A device for pressure relief and verification of the hermeticity test of the containment of a nuclear power unit

Abstract

The present invention belongs to the technical field of containment sealability detection for nuclear power plants, and particularly relates to a device for pressure relief and verification of the containment sealability test of a nuclear power unit. The device includes a buffer elbow, a flange-type triple-eccentric multi-layer metal-sealed butterfly valve I, a union screw thread, a flange-type triple-eccentric multi-layer metal-sealed butterfly valve II, a manual ball valve for the main path of the verification test, a four-way valve, a manual ball valve for the branch path of the sealability test, a manual ball valve for the main acquisition branch path of the verification test, a mass flow controller I, a manual ball valve for the secondary acquisition branch path of the verification test, a mass flow controller II, a connecting hose, and a connecting straight pipe. The device provided by the present invention can effectively divert and buffer the pressure relief airflow in the containment sealability test of a nuclear power unit, achieving the purpose of protecting surrounding equipment and instruments; and can adjust the small-flow pressure relief condition as needed for carrying out the verification test of the containment sealability test of a nuclear power unit.

Description

Technical Field

[0001] The present invention belongs to the technical field of containment seal detection for nuclear power plants, and particularly relates to a device for pressure relief and verification of the containment seal test for nuclear power units. Background Art

[0002] The containment seal test is achieved by supplying compressed air into the containment by a compressor, aiming to determine whether the containment and its components can meet the requirements of their design performance during the life cycle of the nuclear power plant after processing, commissioning, maintenance, and regular inspections. After the test, the air needs to be released into the interlayer space and then discharged into the atmosphere through the system filter. However, in the Russian design, the pressure relief port is only an upward flange blind plate, without considering the functions of slow-flow pressure relief and verification tests.

[0003] According to the requirements of the ANSI-56.8-2002 standard, the results of the containment seal test should be confirmed by the performance of the verification test. The key to the verification test is to measure a stable superimposed leakage rate. Therefore, a pressure relief port that can generate a stable small flow rate is required as the verification test interface. There are many equipment and instruments above the pressure relief port. The impact of compressed air containing a large amount of water vapor and aerosol during the pressure relief process will damage the equipment and instruments above. Moreover, the containment seal test occupies the critical path of the power plant overhaul. It is necessary to ensure that a large flow of gas passes through during pressure relief. Therefore, it is necessary to divert and buffer the air at the pressure relief port to avoid a large amount of gas directly impacting the equipment and instruments.

[0004] Therefore, it is necessary to design a device for pressure relief and verification of the containment seal test for nuclear power units, which can take into account both pressure relief buffering and verification tests, divert and buffer the large flow of gas in the containment, and conduct a small flow verification test for measuring the leakage rate of the containment to solve the deficiencies of the prior art. Summary of the Invention

[0005] The purpose of the present invention is to provide a device for pressure relief and verification of the containment seal test for nuclear power units in view of the above-mentioned deficiencies of the prior art, so as to achieve the purpose of realizing the functions of pressure relief buffering and verification test in the containment seal test.

[0006] The technical solution of the present invention is as follows:

[0007] A device for pressure relief and verification in the containment seal test of a nuclear power unit. The device includes a buffer elbow, a flange type triple eccentric multi-layer metal seal butterfly valve I, a union screw thread, a flange type triple eccentric multi-layer metal seal butterfly valve II, a main verification test path manual ball valve, a four-way valve, a seal test branch manual ball valve, a main verification test acquisition branch manual ball valve, a mass flow controller I, a secondary verification test acquisition branch manual ball valve, a mass flow controller II, a connecting hose, and a connecting straight pipe. The buffer elbow, the flange type triple eccentric multi-layer metal seal butterfly valve I, the connecting straight pipe, and the flange type triple eccentric multi-layer metal seal butterfly valve II are sequentially flange-connected to form a diversion channel. One end of the main verification test path manual ball valve is connected to the union screw thread formed by drilling a hole in the connecting straight pipe, and the other end is connected to the seal test branch manual ball valve, the main verification test acquisition branch manual ball valve, and the secondary verification test acquisition branch manual ball valve through the four-way valve.

[0008] The buffer elbow, the flange type triple eccentric multi-layer metal seal butterfly valve I, the union screw thread, the flange type triple eccentric multi-layer metal seal butterfly valve II, and the connecting straight pipe form a low-precision large-flow pressure relief buffer system.

[0009] The buffer elbow, the flange type triple eccentric multi-layer metal seal butterfly valve I, the union screw thread, the flange type triple eccentric multi-layer metal seal butterfly valve II, and the connecting straight pipe are made of 20 steel.

[0010] The buffer elbow is designed into a 45° bending structure.

[0011] The main verification test path manual ball valve, the four-way valve, the seal test branch manual ball valve, the main verification test acquisition branch manual ball valve, the mass flow controller I, the mass flow controller II, and the secondary verification test acquisition branch manual ball valve form a high-precision small-flow verification test system.

[0012] The other end of the seal test branch manual ball valve is connected to the connecting hose.

[0013] The other end of the main verification test acquisition branch manual ball valve is connected to the mass flow controller I.

[0014] The other end of the secondary verification test acquisition branch manual ball valve is connected to the mass flow controller II.

[0015] The present invention has the following beneficial effects:

[0016] The device provided by the present invention can effectively divert and buffer the pressure relief air flow in the containment seal test of a nuclear power unit, achieving the purpose of protecting surrounding equipment and instruments;

[0017] The device provided by the present invention can adjust the small-flow pressure relief condition as needed for carrying out the verification test of the containment seal test of a nuclear power unit;

[0018] The device provided by the present invention has a variable design and a wide range of applications. By modifying the interface between the device and the system, it can be applied to the field of containment seal tests for nuclear power units, and has great popularization value. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic structural diagram of a device designed by the present invention for pressure relief and verification of the containment seal of a nuclear power unit;

[0020] Wherein: 1 - inner wall of the containment, 2 - buffer elbow, 3 - first flanged triple-eccentric multi-layer metal seal butterfly valve, 4 - union screw thread, 5 - second flanged triple-eccentric multi-layer metal seal butterfly valve, 6 - manual ball valve for the main verification test path, 7 - four-way valve, 8 - manual ball valve for the leak test branch, 9 - manual ball valve for the main acquisition branch of the verification test, 10 - first mass flow controller, 11 - manual ball valve for the secondary acquisition branch of the verification test, 12 - second mass flow controller, 13 - connecting hose, 14 - original pressure relief port elbow, 15 - sealing flange, 16 - connecting straight pipe DETAILED DESCRIPTION OF THE INVENTION

[0021] The following further describes the technology of the present invention:

[0022] As Figure 1 shown, a device for pressure relief and verification of the containment seal of a nuclear power unit, the device includes a buffer elbow 2, a first flanged triple-eccentric multi-layer metal seal butterfly valve 3, a union screw thread 4, a second flanged triple-eccentric multi-layer metal seal butterfly valve 5, a manual ball valve 6 for the main verification test path, a four-way valve 7, a manual ball valve 8 for the leak test branch, a manual ball valve 9 for the main acquisition branch of the verification test, a first mass flow controller 10, a manual ball valve 11 for the secondary acquisition branch of the verification test, a second mass flow controller 12, a connecting hose 13 and a connecting straight pipe 16.

[0023] The connection of this device is divided into three parts, namely the containment body pressure relief system, the low-precision large-flow pressure relief buffer system and the high-precision small-flow verification test system. The sealing flange 15 of the containment body pressure relief system is flange-connected to the flanged triple-eccentric multi-layer metal seal butterfly valve 5 of the low-precision large-flow pressure relief buffer system, and the union screw thread 4 of the low-precision large-flow pressure relief buffer system is connected to the manual ball valve 6 of the main verification test path of the high-precision small-flow verification test system by means of a quick hose connection.

[0024] The inner wall of the containment, the original relief elbow 14, and the sealing flange 15 form the containment body relief system. The original relief elbow 14 is a penetrator of the inner wall of the containment, used to discharge the compressed air inside the containment. The sealing flange 15 is connected to the original relief elbow 14 by welding. In the non-test state, the system is closed by connecting a flange blind plate to the sealing flange 15. In the test state, the flange blind plate is opened, and a low-precision large-flow relief buffer system is connected to the containment body relief system.

[0025] The buffer elbow 2, the flange type triple eccentric multi-layer metal sealed butterfly valve 3, the union screw port 4, the flange type triple eccentric multi-layer metal sealed butterfly valve 5, and the connecting straight pipe 16 form the low-precision large-flow relief buffer system. The buffer elbow 2, the flange type triple eccentric multi-layer metal sealed butterfly valve 3, the connecting straight pipe 16, and the flange type triple eccentric multi-layer metal sealed butterfly valve 5 are sequentially connected by flanges to form a diversion channel, and finally connected to the sealing flange 15 through the flange type triple eccentric multi-layer metal sealed butterfly valve 5 and fixed with bolts. A union screw port 4 is formed by drilling a hole in the connecting straight pipe 16 for connecting the high-precision small-flow verification test system. One of the key features is that a connecting straight pipe 16 is installed between the flange type triple eccentric multi-layer metal sealed butterfly valve 3 and the flange type triple eccentric multi-layer metal sealed butterfly valve 5, which can provide a large sealing space to ensure the stability and accuracy of small-flow gas measurement. Another key feature is that the relief buffer system and the containment body relief system are made of the same material, 20 steel, and the elbow is designed at 45° to direct the original upward air flow towards the inner wall.

[0026] The verification test main path manual ball valve 6, the four-way valve 7, the sealing test branch manual ball valve 8, the verification test main acquisition branch manual ball valve 9, the mass flow controller one 10, the mass flow controller two 12, and the verification test slave acquisition branch manual ball valve 11 form the high-precision small-flow verification test system. The high-precision small-flow verification test system connects the verification test main path manual ball valve 6 to the union screw port 4 of the low-precision large-flow relief buffer system through a hose. The four-way valve 7 is used to connect the verification test main path manual ball valve 6, the sealing test branch manual ball valve 8, the verification test main acquisition branch manual ball valve 9, and the verification test slave acquisition branch manual ball valve 11. One end of the connecting hose 13 is connected to the sealing test branch manual ball valve 8, and the other end is connected to the leak detection device for leak inspection. The verification test main acquisition branch manual ball valve 9 is quickly connected to the mass flow controller one 10 through a hose as the verification test main acquisition measurement channel, and the verification test slave acquisition branch manual ball valve 11 is quickly connected to the mass flow controller two 12 through a hose as the verification test slave acquisition measurement channel. One of the key features is that after the verification test main acquisition branch manual ball valve 9 and the verification test slave acquisition branch manual ball valve 11, mass flow controllers are connected respectively to form the main acquisition and slave acquisition two-way verification test channels, which improves the fault tolerance rate and system reliability of the system.

[0027] The invention adopts a 90° pipeline for drainage, which changes the flow direction of the pressure-relieving gas, causing the pressure-relieving gas to impact the wall surface and disperse, thereby reducing the risk of the pressure-relieving airflow damaging the surrounding equipment.

[0028] The invention adopts a double-sealed valve to isolate a small-flow channel with good sealing performance for verification tests, and designs a corresponding flow measurement function to achieve the function of performing verification tests.

[0029] The invention combines the large-flow condition of pressure relief and the small-flow condition of verification tests to ensure the continuity of the test execution process and the simplicity of operation.

[0030] The present invention has been described in detail above in conjunction with the embodiments. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those of ordinary skill in the art, various changes can be made without departing from the gist of the present invention. The content not described in detail in the present invention can all adopt the prior art.

Claims

1. A device for pressure relief and verification of the containment seal tightness test of a nuclear power unit, characterized in that: The device includes a buffer elbow (2), a flange type triple eccentric multi-layer metal seal butterfly valve I (3), a union screw port (4), a flange type triple eccentric multi-layer metal seal butterfly valve II (5), a manual ball valve for the main path of the verification test (6), a four-way valve (7), a manual ball valve for the branch path of the seal tightness test (8), a manual ball valve for the main acquisition branch path of the verification test (9), a mass flow controller I (10), a manual ball valve for the slave acquisition branch path of the verification test (11), a mass flow controller II (12), a connecting hose (13) and a connecting straight pipe (16). The buffer elbow (2), the flange type triple eccentric multi-layer metal seal butterfly valve I (3), the connecting straight pipe (16) and the flange type triple eccentric multi-layer metal seal butterfly valve II (5) are sequentially flange-connected to form a diversion channel. One end of the manual ball valve for the main path of the verification test (6) is connected to the union screw port (4) formed by opening a hole on the connecting straight pipe (16), and the other end is connected to the manual ball valve for the branch path of the seal tightness test (8), the manual ball valve for the main acquisition branch path of the verification test (9), and the manual ball valve for the slave acquisition branch path of the verification test (11) through the four-way valve (7).

2. The device for pressure relief and verification of the containment seal tightness test of a nuclear power unit according to claim 1, characterized in that: The buffer elbow (2), the flange type triple eccentric multi-layer metal seal butterfly valve I (3), the union screw port (4), the flange type triple eccentric multi-layer metal seal butterfly valve II (5) and the connecting straight pipe (16) form a low-precision large-flow pressure relief buffer system.

3. The device for pressure relief and verification of the containment seal tightness test of a nuclear power unit according to claim 2, characterized in that: The buffer elbow (2), the flange type triple eccentric multi-layer metal seal butterfly valve I (3), the union screw port (4), the flange type triple eccentric multi-layer metal seal butterfly valve II (5) and the connecting straight pipe (16) are made of 20 steel.

4. The device for pressure relief and verification of the containment seal tightness test of a nuclear power unit according to claim 3, characterized in that: The buffer elbow (2) is designed into a 45° bending structure.

5. The device for pressure relief and verification of the containment seal tightness test of a nuclear power unit according to claim 4, characterized in that: The manual ball valve for the main path of the verification test (6), the four-way valve (7), the manual ball valve for the branch path of the seal tightness test (8), the manual ball valve for the main acquisition branch path of the verification test (9), the mass flow controller I (10) and the mass flow controller II (12), and the manual ball valve for the slave acquisition branch path of the verification test (11) form a high-precision small-flow verification test system.

6. The device for pressure relief and verification of the containment seal tightness test of a nuclear power unit according to claim 5, characterized in that: The other end of the manual ball valve for the branch path of the seal tightness test (8) is connected to the connecting hose (13).

7. The device for pressure relief and verification of the containment seal tightness test of a nuclear power unit according to claim 6, characterized in that: The other end of the manual ball valve (9) of the main acquisition branch of the verification test is connected to the first mass flow controller (10).

8. A device for pressure relief and verification of the containment sealability test of a nuclear power unit according to claim 7, characterized in that: The other end of the manual ball valve (11) of the acquisition branch from the verification test is connected to the second mass flow controller (12).

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