A flat plate and tube combined divertor cooling module and its preparation method

Abstract

The present invention discloses a flat plate and through-tube combined divertor cooling module and its preparation method, comprising: a tungsten block, a substrate, an oxygen-free copper layer, a heat sink, and a cooling water pipe; an oxygen-free copper layer is processed on the inner wall of the tungsten block to form a tungsten-copper block; the tungsten-copper block is connected to the heat sink; the heat sink is connected to the substrate; and the substrate is connected to the cooling water pipe, with the cooling water pipe adopting a one-in, one-out arrangement. The "saddle-shaped" tungsten-copper block produced by the present invention can prevent the tungsten and tungsten-copper sheets from falling off, meeting the function of a through-tube module and saving half of the tungsten material. The "saddle-shaped" tungsten-copper block is processed through a mold, and the thickness of the tungsten block can be easily increased in the middle thickness direction, which helps to reduce the maximum temperature difference and maximum thermal stress of the tungsten-copper block. At the same time, the tungsten block structure on the side can better protect the side from the transient heat flow of the plasma, thereby significantly improving the service life of the combined structure.

Description

Technical Field

[0001] The present invention relates to the field of nuclear fusion, and in particular to a flat plate and tube combined divertor cooling module and a preparation method thereof. Background Art

[0002] The divertor is the core component of the nuclear fusion tokamak device, directly facing the impact of strong particle flow and high-temperature heat flow. As an ultra-high heat load component of the device, the divertor's heat load removal capability is the most core technical evaluation indicator. Major international fusion experimental devices, such as the International Thermonuclear Experimental Reactor (ITER), the EAST (East Super Torus), France's WEST and Japan's JT-60SA, as well as major fusion reactor devices such as the EU's EU-DEMO, Japan's JA-DEMO and South Korea's K-DEMO, all have divertor heat load removal capabilities designed to withstand a steady-state 10 MW / m 2 The stronger the divertor's heat load removal capability is, the more conducive it is to maintaining a high-confinement plasma steady-state operation, which is crucial for achieving efficient fusion reactions. For the China Fusion Engineering Test Reactor (CFETR), the divertor needs to be able to withstand a steady-state load of 20 MW / m 2 capacity, but further improvement is limited by the current level of divertor engineering technology.

[0003] Monoblock and flat tile are the two basic cooling modules for divertor. The following introduces the two basic module structures using the materials currently used in fusion experimental devices as an example. Figure 1 As shown: The through-tube module uses chromium zirconium copper water pipes to connect tungsten blocks in series. A layer of oxygen-free copper material is laid between the water pipes and the tungsten to serve as a thermal stress relief layer connecting the two metals. The through-tube type has high thermal stability and structural strength and is used in major fusion experimental devices and fusion reactor devices. It can withstand steady-state 10 MW / m 2 Heat load. Flat type modules such as Figure 2 As shown: a rectangular tungsten sheet of a certain thickness is directly compounded with a chromium-zirconium-copper heat sink under the transition of a layer of oxygen-free copper as a thermal stress buffer layer, and a cooling channel is opened inside the heat sink to remove heat. Compared with the tube-type module, the flat-plate module has a stronger heat exchange capacity and a lower production cost. In 2021, the high heat load area of ​​the EAST divertor was the first to use flat-plate modules instead of tube-type modules; the CFETR divertor all uses flat-plate modules, and the design and pre-research have verified that it can withstand a steady-state 20 MW / m 2 Heat load.

[0004] In the existing technology, through-tube modules are more reliable than flat-plate modules. There is generally no risk of tungsten string disintegration, resulting in the exposure of chromium-zirconium-copper and adjacent tungsten string side parts to the plasma. However, this module configuration has limited ability to withstand high thermal loads. As the thermal load increases, although there is no obvious damage on the module surface, if the temperature exceeds the allowable value of the copper transition layer, it may cause the copper layer to melt, further leading to heat transfer failure in a single part and thus module damage. In addition, when the cooling water in the tube faces a critical heat flux, a phase transition will occur, and the water pipe itself is at risk of burning through and leaking. Since the EAST divertor upgrade in 2021, internal water pipe ruptures have been observed on the tungsten string target plate, resulting in serious consequences such as experimental shutdown and maintenance. Although flat-plate modules can withstand high thermal loads, the thermomechanical stability of the tungsten sheet and heat sink is relatively insufficient during actual service, resulting in warping and cracking of the tungsten sheet, and in severe cases, even the tungsten-copper sheet falling off. These phenomena all restrict the stable operation of the fusion reactor core. Summary of the Invention

[0005] In order to solve the above technical problems, the present invention combines the advantages of the two modules. By combining the tube-through type and flat-plate type modules, it not only combines the advantages of both, but also meets the steady-state 20 MW / m 2 Under high heat load conditions, it can prevent the tungsten sheet and tungsten copper sheet from falling off, thus improving the reliability of the combined structure. It is particularly helpful to reduce the temperature difference of the tungsten copper sheet and reduce thermal stress, thereby significantly improving the service life of the combined structure.

[0006] The present invention provides a flat plate and tube combined divertor cooling module, comprising: a tungsten block, a substrate, an oxygen-free copper layer, a heat sink, and a cooling water pipe; the oxygen-free copper layer is processed on the inner wall of the tungsten block to form a tungsten-copper block; the tungsten-copper block is connected to the heat sink; the heat sink is connected to the substrate; the substrate is connected to the cooling water pipe, and the cooling water pipe adopts a one-inlet and one-outlet arrangement.

[0007] Compared with the prior art, the beneficial effects of the present invention are embodied in:

[0008] (1) In view of the shortcomings of the existing technology, the "saddle-shaped" tungsten copper block made by the present invention can prevent the tungsten sheet and tungsten copper sheet from falling off, meeting the function of the through-tube module and saving half of the tungsten material. At the same time, the heat load it can withstand reaches the steady-state 20 MW / m of the flat-plate module. 2 , the reliability of the combined structure is improved without reducing the heat load, and the performance as a high heat load module of the divertor is even better.

[0009] (2) Both the through-tube module and the flat-plate module have two corner temperatures higher than the middle temperature. The "saddle-shaped" tungsten copper block produced by the present invention is processed by a mold, and the thickness of the tungsten block can be easily increased in the middle thickness direction, thereby increasing the temperature of the middle area. The finite element analysis results show that the curved surface design helps to reduce the maximum temperature difference of the tungsten copper block and reduce the maximum thermal stress. At the same time, the tungsten block structure on the side can better protect the side from the transient heat flow of the plasma, thereby significantly improving the service life of the combined structure.

[0010] (3) The "saddle-shaped" tungsten-copper block prepared by the present invention increases the bonding area between tungsten and oxygen-free copper. The oxygen-free copper surface laser array treatment process adopted improves the surface adsorption of the brazing liquid. The vacuum baking and nano-coating processes adopted obtain an extremely high-quality oxygen-free copper welding surface. The coating process and vacuum encapsulation tooling adopted obtain a high-quality welding interface, which improves the overall connection quality of the bonding surface. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0012] Figure 1 This is a schematic diagram of the original tungsten string divertor cooling module;

[0013] Figure 2 This is a schematic diagram of the original flat-plate divertor cooling module;

[0014] Figure 3 A schematic diagram of a flat plate and tube-type combined divertor cooling module;

[0015] Figure 4 Schematic diagram of a single tungsten copper block;

[0016] Figure 5 This is a quarter-section isometric view of the composite heat sink;

[0017] Figure 6 It is a cross-sectional view of the internal channel of the cooling module;

[0018] Figure 7 This is a cross-sectional view of the internal channel of the cooling module of Example 2;

[0019] Figure 8 (a) is a schematic diagram of the cooling module of Example 3;

[0020] Figure 8 (b) is a cross-sectional view of the internal channel of the cooling module of Example 3;

[0021] Figure 9 The figure is a flow chart of a method for preparing a flat plate and tube-through-tube combined divertor cooling module.

[0022] Figure numerals: 1, tungsten block; 2, oxygen-free copper block; 3, heat sink; 4, substrate; 5, cooling water pipe; 6, tungsten copper block; 7, fin. DETAILED DESCRIPTION

[0023] In order to make the objectives, technical solutions, and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are intended only to illustrate the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other. To achieve the above-mentioned objectives, the present invention adopts the following technical solutions.

[0024] Example 1

[0025] The embodiment of the present invention provides a flat plate and tube combined divertor cooling module, see Figure 3 As shown, the device comprises a tungsten block 1, an oxygen-free copper layer 2, a heat sink 3, a substrate 4, and a cooling water pipe 5. The inner wall of the tungsten block 1 is provided with the oxygen-free copper layer 2. The tungsten block 1 is connected to the heat sink 3, and the oxygen-free copper layer 2 is in contact with the heat sink 3. The heat sink 3 is connected to the substrate 4. The substrate 4 is connected to the cooling water pipe 5, which is arranged in a one-inlet, one-outlet configuration.

[0026] Furthermore, the tungsten block 1 and the oxygen-free copper layer 2 form a tungsten copper block 6. Figure 4 Shown, including:

[0027] The tungsten copper block 6 directly faces the plasma and is designed to be saddle-shaped;

[0028] The tungsten block 1 is made of tungsten, a thermally protective material, and is designed to be saddle-shaped. The overall height of the tungsten block is approximately half the size of the original tungsten string-type tungsten block. The surface that mates with the oxygen-free copper layer 2 in the internal height direction is a curved plane. The projection of the curved surface is an arc with a radius of 195mm. The thickness of the tungsten block 1 in the height direction increases continuously from a minimum of 5mm on both sides to the middle. The overall length of the tungsten block 1 is approximately twice the size of the original tungsten string-type tungsten block, with an outer length of 50mm and a side thickness of 2mm. The bottom is designed as a 1mm convex strip structure that can be stuck in the groove of the heat sink 3 and slide during assembly. After connection, it can function in the same manner as the original tungsten string module to prevent the tungsten copper block 6 from falling off. The width of the tungsten block 1 remains unchanged at 11.5mm, and the spacing between each tungsten block is 0.25mm in the 1-degree direction of width.

[0029] The oxygen-free copper layer 2 is made of copper, a thermal stress buffer material, and is designed in a saddle shape. Located on the inner surface of the tungsten block 1, it has an overall thickness of 1 mm and a curved mating surface with a projected arc radius of 196 mm. The top mating surface has a 1 mm fillet.

[0030] Furthermore, the heat sink 3 is made of copper alloy material, and the base 4 is made of stainless steel material, and the heat sink 3 and the base 4 are connected to form a composite heat sink. Figure 5 As shown, the composite heat sink has an internal cooling channel, with fins 7 positioned at the top of the channel as a turbulent super-vaporization structure to enhance heat transfer. The fins 7 have equal bottom heights, decreasing in height from a maximum of 9mm on either side toward the center. A 1mm radius is provided between the fin root and the channel's upper surface, creating a curved surface with a 200mm radius. The fin sides are inclined, parallel to the wall surface and spaced 2mm apart. The fin width remains unchanged at 2.2mm, with each fin spaced 7.5mm apart across its width.

[0031] The side surface of the cooling channel is an oblique plane. Figure 6 As shown, by appropriately beveling while ensuring the thickness of the side wall, the heat exchange surface of the cooling channel can be increased; the distance between the cooling channel and the two vertex corners of the tungsten block can be reduced, thereby reducing the temperature difference inside the tungsten block 1 and reducing thermal stress.

[0032] The present invention also provides a method for preparing a flat plate and tube combined divertor cooling module. Figure 9 As shown, the following steps are included:

[0033] The "saddle-shaped" tungsten copper block 6 is made from the tungsten block 1 and the oxygen-free copper layer 2 machined on the inner wall of the tungsten block 1. First, a dense "saddle-shaped" tungsten block 1 is formed using powder metallurgy or mechanical alloying technology. Next, oxygen-free copper is melted and cast onto the inner surface of the tungsten block 1 through a mold. Vacuum heat treatment and hot isostatic pressing processes are performed to improve the bonding interface quality, forming a denser tungsten copper block 6. Then, wire cutting or milling is used to machine the inner surface of the oxygen-free copper layer 2 to the desired size.

[0034] Furthermore, a laser array treatment process creates a dense array of micron-sized pores on the surface of the oxygen-free copper layer 2, preventing the loss of solder liquid from the surface during brazing. Before welding, the layer undergoes a 350°C vacuum bake followed by a metallic chromium nanocoating process for surface treatment and activation, promoting the expulsion of surface gases and eliminating or minimizing the effects of pores, resulting in an extremely high-quality oxygen-free copper weld surface.

[0035] A composite heat sink is fabricated by connecting the heat sink 3 to the substrate 4. The heat sink material is a precipitation-strengthened copper alloy (CuCrZr) or a dispersion-strengthened copper alloy (ODS-Cu). The substrate structural material is 316L or low-activation steel. First, the heat sink 3 and substrate 4 are explosively welded to form the composite heat sink. Next, the composite heat sink is cut to the desired size using wire cutting or milling, leaving a certain machining allowance. Finally, grooves are machined into the sides of the composite heat sink to secure the heat sink's snap-on connection.

[0036] Furthermore, before explosive welding, the surfaces of the heat sink 3 and the substrate 4 are coated, and during welding, a flexible sealing sheath is used and vacuum is drawn to remove the air adsorbed on the surface of the explosive welding material, reduce the influence of the surface gas, and obtain a high-quality welding interface.

[0037] The combined cooling module is formed by connecting the tungsten copper blocks 6 and the composite heat sink. First, the required number of tungsten copper blocks 6 are slid into the composite heat sink, and the connection surfaces are assembled into place. Next, they are connected by vacuum brazing. The cooling channels and fins 7 are then machined from the bottom of the module. The base structure is then machined into place, and finally, the cooling water pipes 5 are welded.

[0038] Example 2

[0039] The assembly structure of this embodiment is different from that of the first embodiment. The inner height direction of the tungsten block 1 and the matching surface of the oxygen-free copper layer 2 are straight planes. The tungsten copper block 6 also maintains a straight plane design. At the same time, the cooling channel inside the heat sink 3 maintains a "saddle shape". The upper wall of the cooling channel is thick in the middle and thin on both sides. This embodiment is designed as a stepped plane. The cross-sectional diagram is shown as follows Figure 7 The stepped structure increases the heat exchange area with the cooling water and, to a certain extent, widens the heat transfer path in the middle area. While maintaining the sidewall thickness, the channel sidewalls are appropriately deepened to match the groove structure of the heat sink's outer wall. This reduces the heat transfer path at the top corners of the tungsten block 1, lowering the temperature difference within the block 1 and reducing thermal stress.

[0040] Furthermore, the rest is the same as the above-mentioned embodiment 1.

[0041] Example 3

[0042] Figures 8(a) and 8(b) show the schematic and cross-sectional views of the assembly structure of this embodiment. The localized snap-in structure with vertical corners on either side of the tungsten copper block 6 is replaced with an integrated snap-in structure with beveled side angles. The outer side of the heat sink 3 is inscribed with an inwardly angled groove, matching the inner bevel angle of the heat sink, maintaining a uniform sidewall thickness. The inner bevel angles of the tungsten copper block 6 are the same as the heat sink's side angles, and the oxygen-free copper sheet maintains a uniform thickness of 1mm. This structure is simpler and reduces the number of corners.

[0043] Furthermore, the rest is the same as the above-mentioned embodiment 1.

[0044] The above description is only a preferred embodiment of the present invention and is not intended to limit the invention. For those skilled in the art, the embodiments of the present invention may have various changes and variations. Any modifications, replacements, 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 flat plate and tube combined divertor cooling module, characterized in that: include: Tungsten block, substrate, oxygen-free copper layer, heat sink and cooling water pipe; the oxygen-free copper layer is processed on the inner wall of the tungsten block to form a tungsten copper block; the tungsten copper block is connected to the heat sink; the heat sink is connected to the substrate; the substrate is connected to the cooling water pipe, and the cooling water pipe adopts a one-in-one-out arrangement; The tungsten copper block is designed to be saddle-shaped. The inner height of the tungsten block and the matching surface with the oxygen-free copper layer are not straight planes, but curved or folded surfaces, so that the height of the tungsten block increases from both sides to the middle. The bottom of the tungsten copper block is designed as a convex strip structure, which is snapped into the groove on the side of the heat sink.

2. The flat plate and tube combined divertor cooling module according to claim 1, characterized in that: The oxygen-free copper layer is bonded to the inner surface of the tungsten block, the thickness of the oxygen-free copper layer is 1-2 mm, and a rounded corner is set on the top mating surface.

3. The flat plate and tube combined divertor cooling module according to claim 1, characterized in that: The heat sink is made of copper alloy material, the base is made of stainless steel, and the heat sink and the base are connected to form a composite heat sink; a cooling flow channel is provided inside the composite heat sink, and fins are provided on the top of the flow channel.

4. The flat plate and tube combined divertor cooling module according to claim 3, characterized in that: The height of the fins decreases from both sides to the middle, the side surfaces of the fins are inclined, and are parallel to the wall surface with a spacing of 2-4 mm. The fin width remains unchanged at 2-4 mm, and the spacing between each fin in the width direction is 5-10 mm.

5. A method for preparing a flat plate and tube combined divertor cooling module, characterized in that: The following steps are involved: Make a "saddle-shaped" tungsten copper block and process the oxygen-free copper layer inside the tungsten block to form a tungsten copper block; making a composite heat sink, formed by connecting the heat sink and a substrate; Making a combined cooling module, which is formed by connecting the tungsten copper block, the composite heat sink and the cooling water pipe; The composite heat sink side surface is processed with grooves to position the heat sink buckle connection surface; Slide a certain number of tungsten copper blocks into the composite heat sink, assemble the connection surfaces in place, and connect them by vacuum brazing; process the cooling flow channel and fin structure inside the composite heat sink, and weld the cooling water pipes; The bottom of the tungsten copper block is designed as a convex strip structure, which is snap-fitted with the groove on the side of the heat sink.

6. The method for preparing a flat plate and tube-through-tube combined divertor cooling module according to claim 5, characterized in that: The tungsten block is made of pure tungsten or tungsten alloy, and is formed into a "saddle-shaped" tungsten block by powder metallurgy or mechanical alloying. The tungsten-copper block is made by casting oxygen-free copper onto the inner surface of the tungsten block through a mold, and is formed into a tungsten-copper block through vacuum heat treatment and hot isostatic pressing. The tungsten-copper block is processed to the desired size of the inner surface of the oxygen-free copper layer by wire cutting or milling. The tungsten-copper block uses a laser array processing process to form a micron-level micropore array on the surface of the oxygen-free copper layer, thereby improving the surface adsorption of the brazing liquid. Before welding, the tungsten-copper block is vacuum baked and nano-coated to obtain an oxygen-free copper welding surface.

7. The method for preparing a flat plate and tube-through-tube combined divertor cooling module according to claim 6, characterized in that: Precipitation-strengthened copper alloy CuCrZr or dispersion-strengthened copper alloy ODS-Cu is selected as the heat sink material, 316L or low-activation steel is selected as the base structural material, and explosive welding is used to weld the heat sink and the base into a composite heat sink; before explosive welding, the surfaces of the heat sink and the base plate are subjected to a coating process, and vacuum encapsulation tooling is used during welding to obtain a welding interface.

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