Cold screen structure for vacuum chamber of nuclear fusion device and hoisting method

Abstract

The application belongs to the technical field of nuclear fusion devices, and discloses a cold screen structure for a nuclear fusion device vacuum cavity and a hoisting method. In the cold screen structure, a first reinforcing ring plate, an upper cold screen and a middle cold screen are stacked from inside to outside and connected by first bolts; a second reinforcing ring plate, a lower cold screen and the middle cold screen are stacked from inside to outside and connected by second bolts; a third reinforcing ring plate is arranged on the inner side of the upper part of the upper cold screen, and the inner flange of the third reinforcing ring plate is fixed on the top inner surface of the upper cold screen by third bolts; low-temperature coil pipes are welded on the upper cold screen and the lower cold screen; the middle cold screen is surrounded by no less than four cold screen plates; the upper ends of multiple hoisting mechanisms are fixed with the vacuum cavity top plate, and the lower ends are connected with the upper cold screen and the inner flange on the inner flange in thermal insulation. The application is suitable for the current lead tank cold screen of a nuclear fusion device with large size, has high installation precision, high deformation control precision, small heat leakage, small stress and deformation after cold shrinkage, and is convenient for the maintenance of the internal components of the cold screen.

Description

Technical Field

[0001] This invention relates to the field of nuclear fusion device technology, and in particular to a cooling screen structure and hoisting method for a vacuum chamber in a nuclear fusion device. Background Technology

[0002] The current lead can is a key component of the feeder system, and the cold shield of the current lead can is an important part of it, playing a crucial role in providing a cryogenic safety barrier for the normal operation of the current leads and superconducting conductors within the current lead can. Due to the relatively large overall size of the current lead can cold shield (the dimensions of the current lead can cold shield are...), The current lead tank cold shield structure design and hoisting method for such multi-functional requirements (1.8×3m) are currently lacking. The installation accuracy requirements are high (installation accuracy is ±1mm), hoisting deformation control accuracy requirements are high (hoisting deformation control accuracy is ±1mm), thermal conductivity and heat conduction insulation requirements are high, and the stress and deformation requirements during cold shrinkage are low, the strength requirements are high, the heat leakage requirements are low, and the maintenance requirements are convenient.

[0003] Conventional cold shield structures and installation methods, using stainless steel or copper materials and secured with bolts or welding, suffer from high heat conduction, significant stress and deformation after cold contraction, and substantial heat leakage. They are also difficult to disassemble and maintain internal components. Furthermore, conventional cold shield structures and hoisting methods offer limited functionality and low installation precision. When dealing with current lead tank cold shields and hoisting methods that require large dimensions, high installation precision, precise deformation control, minimal heat leakage, low stress and deformation after cold contraction, and convenient maintenance, conventional structures and methods cannot meet the precision and deformation control requirements, and fail to address issues related to heat leakage, thermal conductivity, cold contraction, and internal maintenance. A new design approach and installation method are urgently needed to solve the problems associated with the structure and hoisting of current lead tank cold shields. Summary of the Invention

[0004] This invention aims to at least partially solve one of the technical problems in related technologies. Therefore, one objective of this invention is to provide a cold shield structure for the vacuum chamber of a nuclear fusion device, suitable for the cold shield of the current lead canister in a large-sized nuclear fusion device, featuring high installation accuracy, high deformation control accuracy, low heat leakage, low stress and deformation after cold shrinkage, and convenient maintenance of internal components.

[0005] A cooling screen structure for a vacuum chamber in a nuclear fusion device according to an embodiment of the present invention includes:

[0006] A cold shield, specifically a current lead can cold shield, comprises an upper cold shield, a middle cold shield, a lower cold shield, a first reinforcing ring plate, a second reinforcing ring plate, and a third reinforcing ring plate. The first reinforcing ring plate, the lower part of the upper cold shield, and the upper part of the middle cold shield are stacked from the inside out and connected by a first bolt. The second reinforcing ring plate, the upper part of the lower cold shield, and the lower part of the middle cold shield are stacked from the inside out and connected by a second bolt. The upper end of the third reinforcing ring plate has an inward flange. The third reinforcing ring plate is stacked on the upper inner side of the upper cold shield, and the inward flange is fixed to the top inner surface of the upper cold shield by a third bolt. Low-temperature coils are welded onto the upper and lower cold shields respectively. The middle cold shield is formed by at least four cold shield plates.

[0007] The hoisting mechanism comprises multiple hoisting mechanisms, which are evenly distributed circumferentially between the upper cooling screen and the top plate of the vacuum cavity located above the upper cooling screen. The upper ends of the multiple hoisting mechanisms are respectively fixed to the top plate of the vacuum cavity, and the lower ends of the multiple hoisting mechanisms are thermally connected to the upper cooling screen and the inner flange on the inner flange.

[0008] The cold shield structure for the vacuum chamber of a nuclear fusion device according to the first aspect of the present invention is suitable for the cold shield of the current lead canister of a large-sized nuclear fusion device. It has a simple structure, high installation accuracy, high deformation control accuracy, low heat leakage, low stress and deformation after cold shrinkage, and convenient maintenance of the internal components of the cold shield.

[0009] In some embodiments, the upper cooling screen, the middle cooling screen, and the lower cooling screen are made of oxygen-free copper.

[0010] In some embodiments, the first reinforcing ring plate, the second reinforcing ring plate, and the third reinforcing ring plate are made of stainless steel.

[0011] In some embodiments, the cooling screen is composed of six identical cooling screen panels.

[0012] In some embodiments, when maintaining the internal components of the cold screen, two to three cold screen panels are symmetrically removed.

[0013] In some embodiments, each of the hoisting mechanisms includes a hoisting rod, an insulation board, and a base; the upper end of the hoisting rod is fixed to the top plate of the vacuum chamber, and the lower end of the hoisting rod passes sequentially through the top of the upper cooling screen, the inner flange, the insulation board, and the base arranged in layers above and below; a gap is left between the circumference of the hoisting rod and the top of the upper cooling screen, the inner flange, and the insulation board; and the lower end of the hoisting rod is fixed to the base by a fourth bolt.

[0014] In some embodiments, grooves are formed on both the upper and lower surfaces of the insulation board.

[0015] In some embodiments, the insulation board is an epoxy board.

[0016] In some embodiments, the suspension rod includes a connecting plate, a fixing rod, and a connecting rod; the connecting plate is fixed to the top plate of the vacuum chamber, the upper end of the fixing rod is fixed to the connecting plate, the lower end of the fixing rod is fixed to the upper end of the connecting rod by a fifth bolt, the lower end of the connecting rod passes through the top of the upper cooling screen, the inner flange, the heat insulation board, and the base arranged in layers, a gap is left between the circumference of the connecting rod and the top of the upper cooling screen, the inner flange, and the heat insulation board, and the lower end of the connecting rod is fixed to the base by the fourth bolt.

[0017] In some embodiments, the fixing rod includes a first stainless steel tube and a first connecting block welded to the lower end of the first stainless steel tube; the upper end of the first stainless steel tube is welded and fixed to the connecting plate, and the first connecting block is fixed to the connecting rod by the fifth bolt.

[0018] In some embodiments, the connecting rod includes a second stainless steel tube and second connecting blocks welded to the upper and lower ends of the second stainless steel tube respectively; the second connecting block at the upper end of the second stainless steel tube is fixed to the first connecting block by the fifth bolt; the second connecting block at the lower end of the second stainless steel tube passes through the top of the upper cooling screen, the inner flange, the heat insulation plate and the base arranged in layers, and a gap is left between the circumferential surface of the second connecting block at the lower end of the second stainless steel tube and the top of the upper cooling screen, the inner flange and the heat insulation plate, and the second connecting block at the lower end of the second stainless steel tube is fixed to the base by the fourth bolt.

[0019] In some embodiments, the second connecting block has a protrusion, the first connecting block has a first clamping portion, and the base has a second clamping portion; the protrusion of the second connecting block at the upper end of the second stainless steel tube is clamped in the first clamping portion and fixed by the fifth bolt; the protrusion of the second connecting block at the lower end of the second stainless steel tube is clamped in the second clamping portion and fixed by the fourth bolt.

[0020] A second aspect of the present invention also provides a method for hoisting a cooling screen structure inside a vacuum chamber of a nuclear fusion device. This cooling screen structure is the same as the one described in the first aspect of the present invention. The hoisting method includes the following steps:

[0021] The upper ends of the multiple hoisting mechanisms are fixed to the top plate of the vacuum chamber, the third reinforcing ring plate is connected to the upper cooling screen using the third bolt, the upper cooling screen is hoisted onto the lower end of the hoisting mechanism, and the lower ends of the multiple hoisting mechanisms are thermally connected to the upper cooling screen and the inner flange on the inner flange.

[0022] The lower cooling screen is temporarily fixed and its designed position is adjusted using an adjustable support fixture.

[0023] The cold screen panel of the middle cold screen is sequentially connected and installed to the upper cold screen and the lower cold screen.

[0024] The hoisting method for the cooling screen structure inside the vacuum chamber of a nuclear fusion device according to the second aspect of the present invention is easy to operate, and the installed cooling screen structure inside the vacuum chamber of a nuclear fusion device has basically the same technical effect as the cooling screen structure inside the vacuum chamber of a nuclear fusion device according to the first aspect of the present invention, and will not be described again here.

[0025] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0026] Figure 1 This is a schematic diagram illustrating the application of the cooling screen structure in the vacuum cavity of a nuclear fusion device according to an embodiment of the present invention.

[0027] Figure 2 yes Figure 1 A schematic diagram of a longitudinal section;

[0028] Figure 3 This is a longitudinal cross-sectional schematic diagram of a cooling screen structure for a vacuum chamber in a nuclear fusion device according to an embodiment of the present invention.

[0029] Figure 4 yes Figure 2 Enlarged diagram of point A in the diagram;

[0030] Figure 5 yes Figure 2 Enlarged diagram of point B in the diagram;

[0031] Figure 6 yes Figure 3 Enlarged diagram of point C in the diagram;

[0032] Figure 7 This is a three-dimensional schematic diagram of the connection between the hoisting mechanism and the third reinforcing ring plate in the vacuum chamber internal cooling screen structure of a nuclear fusion device according to an embodiment of the present invention.

[0033] Figure 8This is a side view of the connection between the hoisting mechanism and the third reinforcing ring plate in the vacuum chamber internal cooling screen structure of a nuclear fusion device according to an embodiment of the present invention.

[0034] Figure 9 This is a longitudinal cross-sectional view of the connection between the hoisting mechanism and the third reinforcing ring plate in the vacuum chamber internal cooling screen structure of a nuclear fusion device, according to an embodiment of the present invention.

[0035] Figure Labels

[0036] Cooling screen structure 1000 for vacuum chamber of nuclear fusion device; cooling screen 1; upper cooling screen 101; middle cooling screen 102; cooling screen plate 1021; lower cooling screen 103; first reinforcing ring plate 104; second reinforcing ring plate 105; third reinforcing ring plate 106; inner flange 1061; bolt connection hole 10611; first bolt 107; second bolt 108; third bolt 109; hoisting mechanism 2; hoisting rod 201; connecting plate 2011; fixing rod 2012; first stainless steel pipe 20121; first connecting block 20122; first clamping part 201221; connecting rod 2013; second stainless steel pipe 20131; second connecting block 20132; protrusion 201321; fifth bolt 2014; heat insulation plate 202; groove 2021; base 203; second clamping part 2031; fourth bolt 204; vacuum chamber top plate 3. Detailed Implementation

[0037] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0038] The following is combined with Figures 1 to 9 This invention describes an embodiment of a cooling screen structure 1000 for a vacuum chamber in a nuclear fusion device and its hoisting method.

[0039] like Figures 1 to 9 As shown, a cold screen structure 1000 for a vacuum chamber of a nuclear fusion device according to a first aspect embodiment of the present invention includes a cold screen 1 and a hoisting mechanism 2.

[0040] Cold shield 1 is a cold shield for the current lead can, playing a crucial role in providing a low-temperature safety barrier for the normal operation of the current leads and superconducting conductors inside the current lead can. Cold shield 1 includes an upper cold shield 101, a middle cold shield 102, a lower cold shield 103, a first reinforcing ring plate 104, a second reinforcing ring plate 105, and a third reinforcing ring plate 106. Among these, the upper cold shield 101, the middle cold shield 102, and the lower cold shield 103 have good thermal conductivity.

[0041] The first reinforcing ring plate 104, the lower part of the upper cold screen 101, and the upper part of the middle cold screen 102 are stacked from the inside out and connected by the first bolt 107. The first bolt 107 is evenly distributed circumferentially, thus achieving a reliable connection between the upper cold screen 101 and the middle cold screen 102. Furthermore, the first reinforcing ring plate 104 effectively strengthens the structural strength of the cold screen 1, ensuring that deformation control and installation accuracy control of the cold screen 1 after assembly meet the requirements. The second reinforcing ring plate 105, the upper part of the lower cold screen 103, and the lower part of the middle cold screen 102 are stacked from the inside out and connected by the second bolt 108. The second bolt 108 is evenly distributed circumferentially, achieving a reliable connection between the lower cold screen 103 and the middle cold screen 102. Furthermore, the second reinforcing ring plate 105 effectively strengthens the structural strength of the cold screen 1, ensuring that deformation control and installation accuracy control of the cold screen 1 after assembly meet the requirements. The upper end of the third reinforcing ring plate 106 has an inward flange 1061. The design of this inward flange 1061 effectively controls the deformation of the upper cold screen 101 and ensures the overall installation position accuracy of the cold screen 1. The third reinforcing ring plates 106 are stacked on the upper inner side of the upper cold screen 101, and the inward flange 1061 is fixed to the top inner surface of the upper cold screen 101 by the third bolts 109. The third bolts 109 are evenly distributed circumferentially (see reference). Figure 7The evenly spaced bolt holes 10611 on the inner flange 1061 ensure a reliable connection between the third reinforcing ring plate 106 and the upper cold screen 101. By setting the third reinforcing ring plate 106, the strength of the upper cold screen 101 is enhanced during suspension, reducing deformation and helping to ensure that deformation control and installation accuracy of the cold screen 1 meet requirements after assembly. Therefore, by setting the first reinforcing ring plate 104, the second reinforcing ring plate 105, and the third reinforcing ring plate 106, the overall structural strength of the cold screen 1 can be better strengthened, ensuring that the hoisting deformation control and installation accuracy control of the cold screen 1 meet requirements after assembly, controlling the hoisting deformation accuracy within ±1mm and the installation accuracy within ±1mm. Low-temperature coils (not shown in the figure) are welded onto the upper cooling screen 101 and the lower cooling screen 103 respectively. That is, the low-temperature coils are only set on the upper cooling screen 101 and the lower cooling screen 103, while they are not set on the intermediate cooling screen 102. In this way, the low-temperature heat from the low-temperature coils can be directly conducted to the upper cooling screen 101 and the lower cooling screen 103, and then quickly conducted to the intermediate cooling screen 102 through the upper cooling screen 101 and the lower cooling screen 103. This keeps the entire cooling screen 1 at a low temperature, ensuring that the cooling screen 1 meets the design temperature requirements and ensures the normal operation of the current leads and superconducting conductors in the current lead tank. The intermediate cooling screen 102 is composed of no less than four cooling screen plates 1021. This means that the upper and lower parts of each cooling screen plate 1021 are located on the outside of the upper cooling screen 101 and the lower cooling screen 103, respectively. The upper part of each cooling screen plate 1021 is fixed to the lower part of the upper cooling screen 101 and the first reinforcing ring plate 104 by the first bolt 107, and the lower part of each cooling screen plate 1021 is fixed to the upper part of the lower cooling screen 103 and the second reinforcing ring plate 105 by the second bolt 108. In this way, the installation and disassembly of each cooling screen plate 1021 is convenient and easy to operate. In particular, by symmetrically removing some cooling screen plates 1021, such as symmetrically removing 2-3 cooling screen plates 1021, the internal pipes, valves and other internal components of the cooling screen 1 can be maintained. This facilitates subsequent maintenance and ensures that the position, deformation and welded cooling pipes of the cooling screen 1 are not affected by the maintenance operation.

[0042] There are multiple hoisting mechanisms 2, which are evenly distributed circumferentially between the upper cooling screen 101 and the top plate 3 of the vacuum cavity located above the upper cooling screen 101. For example, Figure 7 and Figure 8The diagram illustrates three hoisting mechanisms 2, spaced 120° apart. The upper ends of each hoisting mechanism 2 are fixed to the top plate 3 of the vacuum chamber, while the lower ends are thermally connected to the upper cold screen 101 and the inner flange 1061. By suspending the cold screen 1 using the evenly spaced hoisting mechanisms 2, the oversized cold screen 1 can be suspended and fixed, effectively reducing the stress and deformation caused by cold contraction, thus ensuring the installation accuracy of the cold screen 1. Simultaneously, the point connection between the hoisting mechanisms 2 and the cold screen 1 minimizes the contact area, effectively reducing heat transfer. Furthermore, because the lower ends of the hoisting mechanisms 2 are thermally insulated from the upper cold screen 101 and the third reinforcing ring plate 106, the low-temperature heat from the upper cold screen 101 and the third reinforcing ring plate 106 is effectively prevented from being transferred to the hoisting mechanisms 2, thereby effectively reducing heat leakage from the cold screen 1.

[0043] In summary, the cold screen structure 1000 for the vacuum chamber of a nuclear fusion device according to the first aspect of the present invention is suitable for the cold screen of the current lead canister of a large-sized nuclear fusion device. It has a simple structure, high installation accuracy, high deformation control accuracy, low heat leakage, low stress and deformation after cold shrinkage, and convenient maintenance of the internal components of the cold screen 1.

[0044] In some embodiments, the upper cooling screen 101, the middle cooling screen 102, and the lower cooling screen 103 are made of oxygen-free copper. Since no low-temperature coil is installed on the middle cooling screen 102, the upper cooling screen 101, the middle cooling screen 102, and the lower cooling screen 103 are made of oxygen-free copper, which has better thermal conductivity than stainless steel. Therefore, when the low-temperature coil is started, the upper cooling screen 101 and the lower cooling screen 103 can quickly transfer low-temperature heat to the middle cooling screen 102.

[0045] In some embodiments, the first reinforcing ring plate 104, the second reinforcing ring plate 105, and the third reinforcing ring plate 106 are made of stainless steel. Stainless steel has good strength and can effectively enhance the structural strength of the cold screen 1.

[0046] In some embodiments, the intermediate cooling screen 102 is composed of six identical cooling screen panels 1021. Due to the large size of the cooling screen 1, the intermediate cooling screen 102 is correspondingly large and heavy. The intermediate cooling screen 102 is constructed from six cooling screen panels 1021. This design ensures that each panel has a moderate weight, allowing for easy manual movement and convenient installation and disassembly. Furthermore, when maintaining the internal components of the cooling screen 1, two to three panels 1021 can be symmetrically removed. This allows for maintenance of the internal pipes, valves, and other components, facilitating subsequent maintenance while ensuring the structural strength of the cooled screen 1 after removal, preventing deformation and ensuring that the position, deformation, and welded cooling pipes of the cooling screen 1 are unaffected by maintenance operations.

[0047] In some embodiments, when maintaining the internal components of the cold screen 1, two to three cold screen plates 1021 are symmetrically removed. This allows for maintenance of the internal components of the cold screen 1, such as internal pipes and valves, facilitating subsequent maintenance while ensuring the structural strength of the cold screen 1 after removal, preventing deformation of the intermediate cold screen 102, and ensuring that the position, deformation, and welded cooling pipes of the cold screen 1 are not affected by the maintenance operation.

[0048] In some embodiments, such as Figures 6 to 9 As shown, each hoisting mechanism 2 includes a hoisting rod 201, an insulation plate 202, and a base 203; the upper end of the hoisting rod 201 is fixed to the top plate 3 of the vacuum chamber, and the lower end of the hoisting rod 201 passes through the top of the upper cooling screen 101, the inner flange 1061, the insulation plate 202, and the base 203 arranged in layers. There is a gap between the circumference of the hoisting rod 201 and the top of the upper cooling screen 101, the inner flange 1061, and the insulation plate 202. The lower end of the hoisting rod 201 is fixed to the base 203 by a fourth bolt 204. Because there are gaps between the circumference of the hanger 201 and the top of the upper cooling screen 101, the inner flange 1061, and the insulation plate 202, the hanger 201 does not directly contact the upper cooling screen 101, the inner flange 1061, and the insulation plate 202, but only contacts the base 203 and the fourth bolt 204. However, the base 203 is insulated from the inner flange 1061 by the insulation plate 202. Therefore, the insulation plate 202 effectively reduces the transfer of low-temperature heat from the upper cooling screen 101 and the inner flange 1061 to the base 203, the fourth bolt 204, and the hanger 201.

[0049] In some embodiments, such as Figure 9 As shown, both the upper and lower surfaces of the insulation board 202 have grooves 2021. It can be understood that the insulation board 202 is placed between the base 203 and the inner flange 1061 of the third reinforcing ring plate 106. The grooves 2021 on both the upper and lower surfaces of the insulation board 202 reduce heat conduction, decrease the contact area, and reduce heat leakage. Based on on-site measurement data, the strength of the epoxy board is adjusted to ensure that the overall cold shield 1 meets the positional requirements.

[0050] In some embodiments, the insulation board 202 is an epoxy board. It is understood that the epoxy board is placed between the base 203 and the inner flange 1061 of the third reinforcing ring plate 106. The epoxy board has low thermal conductivity and good structural strength, which can effectively reduce heat conduction and reduce heat leakage. The strength of the epoxy board is adjusted according to the on-site measurement data to ensure that the overall cold screen 1 meets the position requirements.

[0051] It should be noted that insulation board 202 can also be made of other materials with good strength and low thermal conductivity.

[0052] In some embodiments, the boom 201 includes a connecting plate 2011, a fixing rod 2012, and a connecting rod 2013. The connecting plate 2011 is fixed to the top plate 3 of the vacuum chamber. Specifically, the connecting plate 2011 is positioned and welded on the top plate 3 of the vacuum chamber using a laser tracker, resulting in high installation accuracy and good connection strength. The upper end of the fixing rod 2012 is fixed to the connecting plate 2011. Specifically, the fixing rod 2012 is inserted into the recess of the connecting plate 2011 for welding, facilitating the positioning and welding of the fixing rod 2012 and ensuring the positional requirements of the fixing rod 2012. The lower end of the fixing rod 2012 is fixed to the upper end of the connecting rod 2013 using a fifth bolt 2014, which facilitates the installation and disassembly of the connecting rod 2013 and the fixing rod 2012. The lower end of the connecting rod 2013 passes through the top, inner flange 1061, insulation plate 202, and base 203 of the upper and lower stacked cooling screen 101. A gap is left between the circumference of the connecting rod 2013 and the top, inner flange 1061, and insulation plate 202 of the upper cooling screen 101. The lower end of the connecting rod 2013 is fixed to the base 203 by a fourth bolt 204. Because the circumference of the connecting rod 2013 is close to the top, inner flange 1061, and insulation plate 202 of the upper cooling screen 101... There are gaps between the insulation panels 202. The connecting rod 2013 does not directly contact the upper cold screen 101, the inner flange 1061 and the insulation panel 202, but only contacts the base 203 and the fourth bolt 204. However, the base 203 is insulated from the inner flange 1061 by the insulation panel 202. Therefore, the insulation panel 202 effectively reduces the transfer of low-temperature heat from the upper cold screen 101 and the inner flange 1061 to the base 203, the fourth bolt 204 and the connecting rod 2013.

[0053] In some embodiments, the fixing rod 2012 includes a first stainless steel tube 20121 and a first connecting block 20122 welded to the lower end of the first stainless steel tube 20121. The first stainless steel tube 20121 has good strength, ensuring the strength of the suspended cold screen 1. Simultaneously, the first stainless steel tube 20121 reduces heat leakage by decreasing its cross-sectional area. The upper end of the first stainless steel tube 20121 is welded and fixed to the connecting plate 2011. Specifically, the first stainless steel tube 20121 is inserted into the recess of the connecting plate 2011 for welding, facilitating the positioning and welding of the fixing rod 2012 and ensuring the positional requirements of the fixing rod 2012. The first connecting block 20122 is fixed to the connecting rod 2013 using a fifth bolt 2014, facilitating installation and disassembly.

[0054] In some embodiments, the connecting rod 2013 includes a second stainless steel tube 20131 and second connecting blocks 20132 correspondingly welded to the upper and lower ends of the second stainless steel tube 20131. The second stainless steel tube 20131 has good strength, ensuring the strength of the suspended cold screen 1. At the same time, the second stainless steel tube 20131 reduces heat leakage by reducing its cross-sectional area. The second connecting block 20132 at the upper end of the second stainless steel tube 20131 is fixed to the first connecting block 20122 with a fifth bolt 2014, which facilitates installation and disassembly. The second connecting block 20132 at the lower end of the second stainless steel tube 20131 passes through the top, inner flange 1061, insulation plate 202 and base 203 of the upper cold screen 101 arranged in layers. There is a gap between the circumference of the second connecting block 20132 at the lower end of the second stainless steel tube 20131 and the top, inner flange 1061 and insulation plate 202 of the upper cold screen 101. The second connecting block 20132 at the lower end of the second stainless steel tube 20131 is fixed to the base 203 by the fourth bolt 204. Because there is a gap between the circumference of the second connecting block 20132 at the lower end of the second stainless steel pipe 20131 and the top of the upper cold screen 101, the inner flange 1061, and the insulation plate 202, the second connecting block 20132 at the lower end of the second stainless steel pipe 20131 does not directly contact the upper cold screen 101, the inner flange 1061, and the insulation plate 202, but only contacts the base 203 and the fourth bolt 204. However, the base 203 is insulated from the inner flange 1061 by the insulation plate 202. Therefore, the insulation plate 202 effectively reduces the transfer of low-temperature heat from the upper cold screen 101 and the inner flange 1061 to the base 203, the fourth bolt 204, and the connecting rod 2013.

[0055] In some embodiments, the second connecting block 20132 has a protrusion 201321, the first connecting block 20122 has a first clamping portion 201221, and the base 203 has a second clamping portion 2031. The protrusion 201321 of the second connecting block 20132 at the upper end of the second stainless steel tube 20131 is clamped in the first clamping portion 201221 and fixed by a fifth bolt 2014; the protrusion 201321 of the second connecting block 20132 at the lower end of the second stainless steel tube 20131 is clamped in the second clamping portion 2031 and fixed by a fourth bolt 204. Thus, the connection is reliable, and installation and disassembly are convenient.

[0056] A second aspect of the present invention provides a method for hoisting a cooling screen structure 1000 for use in a vacuum chamber of a nuclear fusion device. This cooling screen structure 1000 is the same as the cooling screen structure 1000 for use in a vacuum chamber of a nuclear fusion device according to the first aspect of the present invention. The hoisting method includes the following steps:

[0057] The upper ends of multiple lifting mechanisms 2 are fixed to the top plate 3 of the vacuum chamber. The third reinforcing ring plate 106 is connected to the upper cooling screen 101 with the third bolt 109. The upper cooling screen 101 is hoisted onto the lower end of the lifting mechanism 2. The lower ends of multiple lifting mechanisms 2 are insulatedly connected to the upper cooling screen 101 and the inner flange 1061 on the inner flange 1061. Specifically, the connecting plate 2011 of multiple lifting mechanisms 2 is positioned and welded on the top plate 3 of the vacuum chamber using a laser tracker. The fixing rod 2012 of the lifting mechanism 2 is inserted into the sink of the connecting plate 2011 and welded and fixed. The third reinforcing ring plate 106 is connected to the upper cooling screen 101 with the third bolt 109. The base 203, the insulation plate 202 and the connecting rod 2013 are connected with the fourth bolt 204, and the connecting rod 2013 passes through the inner flange 1061 and the upper cooling screen 101 and is connected to the fixing rod 2012.

[0058] The lower cooling screen 103 is temporarily fixed and its designed position is adjusted using an adjustable support fixture.

[0059] The cooling screen plate 1021 of the intermediate cooling screen 102 is connected and installed sequentially with the upper cooling screen 101 and the lower cooling screen 103.

[0060] The hoisting method of the cooling screen structure 1000 for the vacuum chamber of a nuclear fusion device according to the second aspect embodiment of the present invention is easy to operate. The installed cooling screen structure 1000 for the vacuum chamber of a nuclear fusion device has basically the same technical effect as the cooling screen structure 1000 for the vacuum chamber of a nuclear fusion device according to the first aspect embodiment, and will not be described again here.

[0061] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A cooling screen structure for use in the vacuum chamber of a nuclear fusion device, characterized in that, include: A cold shield, specifically a current lead can cold shield, comprises an upper cold shield, a middle cold shield, a lower cold shield, a first reinforcing ring plate, a second reinforcing ring plate, and a third reinforcing ring plate. The first reinforcing ring plate, the lower part of the upper cold shield, and the upper part of the middle cold shield are stacked from the inside out and connected by a first bolt. The second reinforcing ring plate, the upper part of the lower cold shield, and the lower part of the middle cold shield are stacked from the inside out and connected by a second bolt. The upper end of the third reinforcing ring plate has an inward flange. The third reinforcing ring plate is stacked on the upper inner side of the upper cold shield, and the inward flange is fixed to the top inner surface of the upper cold shield by a third bolt. Low-temperature coils are welded onto the upper and lower cold shields respectively. The middle cold shield is formed by at least four cold shield plates. The hoisting mechanism comprises multiple hoisting mechanisms, which are evenly distributed circumferentially between the upper cooling screen and the top plate of the vacuum cavity located above the upper cooling screen. The upper ends of the multiple hoisting mechanisms are respectively fixed to the top plate of the vacuum cavity, and the lower ends of the multiple hoisting mechanisms are thermally connected to the upper cooling screen and the inner flange on the inner flange.

2. The cooling screen structure for the vacuum cavity of a nuclear fusion device according to claim 1, characterized in that, The upper cooling screen, the middle cooling screen, and the lower cooling screen are made of oxygen-free copper.

3. The cooling screen structure for the vacuum cavity of a nuclear fusion device according to claim 1, characterized in that, The first reinforcing ring plate, the second reinforcing ring plate, and the third reinforcing ring plate are made of stainless steel.

4. The cooling screen structure for the vacuum cavity of a nuclear fusion device according to claim 1, characterized in that, The intermediate cooling screen is composed of 6 identical cooling screen panels.

5. The cooling screen structure for the vacuum cavity of a nuclear fusion device according to claim 1, characterized in that, When maintaining the internal components of the cold screen, two to three cold screen panels are symmetrically removed.

6. The cooling screen structure for the vacuum cavity of a nuclear fusion device according to claim 1, characterized in that, Each of the hoisting mechanisms includes a hoisting rod, an insulation board, and a base; the upper end of the hoisting rod is fixed to the top plate of the vacuum chamber, and the lower end of the hoisting rod passes sequentially through the top of the upper cooling screen, the inner flange, the insulation board, and the base arranged in layers above and below. A gap is left between the circumference of the hoisting rod and the top of the upper cooling screen, the inner flange, and the insulation board, and the lower end of the hoisting rod is fixed to the base by a fourth bolt.

7. The cooling screen structure for the vacuum cavity of a nuclear fusion device according to claim 6, characterized in that, The insulation board has grooves on both its upper and lower surfaces.

8. The cooling screen structure for the vacuum cavity of a nuclear fusion device according to claim 6, characterized in that, The insulation board is an epoxy board.

9. The cooling screen structure for the vacuum cavity of a nuclear fusion device according to claim 6, characterized in that, The suspension rod includes a connecting plate, a fixing rod, and a connecting rod; the connecting plate is fixed to the top plate of the vacuum chamber, the upper end of the fixing rod is fixed to the connecting plate, the lower end of the fixing rod is fixed to the upper end of the connecting rod by a fifth bolt, the lower end of the connecting rod passes through the top of the upper cooling screen, the inner flange, the heat insulation board, and the base arranged in layers, a gap is left between the circumference of the connecting rod and the top of the upper cooling screen, the inner flange, and the heat insulation board, and the lower end of the connecting rod is fixed to the base by a fourth bolt.

10. The cooling screen structure for the vacuum cavity of a nuclear fusion device according to claim 9, characterized in that, The fixing rod includes a first stainless steel tube and a first connecting block welded to the lower end of the first stainless steel tube; the upper end of the first stainless steel tube is welded and fixed to the connecting plate, and the first connecting block is fixed to the connecting rod by the fifth bolt.

11. The cooling screen structure for a vacuum cavity in a nuclear fusion device according to claim 10, characterized in that, The connecting rod includes a second stainless steel tube and second connecting blocks welded to the upper and lower ends of the second stainless steel tube respectively; the second connecting block at the upper end of the second stainless steel tube is fixed to the first connecting block by the fifth bolt; the second connecting block at the lower end of the second stainless steel tube passes through the top of the upper cooling screen, the inner flange, the heat insulation plate and the base arranged in layers, and a gap is left between the circumference of the second connecting block at the lower end of the second stainless steel tube and the top of the upper cooling screen, the inner flange and the heat insulation plate; the second connecting block at the lower end of the second stainless steel tube is fixed to the base by the fourth bolt.

12. The cooling screen structure for a vacuum cavity in a nuclear fusion device according to claim 11, characterized in that, The second connecting block has a protrusion, the first connecting block has a first clamping part, and the base has a second clamping part; the protrusion of the second connecting block at the upper end of the second stainless steel tube is clamped in the first clamping part and fixed by the fifth bolt; the protrusion of the second connecting block at the lower end of the second stainless steel tube is clamped in the second clamping part and fixed by the fourth bolt.

13. A method for hoisting a cooling screen structure inside a vacuum chamber of a nuclear fusion device as described in any one of claims 1 to 12, characterized in that, Includes the following steps: The upper ends of the multiple hoisting mechanisms are fixed to the top plate of the vacuum chamber, the third reinforcing ring plate is connected to the upper cooling screen using the third bolt, the upper cooling screen is hoisted onto the lower end of the hoisting mechanism, and the lower ends of the multiple hoisting mechanisms are thermally connected to the upper cooling screen and the inner flange on the inner flange. The lower cooling screen is temporarily fixed and its designed position is adjusted using an adjustable support fixture. The cold screen panel of the middle cold screen is sequentially connected and installed to the upper cold screen and the lower cold screen.

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