Test device for the effect of containment bolts on the tearing performance of steel lining

Abstract

The present invention discloses a testing device for the influence of containment bolts on the tearing performance of steel lining, which comprises: a steel lining specimen, including a steel lining plate, bolts welded on the steel lining plate, and concrete poured between the steel lining plates; a preloading device, acting on both ends of the steel lining specimen, for applying a pre-tensioning load to the steel lining specimen; and a loading device, for applying a load to the steel lining specimen after applying the pre-tensioning load to the steel lining specimen. Compared with the prior art, the testing device for the influence of containment bolts on the tearing performance of steel lining of the present invention can tension the two ends of the steel lining plate through the preloading device to achieve different preloads, and when the concrete keeps the force on the steel lining unchanged, the loading device provides a load to the bolts through the concrete, so that the bolts generate shear force on the steel lining, so that the influence of the bolts on the tearing mechanism of the steel lining under different preload conditions can be obtained.

Description

Technical Field

[0001] The invention belongs to the technical field of nuclear power, and more specifically, relates to a testing device for the influence of containment bolts on the tearing performance of a steel lining. Background Art

[0002] In recent years, as my country's nuclear power construction has entered a period of rapid development, nuclear power plants have gradually developed from coastal areas to inland areas, and the safety of nuclear power plants must be given high attention. As the last barrier to nuclear safety-related measures, whether the containment can fully cope with high-energy loads (high temperature, high pressure and high humidity) under severe accident conditions, and whether it can ensure that no radioactive material leaks under high-energy loads or control the leak to a level with little impact on the environment, has become the performance that people are most concerned about.

[0003] The steel lining of the containment is generally anchored in the concrete wall by bolts and angle steels. The steel lining is anchored to the containment wall in different ways at the standard section of the containment, equipment and personnel gates, and penetrations. Under the action of severe accident loads beyond the design basis, the interaction between the steel lining and the concrete, coupled with the influence of the anchoring system on the steel lining, leads to a very complex stress state of the steel lining. The steel lining may be torn at a lower stress level due to the influence of stress concentration. If the containment structure cannot withstand the high-energy load under the beyond-design basis accident and causes the steel lining to tear, the containment's sealing will fail, and radioactive material leakage is bound to occur. The sealing performance of the steel lining directly determines whether the safety barrier of the nuclear power unit is complete, and the tearing characteristics of the steel lining are directly related to the sealing performance. Therefore, it is particularly important to study the tearing mechanism of the steel lining under severe accident loads.

[0004] The deformation difference between the steel lining and concrete of the containment under load will cause the concrete to transfer a part of the shear force to the steel lining through the studs. This part of the shear force will cause additional strain in the connection between the studs and the steel lining. At present, the design of the studs and steel lining of the containment of nuclear power plants is mainly based on engineering experience and corresponding calculation theories, and the differences in material cross-sectional dimensions and material properties are used to ensure that the studs are damaged before the steel lining. However, this design method only considers the case where the steel lining itself is not preloaded. Under severe accident loads, the steel lining itself will bear a large load. When the stress on the steel lining reaches its yield strength, the additional shear force brought by the studs will cause a large plastic deformation in the local part of the steel lining, which may cause the local part of the steel lining to tear first, resulting in its sealing failure.

[0005] At present, there is still a lack of relevant research, and the influence of the shear force added by the studs on the tearing mechanism of the steel lining under the action of preload is still unclear. Therefore, systematic experimental and theoretical research is needed to provide a reference for the design of the containment steel lining. In view of the particularity of the containment structure of nuclear power plants, it is urgent to design a test device for the influence of containment studs on the tearing performance of the steel lining to study the above problems, so as to obtain reliable test data and provide a reference for the design of the containment steel lining and studs of nuclear power plants. Summary of the invention

[0006] The object of the present invention is to overcome at least one defect in the prior art and provide a testing device for the effect of containment bolts on the tearing performance of a steel liner.

[0007] In order to achieve the above-mentioned object of the invention, the present invention provides a testing device for the effect of containment bolts on the tearing performance of steel lining, which comprises:

[0008] A steel lining test piece, wherein the steel lining test piece comprises a steel lining plate, studs welded to the steel lining plate according to the containment welding requirements of a nuclear power plant, and concrete poured between the steel lining plates;

[0009] a preloading device, acting on both ends of the steel lining specimen, for applying a pre-tensioning load to the steel lining specimen; and

[0010] A loading device is used to apply a load to the steel lining specimen after applying a pre-tensioning load to the steel lining specimen.

[0011] According to an embodiment of the testing device for the effect of containment bolts on the tearing performance of the steel liner of the present invention, the steel lining plate is arranged on both sides of the concrete, and the bolts are welded in the middle of the steel lining plate.

[0012] According to one embodiment of the testing device for the influence of containment bolts on the tearing performance of the steel lining of the present invention, both ends of the steel lining specimen are thickened and fixedly connected with a pair of clamps, the thickened ends of the steel lining specimen are respectively provided with through holes, the clamps are provided with threaded holes, and threaded steel bars are respectively installed through the through holes and the threaded holes.

[0013] According to one embodiment of the testing device for the influence of containment bolts on the tearing performance of the steel lining of the present invention, the clamps are respectively fixedly connected with tie rods, the tie rods are respectively connected with load sensors through threaded connections, the load sensors are respectively fixedly connected with first jacks, and the pair of the first jacks applies a pre-tensioned load to the steel lining specimen.

[0014] According to one embodiment of the testing device for the influence of containment bolts on the tearing performance of the steel lining of the present invention, the fixture is provided with a hemispherical mounting hole, the bottom end of the pull rod is configured to be a hemispherical shape adapted to the hemispherical mounting hole, and the hemispherical bottom end of the pull rod can rotate freely in the hemispherical mounting hole.

[0015] According to an embodiment of the testing device for the effect of containment bolts on the tearing performance of a steel liner of the present invention, displacement sensors are symmetrically provided on both sides of the fixture.

[0016] According to an embodiment of the testing device for the effect of containment bolts on the tearing performance of a steel liner of the present invention, the testing device further comprises a support for supporting the steel liner specimen and the fixture.

[0017] According to one embodiment of the testing device for the influence of containment bolts on the tearing performance of the steel lining of the present invention, a load transfer steel plate is provided in the middle of the steel lining specimen, both ends of the load transfer steel plate are connected to the second jacks through load sensors respectively, and the pair of second jacks apply load to the steel lining specimen through the load transfer steel plate.

[0018] According to an embodiment of the testing device for the effect of containment bolts on the tearing performance of a steel liner of the present invention, displacement sensors are symmetrically provided on both sides of the load transfer steel plate.

[0019] According to one embodiment of the testing device for the effect of containment bolts on the tearing performance of the steel lining of the present invention, the testing device further includes a reaction steel frame, the preloading device is fixedly mounted on two opposite sides of the reaction steel frame through a reaction steel seat, and the loading device is fixedly mounted on one side of the reaction steel frame.

[0020] In addition, the present invention also provides a method for preparing a steel lining specimen for testing the effect of containment bolts on the tearing performance of a steel lining, which comprises the following steps:

[0021] S1: providing a pair of steel lining plates, and welding the studs to the middle of the pair of steel lining plates respectively according to the welding process requirements of the nuclear power plant containment steel lining plates and studs to obtain a welded part;

[0022] S2: fixing the mold in the middle of the welded part obtained in step S1, pouring concrete and fully vibrating it with a vibrating rod, so that the steel lining plate and the studs are poured together to obtain a cast part; and

[0023] S3: After wet-water curing of the cast member obtained in step S2, a steel lining specimen for testing the influence of containment bolts on the tearing performance of the steel lining is obtained.

[0024] According to an embodiment of the method for preparing a steel lining specimen for testing the effect of containment bolts on the tearing performance of a steel lining, after completing step S1 welding, nondestructive testing is performed on the weld between the steel lining plate and the bolts.

[0025] According to an embodiment of the method for preparing a steel lining specimen for testing the influence of containment bolts on the tearing performance of a steel lining of the present invention, in step S1, both ends of the steel lining plate are thickened and fixedly connected with a pair of clamps, the thickened ends are respectively provided with through holes, the clamps are provided with threaded holes, and threaded steel bars are respectively installed through the through holes and the threaded holes.

[0026] In addition, the present invention also discloses a steel lining specimen for testing the influence of containment bolts on the tearing performance of the steel lining, which is prepared according to the preparation method of the steel lining specimen for testing the influence of containment bolts on the tearing performance of the steel lining of the present invention.

[0027] Compared with the prior art, the test device for the influence of containment bolts on the tearing performance of the steel lining of the present invention can tension the two ends of the steel lining plate to achieve different preloads through a preloading device. When the concrete keeps the stress on the steel lining unchanged, the loading device provides load to the bolts through the concrete, so that the bolts produce shear force on the steel lining. Therefore, the influence of the bolts on the tearing mechanism of the steel lining under different preload conditions can be obtained, providing a reliable test basis for the design and sealing evaluation of the containment steel lining of a nuclear power plant. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The following is a detailed description of the testing device for the effect of containment bolts on the tearing performance of the steel liner and its technical effects in conjunction with the accompanying drawings and specific embodiments, wherein:

[0029] Figure 1 It is a schematic diagram of the structure of a testing device for the influence of containment bolts on the tearing performance of a steel lining according to the present invention.

[0030] Figure 2 It is along Figure 1 Schematic diagram of the cross-section along line AA.

[0031] Figure 3 It is a front view of a steel lining test piece in a testing device for the influence of containment bolts on the tearing performance of a steel lining according to the present invention.

[0032] Figure 4 It is a cross-sectional schematic diagram of a steel lining test piece in a testing device for the influence of containment bolts on the tearing performance of a steel lining according to the present invention.

[0033] Figure 5 and Figure 6 The front view and side view of the fixture in the test device for the influence of containment bolts on the tearing performance of the steel liner of the present invention.

[0034] Figure 7 It is a structural schematic diagram of a pull rod in a test device for the influence of containment bolts on the tearing performance of a steel lining according to the present invention.

[0035] In the figure:

[0036] 1--Steel lining plate; 2--Studs; 3--Concrete; 4--Clamp; 5--Tie rod; 6--Threaded steel bar; 7--Load sensor; 8--First jack; 9--Displacement sensor; 10--Second jack; 11--Reaction steel seat; 12--Load transfer steel plate; 13--Roller support; 14--Reaction steel frame; 15--Nuts and washers. DETAILED DESCRIPTION

[0037] In order to make the invention purpose, technical solution and technical effect of the present invention clearer, the present invention is further described in detail below in conjunction with the accompanying drawings and specific implementation methods. It should be understood that the specific implementation methods described in this specification are only for explaining the present invention, not for limiting the present invention.

[0038] Please refer to Figure 1 and Figure 2 As shown, the present invention provides a testing device for the effect of containment bolts on the tearing performance of steel lining, which comprises:

[0039] A steel lining test piece, the steel lining test piece comprises a steel lining plate 1, studs 2 welded to the steel lining plate 1 according to the containment welding requirements of a nuclear power plant, and concrete poured between the steel lining plates 1;

[0040] A preloading device, acting on both ends of the steel lining specimen, for applying a pre-tensioning load to the steel lining specimen; and

[0041] The loading device is used to apply a load to the steel lining specimen after a pre-tensioning load is applied to the steel lining specimen.

[0042] Please refer to Figure 3 and 4 As shown in the figure, the steel lining specimen is made as follows:

[0043] First, two steel lining plates 1 with arcs are processed and manufactured, and both ends of the steel lining plate 1 are thickened. The steel lining plate 1 is P265GH steel used in BS EN 10028-2:2017 "European Standard for Steel Plates for Pressure Vessels", with a thickness of 6 mm and a 20 mm thickened area at the end; then, four threaded holes are symmetrically arranged at the thickened end of the steel lining plate 1; according to the welding process and requirements of the steel lining 1 and the studs 2 of the nuclear power plant containment, the studs 2 are respectively welded to the middle of the two steel lining plates 1, and each steel lining plate 1 has two studs 2, which are ML15AL / Q235B studs with a diameter of 8 mm, a length of 80 mm, and a horizontal welding spacing of 150 mm. After welding, non-destructive testing is performed on the weld; a wooden mold is fixed in the middle of the steel lining specimen, and concrete 3 is poured to make the steel lining plate 1 and the studs 2 are poured together, the concrete strength grade is C50, and the mix ratio is cement: admixture: medium sand: small crushed stone: large crushed stone: water: water reducing agent = 1: 0.137: 1.37: 0.798: 1.862: 0.319: 0.016, wherein the cement is ordinary Portland cement with a strength grade of 52.5, the admixture is S95 slag powder, the small crushed stone refers to the stone with a particle size of 5-10mm, the large crushed stone refers to the stone with a particle size of 10-20mm, and the water reducing agent is PC-J100 polyhydroxy acid high-efficiency water reducing agent; when pouring concrete 3, vibrate it fully with a vibrating rod to ensure that the concrete 3 is dense. After the specimen is poured, the surface is covered with plastic wrap and wet-water cured for 28 days to finally form the specimen. In the prepared steel lining specimen, the steel lining plate 1 is arranged on both sides of the concrete 3, and the stud 2 is welded to the middle of the steel lining plate 1.

[0044] Please refer to Figures 1 to 4 As shown, the two ends of the steel lining specimen are thickened and fixedly connected with a pair of clamps 4. The two ends of the thickened steel lining specimen are respectively provided with through holes, and the clamp 4 is provided with threaded holes. Threaded steel bars 6 are respectively installed through the through holes and the threaded holes. The threaded steel bars 6 are PSB785 type prestressed threaded steel bars, and the diameter of the steel bars should be greater than the thickness of the thickened area of ​​the steel lining plate 1. Displacement sensors 9 are symmetrically arranged on both sides of the clamp 4. The clamp 4 is respectively fixedly connected with pull rods 5. The pull rods 5 are respectively connected with load sensors 7 through threaded connections. The load sensors 7 are respectively fixedly connected with first jacks 8 (200t hydraulic jacks). The pair of first jacks 8 apply pre-tension loads to the steel lining specimen.

[0045] According to one embodiment of the present invention, the material of the clamp 4 is Q235B steel, including a tie rod connecting plate (not marked) and a specimen connecting plate (not marked), a concave hemispherical mounting hole is reserved in the tie rod connecting plate for connecting the tie rod 5, and four threaded holes are reserved on both sides of the specimen connecting plate for connecting the specimen; the tie rod connecting plate and the specimen connecting plate are welded together to form the clamp 4.

[0046] Please refer to Figure 5 and 6 As shown, the fixture 4 is provided with a hemispherical mounting hole. Figure 7 As shown, the pull rod 5 is made of Q235B steel, and the bottom end of the pull rod 5 is set to a hemispherical shape that matches the hemispherical mounting hole. The hemispherical bottom end of the pull rod 5 can rotate freely in the hemispherical mounting hole, and the top end of the pull rod 5 is cylindrical and has threads.

[0047] Please continue to refer to Figure 1 As shown, a load transfer steel plate 12 is provided in the middle of the steel lining specimen, and both ends of the load transfer steel plate 12 are connected to the second jack 10 (50t hydraulic jack) through load sensors 7 respectively. A pair of second jacks 10 applies load to the steel lining specimen through the load transfer steel plate 12, and displacement sensors 9 are symmetrically provided on both sides of the load transfer steel plate 12.

[0048] Please continue to refer to Figure 1 As shown, the testing device for the influence of the containment bolts on the tearing performance of the steel liner of the present invention also includes a reaction steel frame 14, a pair of first jacks 8 are fixedly installed on two opposite sides of the reaction steel frame 14 through a reaction steel seat 11, and a second jack 10 is fixedly installed on one side of the reaction steel frame 14. The first jack 8 and the second jack 10 apply forces to the steel liner in the same direction.

[0049] The following describes in detail the installation process of the test device for the effect of containment bolts on the tearing performance of the steel liner according to the present invention in conjunction with the accompanying drawings:

[0050] Please refer to Figure 1 As shown, four steel plates are connected by bolts and washers 15 to form a reaction steel frame 14, and the reaction steel seat 11 is placed on one side of the reaction steel frame 14; four threaded steel bars 6 are inserted into the through holes reserved on the steel lining plate 1 at both ends of the steel lining specimen, and the position of the steel lining plate 1 on the threaded steel bars 6 is fixed by nuts and washers 15; the tie rod 5 is passed through the hole reserved in the tie rod connecting plate on the clamp 4, and then the tie rod connecting plate and the specimen connecting plate are welded to form the clamp 4; the threaded steel bars 6 at the end of the specimen are inserted into the threaded holes reserved on the clamp 4, and then the clamp 4 and the specimen are fixed by nuts and washers 15, and when fixing, it is strictly ensured that the clamps 4 at the upper and lower ends of the specimen are on the same horizontal line;

[0051] Connect the load sensor 7 to the threaded hole reserved at the bottom of the load sensor 7 through the thread on the pull rod 5; fix the top of the load sensor 7 to the top of the 200t hydraulic jack 8, and fix the bottom of the 200t hydraulic jack 8 to the reaction steel frame 14; place the roller support 13 on the ground to support the specimen and the fixture 4 (please refer to Figure 2As shown); a load transfer steel plate 12 is placed in the middle of the specimen, and a load sensor 7 and a 50t hydraulic jack 10 are connected to both ends of the load transfer steel plate 12. The bottom of the 50t hydraulic jack 10 is connected to the reaction steel seat 11; the displacement sensors 9 are symmetrically placed on both sides of the fixture 4 and the two sides of the load transfer steel plate 12 through fixed supports.

[0052] The following describes in detail the test process of the test device for the effect of containment bolts on the tearing performance of the steel liner of the present invention in conjunction with the accompanying drawings:

[0053] After the test device for the effect of containment bolts on the tearing performance of the steel lining is installed, it can be loaded. The reaction steel frame 14 is placed flat on the ground, and the steel lining plate 1 on the test piece is bidirectionally and synchronously stretched by the 200t first jacks 8 at both ends of the reaction steel frame 14 to apply a preload;

[0054] Then, the load is kept constant, and the two 50t hydraulic second jacks 10 are pressurized synchronously. The second jacks 10 are pressed against the load transfer steel plate 12 and drive the load transfer steel plate 12 to move. The displacement direction of the load transfer steel plate 12 is parallel to the tensile direction. After the load transfer steel plate 12 contacts the concrete 3 on the specimen, a thrust is formed on the concrete 3. The thrust causes the concrete 3 to drive the stud 2 to deform, and then the stud 2 applies a shear force to the steel lining plate 1. At this time, the contact mode between the tie rod connecting plate on the fixture 4 and the tie rod hemispherical surface allows the two to rotate flexibly and ensures that the tension is always kept vertical, which can effectively reduce the influence of eccentricity.

[0055] Combined with the above detailed description of the embodiments of the present invention, it can be seen that, compared with the prior art, the test device for the effect of containment bolts on the tearing performance of the steel liner of the present invention has the following advantages:

[0056] Firstly, the preloading device can be used to tension the two ends of the steel lining plate 1 to achieve different preloads. When the concrete 3 keeps the stress on the steel lining unchanged, the loading device provides a load to the stud 2 through the concrete 3, so that the stud 2 generates a shear force on the steel lining. Therefore, the influence of the stud on the tearing mechanism of the steel lining under different preloads can be obtained, which can provide a reliable experimental basis for the design and sealing evaluation of the steel lining of the containment of a nuclear power plant.

[0057] Secondly, in the test device for the influence of the containment bolts on the tearing performance of the steel lining of the present invention, the matching clamp 4 is simple to manufacture, flexible and convenient to use and has good loading stability. By setting a hemispherical contact mode on the contact surface between the clamp 4 and the pull rod, the two can rotate flexibly and ensure that the pulling force always remains horizontal, which can effectively reduce the influence of eccentricity.

[0058] Thirdly, the designed loading device is placed flat on the ground, which can effectively prevent the concrete from falling when the specimen is destroyed, thereby ensuring the safety during the test. Since the test process requires the simultaneous application of parallel and opposite tension and thrust to the specimen, it is difficult to achieve with existing tensile testing machines. The test device designed by the present invention can solve this problem well. The entire designed loading device has a compact structure, reasonable design, safety and reliability. The loading device can be dismantled and reinstalled at any time, which can effectively save space and reduce idle resources, and is suitable for most laboratory conditions.

[0059] According to the above principles, the present invention can also make appropriate changes and modifications to the above embodiments. Therefore, the present invention is not limited to the specific embodiments disclosed and described above, and some modifications and changes to the present invention should also fall within the scope of protection of the claims of the present invention. In addition, although some specific terms are used in this specification, these terms are only for the convenience of description and do not constitute any limitation to the present invention.

Claims

1. A test device for the effect of containment bolts on the tearing performance of steel lining, characterized in that: include: A steel lining test piece, wherein the steel lining test piece comprises a steel lining plate, studs welded to the steel lining plate according to the containment welding requirements of a nuclear power plant, and concrete poured between the steel lining plates; A preloading device, acting on both ends of the steel lining specimen, is used to apply a pre-tensioning load to the steel lining specimen, the preloading device comprising: a reaction steel frame, a pair of first jacks fixedly installed on two opposite sides of the reaction steel frame, a pair of load sensors fixedly connected to the pair of first jacks, a pair of tie rods respectively connected to the pair of load sensors, a pair of clamps respectively fixedly connected to the pair of tie rods, and displacement sensors respectively located on both sides of the pair of clamps, the two ends of the steel lining specimen are respectively fixedly connected to the pair of clamps, and the pair of first jacks apply a pre-tensioning load to the steel lining specimen; as well as A loading device is used to apply a load to the steel lining specimen after applying a pre-tensioning load to the steel lining specimen.

2. The testing device for the effect of containment bolts on the tearing performance of steel lining according to claim 1, characterized in that: The steel lining plates are arranged on both sides of the concrete, and the bolts are welded in the middle of the steel lining plates.

3. The testing device for the effect of containment bolts on the tearing performance of steel lining according to claim 1, characterized in that: Both ends of the steel lining specimen are thickened and fixedly connected to the pair of clamps respectively. Through holes are respectively provided at both ends of the thickened steel lining specimen, and threaded holes are provided on the clamps. Threaded steel bars are respectively installed through the through holes and the threaded holes.

4. The testing device for the effect of containment bolts on the tearing performance of steel lining according to claim 3 is characterized in that: The pull rods are respectively connected to the load sensors through threaded connections.

5. The testing device for the effect of containment bolts on the tearing performance of steel lining according to claim 4, characterized in that: The clamp is provided with a hemispherical mounting hole, the bottom end of the pull rod is configured to be a hemispherical shape adapted to the hemispherical mounting hole, and the hemispherical bottom end of the pull rod can rotate freely in the hemispherical mounting hole.

6. The testing device for the effect of containment bolts on the tearing performance of steel lining according to claim 3, characterized in that: The displacement sensors are symmetrically arranged on both sides of the clamp.

7. The testing device for the effect of containment bolts on the tearing performance of steel lining according to claim 3, characterized in that: Further comprising a support for supporting the steel lining specimen and the fixture.

8. The testing device for the effect of containment bolts on the tearing performance of steel lining according to claim 1, characterized in that: A load transfer steel plate is provided in the middle of the steel lining specimen, and both ends of the load transfer steel plate are connected to a second jack via load sensors respectively, and the second jack applies load to the steel lining specimen via the load transfer steel plate.

9. The testing device for the effect of containment bolts on the tearing performance of steel lining according to claim 8, characterized in that: Displacement sensors are symmetrically arranged on both sides of the load transfer steel plate.

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