Regional test method and device for researching in-reactor material

Abstract

The invention relates to the technical field of irradiation tests, and provides a regional test method and device for materials in a research reactor, and the test method comprises the following steps: dividing test regions and test stages in the research reactor, and dividing test sample batches according to specific characteristics; the test areas are divided into three types: an area I (a reactor core active section area containing a neutron field, a gamma field and a water chemical environment), an area II (a reactor core non-active section area containing a gamma field and a water chemical environment) and an area III (a reactor core outer loop inner area and only a water chemical environment); the test stages are divided into three classes: a stage I (cold-state working condition, normal temperature, less than or equal to rated pressure and less than or equal to rated flow), a stage II (hot-state normal working condition, rated temperature, rated pressure and rated flow) and a stage III (hot-state reinforced working condition, rated temperature, rated pressure and higher than rated flow). According to the method, the influence factors can be quickly locked by comparing the performance changes and defects of the same batch of samples in three areas after three-stage tests.

Description

Technical Field

[0001] This invention relates to the field of irradiation testing technology, and more specifically, to a method and apparatus for regional testing of materials within a reactor. Background Technology

[0002] Research on in-reactor material irradiation testing is a core component of the research and screening of in-reactor structural materials and fuel cladding materials. Its core value lies in providing new materials with a complex physical field testing environment that closely resembles real-world application scenarios. Within the research reactor, new materials must simultaneously withstand irradiation from neutron and gamma fields, as well as the combined effects of temperature and pressure fields. They must also cope with multiple harsh conditions, including water chemistry erosion and fluid scouring. The main factors affecting their performance include the neutron field, gamma field, water chemistry (temperature, pressure, and water quality), and manufacturing defects in the material itself. These key factors collectively determine the material's service performance and lifespan in actual reactor applications.

[0003] However, current traditional material irradiation testing methods have significant limitations: irradiation-derived defects that appear in new materials after testing are often difficult to pinpoint the cause quickly. Researchers need to wait for a long testing period and go through complex subsequent testing and analysis procedures before they can preliminarily infer whether the defects are caused by neutron irradiation, gamma irradiation, fluctuations in the hydrochemical environment, or defects in the material's own manufacturing process. This process not only significantly extends the research and development cycle of new materials but also significantly increases the economic and time costs in the research and development process, seriously restricting the iteration efficiency of new materials for stacking. Summary of the Invention

[0004] The purpose of this invention is to provide a method and apparatus for regional testing of materials within a reactor core, in order to overcome the aforementioned deficiencies of the prior art.

[0005] This invention is achieved through the following technical solution: A method for regional testing of materials within a reactor core is proposed, which divides the test area and test phase within the reactor core and classifies the test samples into batches according to specific characteristics. The test area is divided as follows: Region 1: The active section of the reactor core, which simultaneously contains a neutron field, a gamma field, and a water chemistry environment; Region 2: The inactive section of the reactor core, which contains both a gamma field and a water chemistry environment; And Region 3: the inner region of the outer loop of the reactor core, which contains a water chemical environment; The experimental phases are divided as follows: Phase 1: Cold operating conditions, the test conditions are room temperature, pressure not exceeding the rated pressure and flow rate not exceeding the rated flow rate; Phase Two: Normal operating conditions under hot conditions, with test conditions being rated temperature, rated pressure, and rated flow rate; And Phase 3: Hot-state enhanced operating conditions, the test conditions are rated temperature, rated pressure and flow rate higher than rated; For the same batch of test samples, the design is to load them into a test device. The test process in the same test device is divided into three stages: stage one, stage two, and stage three. The test device is set up with three regions: region one, region two, and region three. The test samples loaded in the test section of each region are the same. All three regions are on the test circuit. During the test, the coolant is excited by neutrons in the test section of region one and then acts on the test section of region two. The coolant excited in the test section of region two is fully stabilized before acting on the test section of region three. For different batches of test samples, the tests were carried out in different batches in different test devices.

[0006] Furthermore, the test area also includes Region 4: the off-center region, which is located outside the shielded area of ​​the research reactor.

[0007] Furthermore, the trials in Region 4 can be conducted independently, or simultaneously with or prior to the trials in the other three regions.

[0008] Furthermore, specific characteristics of the test sample include the material, size, manufacturing process, manufacturer, and whether it contains a coating.

[0009] Furthermore, Phase 1 corresponds to the transition phase before the research reactor reaches its temperature and power, and its duration is no less than 24 hours; Phase 2 corresponds to the stable operation phase of the research reactor, and its duration is no less than 72 hours; Phase 3 corresponds to the transition phase of the research reactor under accident conditions, and its duration is no less than 48 hours.

[0010] Furthermore, the water chemical environment of the three test sections (Region 1, Region 2, and Region 3) is completely identical, and the flow channel cross-sections of the three test sections are completely identical; the water chemical environment includes the temperature, pressure, flow rate, velocity, and water quality of the coolant.

[0011] The present invention also provides a test apparatus for studying in-core materials in different regions, which adopts the method described in any one of the above, including an insulation tube assembly, a pressure tube assembly, a diversion tube assembly, a connecting tube assembly, a test section in region one, a test section in region two, and a test section in region three; The pressure tube assembly is located inside the adiabatic tube assembly, forming a closed thermal insulation space between the two. The upper end of the adiabatic tube assembly is connected to the research reactor flat top cover, and the lower end of the adiabatic tube assembly is inserted into the research reactor grid plate. The shunt tube assembly is installed inside the pressure tube assembly. The connecting tube assembly is used to connect the pressure tube assembly and the research reactor test loop to form a closed loop for the coolant. The Region 1 test section is installed inside the lower end of the shunt tube assembly, located in the center of the active region within the research reactor; the Region 2 test section is installed inside the upper end of the shunt tube assembly, located outside the active region within the research reactor; and the Region 3 test section is installed inside the connecting tube assembly, located on the test loop outside the research reactor.

[0012] Furthermore, the insulation space between the pressure pipe assembly and the insulation pipe assembly is filled with nitrogen.

[0013] Furthermore, the axial length of the test section in Region 1 is less than the length of the active core region, while the test section in Region 2 is closer to the active core region.

[0014] Furthermore, the insulation tube assembly is externally connected to a pressure relief rupture disc. The design pressure of the pressure tube assembly is defined as P1, the design pressure of the insulation tube assembly is P2, the detonation pressure of the pressure relief rupture disc is P3, and the coolant pressure of the research reactor is P4. It is necessary to satisfy P4 < P3 < P2 < P1.

[0015] The technical solution of the present invention has at least the following advantages and beneficial effects: In the present invention, the test area is divided into three core areas, and the environmental characteristics of each area form a precise gradient difference. Among them, the first area has a neutron field, a gamma field and a water chemical environment, the second area has only a gamma field and a water chemical environment, and the third area has only a water chemical environment. The test samples loaded in the test section of each area are the same, thus constructing a control test system with "unique variables".

[0016] By comparing the performance changes and defects of the same batch of samples in three regions after three stages of testing, the influencing factors can be quickly identified. (If only the sample in region one shows a specific defect, while samples in regions two and three do not, it indicates that the defect is caused solely by neutron irradiation; if samples in regions one and two show the defect, while samples in region three do not, it indicates that the defect is caused by gamma-field irradiation; if samples in all three regions show the defect with consistent characteristics, it indicates that the defect is caused by the hydrochemical environment.) This "comparative" experimental design completely changes the dilemma of "multiple factors superimposed and difficult to separate" in traditional methods. It can quickly locate the cause of defects without complex subsequent detection and analysis, greatly reducing the analytical difficulty and workload for researchers, helping to shorten the development cycle of new materials, and saving economic and time costs. Attached Figure Description

[0017] Figure 1 A schematic diagram illustrating a method for regional testing of materials within a reactor, provided by this invention; Figure 2 A schematic diagram of a test apparatus for studying materials in a reactor core, provided by the present invention; Figure 3 This is a schematic diagram of the connection structure of the insulation pipe assembly, pressure pipe assembly, and shunt pipe assembly. Reference numerals: 1-Region 1, 11-Region 1 test section, 2-Region 2, 21-Region 2 test section, 3-Region 3, 31-Region 3 test section, 4-Region 4, 5-Test apparatus, 51-Insulation tube assembly, 52-Pressure tube assembly, 53-Diverter tube assembly, 54-Connecting tube assembly, 6-Research reactor, 61-Research reactor flat top cover, 62-Research reactor grid plate. Detailed Implementation

[0018] refer to Figure 1 A method for regional testing of materials within a research reactor 6 is disclosed, which divides the test area and test phase within the research reactor 6 and classifies the test samples into batches according to specific characteristics. These specific characteristics include the material, size, manufacturing process, manufacturer, and whether or not a coating is present. For example, in this embodiment, test samples with coatings are classified into batch one, and test samples without coatings are classified into batch two. In other embodiments, the test samples can, of course, be divided into multiple batches using any of the other specific characteristics mentioned above.

[0019] The test area is divided as follows: Region 1: The active section of the reactor core, which simultaneously contains a neutron field, a gamma field, and a water chemistry environment; Region 2: The inactive section of the reactor core, which contains both a gamma field and a water chemical environment; And Region 3: the inner region of the outer loop of the reactor core, which contains a water chemical environment; The experimental phases are divided as follows: Phase 1: Cold operating condition, the test conditions are room temperature, pressure not exceeding the rated pressure and flow rate not exceeding the rated flow rate (i.e.); that is, the test temperature of Phase 1 is room temperature (20℃ or 25℃), the test pressure is the rated pressure or a fixed pressure value specified below the rated pressure (e.g., fixed at 5MPa), and the test flow rate is the rated flow rate or a fixed flow rate value specified below the rated flow rate (e.g., select the rated flow rate). Phase Two: Normal operating conditions under hot conditions, with test conditions being rated temperature, rated pressure, and rated flow rate; that is, the test temperature, test pressure, and test flow rate in Phase Two are the rated temperature, rated pressure, and rated flow rate. And Phase 3: Hot-state enhanced operating condition, the test conditions are rated temperature, rated pressure and flow rate higher than rated; that is, the test temperature in Phase 3 is higher than the rated temperature, the test pressure is the rated pressure, and the test flow rate is a fixed flow rate value that is higher than the rated flow rate (for example, 1.5 times the rated flow rate).

[0020] During the test, Phase 1 corresponds to the transition phase before the research reactor 6 reaches its temperature and power, and lasts for no less than 24 hours; Phase 2 corresponds to the stable operation phase of the research reactor 6, and lasts for no less than 72 hours; Phase 3 corresponds to the transition phase of the research reactor 6 under accident conditions, and lasts for no less than 48 hours.

[0021] For the same batch of test samples, a single test apparatus 5 was designed, comprising three zones: Zone 1, Zone 2, and Zone 3. The test samples loaded in each zone were identical. Furthermore, the hydrochemical environments (including coolant temperature, pressure, flow rate, velocity, and water quality) of Zone 1 (test zone 11), Zone 2 (test zone 21), and Zone 3 (test zone 31) were completely identical, and the flow channel cross-sections of the three test zones were also identical. This ensured a precise gradient difference in the environmental characteristics of the three zones, constructing a control test system with "unique variables." For different batches of test samples, tests were conducted in different batches within different test apparatuses 5.

[0022] All three regions are on the test loop, and the test process in the same test device 5 is divided into three stages: stage one, stage two, and stage three. During the test, the coolant is excited by neutrons in test section 11 of region one and then acts on test section 21 of region two. After the coolant excited in test section 21 of region two is fully stabilized, it acts on test section 31 of region three. In this way, simultaneous testing of "one loading, multiple operating conditions, and multiple stages" is achieved. Compared with the traditional method that requires multiple tests to simulate different environments and operating conditions, this design significantly reduces the repetitive operation and waiting time of the test.

[0023] By comparing the performance changes and defects of the same batch of samples in three regions after three stages of testing, the influencing factors can be quickly identified. (If only sample 1 in region 1 shows a specific defect, while samples 2 and 3 in region 2 do not, it indicates that the defect is caused solely by neutron irradiation; if samples 1 and 2 in region 1 show the defect, while sample 3 in region 3 does not, it indicates that the defect is caused by gamma field irradiation; if samples in all three regions show the defect with consistent characteristics, it indicates that the defect is caused by the hydrochemical environment.) This "single variable control" experimental design completely changes the dilemma of "multiple factors superimposed and difficult to separate" in traditional methods. It can quickly locate the cause of defects without complex subsequent detection and analysis, greatly reducing the analytical difficulty and workload for researchers, helping to shorten the development cycle of new materials, and saving economic and time costs.

[0024] In this embodiment, the test area also includes Region 4: the external region, located outside the research reactor shielding area. It should be understood that Region 1, Region 2, and Region 3 are all located within the research reactor shielding area. In practical applications, the test in Region 4 can be conducted independently. Typically, the test in Region 4 is conducted in advance, in conjunction with the three-stage test, to verify reliability before the test inside the research reactor 6. After the three-stage test in Region 4 is completed, the three-stage tests in Region 1, Region 2, and Region 3 are then conducted. Of course, Region 4 can also be tested simultaneously with the other three regions.

[0025] This embodiment also provides a test device for studying in-core materials in different regions, using the above-mentioned test method, including an insulation tube assembly 51, a pressure tube assembly 52, a diversion tube assembly 53, a connecting tube assembly 54, a test section 11 for region one, a test section 21 for region two, and a test section 31 for region three.

[0026] The pressure tube assembly 52 is located inside the insulation tube assembly 51, forming a closed, insulated space between them. The upper end of the insulation tube assembly 51 is connected to the research reactor flat top cover 61 (forming a sealed pressure boundary), and the lower end of the insulation tube assembly 51 is inserted into the research reactor grid plate 62. In this embodiment, the insulated space between the pressure tube assembly 52 and the insulation tube assembly 51 is filled with nitrogen gas, which is used to detect whether the pressure tube assembly 52 is damaged and to provide insulation. The shunt tube assembly 53 is installed inside the pressure tube assembly 52, i.e., from the inside out, the components are the insulation tube assembly 51, the pressure tube assembly 52, and the shunt tube assembly 53.

[0027] Test section 11 of region one is installed inside the lower end of the splitter assembly 53, located at the center of the active zone within the research reactor; test section 21 of region two is installed inside the upper end of the splitter assembly 53, located outside the active zone within the research reactor; test section 31 of region three is installed inside the connecting pipe assembly 54, located on the test loop outside the research reactor. In this embodiment, the axial length of test section 11 of region one is less than the length of the active zone in the core, ensuring that test section 11 of region one is completely located within the active zone of the core. Test section 21 of region two is close to the active zone of the core, but should be located outside the active zone and not too far from it, ensuring that the coolant is in an excited state and that the gamma dose is at a high level.

[0028] The connecting pipe assembly 54 is used to connect the pressure pipe assembly 52 and the research reactor test loop to form a closed-loop coolant circuit. It is worth noting that, to achieve the above-mentioned method of "the coolant being excited by neutrons in test section 11 of region 1 before acting on test section 21 of region 2, and the coolant excited in test section 21 of region 2 being fully stabilized before acting on test section 31 of region 3," the following setup should be followed: the space between the pressure pipe assembly 52 and the diversion pipe assembly 53 is the coolant flow channel; the insulating pipe assembly 51 should have a coolant inlet and a coolant outlet located outside the insulating space (the connecting pipe assembly 54 connects the coolant inlet and outlet respectively). The coolant outlet connects to the coolant flow channel between the pressure pipe assembly 52 and the branch pipe assembly 53. The coolant outlet connects to the inside of the branch pipe assembly 53. The coolant enters the coolant flow channel between the pressure pipe assembly 52 and the branch pipe assembly 53 from the coolant inlet on the insulation pipe assembly 51, then enters the inside of the branch pipe assembly 53 from the lower end, and then flows out from the coolant outlet on the insulation pipe assembly 51 after passing through the upper end of the branch pipe assembly 53. It then forms a circulation through the connecting pipe assembly 54 and the test circuit.

[0029] The specific structure and connection assembly method of the insulation pipe assembly 51, pressure pipe assembly 52, and diversion pipe assembly 53 are not limited, as long as the above-mentioned flow direction of the coolant can be formed. For example, in this embodiment, the following method is used: Figure 3 The structure shown is as described. In other embodiments, the irradiation structure provided in the prior art can also be directly adopted, such as the irradiation structure disclosed in existing patent documents such as "CN119442954A" and "CN104361918A" to replace the overall structure composed of the heat insulation pipe assembly 51, the pressure pipe assembly 52 and the diversion pipe assembly 53.

[0030] It should be understood that, in addition to the test method including region 4, the test device 5 in this embodiment should also include the test section of region 4 (not shown in the figure). The test section of region 4 is located on an independent loop outside the research reactor shielding area. The independent loop is connected to the test loop and can be opened and closed independently. The independent loop is equivalent to the bypass branch of the test loop outside the research reactor shielding area, and the on and off are achieved through corresponding valves at both ends of the bypass branch.

[0031] In this embodiment, a pressure relief rupture disc (not shown) is externally connected to the heat insulation tube assembly 51. The design pressure of the pressure tube assembly 52 is defined as P1, the design pressure of the heat insulation tube assembly 51 as P2, the detonation pressure of the pressure relief rupture disc as P3, and the coolant pressure of the research reactor 6 as P4. The following conditions must be met: P4 < P3 < P2 < P1. The reason for this configuration is as follows: If the pressure tube assembly 52 ruptures, to prevent the high-pressure coolant in the loop from damaging the heat insulation tube assembly 51, which could lead to rupture of the heat insulation tube assembly 51 and reactor coolant leakage, the pressure relief rupture disc needs to be detonated. If the heat insulation tube ruptures, the pressure relief rupture disc cannot be detonated to prevent reactor coolant leakage. This ensures experimental safety and prevents the leakage of radioactive materials.

[0032] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for studying in-pile materials through regional testing, characterized in that, The test area and test phases within the research reactor were divided, and the test samples were divided into test batches according to specific characteristics; The test area is divided as follows: Region 1: The active section of the reactor core, which simultaneously contains a neutron field, a gamma field, and a water chemistry environment; Region 2: The inactive section of the reactor core, which contains both a gamma field and a water chemistry environment; And Region 3: the inner region of the outer loop of the reactor core, which contains a water chemical environment; The experimental phases are divided as follows: Phase 1: Cold operating conditions, the test conditions are room temperature, pressure not exceeding the rated pressure and flow rate not exceeding the rated flow rate; Phase Two: Normal operating conditions under hot conditions, with test conditions being rated temperature, rated pressure, and rated flow rate; And Phase 3: Hot-state enhanced operating conditions, the test conditions are rated temperature, rated pressure and flow rate higher than rated; For the same batch of test samples, the design is to load them into a test device. The test process in the same test device is divided into three stages: stage one, stage two, and stage three. The test device is set up with three regions: region one, region two, and region three. The test samples loaded in the test section of each region are the same. All three regions are on the test circuit. During the test, the coolant is excited by neutrons in the test section of region one and then acts on the test section of region two. The coolant excited in the test section of region two is fully stabilized before acting on the test section of region three. For different batches of test samples, the tests were carried out in different batches in different test devices.

2. The method for regional testing of materials within a reactor as described in claim 1, characterized in that, The test area also includes Area 4: the off-center area, which is located outside the shielded area of ​​the research reactor.

3. The method for regional testing of materials within a reactor as described in claim 2, characterized in that, The trials in Region 4 can be conducted independently, and can be conducted simultaneously with or before the trials in the other three regions.

4. The method for regional testing of materials within a reactor as described in claim 1, characterized in that, The specific characteristics of the test sample include the material, size, manufacturing process, manufacturer, and whether it contains a coating.

5. The method for regional testing of materials within a reactor as described in claim 1, characterized in that, Phase 1 corresponds to the transition phase before the research reactor reaches its temperature and power, and lasts for no less than 24 hours; Phase 2 corresponds to the stable operation phase of the research reactor, and lasts for no less than 72 hours; Phase 3 corresponds to the transition phase of the research reactor under accident conditions, and lasts for no less than 48 hours.

6. The method for regional testing of materials within a reactor as described in claim 1, characterized in that, The water chemical environment of test sections 1, 2 and 3 is exactly the same, and the flow channel cross-sections of the three test sections are exactly the same; the water chemical environment includes the temperature, pressure, flow rate, velocity and water quality of the coolant.

7. A test apparatus for studying in-core materials in a sectionalized manner, employing the test method described in any one of claims 1-6, characterized in that, It includes insulation pipe assemblies, pressure pipe assemblies, branch pipe assemblies, connecting pipe assemblies, Zone 1 test section, Zone 2 test section and Zone 3 test section; The pressure tube assembly is located inside the adiabatic tube assembly, forming a closed thermal insulation space between the two. The upper end of the adiabatic tube assembly is connected to the research reactor flat top cover, and the lower end of the adiabatic tube assembly is inserted into the research reactor grid plate. The shunt tube assembly is installed inside the pressure tube assembly. The connecting tube assembly is used to connect the pressure tube assembly and the research reactor test loop to form a closed loop for the coolant. The Region 1 test section is installed inside the lower end of the shunt tube assembly, located in the center of the active region within the research reactor; the Region 2 test section is installed inside the upper end of the shunt tube assembly, located outside the active region within the research reactor; and the Region 3 test section is installed inside the connecting tube assembly, located on the test loop outside the research reactor.

8. The in-pile material regional testing apparatus according to claim 7, characterized in that, The insulation space between the pressure pipe assembly and the insulation pipe assembly is filled with nitrogen.

9. The in-pile material regional testing apparatus according to claim 7, characterized in that, The axial length of the test section in Region 1 is less than the length of the active core region, while the test section in Region 2 is closer to the active core region.

10. The in-pile material regional testing apparatus according to claim 7, characterized in that, The insulation tube assembly is externally connected to a pressure relief rupture disc. The design pressure of the pressure tube assembly is defined as P1, the design pressure of the insulation tube assembly is P2, the detonation pressure of the pressure relief rupture disc is P3, and the coolant pressure of the research reactor is P4. The conditions must be met that P4 < P3 < P2 < P1.

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