Assembly method of heat pipe type reactor and heat pipe type reactor

Abstract

The invention discloses an assembly method of a heat pipe type reactor and the heat pipe type reactor, and belongs to the field of nuclear power. The assembly method of the heat pipe type reactor comprises the following steps: closing one end of each mounting hole of the grid base body, vertically arranging the grid base body to enable the closed end to be located at the bottom, injecting filling slurry containing heat-conducting powder and a dispersing agent into the mounting holes, then inserting pipe fittings into the mounting holes until the filling slurry overflows, and finally assembling the grid base body into the mounting holes. The gap between the pipe fitting and the mounting hole is uniformly filled with the filling slurry in a forced flowing mode; and heating to cure and shape the filling slurry. The method can effectively eliminate the assembly gap between the grid substrate and the pipe fitting of the heat pipe type reactor, and improves the heat transfer efficiency and the safety margin of the reactor.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of nuclear power, and particularly relates to an assembly method of a heat pipe type reactor and the heat pipe type reactor. BACKGROUND

[0002] The heat pipe type reactor adopts a full solid structure, and does not set a liquid primary loop, but utilizes a solid core to directly output heat generated by fuel rods through contact heat transfer, and delivers the heat to a power output end through a heat pipe. Compared with a pressurized water reactor, the heat pipe type reactor is compact in structure, good in inherent safety, and convenient to flexibly deploy, and is thus considered to have a good application prospect. However, the solid heat transfer feature of the heat pipe type reactor also puts high requirements on the assembly precision of components, and once an assembly gap appears at a heat transfer interface, heat resistance will increase, heat transfer will be poor, the power generation efficiency of the reactor will be affected, and even an operation risk will be caused. Therefore, providing a method capable of effectively eliminating an assembly gap has a positive significance for improving the safety margin of the heat pipe type reactor. SUMMARY

[0003] The present application aims to provide an assembly method of a heat pipe type reactor, and eliminate an assembly gap of a solid core. The present application also provides a heat pipe type reactor.

[0004] According to an embodiment of one aspect of the present application, an assembly method of a heat pipe type reactor is provided, the heat pipe type reactor comprising a grid base body and a pipe fitting, the grid base body comprising a mounting hole for mounting the pipe fitting, and the pipe fitting comprising a heat pipe and a fuel rod. Specifically, the method comprises the following steps:

[0005] Step a): closing one end of the mounting hole of the grid base body by arranging an end plug, and vertically arranging the grid base body so that the end provided with the end plug is located at the bottom;

[0006] Step b): injecting a filling slurry into the mounting hole, the filling slurry comprising a heat-conducting powder and a dispersing agent;

[0007] Step c): inserting the pipe fitting along the mounting hole, so that the filling slurry fills the gap between the mounting hole and the pipe fitting and overflows from the top end of the mounting hole;

[0008] Step d): removing the overflowing filling slurry, heating and heat-insulating the grid base body, and solidifying the filling slurry.

[0009] The above method can effectively eliminate the assembly gap in the solid core, improve the heat transfer efficiency, and at the same time, the assembly process can be carried out under normal pressure conditions, without changing the core structure, and is simple and convenient to operate and low in cost.

[0010] Further, in some embodiments, the gap size between the mounting hole and the pipe is 50-500 μm.

[0011] Further, in some embodiments, the viscosity of the filling slurry in step b) is 800-1200 Pa·s, and the yield strength is 180-230 Pa.

[0012] Further, in some embodiments, the heat-conducting powder in step b) comprises one or a combination of copper powder, iron powder, chromium powder, molybdenum powder, and nickel powder; the dispersant comprises one or a combination of ethanol, ethylene glycol, phosphate, and silicate; and the solid content in the filling slurry is 70-90%.

[0013] Further, in some embodiments, the heating temperature in step d) is not higher than 850°C.

[0014] Further, in some embodiments, the heating mode in step d) is to heat the heat pipe by using an external heat source.

[0015] Further, in some embodiments, the heating mode in step d) is to directly heat the grid substrate by using an electric heating rod.

[0016] Further, in some embodiments, the heating mode in step d) is to start the heat pipe reactor, and heat the grid substrate by using the fuel rod.

[0017] Further, in some embodiments, step d) further comprises a step of detecting the gap filling degree by using CT after sintering.

[0018] According to another aspect of the embodiments of the present application, a heat pipe reactor is provided, which comprises a grid substrate, a heat pipe, and a fuel rod, and is assembled by using the assembling method of the heat pipe reactor provided in any of the above embodiments. BRIEF DESCRIPTION OF DRAWINGS

[0019] Fig. 1 a schematic diagram of step a) in an embodiment;

[0020] Fig. 2 a schematic diagram of step b) in an embodiment;

[0021] Fig. 3 a schematic diagram of step c) in an embodiment;

[0022] Fig. 4 a schematic diagram of step d) in an embodiment.

[0023] Meaning of reference signs:

[0024] 1 - lattice base; 2 - pipe; 3 - mounting hole; 4 - filled slurry; 5 - end plug; 6 - cured filled slurry.

[0025] The above drawings are intended to provide a detailed description of the present application, so that those skilled in the art can understand the technical concept of the present application, and are not intended to limit the present application. In order to express concisely, the above drawings only schematically draw the structures related to the technical features of the present application, and do not strictly draw the complete structures and all details according to the actual proportions. DETAILED DESCRIPTION

[0026] The present application will be further described in detail through specific embodiments combined with the drawings.

[0027] Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the application. The appearances of the phrase that the phrase in various places in the specification are not necessarily referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of one another. Those skilled in the art will appreciate from the present description that embodiments of the application can comprise suitable combinations of other embodiments.

[0028] In the description herein, unless otherwise explicitly specified and limited, the technical terms "mounting", "connection", "connecting", and the like should be understood broadly, for example, can be movable connection, or fixed connection or integral. For those skilled in the art, the specific meanings of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0029] In the description herein, the terms indicating the orientation or position relationship such as "upper", "lower", "left", "right", "transverse", "longitudinal", "height", "length", "width", and the like are intended to accurately describe the embodiments and simplify the description, and are not intended to limit the parts or structures involved to have a specific orientation, to be installed or operated in a specific orientation, and cannot be understood as limiting the embodiments herein.

[0030] In the description herein, the terms "first", "second", and the like are only used to distinguish different objects, and cannot be understood as indicating relative importance or limiting the number, specific order or primary and secondary relationship of the technical features described. In the description herein, the meaning of "a plurality of" is at least two.

[0031] The heat pipe type reactor uses a solid core, and a fuel rod is inserted into a heat pipe in a grid base with a circular mounting hole. The heat generated by the fuel rod is conducted to the power output end by the heat pipe through solid heat conduction. Due to the dependence on contact heat conduction, if there is a gap between the grid base and the heat pipe or the fuel rod, the heat resistance will abnormally increase, which will significantly reduce the heat transfer efficiency, affect the output power of the reactor, and even cause a local overheating accident. The patent CN113643830A provides a technical solution of filling metal powder in the gap, but the metal powder has poor flowability and insufficient compactness, and the heat conduction efficiency is difficult to meet the requirements. The patent CN115862903A discloses a scheme of filling porous materials, which also has the problem of insufficient heat conduction efficiency. The scheme disclosed in the patent CN112117016B uses liquid heat conduction materials such as heat conduction glue, but these materials have poor heat conduction performance and have high-temperature decomposition problems. The patent CN120164642A discloses a technical solution of filling shape memory alloys, but the thermal cycle life of the shape memory alloy is limited, and the thermal expansion behavior is obvious, which cannot meet the service requirements of the heat pipe type reactor that needs to be frequently started and stopped.

[0032] In order to overcome the deficiencies of the prior art, an embodiment of one aspect of the present application provides an assembly method of a heat pipe type reactor, which can effectively eliminate the assembly gap between the grid base and the heat pipe and the fuel rod during assembly, optimize the heat transfer efficiency, and improve the safety of the heat pipe type reactor.

[0033] The heat pipe type reactor related to the embodiments of the present application includes a grid base and a pipe, the grid base is provided with a mounting hole for mounting the pipe, and the pipe includes a heat pipe and a fuel rod. Specifically, the method as shown in Figs. 1 to 4 includes the following steps:

[0034] Step a): end plugs 5 are arranged at one end of the mounting holes 3 of the grid base 1 to close them, the end plugs 5 can be made of wood, engineering plastic or ceramic material, or can be made of metal, and the end plugs 5 can be clamped in the mounting holes 3 or fixed by welding. After the end plugs 5 are arranged at the same end of all the mounting holes 3, the grid base is arranged vertically, and the end of the end plug 5 is located at the bottom, and the opening end of the mounting hole 3 is located at the top.

[0035] Step b): filling slurry 4 is injected into the mounting hole 3. In the preferred embodiment, the gap size between the mounting hole 3 and the pipe 2 is 50-500 microns, and the filling amount of the filling slurry 4 in a single mounting hole can be about 5 grams.

[0036] In the preferred embodiment, the viscosity of the filling slurry 4 is 800 Pa s-1 200 Pa s, and the yield strength is 180 Pa-230 Pa. The filling slurry comprises heat-conducting powder and dispersant, wherein the heat-conducting powder comprises one or a combination of copper powder, iron powder, chromium powder, molybdenum powder, and nickel powder; and the dispersant comprises one or a combination of ethanol, phosphate, and silicate.

[0037] Step c): inserting the pipe 2 into the mounting hole 3, in the preferred embodiment, the insertion end of the pipe 2 is provided with a hemispherical or conical end to guide the filling slurry 4, the filling slurry 4 is forced to fill into the gap between the pipe 2 and the mounting hole 3 by extrusion, the air in the gap is removed, the pipe 2 is fully inserted into the mounting hole 3, and the filling slurry 4 is fully filled into the gap and partially overflowed from the top end of the mounting hole 3.

[0038] Step d): removing the overflowed filling slurry 4, and heating and keeping the grid matrix 1 as a whole to make the filling slurry 4 completely change into the solidified filling slurry 6.

[0039] In the preferred embodiment, the heating temperature does not exceed 850℃, considering the service conditions of the heat pipe reactor. In different embodiments, different ways of heating can be adopted: in some embodiments, the heat pipe inserted into the grid matrix 1 can be heated; in other embodiments, the grid matrix 1 can be heated as a whole from the outside by an electric heating device; in some embodiments, the heat pipe reactor can be started after all the pipes 2 are completely inserted, and the grid matrix 1 is heated by the heat generated by the fuel rods.

[0040] In a comparative example, the existing process can control the assembly gap between the grid matrix and the pipe to about 100 μm without using the filling slurry. The heat transfer test is carried out by heating the heat pipe with an electric heating rod, and it is measured that when the temperature of the grid matrix is 800℃, the temperature of the heat pipe is 1226.7℃, and the temperature difference is 426.7℃. This data is used as a reference benchmark to evaluate the heat transfer capacity of the heat pipe reactor.

[0041] In the first preferred embodiment, cork is used as end plug to seal the bottom of the mounting hole; iron powder with an average particle size of 20 μm and nickel powder with an average particle size of 10 μm are mixed as the heat-conducting powder in a weight ratio of 1:1, and ethanol is used as the dispersant to obtain a filling slurry with a solid content of about 85%; about 5 g of the filling slurry is poured into each mounting hole, and then the heat pipe is inserted into the mounting hole, so that the filling slurry is forced to flow to completely fill the assembly gap and partially overflow from the top of the mounting hole; after the overflowed filling slurry is cleaned, the grid substrate is heated by an external heating device, and the filling slurry is fully cured at 200°C for 3 h; the cork is removed, and non-destructive testing is performed by industrial CT to confirm that the filling slurry is fully filled and free of pores and gaps inside. The heat pipe is heated by an electric heating rod, and it is measured that when the temperature of the grid substrate is 800°C, the temperature of the heat pipe is 925.8°C, and the temperature difference is 125.8°C.

[0042] In the second preferred embodiment, cork is used as end plug to seal the bottom of the mounting hole; copper powder with an average particle size of 15 μm is used as the heat-conducting powder, and ethanol, ethylene glycol and an organic thickening agent are used as the dispersant to obtain a filling slurry with a solid content of about 80%; about 5 g of the filling slurry is poured into each mounting hole, and then the heat pipe is inserted into the mounting hole, so that the filling slurry is forced to flow to completely fill the assembly gap and partially overflow from the top of the mounting hole; after the overflowed filling slurry is cleaned, the grid substrate is heated by an external heating device, and the filling slurry is fully cured at 150°C for 5 h; the cork is removed, and non-destructive testing is performed by industrial CT to confirm that the filling slurry is fully filled and free of pores and gaps inside. The heat pipe is heated by an electric heating rod, and it is measured that when the temperature of the grid substrate is 800°C, the temperature of the heat pipe is 833.6°C, and the temperature difference is 33.6°C.

[0043] In one comparative example, the heat pipe is first inserted into the mounting hole of the vertically placed lattice base; then copper powder with an average particle size of 15 μm is used as the heat-conducting powder, and ethanol, ethylene glycol and an organic thickening agent are used as the dispersing agent to mix a filling slurry with a solid content of about 80%; the filling slurry is injected into the assembly gap from the end of the mounting hole, and the filling slurry is filled into the assembly gap under the action of injection pressure and gravity until it overflows from the bottom end of the mounting hole; the overflowing filling slurry is cleaned, and the lattice base is heated as a whole to 150°C for 5 h to allow the filling slurry to fully solidify. Non-destructive testing is performed using industrial CT, and it is found that there are obvious bubbles and pores in the filling slurry at the lower end, indicating that the filling slurry cannot flow sufficiently only by relying on the action of injection pressure and gravity. The heat pipe is heated using an electric heating rod, and it is found that when the temperature of the lattice base at the top end is 800°C, the temperature of the heat pipe is 875.3°C; and when the temperature of the lattice base at the bottom end is 800°C, the temperature of the heat pipe is 966.7°C. It can be seen that the heat transfer effect between the heat pipe and the lattice base in the comparative example is significantly different from that in the second preferred embodiment, and at the same time, due to the insufficient filling of the filling slurry in the assembly gap, the heat transfer effect in the region at the bottom end is seriously deteriorated, resulting in obvious non-uniform heat conduction in the axial direction of the heat pipe, which affects the efficiency and safety margin of the reactor.

[0044] Embodiments of another aspect of the present application provide a heat pipe type reactor manufactured using the assembly method of the heat pipe type reactor provided in any of the preceding embodiments. Since the forced flow form is used to promote the sufficient filling of the filling slurry in the assembly gap, the solid-state heat transfer efficiency of the reactor can be effectively improved, and the safety margin of the reactor can be further improved.

[0045] Some existing heat pipe type reactor schemes use a method of directly attaching a coating, a film or the like solid material to the pipe and then assembling, which causes the friction between the lattice base and the pipe during the assembly process to easily cause damage to the heat transfer layer, and the scratches and debris generated by the peeling further affect the heat transfer efficiency at the contact interface during the service process. Since the reactor provided in the embodiments of the present application uses the assembly method of first filling the fluid filling slurry and then heating and solidifying, the heat pipe and the base hardly have relative displacement after the filling slurry is solidified, which can effectively avoid mechanical damage caused by friction. At the same time, since the solidified filling slurry is used for heat transfer, a slightly large assembly gap can be reserved between the key and the mounting hole of the lattice base, thereby also reducing the assembly difficulty.

[0046] And because the forced flow is used to promote the uniform distribution of the filling slurry in the assembly gap, the assembly gap between the pipe (heat pipe and fuel rod) and the grid base can be fully filled, effectively avoiding the appearance of bubbles and pores, ensuring the uniformity of the axial heat transfer performance, improving the uniformity of the core temperature, preventing local overheating caused by poor local heat conduction, reducing thermal stress caused by long-term service, effectively improving the safety margin of the heat pipe type reactor, and improving the reliability of the long-term service of the heat pipe type reactor.

[0047] The above embodiments are intended to further illustrate the present application in conjunction with the accompanying drawings, so that those skilled in the art can understand the technical concept of the present application. Within the scope of the present application, optimization or equivalent replacement of the method steps involved, and combination of the embodiments in different embodiments without structural and principle conflicts, all fall within the protection scope of the present application.

Claims

1. A method for assembling a heat pipe reactor, the heat pipe reactor comprising a grid substrate and tubing, the grid substrate including mounting holes for mounting the tubing, the tubing comprising heat pipes and fuel rods, characterized in that, Includes the following steps: Step a): A plug is provided at one end of the mounting hole of the grid substrate to seal it, and the grid substrate is arranged vertically so that the end with the plug is located at the bottom; Step b): Inject a filling slurry into the mounting hole, the filling slurry comprising thermally conductive powder and a dispersant; Step c): Insert the pipe fitting along the mounting hole, so that the filling slurry fills the gap between the mounting hole and the pipe fitting and overflows from the top of the mounting hole; Step d): Remove the overflowing filler slurry, heat and keep the grid substrate at a certain temperature to solidify the filler slurry.

2. The assembly method of the heat pipe reactor according to claim 1, characterized in that, The gap between the mounting hole and the pipe fitting is 50μm-500μm.

3. The assembly method of the heat pipe reactor according to claim 1 or 2, characterized in that, In step b), the viscosity of the filling slurry is 800 Pa·s-1200 Pa·s, and the yield strength is 180 Pa-230 Pa.

4. The assembly method of the heat pipe reactor according to claim 3, characterized in that, In step b), the thermally conductive powder includes one or a combination of copper powder, iron powder, chromium powder, molybdenum powder, and nickel powder; the dispersant includes one or a combination of ethanol, ethylene glycol, phosphate, and silicate; and the solid content of the filler slurry is 70%-90%.

5. The assembly method of the heat pipe reactor according to claim 1 or 2, characterized in that, In step d), the heating temperature shall not exceed 850°C.

6. The assembly method of the heat pipe reactor according to claim 5, characterized in that, In step d), the heating method is to use an external heat source to heat the heat pipe.

7. The assembly method of the heat pipe reactor according to claim 5, characterized in that, In step d), the heating method is to directly heat the grid substrate using an electric heating rod.

8. The assembly method of the heat pipe reactor according to claim 5, characterized in that, In step d), the heating method is to start the heat pipe reactor and use the fuel rods to heat the grid substrate.

9. The assembly method of the heat pipe reactor according to claim 1 or 2, characterized in that, Step d) further includes a step of using CT to detect the gap filling degree after sintering.

10. A heat pipe reactor, comprising a grid substrate, heat pipes, and fuel rods, characterized in that, The reactor is assembled using the assembly method for the heat pipe reactor as described in any one of claims 1 to 9.

Images