An online water filling system for nuclear power plant heat exchangers after maintenance

Abstract

This invention belongs to the field of online water filling technology after nuclear power plant heat exchanger maintenance, specifically relating to an online water filling system for nuclear power plant heat exchangers after maintenance. The invention includes a No. 1 heat exchanger and a No. 2 heat exchanger, which are connected in parallel via pipelines. The inlet ends of the parallel pipelines form two parallel loops: a flow loop and a bypass loop. It also includes a No. 1 cooling water pump and a No. 2 cooling water pump, which are connected in parallel. One end of the parallel loop of the No. 1 and No. 2 cooling water pumps is connected to the outlet end of the parallel pipeline of the No. 1 and No. 2 heat exchangers, and the other end is connected to the bypass loop via a user connection to the cooling water system. This invention can reduce the risk of human error during online water filling of nuclear power plant heat exchangers after maintenance, and improve the safety and reliability of the heat exchanger filling process.

Description

Technical Field

[0001] This invention belongs to the field of online water filling technology after nuclear power plant heat exchanger maintenance, and specifically relates to an online water filling system for nuclear power plant heat exchanger maintenance. Background Technology

[0002] Currently, online water filling of heat exchangers after maintenance is a high-risk operation at nuclear power plants both domestically and internationally during power operation. A nuclear power plant previously experienced a shutdown due to online water filling of heat exchangers after maintenance. The commonly used method is to slowly open the inlet or outlet electric valves of the heat exchanger. Because the inlet and outlet pipelines of the heat exchanger have large diameters, close cooperation between the control room operator and the field operator is required during this process. The control room operator needs to closely monitor relevant parameters such as the pressure difference between the heat exchanger inlet and outlet, the temperature after the heat exchanger, the inlet pressure of the cooling water pump, and the outlet pressure of the cooling water pump. The field operator needs to manually crank the inlet or outlet electric valves of the heat exchanger, which is extremely time-consuming and labor-intensive. Any communication breakdown, inaccurate valve position indication, or excessively rapid valve opening or closing can lead to low cooling water pump inlet pressure, potentially causing pump tripping, and even reactor shutdown. Summary of the Invention

[0003] The purpose of this invention is to address the shortcomings of existing water filling methods by providing an online water filling system for nuclear power plant heat exchangers after maintenance, thereby reducing the risk of human error during online water filling of nuclear power plant heat exchangers after maintenance and improving the safety and reliability of the water filling process.

[0004] The technical solution adopted in this invention is as follows:

[0005] An online water filling system for a nuclear power plant heat exchanger after maintenance includes a No. 1 heat exchanger and a No. 2 heat exchanger, which are connected in parallel via pipelines. The inlet ends of the parallel pipelines form two parallel loops: a flow loop and a bypass loop. The system also includes a No. 1 cooling water pump and a No. 2 cooling water pump, which are connected in parallel. One end of the parallel loop of the No. 1 and No. 2 cooling water pumps is connected to the outlet end of the parallel pipeline of the No. 1 and No. 2 heat exchangers, and the other end is connected to the bypass loop via a user connection of the cooling water system.

[0006] The outlets of the No. 1 heat exchanger and the No. 2 heat exchanger are connected by pipelines, and the pipelines are respectively equipped with the No. 1 heat exchanger outlet electric valve and the No. 2 heat exchanger outlet electric valve.

[0007] The flow circuit is equipped with a No. 1 heat exchanger inlet electric valve and a No. 2 heat exchanger inlet electric valve, respectively, and the bypass circuit is equipped with a regulating valve bypass electric valve one and a regulating valve bypass electric valve two.

[0008] The flow circuit and the bypass circuit are connected by a pipeline, and a temperature regulating valve is provided on the flow circuit.

[0009] An interface is provided on the pipeline between the No. 1 heat exchanger and the No. 1 heat exchanger inlet electric valve, and a pipeline is provided to connect the No. 2 heat exchanger and the No. 2 heat exchanger inlet electric valve. The connecting pipeline is provided with the No. 1 heat exchanger drain valve and the No. 2 heat exchanger drain valve.

[0010] The pipeline between the No. 1 heat exchanger drain valve and the No. 2 heat exchanger drain valve is provided with an interface, which is connected to one end of the heat exchanger drain manifold isolation valve. The other end of the heat exchanger drain manifold isolation valve is connected to the drain collection pit, the cooling water pump outlet exhaust pipeline, the nuclear island demineralized water supply system exhaust pipeline, the nuclear island equipment cooling water system safety valve drain pipeline, the heat exchanger user's exhaust pipeline, the heat exchanger user's drainage pipeline, the No. 2 heat exchanger exhaust pipeline, and the No. 1 heat exchanger exhaust pipeline.

[0011] The pipeline on one side of the No. 1 cooling water pump is equipped with a No. 1 cooling water pump inlet electric valve, a No. 1 cooling water pump outlet check valve, and a No. 1 cooling water pump outlet electric valve. The pipeline on the other side of the No. 2 cooling water pump is equipped with a No. 2 cooling water pump inlet electric valve, a No. 2 cooling water pump outlet check valve, and a No. 2 cooling water pump outlet electric valve.

[0012] An interface is provided on the pipeline between the outlet electric valve of heat exchanger No. 1 and the outlet electric valve of heat exchanger No. 2, and the pipeline is connected to the buffer tank. The buffer tank is connected to the demineralized water tank through the buffer tank water supply electric valve, and the buffer tank is equipped with a buffer tank level gauge.

[0013] The No. 1 heat exchanger is also connected to the No. 1 cooling water inlet pipeline and the No. 1 cooling water outlet pipeline, respectively, and the No. 2 heat exchanger is also connected to the No. 2 cooling water inlet pipeline and the No. 2 cooling water outlet pipeline, respectively, to ensure the circulation of the system's cold source.

[0014] The regulating valve bypass electric valve one, regulating valve bypass electric valve two, together with the regulating valve, are used to change the flow rate of the heat exchanger.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0016] (1) This invention provides an online water filling system for nuclear power plant heat exchangers after maintenance. It uses a small-diameter drainage pipeline of the operating heat exchanger to fill the nuclear power plant heat exchanger with water after maintenance. By adding isolation valves and changing the original layout of drainage and exhaust pipelines, the risk of reactor shutdown caused by online water filling of nuclear power plant heat exchangers after maintenance is greatly reduced, and the efficiency of online water filling of nuclear power plant heat exchangers after maintenance is greatly improved. The online water filling time of one nuclear power plant heat exchanger after maintenance is shortened from 120 minutes to 30 minutes.

[0017] (2) The present invention provides an online water filling system for nuclear power plant heat exchangers after maintenance, which improves the safety and reliability of the water filling process and reduces the probability of human error. Attached Figure Description

[0018] Figure 1 This invention provides a schematic diagram of an online water filling system for a nuclear power plant heat exchanger after maintenance.

[0019] In the diagram: 1-Heat Exchanger No. 1, 2-Heat Exchanger No. 2, 3-Cooling Water Pump No. 1, 4-Cooling Water Pump No. 2, 5-Cooling Water Inlet Pipeline No. 1, 6-Cooling Water Outlet Pipeline No. 1, 7-Steam Valve of Heat Exchanger No. 1, 8-Steam Valve of Heat Exchanger No. 2, 9-Buffer Tank, 10-Demineralized Water Tank, 11-Powered Water Supply Valve for Buffer Tank, 12-Powered Inlet Valve of Heat Exchanger No. 1, 13-Powered Inlet Valve of Heat Exchanger No. 2, 14-Powered Outlet Valve of Heat Exchanger No. 1, 15-Powered Outlet Valve of Heat Exchanger No. 2, 16-Isolation Valve for Heat Exchanger Drainage Manifold, 17-Steam Collection Pit, 18-Buffer Tank Level Gauge, 19-User of Cooling Water System, 20-Cooling Water Pump Outlet Exhaust Pipeline, 21-Exhaust Pipeline of Nuclear Island Demineralized Water Supply System, 22-Cooling Water Supply for Nuclear Island Equipment Water system safety valve drain line, 23-heat exchanger user exhaust line, 24-heat exchanger user drain line, 25-heat exchanger No. 2 exhaust line, 26-heat exchanger No. 1 exhaust line, 27-cooling water inlet line No. 2, 28-cooling water outlet line No. 2, ensuring the circulation of the system's cold source, 29-regulating valve bypass electric valve one, 30-regulating valve bypass electric valve two, 31-temperature regulating valve, 32-heat exchanger No. 1 exhaust valve, 33-heat exchanger No. 2 exhaust valve, 34-cooling water pump No. 1 inlet electric valve, 35-cooling water pump No. 2 inlet electric valve, 36-cooling water pump No. 1 outlet check valve, 37-cooling water pump No. 2 outlet check valve, 38-cooling water pump No. 1 outlet electric valve, 39-cooling water pump No. 2 outlet electric valve. Detailed Implementation

[0020] The following detailed description, in conjunction with the accompanying drawings and specific embodiments, provides an online water filling system for nuclear power plant heat exchangers after maintenance, based on the present invention.

[0021] like Figure 1 As shown, the present invention provides an online water filling system for a nuclear power plant heat exchanger after maintenance, comprising:

[0022] Heat exchanger 1 and heat exchanger 2 are used to cool the chemically demineralized water from the user's outlet and transfer the user's heat to the seawater.

[0023] The outlet ends of heat exchanger 1 and heat exchanger 2 are connected by pipelines, and the pipelines are respectively equipped with electric valve 14 for heat exchanger 1 and electric valve 15 for heat exchanger 2.

[0024] The inlet ends of heat exchanger 1 and heat exchanger 2 are connected by pipelines to form two parallel loops: a flow loop and a bypass loop. The flow loop is equipped with an electric valve 12 for the inlet of heat exchanger 1 and an electric valve 13 for the inlet of heat exchanger 2. The bypass loop is equipped with a regulating valve bypass electric valve 29 and a regulating valve bypass electric valve 30. The flow loop and the bypass loop are connected by pipelines. A temperature regulating valve 31 is provided on the flow loop.

[0025] An interface is provided on the pipeline between heat exchanger 1 and inlet electric valve 12 of heat exchanger 1, and it is connected to the pipeline between heat exchanger 2 and inlet electric valve 13 of heat exchanger 2. The connecting pipeline is equipped with heat exchanger 1 drain valve 7 and heat exchanger 2 drain valve 8.

[0026] Heat exchanger 1 is also connected to cooling water inlet line 5 and cooling water outlet line 6 respectively, and heat exchanger 2 is also connected to cooling water inlet line 27 and cooling water outlet line 28 respectively to ensure the circulation of the system's cold source.

[0027] The pipeline between the No. 1 heat exchanger drain valve 7 and the No. 2 heat exchanger drain valve 8 is equipped with an interface, which connects to one end of the heat exchanger drain manifold isolation valve 16. The other end of the heat exchanger drain manifold isolation valve 16 is connected to the drain collection pit 17, the cooling water pump outlet exhaust pipeline 20, the nuclear island demineralized water supply system exhaust pipeline 21, the nuclear island equipment cooling water system safety valve drain pipeline 22, the heat exchanger user's exhaust pipeline 23, the heat exchanger user's drainage pipeline 24, the No. 2 heat exchanger's exhaust pipeline 25, and the No. 1 heat exchanger's exhaust pipeline 26.

[0028] Cooling water pump 3 and cooling water pump 4 are connected in parallel to ensure the circulation of chemical demineralized water in the system. One end of the parallel circuit of cooling water pump 3 and cooling water pump 4 is connected to the pipeline between the electric valve 14 at the outlet of heat exchanger 1 and the electric valve 15 at the outlet of heat exchanger 2, and the other end is connected to the bypass circuit through the user 19 of the cooling water system. On the pipeline on the side of cooling water pump 3, electric valve 34 at the inlet of cooling water pump 3, check valve 36 at the outlet of cooling water pump 3, and electric valve 38 at the outlet of cooling water pump 3 are respectively installed. On the pipeline on the side of cooling water pump 4, electric valve 35 at the inlet of cooling water pump 4, check valve 37 at the outlet of cooling water pump 4, and electric valve 39 at the outlet of cooling water pump 4 are respectively installed.

[0029] An interface is provided on the pipeline between the outlet electric valve 14 of the No. 1 heat exchanger and the outlet electric valve 15 of the No. 2 heat exchanger, and the pipeline is connected to the buffer tank 9. The buffer tank 9 is connected to the demineralized water tank 10 through the buffer tank water supply electric valve 11. The buffer tank 9 is equipped with a buffer tank level gauge 18.

[0030] The No. 1 heat exchanger drain valve 7 is used for draining water from heat exchanger 1 and for online water filling after maintenance of heat exchanger 1 and heat exchanger 2.

[0031] The No. 2 heat exchanger drain valve 8 is used for draining water from heat exchanger 2 and for online water filling after maintenance of heat exchanger 1 and heat exchanger 2.

[0032] Buffer tank 9 is used for filling and replenishing the cooling water system of the nuclear island equipment, and maintaining the inlet pressure of cooling water pumps 1 and 2;

[0033] Demineralized water tank 10 is used to replenish water in buffer tank 9;

[0034] The buffer tank water replenishment electric valve 11 is used to control the water replenishment of the buffer tank 9;

[0035] The electric valve 12 at the inlet of heat exchanger 1 and the electric valve 13 at the inlet of heat exchanger 2 are used for the isolation of heat exchanger 1 and heat exchanger 2.

[0036] The No. 1 heat exchanger outlet electric valve 14 and the No. 2 heat exchanger outlet electric valve 15 are used for the isolation of heat exchanger 1 and heat exchanger 2.

[0037] The heat exchanger drain manifold isolation valve 16 is used to isolate the drains from heat exchangers 1 and 2 from other users to prevent cross-contamination.

[0038] Drainage collection pit 17 is used to collect drainage;

[0039] Buffer tank level gauge 18 is used for displaying the liquid level in buffer tank 9;

[0040] The regulating valve bypass electric valve 29, the regulating valve bypass electric valve 30, and the regulating valve 31 are used together to change the flow rate of heat exchanger 1 and heat exchanger 2.

[0041] Temperature regulating valve 31 is used to regulate the flow rate through the heat exchanger, thereby regulating the outlet temperature of the heat exchanger.

[0042] The exhaust valve 32 for heat exchanger 1 and the exhaust valve 33 for heat exchanger 2 are used for venting heat exchangers 1 and 2.

[0043] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A post maintenance on-line water charging system for a heat exchanger of a nuclear power plant, characterized in that: It includes a first heat exchanger (1), a second heat exchanger (2), the first heat exchanger (1) and the second heat exchanger (2) are connected in parallel through pipelines, the inlet end of the parallel pipeline forms two parallel circuits through pipelines, a flow circuit and a bypass circuit, it also includes a first cooling water pump (3), a second cooling water pump (4), the first cooling water pump (3) and the second cooling water pump (4) are connected in parallel, one end of the first cooling water pump (3) and the second cooling water pump (4) is connected to the outlet end of the parallel pipeline of the first heat exchanger (1) and the second heat exchanger (2), and the other end is connected to the bypass circuit through a user (19) of a cooling water system. The outlet end of the first heat exchanger (1) and the second heat exchanger (2) is connected through a pipeline, and a first heat exchanger outlet electric valve (14) and a second heat exchanger outlet electric valve (15) are respectively arranged on the pipeline. A first heat exchanger inlet electric valve (12) and a second heat exchanger inlet electric valve (13) are respectively arranged on the flow circuit, and a bypass electric valve one (29) and a bypass electric valve two (30) are respectively arranged on the bypass circuit. The flow circuit and the bypass circuit are connected through a pipeline, and a temperature regulating valve (31) is arranged on the flow circuit. An interface is arranged on the pipeline between the first heat exchanger (1) and the first heat exchanger inlet electric valve (12), and the pipeline is connected to the pipeline between the second heat exchanger (2) and the second heat exchanger inlet electric valve (13), and a first heat exchanger drain valve (7) and a second heat exchanger drain valve (8) are arranged on the connecting pipeline. An interface is arranged on the pipeline between the first heat exchanger drain valve (7) and the second heat exchanger drain valve (8), one end of the interface is connected to a heat exchanger drainage header isolation valve (16), and the other end of the heat exchanger drainage header isolation valve (16) is connected to a drain collection pit (17), a cooling water pump outlet exhaust pipeline (20), a nuclear island desalted water supply system exhaust pipeline (21), a nuclear island equipment cooling water system safety valve drainage pipeline (22), a heat exchanger user exhaust pipeline (23), a heat exchanger user drainage pipeline (24), a second heat exchanger exhaust pipeline (25) and a first heat exchanger exhaust pipeline (26) respectively.

2. The online water charging system for a heat exchanger of a nuclear power plant after maintenance according to claim 1, characterized in that: A first cooling water pump inlet electric valve (34), a first cooling water pump outlet check valve (36) and a first cooling water pump outlet electric valve (38) are respectively arranged on the pipeline of one side of the first cooling water pump (3), and a second cooling water pump inlet electric valve (35), a second cooling water pump outlet check valve (37) and a second cooling water pump outlet electric valve (39) are respectively arranged on the pipeline of one side of the second cooling water pump (4).

3. A post maintenance on-line water charging system for a heat exchanger of a nuclear power plant according to claim 2, characterized in that: An interface is arranged on the pipeline between the first heat exchanger outlet electric valve (14) and the second heat exchanger outlet electric valve (15), the pipeline is connected to a buffer tank (9), the buffer tank (9) is connected to a desalted water tank (10) through a buffer tank water supplement electric valve (11), and a buffer tank liquid level meter (18) is arranged on the buffer tank (9).

4. The system according to claim 3, wherein: The first heat exchanger (1) is also connected with a first cooling water inlet pipeline (5) and a first cooling water outlet pipeline (6) respectively, and the second heat exchanger (2) is also connected with a second cooling water inlet pipeline (27) and a second cooling water outlet pipeline (28) respectively, so as to ensure the circulation of the system cold source.

5. A post maintenance in-service water charging system for a heat exchanger of a nuclear power plant according to claim 4, characterized in that: The adjusting valve bypass electric valve one (29), the adjusting valve bypass electric valve two (30), and the temperature adjusting valve (31) are used together to change the flow of the first heat exchanger (1) and the second heat exchanger (2).

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