Research reactor core outlet temperature measuring device and replacement method thereof

Abstract

The invention discloses a reactor core outlet temperature measuring device for a research reactor and a replacement method thereof, and belongs to the technical field of research reactor structure design. The device comprises a measuring plate and at least one group of supporting and guiding parts arranged on the measuring plate, the measuring plate is arranged at the lower part of the reactor internals, and a plurality of thermocouple thermometers are arranged on the plate surface of the measuring plate, so that the temperature of any position of a reactor core outlet can be conveniently measured; the supporting and guiding component comprises a thermocouple protection tube, a radial limiting mechanism and a thermocouple sealing assembly. According to the reactor core outlet temperature measuring device for the research reactor, the thermocouple thermometer can be integrally replaced, the structure is convenient to assemble and disassemble, and when the thermocouple thermometer breaks down and needs to be replaced, the reactor core outlet temperature measuring device and the thermocouple thermometer on the measuring plate can be integrally disassembled; the thermocouple and the thermometer can be replaced outside a research reactor, so that the temperature measurement requirement of a reactor core outlet can be continuously met.

Description

Technical Field

[0001] The present invention relates to the technical field of research reactor structure design, and in particular to a core outlet temperature measuring device for a research reactor and a replacement method thereof. Background Art

[0002] As a type of reactor, research reactors are important carriers and platforms for conducting experimental research on nuclear energy technology. For a long time, the research reactors designed and built in my country have provided valuable experimental data for scientific researchers.

[0003] After years of operation and use, the research reactor has also exposed some issues. To ensure safe and stable operation, thermocouples are installed at the core outlet, supplemented by corresponding in-core measurement mechanisms to ensure their reliability. However, this in-core measurement mechanism is a fixed structure and cannot be replaced after the research reactor is put into operation. During operation, some thermocouples fail and become inoperative. Even if the research reactor can continue to operate for an extended period of time, these in-core thermocouples and measurement mechanisms cannot be replaced. If all thermocouples fail, the core temperature measurement function will be completely lost. Summary of the Invention

[0004] The purpose of the present invention is to provide a core outlet temperature measuring device for a research reactor and a replacement method thereof, so as to solve the problem that the existing research reactor core measurement mechanical mechanism cannot be replaced. A core outlet temperature measuring device for a research reactor that can be replaced as a whole is provided. The device can provide support and protection for a thermocouple thermometer for measuring the core outlet temperature during the operation and shutdown of the research reactor for refueling, and at the same time has good guiding and sealing performance, providing favorable conditions for the installation and replacement of the thermocouple thermometer.

[0005] The technical solution of the present invention to solve the above technical problems is as follows: The present invention provides a core outlet temperature measuring device for a research reactor, comprising: a measuring plate and at least one set of supporting and guiding components arranged on the measuring plate; A measurement plate, which is disposed below the research reactor internals and has a plurality of thermocouple thermometers disposed on its surface for measuring the temperature at any position of the core outlet; The support and guide component comprises: A thermocouple protection tube, which is used to protect and guide a cluster consisting of a plurality of thermocouple thermometers; a radial limiting mechanism, one end of which is disposed on the thermocouple protection tube, and the other end of which is fixed to a flow distributor support frame in the pressure vessel; A thermocouple sealing assembly is provided at the end of the thermocouple protection tube away from the measurement plate.

[0006] Furthermore, in the core outlet temperature measurement device for a research reactor, each of the thermocouple thermometers is fixed to the surface of the measurement plate by a fixing clip.

[0007] Furthermore, in the core outlet temperature measuring device for a research reactor, the shape of the measuring plate is circular.

[0008] Furthermore, in the core outlet temperature measuring device for the research reactor, the supporting and guiding component also includes a fixed sleeve, an oblong hole is opened in the middle of the side wall of the fixed sleeve, and a cluster composed of several thermocouple thermometers extends upward into the fixed sleeve through the oblong hole on the fixed sleeve, and continues to extend into the thermocouple protection tube.

[0009] Furthermore, in the core outlet temperature measuring device for a research reactor, the supporting guide component further includes: a sleeve bracket, one end of which is fixedly connected to the outer edge of the measuring plate, and the other end of which is fixedly connected to the bottom of the fixed sleeve.

[0010] Furthermore, in the core outlet temperature measuring device for a research reactor, the radial limiting mechanism includes: a plug, a limiting plate, a lifting lug, a rotation pin and a backing plate; The plug is vertically inserted into the socket on the flow distributor support frame, and a pad for supporting the plug is provided between the plug and the distributor support frame; One end of the limit plate has an opening for the thermocouple protection tube to pass through, and the other end of the limit plate is connected to the plug through the rotating pin; a lifting lug is provided on the limit plate, and the limit plate can be rotated by matching the hanger with the lifting lug.

[0011] Furthermore, in the core outlet temperature measuring device for a research reactor, the thermocouple sealing assembly includes a sealing flange, a sealing joint, and a thermocouple guide tube; The sealing flange is connected to the core measurement sealing pipe seat flange on the pressure vessel top cover of the research reactor and is sealed by a sealing gasket; The sealing flange is provided with a vertical through hole, the thermocouple conduit is correspondingly installed in the through hole of the sealing flange, and the cluster consisting of a plurality of the thermocouple thermometers extends to the sealing flange through the thermocouple protection tube and is led out through the thermocouple conduit; The sealing joint and the sealing flange are respectively arranged at both ends of the thermocouple conduit.

[0012] Furthermore, in the core outlet temperature measurement device for the research reactor, there are 28 core outlet temperature measurement points in total, and each measurement point is arranged with one of the thermocouple thermometers.

[0013] Furthermore, in the core outlet temperature measuring device for a research reactor, two groups of support and guide components are provided, and each group of support and guide components accommodates 14 of the thermocouple thermometers.

[0014] The present invention also provides a method for installing a core outlet temperature measuring device for a research reactor, comprising: Step 1: Thermocouple thermometers are placed at the 28 measurement points on the measurement board according to the predetermined positions and fixed with fixing clips. The placement and orientation of the thermocouple thermometers can be flexibly adjusted according to the structural design of the research reactor. A temporary label corresponding to the measurement point position should be affixed to one end of each thermocouple thermometer. Step 2: After the thermocouples are arranged, they are divided into two bundles and passed through the oblong holes on the fixed sleeve in sequence. The thermocouple bundling tooling is used to bundle each thermocouple; Step 3: Install the measurement plate on the secondary support assembly of the research reactor outside the reactor. Once installed, hoist the secondary support assembly into the pressure vessel of the research reactor. Step 4: Use the thermocouple protection tube straightening tool to hoist the two thermocouple protection tubes into the stack one by one, ensuring that the thermocouple protection tubes are completely fixed on the fixing sleeve; Step 5: Hoist the internal components to the top of the secondary support assembly to achieve axial positioning of the measurement plate; Step 6: While keeping the limit plate in the vertical position, hoist the radial limit assembly onto the in-pile flow distributor support frame. After installation, keep the limit plate in the radial limit assembly in the vertical position. Rotating the limit plate will interfere with the thermocouple protection tube. Step 7: Lift the two thermocouple protection tubes to a certain height so that the lower end surfaces of the thermocouple protection tubes are higher than the upper surface of the radial limiter, ensuring that the limiter plate does not interfere with the thermocouple protection tubes during rotation; Step 8: Use the lifting device to rotate the limit plate of the radial limit device to a horizontal state, and then insert the thermocouple protection tube into place; Step 9: After installing the research reactor's pressure vessel cover, install the thermocouple seal assembly in sequence to connect the thermocouple thermometer to the measurement system. During installation, ensure that the thermocouple thermometer is matched with the correspondingly marked sealing joint.

[0015] The present invention also provides a method for replacing a core outlet temperature measuring device for a research reactor, comprising: Step 10: After the research reactor is shut down, remove the thermocouple seal assembly; Step 11: Use the thermocouple clustering tool to cluster and temporarily fix the scattered thermocouple thermometers to prevent them from falling into the research reactor due to lack of restraint; Step 12: Lift the two thermocouple protection tubes out of the pile. Keep them vertical during the lifting process. After they are completely out of the thermocouple cluster tooling, lift them into the water tank for storage. Then, use the lifting device to lift the radial limit assembly to maintain a vertical position. Step 13: After removing the research reactor's pressure vessel head, the reactor internals and secondary support assembly are removed and hoisted to a storage rack in the storage pool using a hoist. The core outlet temperature measurement device is also hoisted out of the reactor. Step 14: Use the remote disassembly tool to physically separate the secondary support assembly from the basket assembly of the reactor internals. Use a long-pole tool to shear the thermocouple thermometer cluster on the measurement plate, thereby separating the measurement plate from the reactor internals. The reactor internals are then lifted away. Step 15: Lift the measuring plate off the secondary support assembly; then, lift the new measuring plate, which has been remanufactured and installed with the thermocouple thermometer, as well as the sleeve bracket and fixed sleeve, onto the secondary support assembly; Step 16: Reinstall the replaced core outlet temperature measurement device in the research reactor using the same installation steps as the initial installation of the core outlet temperature measurement device.

[0016] The present invention has the following beneficial effects: The core outlet temperature measurement device for a research reactor provided by the present invention comprises a cluster of thermocouple thermometers mounted on a measurement plate. These thermocouples are passed through a thermocouple protection tube and a thermocouple seal assembly, leading out of the reactor to connect to a measurement system. A radial limit mechanism constrains the thermocouple protection tube to prevent shaking. This device enables the replacement of the thermocouple thermometers as a whole, boasting a convenient assembly and disassembly structure. If a thermocouple thermometer fails and needs replacement, the core outlet temperature measurement device and the thermocouple thermometer on the measurement plate can be disassembled as a whole, allowing the thermocouple thermometer to be replaced outside the reactor, thus consistently meeting the core outlet temperature measurement needs of research reactors.

[0017] The core outlet temperature measurement device for a research reactor provided by the present invention can realize the function of replacing the thermocouple thermometer as a whole by replacing the measuring plate as a whole. The core outlet temperature measurement device for a research reactor provided by the present invention adopts an integrated structure. It can not only bundle the thermocouple thermometers used to measure the core outlet temperature and then lead them out of the reactor through the top cover of the research reactor pressure vessel to realize the measurement of the core outlet temperature; at the same time, the core outlet temperature measurement device and the internal components of the reactor can be lifted out of the reactor together through the integrated replacement method, and the thermocouple thermometer can be replaced as a whole outside the reactor, avoiding the loss of the core outlet temperature measurement function due to the failure of the thermocouple thermometer to be replaced. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The drawings described herein are used to provide a further understanding of the embodiments of the present invention, constitute a part of this application, and do not constitute a limitation of the embodiments of the present invention. In the drawings: Figure 1 A schematic structural diagram of a core outlet temperature measuring device for a research reactor provided by the present invention; Figure 2 A schematic top view of a core outlet temperature measuring device for a research reactor provided by the present invention; Figure 3 This is a schematic structural diagram of a thermocouple sealing assembly in a core outlet temperature measurement device for a research reactor provided by the present invention; Figure 4 The present invention provides Figure 2 An enlarged structural diagram of the middle radial limit mechanism; Figure 5 The present invention provides Figure 1 A partial enlarged view of .

[0019] Markings and corresponding parts names in the accompanying drawings: In the figure: 10 - measuring plate, 20 - thermocouple thermometer, 21 - fixing clamp, 31 - thermocouple protection tube, 32 - radial limit mechanism, 321 - limit plate, 322 - lifting ear, 323 - rotation pin, 33 - thermocouple sealing assembly, 331 - sealing flange, 332 - sealing joint, 333 - thermocouple guide tube, 334 - sealing gasket, 34 - fixing sleeve, 35 - sleeve bracket, 40 - flow distributor support frame, 50 - internal component. DETAILED DESCRIPTION

[0020] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings herein can be arranged and designed in various different configurations.

[0021] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention as claimed, but rather merely represents selected embodiments of the present invention. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without creative effort shall fall within the scope of protection of the present invention.

[0022] Example 1 Please refer to Figure 1-5 The core outlet temperature measuring device for a research reactor provided by an embodiment of the present invention includes: a measuring plate 10 and at least one set of supporting and guiding components provided on the measuring plate 10; A measuring plate 10 is provided on an internal component 50 of the research reactor, and a plurality of thermocouple thermometers 20 are provided on a surface of the measuring plate 10; The supporting and guiding components include: Thermocouple protection tube 31, which is used to protect and guide the cluster consisting of several thermocouple thermometers 20; A radial limiting mechanism 32, one end of which is disposed on the thermocouple protection tube 31, and the other end of which is fixed to the flow distributor support frame 40 in the pressure vessel; The thermocouple sealing assembly 33 is provided at the end of the thermocouple protection tube 31 away from the measurement board 10 .

[0023] In this embodiment, the thermocouple protection tube 31 is an elongated circular tube structure, and the thermocouple thermometers 20 are bundled and extend upward through the thermocouple protection tube 31. The thermocouple protection tube 31 is used to protect and guide the bundle of thermocouple thermometers 20. Two small holes are symmetrically opened on the top side wall of the thermocouple protection tube 31 to facilitate lifting.

[0024] In this embodiment, the radial limiting assembly is mainly used to limit the shaking of the thermocouple protection tube 31 caused by flow-induced vibration in the research reactor. The radial limiting device is arranged in the middle position of the thermocouple protection tube 31 and fixed on the flow distributor support frame 40 in the pressure vessel, thereby limiting the thermocouple protection tube 31.

[0025] The core outlet temperature measurement device for a research reactor provided by the present invention comprises a cluster of thermocouple thermometers 20 mounted on a measurement plate 10. These thermocouples are guided through a thermocouple protection tube 31 and a thermocouple seal assembly, leading out of the reactor to connect to the measurement system. A radial limiter 32 constrains the thermocouple protection tube 31 to prevent movement. This device allows for the complete replacement of the thermocouple thermometers 20, boasting a convenient assembly and disassembly structure. If a thermocouple thermometer 20 fails and requires replacement, the core outlet temperature measurement device and the thermocouple thermometer 20 on the measurement plate 10 can be disassembled as a whole, allowing the thermocouple thermometer 20 to be replaced outside the reactor, thus consistently meeting the needs for core outlet temperature measurement.

[0026] In actual use, the thermocouple thermometer 20 can be replaced as a whole by replacing the measuring plate 10. The core outlet temperature measurement device for a research reactor provided by the present invention adopts an integrated structure. It can not only bundle the thermocouple thermometers 20 used for measuring the core outlet temperature and then guide them out of the reactor through the pressure vessel top cover of the research reactor to achieve the measurement of the core outlet temperature, but also can be hoisted out of the reactor together with the internal components 50 through the integrated replacement method, so that the thermocouple thermometer 20 can be replaced as a whole outside the reactor, avoiding the loss of the core outlet temperature measurement function due to the failure of the thermocouple thermometer 20 to be replaced.

[0027] In some feasible embodiments, each thermocouple thermometer 20 is fixed to the surface of the measuring plate 10 by a fixing clamp 21. The thermocouple thermometer 20 is fixed to the surface of the measuring plate 10 by the fixing clamp 21, and the thermocouple thermometers 20 on the measuring plate 10 are grouped into two bundles by the fixing clamp 21. The fixing clamp 21 can be selected in different specifications according to the number of thermocouple thermometers 20 fixed. In this embodiment, 28 thermocouple thermometers 20 are fixed to the measuring plate 10 by the fixing clamp 21. The arrangement is shown in FIG. Figure 2 .

[0028] In some feasible embodiments, the shape of the measurement plate 10 is circular, which is more suitable for use in in-pile conditions.

[0029] In some feasible embodiments, the support and guide component further includes a fixed sleeve 34, with an oblong hole formed in the middle of the side wall of the fixed sleeve 34. The cluster of thermocouple thermometers 20 extends upward through the oblong hole on the fixed sleeve 34 into the fixed sleeve 34 and further into the thermocouple protection tube 31. In this embodiment, the fixed sleeve 34 is a hollow circular tube structure with an oblong hole formed in the middle of the side wall. The cluster of thermocouple thermometers 20 extends upward through the oblong hole into the fixed sleeve 34 and the thermocouple protection tube 31. The top of the fixed sleeve 34 is conical, which can provide guidance for the thermocouple protection tube 31 during installation, facilitating smooth insertion of the thermocouple protection tube 31 into the fixed sleeve 34. A stepped shaft is provided below the guide head of the fixed sleeve 34 and above the oblong hole to support and limit the thermocouple protection tube 31.

[0030] In some feasible embodiments, the support and guide component further includes a sleeve bracket 35, one end of which is fixedly connected to the outer edge of the measuring plate 10, and the other end of which is fixedly connected to the bottom of the fixed sleeve 34. In this embodiment, the sleeve bracket 35 is wrench-shaped, with one side of the sleeve bracket 35 having a circular arc cross-section with a central angle of 10°. It has four through-holes evenly distributed therein, and is secured to the edge of the measuring plate 10 via a threaded connection. The other side of the sleeve bracket 35 is also threaded to secure the fixed sleeve 34.

[0031] In some feasible embodiments, the radial limiting mechanism 32 includes: a plug, a limiting plate 321, a lifting ear 322, a rotating pin 323 and a pad; The plug is vertically inserted into the jack on the flow distributor support frame 40, and a pad for supporting the plug is provided between the plug and the distributor support frame 40; One end of the limiting plate 321 has an opening for the thermocouple protection tube 31 to pass through, and the other end of the limiting plate 321 is connected to the plug through a rotating pin 323; a lifting ear 322 is provided on the limiting plate 321, and the limiting plate 321 can be rotated by matching the hanging device with the lifting ear 322 to facilitate the installation and replacement of the thermocouple protection tube 31.

[0032] In this embodiment, the plug is vertically inserted into the socket on the flow distributor support frame 40 and supported on the flow distributor support frame 40 by the pad above the plug, thereby achieving axial support for the plug; a support plate extends from the side wall of the plug, and after the support plate is inserted into the flow distributor support frame 40 along with the plug, it can achieve circumferential limit of the plug; a rotation pin 323 is provided above the pad, and one side of the limit plate 321 is pin-connected to the plug, so that the limit plate 321 can be rotated after the connection. The limit plate 321 is provided with a lifting lug 322, which can be rotated using a corresponding lifting device. The other side of the limit plate 321 is an open structure, which can protect and limit the thermocouple protection tube 31 passing through it.

[0033] The limit plate 321 has two states during the installation and maintenance of the research reactor: one is that during normal operation, the limit plate 321 is kept in a horizontal state by the pad on the plug to prevent the limit plate 321 from rotating downward. At this time, the limit plate 321 can realize the limiting function of the thermocouple protection tube 31; the other is that during the installation and maintenance process, the limit plate 321 needs to be pulled up to a vertical state using a sling, which can facilitate the installation and replacement work.

[0034] In some feasible embodiments, the thermocouple sealing assembly 33 includes a sealing flange 331 , a sealing joint 332 , and a thermocouple conduit 333 ; The sealing flange 331 is connected to the core measurement sealing pipe seat flange on the pressure vessel top cover of the research reactor and is sealed by the sealing gasket 334; The sealing flange 331 is provided with a vertical through hole, and the thermocouple conduit 333 is correspondingly installed in the through hole of the sealing flange 331. The cluster consisting of several thermocouple thermometers 20 extends to the sealing flange 331 through the thermocouple protection tube 31 and is led out through the thermocouple conduit 333; The two ends of the thermocouple tube 333 are respectively a sealing joint 332 and a sealing flange 331 .

[0035] In this embodiment, the thermocouple seal assembly 33 is one of the key structures for guiding the thermocouple thermometers 20 out of the research reactor. It provides a channel and seal for the thermocouple thermometers 20. The thermocouple seal assembly 33 mainly consists of a sealing flange 331, a sealing joint 332, and a thermocouple guide tube 333. The sealing flange 331 is connected to the core measurement sealing tube seat flange on the research reactor's pressure vessel top cover via threads, and the flanges are sealed by a sealing gasket 334. The sealing flange 331 is provided with vertical through-holes, and the thermocouple guide tubes 333 are each an elongated circular tube structure. The thermocouple guide tubes 333 are installed in the through-holes of the sealing flange 331. After the thermocouple thermometers 20 are bundled, pass through the thermocouple protection tube 31, and extend to the sealing flange 331, they are introduced into the thermocouple guide tube 333 through the through-holes in the sealing flange 331 and then guided out of the reactor.

[0036] The thermocouple thermometer 20 is connected to the nuclear measurement system by the sealing joint 332, thereby measuring the core outlet temperature. Preferably, the sealing joint 332 adopts the mature Swagelok sealing joint 332.

[0037] In order to facilitate the arrangement of the sealing joints 332 and avoid the interference of the sealing joints 332 in the axial direction, the sealing joints 332 are arranged in layers using thermocouple tubes 333 of different heights. From top to bottom, there are 4 layers, 4, 4, and 2 groups of sealing joints 332. Figure 3 shown.

[0038] In some feasible embodiments, there are 28 stack outlet temperature measurement points, each of which is equipped with a thermocouple thermometer 20. Each temperature measurement point uses a thermocouple thermometer 20 to measure temperature, and there are a total of 28 thermocouple thermometers 20 in the entire stack.

[0039] In some feasible implementations, two sets of support and guide components are provided, each accommodating 14 thermocouple thermometers 20. Two sets of support and guide components are arranged within the reactor, each capable of accommodating 14 thermocouple thermometers 20, achieving full coverage of the reactor's 28 core outlet temperature measurement points. In this embodiment, each set of 14 thermocouple thermometers 20 is bundled together and extends upward through the oblong hole in the sleeve bracket 35. Protected by the thermocouple protection tube 31, each thermocouple ultimately extends outside the reactor through a corresponding thermocouple guide tube 333 in the thermocouple sealing assembly 33. The thermocouple thermometer 20 is sealed using a Swagelok sealing joint 332.

[0040] Example 2 The method for replacing a core outlet temperature measuring device for a research reactor provided in this embodiment is based on the core outlet temperature measuring device for a research reactor in Example 1, and includes: The core outlet temperature measuring device for the research reactor is hoisted together with the in-core component 50 to an external water pool for storage, and the core outlet temperature measuring device for the research reactor is separated from the in-core component 50 by a remote operation tool; After replacing the measuring plate 10 and its thermocouple thermometer 20, the replaced core outlet temperature measuring device for the research reactor is hoisted together with the in-core component 50 to be installed inside the reactor, thereby realizing the overall disassembly of the core outlet temperature measuring device and the replacement of the thermocouple thermometer 20 outside the reactor.

[0041] Specifically, the replacement method of the core outlet temperature measurement device for a research reactor provided in this embodiment includes an installation process and a disassembly process. The prerequisite for installing the core outlet temperature measurement device for a research reactor is that the pressure vessel has been installed in place and the pressure vessel top cover of the research reactor has not yet been installed.

[0042] The specific steps of the installation process are as follows: Step 11: Thermocouple thermometers 20 are arranged at 28 measuring points on the measuring plate 10 according to the predetermined positions and fixed with fixing clamps 21. The arrangement positions and directions are shown in FIG. Figure 2 For easy identification, a temporary mark corresponding to the measuring point position should be affixed to one end of each thermocouple thermometer 20.

[0043] Step 12: After the thermocouples are arranged, they are divided into two bundles and sequentially passed through the oblong holes on the fixed sleeve 34 . The guide head in the thermocouple bundling tooling bundles each thermocouple.

[0044] Step 13: Install the measurement plate 10 on the secondary support assembly outside the reactor. After installation, hoist the secondary support assembly into the pressure vessel.

[0045] Step 14: Use the thermocouple protection tube 31 straightening tool to hoist the two thermocouple protection tubes 31 into the stack in sequence, ensuring that the thermocouple protection tubes 31 are completely fixed on the fixing sleeve 34 .

[0046] Step 15: Hoist the internals 50 above the secondary support assembly to achieve axial positioning of the measurement plate 10. During the hoisting process, be sure to protect the two thermocouple protection tubes 31 to avoid scratches.

[0047] Step 16: Keep the limit plate 321 in the vertical position and hoist the radial limit assembly onto the in-stack flow distributor support frame 40. After installation, keep the limit plate 321 in the radial limit assembly in the vertical position. Rotating the limit plate 321 will interfere with the thermocouple protection tube 31.

[0048] Step 17: Lift the two thermocouple protection tubes 31 to a certain height respectively. Preferably, make their lower end surfaces higher than the upper surface of the radial limiting device to ensure that the limiting plate 321 does not interfere with the thermocouple protection tube 31 during rotation.

[0049] Step 18: Use a hoist to rotate the radial limiter plate 321 to a horizontal position. Insert the thermocouple protection tube 31 into place. During the insertion process, be sure to keep the thermocouple protection tube 31 vertical to prevent it from scraping against the center hole of the limiter plate 321.

[0050] Step 19: After installing the research reactor's pressure vessel head, install the thermocouple seal assembly 33 in sequence, thereby connecting the thermocouple thermometer 20 to the measurement system. During installation, ensure that the markings on the thermocouple thermometer 20 match the correspondingly marked seal joint 332.

[0051] During the operation of a research reactor, if the thermocouple thermometer 20 fails, and the core outlet temperature measurement function is lost, the entire core outlet temperature measurement device and the measurement plate 10 can be disassembled and replaced with a new measurement plate 10. The replacement of the thermocouple thermometer 20 and the measurement plate 10 is carried out outside the reactor. The core outlet temperature measurement device for a research reactor can realize the function of replacing the thermocouple thermometer 20 as a whole. The specific steps of the disassembly process are as follows: Step 21: After the research reactor is shut down, remove the thermocouple seal assembly 33; Step 22: Use the guide head in the thermocouple clustering tool to cluster and temporarily fix the scattered thermocouple thermometers 20 to prevent the thermocouple thermometers 20 from falling into the research reactor due to lack of restraint.

[0052] Step 23: Lift the two thermocouple protection tubes 31 out of the pile. Keep the thermocouple protection tubes 31 vertical during the lifting process. Once the thermocouple protection tubes 31 are completely out of the thermocouple cluster tooling, lift them into the water tank for storage. Then, use a lifting device to lift the radial limit assembly to maintain a vertical position.

[0053] Step 24: After removing the research reactor's pressure vessel head, the reactor internals 50 and secondary support assembly are removed and hoisted to a storage rack in the storage pool using a hoist. The core outlet temperature measurement device is also hoisted out of the reactor.

[0054] Step 25: Use a remote disassembly tool to physically separate the secondary support assembly from the hanging basket assembly of the reactor internals 50. Use a long-pole tool to shear the cluster of thermocouple thermometers 20 on the measurement plate 10, thereby separating the measurement plate 10 from the reactor internals 50. The reactor internals 50 are then hoisted away. The thermocouple thermocouples 20 are bundled and properly stored, and the thermocouple bundling tooling is retained for future use.

[0055] Step 26: Lift the measuring plate 10 from the secondary support assembly. Subsequently, lift the new measuring plate 10 with the thermocouple thermometer 20 remanufactured and installed thereon, along with the sleeve bracket 35 and the fixing sleeve 34, onto the secondary support assembly.

[0056] Step 27: Using the same installation steps as the initial installation of the core outlet temperature measurement device, reinstall the replaced measurement plate 10 and the core outlet temperature measurement device in the research reactor. This completes the replacement of the thermocouple thermometer 20 used to measure the core outlet temperature.

[0057] The above specific implementation methods further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above are only specific implementation methods of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A core outlet temperature measuring device for a research reactor, characterized in that: include: A measuring plate and at least one set of supporting and guiding components arranged on the measuring plate; A measuring plate, which is arranged at the lower part of the reactor internals and has a plurality of thermocouple thermometers on its surface for measuring the temperature at any position of the core outlet; The support and guide component comprises: A thermocouple protection tube, which is used to protect and guide a cluster consisting of a plurality of thermocouple thermometers; a radial limiting mechanism, one end of which is disposed on the thermocouple protection tube, and the other end of which is fixed to a flow distributor support frame in the pressure vessel; A thermocouple sealing assembly is provided at the end of the thermocouple protection tube away from the measurement plate.

2. The core outlet temperature measuring device for a research reactor according to claim 1, characterized in that: Each of the thermocouple thermometers is fixed on the plate surface of the measuring plate through a fixing clip.

3. The core outlet temperature measuring device for a research reactor according to claim 1, characterized in that: The measuring plate is circular in shape.

4. The core outlet temperature measuring device for a research reactor according to claim 1, characterized in that: The supporting guide component also includes a fixed sleeve, and an oblong hole is opened in the middle of the side wall of the fixed sleeve. The cluster composed of several thermocouple thermometers passes through the oblong hole on the fixed sleeve and extends upward into the fixed sleeve, and continues to extend into the thermocouple protection tube.

5. The core outlet temperature measuring device for a research reactor according to claim 4, characterized in that: The supporting and guiding component further includes: a sleeve bracket, one end of which is fixedly connected to the outer edge of the measuring plate, and the other end of which is fixedly connected to the bottom of the fixed sleeve.

6. The core outlet temperature measuring device for a research reactor according to claim 1, characterized in that: The radial limiting mechanism includes: a plug, a limiting plate, a lifting lug, a rotating pin and a pad; The plug is vertically inserted into the socket on the flow distributor support frame, and a pad for supporting the plug is provided between the plug and the distributor support frame; One end of the limit plate has an opening for the thermocouple protection tube to pass through, and the other end of the limit plate is connected to the plug through the rotating pin; a lifting lug is provided on the limit plate, and the limit plate can be rotated by matching the hanger with the lifting lug.

7. The core outlet temperature measuring device for a research reactor according to claim 1, characterized in that: The thermocouple sealing assembly includes a sealing flange, a sealing joint and a thermocouple conduit; The sealing flange is connected to the core measurement sealing pipe seat flange on the top cover of the pressure vessel of the research reactor and is sealed by a sealing gasket; The sealing flange is provided with a vertical through hole, the thermocouple conduit is correspondingly installed in the through hole of the sealing flange, and the cluster consisting of a plurality of the thermocouple thermometers extends to the sealing flange through the thermocouple protection tube and is led out through the thermocouple conduit; The sealing joint and the sealing flange are respectively arranged at both ends of the thermocouple conduit.

8. The core outlet temperature measuring device for a research reactor according to claim 1, characterized in that: There are 28 stack outlet temperature measuring points in total, and each measuring point is equipped with a thermocouple thermometer; The supporting and guiding components are provided in two groups, and each group of the supporting and guiding components accommodates 14 of the thermocouple thermometers.

9. A method for installing a core outlet temperature measuring device for a research reactor according to any one of claims 1 to 8, characterized in that: include: Step 1: Thermocouple thermometers are placed at the 28 measurement points on the measurement board according to the predetermined positions and fixed with fixing clips. The placement and orientation of the thermocouple thermometers can be flexibly adjusted according to the structural design of the research reactor. A temporary label corresponding to the measurement point position should be affixed to one end of each thermocouple thermometer. Step 2: After the thermocouples are arranged, they are divided into two bundles and passed through the oblong holes on the fixed sleeve in sequence. The thermocouple bundling tooling is used to bundle each thermocouple; Step 3: Install the measurement plate on the secondary support assembly of the research reactor outside the reactor. Once installed, hoist the secondary support assembly into the pressure vessel of the research reactor. Step 4: Use the thermocouple protection tube straightening tool to hoist the two thermocouple protection tubes into the stack one by one, ensuring that the thermocouple protection tubes are completely fixed on the fixing sleeve; Step 5: Hoist the internal components to the top of the secondary support assembly to achieve axial positioning of the measurement plate; Step 6: While keeping the limit plate in the vertical position, hoist the radial limit assembly onto the in-pile flow distributor support frame. After installation, keep the limit plate in the radial limit assembly in the vertical position. Rotating the limit plate will interfere with the thermocouple protection tube. Step 7: Lift the two thermocouple protection tubes to a certain height so that the lower end surfaces of the thermocouple protection tubes are higher than the upper surface of the radial limiter, ensuring that the limiter plate does not interfere with the thermocouple protection tubes during rotation; Step 8: Use the lifting device to rotate the limit plate of the radial limit device to a horizontal state, and then insert the thermocouple protection tube into place; Step 9: After installing the research reactor's pressure vessel cover, install the thermocouple seal assembly in sequence to connect the thermocouple thermometer to the measurement system. During installation, ensure that the thermocouple thermometer is matched with the correspondingly marked sealing joint.

10. A method for replacing a core outlet temperature measuring device for a research reactor according to any one of claims 1 to 8, characterized in that: include: Step 10: After the research reactor is shut down, remove the thermocouple seal assembly; Step 11: Use the thermocouple clustering tool to cluster and temporarily fix the scattered thermocouple thermometers to prevent them from falling into the research reactor due to lack of restraint; Step 12: Lift the two thermocouple protection tubes out of the pile. Keep them vertical during the lifting process. After they are completely out of the thermocouple cluster tooling, lift them into the water tank for storage. Then, use the lifting device to lift the radial limit assembly to maintain a vertical position. Step 13: After removing the research reactor's pressure vessel head, the reactor internals and secondary support assembly are removed and hoisted to a storage rack in the storage pool using a hoist. The core outlet temperature measurement device is also hoisted out of the reactor. Step 14: Use the remote disassembly tool to physically separate the secondary support assembly from the basket assembly of the reactor internals. Use a long-pole tool to shear the thermocouple thermometer cluster on the measurement plate, thereby separating the measurement plate from the reactor internals. The reactor internals are then lifted away. Step 15: Lift the measuring plate off the secondary support assembly; then, lift the new measuring plate, which has been remanufactured and installed with the thermocouple thermometer, as well as the sleeve bracket and fixed sleeve, onto the secondary support assembly; Step 16: Reinstall the replaced core outlet temperature measurement device in the research reactor using the same installation steps as the initial installation of the core outlet temperature measurement device.

Images