, the controller and the sensor can be directly electrically connected. In addition, the discharge valve 21, the controller and the sensor can also be indirectly electrically connected. For example, the controller can obtain the pressure data in the main steam pipe 200 detected by the sensor through the safety monitoring system of the nuclear power plant.

[0030] The higher the pressure in the main steam pipeline 200 is, the greater the opening degree of the discharge valve 21 is controlled to be, thereby maintaining the pressure in the main steam pipeline 200 within a relatively safe range.

[0031] The controller mentioned above may be an existing controller such as a single chip microcomputer, a microcontroller, a computer, etc. The sensor may also refer to the sensor in the related art, and its structure is not further limited or described here.

[0032] It should be understood that the safety valve 11 is a passive safety valve whose opening threshold is greater than the maximum pressure value of the discharge valve 21 .

[0033] That is to say, under normal operating conditions, all discharge pipelines are in a closed state. When the pressure in the main steam pipe 200 is slightly higher than the normal operating condition, the pressure in the main steam pipe 200 is adjusted through the second discharge pipeline 20. When the pressure in the main steam pipe 200 is too high and the second discharge pipeline 20 cannot meet the adjustment requirements, the pressure in the main steam pipe 200 will reach the adjustment threshold of the first discharge pipeline 10. At this time, the first discharge pipeline 10 is in working state to discharge the steam in the main steam pipe 200.

[0034] The first discharge pipeline 10 and the second discharge pipeline 20 can discharge the steam directly into the atmosphere, or they can process it. For example, the steam can be discharged into the atmosphere after cooling. Since the first discharge pipeline 10 and the second discharge pipeline 20 are mainly for working conditions where no radioactive material leakage occurs, discharging the gas directly into the atmosphere will not produce other adverse effects.

[0035] The third discharge pipeline 30 is used to prevent the release of radioactivity into the environment when a radioactive material leaks. A first isolation valve 31 is provided on the third discharge pipeline 30. The first isolation valve 31 is communicatively connected to a sensor for detecting radiation in the main steam pipe 200. One end of the third discharge pipeline 30 away from the main steam pipe 200 is connected to a waste liquid treatment system 300.

[0036] When leakage of radioactive material is detected, the first isolation valve 31 on the third discharge pipeline 30 is controlled to open, so that the steam contaminated with radioactive material enters the waste liquid treatment system 300 for treatment, thereby preventing the steam contaminated with radioactive material from being directly discharged into the atmosphere.

[0037] The waste liquid treatment system 300 may utilize the existing waste liquid treatment system 300 in the nuclear power plant, or may separately set up the waste liquid treatment system 300 with reference to the existing radioactive liquid treatment device. The structure thereof is not further limited or described herein.

[0038] The embodiment of the present invention cooperates with the first discharge pipeline 10, the second discharge pipeline 20 and the third discharge pipeline 30. Under normal circumstances, the pressure in the main steam pipeline 200 is adjusted by the second discharge pipeline 20. When the pressure is too high, the non-active safety valve on the first discharge pipeline 10 can be started and steam can be discharged to avoid excessive pressure in the main steam pipeline 200. If a radioactive substance leakage accident occurs, the third discharge pipeline 30 is opened to discharge the radioactive steam to the waste liquid treatment system 300, which can not only achieve overpressure protection when the pressure in the main steam pipeline 200 is too high, but also prevent the radioactive substance from leaking into the external environment when the radioactive substance leaks, thereby reducing the possibility of causing environmental pollution and improving the safety factor of the nuclear power plant.

[0039] Furthermore, a second isolation valve 22 is also provided on the second discharge pipeline 20 . The second isolation valve 22 is provided on a side of the discharge valve 21 close to the main steam pipeline 200 .

[0040] The second isolation valve 22 can be a pneumatic valve or an electric valve. The purpose of setting the second isolation valve 22 is to further improve the control effect on the second discharge pipeline 20 and improve its safety factor. Only when the second isolation valve 22 is opened, the discharge valve 21 can play a control effect on the steam. When the discharge valve 21 fails, the second isolation valve 22 can be closed to prevent the impact that may be caused by the failure of the discharge valve 21 to work normally.

[0041] Furthermore, a muffler 23 is provided at one end of the second discharge pipeline 20 away from the main steam pipe 200. The muffler 23 is used to reduce the noise when high-pressure steam is discharged, thereby reducing possible noise pollution. Its structure can refer to the muffler in the relevant technology.

[0042] It should be understood that the safety performance of the nuclear power plant is relatively high, and the overpressure condition and the radioactive material leakage condition are both low-probability events. However, in order to further improve safety, in this embodiment, a cooling assembly 32 is further provided on the third discharge pipeline 30, and the cooling assembly 32 is located on the side of the first isolation valve 31 away from the main steam pipeline 200. The cooling assembly 32 can select an existing or improved cooling water pool 32 or cooling tower, etc., which is not further limited and described here.

[0043] The cooling component 32 can reduce the temperature of the discharged steam to meet the temperature requirements of the waste liquid treatment system 300, and at the same time can improve the steam discharge efficiency, thereby reducing the possibility of an overpressure state in the main steam pipeline 200, and avoiding the first discharge pipeline 10 or the second discharge pipeline 20 from operating when a radioactive material leakage accident occurs, resulting in the discharge of radioactive materials into the atmosphere.

[0044] Furthermore, the number of the first isolation valves 31 is at least two, and at least two first isolation valves 31 are connected in series, which helps to further improve the safety factor and the reliability of the system operation.

[0045] In an optional specific embodiment, Figure 1 As shown, the first discharge pipeline 10, the second discharge pipeline 20 and the third discharge pipeline 30 are directly connected to the main steam pipeline 200, which helps to control them separately, simplify the structural design, and avoid interference between different discharge pipelines.

[0046] In another optional embodiment, Figure 2 As shown, two or three of the first discharge line 10 , the second discharge line 20 and the third discharge line 30 are connected to the main steam pipeline 200 through the same branch line 40 .

[0047] It can be understood that two or three of the first discharge pipeline 10, the second discharge pipeline 20 and the third discharge pipeline 30 are connected to the main steam pipeline 200 through a common branch pipeline 40, rather than being directly connected to the main steam pipeline 200. In this way, it is helpful to reduce the number of holes drilled on the main steam pipeline 200, reduce the possible damage to the main steam pipeline 200, and improve the reliability of the system.

[0048] An embodiment of the present invention further provides a nuclear power plant, comprising any one of the above overpressure protection systems for the nuclear power plant.

[0049] Among them, other structures of the nuclear power plant can refer to relevant technologies and are not further limited and described here. Since this embodiment includes all the technical solutions of the above embodiments, it can at least achieve all the above technical effects and will not be repeated here.

[0050] The above are only specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art who is familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. An overpressure protection system for a nuclear power plant, arranged in the main steam pipeline of a steam generator, characterized in that: include: a first discharge pipeline connected to the main steam pipeline, wherein a safety valve is provided on the first discharge pipeline, and the safety valve is a passive safety valve; A second discharge pipeline connected to the main steam pipeline, wherein a discharge valve is provided on the second discharge pipeline, the discharge valve is connected to a controller, and the controller is also electrically connected to a sensor for detecting the pressure in the main steam pipeline; a third discharge pipeline connected to the main steam pipeline, wherein a first isolation valve is disposed on the third discharge pipeline, the first isolation valve is communicatively connected to a sensor for detecting radiation in the main steam pipeline, and an end of the third discharge pipeline away from the main steam pipeline is connected to a waste liquid treatment system; The number of the first isolation valves is at least two, and the at least two first isolation valves are connected in series; the third discharge pipeline is also provided with a cooling component, and is located on a side of the first isolation valve away from the main steam pipeline; The first discharge pipeline and the second discharge pipeline are used to be opened when no leakage of radioactive substances occurs, and the third discharge pipeline is used to be opened when leakage of radioactive substances occurs.

2. The overpressure protection system for a nuclear power plant according to claim 1, characterized in that: The safety valve is a passive safety valve whose opening threshold is greater than the maximum pressure value of the discharge valve.

3. The overpressure protection system for a nuclear power plant according to claim 1, characterized in that: The second discharge pipeline is also provided with a second isolation valve, and the second isolation valve is arranged on a side of the discharge valve close to the main steam pipeline.

4. The overpressure protection system for a nuclear power plant according to claim 1, characterized in that: A muffler is provided at one end of the second discharge line away from the main steam pipe.

5. The overpressure protection system for a nuclear power plant according to claim 1, characterized in that: The cooling component is a cooling water pool.

6. The overpressure protection system for a nuclear power plant according to any one of claims 1 to 5, characterized in that: The first discharge pipeline, the second discharge pipeline and the third discharge pipeline are all directly connected to the main steam pipeline.

7. The overpressure protection system for a nuclear power plant according to any one of claims 1 to 5, characterized in that: Two or three of the first discharge pipeline, the second discharge pipeline and the third discharge pipeline are connected to the main steam pipeline through the same branch pipeline.

8. A nuclear power plant, characterized in that: An overpressure protection system for a nuclear power plant comprising any one of claims 1 to 7.

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