Flat plate and through pipe combined divertor cooling module and preparation method thereof

Abstract

The invention discloses a flat plate and penetrating pipe combined type divertor cooling module and a preparation method. The flat plate and penetrating pipe combined type divertor cooling module comprises a tungsten block, a base body, an oxygen-free copper layer, a heat sink and a cooling water pipe. Processing an oxygen-free copper layer on the inner wall of the tungsten block to form a tungsten copper block; the tungsten copper block is connected with the heat sink; the heat sink is connected with the base body; the base body is connected with the cooling water pipe, and the cooling water pipe is arranged in a one-inlet and one-outlet mode. According to the saddle-shaped tungsten copper block manufactured through the method, the tungsten sheet and the tungsten copper sheet can be prevented from falling off, the function of a pipe penetrating type module is met, a half of tungsten material is saved, the saddle-shaped tungsten copper block is machined through a mold, the thickness of the tungsten block can be conveniently increased in the middle thickness direction, the maximum temperature difference of the tungsten copper block can be reduced, and the maximum thermal stress of the tungsten copper block can be reduced; and meanwhile, the tungsten block structure on the side surface can better protect the side surface from bearing a plasma transient heat flow, so that the service life of the combined structure is remarkably prolonged.

Description

Technical Field

[0001] The invention relates to the field of nuclear fusion, and in particular to a flat plate and tube-through-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, which directly faces 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 capacity is the most core technical evaluation indicator. The major international fusion experimental devices, such as the International Thermonuclear Experimental Reactor (ITER), the Eastern Super Torus (EAST), 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 capacity designs that can 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 20 MW / m 2 capacity, but further improvement is limited by the current level of divertor engineering technology.

[0003] Monoblock and Flat Tile are two basic cooling modules for divertor. The following introduces the two basic module structures by taking 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, and a layer of oxygen-free copper material is laid between the water pipes and tungsten 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-plate 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 take away the heat. Compared with the tube-through 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-through 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 prior art, the through-tube type module is more reliable than the flat-plate type module, and generally there is no risk of the tungsten string disintegrating, causing the chromium-zirconium-copper and adjacent tungsten string side parts to be exposed to the plasma, but this module configuration has limited bearing capacity for high heat loads. With the increase of heat load, although there is no obvious damage on the surface of the module, if the temperature exceeds the allowable value of the copper transition layer, the copper layer may melt, further leading to heat transfer failure in a single part and module damage; in addition, when the cooling water in the tube faces the critical heat flow, there will be a phase transition, and the water pipe itself is at risk of being burned through and leaking. Since the upgrade and transformation of the lower divertor of EAST in 2021, internal water pipe ruptures have been observed on the tungsten string target plate, resulting in serious consequences of experimental shutdown maintenance. Although the flat-plate module bears a high heat load, the thermomechanical stability of the tungsten sheet and the heat sink is relatively insufficient during actual service, showing that the tungsten sheet is warping and cracking, and in severe cases, it may even cause the tungsten copper sheet to fall off. These phenomena restrict the steady-state 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 the flat-plate type modules, the advantages of both modules are combined into one. 2 Under high heat load, it can prevent the tungsten sheet and tungsten copper sheet from falling off, thus improving the reliability of the combined structure; more importantly, it helps to reduce the temperature difference of the tungsten copper sheet and reduce thermal stress, thus 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-in-one-out arrangement.

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

[0008] (1) In view of the shortcomings of the prior art, the "saddle-shaped" tungsten copper block produced by the present invention can prevent the tungsten sheet and the tungsten copper sheet from falling off, meet the function of the through-tube module and save half of the tungsten material. At the same time, the heat load it withstands 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 its performance as a high heat load module of the divertor is even better.

[0009] (2) Both the through-tube type module and the flat type 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 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.

[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 connection quality of the bonding surface as a whole. 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-through combined divertor cooling module;

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

[0016] Figure 5 It is a quarter-cut axonometric view of the composite heat sink;

[0017] Figure 6 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] FIG8 (a) is a schematic diagram of a cooling module of Embodiment 3;

[0020] FIG8( b ) is a cross-sectional view of the internal channel of the cooling module of the third embodiment;

[0021] Fig. 9 The present invention is a schematic 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 purpose, technical scheme and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in each embodiment of the present invention described below can be combined with each other as long as they do not conflict with each other. To achieve the above-mentioned purpose, the present invention adopts the following technical scheme.

[0024] Embodiment 1

[0025] The embodiment of the present invention provides a flat plate and tube combined divertor cooling module, Figure 3 As shown, it includes: 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 an 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, and the cooling water pipe 5 adopts a one-in-one-out arrangement.

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

[0027] The tungsten copper block 6 directly faces the plasma, and its shape is designed to be a "saddle shape";

[0028] The tungsten block 1 is made of thermal protection material tungsten, and its shape is designed to be "saddle-shaped". The overall height of the tungsten block is about half the size of the original tungsten string-type tungsten block. The mating surface 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 the minimum of 5mm on both sides to the middle. The overall length of the tungsten block 1 is about 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 convex strip structure with a convex strip of 1mm. It can be stuck in the groove of the heat sink 3 and slide during assembly. After connection, it can be consistent with the function of the original tungsten string module to prevent the tungsten copper block 6 from falling off. The width of the tungsten block 1 remains unchanged, with a width of 11.5mm, and the spacing of each tungsten block in the 1 degree direction of width is 0.25mm.

[0029] The oxygen-free copper layer 2 is made of thermal stress buffer material copper and is designed to be "saddle-shaped". The oxygen-free copper layer 2 is located on the inner surface of the tungsten block 1, with an overall thickness of 1 mm, a matching surface that is a curved plane, a radius of the curved surface projection arc of 196 mm, and a 1 mm fillet on the top matching surface.

[0030] Furthermore, the heat sink 3 is made of copper alloy material, and the substrate 4 is made of stainless steel material, and the heat sink 3 and the substrate 4 are connected to form a composite heat sink. Figure 5 As shown, the composite heat sink is provided with a cooling channel inside, and a fin 7 is provided on the top of the channel as a turbulent super vaporization structure to enhance heat transfer. The bottom of the fin 7 is of equal height, and the fin height decreases from a maximum of 9mm on both sides to the middle. A 1mm chamfer is provided between the root of the fin and the upper surface of the channel. The internal channel is a curved plane with a bending radius of 200mm. The side of the fin is an inclined surface, parallel to the wall surface and maintaining a spacing of 2mm. The fin width remains unchanged, with a width of 2.2mm, and the spacing in the width direction of each fin is 7.5mm.

[0031] The side surface of the cooling channel is an oblique plane. Figure 6 As shown, by appropriately chamfering 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, the temperature difference inside the tungsten block 1 can be reduced, and the thermal stress can be reduced.

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

[0033] The "saddle-shaped" tungsten copper block 6 is made of the tungsten block 1 and the oxygen-free copper layer 2 processed on the inner wall of the tungsten block 1. First, a dense "saddle-shaped" tungsten block 1 is formed by powder metallurgy or mechanical alloying technology; then, oxygen-free copper is melted and cast onto the inner surface of the tungsten block 1 through a mold, and the quality of the bonding interface is improved through vacuum heat treatment and hot isostatic pressing processes to form a denser tungsten copper block 6; then, the inner surface size of the oxygen-free copper layer 2 is processed in place by wire cutting or milling.

[0034] Furthermore, a laser array treatment process is used to form a dense micron-level micropore array on the surface of the oxygen-free copper layer 2, which can prevent the solder liquid from losing from the surface during brazing. Before welding, it is vacuum-baked at 350 degrees, and then the surface is treated and activated using a metal chromium nano-coating process to promote the discharge of surface gas, eliminate or reduce the impact of pores, and obtain a very high-quality oxygen-free copper welding surface.

[0035] A composite heat sink is made by connecting the heat sink 3 with the substrate 4. The heat sink material is selected as precipitation-strengthened copper alloy CuCrZr or dispersion-strengthened copper alloy ODS-Cu. The substrate structure material is selected as 316L or low-activated steel. First, the heat sink 3 and the substrate 4 are welded into a composite heat sink by explosion welding; then the composite heat sink is cut to the required size by wire cutting or milling with a certain processing allowance; finally, a groove is processed on the side of the composite heat sink to process the heat sink buckle connection surface in place.

[0036] Furthermore, before explosion 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 explosion welding material, reduce the influence of the surface gas, and obtain a high-quality welding interface.

[0037] The combined cooling module is made by connecting the tungsten copper block 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 surface is assembled in place; then vacuum brazing is used to connect; then the cooling channel and fin 7 structure are processed from the bottom of the module; then the base structure is processed in place, and finally the cooling water pipe 5 is welded.

[0038] Embodiment 2

[0039] The assembly structure of this embodiment is different from that of the first embodiment. The mating surface of the tungsten block 1 and the oxygen-free copper layer 2 in the height direction is a straight plane, and 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 schematic diagram is shown in FIG. Figure 7 The stepped structure increases the heat exchange area with the cooling water and increases the heat transfer path in the middle area to a certain extent; the side wall of the flow channel is appropriately deepened to reduce the heat transfer path at the top corners on both sides of the tungsten block 1, reduce the temperature difference inside the tungsten block 1, and reduce thermal stress while maintaining the thickness of the side wall and cooperating with the groove structure of the outer wall of the heat sink.

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

[0041] Embodiment 3

[0042] The schematic diagram and cross-sectional diagram of the assembly structure of this embodiment are shown in Figures 8 (a) and 8 (b). The local buckle structure of the vertical corners on both sides of the tungsten copper block 6 is cancelled, and the side angled overall buckle structure is replaced: the outer side of the heat sink 3 is inscribed with an oblique groove, which is consistent with the inner bevel of the heat sink to keep the side wall thickness uniform; the inner bevel of both sides of the tungsten copper block 6 is the same as the bevel of the side of the heat sink, and the thickness of the oxygen-free copper sheet is kept uniform at 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 modification, replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope 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 setting.

2. A flat plate and tube combined divertor cooling module according to claim 1, characterized in that: The shape of the tungsten copper block is designed to be "saddle-shaped". The inner height direction of the tungsten block and the matching surface with the oxygen-free copper layer are not designed as straight planes, but curved or folded surfaces, so that the height of the tungsten block increases continuously from both sides to the middle; the bottom of the tungsten copper block is designed as a convex strip structure, which is buckled with the groove on the side of the heat sink.

3. A flat plate and tube combined divertor cooling module according to claim 2, 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.

4. 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 substrate is made of stainless steel material, and the heat sink and the substrate are connected to form a composite heat sink; a cooling flow channel is arranged inside the composite heat sink, and a fin is arranged on the top of the flow channel.

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

6. A method for preparing a flat plate and tube-through 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 with a substrate; A combined cooling module is manufactured, which is formed by connecting the tungsten copper block, the composite heat sink and the cooling water pipe.

7. The method for preparing a flat plate and tube-through-tube combined divertor cooling module according to claim 6, characterized in that: The tungsten block material is pure tungsten or tungsten alloy, and a "saddle-shaped" tungsten block is formed by powder metallurgy or mechanical alloying. The tungsten-copper block is made by melting 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 is processed by laser array processing to form a micron-level micropore array on the surface of the oxygen-free copper layer to improve the surface adsorption of the brazing liquid. Before welding, the tungsten-copper block is subjected to vacuum baking and nano-coating processes to obtain an oxygen-free copper welding surface.

8. The method for preparing a flat plate and tube-through combined divertor cooling module according to claim 7, 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 matrix structural material, and the heat sink and the matrix are welded into a composite heat sink by explosive welding; before explosive welding, the surface of the heat sink and the matrix plate is subjected to a coating process, and a vacuum jacket tooling is used during welding to obtain a welding interface.

9. The method for preparing a flat plate and tube-through combined divertor cooling module according to claim 8, characterized in that: The composite heat sink has grooves machined on its side surface, and the heat sink buckle connection surface is machined in place.

10. The method for preparing a flat plate and tube-through combined divertor cooling module according to claim 9, characterized in that: A certain number of tungsten copper blocks are slid into the composite heat sink, the connection surfaces are assembled in place, and connected by vacuum brazing; cooling channels and fin structures are processed inside the composite heat sink, and cooling water pipes are welded.

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