A device and method for irradiation compression creep test of metal pipes

Abstract

The present invention provides a metal pipe irradiation compression creep test device and method, which relates to the technical field of the design of metal materials for reactor cores. Aiming at the problem that it is difficult to reproduce the true service environment of metal pipe samples for creep tests, a pressure is applied to the metal pipe through a test box in cooperation with a compression component. After adjusting the thermal resistance, the temperature of the metal pipe specimen is controlled at the temperature level in the operating environment of a commercial pressurized water reactor, and it is placed in a test reactor or a commercial reactor to receive neutron irradiation, achieving synchronous loading of multiple test environments for the metal pipe sample and reproducing the true service environment of the sample to meet the research requirements of creep behavior.

Description

Technical Field

[0001] The present invention relates to the technical field of metal material design for reactor cores, and particularly relates to an irradiation compression creep test device and method for metal tubes. Background Art

[0002] Metal tubes are common structural and functional component forms in reactor cores, mainly playing functions such as support, load bearing, positioning, providing fluid channels or assembly interfaces for solid components, etc., and have an important impact on realizing the design functions of reactors and ensuring the safety and economy of reactors. For example, nuclear fuel assemblies are one of the typical scenarios for the application of metal tubes. In nuclear fuel assemblies, the fuel rod cladding tubes made of metal tubes constitute the first safety barrier for radioactive fission products and have an important impact on ensuring the safety of nuclear power plants. The guide tubes made of metal tubes constitute the basic framework of the fuel assembly, provide axial support for the fuel assembly, and also provide insertion channels for control rod assemblies, and play important roles in ensuring the structural stability of the fuel assembly and the insertability of control rods.

[0003] During the service period of the reactor core, metal tubes will undergo creep under the action of neutron irradiation, high temperature and axial compression loads. Creep will not only cause deformation of the metal tube material, but may also cause damage and fracture, and then lead to the inability of the metal tube to achieve the expected design functions. With the promotion of nuclear power localization work, the creep effect of metal tubes for reactor cores under irradiation, high temperature and stress environments needs to be studied in depth. Especially before the fuel assemblies containing newly designed metal tubes enter the irradiation test of commercial pressurized water reactors, it is necessary to carry out irradiation compression creep tests on metal tubes to verify that the irradiation compression creep performance of the newly designed metal tubes meets the design requirements. To carry out this work, it is first necessary to solve the technical problems of loading in multiple test environments such as neutron irradiation, high temperature and axial compression.

[0004] The currently common method is the independent loading technology for test environments, that is, first constructing high temperature and stress environments outside the reactor to examine metal tube samples, then putting them into the reactor to receive neutron irradiation after meeting certain conditions, and taking them out after reaching the predetermined irradiation dose to complete the test. However, this method cannot restore the true service environment of the samples and cannot effectively explain the equivalence between the test results and the creep behavior of metal tubes during service in the reactor. Summary of the Invention

[0005] The purpose of the present invention is to address the defects existing in the prior art, and provide an irradiation compression creep test device and method for metal tubes. By using a test box to cooperate with a compression component to apply pressure to the metal tube, adjusting the thermal resistance to control the temperature of the metal tube specimen at the temperature level in the operating environment of a commercial pressurized water reactor, and putting it into a test reactor or a commercial reactor to receive neutron irradiation, multiple test environment synchronous loading of the metal tube sample is achieved, and the true service environment of the sample is restored to meet the research requirements of creep behavior.

[0006] The first object of the present invention is to provide a metal pipe irradiation compression creep test device, adopting the following scheme:

[0007] It includes a test box with a test chamber and a compression assembly located in the test chamber. The compression assembly includes a connecting rod and a first pressing ring and a second pressing ring sleeved outside the connecting rod. One end of the connecting rod is provided with an end seat for abutting against the metal pipe. The end seat, the first pressing ring and the second pressing ring are arranged in sequence along the axial direction of the connecting rod. A compression zone for sleeving the metal pipe is formed between the end seat and the first pressing ring. An elastic member is connected between the first pressing ring and the second pressing ring to adjust the pressure in the compression zone by changing the distance between the first pressing ring and the second pressing ring.

[0008] Further, a plurality of test chambers hermetically sealed relative to the outside of the test box are provided in the test box. The test chambers are filled with inert gas, and the test box is equipped with a top cover for blocking the test chambers.

[0009] Further, the test chamber is cylindrical, and the axes of the plurality of test chambers located in the same test box are arranged in parallel.

[0010] Further, adiabatic pads are provided at both ends in the test chamber. Positioning grooves are provided on the adiabatic pads. Both ends of the compression assembly along the axial direction of the test chamber respectively contact the adiabatic pads and cooperate with the positioning grooves.

[0011] Further, the end seat is a stepped shaft. The end seat is coaxially butted with the main body of the connecting rod. The stepped diameter of the end seat connecting one end of the connecting rod is larger than that of the other end. The end seat abuts against one end face of the metal pipe, and the first pressing ring abuts against the other end face of the metal pipe.

[0012] Further, an isothermal body is sleeved outside the connecting rod in the compression zone, and the metal pipe to be tested is sleeved outside the isothermal body.

[0013] Further, positioning bosses are provided on one sides of the first pressing ring and the second pressing ring facing the elastic member. The elastic member is sleeved outside the connecting rod and the positioning bosses, and one end of the elastic member abuts against the first pressing ring and the other end abuts against the second pressing ring.

[0014] Further, a threaded section is provided on the connecting rod, and a pressing nut cooperating with the threaded section is provided on one side of the second pressing ring away from the first pressing ring to push the second pressing ring to change its relative position with the connecting rod.

[0015] The second object of the present invention is to provide a test method using the metal pipe irradiation compression creep test device as described in the first object, including:

[0016] The metal pipe to be tested is sleeved outside the connecting rod corresponding to the compression zone, the first pressing ring, the elastic member and the second pressing ring are installed, and the end of the metal pipe abuts against the end seat and the first pressing ring;

[0017] Adjust the position of the second pressing ring. Apply a load to the metal pipe through the elastic member and the first pressing ring to place the metal pipe under a set axial compression load.

[0018] Place the compression assembly together with the metal pipe into the test chamber. Adjust the gap between the metal pipe and the test chamber to achieve an appropriate gap thermal resistance. Fill the test chamber with an inert gas and seal it.

[0019] Place the test box in a test reactor or a commercial reactor to receive neutron irradiation.

[0020] Furthermore, fill an isothermal body between the connecting rod and the metal pipe in the compression zone to make the temperature distribution of the metal pipe uniform.

[0021] Compared with the prior art, the advantages and positive effects of the present invention are:

[0022] (1) Aiming at the problem that it is difficult to restore the true service environment of metal pipe samples for creep tests at present, apply pressure to the metal pipe through the test box and the compression assembly. After adjusting the thermal resistance, control the temperature of the metal pipe sample at the temperature level under the operating environment of a commercial pressurized water reactor. Place it in a test reactor or a commercial reactor to receive neutron irradiation, achieving synchronous loading of multiple test environments for the metal pipe sample and restoring the true service environment of the sample to meet the research requirements of creep behavior.

[0023] (2) By designing the connecting rod, elastic member, and pressing ring, form a self-pressing structure to provide an axial compression load for the metal pipe sample, so that the compression load of the metal pipe reaches the compression load level under the operating environment of a pressurized water reactor; set the pressing ring sleeved on the connecting rod to be able to stably transfer the pre-tightening force applied to the elastic member by the pressing nut to the metal pipe sample, forming the pressure environment required for the compression creep test, ensuring uniform distribution of the pressure on the end face of the metal pipe, and effectively improving the test accuracy.

[0024] (3) By designing zirconia adiabatic pads and pre-filling helium gas in the sample box, play a heat preservation role for the metal pipe compression creep test assembly, so that the temperature of the metal pipe sample reaches the temperature level of the metal pipe under the operating environment of a pressurized water reactor; by designing copper pipe isothermal bodies in the sample box, the temperature distribution of the metal pipe sample can be made more uniform. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The accompanying drawings forming a part of this invention are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention.

[0026] Figure 1 It is a schematic structural diagram of the metal pipe irradiation compression creep test device in Embodiment 1 or 2 of the present invention.

[0027] Figure 2 It is a schematic end view of the test box in Example 1 or 2 of the present invention.

[0028] Figure 3 It is a cross-sectional schematic diagram of the test box in Example 1 or 2 of the present invention.

[0029] Figure 4 It is a schematic diagram of the structure of the compression assembly in Example 1 or 2 of the present invention.

[0030] In the figure, 1-connecting rod; 2-metal pipe; 3-first clamping ring; 4-compression spring; 5-second clamping ring; 6-nut; 7-isothermal body; 8-upper insulation pad; 9-test box; 10-compression assembly; 11-lower insulation pad; 12-top cover. DETAILED DESCRIPTION

[0031] Example 1

[0032] In a typical embodiment of the present invention, Figures 1 - 4 As shown, a metal pipe irradiation compression creep test device is provided.

[0033] like Figure 1 The metal tube irradiation compression creep test device shown is used to carry out metal tube irradiation compression creep test in a test reactor or a commercial reactor, and can also be used to control the compression load and temperature of the sample in other types of irradiation tests. Through the joint action of the test box 9 and the compression assembly 10, the compression load of the metal tube 2 sample can be controlled at the compression load level borne by the metal tube 2 in the operating environment of the pressurized water reactor, and the temperature of the metal tube 2 sample can be controlled at the temperature level of the metal tube 2 in the operating environment of the pressurized water reactor by adjusting the thermal resistance, meeting the requirements of the compression creep test.

[0034] Combination Figure 1 and Figure 4 The metal pipe irradiation compression creep test device mainly includes a test box 9 and a compression assembly 10. The test box 9 is as follows: Figure 2 and Figure 3 As shown, the compression assembly 10 is Figure 4 shown.

[0035] A test cavity is formed in the test box 9, and the test cavity can accommodate the compression component 10. The metal pipe 2 sample to be tested cooperates with the compression component 10. After the compression component 10 applies prestress to the metal pipe 2, the two are placed in the test cavity together, and the test cavity is sealed and isolated from the outside. The gap between the metal pipe 2 and the test cavity is adjusted to achieve a suitable gap thermal resistance and placed in the required irradiation environment for testing.

[0036] For the structure of the test box 9, combined Figure 2 , Figure 3, there are multiple test cavities sealed relative to the outside of the test box 9 inside the test box 9, and tests on multiple metal pipes 2 can be carried out simultaneously. The test box 9 is made of aluminum alloy material. A counterbore is provided on the test box 9 to form the test cavity. The test cavity is cylindrical, and the axes of multiple test cavities located in the same test box 9 are arranged in parallel.

[0037] In this embodiment, as Figure 3 shown, two test cavities are provided inside the test box 9; as Figure 1 shown, a compression assembly 10 is placed in each test cavity, and the two internal compression assemblies 10 are arranged in parallel.

[0038] The test cavity is filled with inert gas. The test box 9 is equipped with a top cover 12 for plugging the test cavity. In order to make the metal pipes 2 in all test cavities inside the same test box 9 be in the same environmental conditions, the test cavities are connected, and inert gas is simultaneously filled to keep the inert gas evenly distributed.

[0039] The inert gas filled in the test cavity is pre-filled helium gas, which plays a role in heat preservation and preventing oxidation during the compression creep test of the metal pipe 2.

[0040] In addition, when the test cavity accommodates the compression assembly 10 and the metal pipe 2, the heat insulation requirement also needs to be considered. Adiabatic pads are provided at both ends inside the test cavity. Positioning grooves are provided on the adiabatic pads. The two ends of the compression assembly 10 along the axial direction of the test cavity respectively contact the adiabatic pads and cooperate with the positioning grooves.

[0041] In this embodiment, in the posture as Figure 1 shown, the adiabatic pad located above the compression assembly 10 is the upper adiabatic pad 8, and the adiabatic pad located below the compression assembly 10 is the lower adiabatic pad 11. The material of the adiabatic pad is zirconia, and the whole is cylindrical and can be formed by machining; it prevents the temperature from uncontrollably decreasing due to heat transfer of the compression assembly 10 of the metal pipe 2 through the bottom of the test box 9.

[0042] The adiabatic pad cooperates with the test box 9 and the compression assembly 10 of the metal pipe 2, and can play a role in heat insulation and radial positioning for the compression assembly 10 of the metal pipe 2, and can control the gap between the metal pipe 2 specimen and the inner wall of the test cavity.

[0043] Specifically, as Figure 4 shown, the compression assembly 10 can apply an axial pressure to the metal pipe 2 sample. The compression assembly 10 includes a connecting rod 1 and a first pressing ring 3 and a second pressing ring 5 sleeved outside the connecting rod 1. The first pressing ring 3 and the second pressing ring 5 can move axially along the connecting rod 1 to adjust the relative position between the pressing ring and the connecting rod 1. After the metal pipe 2 is installed on the connecting rod 1, the axial pressure of the metal pipe 2 can be changed by adjusting the positions of the first pressing ring 3 and the second pressing ring 5.

[0044] One end of the connecting rod 1 is provided with an end seat for abutting against the metal pipe 2. The end seat can limit the displacement of one end of the metal pipe 2. The end seat, the first pressing ring 3 and the second pressing ring 5 are sequentially distributed along the axial direction of the connecting rod 1. A compression zone for the metal pipe 2 to be sleeved is formed between the end seat and the first pressing ring 3. The first pressing ring 3 abuts against the other end of the metal pipe 2, thereby limiting the displacement of the other end of the metal pipe 2, and further constraining the metal pipe 2 sample in the compression zone to prevent the metal pipe 2 sample from coming out, so as to realize the stable loading of the axial pressure on the metal pipe 2.

[0045] An elastic member is connected between the first pressing ring 3 and the second pressing ring 5 to adjust the pressure in the compression zone by changing the distance between the first pressing ring 3 and the second pressing ring 5. When the distance between the first pressing ring 3 and the second pressing ring 5 becomes smaller, the elastic member is compressed, and the pressure exerted by the elastic member on the metal pipe 2 through the first pressing ring 3 increases; when the distance between the first pressing ring 3 and the second pressing ring 5 becomes larger, the elastic member rebounds, and the pressure exerted by the elastic member on the metal pipe 2 through the first pressing ring 3 decreases. By changing the axial length of the elastic member, the effect of adjusting the pressure applied to the compression zone can be achieved.

[0046] In this embodiment, the connecting rod 1 is a T-shaped structure with an end seat, which can be formed by machining 304 stainless steel, providing structural support for the entire compression assembly 10.

[0047] As Figure 4 shown, the end seat is a stepped shaft. The end seat is coaxially butted with the main body of the connecting rod 1. The stepped diameter of the end seat connecting one end of the connecting rod 1 is larger than that of the other end. The end seat abuts against one end face of the metal pipe 2, and the first pressing ring 3 abuts against the other end face of the metal pipe 2. One end of the elastic member is sleeved outside a partial section of the stepped shaft, and the partial section of the stepped shaft is for the end of the elastic member to abut against.

[0048] Both sides of the first pressing ring 3 and the second pressing ring 5 facing the elastic member are provided with positioning bosses. The elastic member is sleeved outside the connecting rod 1 and the positioning bosses, and one end of the elastic member abuts against the first pressing ring 3 and the other end abuts against the second pressing ring 5.

[0049] A threaded section is provided on the connecting rod 1. A pressing nut 6 matching the threaded section is provided on the side of the second pressing ring 5 away from the first pressing ring 3 to push the second pressing ring 5 to change its relative position with the connecting rod 1; by rotating the pressing nut 6, the relative position of the pressing nut 6 and the connecting rod 1 can be adjusted, thereby constraining the position of the second pressing ring 5, squeezing the second pressing ring 5 to squeeze the elastic member, and further squeezing the metal pipe 2.

[0050] The elastic member is a compression spring 4, and the compression spring 4 is made of GH4169 material; the compression nut 6 is made of 304 stainless steel and is completed by machining. The compression nut 6 is matched with the threaded section of the connecting rod 1 through internal threads to maintain the compression spring 4 in a compressed state.

[0051] An isothermal body 7 is sleeved outside the connecting rod 1 in the compression zone, and the metal pipe specimen 2 to be tested is sleeved outside the isothermal body 7. The isothermal body 7 in this embodiment is a copper pipe, and the copper pipe has a cylindrical structure and is produced by machining with pure copper material. Its main function is to make the temperature distribution of the metal pipe specimen 2 more uniform.

[0052] The compression spring 4, the compression nut 6, the connecting rod 1, the compression ring and the metal pipe specimen 2 form a self-compressing structure, which can provide an axial compression load for the metal pipe specimen 2 to make the compression load of the metal pipe 2 reach the compression load level under the operating environment of a pressurized water reactor.

[0053] By designing zirconia adiabatic pads and pre-filling helium gas in the sample box, it plays a heat preservation role for the metal pipe 2 compression creep test assembly, so that the temperature of the metal pipe specimen 2 reaches the temperature level of the metal pipe 2 under the operating environment of a pressurized water reactor; by designing the copper pipe isothermal body 7 in the sample box, the temperature distribution of the metal pipe specimen 2 can be made more uniform.

[0054] Embodiment 2

[0055] In another typical embodiment of the present invention, as Figures 1 - 4 shown, a test method for a metal pipe irradiation compression creep test device is given.

[0056] Using the metal pipe irradiation compression creep test device as in Embodiment 1, the test method includes:

[0057] The metal pipe 2 to be tested is sleeved outside the corresponding connecting rod 1 in the compression zone, the first compression ring 3, the elastic member and the second compression ring 5 are installed, and the end of the metal pipe 2 abuts against the end seat and the first compression ring 3;

[0058] Adjust the position of the second compression ring 5, and apply a load to the metal pipe 2 through the elastic member and the first compression ring 3 to make the metal pipe 2 under a set axial compression load;

[0059] The compression assembly 10 together with the metal pipe 2 is placed into the test chamber, and the gap between the metal pipe 2 and the test chamber is adjusted to achieve an appropriate gap thermal resistance, and an inert gas is filled and the test chamber is closed;

[0060] The test box 9 is placed in a test reactor or a commercial reactor to receive neutron irradiation.

[0061] In addition, an isothermal body 7 is filled between the connecting rod 1 and the metal pipe 2 in the compression zone to make the temperature distribution of the metal pipe 2 uniform.

[0062] To meet the requirements of the control experiment, a plurality of test cavities can be arranged in the test box 9, and compression assemblies 10 each installed with a metal pipe 2 are respectively arranged in each test cavity.

[0063] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A radiation compression creep test device for metal pipes, characterized in that, it includes a test box with a test chamber and a compression assembly located in the test chamber. The compression assembly includes a connecting rod and a first pressing ring and a second pressing ring sleeved outside the connecting rod. One end of the connecting rod is provided with an end seat for abutting against the metal pipe. The end seat, the first pressing ring and the second pressing ring are arranged in sequence along the axial direction of the connecting rod. A compression zone for sleeving the metal pipe is formed between the end seat and the first pressing ring. An elastic member is connected between the first pressing ring and the second pressing ring to adjust the pressure in the compression zone by changing the distance between the first pressing ring and the second pressing ring.

2. The radiation compression creep test device for metal pipes according to claim 1, characterized in that, a plurality of test chambers hermetically sealed relative to the outside of the test box are provided in the test box. The test chambers are filled with inert gas, and the test box is equipped with a top cover for plugging the test chambers.

3. The radiation compression creep test device for metal pipes according to claim 2, characterized in that, the test chamber is cylindrical, and the axes of the plurality of test chambers located in the same test box are arranged in parallel.

4. The radiation compression creep test device for metal pipes according to claim 1, characterized in that, adiabatic pads are provided at both ends in the test chamber. Positioning grooves are provided on the adiabatic pads. Both ends of the compression assembly along the axial direction of the test chamber respectively contact the adiabatic pads and cooperate with the positioning grooves.

5. The radiation compression creep test device for metal pipes according to claim 1, characterized in that, the end seat is a stepped shaft. The end seat is coaxially butted with the main body of the connecting rod. The stepped diameter of the end seat connecting one end of the connecting rod is larger than that of the other end. The end seat abuts against one end face of the metal pipe, and the first pressing ring abuts against the other end face of the metal pipe.

6. The radiation compression creep test device for metal pipes according to claim 5, characterized in that, an isothermal body is sleeved outside the connecting rod in the compression zone, and the metal pipe to be tested is sleeved outside the isothermal body.

7. The radiation compression creep test device for metal pipes according to claim 1, characterized in that, positioning bosses are provided on one sides of the first pressing ring and the second pressing ring facing the elastic member. The elastic member is sleeved outside the connecting rod and the positioning bosses, and one end of the elastic member abuts against the first pressing ring and the other end abuts against the second pressing ring.

8. The radiation compression creep test device for metal pipes according to claim 7, characterized in that, a threaded section is provided on the connecting rod, and a pressing nut cooperating with the threaded section is provided on one side of the second pressing ring away from the first pressing ring to push the second pressing ring to change its relative position with the connecting rod.

9. A test method for the radiation compression creep test device for metal pipes according to any one of claims 1-8, characterized in that, it includes: sleeving the metal pipe to be tested outside the connecting rod corresponding to the compression zone, installing the first pressing ring, the elastic member and the second pressing ring, and the end of the metal pipe abuts against the end seat and the first pressing ring; adjusting the position of the second pressing ring, applying a load to the metal pipe through the elastic member and the first pressing ring to make the metal pipe under a set axial compression load; placing the compression assembly together with the metal pipe into the test chamber, adjusting the gap between the metal pipe and the test chamber to reach a set gap thermal resistance, filling with inert gas and closing the test chamber; Place the test cartridge in a test reactor or a commercial reactor to receive neutron irradiation.

10. The test method according to claim 9, characterized in that an isothermal body is filled between the connecting rod in the compression zone and the metal pipe to make the temperature distribution of the metal pipe uniform.

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