Device and method for testing gas permeation of containment concrete under gas-thermal coupling effect

Abstract

The invention relates to the technical field of concrete gas permeation detection, and discloses a containment concrete gas permeation testing device and method under the gas-thermal coupling effect, and the containment concrete gas permeation testing device under the gas-thermal coupling effect comprises a machine body, a plurality of testing cavities formed in the top of the machine body, and test pieces arranged in the testing cavities; the air inlet is formed in the top of the machine body, the end cover is arranged at the top of the test cavity, the extrusion column is arranged at the bottom of the end cover and abuts against the test piece, the heating module is arranged in the machine body, and the sealing units are arranged in the test cavity. The triangular elastic sealing ring is driven to automatically bend and rotate by means of side wall extrusion when a test piece is inserted, a wedging effect is formed along the gradually-shrunk sealing part, and dynamic self-tightening sealing can be achieved without bolt pre-tightening or a hydraulic device.

Description

Technical Field

[0001] This invention relates to the field of concrete gas permeability testing technology, and in particular to a device and method for testing gas permeability in containment concrete under gas-thermal coupling. Background Technology

[0002] In nuclear power engineering, containment concrete must withstand gas-thermal coupling effects (such as high-pressure gas, high-temperature environment, and mechanical stress under accident conditions). Its gas permeability and structural integrity are directly related to nuclear safety. In existing technologies, traditional testing devices are difficult to accurately simulate multi-field coupling effects, and their sealing reliability and data accuracy are insufficient, which limits the study of the permeability and damage mechanisms of concrete under extreme conditions.

[0003] In nuclear power engineering, the containment concrete must withstand the coupled effects of gas (high-pressure gas), heat (high-temperature environment), and force (mechanical load). Its gas permeability is a key indicator for assessing nuclear safety. Existing gas-thermal coupling permeability testing devices face core challenges: traditional sealing relies on bolt pre-tightening or hydraulic devices, which require manual adjustment and are prone to uneven sealing due to operational errors. Under high pressure, the seals wear out quickly, and under high-temperature environments, rigid seals are prone to gaps due to thermal expansion and contraction, resulting in high leakage rates. They also cannot achieve self-sealing and seal self-adaptation during the testing process, and their sealing performance is insufficient. Summary of the Invention

[0004] Given the problems of existing technologies, such as the need for manual pre-tightening of traditional seals, the inability to achieve self-sealing and self-adaptive sealing, and high leakage rates, a gas permeation testing device for containment concrete under gas-thermal coupling was proposed.

[0005] Its purpose is to solve the sealing problem of existing devices, accurately test the gas permeability of containment concrete under gas-thermal coupling, and ensure nuclear safety.

[0006] The technical solution of the present invention is a gas permeation test device for containment concrete under gas-thermal coupling, comprising a body, a plurality of test chambers disposed on the top of the body, a specimen disposed in the test chamber, an air inlet disposed on the top of the body, an end cap disposed on the top of the test chamber, an extrusion column disposed on the bottom of the end cap, the extrusion column abutting against the specimen, and a heating module disposed in the body, and further comprising at least one sealing unit disposed inside the test chamber; The sealing unit includes a vent hole at the bottom of the test chamber, a support plate at the bottom of the vent hole, a specimen placed on the support plate, the outer edge and middle of the support plate being through-hole, a sealing part at the top of the vent hole, a sealing ring at the sealing part, the sealing ring being triangular in shape, a sliding surface at the top of the sealing ring being slidably connected to the top of the sealing part, a curved surface at the center of the sealing ring, an abutment surface at the bottom of the sealing ring being smoothly connected to the curved surface, a compression chamber inside the sealing ring, and a compression plate inside the compression chamber. The sealing ring is made of elastic rubber. The sealing part is an annular hole with a gradually decreasing spacing in the vertical direction and connected to the vent.

[0007] Furthermore, the curved surface and the abutting surface together form an S-shape, and the abutting surface abuts against the bottom of the sealing part.

[0008] Furthermore, the sealing unit also includes a push groove formed on the side of the sealing ring facing the vent, and the push groove is in the shape of a concave arc.

[0009] Furthermore, the extrusion chamber includes an extrusion groove formed inside the sealing ring. The extrusion groove is an arc shape that bends toward the center of the test chamber. A protrusion is provided on one side of the extrusion groove. One end of the extrusion plate matches the extrusion groove. The top of the extrusion plate is curved upward in the opposite direction to the bending direction of the extrusion groove.

[0010] Furthermore, in the initial state, the extrusion plate is always within the sealing section in the vertical direction.

[0011] Furthermore, triangular grooves are uniformly formed on one side of the sliding surface.

[0012] Furthermore, in the initial state, the side of the sealing ring near the center of the test chamber extends out of the inner wall of the test chamber.

[0013] Another objective of this invention is to provide a method for testing the gas permeability of containment concrete under gas-thermal coupling. The purpose is to achieve a high airtight connection between the specimen and the test chamber under gas-thermal coupling by automatically driving the sealing ring to bend and rotate and squeeze the extrusion plate when the specimen is inserted, combined with the dynamic extrusion of the push groove by high-pressure gas. This accurately simulates the permeability state of containment concrete under extreme conditions, ensures the reliability of sealing and the accuracy of data during the test, and provides an efficient and stable testing method for nuclear safety assessment.

[0014] To achieve the above objectives, the present invention provides the following technical solution: a method for testing gas permeability in containment concrete under gas-thermal coupling, comprising the following steps: Open the end cap, place the pre-prepared cylindrical specimen into the test chamber, and tighten the end cap to the top of the test chamber with bolts; As the cylindrical specimen slides into the test chamber, the side wall at the bottom of the specimen slides down and enters the sealing ring, squeezing one side of the sealing ring. This causes the sealing ring to bend downwards along the surface of the specimen, and the pressing plate is pressed down to bend towards one side of the specimen. This causes the end of the pressing plate to press against the bent part of the sliding surface. The greater the downward rotation of the entire sealing ring, the greater the pressing force of the pressing plate on the bent part of the sliding surface. After the specimen is in place, the machine body is opened for testing. High-pressure gas is introduced into the bottom of the specimen through the air inlet, and the heating module is started simultaneously. The extrusion column extrudes the top of the specimen to test the gas permeability of the specimen under the action of gas-thermal coupling.

[0015] Furthermore, when high-pressure gas is introduced, the high-pressure gas compresses the concave pushing groove through the vent.

[0016] Compared with the prior art, the present invention has the following beneficial effects: 1. By utilizing the sidewall compression during specimen insertion, the triangular elastic sealing ring is driven to automatically bend and rotate, forming a "wedge effect" along the tapering sealing section, achieving dynamic self-tightening sealing without the need for bolt pre-tightening or hydraulic devices. The deeper the specimen is inserted, the tighter the sealing ring is compressed, making it particularly suitable for high-pressure scenarios. This avoids the human error and component wear associated with traditional pre-tightening seals, significantly improving installation efficiency and sealing reliability.

[0017] 2. A three-stage seal is formed by radial bonding, axial gradient compression and mechanical lever reinforcement. The elastic sealing ring fits with the specimen to block radial leakage, the tapered structure of the sealing part forms an axial pressure gradient to reduce permeation, and the extrusion plate rotates to amplify the extrusion pressure to achieve mechanical reinforcement. Combined with the air pressure driven self-reinforcing effect of the push groove, the gas leakage rate can be reduced to a large extent, effectively meeting the complex sealing requirements under gas-thermal coupling.

[0018] 3. The elastic rubber material and S-shaped curved surface design allow the sealing ring to adapt to the thermal expansion of the specimen, processing errors, or vibration loads through deformation. The concave arc structure of the push groove utilizes high-pressure gas to dynamically adjust the sealing force, forming a linkage response between pressure and sealing force. Under multi-field coupling environments such as high temperature, high pressure, and mechanical vibration, it continuously maintains sealing stability, providing a key guarantee for the accurate testing of nuclear power plant containment concrete. Attached Figure Description

[0019] Figure 1 This is a three-dimensional structural diagram of the entire invention; Figure 2 This is a schematic diagram of the air inlet structure of the present invention; Figure 3This is an exploded structural diagram of the sealing unit of the present invention; Figure 4 This is a schematic diagram of the overall structure of the test cavity after cross-section. Figure 5 This is a schematic diagram of the overall front cross-sectional structure of the present invention; Figure 6 For the present invention Figure 5 Enlarged structural diagram at point A in the middle; Figure 7 This is a three-dimensional structural diagram of the extrusion plate of the present invention; Figure 8 This is a schematic diagram of the overall structure of the sealing ring of the present invention.

[0020] In the picture: 11. Body; 12. Test chamber; 13. Specimen; 14. Air inlet; 15. End cap; 16. Extrusion column; 2. Sealing unit; 27. Vent hole; 28. Sealing part; 29. ​​Sealing ring; 20. Sliding surface; 20. Bending surface; 21. Abutment surface; 22. Extrusion chamber; 23. Extrusion groove; 24. Extrusion groove; 25. Bending surface; 26. Abutment surface; 27. Extrusion chamber; 28. Extrusion plate; 29. ​​Push groove; 20. Triangular groove. Detailed Implementation

[0021] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0022] Reference Figures 1-8This invention provides a gas permeation testing device for containment concrete under gas-thermal coupling, comprising a body 1, several test chambers 11 bolted to the top of the body 1, a specimen 12 placed in the test chambers 11, an air inlet 13 on the top of the body 1, an end cap 14 bolted to the top of the test chambers 11, the top of the end cap 14 connected to the remaining test devices via an air valve (existing technology), a compression column 15 fixedly connected to the bottom of the end cap 14, the compression column 15 abutting against the specimen 12 to provide compression force on the specimen 12, and a heating module installed in the body 1. It also includes at least one sealing unit 2 disposed inside the test chambers 11; the sealing unit 2 includes a vent 21 opened at the bottom of the inner cavity of the test chamber 11, fixedly connected to... The support plate at the bottom of the vent 21, the specimen 12 abuts against the support plate, the outer edge and the middle of the support plate are through-holes, the sealing part 22 is set at the top of the vent 21, the sealing ring 23 abuts against the sealing part 22, the sealing ring 23 is triangular in shape, the sliding surface 24 is opened at the top of the sealing ring 23, the sliding surface 24 is slidably connected to the top of the sealing part 22, the curved surface 25 is opened near the center of the sealing ring 23, the abutting surface 26 is opened at the bottom of the sealing ring 23 and smoothly connected to the curved surface 25, the extrusion cavity 27 is opened inside the sealing ring 23, and the extrusion plate 28 is embedded inside the extrusion cavity 27; the sealing ring 23 is made of elastic rubber; the sealing part 22 is an annular hole with the spacing gradually decreasing in the vertical direction and connected to the vent 21.

[0023] Specifically, during the test, a specimen 12 of a predetermined size needs to be prepared in advance. Specimen 12 can be obtained through core drilling or mold forming. Before being placed in the test chamber, its end face and sidewalls need to be ground to ensure flatness and prevent air leakage. Then, it is placed in a 60-degree Celsius oven to dry to constant weight, eliminating the influence of moisture on the gaps (if testing permeability in a humid state, the natural moisture content must be retained). Afterward, the cylindrical concrete is placed into the test chamber 11, and the end cap 14 is fixed to the test chamber 11 for air tightness testing (gas at a certain pressure is injected and maintained for a period of time; by observing the pressure sensor reading, if the pressure drop is less than 5%, it is considered to be a qualified seal; otherwise, it needs to be resealed or the specimen 12 needs to be replaced). After the air tightness test is qualified, the heating module is turned on, and high-pressure gas (water vapor or helium, etc.) is introduced to test its gas permeability under the action of gas-thermal coupling (the above test is existing technology and will not be described in detail). Maintaining a tight seal between the specimen 12 and the test chamber 11 during the test is crucial for accurate test results. When the specimen 12 is placed into the test chamber 11, the sidewall of the specimen 12 compresses the sealing ring 23. Since the sealing ring 23 is made of rubber, the end compressed by the specimen 12 bends under the friction of the specimen 12, causing the entire ring to move and rotate towards the specimen 12. This pulls the seal towards the sealing part 22. Because the sealing ring 23 is triangular and the distance between the sealing grooves gradually decreases in the vertical direction, the sealing ring 23 tightly compresses the sealing part 22. It does not detach from the sealing part 22; instead, it compresses the sealing part 22 even more tightly, thereby improving the sealing effect of the sealing ring 23 on the sidewall of the specimen 12. Unlike traditional methods that apply preload through bolts or hydraulic devices, this method requires no other equipment, resulting in a simple structure. When the sealing ring 23 is pulled, the internal compression plate 28 also rotates. Since one end of the sealing ring 23 is already compressed and bent, and as the specimen 12 continues to move downward, the sealing ring 23 will continue to rotate around its bottom under the continuous action of friction, causing the compression plate 28 to be compressed and rotated synchronously. Its top will abut against the bend of the sliding surface 24. The more the sealing ring 23 is pulled down and rotated, the greater the pressure exerted by the compression plate 28 on the bend of the sliding surface 24 at one end of the sealing ring 23, resulting in a better sealing effect.

[0024] By utilizing the insertion of the specimen 12 into the test chamber 11, the elastic rubber sealing ring 23 is automatically bent and rotated due to the compression of the side wall, forming a seal without external pre-tightening force. The triangular structure of the sealing ring 23 cooperates with the tapered annular hole of the sealing part 22 (the vertical spacing gradually decreases), forming a "wedge effect." That is, the deeper the specimen 12 is inserted, the tighter the sealing ring 23 is compressed, achieving a dynamic self-tightening seal, which is especially suitable for high-pressure scenarios. It also has a multi-stage sealing effect. When the sealing ring 23 is compressed by the specimen 12, its sliding surface 24 on one side is in contact with the inner wall of the test chamber 11 and the specimen 12, respectively, blocking the radial leakage path of gas along the side wall of the specimen 12, forming a first-stage seal. When one end of the sealing ring 23 is rubbed and pulled... During rotation, the sliding surface 24 rubs tightly against the top of the sealing part 22, forming an axial pressure gradient using the tapered structure, further compressing the sealing ring 23, reducing axial gas permeation, and forming a secondary seal. The extrusion plate 28, rotating with the sealing ring 23, extrudes its internal extrusion cavity 27, with its top abutting against the curved part of the sliding surface 24. Through a "lever effect," the extrusion force is amplified, forming a composite seal of elastic deformation and mechanical extrusion, creating a tertiary seal. This effectively enhances the sealing performance during the test and is of great significance for improving the accuracy of the test results. Furthermore, it exhibits multi-field adaptability. In gas-thermal coupling environments (such as high temperatures causing the specimen 12 to expand), the elastic deformation of the sealing ring 23 can adaptively compensate for dimensional changes, avoiding gaps caused by thermal expansion and contraction in traditional rigid seals.

[0025] It should be noted that the sidewalls of the concrete specimen 12 used for the containment vessel in nuclear power engineering must meet high-density standards, and large voids are not allowed. During construction, through strict mix design, vibration processes, and quality testing, the porosity can be controlled within the minimum allowable range (e.g., total porosity ≤ 3%, primarily consisting of harmless closed pores). Any voids exceeding the standard must be eliminated through design review or defect treatment (e.g., pressure grouting) to ensure the integrity of the containment vessel and its nuclear safety functions. All existing voids can be covered by the sliding surface 24, preventing air leakage from larger voids after sealing by the sealing ring 23. To further ensure airtightness, multiple sealing units 2 can be installed, with the vents 21 in these sealing units interconnected.

[0026] Reference Figure 6 The curved surface 25 and the abutting surface 26 together form an S-shape, and the abutting surface 26 abuts against the bottom of the sealing part 22.

[0027] Specifically, the abutting surface 26 is used to abut the sealing ring 23 when it is pulled and rotated. The curved surface 25 is designed to facilitate the bending of the sealing ring 23. It forms an S-shape, which makes it easy for one end of the sealing ring 23 to bend. The abutting surface 26 plays abutting role, so that the sealing ring 23 will rotate around the abutting surface 26 when it is pulled, so that the sliding surface 24 and the abutting surface 26 respectively squeeze and seal the sealing part 22.

[0028] Reference Figure 6 The sealing unit 2 also includes a push groove 29 opened on the side of the sealing ring 23 facing the vent 21, and the push groove 29 is a concave arc shape.

[0029] Specifically, since the vent 21, sealing part 22 and air inlet 13 are connected, high-pressure gas can squeeze the push groove 29. The recessed design of the push groove 29 causes the sealing ring 23 to be pushed and squeezed towards the specimen 12. That is, after the specimen 12 is placed, when high-pressure gas passes through, the sealing ring 23 will still be pushed and squeezed by the high-pressure gas to further enhance its sealing performance, forming a self-sealing effect where the higher the pressure, the tighter the seal. It can also dynamically compensate for the sealing gap. When the gap between the specimen 12 and the test chamber 11 changes due to thermal expansion (such as concrete expansion in high-temperature tests) or processing errors, the air pressure in the push groove 29 will automatically adjust the deformation of the sealing ring 23 to fill the gap.

[0030] Reference Figure 6 The extrusion chamber 27 includes an extrusion groove 271 formed inside the sealing ring 23. The extrusion groove 271 is an arc shape that bends toward the center of the test chamber 11. A protrusion 272 is installed on one side of the extrusion groove 271. One end of the extrusion plate 28 matches the extrusion groove 271. The extrusion plate 28 is made of rigid material. The top of the extrusion plate 28 is curved upward in the opposite direction to the bending direction of the extrusion groove 271.

[0031] Specifically, the sealing ring 23 is first pulled and moved. When it can no longer move, it rotates around the abutment surface 26 as the base point. At this time, the end of the sealing ring 23 is bent, causing the extrusion plate 28 in the extrusion groove 271 to rotate. Under the abutment of the protrusion 272, it extrudes the bent part of the sliding surface 24. The upward tilt of the top of the extrusion plate 28 facilitates the extrusion of the bent part of the sliding surface 24, thereby improving the extrusion sealing effect.

[0032] Reference Figure 6 In the initial state, the sealing ring 23 and the extrusion plate 28 are always inside the sealing part 22 in the vertical direction.

[0033] Specifically, this arrangement avoids interference between the specimen 12 and the extrusion plate 28 when the specimen 12 moves downward.

[0034] Reference Figure 6 Triangular grooves 3 are evenly provided on one side of the sliding surface 24.

[0035] Specifically, the triangular groove 3 is used to increase the friction between the side wall of the specimen 12 and the sealing ring 23. When the rubber sealing ring 23 is compressed, the tip of the triangular groove 3 will be embedded into the micropores on the surface of the concrete specimen 12, forming a "mortise and tenon" engagement, which effectively prevents the sealing ring 23 from sliding along the axial direction of the specimen 12.

[0036] Reference Figure 6 In the initial state, the sealing ring 23 extends out of the inner wall of the test chamber 11 on one side near the center of the test chamber 11.

[0037] Specifically, this ensures that when the specimen 12 moves downward, it fully contacts the sliding surface 24 of the sealing ring 23, thereby causing the sliding surface 24 of the sealing ring 23 to bend.

[0038] The working principle of this invention is as follows: Before testing, a smoothed concrete specimen 12 is inserted into the test chamber 11. Its sidewalls compress the initially convex triangular elastic rubber sealing ring 23. Under the action of friction, the sealing ring 23 bends and rotates, moving downwards along the sealing part 22 (gradually narrowing annular hole). Utilizing the "wedge effect," a dynamic self-tightening seal is formed. The deeper the specimen 12 is inserted, the tighter the sealing ring 23 is compressed due to the gradually narrowing hole diameter, thus blocking radial leakage without external pre-tightening force. During testing, high-pressure gas enters the concave arc-shaped pushing groove 29 of the sealing ring 23 through the vent 21. The air pressure drives the sealing ring 23 to further compress towards the specimen 12, forming a self-sealing effect of "the higher the pressure, the tighter the seal," dynamically compensating for gaps caused by thermal expansion or processing errors. Simultaneously, the rotation of the sealing ring 23 drives the internal rigid extrusion plate 28, amplifying the extrusion force through a "lever effect." Combined with the axial pressure gradient formed by the tapered structure of the sealing part 22 and the mechanical extrusion of the sliding surface 24 by the extrusion plate 28, a three-level composite sealing mechanism of elastic deformation, air pressure drive, and mechanical reinforcement is constructed. In addition, the S-shaped curved surface 25 and the abutment surface 26 guide the sealing ring 23 to rotate uniformly towards the center of the sealing ring 23. The triangular groove 3 is embedded in the micropores of the specimen 12 to enhance friction. The elastic material adapts to multiple loads (such as high-temperature expansion), ensuring reliable sealing during the test and providing support for accurate testing of the permeability performance of containment concrete.

[0039] Example 2, a second embodiment of the present invention, provides a method for testing the gas permeability of containment concrete under gas-thermal coupling, comprising the following steps: S1. Open the end cap 14, put the pre-prepared cylindrical specimen 12 into the test chamber 11, and tighten the end cap 14 to the top of the test chamber 11 with bolts.

[0040] S2. During the process of the cylindrical specimen 12 sliding into the test chamber 11, the side wall of the bottom of the specimen 12 slides down and enters the sealing ring 23, squeezing one side of the sealing ring 23, causing the sealing ring 23 to bend downward along the surface of the specimen 12, and pressing down the extrusion plate 28 to bend towards the specimen 12, so that the end of the extrusion plate 28 squeezes the bending part of the sliding surface 24. The greater the downward rotation of the entire sealing ring 23, the greater the extrusion force of the extrusion plate 28 on the bending part of the sliding surface 24.

[0041] S3. After the specimen 12 is in place, open the machine body 1 for testing. High-pressure gas is introduced into the bottom of the specimen 12 through the air inlet 13, and the heating module is started simultaneously. Since the extrusion column 15 extrudes the top of the specimen 12, the gas permeability of the specimen 12 under the action of gas-thermal coupling is tested.

[0042] S4. When high-pressure gas is introduced, the high-pressure gas compresses the concave push groove 29 through the vent 21. The higher the gas pressure, the better the compression sealing effect.

[0043] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A gas permeation testing device for containment concrete under gas-thermal coupling, comprising a body, a plurality of test chambers disposed on the top of the body, a specimen disposed within the test chambers, an air inlet disposed on the top of the body, an end cap disposed on the top of the test chambers, an extrusion column disposed at the bottom of the end cap, the extrusion column abutting against the specimen, and a heating module disposed within the body, characterized in that, It also includes at least one sealing unit installed inside the test chamber; The sealing unit includes a vent hole at the bottom of the test chamber, a support plate at the bottom of the vent hole, a specimen placed on the support plate, the outer edge and middle of the support plate being through-hole, a sealing part at the top of the vent hole, a sealing ring at the sealing part, the sealing ring being triangular in shape, a sliding surface at the top of the sealing ring being slidably connected to the top of the sealing part, a curved surface at the center of the sealing ring, an abutment surface at the bottom of the sealing ring being smoothly connected to the curved surface, a compression chamber inside the sealing ring, and a compression plate inside the compression chamber. The sealing ring is made of elastic rubber. The sealing part is an annular hole with a gradually decreasing spacing in the vertical direction and connected to the vent.

2. The gas permeation testing device for containment concrete under gas-thermal coupling as described in claim 1, characterized in that, The curved surface and the abutting surface together form an S-shape, and the abutting surface abuts against the bottom of the sealing part.

3. The gas permeation testing device for containment concrete under gas-thermal coupling as described in claim 1, characterized in that, The sealing unit also includes a push groove formed on the side of the sealing ring facing the vent, and the push groove is in the shape of a concave arc.

4. The gas permeation testing device for containment concrete under gas-thermal coupling according to claim 1, characterized in that, The extrusion chamber includes an extrusion groove inside the sealing ring. The extrusion groove is an arc shape that bends toward the center of the test chamber. A protrusion is provided on one side of the extrusion groove. One end of the extrusion plate matches the extrusion groove. The top of the extrusion plate is curved upward in the opposite direction to the bending direction of the extrusion groove.

5. The gas permeability testing device for containment concrete under gas-thermal coupling according to claim 1, characterized in that, In the initial state, the extrusion plate is always inside the sealing part in the vertical direction.

6. The gas permeation testing device for containment concrete under gas-thermal coupling according to claim 1, characterized in that, The sliding surface has triangular grooves evenly distributed on one side.

7. The gas permeation testing device for containment concrete under gas-thermal coupling according to claim 6, characterized in that, In the initial state, the side of the sealing ring closest to the center of the test chamber extends out of the inner wall of the test chamber.

8. A method for testing the gas permeability of containment concrete under gas-thermal coupling, comprising the gas permeability testing apparatus for containment concrete under gas-thermal coupling as described in any one of claims 1-7, characterized in that, Includes the following steps: Open the end cap, place the pre-prepared cylindrical specimen into the test chamber, and tighten the end cap to the top of the test chamber with bolts; As the cylindrical specimen slides into the test chamber, the side wall at the bottom of the specimen slides down and enters the sealing ring, squeezing one side of the sealing ring. This causes the sealing ring to bend downwards along the surface of the specimen, and the pressing plate is pressed down to bend towards one side of the specimen. This causes the end of the pressing plate to press against the bent part of the sliding surface. The greater the downward rotation of the entire sealing ring, the greater the pressing force of the pressing plate on the bent part of the sliding surface. After the specimen is in place, the machine body is opened for testing. High-pressure gas is introduced into the bottom of the specimen through the air inlet, and the heating module is started simultaneously. The extrusion column extrudes the top of the specimen to test the gas permeability of the specimen under the action of gas-thermal coupling.

9. The method for testing gas permeability in containment concrete under gas-thermal coupling according to claim 8, characterized in that, When high-pressure gas is introduced, the high-pressure gas compresses the concave pushing groove through the vent.

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