Pressurizing system for hydraulic pressure test of primary loop of nuclear power station and switching method

Abstract

The invention is applicable to the field of nuclear power reliability detection, and discloses a nuclear power station primary loop hydrostatic test boosting system and a switching method, and the system comprises a first charging pump, a boosting liquid supply unit, a recovery unit, a first minimum flow valve, a water filling pipeline and a control unit; the boosting liquid supply unit comprises a boosting pump and a first control valve; the recovery unit comprises a first flow meter and a volume control box; the first minimum flow valve comprises a water inlet, a first water outlet and a second water outlet; a first charging pump is started to supply liquid to a first loop, a first water outlet of a minimum flow valve is kept open, after the first loop is filled with liquid, the hydraulic pressure at the first water outlet reaches a specified value, a second water outlet is opened, the liquid flows into a second water path, and then a first flow meter detects the liquid flow and feeds a signal back to a control unit; and the control unit judges that the liquid is filled, the control unit starts the booster pump, and the booster pump starts to boost the pressure in the loop, so that the switching of the booster system is completed.

Description

Technical Field

[0001] The invention relates to the field of nuclear power reliability detection, and in particular to a primary circuit water pressure test boosting system and a switching method for a nuclear power plant. Background Art

[0002] Domestic nuclear reactor units are generally equipped with a primary circuit and a secondary circuit. The liquid in the primary circuit is in direct contact with the reactor and generally contains higher radiation. The secondary circuit is set in the evaporator to exchange heat with the liquid in the primary circuit through external pure water. The primary circuit water pressure test of a pressurized water reactor nuclear power plant is a necessary link in the construction process of a nuclear power plant. Before conducting a primary circuit water pressure test, a reasonable water pressure test plan must be formulated first. The water pressure test plan generally involves specific content in terms of test parameters, test procedures, test reports, etc. When formulating a water pressure test plan, factors such as system integrity, safety, and reliability need to be considered.

[0003] Since the internal space of the primary circuit is huge, it takes a lot of time to fill it with liquid. Therefore, a large-displacement charging pump is used to fill the liquid to save experimental time, and then a booster pump is used to increase the hydraulic pressure in the primary circuit. However, the existing technology lacks the ability to monitor whether the primary circuit is filled with liquid, and is unable to monitor whether the minimum flow valve is switched (whether the second water outlet is open). Personnel are required to monitor on-site, which increases the radiation dose of on-site personnel. At the same time, the switching process of the booster system is slow, and the test efficiency is low. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a nuclear power plant primary circuit water pressure test boosting system and a switching method, aiming to solve the problem of lack of automatic detection and automatic switching of the boosting system in the prior art.

[0005] The technical solution adopted by the present invention to solve its technical problems includes: a first charging pump, a booster liquid supply unit, a recovery unit, a first minimum flow valve, a water filling pipeline and a control unit; the booster liquid supply unit includes a booster pump and a first control valve; the recovery unit includes a first flow meter and a capacity control box; the first minimum flow valve includes a water inlet, a first water outlet and a second water outlet; the control unit is electrically connected to the first charging pump, the booster pump, the first control valve and the first flow meter; wherein, the first charging pump is connected to the water inlet through a pipeline, the first water outlet is connected to the water filling pipeline, the booster pump and the first control valve are connected in parallel to the water filling pipeline to form a first water path; the first charging pump is connected to the water inlet through a pipeline, the second water outlet is connected to the capacity control box, the capacity control box is connected back to the first charging pump through a pipeline, and the first flow meter is connected to the second water outlet and the pipeline of the capacity control box to form a second water path.

[0006] In one embodiment, the nuclear power plant primary circuit water pressure test boosting system also includes a second charging pump and a second minimum flow valve. The second flushing pump is connected to the second minimum flow valve through a pipeline and is connected in parallel to the water filling pipeline. The second minimum flow valve is also connected in parallel to the pipeline between the second water outlet and the control box.

[0007] In one embodiment, a first one-way valve and a second control valve are provided at the second water outlet of the first minimum flow valve, and a second one-way valve and a third control valve are provided on a pipeline connecting the second minimum flow valve and the second water outlet in parallel.

[0008] In one embodiment, a third one-way valve and a fourth control valve are further provided on the pipeline from the first flow meter to the control box.

[0009] In one embodiment, a fifth control valve and a second flow meter are provided at one end of the water filling pipeline away from the parallel connection point of the booster pump.

[0010] In one embodiment, the first charging pump and the second charging pump are centrifugal pumps, and the booster pump is a three-plunger pump.

[0011] The present invention also discloses a nuclear power plant primary circuit water pressure test boosting system, comprising the following steps:

[0012] Step S1, the control unit controls the first charging pump to start, the pressure at the first water outlet of the first minimum flow valve is less than the specified hydraulic pressure, so the first water outlet of the first minimum flow valve is opened, the second water outlet is closed, and the first charging pump supplies liquid into the water filling pipe;

[0013] Step S2, when the hydraulic pressure in the water-filled pipe reaches the specified pressure of the first minimum flow valve, the second water outlet of the first minimum flow valve will open, and a small amount of liquid will flow into the control box from the second water path. The first flow meter detects the flow and feeds back to the control unit;

[0014] Step S3, the control unit starts the booster pump, the control unit controls the first control valve to open, and the booster pump supplies liquid into the water filling pipe, completing the switching of the booster system.

[0015] In one embodiment, in step S3, the hydraulic pressure output by the booster pump is much greater than the specified pressure of the first minimum flow valve, the first water outlet is in a closed state, the second water outlet is in an open state, and the first charging pump supplies liquid to the second water circuit.

[0016] In one embodiment, after the booster pump is started, the first charging pump is continuously started to supply liquid.

[0017] In one embodiment, the first charging pump continuously supplies liquid to the volume control box, and the volume control box is connected to the first charging pump through a pipeline to form a circulation.

[0018] The implementation of the present invention has the following beneficial effects: the first charging pump is started to supply liquid to a circuit, and the first water outlet of the minimum flow valve is kept open. After the circuit is filled with liquid, after the hydraulic pressure at the first water outlet of the minimum flow valve reaches a specified value, the second water outlet is opened, and the liquid flows into the second water channel. Then the first flow meter detects the liquid flow and feeds back a signal to the control unit. The control unit determines that the hydraulic pressure in the circuit has reached the specified value of the minimum flow valve pressure at this time, and the control unit starts the booster pump, and the booster pump starts to boost the pressure in the circuit, thereby completing the switching of the booster system. The entire process can be detected by the first flow meter to know whether the system switching conditions are met in the circuit and the system automatically starts switching. The entire process does not require additional manual operation, and there is no need for personnel to enter the high radiation dose area for manual detection and switching, which greatly improves work efficiency and personnel health and safety levels. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solution of the present invention, the present invention will be further described below in conjunction with the accompanying drawings and embodiments. It should be understood that the following drawings only show certain embodiments of the present invention and should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work. In the drawings:

[0020] Figure 1 It is an overall diagram of a switching method of a primary circuit hydraulic test boosting system of a nuclear power plant in one embodiment of the present invention;

[0021] Figure 2 It is a flowchart of a method for switching a boosting system of a primary circuit water pressure test in a nuclear power plant in one embodiment of the present invention.

[0022] Figure Annotation

[0023] 100, first charging pump; 110, third flow meter; 120, first minimum flow valve; 130, second control valve; 140, first non-return valve; 150, seventh control valve; 160, first circulation non-return valve; 170, first circulation valve; 200, booster pump; 210, first control valve; 220, fifth control valve; 230, second flow meter; 300, second charging pump; 310, fourth flow meter; 320, fourth non-return valve; 330, sixth control valve; 340, second minimum flow valve; 350, eighth flow valve; 360, second circulation non-return valve; 370, second circulation valve; 400, volume control box; 410, volume control valve; 420, output non-return valve; 430, first flow meter; 440, fourth control valve; 450, third non-return valve; 500, water filling pipeline. DETAILED DESCRIPTION

[0024] In order to have a clearer understanding of the technical features, purposes and effects of the present invention, the specific embodiments of the present invention are now described in detail with reference to the accompanying drawings. In the following description, it should be understood that the directions or positional relationships indicated by "front", "back", "up", "down", "left", "right", "longitudinal", "horizontal", "vertical", "horizontal", "top", "bottom", "inside", "outside", "head", "tail", etc. are based on the directions or positional relationships shown in the accompanying drawings, are constructed and operated in a specific direction, and are only for the convenience of describing the present technical solution, rather than indicating that the device or element referred to must have a specific direction, and therefore cannot be understood as a limitation to the present invention.

[0025] It should also be noted that, unless otherwise clearly specified and limited, the terms such as "installed", "connected", "connected", "fixed", "set" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. When an element is referred to as being "on" or "under" another element, the element can be "directly" or "indirectly" located on the other element, or there may be one or more intermediate elements. The terms "first", "second", "third", etc. are only for the convenience of describing the present technical solution, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first", "second", "third", etc. can explicitly or implicitly include one or more of the features. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances.

[0026] Figure 1The invention shows a method for switching a boosting system for a primary water pressure test in a nuclear power plant in an embodiment of the present invention. The boosting system for a primary water pressure test in a nuclear power plant and the switching method can be used for switching a boosting system for a primary water pressure test in a nuclear power plant. The boosting system may include a first charging pump 100, a boosting liquid supply unit, a recovery unit, a first minimum flow valve 120, a water filling pipeline 500 and a control unit; the boosting liquid supply unit includes a boosting pump 200 and a first control valve 210; the recovery unit includes a first flow meter 430 and a control box 400; the first minimum flow valve 120 includes a water inlet, a first water outlet and a second water outlet; the control unit The element is electrically connected to the first charging pump 100, the booster pump 200, the first control valve 210, and the first flow meter 430; wherein, the first charging pump 100 is connected to the water inlet through a pipeline, the first water outlet is connected to the water filling pipeline 500, the booster pump 200 and the first control valve 210 are connected in parallel to the water filling pipeline 500 to form a first water circuit; the first charging pump 100 is connected to the water inlet through a pipeline, the second water outlet is connected to the control box 400, the control box 400 is connected back to the first charging pump 100 through a pipeline, and the first flow meter 430 is connected to the second water outlet and the pipeline of the control box 400 to form a second water circuit. Start the first charging pump 100 to supply liquid to the first circuit, and keep the first water outlet of the minimum flow valve open. After the first circuit is filled with liquid, the hydraulic pressure at the first water outlet of the minimum flow valve reaches the specified value, and then the second water outlet opens, and the liquid flows into the second water channel. Then the first flow meter 430 detects the liquid flow and feeds the signal back to the control unit. The control unit determines that the first circuit is now filled with liquid, and starts the booster pump 200. The booster pump 200 starts to boost the pressure in the first circuit, thereby completing the switching of the booster system. The whole process can be known through the detection of the first flow meter 430 whether the specified pressure in the first circuit has been reached and the system automatically starts switching. The whole process does not require additional manual operation, and there is no need for personnel to enter the high radiation dose area for manual detection and switching, which greatly improves work efficiency and personnel health and safety.

[0027] In a specific embodiment, the specific output pressure of the booster pump 200 needs to be determined according to the actual primary circuit design and the requirements of the water pressure test.

[0028] In a specific embodiment, the output pressure of the booster pump 200 is 1 MPa to 26 MPa.

[0029] In a specific embodiment, the minimum flow valve is a three-way valve, the water inlet of the minimum flow valve is connected to the first charging pump 100, and the first water outlet and the second water outlet are switches between two states. In state one, the hydraulic pressure at the first water outlet is less than the specified value, the first water outlet is in an open state, and the second water outlet is in a closed state. At this time, the first charging pump 100 continues to flow through the minimum flow valve through the water filling pipe 500 and then reaches the space in the first circuit; in state two, the hydraulic pressure at the first water outlet is greater than the specified value. At this time, it can be assumed that the first circuit and the water filling pipe 500 are already full of liquid, and the boosting system can be switched. The first water outlet is in a closed state, and the second water outlet is in an open state. The first charging pump 100 continues to flow into the control box 400 through the minimum flow valve, and the control box 400 stores liquid.

[0030] It can be understood that the first control valve 210 is used to control the pipeline switch of the booster pump 200. Since the output pressure of the booster pump 200 is relatively high, the first control valve 210 is required to control it separately to avoid the booster pump 200 continuing to output to a circuit in the event of an unexpected situation, and the pipeline liquid supply can be cut off immediately.

[0031] Figure 1 It is shown that the primary-loop water pressure test boosting system of a nuclear power plant may include a second charging pump 300 and a second minimum flow valve 340 in one embodiment. The second flushing pump is connected to the second minimum flow valve 340 through a pipeline and is connected in parallel to the water filling pipeline 500. The second minimum flow valve 340 is also connected in parallel to the pipeline between the second water outlet and the control box 400. Two or more charging pumps can improve the liquid filling efficiency in the primary loop.

[0032] It is understandable that the number of charging pumps can be increased as needed to increase the filling efficiency of a circuit.

[0033] Figure 1 It is shown that the first minimum flow valve 120 may include, in one embodiment, a first one-way valve 140 and a second control valve 130 provided at the second water outlet of the first minimum flow valve 120, a second one-way valve and a third control valve provided on the pipeline in parallel with the second water outlet of the second minimum flow valve 340, the first one-way valve 140 can prevent the liquid from flowing back, and avoid the liquid rebound at the second water outlet from damaging the minimum flow valve, the third control valve is connected to the control unit, and the third control valve can control the opening and closing of the second liquid outlet pipeline, so as to facilitate the control of the entire pipeline.

[0034] Figure 1 It is shown that in one embodiment, the control box 400 may include a third one-way valve 450 and a fourth control valve 440 provided on the pipeline from the first flow meter 430 to the control box 400. The fourth control valve 440 is mainly used to control the joint input of liquid after a plurality of charging pumps are connected in parallel, and serves as a pipeline valve for the overall control of the flow into the control box 400.

[0035] Figure 1 It is shown that in one embodiment, the water filling pipeline 500 may include a fifth control valve 220 and a second flow meter 230 at one end of the water filling pipeline 500 away from the parallel connection of the booster pump 200, and the fifth control valve 220 is used to control the total output of the water filling pipeline 500.

[0036] In a specific embodiment, a sixth control valve 330 and a fourth check valve 320 are provided in parallel at the second minimum flow valve 340 and the control box 400 , and the sixth control valve 330 is used to control the flow switch of the second minimum flow valve 340 flowing into the control box 400 .

[0037] In a specific embodiment, a volume control valve 410 and an output check valve 420 are further provided on the output pipeline of the volume control box 400 for controlling the liquid output of the volume control box 400 .

[0038] In a specific embodiment, the pipeline of the control box 400 is divided into two branches, which are respectively connected to the first charging pump 100 and the second charging pump 300. The first charging pump 100 is connected to the first circulation valve 170 and the first circulation check valve 160, and the second charging pump 300 is connected to the second circulation valve 370 and the second circulation check valve 360.

[0039] In a specific embodiment, a third flow meter 110 is further provided at the first charging pump 100 for measuring the flow output by the first charging pump 100 .

[0040] In a specific embodiment, a fourth flow meter 310 is further provided at the second charging pump 300 for measuring the flow output by the second charging pump 300 .

[0041] In a specific embodiment, a seventh control valve 150 is provided at the place where the first minimum flow valve 120 is connected to the water filling pipeline 500, and the seventh control valve 150 is used to control the switch control of the output of the first charging pump 100 to a circuit.

[0042] In a specific embodiment, an eighth control valve is provided at the place where the second minimum flow valve 340 is connected to the water filling pipeline 500, and the eighth control valve is used to control the switch control of the second charging pump 300 output to the primary circuit.

[0043] Figure 1 It is shown that in one embodiment, the first charging pump 100 and the second charging pump 300 may include the first charging pump 100 and the second charging pump 300 are centrifugal pumps with large displacement, and the booster pump 200 is a three-plunger pump to increase the pressure output, and the output pressure is stable.

[0044] Figure 2 A nuclear power plant primary circuit water pressure test boosting system in one embodiment of the present invention is shown, comprising the following steps:

[0045] Step S1, the control unit controls the first charging pump 100 to start, the pressure at the first water outlet of the first minimum flow valve 120 is less than the specified hydraulic pressure, so the first water outlet of the first minimum flow valve 120 is opened, the second water outlet is closed, and the first charging pump 100 supplies liquid to the water filling pipe 500;

[0046] Step S2, when the hydraulic pressure in the water-filled pipe 500 reaches the specified pressure of the first minimum flow valve 120, the second water outlet of the first minimum flow valve 120 will open, and a small amount of liquid will flow into the control box 400 from the second water path. The first flow meter 430 detects the flow and feeds back to the control unit;

[0047] Step S3, the control unit starts the booster pump 200, controls the first control valve 210 to open, and the booster pump 200 supplies liquid to the water filling pipe 500, completing the switching of the booster system.

[0048] Figure 2 Step S3 in one embodiment may include that the hydraulic pressure output by the booster pump 200 is much greater than the specified pressure of the first minimum flow valve 120, the first water outlet is in a closed state, the second water outlet is in an open state, and the first charging pump 100 supplies liquid to the second water circuit.

[0049] Figure 1 and Figure 2 Step S3 in one embodiment may include that after the booster pump 200 is started, the first charging pump 100 is continuously started to supply liquid. The first charging pump 100 continues to supply liquid. When the hydraulic pressure in a circuit changes suddenly, such as a valve opening somewhere, the first water outlet will change due to pressure, causing the first charging pump 100 to supply liquid into the water filling pipe 500 to prevent the internal liquid from dropping and forming gaps.

[0050] Figure 1 and Figure 2 In one embodiment, step S3 may include the first charging pump 100 continuously supplying liquid into the control box 400 , and the control box 400 is connected to the first charging pump 100 through a pipeline to form a circulation.

[0051] It can be understood that the above embodiments only express the preferred implementation modes of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the patent scope of the present invention. It should be pointed out that, for ordinary technicians in this field, without departing from the concept of the present invention, the above technical features can be freely combined, and several deformations and improvements can be made, which all belong to the protection scope of the present invention. Therefore, all equivalent changes and modifications made to the scope of the claims of the present invention should belong to the scope covered by the claims of the present invention.

Claims

1. A nuclear power plant primary circuit hydraulic test booster system, characterized in that: include: A first charging pump (100), a pressure-boosting liquid supply unit, a recovery unit, a first minimum flow valve (120), a water filling pipeline (500) and a control unit; The boosting liquid supply unit comprises a boosting pump (200) and a first control valve (210); The recovery unit comprises a first flow meter (430) and a volume control box (400); The first minimum flow valve (120) comprises a water inlet, a first water outlet and a second water outlet; The control unit is electrically connected to the first charging pump (100), the booster pump (200), the first control valve (210), and the first flow meter (430); The first charging pump (100) is connected to the water inlet via a pipeline, the first water outlet is connected to the water filling pipeline (500), the booster pump (200) and the first control valve (210) are connected in parallel to the water filling pipeline (500) to form a first water circuit; the first charging pump (100) is connected to the water inlet via a pipeline, the second water outlet is connected to the control box (400), the control box (400) is connected back to the first charging pump (100) via a pipeline, and the first flow meter (430) is connected to the second water outlet and the pipeline of the control box (400) to form a second water circuit.

2. The nuclear power plant primary circuit water pressure test boosting system according to claim 1, characterized in that: The nuclear power plant primary circuit water pressure test boosting system also includes a second charging pump (300) and a second minimum flow valve (340). The second flushing pump is connected to the second minimum flow valve (340) through a pipeline and is connected in parallel to the water filling pipeline (500). The second minimum flow valve (340) is also connected in parallel to the pipeline between the second water outlet and the control box (400).

3. The nuclear power plant primary circuit water pressure test boosting system according to claim 2, characterized in that: A first one-way valve (140) and a second control valve (130) are provided at the second water outlet of the first minimum flow valve (120), and a second one-way valve and a third control valve are provided on a pipeline connected in parallel between the second minimum flow valve (340) and the second water outlet.

4. The nuclear power plant primary circuit water pressure test boosting system according to claim 2, characterized in that: A third one-way valve (450) and a fourth control valve (440) are also provided on the pipeline from the first flow meter (430) to the volume control box (400).

5. The nuclear power plant primary circuit water pressure test boosting system according to claim 1, characterized in that: A fifth control valve (220) and a second flow meter (230) are provided at one end of the water filling pipeline (500) away from the parallel connection point of the booster pump (200).

6. The nuclear power plant primary circuit water pressure test boosting system according to claim 2, characterized in that: The first charging pump (100) and the second charging pump (300) are centrifugal pumps, and the booster pump (200) is a three-plunger pump.

7. A switching method for a primary circuit water pressure test boosting system of a nuclear power plant, applied to a primary circuit water pressure test boosting system of a nuclear power plant according to any one of claims 1 to 6, characterized in that: The following steps are involved: Step S1, the control unit controls the first charging pump (100) to start, the pressure at the first water outlet of the first minimum flow valve (120) is less than the specified hydraulic pressure, so the first water outlet of the first minimum flow valve (120) is opened, the second water outlet is closed, and the first charging pump (100) supplies liquid into the water filling pipeline (500); Step S2, when the hydraulic pressure in the water-filled pipe (500) reaches the specified pressure of the first minimum flow valve (120), the second water outlet of the first minimum flow valve (120) will open, and a small amount of liquid will flow into the control box (400) from the second water path, and the first flow meter (430) will detect the flow and feed it back to the control unit; In step S3, the control unit starts the booster pump (200), controls the first control valve (210) to open, and the booster pump (200) supplies liquid into the water filling pipe (500), thereby completing the switching of the booster system.

8. The method for switching the primary circuit hydraulic test boosting system of a nuclear power plant according to claim 7, characterized in that: In step S3, the hydraulic pressure output by the booster pump (200) is much greater than the specified pressure of the first minimum flow valve (120), the first water outlet is in a closed state, the second water outlet is in an open state, and the first charging pump (100) supplies liquid to the second water circuit.

9. The method for switching the primary circuit hydraulic test boosting system of a nuclear power plant according to claim 8, characterized in that: After the booster pump (200) is started, the first charging pump (100) is started continuously to supply liquid.

10. The method for switching the primary circuit water pressure test boosting system of a nuclear power plant according to claim 8, characterized in that: The first charging pump (100) continuously supplies liquid to the volume control box (400), and the volume control box (400) is connected to the first charging pump (100) through a pipeline to form a circulation.

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