Experimental device and method for nuclear fuel pull rod damage simulation

Abstract

The invention discloses an experimental device and method for nuclear fuel pull rod damage simulation, and relates to the technical field of fuel rod damage tests.The experimental device comprises a supporting assembly, a pull rod assembly and a scraping assembly; the supporting assembly comprises a box body, a channel extending in the first direction is formed in the box body, and a water lubricating device is arranged at one end opening of the channel. The pull rod assembly is adjacent to the supporting assembly and located at the end opening of the side, away from the water lubricating device, of the box body. The rod pulling assembly comprises a clamping part and a driving part which are matched with each other, the clamping part is used for clamping the fuel rod extending out of the channel, and the driving part is used for driving the fuel rod to move in the first direction; the scraping assembly is arranged in the box body, the scraping assembly comprises multiple sets of profiling tool bit pieces arranged in the first direction so as to scrape the moving fuel rod, and by means of the device, the damage forming mechanism and key influence factors of the fuel rod can be accurately analyzed conveniently.

Description

Technical Field

[0001] The present application generally relates to the technical field of fuel rod damage testing, and in particular to an experimental device and method for simulating nuclear fuel rod damage. Background Art

[0002] During nuclear fuel assembly, the rod drawing process is a critical step in inserting the fuel rods into the grid. During this process, the fuel rods must overcome the clamping force of the grid springs and the rigid cams, resulting in frictional contact and zirconium alloy scraping (referred to as zirconium shavings) on their surfaces.

[0003] Fuel rods are subjected to extreme conditions of high temperature, high pressure, and strong radiation during long-term service in the reactor. Surface damage can lead to stress concentration and increased corrosion, which in turn degrades the integrity of the cladding and ultimately affects the safe life of the assembly. Therefore, quantitatively studying the formation mechanism and key influencing factors of fuel rod surface damage during the rod drawing process is of great engineering value for optimizing process parameters and extending the service life of fuel assemblies. Summary of the Invention

[0004] In view of the above-mentioned defects or deficiencies in the prior art, it is desired to provide an experimental device and method for simulating nuclear fuel rod damage.

[0005] In a first aspect, the present application provides an experimental device for simulating nuclear fuel rod damage, comprising: A support assembly comprising: a box having a passage extending in a first direction therein, the passage being used to transport experimental fuel rods; a water lubrication device provided at one end of the passage, the water lubrication device being used to spray water onto the fuel rods inserted into the box to moisten the surfaces of the fuel rods; A rod puller assembly is disposed adjacent to the support assembly and is located at a port of the box body on a side away from the water lubrication device; the rod puller assembly includes a clamping portion and a driving portion that cooperate with each other, the clamping portion being used to clamp the fuel rod extending from the channel, and the driving portion being used to drive the fuel rod to move along the first direction; A scraping assembly is arranged inside the box, and the scraping assembly includes a plurality of groups of contoured cutter heads arranged along the first direction, and the contoured cutter heads are used to scrape the moving fuel rods to provide data information for the damage experiment.

[0006] According to the technical solution provided in this application, the interior of the box is partially hollow to form an installation space; the scraping assembly is arranged at the top of the installation space, and through holes are opened on both sides of the box, and the through holes are connected to the installation space to form the channel for transporting fuel rods; the water lubrication device is arranged at the through hole on the side away from the pulling rod assembly.

[0007] According to the technical solution provided in this application, the support assembly further includes: a first sleeve, the first sleeve being arranged in the installation space and located at the bottom of the box body, a support hole being provided in the middle of the first sleeve, the support hole being arranged corresponding to the through hole, and the support hole being used to support the fuel rod extending through the through hole; The second sleeve is arranged in the installation space and is located at the bottom of the box body; the top of the second sleeve is a semicircular structure, and the semicircular structure is matched with the fuel rod; the semicircular structure is used to support the fuel rod extending through the through hole; the second sleeve is arranged corresponding to the contoured cutter head.

[0008] According to the technical solution provided in this application, there are multiple first sleeves and second sleeves arranged along the first direction, and the first sleeves are distributed near the through hole. The number of the second sleeves matches the number of contoured cutter head parts, and the two are arranged one-to-one in the middle of the installation space.

[0009] According to the technical solution provided in this application, the pull rod assembly includes: Two bases, the two bases are arranged along the first direction, and a slide rail is provided between the two bases, the slide rail is used to limit the movement direction of the fuel rod; wherein a communication hole is opened in the middle of the base near the box body, the communication hole corresponds to the through hole, and a scratch detection device is also provided in the communication hole; The driving part is arranged on the top of the two bases, and the driving part includes: a motor, and the motor is connected to the screw rod through a coupling; The clamping part includes a connecting rod threadedly connected to the screw rod, the bottom of the connecting rod is slidably connected to the slide rail, and the connecting rod is also provided with a chuck for clamping the fuel rod and a vibration frequency sensor for detecting the speed of the rod assembly. The chuck is also provided with a tension speed sensor.

[0010] According to the technical solution provided in this application, the contoured cutter head comprises: An installation sleeve is provided, one end of which is arranged at the top of the installation space, and the other end is provided with a telescopic part, the end of the telescopic part is connected to a contoured cutter head, and the types of the contoured cutter heads include at least a spring-shaped cutter head and a rigid convex cutter head; a displacement-pressure sensor is also provided on the telescopic part.

[0011] According to the technical solution provided in this application, the experimental device also includes: a humidity sensor and a laser sensor. The humidity sensor is arranged at a through hole provided with a water lubrication device to detect the moisture content of the fuel rod; the laser sensor is arranged in the installation space to detect the height of multiple groups of the contoured cutter head parts.

[0012] In a second aspect, the present application provides an experimental device and method for simulating nuclear fuel rod damage, which is applied to the experimental device described above. The experimental method includes: Monitoring the height values ​​of multiple contoured cutter heads, and if it is determined that the multiple contoured cutter heads are at the same height, initiating damage tests one by one according to multiple sets of preset test parameters; the test parameters include at least: water output of the water lubrication device, rod pulling speed, and vibration frequency; Acquiring scratch images of the fuel rod under different test parameters to obtain multiple sets of first damage test data; The type of the profiling cutter head is changed, and when the height values ​​of the profiling cutter head are consistent, damage tests are started one after another according to multiple sets of preset test parameters to obtain multiple sets of second damage test data; The fuel rod damage influencing factors are analyzed based on the multiple groups of the first damage test data, the second damage test data and the test parameters corresponding to each damage test data.

[0013] According to the technical solution provided by this application, the experimental method also includes: Monitor the sudden change of tension and abnormal vibration frequency during the experiment, and control the shutdown of the damage experimental device when the sudden change of tension or abnormal vibration frequency occurs.

[0014] In summary, the present technical solution specifically discloses an experimental device and method for simulating damage to nuclear fuel rods. The experimental device comprises a support assembly, a rod puller assembly, and a scraping assembly. The support assembly comprises a housing having a channel extending in a first direction for conveying experimental fuel rods. A water lubrication device is provided at one end of the channel for spraying water onto the fuel rods extending into the housing to moisten the fuel rod surfaces. The rod puller assembly is disposed adjacent to the support assembly and located at the end of the housing away from the water lubrication device. The rod puller assembly comprises a cooperating clamping portion and a driving portion. The clamping portion is configured to clamp the fuel rod extending from the channel, and the driving portion is configured to drive the fuel rod to move in the first direction. The scraping assembly is disposed within the housing and comprises a plurality of profiled blades arranged along the first direction. The profiled blades are configured to scrape the moving fuel rods to provide data information for damage experiments.

[0015] There is currently a lack of dedicated equipment for accurately simulating damage testing under dynamic contact force of pull rods, making it impossible to accurately and conveniently analyze the damage formation mechanism of the fuel rod surface. The present application provides an experimental device that can simulate fuel rod damage by setting up a support assembly, a pull rod assembly and a scraping assembly. In order to simulate dynamic contact force, a water lubrication device, a clamping part and a driving part are provided in the test device, so that test parameters such as the degree of water wetting, pulling speed and vibration frequency can be adjusted. In conjunction with the scraping assembly, it is convenient to accurately analyze the damage formation mechanism and key influencing factors of the fuel rod, which has important engineering value for the subsequent optimization of process parameters and extension of the service life of the fuel assembly. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Other features, objects and advantages of the present application will become more apparent upon reading the detailed description of non-limiting embodiments made with reference to the following drawings: Figure 1 This is a schematic diagram of the overall structure of an experimental device for simulating nuclear fuel rod damage; Figure 2 A cross-sectional view of an experimental device for simulating damage in nuclear fuel rods.

[0017] Figure 3 Schematic diagram of the structure of the scraping component.

[0018] Figure 4 Schematic diagram of the flow of an experimental method for simulating nuclear fuel rod damage.

[0019] Numbers in the figure: 1. Box body; 11. Through hole; 2. Fuel rod; 3. Water lubrication device; 4. Clamping part; 41. Connecting rod; 42. Chuck member; 43. Vibration frequency sensor; 44. Tension speed sensor; 5. Driving part; 51. Motor; 52. Coupling; 53. Screw; 6. Contoured cutter head; 7. First sleeve; 8. Second sleeve; 9. Base; 91. Connecting hole; 10. Slide rail; 12. Scratch detection device; 13. Mounting sleeve; 14. Telescopic member; 15. Humidity sensor; 16. Displacement-pressure sensor; 01. Spring-shaped cutter head; 02. Rigid convex cutter head. DETAILED DESCRIPTION

[0020] The present application will be further described in detail below with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are merely for the purpose of explaining the relevant invention and are not intended to limit the invention. It should also be noted that, for ease of description, only portions relevant to the invention are shown in the accompanying drawings.

[0021] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments in this application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0022] Example 1 In order to make the technical solutions of the embodiments of the present application clearer and easier to understand, the application background of the embodiments of the present application is introduced below.

[0023] During the assembly of nuclear fuel assemblies, the rod drawing process is a key step in inserting the fuel rods into the positioning grid. The fuel rods need to overcome the clamping force of the grid spring and the rigid cam. Frictional contact on their surfaces causes zirconium alloy scraping (zirconium chips). When serving in the reactor, the fuel rods are subjected to extreme conditions of high temperature, high pressure and strong radiation for a long time. Surface damage can easily lead to stress concentration, increased corrosion and other problems, resulting in a decrease in cladding integrity and affecting the safe life of the assembly.

[0024] At present, there is a lack of experimental equipment in this field, that is, there is a lack of special equipment that can accurately simulate the dynamic contact force of rod pulling. General-purpose friction testing machines are unable to reproduce the rigid-convex geometric characteristics of the frame and the multi-parameter coupling working conditions; traditional equipment has difficulty in achieving high-resolution closed-loop adjustment of the normal load, speed and spacing of the cutter head, resulting in large discreteness of the experimental data and insufficient control accuracy; at the same time, after the test, the traditional equipment has difficulty in establishing a quantitative relationship between process parameters and damage degree due to the immature real-time measurement technology of zirconium chip generation and surface scratch depth, which also leads to the problem of difficulty in quantifying damage. Therefore, there is an urgent need for a special equipment to quantitatively study the surface damage formation mechanism and key influencing factors of the fuel rod during the rod pulling process, which will provide important reference significance and industrial value for the subsequent optimization of process parameters and extension of the service life of fuel assemblies.

[0025] Specifically, please refer to Figure 1 The schematic diagram of the structure of an experimental device for simulating damage to a nuclear fuel rod provided by this embodiment includes: The support assembly includes: a box body 1 having a channel extending in a first direction therein for conveying experimental fuel rods 2; a water lubrication device 3 provided at one end of the channel for spraying water onto the fuel rods 2 extending into the box body 1 to moisten the surfaces of the fuel rods 2; The rod puller assembly is disposed adjacent to the support assembly and is located at the end of the housing 1 on the side away from the water lubrication device 3. The rod puller assembly includes a clamping portion 4 and a driving portion 5 that cooperate with each other. The clamping portion 4 is used to clamp the fuel rod 2 extending from the channel, and the driving portion 5 is used to drive the fuel rod 2 to move in the first direction. The scraping assembly is arranged inside the box body 1 and includes a plurality of groups of contoured cutter heads 6 arranged along a first direction. The contoured cutter heads 6 are used to scrape the moving fuel rods 2 to provide data information for damage experiments.

[0026] In the embodiment of the present application, the support assembly is a core component for supporting and guiding the movement of the fuel rod 2 (nuclear fuel rods can be selected). The interior of the box 1 has a channel extending along a first fixed direction. The first direction is the direction in which the fuel rod 2 moves. For details, see Figure 2 in the horizontal direction; in order to make the damage of the fuel rod 2 more consistent with the actual use scenario of the fuel rod 2, the channel inside the box 1 is further provided with a water lubrication device 3 at a port formed on the side wall of the box. The water lubrication device 3 has the function of spraying water toward the fuel rod 2 to simulate the high-temperature and high-pressure water medium that the fuel rod 2 may contact during service, thereby obtaining the phenomenon of surface lubrication. Through water film lubrication, the friction environment when the fuel rod is in contact with water can be partially reproduced, and the inhibitory effect of the lubricating medium on friction damage can be further studied.

[0027] The rod pulling assembly is a core component used to apply tension to the fuel rod 2. The rod pulling assembly is used in conjunction with the support assembly and is arranged adjacent to each other. The channel in the support assembly runs through the entire box 1, so the fuel rod 2 extends from one end of the channel and extends from the other end. The rod pulling assembly is located on the side where the fuel rod 2 extends and clamps the fuel rod 2 through the clamping part 4. In order to allow the fuel rod 2 to be driven to move, the rod pulling assembly also includes a driving part 5, which drives the clamping part 4 to move, thereby indirectly driving the fuel rod 2 to move.

[0028] The scraping assembly is the core component used to scrape the fuel rods 2. The scraping assembly includes multiple sets of contoured cutter heads 6, and the contoured cutter heads 6 are not of a single type, which can better fit the actual service environment of the fuel rods 2. The contoured cutter heads 6 can contact the surface of the fuel rods 2. At the same time, during the movement of the fuel rods 2, the contoured cutter heads 6 will leave scratches on its surface. The depth, length, extension direction and other information of the scratches are all used as data information of the damage experiment to reflect the current damage status of the fuel rods 2.

[0029] In a preferred embodiment, see Figure 2 The interior of the box body 1 is partially hollow to form an installation space; the scraping assembly is arranged at the top of the installation space, and through holes 11 are opened on both sides of the box body 1. The through holes 11 are connected to the installation space to form a channel for conveying the fuel rods 2; the water lubrication device 3 is arranged at the through holes 11 away from the rod pulling assembly.

[0030] Specifically, in actual application, the upper half of the box body 1 is hollow, which is used to provide installation space for components such as the scraping assembly, and is also the space for forming the channel of the fuel rod 2; through holes 11 connected to the installation space are opened on both sides of the box body 1, and the aperture of the through holes 11 meets the transmission requirements of the fuel rod 2. The fuel rod 2 can extend into the installation space through the through holes 11 and then pass through the through holes 11 on the other side.

[0031] The water lubrication device 3 needs to spray water on the entire fuel rod 2 , so the water lubrication device 3 is provided at the through hole 11 through which the fuel rod 2 will pass when extending into the box 1 .

[0032] In a preferred embodiment, the support assembly further comprises: The first sleeve 7 is arranged in the installation space and is located at the bottom of the box body 1. A support hole is provided in the middle of the first sleeve 7. The support hole is provided corresponding to the through hole 11 and is used to support the fuel rod 2 extending through the through hole 11; The second sleeve 8 is arranged in the installation space and is located at the bottom of the box body 1; the top of the second sleeve 8 is a semicircular structure, which is matched with the fuel rod 2; the semicircular structure is used to support the fuel rod 2 extending through the through hole 11; the second sleeve 8 is arranged corresponding to the contoured cutter head 6.

[0033] Specifically, the embodiment of the present application takes into account the stable transmission of the fuel rod 2 to avoid interference with data such as scratches caused by shaking, and also facilitates the passage of the fuel rod 2. Therefore, a plurality of first sleeves 7 and second sleeves 8 arranged along the first direction are also provided in the installation space.

[0034] Among them, the first sleeve 7 is arranged inside the box body 1 and installed at the bottom of the box body 1. Since the box body 1 is not partially hollow, the bottom of the box body 1 is also slightly higher; a support hole is provided in the middle of the first sleeve 7, and the fuel rod 2 extending from the through hole 11 will also pass through the support hole in sequence; the second sleeve 8 is arranged corresponding to the contour cutter head 6 in the vertical direction. When the contour cutter head 6 scrapes the surface of the fuel rod 2, the second sleeve 8 provides a reaction force for the fuel rod 2 when it is subjected to pressure from multiple groups of contour cutter heads 6, thereby preventing the fuel rod 2 from being greatly deformed by unilateral pressure; for example, when the contour cutter head 6 needs to apply a large force to the fuel rod 2, the design of the second sleeve 8 will make the force on the fuel rod 2 more stable.

[0035] In a preferred embodiment, multiple first sleeves 7 and second sleeves 8 are arranged along the first direction, and the first sleeves 7 are distributed near the through hole 11. The number of second sleeves 8 matches the number of contoured cutter head parts 6, and the two are arranged one-to-one in the middle of the installation space.

[0036] The arrangement of multiple groups of first sleeves 7 and second sleeves 8 can be arranged as follows: the number of first sleeves 7 is two, and they are respectively distributed at positions close to the two through holes 11. The number of second sleeves 8 matches the number of contoured cutter heads 6. For example, three are selected, and three second sleeves 8 and contoured cutter heads 6 are arranged in the middle of the installation space in a one-to-one correspondence. It should be explained that the design of the number and position of the first sleeves 7 and the second sleeves 8 can be set according to actual needs. This is only an example. At the same time, the material hardness of the first sleeves 7 and the second sleeves 8 should be as small as possible and the surface roughness should be as low as possible to prevent additional scratches on the fuel rods 2 and interference with the final experimental accuracy.

[0037] In a preferred embodiment, see Figure 2 , the pull rod assembly includes: Two bases 9 are arranged along a first direction, and a slide rail 10 is provided between the two bases 9. The slide rail 10 is used to limit the movement direction of the fuel rod 2. A communication hole 91 is opened in the middle of the base 9 near the box body 1. The communication hole 91 corresponds to the through hole 11, and a scratch detection device 12 is also provided in the communication hole 91. The driving part 5 is arranged on the top of the two bases 9, and the driving part 5 includes: a motor 51, and the motor 51 is connected to the screw rod 53 through a coupling 52; The clamping part 4 includes a connecting rod 41 threadedly connected to the screw rod 53, the bottom of the connecting rod 41 is slidably connected to the slide rail 10, and the connecting rod 41 is also provided with a chuck part 42 for clamping the fuel rod 2 and a vibration frequency sensor 43 for detecting the speed of the rod assembly. A tension speed sensor 44 is also provided at the chuck part 42.

[0038] Specifically, the two bases 9 in the rod pulling assembly are used to form an installation space for components such as the driving part 5 and the clamping part 4. Similarly, in order to allow the fuel rod 2 to extend into the clamping part 4, a connecting hole 91 is required to be opened in the middle of the base 9 near the box body 1. In this way, the fuel rod 2 can be connected to the chuck part 42 via the connecting hole 91; the scratch detection device 12 is arranged in the connecting hole 91 and can directly obtain various data information of the current fuel rod 2 after being acted upon by the profiling cutter head 6, such as the scratch depth, length and extension direction, etc., which are not specifically limited here.

[0039] Next, the driving unit 5 is straddled on top of the two bases 9 via a motor mounting base. The driving unit 5 is selected to be a combined transmission structure of a motor 51, a coupling 52 and a screw 53 (the motor 51 drives the screw 53 to rotate, so that the connecting rod 41 moves linearly) to complete the movement of the fuel rod 2; in order to guide the movement of the fuel rod 2, a slide rail 10 is further provided between the two bases 9, and the extension direction of the slide rail 10 must also be the first direction; the clamping unit 4 includes a connecting rod 41 slidably connected to the slide rail 10, so that the connecting rod 41 can move along the slide rail 10; the chuck member 42 on the connecting rod 41 can be selected to be a three-jaw chuck, thereby stably clamping the fuel rod 2.

[0040] It should be explained that, since the aforementioned embodiment of the present application can improve the experimental conditions for multiple dynamic data, a vibration frequency sensor 43 is also provided on the connecting rod 41, and a tension speed sensor 44 is also provided on the chuck 42. This is because by changing the rotational speed of the motor 51, the tension speed of the fuel rod 2 and the vibration frequency generated by the device will change. In order to accurately reflect the relationship between the scratch change and the tension speed and vibration frequency, the vibration frequency sensor 43 and the tension speed sensor 44 are specially provided here.

[0041] In a preferred embodiment, see Figure 2 and Figure 3 , the contoured cutter head 6 comprises: The mounting sleeve 13 has one end arranged at the top of the mounting space and a telescopic member 14 arranged at the other end. The end of the telescopic member 14 is connected to a contoured cutter head, and the types of contoured cutter heads include at least a spring-shaped cutter head and a rigid convex cutter head. A displacement-pressure sensor 16 is also arranged on the telescopic member 14.

[0042] Specifically, in actual application, the contoured cutter head 6 is arranged at the top of the installation space, and is moved toward the fuel rod 2 by the telescopic member 14, thereby contacting the fuel rod 2. The displacement-pressure sensor 16 is used to monitor the movement distance of the telescopic member 14 in real time, and at the same time collect the pressure of the contoured cutter head applied to the fuel rod 2, so as to reflect the interaction state between the contoured cutter head 6 and the fuel rod 2; the positioning grid of the nuclear fuel assembly usually includes a spring structure and a rigid convex structure, so in theory the fuel rod 2 will be subject to the clamping constraints of the two, so the use of a spring-shaped cutter head and a rigid convex cutter head can make the damage experiment closer to the actual rod pulling condition, and the spring-shaped cutter head and the rigid convex cutter head are both fixed to the cutter head base on the telescopic end of the telescopic member 14 by bolt connection, which is convenient for technicians to replace the cutter head type.

[0043] At the same time, the mechanical properties of the spring-shaped and rigid-convex cutter heads differ significantly, allowing the damage mechanisms under different contact modes to be explored separately. The elastic deformation produced by the spring-shaped cutter head 01 causes the contact pressure to change dynamically with the displacement of the pull rod; the rigid-convex cutter head 02 provides a relatively constant normal load for rigid contact. Based on this difference, the different tool types in the fuel rod 2 damage test will ultimately produce different zirconium chip production and scratch distribution, making it easier to explore the damage mechanism of fuel rod 2.

[0044] In a preferred embodiment, the experimental device also includes: a humidity sensor 15 and a laser sensor. The humidity sensor 15 is arranged at the through hole 11 where the water lubrication device 3 is provided, and is used to detect the moisture content of the fuel rod 2; the laser sensor is arranged in the installation space, and is used to detect the height of multiple groups of contoured cutter head parts 6.

[0045] Specifically, in addition to the sensors mentioned above, it also includes: a humidity sensor 15 and a laser sensor. The humidity sensor 15 here can monitor the water output of the water lubrication device 3 to prevent the water lubrication device 3 from being blocked or other abnormalities that cause the water to be unable to spray water normally. In addition, the laser sensor is used to monitor the height of multiple groups of contoured cutter heads 6 to avoid inconsistent cutter head heights. It also assists technicians in adjusting the heights of multiple groups of contoured cutter heads 6. For example, if the cutter head height of a certain contoured cutter head 6 is higher, the corresponding telescopic part 14 can be controlled to start and the contoured cutter head 6 can be moved down so that each contoured cutter head 6 maintains a certain height or a height difference within an acceptable error range.

[0046] Based on the above description, it can be seen that the present application proposes an experimental device for simulating damage to nuclear fuel rods. The specific working principle of the experimental device is as follows: first, confirm the type of cutter head used and fix the cutter head on the cutter head base; then, the fuel rod 2 to be subjected to the damage test is sent into the box body 1 through the through hole 11. At this time, the fuel rod 2 will pass through the support hole on the first sleeve 7 and the semicircular structure on the top of the second sleeve 8 in sequence, extend from the support hole and the through hole 11 on the other side of the first sleeve 7, and then extend into the connecting hole 91 to enter the range of the slide rail 10 and be clamped with the chuck part 42.

[0047] At the beginning of the test, the clamping portion 4 is located on the side close to the box body 1. After it is connected to the fuel rod 2, the multiple sets of contoured blades 6 are controlled to adjust their positions to ensure that they are highly consistent and in contact with the surface of the fuel rod 2. Then, the motor 51 is started, and the fuel rod 2 is driven by the motor 51 to continuously move away from the box body 1. The part of the fuel rod 2 scraped by the contoured blade 6 will also move with it and be detected by the scratch detection device 12 located at the connecting hole 91.

[0048] Example 2 Combine Figure 4Based on the experimental apparatus described in Example 1, this embodiment of the present application proposes an experimental method for simulating nuclear fuel rod damage, which includes: S100, monitoring the height values ​​of the plurality of contoured cutter heads 6, and if it is determined that the plurality of contoured cutter heads 6 are at the same height, initiating damage tests one by one according to a plurality of preset sets of different test parameters; the test parameters including at least: water output of the water lubrication device, rod pulling speed, and vibration frequency; Combined with the above introduction to the damage experimental device, it can be seen that a laser sensor is installed inside the box 1, so at the beginning of the experiment, it is necessary to obtain the cutter head positions of multiple contoured cutter head parts 6 through the laser sensor and calculate the height deviation of each cutter head to make a height consistency judgment. This is to avoid the discreteness of damage data caused by uneven contact pressure. For example, if a cutter head is too low, it will cause local overload, making the scratch depth abnormal.

[0049] It should be noted that the same height here allows for reasonable errors. For example, the height threshold is set to ±5μm. If the height difference of all tool heads is within the threshold, it is determined to be "the same height"; if it exceeds the threshold, the tool head position is fine-tuned by the telescopic part 14.

[0050] When conducting damage experiments, the embodiments of the present application introduce a variety of test parameters, and multiple groups of tests will be conducted according to different experimental parameters to comprehensively analyze the damage mechanism; illustratively, in the experiment, the preset test parameters are, for example: adjusting the water output of the water lubrication device (such as a gradient of 0.1-1L / min), the rod pulling speed (5-60mm / s), and the motor vibration frequency (10-100Hz) in sequence; in addition, it can also include: rod pulling force (10-100N), cutter head-rod clamping force (10-100N), and cutter head-rod interference distance (0-1mm). Multiple damage tests can be performed under each set of test parameter combinations, and no special restrictions are made here; in addition, since a displacement-pressure sensor is also provided at the contoured cutter head part 6, the cutter head force, that is, the pressure of the cutter head on the fuel rod 2, can also be introduced when selecting the test parameters. This pressure has a more direct impact on the depth of the scratch, and the pressure force can be adjusted by the telescopic part 14.

[0051] S200, acquiring scratch images of the fuel rod under different test parameters to obtain multiple sets of first damage test data; Specifically, the scratch image data can be obtained by the scratch detection device 12. The scratch detection device 12 can use a microscope to scan the fuel rod surface in real time and generate a corresponding image that can be used for reference and feature extraction. At the same time, in actual applications, the mass of zirconium chips in a single experiment can be weighed through a debris collection device as an indicator in the damage test data.

[0052] Finally, the scratch parameters are recorded synchronously with the corresponding parameters such as water lubrication amount, rod pulling speed, vibration frequency, etc. to form multiple sets of first damage test data. In this way, multi-dimensional data is formed to avoid the one-sidedness of a single indicator and effectively quantify the degree of damage.

[0053] S300, replacing the type of the profiling cutter head 6, and when the height values ​​of the profiling cutter head 6 are consistent, starting damage tests one by one according to multiple sets of preset test parameters to obtain multiple sets of second damage test data; The type of the aforementioned profiling cutter head 6 also affects the damage to the fuel rod 2. Therefore, in order to fully cover the operating conditions, it is necessary to replace the type of profiling cutter head 6 and conduct the experiment again. Similarly, multiple sets of second damage test data are obtained, which can be used to further study the influence of grid geometric parameters (such as rigid cam angle and spring stiffness) on damage. It can be seen that this damage test device can cover multiple operating condition simulations. Because water lubrication affects friction heat distribution, rod pulling speed determines dynamic contact time, and vibration frequency simulates motor operation disturbances, by combining multiple parameters, different process conditions in actual production (such as different grid models, different assembly speeds, etc.) can be reproduced to generate more comprehensive data.

[0054] S400 , analyzing and obtaining fuel rod damage influencing factors based on multiple sets of first damage test data, second damage test data, and test parameters corresponding to each damage test data.

[0055] Specifically, the embodiment of the present application classifies the data according to the dimensions of "tool head type-water lubrication amount-rod pulling speed-vibration frequency", and finally normalizes the data using statistical software (such as Python's Pandas library), and calculates the correlation between each parameter and the damage index (scratch depth, zirconium chip quality) through correlation analysis to identify key influencing factors.

[0056] In a preferred embodiment, the experimental method further comprises the following steps: Monitor the sudden change of tension and abnormal vibration frequency during the experiment, and control the shutdown of the damage experimental device when the sudden change of tension or abnormal vibration frequency occurs.

[0057] In actual experiments, in order to obtain a large amount of data, multiple experiments need to be carried out. Therefore, in order to further protect the damage experimental device, it is also necessary to monitor the sudden change of tension and abnormal vibration frequency during the experiment in real time, detect abnormal conditions in time, and control the damage experimental device to shut down for protection in time.

[0058] The determination of the sudden change in tension and abnormal vibration frequency here can be obtained by data collection and analysis by the corresponding sensors. For example, if the tension speed sensor detects that the change in tension within 10ms exceeds 20% of the rated tension, it is determined to be a sudden change in tension. The abnormal vibration frequency is determined to be abnormal if the data collected by the mechanical vibration sensor 43 reflects that the motor fundamental frequency amplitude drops by more than 30% compared with the normal operating conditions, or an abnormal peak value of non-rated frequency occurs. The specific determination method is not specifically limited.

[0059] The above description is merely a preferred embodiment of the present application and an illustration of the technical principles employed. Those skilled in the art should understand that the scope of the invention herein is not limited to the technical solutions formed by the specific combination of the above-mentioned technical features, but also encompasses other technical solutions formed by any combination of the above-mentioned technical features or their equivalents without departing from the inventive concept. For example, a technical solution formed by replacing the above-mentioned features with (but not limited to) technical features having similar functions disclosed in this application.

Claims

1. An experimental device for simulating damage to nuclear fuel rods, characterized in that: include: A support assembly, the support assembly comprising: a box (1), the box (1) having a channel extending in a first direction inside, the channel being used to transport experimental fuel rods (2); a water lubrication device (3) being provided at one end of the channel, the water lubrication device (3) being used to spray water onto the fuel rods (2) extending into the box (1) to wet the surface of the fuel rods (2); A rod puller assembly is provided adjacent to the support assembly and is located at a port of the box (1) on a side away from the water lubrication device (3); the rod puller assembly comprises a clamping portion (4) and a driving portion (5) that cooperate with each other, the clamping portion (4) is used to clamp the fuel rod (2) extending from the channel, and the driving portion (5) is used to drive the fuel rod (2) to move along the first direction; A scraping assembly is arranged inside the box (1), and the scraping assembly includes a plurality of groups of contoured cutter heads (6) arranged along the first direction, and the contoured cutter heads (6) are used to scrape the moving fuel rods (2) to provide data information for the damage experiment.

2. The experimental device for simulating damage to nuclear fuel rods according to claim 1, characterized in that: The interior of the box (1) is partially hollow to form an installation space; the scraping assembly is arranged at the top of the installation space; through holes (11) are opened on both sides of the box (1); the through holes (11) are connected to the installation space to form the channel for conveying the fuel rods (2); the water lubrication device (3) is arranged at the through hole (11) on the side away from the rod pulling assembly.

3. The experimental device for simulating damage to nuclear fuel rods according to claim 2, characterized in that: The support assembly further comprises: A first sleeve (7), the first sleeve (7) is arranged in the installation space and is located at the bottom of the box body (1), a support hole is provided in the middle of the first sleeve (7), the support hole is arranged corresponding to the through hole (11), and the support hole is used to support the fuel rod (2) extending through the through hole (11); A second sleeve (8), the second sleeve (8) is arranged in the installation space and is located at the bottom of the box body (1); the top of the second sleeve (8) is a semicircular structure, and the semicircular structure is matched with the fuel rod (2); the semicircular structure is used to support the fuel rod (2) extended through the through hole (11); the second sleeve (8) is correspondingly arranged with the contoured cutter head (6).

4. The experimental device for simulating damage to a nuclear fuel rod according to claim 3, characterized in that: A plurality of the first sleeves (7) and the second sleeves (8) are arranged along the first direction, and the first sleeves (7) are distributed at positions close to the through holes (11). The number of the second sleeves (8) matches the number of the contoured cutter head parts (6), and the two are arranged in a one-to-one correspondence in the middle of the installation space.

5. The experimental device for simulating damage to a nuclear fuel rod according to claim 2, characterized in that: The pull rod assembly comprises: Two bases (9), the two bases (9) are arranged along the first direction, and a slide rail (10) is provided between the two bases (9), the slide rail (10) is used to limit the moving direction of the fuel rod (2); wherein a connecting hole (91) is provided in the middle of the base (9) close to the box body (1), the connecting hole (91) corresponds to the through hole (11), and a scratch detection device (12) is also provided in the connecting hole (91); The driving part (5) is arranged on the top of the two bases (9), and the driving part (5) comprises: a motor (51), and the motor (51) is connected to a screw rod (53) via a coupling (52); The clamping part (4) includes a connecting rod (41) threadedly connected to the screw rod (53), the bottom of the connecting rod (41) is slidably connected to the slide rail (10), and the connecting rod (41) is also provided with a chuck (42) for clamping the fuel rod (2) and a vibration frequency sensor (43) for detecting the speed of the rod assembly, and the chuck (42) is also provided with a tension speed sensor (44).

6. The experimental device for simulating damage to a nuclear fuel rod according to claim 2, characterized in that: The contoured cutter head (6) comprises: A mounting sleeve (13) is provided at one end of the mounting sleeve (13) at the top of the mounting space, and a telescopic member (14) is provided at the other end. The end of the telescopic member (14) is connected to a contoured cutter head, and the types of the contoured cutter heads include at least a spring-shaped cutter head (01) and a rigid convex cutter head (02). A displacement-pressure sensor (16) is also provided on the telescopic member (14).

7. The experimental device for simulating damage to a nuclear fuel rod according to claim 2, characterized in that: The experimental device further comprises: a humidity sensor (15) and a laser sensor. The humidity sensor (15) is arranged at a through hole (11) provided with a water lubrication device (3) and is used to detect the moisture content of the fuel rod (2); and the laser sensor is arranged in the installation space and is used to detect the height of the plurality of groups of the contoured cutter head parts (6).

8. An experimental method for simulating damage to a nuclear fuel rod, characterized in that: The experimental method is applied to the experimental device according to any one of claims 1 to 7, and the experimental method comprises: Monitoring the height values ​​of the plurality of profiling cutter heads (6), and determining if the plurality of profiling cutter heads (6) are at the same height, and starting damage tests one by one according to a plurality of preset groups of different test parameters; the test parameters at least include: water output of the water lubrication device, rod pulling speed, and vibration frequency; Acquiring scratch images of the fuel rod under different test parameters to obtain multiple sets of first damage test data; The type of the profiling cutter head (6) is replaced, and when the height values ​​of the profiling cutter head (6) are consistent, damage tests are started one after another according to a plurality of preset groups of different test parameters to obtain a plurality of groups of second damage test data; The fuel rod damage influencing factors are analyzed based on the multiple groups of the first damage test data, the second damage test data and the test parameters corresponding to each damage test data.

9. The experimental method for simulating damage to a nuclear fuel rod according to claim 8, characterized in that: The experimental method also includes: Monitor the sudden change of tension and abnormal vibration frequency during the experiment, and control the shutdown of the damage experimental device when the sudden change of tension or abnormal vibration frequency occurs.

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