Tritium-compatible cryopump cold plate, preparation method thereof and tritium-compatible cryopump

Abstract

The invention relates to the field of fusion cold plates, in particular to a tritium-compatible cryopump cold plate, a preparation method thereof and a tritium-compatible cryopump. The invention provides a tritium compatible cryogenic pump cold plate which comprises a metal cold plate, wherein foam metal is welded on the surface of the metal cold plate; the adsorption material is arranged in the foam metal holes, and the adsorption material is obtained by curing a tritium compatible inorganic adsorption material, an inorganic adhesive and water according to the mass ratio of 1: (0.48-1.2): 1.5. Compared with a traditional cryopump cold plate, the specific surface area of the adsorption layer of the tritium-compatible cryopump cold plate is 1.47 times that of an activated carbon adsorption layer prepared through a spraying method, the thermal diffusion coefficient is increased by 6.8 times compared with that of the activated carbon adsorption layer prepared through the spraying method, the pumping speed of hydrogen is increased by 1.2 times, and the pumping speed of helium is increased by 12.7 times. The adsorption layer cannot be separated from the metal cold plate after long-time operation, and the requirement of fusion reactor construction for the high-performance tritium compatible low-temperature pump is met.

Description

Technical Field

[0001] This invention relates to the field of fusion cold plates, specifically a tritium-compatible cryogenic pump cold plate, its preparation method, and a tritium-compatible cryogenic pump. Background Technology

[0002] In tokamak fusion devices, tritium-compatible cryogenic adsorption pumps are the only feasible technology for helium ash removal. The cryogenic pump, supplied with cryogenic cooling by a refrigerator, causes gas to condense and adsorb on the surface of a cold plate, making it an indispensable component of the fusion reactor's vacuum system. To meet the stringent requirements of the fusion reactor's rapid adsorption-regeneration cycle, the cryogenic pump must possess high pumping speed characteristics, and the adsorption cold plate, as its core component, has a strong influence on the pumping speed, pumping capacity, and vacuum level of the cryogenic pump.

[0003] An adsorption cold plate consists of a metal cold plate and an adsorption layer on its surface. The bonding strength between the adsorption layer and the metal cold plate is the main factor affecting the continuous steady-state operation of the low-temperature cold plate. Therefore, the selection of adsorption materials, the forming technology of the adsorption layer, and the integration technology of the adsorption layer and the metal cold plate are the main research contents of low-temperature plates both domestically and internationally.

[0004] The integration between the adsorption layer and the metal cold plate has a significant impact on the low-temperature adsorption performance of the material. Currently, there are two main manufacturing processes for adsorption cold plates. One is to mix and cure the adsorption material particles with an adhesive, and then bond the formed block adsorption material to the surface of the metal cold plate using an adhesive to form the cold plate adsorption layer. The other is to mix the adsorption material particles with an adhesive to form a slurry, and then coat the adsorption material slurry onto the surface of the metal cold plate by spraying. After the slurry cures, it forms an adsorption layer and adheres to the surface of the cold plate metal.

[0005] However, existing inorganic binders suffer from low toughness and poor interfacial compatibility with adsorbent materials (such as activated carbon and molecular sieves), resulting in low bonding strength between the adsorbent layer and the cold plate metal surface. Adsorbent layers prepared using traditional methods exhibit poor thermal shock resistance and are prone to detachment during operation. More importantly, to ensure the adsorbent layer on the cold plate surface possesses sufficient mechanical strength and a high enough bond strength between the adsorbent layer and the cold plate metal surface, traditional adsorbent layer manufacturing methods necessitate adding large amounts of binder to the adsorbent material particles. However, the effective specific surface area of ​​the adsorbent layer decreases with increasing binder content, weakening the adsorption capacity of the adsorbent layer and reducing the pumping speed of the cold plate.

[0006] In addition, existing adsorbent materials and adhesives have fundamental limitations:

[0007] On the one hand, organic adsorbent materials (such as MOFs, COFs, etc.) and organic adhesives (such as epoxy resins, etc.) will continue to decompose under tritium β-ray irradiation, internal irradiation of dissolved tritium, and hydrogen isotope exchange reaction due to tritium β decay radiation, which cannot meet the stability requirements of tritium-compatible cryogenic pumps.

[0008] On the other hand, traditional inorganic adsorbent materials and adhesives are all low thermal conductivity materials, resulting in poor thermal conductivity of the adsorbent layer and the formation of thermal resistance barriers. This prevents the cold plate from efficiently transferring low temperatures to the interior of the adsorbent, creating a significant temperature gradient, weakening the hydrogen / helium adsorption capacity, and reducing the pumping speed of the cold plate in the cryogenic pump. Although more and more high-performance adsorbent materials have been developed, it is still impossible to completely retain excellent adsorption and thermal conductivity while simultaneously enhancing the adhesion strength between the adsorbent layer and the substrate. Summary of the Invention

[0009] In view of this, the technical problem to be solved by the present invention is to provide a tritium-compatible cryogenic pump cold plate and its preparation method, as well as a tritium-compatible cryogenic pump. The tritium-compatible cryogenic pump cold plate provided by the present invention retains the excellent adsorption performance of inorganic adsorbent materials, while the cold plate adsorption layer and the metal cold plate have high bonding strength. The cold plate adsorption layer has excellent thermal conductivity, specific surface area and hydrogen / helium pumping speed.

[0010] This invention provides a tritium-compatible cryogenic pump cooling plate, comprising:

[0011] Cold-rolled metal sheet with foamed metal welded to its surface;

[0012] The adsorbent material disposed within the pores of the foamed metal is obtained by curing a tritium-compatible inorganic adsorbent material, an inorganic binder, and water in a mass ratio of 1:(0.48~1.2):1.5.

[0013] The tritium-compatible cryogenic pump cold plate provided by this invention comprises a metal cold plate with foamed metal welded to its surface. Preferably, the metal cold plate with foamed metal welded to its surface is a metal cold plate with foamed metal vacuum brazed to its surface. Preferably, the foamed metal is selected from foamed copper, foamed aluminum, foamed silver, or foamed nickel; the metal cold plate is made of copper, aluminum, or stainless steel. This invention connects the foamed metal and the metal cold plate by vacuum brazing. Based on the inherent mechanical strength of the foamed metal, the amount of adhesive used in the adsorbent material can be significantly reduced. Simultaneously, the cold plate adsorption layer formed by the foamed metal and the adsorbent material within the foamed metal pores still maintains extremely high adhesion strength to the surface of the metal cold plate. Furthermore, the vacuum brazing connection between the cold plate adsorption layer and the metal cold plate allows the temperature of the near-cold plate to be directly conducted to the cold plate adsorption layer, resulting in a more uniform surface temperature of the cold plate adsorption layer. This effectively reduces the operating temperature of the adsorption layer, thereby significantly improving the pumping speed of the adsorption cold plate.

[0014] The adsorbent material of this invention is disposed within the pores of the foamed metal. The pore size of the foamed metal is 3 mm to 4 mm; the porosity of the foamed metal is 90% to 99%. Preferably, the thickness of the foamed metal is 5 mm to 8 mm. This invention utilizes the skeletal support of the foamed metal to significantly enhance its mechanical strength as an adsorbent layer on a cold plate and its bonding strength with the cold plate, solving the problem of easy detachment of the adsorbent layer on the cold plate. Furthermore, due to the extremely low apparent density and grid-like structural characteristics of the foamed metal, a network of heat conduction paths can be formed, significantly improving the thermal conductivity of the cold plate adsorbent layer.

[0015] The tritium-compatible cryogenic pump cooling plate provided by this invention further includes an adsorbent material disposed within the pores of the foamed metal. The adsorbent material is obtained by curing tritium-compatible inorganic adsorbent material, inorganic binder, and water in a mass ratio of 1:(0.48~1.2):1.5, wherein the tritium-compatible inorganic adsorbent material and the inorganic binder are based on their solid content. This invention reduces the amount of inorganic binder used, allowing the specific surface area of ​​the activated carbon raw material to be maintained to the maximum extent. The larger the specific surface area of ​​the adsorbent layer, the more effective adsorption sites it can provide, and the stronger its enrichment capacity for adsorbate molecules, thus improving the pumping speed of the adsorption cooling plate.

[0016] The tritium-compatible inorganic adsorbent material of this invention has a particle size of 100 µm to 450 µm. In some embodiments of this invention, the tritium-compatible inorganic adsorbent material comprises tritium-compatible inorganic adsorbent material with a particle size of 280 µm to 450 µm and tritium-compatible inorganic adsorbent material with a particle size of 100 µm to 154 µm, wherein the proportion of the tritium-compatible inorganic adsorbent material with a particle size of 280 µm to 450 µm is 55% to 65%, and the proportion of the tritium-compatible inorganic adsorbent material with a particle size of 100 µm to 154 µm is 35% to 45%.

[0017] The tritium-compatible inorganic adsorbent material described in this invention is preferably selected from coconut shell activated carbon. Coconut shell activated carbon has ultra-high specific surface area, large adsorption capacity, hydrophobicity, low impurity sensitivity, and low-temperature regeneration characteristics, making it suitable as an adsorbent material for extracting helium.

[0018] The inorganic adhesive described in this invention is selected from one or more of silicone-based adhesives or phosphate-based adhesives. Preferably, the inorganic adhesive described in this invention is a silicone-based adhesive, comprising silicon dioxide, alumina, zirconium dioxide, calcium carbonate, and sodium silicate. This invention uses an inorganic adhesive system to replace traditional organic binders. Inorganic adhesives have natural radiation resistance properties, avoiding the radioactivity and isotope exchange reactions of tritium, thus meeting the requirements of tritium-compatible cryogenic pumps.

[0019] This invention provides a method for preparing the tritium-compatible cryogenic pump cooling plate according to any of the above technical solutions, which includes the following steps:

[0020] Foamed metal is welded onto a metal cold plate to obtain a metal cold plate with foamed metal welded to its surface;

[0021] A suspension of tritium-compatible inorganic adsorbent material, inorganic binder, and water is filled into the foam metal pores of a metal cold plate with foam metal welded to its surface. After drying, it is cured and sintered to obtain a tritium-compatible cryogenic pump cold plate.

[0022] This invention first welds foamed metal onto a metal cold plate to obtain a metal cold plate with foamed metal welded to its surface. Preferably, foamed metal is first vacuum brazed onto a metal cold plate to obtain a metal cold plate with foamed metal welded to its surface. The metal cold plate and foamed metal described in this invention are the same as described above and will not be repeated.

[0023] This invention obtains a metal cold plate with foamed metal welded to its surface. Then, a suspension of tritium-compatible inorganic adsorbent material, inorganic binder, and water is filled into the pores of the foamed metal in the metal cold plate. After drying, it is cured and sintered to obtain a tritium-compatible cryogenic pump cold plate. Specifically, the tritium-compatible inorganic adsorbent material is crushed into particles, and then the tritium-compatible inorganic adsorbent material, inorganic binder, and water are mixed in a specific mass ratio and stirred to obtain a uniform suspension. The suspension is then filled into the pores of the foamed metal in the metal cold plate using a pouring method, dried, and cured and sintered to obtain the tritium-compatible cryogenic pump cold plate. The drying temperature is 70℃~90℃, and the drying time is not particularly limited, as long as the surface moisture of the material is removed. The curing and sintering temperature is 130℃~170℃, and the curing and sintering time is 3 h~8 h.

[0024] The preparation method provided by this invention involves obtaining a metal cold plate with foamed metal welded to its surface, and then filling the pores of the foamed metal with adsorbent material for curing. Since the foamed copper and the metal cold plate are connected by vacuum brazing, and then activated carbon is filled into the foamed copper, the curing of the adsorbent layer can be completed at a relatively low temperature, avoiding the problem of a significant decrease in the adsorption performance of activated carbon caused by directly brazing it at high temperatures.

[0025] The present invention also provides a tritium-compatible cryogenic pump, characterized in that it comprises: a baffle, a cold shield, a cold plate, a compressor, an expander, and a pump body; wherein the cold plate is the tritium-compatible cryogenic pump cold plate described in any of the above technical solutions.

[0026] This invention provides a tritium-compatible cryogenic pump cold plate, its preparation method, and a tritium-compatible cryogenic pump. The tritium-compatible cryogenic pump cold plate provided by this invention comprises: a metal cold plate with foamed metal welded to its surface; and an adsorbent material disposed within the pores of the foamed metal. The adsorbent material is obtained by curing tritium-compatible inorganic adsorbent material, inorganic binder, and water in a mass ratio of 1:(0.48~1.2):1.5. Compared to traditional cryogenic pump cold plates, this invention optimizes the structural design and preparation process of the tritium-compatible cryogenic pump cold plate, resulting in an adsorbent layer with a specific surface area 1.47 times that of an activated carbon adsorbent layer prepared by spraying, a thermal diffusivity 6.8 times higher than that of an activated carbon adsorbent layer prepared by spraying, and pumping speeds for hydrogen and helium increased by 1.2 and 12.7 times, respectively. During long-term operation, the adsorbent layer does not detach from the metal cold plate, meeting the requirements of fusion reactor construction for high-performance tritium-compatible cryogenic pumps. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the preparation process of copper plate-foamed copper according to the present invention;

[0028] Figure 2 This is a schematic diagram of the preparation process of the tritium-compatible cryogenic pump cooling plate described in this invention;

[0029] Figure 3 This is a photograph showing the fabrication process of the tritium-compatible cryogenic pump cooling plate according to an embodiment of the present invention.

[0030] Figure 4 This is a physical diagram illustrating the preparation process of the cryogenic pump cooling plate, which is a comparative example of the present invention. Detailed Implementation

[0031] This invention discloses a tritium-compatible cryogenic pump cooling plate, its preparation method, and the tritium-compatible cryogenic pump itself. Those skilled in the art can refer to the content of this document and appropriately modify the process parameters to achieve the desired result. It should be particularly noted that all similar substitutions and modifications are obvious to those skilled in the art and are considered to be included in this invention. The methods and applications of this invention have been described through preferred embodiments, and those skilled in the art can clearly modify or appropriately change and combine the methods and applications described herein without departing from the content, spirit, and scope of this invention to implement and apply the technology of this invention.

[0032] The present invention is in accordance with as follows Figure 2 The process shown is used to prepare a tritium-compatible cryogenic pump cooling plate, wherein the copper plate-foamed copper used is prepared according to the following... Figure 1 The process shown is used for preparation, wherein the copper plate is the metal cold plate described in this invention. Figure 1 This is a schematic diagram of the preparation process of copper plate-foamed copper according to the present invention. Figure 2 This is a schematic diagram of the preparation process of the tritium-compatible cryogenic pump cooling plate described in this invention.

[0033] The present invention will be further described below with reference to the embodiments:

[0034] Examples 1-6

[0035] First, copper foam (pore size 3 mm~4 mm, thickness 5 mm) and copper plate are vacuum brazed to obtain copper plate-copper foam. Coconut shell activated carbon is crushed into granules in a high-speed mill. Then, the coconut shell activated carbon granules, inorganic binder (Yikun Adhesive Industry, YK8927 single-component ultra-high temperature inorganic adhesive), and water are mixed at a mass ratio of 1:(0.48~1.2):1.5, where the coconut shell activated carbon granules and inorganic binder are based on solid content. The mixture is stirred with an electric stirrer to obtain a uniform suspension. The suspension is then filled into the pores of the copper plate-copper foam using a pouring method. Subsequently, it is dried in an 80℃ forced-air drying oven for 4 hours to remove surface moisture, and then cured and sintered in a 150℃ forced-air drying oven for 4 hours to finally obtain a tritium-compatible cryogenic pump cooling plate composed of copper plate-copper foam-activated carbon-binder.

[0036] The only difference between Examples 1-6 is the mass ratio of coconut shell activated carbon particles, inorganic binder, and water, as shown in Table 1:

[0037] Table 1

[0038]

[0039] like Figure 3 As shown, Figure 3 This is a schematic diagram of the preparation process of the tritium-compatible cryogenic pump cooling plate according to an embodiment of the present invention. It can be seen that the present invention first involves a copper plate (… Figure 3 Vacuum brazing of copper foam on the far left image yields copper plate-copper foam (e.g., ... Figure 3 (The middle image), and then a uniform suspension of coconut shell activated carbon particles, inorganic binder and water is poured into the foamed copper to obtain a tritium-compatible cryogenic pump cooling plate (such as...). Figure 3 (The rightmost image).

[0040] Comparative Examples 1-2

[0041] First, coconut shell activated carbon is crushed into granules in a high-speed grinder. Then, the coconut shell activated carbon granules, inorganic binder (Yikun Adhesive Industry, YK8927 single-component ultra-high temperature inorganic adhesive), and water are mixed in a fixed ratio and stirred with an electric mixer to obtain a uniform suspension. This suspension is then sprayed onto a copper plate. Subsequently, it is dried in an 80°C forced-air drying oven for 4 hours to remove moisture from the surface of the material. Finally, it is cured and sintered in a 150°C forced-air drying oven for 4 hours to obtain a low-temperature pump cooling plate composed of copper plate, activated carbon, and binder.

[0042] The only difference between Comparative Examples 1 and 2 is the mass ratio of coconut shell activated carbon particles, inorganic binder, and water, as shown in Table 2. The coconut shell activated carbon particles and inorganic binder are calculated based on their solid content as follows:

[0043] Table 2

[0044]

[0045] like Figure 4 As shown, Figure 4 This is a schematic diagram of the preparation process of the cryogenic pump cooling plate in Comparative Example 2 of the present invention. It can be seen that in Comparative Example 2 of the present invention, the copper plate (… Figure 4 A cryogenic pump cooling plate (such as the one shown on the left) is obtained by directly spraying a uniform suspension of coconut shell activated carbon particles, inorganic binder and water onto the plate. Figure 4 (The right side of the image).

[0046] Comparative Example 3

[0047] First, coconut shell activated carbon is crushed into granules in a high-speed mill. Then, the coconut shell activated carbon granules, inorganic binder (Yikun Adhesive Industry, YK8927 single-component ultra-high temperature inorganic adhesive), and water are mixed in a ratio of 1:0.8:1.5. The coconut shell activated carbon granules and inorganic binder are based on their solid content. Copper powder with the same mass fraction as the foamed copper in the example is added to the suspension instead of foamed copper. The suspension is stirred with an electric stirrer to obtain a uniform suspension, which is then sprayed onto a copper plate. Subsequently, it is dried in an 80°C forced-air drying oven for 4 hours to remove the moisture from the surface of the material, and then cured and sintered in a 150°C forced-air drying oven for 4 hours. Finally, a low-temperature pump cooling plate composed of copper plate, activated carbon, copper powder, and binder is obtained.

[0048] The specific surface area of ​​the adsorption layer of the tritium-compatible cryogenic pump cooling plate in Examples 1-5 was tested, and the results are shown in Table 3. Table 3 shows the specific surface area test results of the adsorption layer of the tritium-compatible cryogenic pump cooling plate in Examples 1-5 of the present invention.

[0049] Table 3

[0050]

[0051] The thermal diffusivity of the adsorption layer of the cryogenic pump cooling plate of Examples 1-5, Comparative Example 1 and Comparative Example 3 was tested, and the results are shown in Table 4. Table 4 shows the test results of the thermal diffusivity of the adsorption layer of the cryogenic pump cooling plate of Examples 1-5, Comparative Example 1 and Comparative Example 3 of the present invention.

[0052] Table 4

[0053]

[0054] As shown in Table 4, the tritium-compatible cryogenic pump cooling plate of the present invention has excellent thermal diffusion performance, and the thermally conductive channels of foamed copper with a three-dimensional network structure improve the heat transfer of the adsorbent far better than those of two-dimensional copper powder.

[0055] Pumping rate tests were conducted on the low-temperature adsorption of hydrogen and helium in Example 2 and Comparative Example 2. The coconut shell activated carbon used in both examples consisted of coconut shell activated carbon particles with a mixed particle size of 280 µm~450 µm and 100 µm~154 µm. The proportion of coconut shell activated carbon particles with a particle size of 280 µm~450 µm was 60%, and the proportion of particles with a particle size of 100 µm~154 µm was 40%. The results are shown in Table 5.

[0056] Table 5

[0057]

[0058] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A tritium-compatible cryogenic pump cooling plate, characterized in that, It includes: Cold-rolled metal sheet with foamed metal welded to its surface; The adsorbent material disposed within the pores of the foamed metal is obtained by curing a tritium-compatible inorganic adsorbent material, an inorganic binder, and water in a mass ratio of 1:(0.48~1.2):1.

5.

2. The tritium-compatible cryogenic pump cooling plate according to claim 1, characterized in that, The metal cold plate with foamed metal welded to its surface is specifically a metal cold plate with foamed metal vacuum brazed to its surface.

3. The tritium-compatible cryogenic pump cooling plate according to claim 1, characterized in that, The pore size of the foamed metal is 3 mm to 4 mm; The porosity of the foamed metal is 90%~99%.

4. The tritium-compatible cryogenic pump cooling plate according to claim 1, characterized in that, The thickness of the foamed metal is 5 mm to 8 mm.

5. The tritium-compatible cryogenic pump cooling plate according to claim 1, characterized in that, The tritium-compatible inorganic adsorbent material has a particle size of 100 µm to 450 µm.

6. The tritium-compatible cryogenic pump cooling plate according to claim 5, characterized in that, The tritium-compatible inorganic adsorbent material comprises tritium-compatible inorganic adsorbent material with a particle size of 280 µm to 450 µm and tritium-compatible inorganic adsorbent material with a particle size of 100 µm to 154 µm. The proportion of the tritium-compatible inorganic adsorbent material with a particle size of 280 µm to 450 µm is 55% to 65%, and the proportion of the tritium-compatible inorganic adsorbent material with a particle size of 100 µm to 154 µm is 35% to 45%.

7. The tritium-compatible cryogenic pump cooling plate according to claim 1, characterized in that, The material of the metal cold plate is copper, aluminum or stainless steel; The foam metal is selected from foam copper, foam aluminum, foam silver, or foam nickel; The tritium-compatible inorganic adsorbent material is selected from coconut shell activated carbon; The inorganic adhesive is selected from one or more of silicone-based adhesives or phosphate-based adhesives.

8. A method for preparing a tritium-compatible cryogenic pump cooling plate according to any one of claims 1 to 7, characterized in that, It includes the following steps: Foamed metal is welded onto a metal cold plate to obtain a metal cold plate with foamed metal welded to its surface; A suspension of tritium-compatible inorganic adsorbent material, inorganic binder, and water is filled into the foam metal pores of a metal cold plate with foam metal welded to its surface. After drying, it is cured and sintered to obtain a tritium-compatible cryogenic pump cold plate.

9. The preparation method according to claim 8, characterized in that, The curing and sintering temperature is 130℃~170℃, and the curing and sintering time is 3 h~8 h.

10. A tritium-compatible cryogenic pump, characterized in that, It includes: Baffles, cold shields, cold plates, compressors, expanders, and pump bodies; The cold plate is any one of the tritium-compatible cryogenic pump cold plates described in claims 1 to 7.

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