Reactor fuel irradiation device

Abstract

The invention provides a reactor fuel irradiation device which comprises a device section and a test section, the device section is provided with a coolant conveying pipe, and the test section comprises an upper connector, an outer sleeve and a lower connector which are sequentially connected in the first direction; the upper joint extends into the coolant delivery pipe and is in clearance sealing connection with the coolant delivery pipe to form an annular space, the upper joint is provided with a first spacing layer communicated with the annular space along the circumferential direction, and a coolant in the annular space can enter the first spacing layer and is in a static stagnation state during a test, so that a first heat insulation structure is formed; a second spacing layer is arranged on the outer sleeve in the circumferential direction, one end of the second spacing layer is open, so that a coolant outside the outer sleeve can enter the second spacing layer and is in a static stagnation state, and a second heat insulation structure is formed; a third spacing layer is arranged on the lower connector in the circumferential direction, one end of the third spacing layer is open, a coolant outside the lower connector can enter the third spacing layer and is in a static stagnation state, and therefore a third heat insulation structure is formed.

Description

Technical Field

[0001] The present application belongs to the technical field of research reactor irradiation, and specifically relates to a reactor fuel irradiation device. Background Art

[0002] The performance of the fuel has a direct impact on the safety and economy of the reactor, and conducting fuel irradiation tests is a key step in fuel research and development and design. In this test, the measured power of the fuel can be calculated by measuring the inlet and outlet temperature, flow rate, and pressure difference of the coolant in the test fuel section of the fuel irradiation device. However, since the test fuel section of the fuel irradiation device is usually a scaled-down fuel, its heat generation in the pile is smaller than that of the prototype, resulting in a small difference in the inlet and outlet temperature of the coolant in the irradiation device. In this case, the measurement error of the temperature measuring element will greatly affect the test results, resulting in poor accuracy in the measured power. Summary of the invention

[0003] Therefore, the technical problem to be solved by the present application is to provide a fuel irradiation device with the reactor, which can increase the temperature rise of the coolant after passing through the test fuel section, thereby reducing the impact of measurement errors on the test results and improving the accuracy of power measurement.

[0004] In order to solve the above problems, the present application provides a fuel irradiation device for a reactor, comprising a device section and a test section, wherein the device section is provided with a coolant delivery pipe, and the test section comprises an upper joint, an outer sleeve and a lower joint connected in sequence along a first direction;

[0005] The upper joint extends into the coolant delivery pipe and is sealed and connected with the coolant delivery pipe gap to form an annular gap. The upper joint is provided with a first spacer layer connected to the annular gap along the circumferential direction. When the test is performed, the coolant in the annular gap can enter the first spacer layer and be in a static stagnant state, thereby forming a first thermal insulation structure;

[0006] The outer sleeve is provided with a second spacer layer along the circumferential direction, and one end of the second spacer layer is open, so that the coolant outside the outer sleeve can enter the second spacer layer and be in the static stagnant state, thereby forming a second heat insulation structure;

[0007] The lower joint is provided with a third spacer layer along the circumferential direction, and one end of the third spacer layer is open, so that the coolant outside the lower joint can enter the third spacer layer and be in the static stagnant state, thereby forming a third thermal insulation structure.

[0008] Optionally, a plurality of annular sealing teeth are provided on the outer peripheral surface of the upper joint at a position relative to the annular gap, the plurality of sealing teeth are arranged at intervals along the axial direction, and the tooth tops of the sealing teeth are in gap sealing cooperation with the inner wall of the coolant delivery pipe.

[0009] Optionally, a test fuel section, a resistance plug and a mixer are sequentially arranged in the outer sleeve along the first direction, the test fuel section is used to carry fuel core blocks, the fuel core blocks are used to exchange heat with the coolant passing through the test fuel section, the resistance plug is used to apply resistance to the coolant passing through the test fuel section, and the mixer is used to stir the coolant passing through the resistance plug.

[0010] Optionally, the test fuel segment includes a clamp block, which is a hollow structure to form a positioning cavity for accommodating the fuel core block, and the positioning cavity has at least two limiting parts to position at least two of the fuel core blocks, and at least two of the fuel core blocks are used to divide the limiting cavity into at least three rectangular flow channels, and at least three of the rectangular flow channels are used to pass the coolant.

[0011] Optionally, at least three of the rectangular flow channels include an inner flow channel located between two of the fuel core blocks and outer flow channels distributed on both sides of the inner flow channel, and the passage area of ​​the inner flow channel is larger than the passage area of ​​the outer flow channel.

[0012] Optionally, the test fuel section also includes a clamp plate, the clamp block is connected to the clamp plate, the clamp plate protrudes from the outer wall of the clamp block and cooperates with the inner wall of the outer sleeve to form an annular flow channel between the clamp block and the outer sleeve, and the annular flow channel is also used to pass the coolant.

[0013] Optionally, the resistance plug includes a blocking body axially arranged in the outer sleeve, one end of the blocking body is provided with a plurality of upper support columns circumferentially spaced apart, and the other end of the blocking body is provided with a plurality of lower support columns circumferentially spaced apart, and portions of the upper support columns and the lower support columns radially protrude from the outer wall of the blocking body and cooperate with the inner wall of the outer sleeve to form a resistance flow channel between the blocking body and the outer sleeve.

[0014] Optionally, a plurality of annular blocking teeth are provided on the outer peripheral surface of the blocking body at a position relative to the resistance flow channel, and the plurality of blocking teeth are arranged at equal intervals along the axial direction, and the sum of the spacing between two adjacent blocking teeth and the tooth width of a single blocking tooth is 10 mm, the tooth width of a single blocking tooth is 2 mm to 5 mm, and the tooth depth of a single blocking tooth is less than or equal to 3 mm.

[0015] Optionally, the mixer is a disc-shaped structure, the outer wall of the mixer cooperates with the outer sleeve, and the mixer is evenly distributed with a plurality of guide holes passing through the mixer, and the center lines of the plurality of guide holes intersect, and the intersection point is located on the first direction side of the mixer.

[0016] Optionally, an inclination angle of a center line of the guide hole relative to a center axis of the flow mixer is less than or equal to 10 degrees.

[0017] Beneficial Effects

[0018] The stack-based fuel irradiation device provided in the embodiment of the present invention optimizes the heat transfer path by setting the first thermal insulation structure, the second thermal insulation structure and the third thermal insulation structure, so that the coolant can fully absorb heat when flowing through the test fuel section, reducing the diffusion of heat to the surrounding unrelated areas, and achieving a greater increase in the temperature of the coolant after passing through the test fuel section, thereby reducing the impact of measurement errors on the test results and improving the accuracy of power measurement. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a schematic structural diagram of a reactor fuel irradiation device according to an optional embodiment of the present application;

[0020] Figure 2 This is a schematic structural diagram of an upper joint of an optional embodiment of the present application;

[0021] Figure 3 This is a schematic structural diagram of an outer sleeve of an optional embodiment of the present application;

[0022] Figure 4 This is a schematic structural diagram of a lower joint of an optional embodiment of the present application;

[0023] Figure 5 A cross-sectional view of a test fuel section of an alternative embodiment of the present application;

[0024] Figure 6 This is a schematic diagram of the structure of a resistance plug of an optional embodiment of the present application;

[0025] Figure 7 This is a schematic structural diagram of a plugging body according to an optional embodiment of the present application.

[0026] The reference numerals are:

[0027] 1. Upper joint; 11. First spacer layer; 12. Sealing teeth; 13. Positioning pin; 2. Outer sleeve; 21. Second spacer layer; 22. Exhaust port; 3. Lower joint; 31. Third spacer layer; 32. Exhaust hole; 33. Leakage trough; 4. Upper spacer; 5. Test fuel section; 51. Fuel core block; 52. Clamp block; 53. Clamp plate; 54. Inner flow channel; 55. Outer flow channel; 56. Annular flow channel; 6. Resistance plug; 61. Blocking body; 62. Upper support column; 63. Lower support column; 64. Flow blocking teeth; 7. Mixer; 71. Guide hole; 8. Coolant delivery pipe; 9. Annular gap; 10. Thermocouple measuring point. DETAILED DESCRIPTION

[0028] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0029] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0030] In this application, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0031] The preferred embodiments of the present invention are described below in conjunction with the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0032] See also Figures 1 to 7As shown, according to an embodiment of the present application, a fuel irradiation device with a reactor is provided, including a device section and a test section, the device section is provided with a coolant delivery pipe 8, and the test section includes an upper joint 1, an outer sleeve 2 and a lower joint 3 connected in sequence along a first direction; the upper joint 1 extends into the coolant delivery pipe 8 and is gap-sealed with the coolant delivery pipe 8 to form an annular gap 9, and the upper joint 1 is circumferentially provided with a first spacer layer 11 connected to the annular gap 9. When conducting a test, the coolant in the annular gap 9 can enter the first spacer layer 11 and be in a static stagnant state, thereby forming a first thermal insulation structure; the outer sleeve 2 is circumferentially provided with a second spacer layer 21, one end of the second spacer layer 21 is open, so that the coolant outside the outer sleeve 2 can enter the second spacer layer 21 and be in a static stagnant state, thereby forming a second thermal insulation structure; the lower joint 3 is circumferentially provided with a third spacer layer 31, one end of the third spacer layer 31 is open, so that the coolant outside the lower joint 3 can enter the third spacer layer 31 and be in a static stagnant state, thereby forming a third thermal insulation structure.

[0033] By setting the first thermal insulation structure, the heat above the test fuel segment 5 can be prevented from being transferred to other parts such as the coolant delivery pipe 8, reducing the heat loss above the test fuel segment 5, so that more heat can be retained on the path through which the coolant flows, thereby helping to increase the temperature increase of the coolant after passing through the test fuel segment 5. By setting the second thermal insulation structure, the heat can be prevented from being lost to the external environment of the outer sleeve 2, so that more of the heat generated by the test fuel segment 5 is absorbed by the coolant, improving the efficiency of the coolant absorbing heat, and thus increasing the temperature increase of the coolant after passing through the test fuel segment 5. By setting the third thermal insulation structure, the heat loss below the test fuel segment 5 can be prevented, ensuring that the heat generated by the test fuel segment 5 is mainly taken away by the coolant, increasing the heat absorption of the coolant, and providing a guarantee for the significant increase in the temperature of the coolant after passing through the test fuel segment 5. Furthermore, by providing the first thermal insulation structure, the second thermal insulation structure and the third thermal insulation structure, the heat transfer path is optimized, so that the coolant can fully absorb heat when flowing through the test fuel segment 5, reducing the diffusion of heat to the surrounding unrelated areas, and achieving a greater increase in the temperature of the coolant after passing through the test fuel segment 5, thereby reducing the impact of measurement errors on the test results and improving the accuracy of the measured power.

[0034] The coolant may be water, liquid metal, etc., which is not limited in the present application. In this embodiment, the reactor fuel irradiation device is used for a water-cooled research reactor, and the coolant is water for illustration.

[0035] Specifically, the reactor fuel irradiation device includes a device section and a test section. The device section is fixed to the upper part of the research reactor pressure vessel, the lower part of the device section is connected to the test section, the lower part of the test section is inserted into the lower grid partition of the core, and the test fuel section 5 in the test section is located in the active area of ​​the core.

[0036] The lower part of the device section and the test section are both immersed in the research reactor cooling water. Specifically, the cooling water first flows into the device from the water inlet set on the side of the lower part of the device section. Then, the cooling water continues to flow and enters the test section, playing a cooling role in the test section. After completing the cooling task, the cooling water finally flows out. During the whole process, the cooling water circulates continuously to ensure that the device can operate under stable temperature conditions and provide reliable cooling guarantee for the smooth progress of the test.

[0037] The lower part of the device section is provided with a coolant delivery pipe 8. In the specific operation process of this embodiment, the cooling water in the research reactor acts as a coolant, and the cooling water first reaches the lower part of the device section, and then enters the test section through the coolant delivery pipe 8.

[0038] Among them, the test section is composed of multiple parts, including an upper joint 1, an outer sleeve 2 and a lower joint 3 connected in sequence along a first direction. When the cooling water flows in the device, its path is to enter the test section through the coolant delivery pipe 8. First, the cooling water reaches the upper joint 1, and then flows from the upper joint 1 into the outer sleeve 2. In the outer sleeve 2, the cooling water performs heat exchange and other functions with related components in the test fuel section 5. After completing the process in the outer sleeve 2, the cooling water then flows to the lower joint 3, and finally flows out of the test section through the lower joint 3, and continues to circulate in the cooling system of the entire device. It should be noted that the first direction can be the direction of the device section toward the test section or the flow direction of the cooling water in the test section.

[0039] The upper joint 1 is provided with a first spacer layer 11 along the circumferential direction. The first spacer layer 11 is a central sandwich structure provided on the outer wall of the upper joint 1. During the test, the first spacer layer 11 can be automatically filled with cooling water. When the cooling water fills the first spacer layer 11, since only one end of the first spacer layer 11 is open, the cooling water in the first spacer layer 11 is in a relatively static state, thereby forming a dead water insulation zone.

[0040] Specifically, the upper joint 1 can be inserted into the coolant delivery pipe 8. The outer wall of the upper joint 1 and the inner wall of the coolant delivery pipe 8 are clearance-fitted to form an annular gap 9 between the outer wall of the upper joint 1 and the inner wall of the coolant delivery pipe 8. In the first spacer layer 11, an annular groove is radially opened at the position corresponding to the annular gap 9, and the annular groove faces the annular gap 9, so that the first spacer layer 11 can be interconnected with the annular gap 9. When the test is carried out, part of the cooling water inside the coolant delivery pipe 8 will flow into the outer sleeve 2 through the upper joint 1, and the other part will enter the annular gap 9. Since the first spacer layer 11 is connected to the annular gap 9 through the annular groove, the cooling water in the annular gap 9 can enter the first spacer layer 11 through the annular groove. When the cooling water in the annular gap 9 enters the first spacer layer 11 through the annular groove, since the first spacer layer 11 is open only at the annular groove, the cooling water cannot form an effective circulation flow in the first spacer layer 11 and can only be in a relatively static state, thereby effectively preventing the heat above the test fuel section 5 in the test section from being transferred to other parts such as the coolant delivery pipe 8.

[0041] The outer peripheral surface of the upper joint 1 is provided with a positioning pin 13, which can be a convex block protruding from the outer wall of the upper joint 1. When the upper joint 1 is inserted into the coolant delivery pipe 8, the positioning pin 13 can limit the movement range of the upper joint 1, ensuring that the upper joint 1 and the coolant delivery pipe 8 are accurately positioned when assembled and maintain a stable connection state.

[0042] The test fuel section 5 is located inside the outer casing 2 .

[0043] The outer sleeve 2 is provided with a second spacer layer 21 along the circumferential direction. The second spacer layer 21 is a central sandwich structure provided on the tube wall of the outer sleeve 2. During the test, the cooling water outside the outer sleeve 2 can automatically enter the second spacer layer 21. Since only one end of the second spacer layer 21 is open, the cooling water entering the second spacer layer 21 cannot form an effective circulation flow and can only be in a relatively static state, thereby forming another dead water insulation zone.

[0044] Specifically, the end of the second spacer layer 21 close to the upper joint 1 is open, and the end away from the upper joint 1 is closed, that is, the upper end of the second spacer layer 21 is open, and the lower end is closed. An annular exhaust port 22 is formed at the open end of the second spacer layer 21, and the annular exhaust port 22 faces the opposite direction of the first direction. It should be noted that the cooling water flow direction outside the outer sleeve 2 is also the opposite direction of the first direction.

[0045] Among them, when the cooling water flows in the reverse direction outside the outer sleeve 2 (i.e., flows in the opposite direction of the first direction), since the upper end of the second spacer layer 21 is open and the annular exhaust port 22 is also facing the opposite direction of the first direction. On the one hand, the cooling water can enter the second spacer layer 21 relatively smoothly, and because the lower end of the second spacer layer 21 is closed, the cooling water entering the second spacer layer 21 cannot form an effective circulation flow, and can only be in a relatively static state, thereby forming a stable dead water insulation zone, effectively preventing heat from being lost to the external environment of the outer sleeve 2, allowing the heat generated by the test fuel section 5 to be more absorbed by the cooling water, improving the efficiency of the cooling water absorbing heat, and then increasing the temperature increase of the cooling water after passing through the test fuel section 5; on the other hand, the setting of the annular exhaust port 22 can discharge the gas that may exist in the second spacer layer 21 during the process of the cooling water entering the second spacer layer 21, ensuring that the second spacer layer 21 can be fully filled with cooling water, so as to better play the role of heat insulation, further optimize the heat transfer performance of the entire fuel irradiation device with the stack, and provide reliable guarantee for the accurate conduct of the test.

[0046] Specifically, the cooling water outside the outer sleeve 2 is in a high-pressure state compared to the gas in the second spacer layer 21. When the cooling water enters the second spacer layer 21, due to the pressure difference, the internal gas can be quickly squeezed out and discharged to the external environment through the annular exhaust port 22. In this way, it is not only ensured that the second spacer layer 21 can be quickly filled with cooling water to form a stable dead water insulation zone, but also prevents the gas from accumulating in the second spacer layer 21 and affecting the insulation effect.

[0047] The lower joint 3 is provided with a third spacer layer 31 along the circumferential direction. The third spacer layer 31 is a central sandwich structure provided on the outer wall of the lower joint 3. During the test, the cooling water outside the lower joint 3 can automatically enter the third spacer layer 31. Since only one end of the third spacer layer 31 is open, the cooling water entering the third spacer layer 31 cannot form an effective circulation flow and can only be in a relatively static state, thereby forming another dead water insulation zone.

[0048] Specifically, the end of the third spacer layer 31 away from the outer sleeve 2 is open, and a water inlet is formed, and the water inlet faces the first direction. At the same time, the end of the third spacer layer 31 close to the outer sleeve 2 is radially provided with an exhaust hole 32. When the cooling water flows outside the lower joint 3, the flow direction of the cooling water is opposite to the first direction. During the test, when the cooling water flows in the reverse direction (i.e., flows in the opposite direction of the first direction) through the lower joint 3, since the water inlet of the third spacer layer 31 faces the first direction, under the action of pressure, the cooling water can smoothly enter the third spacer layer 31 from the water inlet. In the process of the cooling water entering the third spacer layer 31, the exhaust hole 32 opened at the end of the third spacer layer 31 close to the outer sleeve 2 can timely discharge the gas in the third spacer layer 31, ensuring that the third spacer layer 31 can be fully filled with cooling water to form an effective thermal insulation structure. As a result, it is beneficial for cooling water to enter the third spacer layer 31 to play an insulating role, prevent heat loss under the test fuel segment 5, ensure that the heat generated by the test fuel segment 5 is mainly taken away by the cooling water, increase the heat absorption of the cooling water, and provide a guarantee for the significant increase in the temperature of the cooling water after passing through the test fuel segment 5; it can also discharge gas in time to avoid gas accumulation affecting the insulation effect, further optimize the heat transfer performance of the stack fuel irradiation device, and improve the accuracy of the test results.

[0049] The lower joint 3 is also provided with a drainage groove 33 along the circumferential direction. The drainage groove 33 may be a rectangular groove or an arc groove provided on the outer circumferential surface of the lower joint 3, and the present application does not limit this.

[0050] Specifically, the leakage groove 33 is located on the outer peripheral surface of the lower joint 3 at a position relative to the lower grid partition of the core to ensure that the cooling water can flow smoothly through the leakage groove 33, and at the same time, it plays a role in leaking and reducing pressure, guiding the flow direction of cooling water, etc. when necessary.

[0051] In some possible embodiments disclosed in this application, Figure 2 As shown, a plurality of annular sealing teeth 12 are arranged at positions relative to the annular gap 9 on the outer peripheral surface of the upper joint 1, and the plurality of sealing teeth 12 are arranged at intervals along the axial direction, and the tooth tops of the sealing teeth 12 are in gap sealing cooperation with the inner wall of the coolant delivery pipe 8. Thus, a multiple sealing structure is formed, the viscous resistance is increased, and the leakage of cooling water from the annular gap 9 can be effectively avoided, thereby reducing the deviation between the actual flow rate and the designed flow rate, and providing a strong guarantee for improving the accuracy of the test results.

[0052] The annular gap 9 is a space formed by the upper joint 1 extending into the coolant delivery pipe 8 and being gap-sealedly connected with the coolant delivery pipe 8 .

[0053] Specifically, the length of the annular gap 9 is greater than 100 mm, so that the leakage path can be extended and the difficulty of leakage can be increased.

[0054] A plurality of sealing teeth 12 are arranged at intervals in the annular gap 9 along the central axis direction of the annular gap 9. When cooling water flows in the annular gap 9, the plurality of sealing teeth 12 can effectively prevent the cooling water from leaking to the outside of the annular gap 9.

[0055] Specifically, as one embodiment, a plurality of sealing teeth 12 are arranged at equal intervals, so that each sealing tooth 12 bears a relatively uniform sealing pressure, ensuring that the sealing effect of the entire annular gap 9 is relatively consistent; as another embodiment, a plurality of sealing teeth 12 are arranged at a gradual interval, which can adapt to the changes in the pressure and flow rate of the cooling water in the annular gap 9, so that the sealing effect is more stable within the entire annular gap 9.

[0056] In some possible embodiments disclosed in this application, Figure 1 As shown, a test fuel segment 5, a resistance plug 6 and a mixer 7 are sequentially arranged in the outer sleeve 2 along a first direction. The test fuel segment 5 is used to carry fuel core blocks 51, and the fuel core blocks 51 are used to exchange heat with the cooling water passing through the test fuel segment 5. The resistance plug 6 is used to apply resistance to the cooling water passing through the test fuel segment 5, and the mixer 7 is used to stir the cooling water passing through the resistance plug 6.

[0057] The first direction is the flow direction of the cooling water in the outer sleeve 2 .

[0058] Among them, a test fuel section 5 is provided in the outer sleeve 2, and the test fuel section 5 provides a fixed position and space for the fuel core block 51, so that the cooling water passing through the test fuel section 5 can fully contact with the fuel core block 51, and efficiently absorb the heat released by the fuel core block 51, thereby improving the heat exchange efficiency.

[0059] Among them, a resistance plug 6 is provided on the downstream side of the test fuel segment 5 along the flow direction. The resistance plug 6 can apply resistance to the cooling water passing through the test fuel segment 5, so that the flow rate of the cooling water in the test fuel segment 5 is reduced, the contact time between the cooling water and the fuel core block 51 is increased, the adequacy of heat exchange is improved, and the cooling water can absorb more heat.

[0060] Among them, a mixer 7 is arranged on the downstream side of the resistance plug 6 along the flow direction. The mixer 7 can stir the cooling water passing through the resistance plug 6, so that the cooling water can be quickly mixed and evenly mixed after flowing out of the test fuel section 5, avoiding the situation where the local temperature is too high or too low, and improving the accuracy of the test results.

[0061] Among them, an upper partition tube 4 is also provided in the outer sleeve 2, and the upper partition tube 4 is provided on the upstream side of the test fuel segment 5 along the flow path direction. It should be noted that by providing the upper partition tube 4, on the one hand, it can resist the various forces exerted on the device due to the flow of cooling water, temperature changes and the influence of the external environment, and enhance the stability of the structure; on the other hand, it can cut off the path of heat conduction from the test fuel segment 5 to the upper side, reduce heat loss, increase the temperature rise of the cooling water after passing through the test fuel segment 5, and improve the heat absorption efficiency of the cooling water.

[0062] In some possible embodiments disclosed in this application, Figure 5 As shown, the test fuel segment 5 includes a clamp block 52, which is a hollow structure to form a positioning cavity for accommodating a fuel core block 51. The positioning cavity has at least two limiting portions to position at least two fuel core blocks 51. The at least two fuel core blocks 51 are used to divide the limiting cavity into at least three rectangular flow channels, and the at least three rectangular flow channels are used to pass cooling water.

[0063] Among them, the clamp block 52 is axially arranged inside the outer sleeve 2. As an embodiment, the clamp block 52 is a split structure, and the clamp block 52 includes a first clamp body and a second clamp body. When installing the fuel pellet 51, the fuel pellet 51 can be placed on the first clamp body first, and then the second clamp body is connected to the first clamp body, so as to fix the fuel pellet 51 in the positioning cavity; as another embodiment, the clamp block 52 is an integral structure, and the clamp block 52 is integrally formed. When installing the fuel pellet 51, the fuel pellet 51 is placed in the positioning cavity of the clamp block 52, and it is ensured that the fuel pellet 51 is accurately in contact with the limiting part in the positioning cavity to achieve precise positioning. In this embodiment, the clamp block 52 is a split structure.

[0064] The positioning cavity may be a cylindrical cavity or a long strip cavity that passes through the clamp block 52 and can hold the fuel pellet 51 and allow cooling water to pass through, which is not limited in the present application.

[0065] The limiting part is located on the side wall of the positioning cavity, specifically, it is composed of two depressions on the side wall. When the fuel pellet 51 is placed in the positioning cavity, part of the surface of the fuel pellet 51 contacts the two depressions on the side wall, and the two depressions work together to limit the movement of the fuel pellet 51 in the positioning cavity, thereby ensuring that the fuel pellet 51 can be accurately placed in the predetermined position and will not be displaced unnecessarily during the operation of the fuel irradiation device.

[0066] In some specific examples, the fuel pellet 51 is cylindrical, and the two depressions on the side wall of the positioning cavity are two arc-shaped grooves, which fit the side surfaces of the fuel pellet 51 and restrict the horizontal movement of the fuel pellet 51 from different positions.

[0067] In other specific examples, the fuel pellet 51 is in the shape of an elongated strip, and the two depressions on the side wall of the positioning cavity are two rectangular grooves. The two rectangular grooves can fit tightly against the sides of the fuel pellet 51, limit the fuel pellet 51 from multiple directions, and effectively limit the movement of the fuel pellet 51 in the positioning cavity.

[0068] Specifically, in this embodiment, the fuel pellet 51 is in the shape of an elongated strip, and the limiting portions are two rectangular grooves on the side wall of the positioning cavity.

[0069] Among them, at least two limiting parts are arranged in the positioning cavity of the clamp block 52. The two rectangular grooves of each limiting part can fit closely to the sides of a long strip of fuel pellet 51, and limit the fuel pellet 51 from multiple directions to ensure the stability of the position of the fuel pellet 51 in the positioning cavity. At least two limiting parts work together to position at least two fuel pellets 51, so that multiple fuel pellets 51 can be arranged in order in the positioning cavity, and no unnecessary displacement will occur during the operation of the stack fuel irradiation device. When the cooling water flows through the positioning cavity, it can fully contact each fuel pellet 51 to carry out efficient heat exchange.

[0070] Specifically, taking the case where two limiting parts are provided as an example, two elongated fuel pellets 51 are positioned in the positioning cavity of the clamping block 52. Since the fuel pellets 51 are elongated, the two fuel pellets 51 and the inner wall of the positioning cavity jointly divide three rectangular flow channels. When the cooling water flows through the three rectangular flow channels, it can fully exchange heat with the fuel pellets 51.

[0071] In the above embodiment, the at least three rectangular flow channels include an inner flow channel 54 located between two fuel core blocks 51 and outer flow channels 55 distributed on both sides of the inner flow channel 54 . The passage area of ​​the inner flow channel 54 is larger than that of the outer flow channel 55 .

[0072] Specifically, the inner flow channel 54 is located in the middle of the two fuel pellets 51, and a larger passage area means that more cooling water can flow directly in this area. Since the main function of cooling water is to absorb the heat released by the fuel pellets 51, the larger passage area of ​​the inner flow channel 54 allows more cooling water to fully contact the opposite sides of the two fuel pellets 51. In this way, in the same time, the cooling water in the inner flow channel 54 can absorb more heat, improving the efficiency of heat exchange. On the other hand, a larger passage area will also affect the flow rate of cooling water in the inner flow channel 54. According to the principles of fluid mechanics, under the condition of a constant flow rate, the larger the flow area, the smaller the flow rate. Therefore, the flow rate of cooling water in the inner flow channel 54 is relatively slow. This increases the contact time between cooling water and fuel pellets 51, so that heat can be more effectively transferred from fuel pellets 51 to cooling water. As for the outer flow channel 55, although its passage area is small, it also plays an important role in the entire heat exchange process. The outer flow channel 55 is distributed on both sides of the inner flow channel 54, which can play a role in diverting cooling water. When the cooling water flows into the positioning cavity, part of the cooling water will enter the outer flow channel 55, thereby avoiding local overheating or overcooling caused by all the cooling water being concentrated in the inner flow channel 54. The cooling water in the outer flow channel 55 can cool the side of the fuel pellet 51, and together with the inner flow channel 54, realize all-round cooling of the fuel pellet 51.

[0073] In some possible embodiments disclosed in this application, Figure 1 and Figure 5 As shown, the test fuel section 5 also includes a clamp 53, the clamp block 52 is connected to the clamp 53, the clamp 53 protrudes from the outer wall of the clamp block 52 and cooperates with the inner wall of the outer sleeve 2 to form an annular flow channel 56 between the clamp block 52 and the outer sleeve 2, and the annular flow channel 56 is also used to pass cooling water.

[0074] Among them, taking the clamp block 52 as a split structure as an example, the clamp plate 53 is an annular structure, at least two clamp plates 53 are provided, and at least two clamp plates 53 are respectively sleeved on both ends of the clamp block 52 to lock the first clamp body, the second clamp body and the fuel core block 51, thereby ensuring that the fuel core block 51 is firmly wrapped in the positioning cavity of the clamp block 52 to prevent the fuel core block 51 from displacement.

[0075] Specifically, the clamping plate 53 is sleeved on the clamping block 52 and is in gap with the inner wall of the outer sleeve 2. Since the clamping plate 53 protrudes from the outer wall of the clamping block 52, there is a certain gap between the clamping block 52 and the inner wall of the outer sleeve 2, thereby forming an annular flow channel 56. In this way, a new flow path is provided for the cooling water, and the contact area between the cooling water and the test fuel segment 5 is increased, so that the cooling water can not only flow in the rectangular flow channel divided by the fuel core block 51 for heat exchange, but also flow in the annular flow channel 56 to contact the surfaces of the clamping block 52, the clamping plate 53 and other components, thereby absorbing the heat of the clamping block 52, the clamping plate 53 and other components, and reducing the heat loss to the external environment of the outer sleeve 2.

[0076] In some possible embodiments disclosed in this application, Figure 6 As shown, the resistance plug 6 includes a blocking body 61 axially arranged in the outer sleeve 2, a plurality of upper support columns 62 are circumferentially spaced apart at one end of the blocking body 61, and a plurality of lower support columns 63 are circumferentially spaced apart at the other end of the blocking body 61, and portions of the upper support columns 62 and the lower support columns 63 radially protrude from the outer wall of the blocking body 61 and cooperate with the inner wall of the outer sleeve 2 to form a resistance flow channel between the blocking body 61 and the outer sleeve 2.

[0077] By providing the upper support column 62 and the lower support column 63, the plugging body 61 can be fixed in the outer sleeve 2, providing a supporting force for the plugging body 61, and preventing the plugging body 61 from being displaced or deformed under the impact of the cooling water. By providing the plugging body 61 to occupy the space in the outer sleeve 2, a resistance is applied to the cooling water flowing out of the test fuel section 5, so that the flow rate of the cooling water is reduced when flowing through the test fuel section 5, and the contact time with the fuel pellets 51 is prolonged, so that there is more time to fully absorb the heat released by the fuel pellets 51, thereby improving the efficiency of heat exchange.

[0078] In some specific examples, the blocking body 61 is a columnar structure, specifically a cylindrical shape, with a smooth surface, tightly matched with the upper support column 62 and the lower support column 63, and can be stably placed in the outer sleeve 2 to provide reliable resistance for the flow of cooling water. The blocking body 61 of the columnar structure has a certain length in the axial direction, which can fully occupy the space in the outer sleeve 2, ensuring that the cooling water is effectively resisted when flowing through, thereby reducing the flow rate and increasing the heat exchange time.

[0079] In other specific examples, the blocking body 61 is a barrel-shaped structure, similar to an open barrel. The blocking body 61 of the barrel-shaped structure opens toward the test fuel section 5, thereby forming a mixed flow cavity. When the cooling water enters the mixed flow cavity and contacts the bottom of the barrel of the barrel-shaped structure, an upward reflux effect is generated, thereby achieving the mixing of the cooling water and improving the measurement accuracy of the average water temperature of the cooling water outlet of the test section.

[0080] There may be three upper support columns 62 and three lower support columns 63 , and the three upper support columns 62 and the three lower support columns 63 are evenly arranged along the circumferential direction of the blocking body 61 .

[0081] Specifically, the upper support column 62 and the lower support column 63 both extend in the radial direction, and both the upper support column 62 and the lower support column 63 partially protrude from the outer wall of the blocking body 61 in the radial direction and cooperate with the inner wall of the outer sleeve 2, so that there is a certain gap between the outer wall of the blocking body 61 and the inner wall of the outer sleeve 2, thereby forming a resistance flow channel.

[0082] In the above embodiment, a plurality of annular blocking teeth 64 are provided on the outer peripheral surface of the blocking body 61 at a position relative to the resistance flow channel, and the plurality of blocking teeth 64 are arranged at equal intervals along the axial direction. The sum of the spacing between two adjacent blocking teeth 64 and the tooth width of a single blocking tooth 64 is 10 mm, the tooth width of a single blocking tooth 64 is 2 mm to 5 mm, and the tooth depth of a single blocking tooth 64 is less than or equal to 3 mm.

[0083] The flow resistance to the cooling water is further increased by providing the blocking teeth 64 in the resistance flow channel, so that when the cooling water flows through the resistance flow channel, it not only has to overcome the resistance formed by the blocking body 61, but also has to flow around the blocking teeth 64. The effect of this multiple resistance further reduces the flow rate of the cooling water, thereby increasing the contact time between the cooling water and the fuel pellets 51 and the blocking body 61 itself, and improving the heat exchange efficiency.

[0084] The number of the baffle teeth 64 may be three, four or five, etc., which is not limited in the present application.

[0085] The flow blocking teeth 64 are substantially annular structures, and the annular flow blocking teeth 64 are arranged perpendicular to the outer peripheral surface of the blocking body 61 to form a stable resistance effect in the resistance flow channel.

[0086] Specifically, in this embodiment, the spacing distance between two adjacent blocking teeth 64 is preferably 7 mm, the tooth width of a single blocking tooth 64 is preferably 3 mm, and the tooth depth of a single blocking tooth 64 is preferably 2.7 mm.

[0087] In some possible embodiments disclosed in this application, Figure 7 As shown, the mixer 7 is a disc-shaped structure, the outer wall of the mixer 7 cooperates with the outer sleeve 2, and the mixer 7 is evenly distributed with a plurality of guide holes 71 penetrating the mixer 7. The center lines of the plurality of guide holes 71 intersect, and the intersection point is located on the first direction side of the mixer 7.

[0088] By providing the mixer 7, the flow direction of the cooling water can be changed, the cooling water in different areas can be mixed together, and the uniformity of heat exchange can be improved. Furthermore, the uniformly mixed cooling water can ensure that the water temperature at the cooling water outlet of the test section more accurately reflects the effect of the entire heat exchange process. The measurement error caused by local temperature differences is avoided, thereby improving the accuracy of the test results.

[0089] Among them, the outer diameter of the mixer 7 is adapted to the inner diameter of the outer sleeve 2, which can achieve a tight fit or a clearance fit, preventing the cooling water from directly flowing through the gap between the mixer 7 and the outer sleeve 2 without being stirred, thereby ensuring that the mixer 7 effectively treats the cooling water.

[0090] Among them, a plurality of guide holes 71 are evenly distributed on the plane of the flow mixer 7, so that the cooling water can enter the guide holes 71 from different positions, thereby achieving a more uniform stirring effect.

[0091] The guide hole 71 penetrates the flow mixer 7, so that the cooling water can flow from one side of the flow mixer 7 to the other side through the guide hole 71. When the cooling water passes through the guide hole 71, its flow direction will change due to the special arrangement of the guide hole 71.

[0092] Specifically, the center lines of several guide holes 71 intersect, and the intersection is located on the first direction side of the mixer 7. The first direction is the flow direction of the cooling water in the outer sleeve 2. The cooling water flowing out of different guide holes 71 will converge near the intersection, thereby producing a strong mixing effect. After the cooling water passes through the resistance plug 6, its flow rate and temperature may be uneven. Through the guidance and intersection of the guide holes 71, the cooling water can be quickly mixed and evenly mixed, avoiding the occurrence of local over-high or over-low temperatures, improving the uniformity and stability of heat exchange, and thus improving the performance of the entire fuel irradiation device and the accuracy of the test results.

[0093] It should be noted that a thermocouple measuring point 10 is provided on the first direction side of the flow mixer 7 , and the thermocouple measuring point 10 is located inside the lower joint 3 .

[0094] In the above embodiment, the inclination angle of the center line of the guide hole 71 relative to the central axis of the mixer 7 is less than or equal to 10 degrees. In this way, it can be ensured that the flow direction of the cooling water changes relatively smoothly when passing through the guide hole 71. This can avoid excessive turbulence of the water flow due to too large an inclination angle, reduce the instability factors of the water flow, and enable the cooling water to mix and flow in a relatively stable state. For example, the inclination angle of the center line of the guide hole 71 relative to the central axis of the mixer 7 is 2 degrees, or 4 degrees, or 6 degrees, or 8 degrees, or 10 degrees. It can be understood that the inclination angle of the center line of the guide hole 71 relative to the central axis of the mixer 7 can also be other values ​​other than the above values, as long as the inclination angle of the center line of the guide hole 71 relative to the central axis of the mixer 7 is less than or equal to 10 degrees.

[0095] It is easy for those skilled in the art to understand that, under the premise of no conflict, the above-mentioned advantageous methods can be freely combined and superimposed.

[0096] The above are only preferred embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present application shall be included in the protection scope of the present application. The above are only preferred implementations of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and variations can be made without departing from the technical principles of the present application, and these improvements and variations should also be regarded as the protection scope of the present application.

Claims

1. A fuel irradiation device, characterized in that: It comprises a device section and a test section, wherein the device section is provided with a coolant delivery pipe (8), and the test section comprises an upper joint (1), an outer sleeve (2), and a lower joint (3) which are sequentially connected along a first direction; The upper joint (1) extends into the coolant delivery pipe (8) and is gap-sealed with the coolant delivery pipe (8) to form an annular gap (9). The upper joint (1) is provided with a first spacer layer (11) in the circumferential direction and connected to the annular gap (9). When conducting a test, the coolant in the annular gap (9) can enter the first spacer layer (11) and be in a static stagnant state, thereby forming a first thermal insulation structure; The outer sleeve (2) is provided with a second spacer layer (21) along the circumferential direction, and one end of the second spacer layer (21) is open, so that the coolant outside the outer sleeve (2) can enter the second spacer layer (21) and be in the static stagnant state, thereby forming a second thermal insulation structure; The lower joint (3) is provided with a third spacer layer (31) along the circumferential direction, and one end of the third spacer layer (31) is open, so that the coolant outside the lower joint (3) can enter the third spacer layer (31) and be in the static stagnant state, thereby forming a third thermal insulation structure.

2. The reactor fuel irradiation device according to claim 1, characterized in that: A plurality of annular sealing teeth (12) are provided on the outer peripheral surface of the upper joint (1) at a position relative to the annular gap (9), the plurality of sealing teeth (12) are arranged at intervals along the axial direction, and the tooth tops of the sealing teeth (12) are in gap sealing cooperation with the inner wall of the coolant delivery pipe (8).

3. The reactor fuel irradiation device according to claim 1, characterized in that: A test fuel section (5), a resistance plug (6) and a mixer (7) are sequentially arranged in the outer sleeve (2) along the first direction; the test fuel section (5) is used to carry a fuel core block (51); the fuel core block (51) is used to exchange heat with the coolant passing through the test fuel section (5); the resistance plug (6) is used to apply resistance to the coolant passing through the test fuel section (5); and the mixer (7) is used to stir the coolant passing through the resistance plug (6).

4. The stack-mounted fuel irradiation device according to claim 3, characterized in that: The test fuel section (5) comprises a clamp block (52), the clamp block (52) being a hollow structure to form a positioning cavity for accommodating the fuel pellets (51), the positioning cavity having at least two limiting portions to position at least two of the fuel pellets (51), the at least two of the fuel pellets (51) being used to divide the limiting cavity into at least three rectangular flow channels, and the at least three of the rectangular flow channels being used to pass the coolant.

5. The stack-mounted fuel irradiation device according to claim 4, characterized in that: At least three of the rectangular flow channels include an inner flow channel (54) located between two of the fuel core blocks (51) and outer flow channels (55) distributed on both sides of the inner flow channel (54), and the passage area of ​​the inner flow channel (54) is larger than the passage area of ​​the outer flow channel (55).

6. The stack-mounted fuel irradiation device according to claim 4, characterized in that: The test fuel section (5) further comprises a clamping plate (53), the clamping block (52) being connected to the clamping plate (53), the clamping plate (53) protruding from the outer wall of the clamping block (52) and cooperating with the inner wall of the outer sleeve (2) so that an annular flow channel (56) is formed between the clamping block (52) and the outer sleeve (2), and the annular flow channel (56) is also used for passing the coolant.

7. The stack-mounted fuel irradiation device according to claim 3, characterized in that: The resistance plug (6) comprises a plugging body (61) axially arranged in the outer sleeve (2), one end of the plugging body (61) is provided with a plurality of upper support columns (62) at intervals along the circumferential direction, and the other end of the plugging body (61) is provided with a plurality of lower support columns (63) at intervals along the circumferential direction, and both the upper support columns (62) and the lower support columns (63) partially protrude from the outer wall of the plugging body (61) in the radial direction and cooperate with the inner wall of the outer sleeve (2) so as to form a resistance flow channel between the plugging body (61) and the outer sleeve (2).

8. The reactor-mounted fuel irradiation device according to claim 7, characterized in that: A plurality of annular flow-blocking teeth (64) are arranged at positions relative to the resistance flow channel on the outer peripheral surface of the blocking body (61); the plurality of flow-blocking teeth (64) are arranged at equal intervals along the axial direction; the sum of the interval between two adjacent flow-blocking teeth (64) and the tooth width of a single flow-blocking tooth (64) is 10 mm; the tooth width of a single flow-blocking tooth (64) is 2 mm to 5 mm; and the tooth depth of a single flow-blocking tooth (64) is less than or equal to 3 mm.

9. The stack-mounted fuel irradiation device according to claim 3, characterized in that: The mixer (7) is a disc-shaped structure. The outer wall of the mixer (7) cooperates with the outer sleeve (2). The mixer (7) is evenly distributed with a plurality of guide holes (71) penetrating the mixer (7). The center lines of the plurality of guide holes (71) intersect, and the intersection point is located on the first direction side of the mixer (7).

10. The stack-mounted fuel irradiation device according to claim 9, characterized in that: The inclination angle of the center line of the guide hole (71) relative to the center axis of the flow mixer (7) is less than or equal to 10 degrees.

Images