A dispersion fuel element surface bubbling simulation measurement system and method

Abstract

The application relates to the technical field of reactor thermal hydraulic and safety, in particular to a dispersion type fuel element surface bubbling simulation measurement system and method. The measurement system comprises a heated plate, an adiabatic base, a cover body, a medium inlet piece, a medium outlet piece, a conductive piece, a first measurement device and a second measurement device; the heated plate is provided with a vacuum bubble part; the heated plate is connected to the adiabatic base, and the adiabatic base is provided with a measurement window; the cover body is provided with a flow-through groove and is connected to the adiabatic base to form a narrow gap channel, the light transmittance of the cover body is not less than 98%; the medium inlet piece is communicated with one end of the narrow gap channel; the medium outlet piece is communicated with the other end of the narrow gap channel; the two conductive pieces are connected to the two ends of the heated plate respectively; the first measurement device is located on one side of the adiabatic base; and the second measurement device is located on one side of the cover body. The application can conveniently measure the thermal hydraulic parameters of the heated plate and the medium based on the simulation system, and can provide a reliable basis for the actual dispersion type fuel element thermal hydraulic research.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of reactor thermal hydraulic and safety, in particular to a dispersion type fuel element surface bubbling simulation measurement system and method. BACKGROUND

[0002] The fission gas generated in the dispersion type fuel element under high burnup will be concentrated locally to cause plastic deformation of the fuel, resulting in bubbling phenomenon on the surface of the element. With the increase of the number of bubbles, the flow passage resistance will inevitably increase, and the fission gas will also increase the local thermal resistance in the fuel element, resulting in heat transfer deterioration, and further affecting the integrity of the cladding. At present, there are few studies on the heat transfer performance of the dispersion type fuel element under the bubbling condition, and most of them are numerical simulation studies. Therefore, it is necessary to design a heat transfer real-time simulation system and a synchronous measurement method for multiple bubbling of the dispersion type fuel element, to carry out experimental research on the coolability of the fuel element after bubbling, to obtain the basic experimental data of the fuel element flow and heat transfer under the bubbling condition, and to master the influence law and mechanism of the bubbling condition. SUMMARY

[0003] The present application provides a dispersion type fuel element surface bubbling simulation measurement system and method to solve the problems in the background art.

[0004] The present application is implemented by the following technical solutions:

[0005] In a first aspect, the present application provides a dispersion type fuel element surface bubbling simulation measurement system, comprising:

[0006] A heat receiving plate capable of electrically conducting, one plate surface of the heat receiving plate has a vacuum bubble-shaped part;

[0007] An insulating base, the heat receiving plate is connected to the working surface of the insulating base, and the insulating base has a measurement window corresponding to the position of the vacuum bubble-shaped part and penetrating through the insulating base;

[0008] A cover body, the cover body has a flow-through groove, the cover body is connected with the insulating base to seal the flow-through groove with the insulating base to form a narrow gap channel, the heat receiving plate is located in the narrow gap channel, and the light transmittance of the cover body is configured to be not less than 98%;

[0009] A medium introduction piece, the medium introduction piece is in communication with one end of the narrow gap channel;

[0010] A medium outlet piece, the medium outlet piece is in communication with the other end of the narrow gap channel;

[0011] Conductive pieces, two conductive pieces are respectively connected to two ends of the heat receiving plate;

[0012] a first measuring device, the first measuring device being located on one side of the thermally insulating base for measuring the heated plate through the measuring window;

[0013] A second measuring device is located at one side of the cover to measure the medium in the cover, and the second measuring device is equipped with a laser.

[0014] In some optional embodiments, the first measuring device is configured as an infrared thermal imager.

[0015] In some optional embodiments, the second measurement device is configured as a high-speed camera or a cross-frame camera.

[0016] In some optional embodiments, a synchronizer is further included, and the first measuring device and the second measuring device are respectively connected to the synchronizer.

[0017] In some optional embodiments, the cover body is sealed to the thermal insulation base via a static sealing ring, wherein the static sealing ring is arranged around the flow groove.

[0018] In some optional embodiments, a mounting sink is constructed on the working surface of the thermal insulation base, the heated plate is connected to the mounting sink, and one of the plate surfaces is flush with the working surface.

[0019] In some optional embodiments, the heated plate is connected to the inner wall of the mounting sink by filling with sealant.

[0020] In some optional embodiments, the cover is configured as optical quartz glass.

[0021] In some optional embodiments, the insulating base is configured as an insulator.

[0022] In some optional embodiments, the thermally insulating base is configured as a resin body.

[0023] In some optional embodiments, the conductive member is connected to the heated plate by silver brazing.

[0024] In some optional embodiments, an elastic sealing cavity is provided in the insulating base, and the elastic sealing cavity is filled with insulating powder. A temperature measuring hole is also provided on the insulating base so that the thermocouple can pierce the elastic sealing cavity through the temperature measuring hole and contact the heated plate.

[0025] In some optional embodiments, a pressure measuring pipe is further included, and the pressure measuring pipe is connected to the narrow slit channel.

[0026] In some optional embodiments, the medium inlet and / or medium outlet is equipped with a temperature measuring pipe.

[0027] In some optional embodiments, a first pressure-bearing block and a second pressure-bearing block are arranged at intervals, and the first pressure-bearing block is connected to the second pressure-bearing block, wherein the first pressure-bearing block abuts against the base, and the second pressure-bearing block abuts against the cover.

[0028] In some optional embodiments, the heated plate comprises:

[0029] A foaming plate, wherein the foaming plate is formed with grooves through a casting process;

[0030] A heating plate, the heating plate and the bubbling plate are arranged in parallel and spaced apart;

[0031] An insulating layer is located between the blister plate and the heating plate, the insulating layer is connected to the heating plate, and the insulating layer and the blister plate are connected by vacuum diffusion welding to enclose a vacuum bubble portion with the groove on the blister plate.

[0032] In a second aspect, the present application provides a method for simulating and measuring bubbling on the surface of a dispersed fuel element, which is implemented based on the system for simulating and measuring bubbling on the surface of a dispersed fuel element described in the first aspect and includes the following contents:

[0033] Providing a medium so that the medium circulates in the narrow channel;

[0034] Providing power to make the heated plate electrically conductive;

[0035] Adding tracer particles to the medium;

[0036] Adjust the laser so that the laser emission direction coincides with the medium flow direction;

[0037] The first measuring device and the second measuring device are activated to measure the heated plate and the medium.

[0038] Compared with the prior art, this application has the following advantages and beneficial effects:

[0039] The present application provides a system and method for simulating and measuring bubbling on the surface of a dispersed fuel element. The vacuum bubble portion on the heated plate can simulate the structural state of the dispersed fuel element under bubbling, and a narrow channel is formed by connecting the cover body and the insulating base. The medium is allowed to flow in the narrow channel by using a medium inlet and a medium outlet, and the heated plate is heated by using a conductive member. At the same time, the heated plate realizes unilateral diffusion of heat into the narrow channel under the insulating effect of the insulating base, and can obtain the same heating conditions and heat transfer conditions as those when the dispersed fuel element is bubbling, and provide a coolant thermal boundary consistent with that when the dispersed fuel element is bubbling, thereby realizing accurate simulation of the heating boundary of the dispersed fuel element and the geometric boundary of the flow channel. Then, the temperature parameters of the heated plate can be automatically measured through the measurement window by using the first measuring device, and the medium parameters in the narrow channel can be automatically measured by using the second measuring device. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the technical solutions of the exemplary embodiments of the present application, the following briefly introduces the drawings required for use in the examples. It should be understood that the following drawings only illustrate certain embodiments of the present application and should not be considered as limiting the scope. A person of ordinary skill in the art can also derive other relevant drawings based on these drawings without inventive effort. In the drawings:

[0041] Figure 1 A simplified structural diagram of a system for simulating and measuring the bubbling on the surface of a dispersed fuel element provided in an embodiment of the present application;

[0042] Figure 2 A schematic diagram of a structure for simulating the bubble state on the surface of a dispersed fuel element provided in an embodiment of the present application;

[0043] Figure 3 for Figure 2 Schematic diagram of the cross-sectional structure at AA in the middle;

[0044] Figure 4 A schematic diagram of a cross-sectional structure of a heat-insulating base provided in an embodiment of the present application;

[0045] Figure 5 This is a schematic diagram of the heated plate structure provided in an embodiment of the present application.

[0046] Markings and corresponding parts names in the accompanying drawings:

[0047] 1-medium inlet, 2-medium outlet, 3-second pressure-bearing block, 4-cover, 5-heating plate, 51-foaming plate, 52-heating plate, 53-insulating layer, 6-insulating base, 61-elastic sealing cavity, 62-insulating powder, 7-narrow slit channel, 8-conductive part, 9-first pressure-bearing block, 10-temperature measuring hole, 11-temperature measuring pipe, 12-pressure measuring pipe, 13-first measuring device, 14-second measuring device, 15-laser, 16-synchronizer. DETAILED DESCRIPTION

[0048] In order to make the objectives, technical solutions and advantages of this application more clear, the present application is further described in detail below in conjunction with examples and drawings. The schematic implementation methods of this application and their descriptions are only used to explain this application and are not intended to limit this application.

[0049] In the first aspect, the present invention provides a system for simulating and measuring the surface bubbling of a dispersed fuel element. Figures 1 to 4 The dispersion-type fuel element surface bubbling simulation measurement system includes a heated plate 5, an insulating base 6, a cover 4, a medium inlet 1, a medium outlet 2, a conductive member 8, a first measuring device 13 and a second measuring device 14.

[0050] The heated plate 5 can be configured as an electrically conductive material plate. When the heated plate 5 is electrically conductive, the heated plate generates heat by doing work through current to simulate the heat release of a diffuse fuel element. For example, the heated plate 5 can be configured as a material such as copper, aluminum, iron, nickel-chromium alloy, silicon, germanium, silicon carbide, gallium arsenide, carbon fiber, graphite, carbon nanotubes, ceramic fibers, carbon-based composite plates, etc. One of the surfaces of the heated plate 5 has a vacuum bubble portion, which is manifested as a hollow protrusion on one of the surfaces of the heated plate 5. The vacuum bubble portion can be formed by casting or by connecting two components to each other, and the hollow protrusion contains a vacuum cavity; the number of vacuum bubble portions can be one or more. When the number of vacuum bubble portions is multiple, the multiple vacuum bubble portions can be arranged adjacent to each other, that is, the edges of the vacuum bubble portions are connected, or they can be arranged at intervals, that is, there is a distance between any two vacuum bubble portions.

[0051] The heated plate 5 is connected to the working surface of the insulating base 6. The specific shape of the insulating base 6 is not limited. It can be constructed into a shape such as a cuboid, a triangular prism, a quadrangular prism, a polygonal prism, a sphere or other special shapes; the working surface on the insulating base 6 can be a plane to facilitate the connection of other components, as in the embodiment of the present application. When the heated plate 5 is heated, its plate surface has a large heat diffusion area. The plate surface of the heated plate 5 can be fitted with the working surface of the insulating base 6 to reduce heat dissipation and realize unilateral diffusion of heat from the heated plate 5, wherein the vacuum bubble portion is located on the plate surface of the heated plate 5 away from the insulating base 6; the working surface can be obtained by processing, or it can be a plane of the insulating base 6 itself. For example, when the heat-insulating base 6 is constructed as a sphere, a working surface can be obtained on the heat-insulating base 6 by turning, milling, planing and other processing methods. For example, when the heat-insulating base 6 is constructed as a rectangular parallelepiped, one of the side surfaces of the heat-insulating base 6 can be used as the working surface. In actual experimental operations, the heat-insulating base 6 usually needs to be fixed or clamped by other components, so the heat-insulating base 6 can be constructed as a rectangular parallelepiped to facilitate the experimenter to perform necessary operations. At this time, the outline shape of the working surface is a rectangle. Of course, the specific shape of the working surface is not limited. In other embodiments, even if the heat-insulating base 6 is constructed as a rectangular parallelepiped, the outline shape of one of the side surfaces of the heat-insulating base 6 can be processed into a triangle, a pentagon, a hexagon, or the like. A working surface of a polygonal, star-shaped or other special-shaped shape; the insulating base 6 has a measuring window corresponding to the position of the vacuum bubble and passing through the insulating base 6, the measuring window can be configured as a rectangular through hole, the size of the rectangular through hole can be adaptively designed, and its specific size is configured so that when the heated plate 5 is heated to the expected maximum value, the bending deformation of the portion of the heated plate 5 corresponding to the position of the measuring window is within an allowable range; an elastic sealing cavity 61 is provided in the insulating base 6, the elastic sealing cavity 61 can be made of rubber or silicone material, and the elastic sealing cavity 61 is filled with insulating powder 62. In actual implementation, the insulating powder 62 can be configured as glass fiber powder, and the insulating base 6 is also provided with a The thermocouple can pierce the elastic sealing cavity 61 through the temperature measuring hole 10 and contact the heated plate 5. In actual implementation, a puncture hole with a diameter much smaller than that of the thermocouple can be opened on the elastic sealing cavity 61. Due to the material properties of the elastic sealing cavity 61 itself, after the thermocouple pierces the elastic sealing cavity 61, the hole wall of the puncture hole can be tightly attached to the thermocouple due to its own elastic deformation. At the same time, the thermal insulation powder 62 in the elastic sealing cavity 61 is more compacted under the pressure of the thermocouple, which means that the thermal insulation powder 62 can also be tightly attached to the thermocouple. Of course, since the thermal insulation powder 62 is compressed, the cavity wall of the elastic sealing cavity 61 will also be compressed by the thermal insulation powder 62 to undergo a certain elastic deformation.After the temperature measurement is completed, the thermocouple is taken out, and the puncture hole of the elastic sealing cavity 61 returns to its original shape under the action of elastic deformation, and the internal thermal insulation powder 62 is compressed under the elastic action of the cavity wall of the elastic sealing cavity 61, prompting the thermal insulation powder 62 to flow into the hole formed by the thermocouple, which means that under the elastic action of the elastic sealing cavity 61, the thermal insulation powder 62 can be self-filled, thereby providing better thermal insulation for the heated plate 5, avoiding heat loss of the heated plate 5, and ensuring that the thermal boundary of the coolant in the narrow slit channel 7 is basically consistent with the actual working conditions. In the normal viewing angle of the plate surface of the heated plate 5, multiple temperature measuring holes 10 are arranged at intervals to perform multi-point temperature measurement of the heated plate 5, which is conducive to analyzing the temperature distribution of the heated plate 5 under working conditions. Among them, the extension direction of the temperature measuring hole 10 can be unlimited, such as a straight line, a broken line, a curve or a combination of any two / three of the above. In order to reduce the temperature measuring hole The length of the temperature measuring hole 10 in its extension direction can be a straight line, wherein the extension direction of the temperature measuring hole 10 can be perpendicular to the plate surface of the heated plate 5 or form an angle. In actual implementation, it is preferred to set the extension direction of the temperature measuring hole 10 to be perpendicular to the plate surface of the heated plate 5, thereby ensuring that the length of the temperature measuring hole 10 in the extension direction is sufficiently short, which can facilitate the temperature measurement of the heated plate 5 from the temperature measuring hole 10. When the temperature measuring hole 10 is not working, it can be isolated. The shorter temperature measuring hole 10 can ensure that there is less heat exchange medium, such as air, inside in the isolated state, thereby reducing its impact on the local temperature of the heated plate 5 during the test. The cross-sectional shape of the temperature measuring hole 10 is not limited, such as triangle, rectangle, square, circle, heart, star or other special shapes. In actual implementation, the temperature measuring hole 10 can be set as a circular straight hole.

[0052] The cover body 4 has a circulation groove, and the cover body 4 is connected to the insulating base 6 so that the insulating base 6 seals the circulation groove to form a narrow slit channel 7, and the heated plate 5 is located in the narrow slit channel 7, that is, for the cover body 4 and the heated plate 5, the heated plate 5 can be placed in the circulation groove; the specific form of the circulation groove can be not limited, it can be a closed groove body on the cover body 4, that is, there is only one groove, or it can be an open groove body, that is, the circulation groove can pass through the cover body 4 to form two / three grooves; in actual implementation, the circulation groove can be set as a closed groove body, so that after the cover body 4 is connected to the insulating base 6, the insulating base 6 can easily seal the circulation groove through the working surface to form a narrow slit channel 7. Of course, in other embodiments, if the circulation groove is set as an open groove body, then after the cover body 4 is connected to the insulating base 6, the other grooves can be sealed separately or the other grooves can be connected to it. Other components are sealed and connected; the specific shape of the circulation groove is not limited, such as triangle, rectangle, square, circle or other special shapes; since a narrow slit channel 7 for the medium to flow is formed between the circulation groove and the insulating base 6, it is preferred to set the circulation groove to a trough shape with a certain length, such as a rectangular trough body, a square trough body, a prismatic trough body, and preferably, the circulation groove is set to a rectangular trough body or a square trough body, which means that from the perspective of the length direction of the circulation groove, the outline shape of the circulation groove is square or rectangular, wherein, when the circulation groove is set to a rectangular trough body or a square trough body, its extension direction can be a straight line or a curve. In actual implementation, the extension direction of the circulation groove can be set to a straight line to ensure that the medium has a stable flow state in the narrow slit channel 7. In other embodiments, as needed, the extension direction of the circulation groove can also be set to a curve or a combination of a curve and a straight line. When the circulation groove is set as a rectangular groove body or a square groove body, the heated plate 5 can be set as a rectangular plate body, that is, the thickness of the heated plate 5 is uniform except for the position of the vacuum bubble portion. At this time, the overall shape of the narrow slit channel 7 formed by the circulation groove and the insulating base 6 is a rectangular parallelepiped, which is conducive to the centering of the heated plate 5 in the narrow slit channel 7, ensuring that the heat can be evenly diffused in the narrow slit channel 7, and ensuring that the medium is evenly heated in the flow direction; the transmittance of the heated plate 5 is configured to be not less than 98%, that is, the medium in the narrow slit channel 7 can be visualized from the outside of the cover body 4.

[0053] The medium introduction member 1 is connected to one end of the narrow slit channel 7. When the circulation slot is configured as a closed slot, the medium introduction member 1 can pass through the insulating base 6 to connect with the narrow slit channel 7, and the medium introduction member 1 is sealed to the insulating base 6. When the circulation slot is configured as an open slot, the medium introduction member 1 can be directly sealed to the unsealed slot in the circulation slot. The medium introduction member 1 is generally used for injecting coolant.

[0054] The medium outlet 2 is connected to the other end of the narrow slit channel 7; when the circulation groove is set as a closed groove body, the medium outlet 2 can pass through the insulating base 6 to communicate with the narrow slit channel 7, and the medium outlet 2 is sealed to the insulating base 6; when the circulation groove is set as an open groove body, the medium outlet 2 can be directly sealed to the unclosed slot in the circulation groove.

[0055] The two conductive members 8 are respectively connected to the two ends of the heated plate 5. The conductive members 8 can be configured as copper bars, aluminum bars, stainless steel bars, zinc alloy bars, copper alloy bars, plastic conductive bars, etc. In actual implementation, the two conductive members 8 can be the same or different. Preferably, the two conductive members 8 can be configured as copper bars. Copper bars have excellent electrical conductivity, can reduce heat loss, and have good mechanical strength, corrosion resistance, high flexibility and good welding performance; the vacuum bubble portion is located between the two conductive members 8, that is, when the heated plate 5 is set to a rectangular plate body, the two conductive members 8 can be connected at both ends of the heated plate 5 in the longitudinal direction, and in the longitudinal direction of the heated plate 5, the vacuum bubble portion can be located in the middle position of the two conductive members 8. Of course, in other embodiments, the vacuum bubble portion can also be located at other positions between the two conductive members 8.

[0056] The first measuring device 13 is located on one side of the insulating base 6 to facilitate measurement of the heated plate 5. Specifically, the first measuring device 13 can measure the temperature of the corresponding position of the vacuum bubble portion on the heated plate 5 through the measuring window. The first measuring device 13 can be a contact measurement or a non-contact measurement. In actual implementation, the first measuring device 13 can be configured as an infrared thermal imager.

[0057] The second measuring device 14 is located on one side of the cover 4 to facilitate measurement of the medium in the narrow slit channel 7. The second measuring device 14 is a non-contact measurement. The second measuring device 14 is equipped with a laser 15, which can emit laser into the narrow slit channel 7 through the laser 15, so as to facilitate the second measuring device 14 to measure the medium; in actual implementation, the second measuring device 14 can be configured as a high-speed camera or a cross-frame camera, and a sheet of light is injected into the narrow slit channel 7 through the laser 15 to facilitate the second measuring device 14 to visualize the medium in the narrow slit channel 7.

[0058] The embodiment of the present application provides a dispersion type fuel element surface bubbling simulation measurement system, the vacuum bubble portion on the heated plate 5 can simulate the structural state of the dispersion type fuel element under bubbling conditions, after connecting the two conductive parts 8 to the power supply and connecting the medium inlet part 1 and the medium outlet part 2 to the medium circulation system, the heated plate 5 is electrically conductive to generate heat, thereby achieving a temperature increase, due to the thermal insulation effect of the thermal insulation base 6, most of the heat of the heated plate 5 is dissipated unilaterally to the narrow slit channel 7 to heat the medium in the narrow slit channel 7, thereby simulating the working state of the fluid in the dispersion type fuel element, and the first measuring device 13 can simulate the temperature of the corresponding position of the vacuum bubble portion on the heated plate 5 through the measuring window. The temperature field at the corresponding position of the vacuum bubble on the heated plate 5 is obtained by real-time measurement, and the temperature measuring hole 10 can be used to perform multi-point measurement on the heated plate 5 as needed to obtain the approximate temperature field distribution on the heated plate 5. The measurement values ​​between the temperature measuring hole 10 and the first measuring device 13 are also calibrated with each other. The second measuring device 14, with the assistance of the laser 15, can clearly visualize the fluid in the narrow channel 7. For example, by adding tracer particles to the fluid, the tracer particles will reflect the laser under the irradiation of the laser, and the particle displacement image can be captured by a cross-frame camera or a high-speed camera to obtain parameters such as the medium velocity field, thereby providing technical support for the precise formulation of thermal hydraulic design and safety standards of dispersed fuel elements.

[0059] Compared with the existing three-dimensional numerical simulation method, the dispersed fuel element surface bubble simulation measurement system provided in the embodiment of the present application can perform direct measurement, has relatively less calculation amount, is relatively more convenient to implement, and the data is more intuitive and easier to obtain, and the measurement results are quite credible.

[0060] In some optional embodiments, the dispersed fuel element surface bubble simulation measurement system can also be configured with a synchronizer 16, and the first measuring device 13 and the second measuring device 14 are respectively connected to the synchronizer 16, so that the measurement frequency, measurement period, etc. of the first measuring device 13 and the second measuring device 14 can be controlled by the synchronizer 16.

[0061] There are various ways of sealing the connection between the cover body 4 and the insulating base 6, for example, adhesive sealing, welding sealing, magnetic sealing, and threaded sealing can be used. Taking into account the maintainability of the entire device, in some optional embodiments, the cover body 4 is sealed with the insulating base 6 through a static sealing ring. The static sealing ring can be configured as a rubber sealing ring, a metal sealing ring, a polytetrafluoroethylene sealing ring, a graphite sealing ring, etc. In actual implementation, a suitable static sealing ring can be selected according to the thermal conductivity of the cover body 4. For example, if the thermal conductivity of the cover body 4 is low, a static sealing ring with average heat resistance, such as a rubber sealing ring, can be selected. When the thermal conductivity of the cover body 4 is high, a static sealing ring with high heat resistance, such as a graphite sealing ring, can be selected. In actual implementation, it is usually expected that the thermal conductivity of the cover body 4 is low. In order to avoid a large amount of heat loss in the narrow channel 7, that is, in the working state, the temperature of the cover body 4 will not be too high, the static sealing ring can be configured as a low-cost static sealing ring such as a rubber sealing ring; wherein, the static sealing ring is arranged around the circulation groove, and the shape of the static sealing ring can be not limited. For example, the static sealing ring can be rectangular, circular, triangular, diamond-shaped, etc., and can be specifically designed according to the adaptability of the notch of the circulation groove to avoid a large narrow space after the cover body 4 is connected to the insulating base 6; for example, when the circulation groove is a rectangular groove body, its notch is rectangular, and the static sealing ring can be configured as a rectangle. Of course, in other embodiments, according to needs, such as different installation conditions and different processing accuracy, the shape of the static sealing ring can also be other special shapes.

[0062] After the heated plate 5 is connected to the insulating base 6, we prefer that the heated plate 5 has a single heat dissipation area in order to control the heat dissipation direction of the heated plate 5, for example, one of the plate surfaces of the heated plate 5 is in the narrow slit channel 7, while the other surfaces are relatively isolated from the narrow slit channel 7, so that the heat of the heated plate 5 can basically be dissipated from one of the plate surfaces of the heated plate 5 to the narrow slit channel 7. Therefore, in some optional embodiments, a mounting sink is constructed on the working surface of the insulating base 6, and the heated plate 5 is connected to the mounting sink and one of the plate surfaces is flush with the working surface. As a result, the other surfaces of the heated plate 5 are in contact with the insulating base 6, and the heat dissipation area of ​​the heated plate 5 in the narrow slit channel 7 is reduced, that is, the plate surface with the vacuum bubble portion serves as the heat dissipation surface. In this way, the heat dissipation direction of the heated plate 5 is certain, which is conducive to the analysis of the heat dissipation characteristics of the heated plate 5, and the prediction of the heat distribution in the narrow slit channel 7, and can provide a certain theoretical basis for the experimental results.

[0063] The diffusion-type fuel element surface bubbling simulation measurement system provided in the embodiment of the present application realizes the external placement of the temperature measuring element (i.e., thermocouple). Compared with the existing concept of placing the temperature measuring element inside, the temperature measuring element in the present application does not have to be in a high-temperature working environment for a long time, which is conducive to ensuring the service life and measurement accuracy of the temperature measuring element; and the present application can conveniently use temperature measuring elements of different precisions to measure the heated plate 5 to meet various test requirements during the test process, and has relatively good applicability; after the measurement is completed, the elastic sealing cavity 61 can return to its original state under the elastic action of its own elasticity, and under the elastic action of the elastic sealing cavity 61, the internal insulation powder 62 completes self-filling at the same time, which can prevent heat loss from the heated plate 5 in a non-measurement environment, ensure that the thermal boundary of the coolant in the narrow slit channel 7 is basically consistent with the actual working conditions, and thereby ensure the accuracy of the test results.

[0064] The connection between the heated plate 5 and the insulating base 6 can be unlimited, as long as it is ensured that the heated plate 5 can be fitted with the insulating base 6 surface to achieve a better insulation effect. However, due to the influence of processing accuracy, there may be a certain gap between the heated plate 5 and the insulating base 6. If the gap is a slit connected to the narrow slit channel 7, it may have a certain impact on the temperature of the local medium in the narrow slit channel 7, which will be detrimental to the detailed study of the heat transfer characteristics of the local medium in the narrow slit channel 7. Therefore, in some optional embodiments, the heated plate 5 and the inner wall of the mounting sink are connected by filling with sealant. The sealant can be a relatively heat-resistant sealant to prevent deformation due to excessive temperature and affect the sealing effect between the heated plate 5 and the sealant. It can be configured as silicone sealant, polyurethane sealant, fluororubber sealant, polytetrafluoroethylene sealant, high-temperature silicate sealant, etc.

[0065] In some optional embodiments, the cover 4 is configured as optical quartz glass. Optical quartz glass has good light transmittance performance and low thermal conductivity, which can reduce heat loss of the medium in the narrow slit channel 7.

[0066] During the electrical conduction of the heated plate 5, it is preferred that the current have a good effective power, that is, the current essentially only performs work on the heated plate 5. Therefore, in some optional embodiments, the insulating base 6 is configured as an insulator, thereby greatly reducing power loss and ensuring electrical safety during the test. Preferably, the insulating base 6 can be configured as a resin. In other embodiments, the material used for the insulating base 6 can also be configured as a ceramic material, a fiber-reinforced ceramic-based material, a graphene material, etc. as needed.

[0067] The conductive member 8 is typically connected to other devices requiring electrical conductivity by welding. The heated plate 5 in the embodiment of the present application has a relatively high temperature during operation, so the weld between the conductive member 8 and the heated plate 5 should have a certain degree of heat resistance. Therefore, in some optional embodiments, the conductive member 8 is connected to the heated plate 5 by silver brazing. Silver has a smaller thermal expansion coefficient than copper, which means that when the temperature changes, the thermal stress generated at the silver brazing connection point is relatively small, which helps reduce the risk of loosening the connection. Silver also has good corrosion resistance, especially in high-temperature environments, which helps extend the service life of the welded joint and ensure the electrical conductivity of the conductive member 8 and the heated plate 5.

[0068] In some optional embodiments, the dispersed fuel element surface bubbling simulation measurement system further includes a pressure measuring pipe 12, which is connected to the narrow slit channel 7. In actual implementation, the pressure measuring pipe 12 passes through the insulating base 6 and is connected to the narrow slit channel 7. The number of pressure measuring pipes 12 can be configured to be two. In the flow direction of the medium, the two pressure measuring pipes 12 are respectively located on both sides of the vacuum bubble. Preferably, the two pressure measuring pipes 12 are respectively arranged near the medium inlet 1 and the medium outlet 2. Through the provision of the pressure measuring pipes 12, the medium pressure in the narrow slit channel 7 can be measured, and the changing characteristics of the medium pressure on both sides of the vacuum bubble can be obtained, which is conducive to studying the impact of the vacuum bubble on the medium pressure under the heat generation state.

[0069] In some optional embodiments, the medium inlet 1 and / or the medium outlet 2 are equipped with a temperature measuring pipe 11. In actual implementation, the temperature measuring pipe 11 can be configured on both the medium inlet 1 and the medium outlet 2. The provision of the temperature measuring pipe 11 can conveniently measure / monitor the medium temperature before the medium enters the narrow slit channel 7 and after the medium flows out of the narrow slit channel 7, which can bring convenience to the measurement process and facilitate the acquisition of the dynamic change characteristics of the medium temperature under long-term operation.

[0070] In some optional embodiments, the dispersed fuel element surface bubble simulation measurement system also includes a first pressure block 9 and a second pressure block 3 arranged at intervals, and the first pressure block 9 is connected to the second pressure block 3, wherein the first pressure block 9 abuts against the base, and the second pressure block 3 abuts against the cover body 4.

[0071] In the embodiment of the present application, by setting the first pressure-bearing block 9 and the second pressure-bearing block 3, the cover body 4 and the insulating base 6 can be pressed together, thereby ensuring the stability of the sealing performance between the cover body 4 and the insulating base 6. The first pressure-bearing block 9 and the second pressure-bearing block 3 can both be constructed as a rectangular parallelepiped, the first pressure-bearing block 9 can form a covering on the insulating base 6, and the second pressure-bearing block 3 can form a covering on the cover body 4. An observation window can be provided on the second pressure-bearing block 3 to facilitate the second measuring device 14 to perform visual measurement of the medium in the narrow slit channel 7. In the normal direction of the plate surface of the heated plate 5, the vacuum bubble portion is located within the range encompassed by the observation window, and the first pressure-bearing block 9 and the second pressure-bearing block 3 can be fastened together by bolts. Among them, the temperature measuring pipe 11, the conductive part 8, the pressure measuring pipe 12, the medium inlet 1 and the medium outlet 2 can all pass through the first pressure-bearing block 9 and the insulating base 6 in sequence to communicate with the narrow slit channel 7 or connect with the heated plate 5.

[0072] In some optional embodiments, see Figure 5 The heated plate includes a bubble plate 51, a heating plate 52 and an insulating layer 53; the bubble plate 51 is formed with a groove through a casting process; the heating plate 52 and the bubble plate 51 are arranged in parallel and spaced apart; the insulating layer 53 is located between the bubble plate 51 and the heating plate 52, and the insulating layer 53 is connected to the heating plate 52. The insulating layer 53 is connected to the bubble plate 51 through vacuum diffusion welding to enclose a vacuum bubble portion with the groove on the bubble plate 51.

[0073] When the heated plate provided in the present application is used in an experimental device for simulating the heat transfer characteristics under the condition of bubbling on the surface of a diffuse fuel element, since the heating plate 52 relies on electricity to generate heat to simulate the heating of the diffuse fuel element, through the setting of the insulating layer 53, the current only passes through the heating plate 52 and does not pass through the bubbling plate 51, thereby truly simulating the heat source distribution in the prototype fuel element. It can avoid the situation where the self-heating of the bubbling plate 51 affects the temperature field near the vacuum bubble portion, that is, it reduces the influencing factors of the temperature field near the vacuum bubble portion, which is beneficial to subsequent theoretical analysis and ensures the accuracy and credibility of the experimental results; and the insulating layer 53 is connected to the bubbling plate 51 by vacuum diffusion welding, and the connecting part has high temperature resistance and is suitable for the bubbling temperature environment on the surface of the diffuse fuel element.

[0074] In actual implementation, the bubble plate 51 is configured as an Inconel625 plate, so that the thermal conductivity of the bubble plate 51 can be close to the parameters of the zirconium alloy cladding in the dispersed fuel element, and the thickness of the bubble plate 51 is configured to be no more than 1 / 10 of the thickness of the heating plate 52; the portion of the heating plate 52 used for conduction is configured as an S32168 plate to ensure better resistance to intergranular corrosion and high temperature strength, wherein the entire heating plate 52 can be configured as an S32168 plate; the insulating layer 53 can be formed by coating the surface of the heating plate 52 with aluminum nitride ceramic using a PVD process, and the insulating layer 53 can be formed by coating the surface of the heating plate 52 with aluminum nitride ceramic. The thickness of layer 53 is 30 to 50 μm so as to not exceed 1 / 10 of the thickness of the blister plate 51, thereby achieving effective insulation under the operating conditions of the maximum voltage of 50 V in the experiment; the resistivity of the blister plate is much higher than the resistivity of the heating plate. With this arrangement, if cracks appear in the insulating layer 53 during the diffusion welding process or during use, the heat generated by the blister plate 51 will not exceed 5% of the total heat generated by electrical conduction. The influence of the heat generated by the blister plate 51 on the temperature field of the vacuum bubble portion is within an acceptable range, so that the experimental device has a certain ability to resist abnormalities, thereby ensuring the success rate of the experiment.

[0075] In a second aspect, embodiments of the present application provide a method for simulating and measuring bubbling on the surface of a dispersed fuel element, which is implemented based on the system for simulating and measuring bubbling on the surface of a dispersed fuel element described in the first aspect and includes the following contents:

[0076] S1. Provide a medium so that the medium circulates in the narrow slit channel 7.

[0077] During actual implementation, the medium inlet 1 and the medium outlet 2 are respectively connected to the medium circulation system.

[0078] S2. Provide power to make the heated plate 5 electrically conductive.

[0079] That is, the two conductive members 8 are respectively connected to the power supply / electrical system.

[0080] S3. Add tracer particles to the medium.

[0081] S4. Adjust the laser 15 so that the emission direction of the laser 15 coincides with the flow direction of the medium.

[0082] The tracer particles in the medium can reflect light and output visual signals under the irradiation of laser.

[0083] S5 , start the first measuring device 13 and the second measuring device 14 to measure the heated plate 5 and the medium.

[0084] Among them, the first measuring device 13 can be configured as an infrared thermal imager, and the second measuring device 14 can be configured as a high-speed camera or a cross-frame camera; before starting the second measuring device 14, the second measuring device 14 is first adjusted so that its shooting direction is perpendicular to the surface of the heated plate 5 to avoid unnecessary measurement errors caused by refraction of the light path.

[0085] During actual implementation, a data acquisition system can also be provided. The data acquisition system can be configured as a computer, an industrial computer, etc. The data acquisition system is used to collect parameters measured by the first measuring device 13 and the second measuring device 14. The data acquisition system is also used to collect the temperature parameters and pressure parameters of the medium at the temperature measuring pipe 11 and the pressure measuring pipe 12.

[0086] The above is an explanation of the implementation mode of the present application by specific specific embodiments. Those skilled in the art can easily understand other advantages and effects of the present application from the contents disclosed in this specification. Although the description of the present application will be introduced in conjunction with some embodiments, this does not mean that the features of this application are limited to the implementation mode. On the contrary, the purpose of introducing the application in conjunction with the implementation mode is to cover other options or modifications that may be extended based on the claims of the present application. In order to provide an in-depth understanding of the present application, the above description contains many specific details. The present application can also be implemented without using these details. In addition, in order to avoid confusion or blurring the focus of the present application, some specific details will be omitted in the description. It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other unless there is a conflict.

[0087] It should be noted that in the description of the application, similar reference numerals and letters in different drawings represent similar items, therefore, once an item is defined in one drawing, it is not necessary to further define and explain it in the subsequent drawings. In the description of the present application, it should be explained that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer" and the like indicate the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the indicated device or element must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first", "second" are only for the purpose of description, and cannot be understood as indicating or implying relative importance. In the description of the present application, it should be explained that unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connection" should be understood broadly, for example, it can be fixed connection, or detachable connection, or integral connection; it can be mechanical connection, or electrical connection; it can be direct connection, or indirect connection through intermediate medium, or internal communication of two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0088] Obviously, those skilled in the art can make various modifications and variations to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalent technologies, the present application also intends to include these modifications and variations.

Claims

1. A dispersion type fuel element surface foaming simulation measurement system, characterized in that: include: A heated plate (5) capable of electrical conduction, wherein one plate surface of the heated plate (5) has a vacuum bubble portion; an insulating base (6), the heated plate (5) being connected to a working surface of the insulating base (6), and the insulating base (6) having a measuring window corresponding to the position of the vacuum bubble portion and penetrating the insulating base (6); A cover body (4), the cover body (4) having a flow groove, the cover body (4) being connected to the heat-insulating base (6) so that the heat-insulating base (6) seals the flow groove to form a narrow slit channel (7), the heated plate (5) being located in the narrow slit channel (7), and the light transmittance of the cover body (4) being configured to be not less than 98%; A medium introduction member (1), the medium introduction member (1) being in communication with one end of the narrow slit channel (7); a medium outlet (2), the medium outlet (2) being in communication with the other end of the narrow slit channel (7); Conductive members (8), two of the conductive members (8) are respectively connected to two ends of the heated plate (5); a first measuring device (13), the first measuring device (13) being located on one side of the heat-insulating base (6) for measuring the heated plate (5) through the measuring window; A second measuring device (14) is located on one side of the cover (4) to measure the medium in the cover (4), and the second measuring device (14) is equipped with a laser (15).

2. The dispersion type fuel element surface bubbling simulation measurement system according to claim 1, characterized in that: The first measuring device (13) is configured as an infrared thermal imager.

3. The system for simulating and measuring the surface bubbling of a dispersed fuel element according to claim 1, characterized in that: The second measuring device (14) is configured as a high-speed camera or a cross-frame camera.

4. The system for simulating and measuring the surface bubbling of a dispersed fuel element according to claim 1, wherein: The invention also comprises a synchronizer (16), wherein the first measuring device (13) and the second measuring device (14) are respectively connected to the synchronizer (16).

5. The dispersion type fuel element surface bubbling simulation measurement system according to claim 1, characterized in that: The cover body (4) is sealed to the thermal insulation base (6) via a static sealing ring, wherein the static sealing ring is arranged around the flow groove.

6. The dispersion type fuel element surface bubbling simulation measurement system according to claim 1 or 5, characterized in that: A mounting sink is constructed on the working surface of the heat-insulating base (6), the heated plate (5) is connected to the mounting sink and one of the plate surfaces is flush with the working surface.

7. The system for simulating and measuring the surface bubbling of a dispersed fuel element according to claim 6, characterized in that: The heated plate (5) is connected to the inner wall of the mounting sink by filling with sealant.

8. The system for simulating and measuring the surface bubbling of a dispersed fuel element according to claim 1, characterized in that: The cover (4) is configured as optical quartz glass.

9. The system for simulating and measuring the surface bubbling of a dispersed fuel element according to claim 1, characterized in that: The insulating base (6) is configured as an insulator.

10. The system for simulating and measuring the surface bubbling of a dispersed fuel element according to claim 9, characterized in that: The heat-insulating base (6) is configured as a resin body.

11. The dispersion type fuel element surface bubbling simulation measurement system according to claim 1, characterized in that: The conductive member (8) is connected to the heated plate (5) by silver brazing.

12. The system for simulating and measuring the surface bubbling of a dispersed fuel element according to claim 1, characterized in that: An elastic sealing cavity (61) is provided in the insulating base (6), and the elastic sealing cavity (61) is filled with insulating powder (62). A temperature measuring hole (10) is also provided on the insulating base (6), so that a thermocouple can pierce the elastic sealing cavity (61) through the temperature measuring hole (10) and contact the heated plate (5).

13. The system for simulating and measuring the surface bubbling of a dispersed fuel element according to claim 1, characterized in that: It also includes a pressure measuring pipe (12), and the pressure measuring pipe (12) is communicated with the narrow slit channel (7).

14. The system for simulating and measuring the surface bubbling of a dispersed fuel element according to claim 1, characterized in that: The medium inlet (1) and / or the medium outlet (2) are equipped with a temperature measuring connection pipe (11).

15. The system for simulating and measuring bubbling on the surface of a dispersed fuel element according to claim 1, characterized in that: The invention also includes a first pressure-bearing block (9) and a second pressure-bearing block (3) arranged at intervals, wherein the first pressure-bearing block (9) is connected to the second pressure-bearing block (3), wherein the first pressure-bearing block (9) abuts against the base, and the second pressure-bearing block (3) abuts against the cover body (4), and an observation window is provided on the second pressure-bearing block (3).

16. The system for simulating and measuring the surface bubbling of a dispersed fuel element according to claim 1, characterized in that: The heated plate (5) comprises: A foaming plate (51), wherein the foaming plate (51) is formed with grooves through a casting process; A heating plate (52), the heating plate (52) and the bubbling plate (51) are arranged in parallel and spaced apart from each other; An insulating layer (53), the insulating layer (53) is located between the blister plate (51) and the heating plate (52), the insulating layer (53) is connected to the heating plate (52), and the insulating layer (53) is connected to the blister plate (51) by vacuum diffusion welding to enclose a vacuum bubble portion with the groove on the blister plate (51).

17. A method for simulating and measuring foaming on the surface of a dispersed fuel element, implemented based on the system for simulating and measuring foaming on the surface of a dispersed fuel element according to claims 1 to 16, characterized in that: Includes the following: providing a medium so that the medium circulates in the narrow slit channel (7); Providing power to make the heated plate (5) electrically conductive; Adding tracer particles to the medium; Adjusting the laser (15) so that the emission direction of the laser (15) coincides with the flow direction of the medium; The first measuring device (13) and the second measuring device (14) are activated to measure the heated plate (5) and the medium.

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