Divertor structure of Tokamak device and design optimization method thereof

Abstract

The invention discloses a divertor structure of a Tokamak device and a design optimization method of the divertor structure, and relates to the technical field of magnetic confinement nuclear fusion. Based on a compact fusion reactor, the design of the physical structure of the divertor is carried out, and the physical structure of the divertor is optimized in combination with numerical simulation and evaluation technologies; according to the optimal divertor structure, the thermal load can be effectively controlled, and meanwhile the defects, limitation and the like caused by a configuration optimization technology and an external impurity injection technology are overcome; besides, in the design optimization process, the impurity injection effect, the impurity removal effect and the like are further considered, and therefore the optimal divertor structure further has the good impurity removal level and impurity shielding capacity.

Description

Technical Field

[0001] The present application relates to the technical field of magnetic confinement nuclear fusion, and in particular to a divertor structure of a tokamak device and a design optimization method thereof. Background Art

[0002] In a tokamak device, the divertor is a key component of the tokamak device, which can introduce the interaction between plasma and the material surface to an area far away from the core. The particle flow and energy flow from the core to the edge area need to be transported radially across the outermost closed magnetic field lines, flow into the open magnetic field line area, and then transported to the divertor operating space in the lower cavity.

[0003] Therefore, the main function of the divertor is to achieve effective particle flow and heat flow control. At present, for the tokamak device in the field of magnetic confinement fusion with a divertor component, the heat load on the divertor target plate has always been one of the difficult problems to overcome, especially for the reactor-level fusion device. The reactor-level fusion device involved here refers to a very high fusion power (i.e., the heat power generated by the fusion reaction), usually at the level of hundreds of megawatts (MW) to gigawatts (GW). At present, it is generally believed that two different physical mechanisms determine the radial transport, namely, radial transport dominated by drift and radial transport dominated by turbulence. For fusion devices with larger sizes, the drift-dominated effect is smaller, and it is easier to enter the turbulence-dominated situation. For the turbulence-dominated situation, it is the vertical particles and energy transport system that determine its heat flow width. According to relevant research on the international thermonuclear fusion ITER device, its heat flow width is very narrow. The heat flow width of the ITER device is 1-3mm. If no other optimization treatment methods are performed, the heat load deposited on the target plate is sufficient to cause erosion or melting of the target plate.

[0004] As the operating power of the fusion device increases, the heat load on the target plate will increase dramatically and exceed the existing engineering limit of the target plate material. At present, for low-power or general-power fusion devices, the particle flow and energy flow flowing from the core to the edge and then deposited in the divertor area will also exceed the engineering limit of the target plate material by 10MWm -2 Once the operation time is too long or the heat load on the target plate exceeds this limit, the target plate will be corroded or melted. This is extremely unfavorable for achieving long-term steady-state operation of the device. On the one hand, it will cause damage to the target plate and reduce its service life; on the other hand, it will cause impurities generated by the target plate to be transported to the core area, causing the discharge to extinguish.

[0005] In summary, how to reduce the heat load on the target plate has become one of the biggest challenges facing the development of divertor. The existing solutions and implementation technologies for the problem of heat load control of divertor in fusion tokamak devices mainly include:

[0006] (1) Configuration optimization technology that changes the magnetic field configuration structure of the device. This technology is to reduce the peak heat load of the target plate by increasing the contact area between the plasma particle flow and the target plate. Its basic principle is: for fixed plasma parameters, that is, considering the same heat flux bombardment, the larger the effective area of ​​the target plate that bears the heat load bombardment, the more conducive it is to control the peak heat load of the target plate in theory. In addition, there is currently a divertor configuration with double X points, as well as snowflakes and super X divertors developed in the past decade. These divertor configurations are all aimed at alleviating the heat load of the divertor target plate as much as possible. At present, advanced divertors are widely used, but the production of such divertor structures requires adding one or two pairs of poloidal field coils in the space of the divertor lower cavity to help generate additional X points. This technology has many challenges, limitations and drawbacks in practical applications, including: First, the distance between the added coils is relatively close, and the heat flux bombardment area of ​​the divertor target plate or the expansion of the magnetic surface cannot be increased infinitely; Second, the added coils are close to the divertor target plate, which will lead to insufficient design space for the divertor, especially for the tokamak fusion device. At the same time, this will make it difficult to optimize the operation mode or control the heat load through the divertor design; Third, there are many factors that need to be compatible and considered in engineering design, and the coil layout cannot be carried out according to theoretical calculations. Therefore, the realization of this type of divertor configuration puts extremely high requirements on engineering design, and still faces many challenges and limitations in practical applications; Fourth, relying on this type of optimized divertor configuration, it will theoretically help increase the plasma deposition area of ​​the outer target plate, and the heat load can be alleviated to a certain extent, but the heat load of the inner divertor target plate is difficult to be effectively alleviated. In summary, the configuration optimization technology can help to alleviate the heat load of the outer divertor to a certain extent, but the heat load of the inner side cannot be solved synchronously. In addition, this technology is not only difficult to implement in engineering design and practice, but also has the disadvantages of affecting the design and layout of the divertor target plate.

[0007] (2) Enhance the energy dissipation in the divertor region by injecting external impurities to further reduce the heat load deposited on the target plate. This method is an external means that can be used after completing the configuration optimization and divertor design. At present, the main inert gases used are nitrogen (N), neon (Ne) and argon (Ar). When these gases are injected into the running plasma, they will dissipate excess energy through linear radiation. At the same time, they will lose electrons and enter different charge states. This method can certainly help control the heat load of the divertor. However, there are also certain disadvantages and limitations: First, according to the introduction of this method, it is obvious that other particles (usually called impurities) besides fuel particles will be generated in the fusion device, and the presence of impurities may be transported to the area above point X or even the core area where the fusion reaction occurs, which will inevitably radiate the energy generated by the core, which is extremely unfavorable to the occurrence of the fusion reaction; second, if the concentration of impurity particles exceeds a certain limit, the plasma discharge will be instantly extinguished, which runs counter to the realization of long-pulse stable operation of the fusion device. In addition, the introduction of external impurities puts higher requirements on the impurity control and impurity removal in the divertor area. Moreover, in practice, external impurity injection requires a complete external injection system to be embedded in the device. This system not only needs to be engineered to be adapted to other engineering components, but also needs to be precisely controlled. In practice, this can be said to be fraught with difficulties. Summary of the invention

[0008] In view of the shortcomings and limitations of existing heat load control through configuration optimization technology and external impurity injection technology, this application proposes a divertor structure of a tokamak device and a design optimization method thereof. Based on the physical parameters and magnetic field topology of a compact fusion reactor, the physical structure design of the divertor is carried out. Combined with numerical simulation and evaluation technology, the thermal load of the divertor target plate, the level of neutral particles, the level of impurities, etc. are comprehensively considered to optimize the physical structure of the divertor, thereby obtaining the optimal divertor structure.

[0009] On the one hand, the present application is implemented through the following technical solutions:

[0010] A divertor structure design optimization method for a tokamak device, the divertor structure design optimization method comprising:

[0011] According to the geometric parameters and magnetic field topology of the compact fusion reactor, the short-leg wide slot divertor structure and the long-leg narrow slot divertor structure are designed respectively, and the striking point positions of the inner divertor and the outer divertor are determined;

[0012] Conducting a divertor target plate heat load evaluation and a neutral particle deposition evaluation under the same input conditions for the short-leg wide slot divertor structure and the long-leg narrow slot divertor structure, respectively, and determining an optimal divertor structure according to the evaluation results;

[0013] Under the same operating power conditions and the same upstream plasma density conditions, the divertor structures with different target plate opening and closing angles are designed with the strike point of the optimal divertor structure as the starting point;

[0014] By using numerical simulation technology, the thermal load and impurity level of the divertor target plate at different target plate opening and closing angles are obtained respectively, and the optimal target plate opening and closing angle of the optimal divertor structure is determined according to the thermal load and the impurity level.

[0015] In some embodiments, the divertor structure design optimization method further comprises:

[0016] The target plate edges in the inner divertor and the outer divertor close to the coil position are adjusted to be perpendicular to the coil edge.

[0017] In some embodiments, the designing of the short-leg wide slot divertor structure and the long-leg narrow slot divertor structure respectively, and determining the striking point positions of the inner divertor and the outer divertor specifically include:

[0018] According to the magnetic field topology of the compact fusion reactor, a divertor throat is established in combination with a curved top plate compatible with the lower cavity divertor coil and the shielding blanket designed to protect the coil structure below the X point; the divertor throat flows out from the core area to the edge area and further flows into the entrance area of ​​the divertor area;

[0019] A short-leg wide slot divertor structure and a long-leg narrow slot divertor structure are designed below the divertor throat bend, and the striking point coordinates of the inner divertor and the outer divertor are determined respectively.

[0020] In some embodiments, the step of respectively evaluating the divertor target plate heat load and neutral particle deposition of the short-leg wide slot divertor structure and the long-leg narrow slot divertor structure under the same input conditions, and determining the optimal divertor structure according to the evaluation results, specifically includes:

[0021] The upstream boundary conditions of the divertor are obtained by checking the basic parameters of the compact fusion reactor; the upstream boundary conditions of the divertor include: the power flowing from the core area to the edge area is 120MW; the upstream plasma density of the edge area is (3.0-4.0)×10 19 m -3 ; The density of helium particles flowing into the edge region is 2.5×10 18 m -3 ;The heat flow width is 0.9169mm;

[0022] Under the same input conditions, the peak value of the heat load of the outer target plate of the long-leg narrow slot divertor structure is smaller than the peak value of the heat load of the outer target plate of the short-leg wide slot divertor structure, and the peak value of the neutral particle density of the outer target plate of the long-leg narrow slot divertor structure is greater than the peak value of the neutral particle density of the outer target plate of the short-leg wide slot divertor structure;

[0023] According to the above evaluation results, it is determined that the long-legged narrow slot divertor structure is the optimal divertor structure.

[0024] In some embodiments, the design of divertor structures with different target plate opening and closing angles using the strike point of the optimal divertor structure as a starting point specifically includes:

[0025] Taking the striking point of the optimal divertor structure as the starting point, three different target plate opening and closing angles are designed, which are 20 degrees, 30 degrees and 40 degrees respectively.

[0026] In some embodiments, determining the optimal target plate opening and closing angle of the optimal divertor structure according to the heat load and the impurity level specifically includes:

[0027] The heat load and impurity level are relatively low, and taking into account the off-target effect and the difficulty of engineering implementation, the optimal target plate opening and closing angle of the optimal divertor structure is determined to be 30 degrees.

[0028] On the other hand, the present application also proposes a divertor structure of a tokamak device, and the divertor structure is designed using the above-mentioned divertor structure design optimization method.

[0029] In some embodiments, the divertor structure comprises: an inner divertor target plate, an outer divertor target plate, an inner divertor baffle and an outer divertor baffle;

[0030] Wherein, the inner divertor target plate and the outer divertor target plate are both long-legged narrow slot structures, and the target plate opening and closing angles of the inner divertor target plate and the outer divertor target plate are 30 degrees.

[0031] In some embodiments, the edges of the inner divertor target plate and the outer divertor target plate near the coil position are perpendicular to the coil edge;

[0032] The side walls of the inner divertor target plate and the outer divertor target plate have a certain thickness, which is about 10 to 15 cm.

[0033] In some embodiments, the divertor structure further includes: a slot structure for fitting and mounting the inner divertor target plate to the first wall, a slot structure for fitting and mounting the outer divertor target plate to the first wall, and an arc-shaped top plate compatible with the lower cavity divertor coil and the shielding layer.

[0034] The present application proposes a divertor structure of a tokamak device and a design optimization method thereof. Based on a compact fusion reactor, the physical structure of the divertor is designed, and the physical structure of the divertor is optimized in combination with numerical simulation and evaluation technology, thereby obtaining an optimal divertor structure. The optimal divertor structure can achieve effective control of the heat load while avoiding the disadvantages and limitations brought by the configuration optimization technology and the external impurity injection technology. In addition, in the design optimization process of the present application, the impurity injection and impurity removal effects are also considered, so that the optimal divertor structure also has a good impurity removal level and impurity shielding capability. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The drawings described herein are used to provide a further understanding of the embodiments of the present application, constitute a part of the present application, and do not constitute a limitation on the embodiments of the present application. In the drawings:

[0036] Figure 1 A flow chart of a method according to an embodiment of the present application;

[0037] Figure 2 The magnetic field topology for a compact fusion reactor;

[0038] Figure 3 For Figure 2 The divertor structure of the compact fusion reactor magnetic field topology shown: wherein (a) is a short-leg wide slot divertor structure, and (b) is a long-leg narrow slot divertor structure;

[0039] Figure 4 is the peak thermal load of the outer target plate of the divertor structure at 160MW fusion power;

[0040] Figure 5 is the peak value of neutral particle density of the outer target plate of the divertor structure at 160MW fusion power;

[0041] Figure 6 Long-legged narrow slot divertor structures with different target plate angles;

[0042] Figure 7 The peak value of the heat load of the outer target plate changes with the opening and closing angle of the target plate;

[0043] Figure 8 is the peak value of impurity level (effective charge) in the inner and outer divertor regions;

[0044] Fig. 9 The optimal divertor structure designed by the design optimization method proposed in this embodiment;

[0045] Fig.10 A comparison diagram of the helium exhaust efficiency of the cryopump between the long-legged narrow slot divertor structure designed by the design optimization method proposed in this embodiment and the existing short-legged wide slot divertor structure;

[0046] Reference numerals and corresponding component names:

[0047] 1-inner divertor target plate, 2-outer divertor target plate, 3-inner divertor baffle, 4-outer divertor baffle, 5-slot structure for matching and mounting the inner divertor target plate to the first wall, 6-slot structure for matching and mounting the outer divertor target plate to the first wall, 7-arc top plate, 11-target plate edge of the inner divertor target plate close to the coil position, 22-target plate edge of the outer divertor target plate close to the coil position, 10-core region, 20-X point, 30-outer divertor region, 40-inner divertor region, 50-edge region. DETAILED DESCRIPTION

[0048] Hereinafter, the term "include" or "may include" used in various embodiments of the present application indicates the presence of the invented function, operation or element, and does not limit the addition of one or more functions, operations or elements. In addition, as used in various embodiments of the present application, the terms "include", "have" and their cognates are intended only to indicate specific features, numbers, steps, operations, elements, components or a combination of the foregoing items, and should not be understood as first excluding the presence of one or more other features, numbers, steps, operations, elements, components or a combination of the foregoing items or the possibility of adding one or more features, numbers, steps, operations, elements, components or a combination of the foregoing items.

[0049] In various embodiments of the present application, the expression "or" or "at least one of A or / and B" includes any combination or all combinations of the words listed at the same time. For example, the expression "A or B" or "at least one of A or / and B" may include A, may include B, or may include both A and B.

[0050] The expressions (such as "first", "second", etc.) used in the various embodiments of the present application may modify the various constituent elements in the various embodiments, but may not limit the corresponding constituent elements. For example, the above expressions do not limit the order and / or importance of the elements. The above expressions are only used for the purpose of distinguishing one element from other elements. For example, the first user device and the second user device indicate different user devices, although both are user devices. For example, without departing from the scope of the various embodiments of the present application, the first element may be referred to as the second element, and similarly, the second element may also be referred to as the first element.

[0051] It should be noted that if it is described that one component element is “connected” to another component element, the first component element may be directly connected to the second component element, and a third component element may be “connected” between the first component element and the second component element. Conversely, when one component element is “directly connected” to another component element, it can be understood that there is no third component element between the first component element and the second component element.

[0052] The terms used in the various embodiments of the application are only used to describe the purpose of specific embodiments and are not intended to limit the various embodiments of the application. As used herein, the singular form is intended to also include the plural form, unless the context clearly indicates otherwise. Unless otherwise limited, all terms used here (including technical terms and scientific terms) have the same meaning as the meanings commonly understood by ordinary technicians in the field of the various embodiments of the application. The terms (such as the terms defined in the dictionary generally used) will be interpreted as having the same meaning as the contextual meaning in the relevant technical field and will not be interpreted as having an idealized meaning or an overly formal meaning, unless clearly defined in the various embodiments of the application.

[0053] In order to make the objectives, technical solutions and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with examples and drawings. The illustrative implementation scheme of the present application and its description are only used to explain the present application and are not intended to limit the present application.

[0054] Example:

[0055] The existing methods for alleviating the heat load deposited on the divertor mainly include configuration optimization technology and external impurity injection technology. These two methods have certain deficiencies, drawbacks and limitations. For example, the engineering and technical difficulties brought by the configuration optimization technology are that it is impossible to provide enough space to be compatible with the divertor design and other diagnostic equipment; the configuration optimization technology has limitations on the increase of the heat load bearing area of ​​the divertor target plate, and can only increase a certain plasma wetting area; and the engineering implementation process of the external impurity injection technology is extremely difficult; the external impurity injection technology puts forward higher requirements for the effective removal of impurities; in addition, the configuration optimization technology and the external impurity injection technology do not take into account the problems of particle removal, shielding and neutron irradiation of the fusion device that may be generated. In view of this, this embodiment proposes a divertor structure design optimization method for a tokamak device, adopts the optimization design of the divertor geometric structure, and obtains a long-legged narrow slot divertor structure that is compatible with the lower cavity of a compact fusion reactor. The divertor structure can achieve effective control of the heat load while avoiding the drawbacks and limitations brought by the configuration optimization technology and the external impurity injection technology.

[0056] like Figure 1As shown, the divertor structure design optimization method proposed in this embodiment specifically includes the following steps:

[0057] Step 100, according to geometric parameters and magnetic field topology related to the compact fusion reactor, design a short-leg wide slot divertor structure and a long-leg narrow slot divertor structure respectively, and determine the striking point positions of the inner divertor and the outer divertor.

[0058] The geometric parameters related to the compact fusion reactor include the position data of the first wall, coil, and blanket of the compact fusion reactor; the magnetic field topology is obtained according to the fixed coil and current ratio, such as Figure 2 The magnetic field topology of the compact fusion reactor is shown, wherein the area covered by the blue magnetic surface on the right below the X point 20 is the outer divertor area 30 , and the area covered by the blue magnetic surface on the left below the X point 20 is the inner divertor area 40 .

[0059] The design process of the short-leg wide slot divertor structure and the long-leg narrow slot divertor structure is as follows:

[0060] First, based on the magnetic field topology of the compact fusion reactor ( Figure 2 As shown in the figure, in particular, the divertor operation space of the lower cavity of the device, in order to make full use of the original magnetic field topological structure at the bend and the widening effect of the magnetic surface at the bend, combined with the arc-shaped top plate compatible with the divertor coil of the lower cavity and the shielding cladding designed to protect the coil structure below point X, establishes the divertor throat, which flows out from the core area to the edge area and further flows into the inlet area of ​​the divertor area, so as to enhance the particle circulation effect and the divertor closure.

[0061] Then, a short-leg wide slot divertor structure and a long-leg narrow slot divertor structure are designed below the throat bend of the divertor, and the intersection points of the outermost closed magnetic lines and the target plate, i.e., the coordinates of the striking points of the inner and outer divertors, are determined respectively (for the long-leg narrow slot structure, the fixed position of the small angle is the striking point position). Figure 3 Shown for Figure 2 The divertor structure of the compact fusion reactor magnetic field topology structure shown in FIG. 1 , wherein (a) is a short-leg wide slot divertor structure, and (b) is a long-leg narrow slot divertor structure. For the short-leg wide slot divertor structure, the coordinates of the inner and outer divertor strike points are: (2175, -4000), (3380, -4000); for the long-leg narrow slot divertor structure, the coordinates of the inner and outer divertor strike points are: (2396, -4318), (3104.18, -4318), in mm. Compared with the short-leg wide slot divertor structure, the long-leg narrow slot divertor structure has the inner and outer target plates sunk 318 mm along the longitudinal position, forming a long-leg narrow slot divertor structure.

[0062] Step 200 , respectively evaluating the divertor target plate heat load and neutral particle deposition of the short-leg wide slot divertor structure and the long-leg narrow slot divertor structure under the same input conditions, and determining the optimal divertor structure according to the evaluation results.

[0063] In step 200, the upstream boundary conditions of the divertor are obtained by checking the basic parameters of the compact fusion reactor device to facilitate the evaluation of the thermal deposition and neutral particle deposition of the divertor target plate. The corresponding boundary conditions include:

[0064] (1) The power flowing from the core region to the edge region is P CIB =120MW (meeting the first-stage steady-state operation design power of the compact nuclear fusion reactor, corresponding to fusion energy of 160MW);

[0065] (2) The upstream plasma density in the edge region is n sep =(3.0~4.0)×10 19 m -3 (Satisfying the core plasma confinement conditions);

[0066] (3) The density of helium particles flowing into the edge region is 2.5×10 18 m -3 ;

[0067] (4) The heat flux width λ under the operating conditions is calculated using the internationally recognized heat flux width calibration formula based on the plasma current and other device dimensions. q Approximately equal to 0.9169mm.

[0068] Get as Figure 4 and Figure 5 The evaluation results shown are: Figure 4 The peak thermal load of the outer target plate of the short-leg wide slot divertor structure and the long-leg narrow slot divertor structure at 160MW fusion power is shown. Figure 5 The peak values ​​of neutral particle density of the outer target plate of the short-leg wide slot divertor structure and the long-leg narrow slot divertor structure at 160MW fusion power are shown. Figure 4 and Figure 5 It can be seen that under the same input conditions, the peak heat load of the outer target plate of the long-legged slot divertor structure (about 25MWm -2 ) is much lower than the peak heat load of the outer target plate of the short-leg wide-slot divertor structure (about 50MWm -2 ), and the peak value of neutral particle density of the outer target plate of the long-legged narrow slot divertor structure (about 5×10 17 m -3 ) is much larger than the peak value of neutral particle density of the outer target plate of the short-leg wide-slot divertor structure (about 2.5×10 17 m -3). According to the evaluation results, this embodiment determines the long-legged narrow slot divertor structure as the optimal divertor structure. It is particularly emphasized that for the current international and domestic reactor-level fusion devices, when the fusion power reaches 150MW, the heat load can be reduced to 25MWm only by designing the divertor target plate. -2 Therefore, the long-legged narrow slot divertor structure proposed in this embodiment makes full use of the long legs and the large magnetic surface expansion width to achieve ultra-high heat load control capability. In addition, the peak density of neutral particles also fully demonstrates the scientific reliability of the long-legged narrow slot divertor structure design. It should be noted that in this embodiment, Figure 4 and Figure 5 The thermal load peak value and the neutral particle density peak value are mainly used as typical values ​​to illustrate the design optimization method proposed in this embodiment, but are not limited thereto. As long as the thermal load, neutral particle density, etc. are considered when designing the physical structure of the divertor, the structure with better thermal load and neutral particle density conditions can be selected as the optimal divertor structure.

[0069] Step 300 , under the same operating power conditions and the same upstream plasma density conditions, the divertor structures with different target plate opening and closing angles are designed with the strike point of the optimal divertor structure as the starting point.

[0070] In step 300, this embodiment designs three different target plate opening and closing angles, which are 20 degrees, 30 degrees and 40 degrees respectively. Figure 6 As shown, the three long-legged narrow slot divertor structures with different target plate opening and closing angles have the same strike point position coordinates but different target plate opening and closing angles. It should be noted that the above design is only an exemplary description and does not limit the target plate opening and closing angle. In other optional embodiments, other numbers and target plate opening and closing angles of other angles can also be designed for numerical simulation. In addition, according to the computing power of the hardware equipment and the corresponding accuracy requirements, a more refined design can be carried out. For example, within the preset angle range, more target plate opening and closing angles can be obtained according to the preset step size (such as 1 degree, 2 degrees, etc.). The smaller the preset step size, the higher the accuracy, the larger the corresponding numerical calculation amount, and the lower the processing efficiency; on the contrary, the larger the preset step size, the lower the accuracy, the smaller the corresponding numerical calculation amount, and the higher the processing efficiency.

[0071] Step 400, using numerical simulation technology, respectively obtain the thermal load and impurity level of the divertor target plate at different target plate opening and closing angles, and determine the optimal target plate opening and closing angle of the optimal divertor structure according to the thermal load and the impurity level.

[0072] In step 400, numerical simulation calculations are performed on the long-legged narrow slot divertor structures with three different target plate opening and closing angles to obtain corresponding numerical simulation results, such as Figure 7 and Figure 8 As shown. Among them, Figure 7 The peak values ​​of the thermal load of the outer target plate at three different target plate opening and closing angles are shown. Figure 7 It can be seen that the peak value of the heat load of the outer target plate increases with the increase of the target plate opening angle. When the target plate opening angle is 20 degrees, the peak value of the heat load of the outer target plate is about 21MW m -2 At a target plate opening angle of 30 degrees, the peak value of the heat load on the outer target plate is about 25m -2 At a target plate opening angle of 40 degrees, the peak value of the heat load on the outer target plate is about 35m -2 . Figure 8 The peak values ​​of impurity levels (peak values ​​of effective charge) in the inner and outer divertor regions at three different target plate opening and closing angles are shown. Figure 8 It can be seen that the peak impurity levels in the inner and outer divertor regions (i.e., taking into account the impurity levels in the inner and outer divertor regions and taking the maximum value therebetween) increase with the increase of the target plate opening angle. At a target plate opening angle of 20 degrees, the peak impurity levels in the inner and outer divertor regions are about 1.5, at a target plate opening angle of 30 degrees, the peak impurity levels in the inner and outer divertor regions are about 1.7, and at a target plate opening angle of 40 degrees, the peak impurity levels in the inner and outer divertor regions are about 2. It can be seen that from the perspective of heat load control and impurity level control, a target plate opening angle of 20 degrees is optimal. However, due to the divertor structure with a target plate opening angle of 20 degrees, it will cause the over-and-off target effect of the divertor, and the engineering implementation is extremely difficult. Therefore, this embodiment preferably uses a long-legged narrow slot divertor structure with a target plate opening angle of 30 degrees, which can effectively reduce the heat load of the target plate and effectively shield the impurities. It should be noted that in this embodiment, Figure 7 and Figure 8 The design optimization method proposed in this embodiment is mainly illustrated by taking the heat load peak value and the impurity level peak value as typical values, but is not limited thereto. As long as the heat load, impurity level, etc. are considered when designing the physical structure of the divertor, the angle with better heat load and impurity level (while considering other factors, such as the difficulty of engineering implementation, etc.) is selected as the optimal divertor target plate opening and closing angle of the optimal divertor structure.

[0073] Furthermore, in order to enhance the impurity removal capability, the divertor structure design optimization method proposed in this embodiment further includes:

[0074] Step 500, adjust the target plate edge near the coil position in the inner and outer divertors to be perpendicular to the coil edge, so as to ensure the impurity removal capability in the subsequent actual operation process.

[0075] In this embodiment, the target plate edge near the coil position in the inner divertor and the outer divertor is adjusted to be perpendicular to the coil edge to enhance the impurity removal capability. Fig. 9 The long-legged slot divertor structure shown.

[0076] like Fig. 9 As shown, the divertor structure obtained by the above-mentioned design optimization method in this embodiment mainly includes: an inner divertor target plate 1, an outer divertor target plate 2, an inner divertor baffle 3, an outer divertor baffle 4, a slot structure 5 for the inner divertor target plate 1 to be adapted and installed with the first wall, a slot structure 6 for the outer divertor target plate 2 to be adapted and installed with the first wall, and an arc-shaped top plate 7 compatible with the lower cavity divertor coil and the shielding layer.

[0077] Among them, the inner divertor target plate 1 and the outer divertor target plate 2 are both long-leg narrow slot structures, the target plate opening and closing angles of the inner divertor target plate 1 and the outer divertor target plate 2 are preferably 30 degrees, and the target plate edges (i.e., 11 and 22) of the inner divertor target plate 1 and the outer divertor target plate 2 close to the coil position are perpendicular to the coil edge.

[0078] The long-legged narrow slot divertor structure designed in this embodiment forms a closed outlet position formed by the inner divertor target plate 1, the outer divertor target plate 2 and their corresponding baffles, which can improve the neutral particle circulation effect and enhance the particle removal ability. The side walls of the inner and outer divertor target plates have a certain thickness of about 10 to 15 cm. Cooling pipes can be designed inside to guide excess heat in engineering practice to reduce the temperature of components and avoid damage to components due to high temperature. In addition, the inner divertor baffle 3 and the outer divertor baffle 4 also provide a certain space for the subsequent installation of the gas injection port.

[0079] In addition, the long-legged narrow slot divertor structure (i.e., Fig. 9 The divertor structure shown in FIG. 1 is compared with the short-leg wide-slot divertor structure. The two divertor structures are tested for helium impurity removal under the same conditions. The results are as follows: Fig.10 The comparison of the helium particle flow reaching the vacuum pump of the two divertor structures shown in Figure 1 varies with the vacuum pump pumping rate. Fig.10 It can be seen that the helium particle flow reaching the pump of the two divertor structures increases first, then decreases, and then increases again with the increase of the pumping rate, indicating that the helium particle flow reaching the pump of the two divertor structures has the same trend with the pumping rate of the pump. In actual engineering design, the pumping rate that the pump can achieve is generally 200m / s. 3 s -1 For the long-legged narrow slot divertor structure, the best air extraction efficiency (i.e., the maximum particle flow) that can be achieved corresponds to an air extraction pump speed of about 175m 3 s -1 For the short-leg wide-slot divertor structure, the best air extraction efficiency (i.e., the maximum particle flow) that can be achieved corresponds to an air extraction pump speed of about 125 m / s. 3 s -1 In addition, under the same heating power and core parameter conditions, the helium particle flow from the long-legged narrow slot divertor structure to the pump is 5×1019 s -1 The helium particle flow reaching the pump from the short-leg wide-slot divertor structure is 4×10 19 s -1 .

[0080] In summary, compared with the short-leg wide-slot divertor structure, the long-leg narrow-slot divertor structure has an efficiency of about 25% in removing helium impurities.

[0081] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application may adopt the form of a computer program product implemented in one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that include computer-usable program code.

[0082] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0083] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0084] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0085] The specific implementation methods described above further illustrate the purpose, technical solutions and beneficial effects of the present application in detail. It should be understood that the above description is only the specific implementation method of the present application and is not intended to limit the scope of protection of the present application. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present application should be included in the scope of protection of the present application.

Claims

1. A method for optimizing the divertor structure design of a tokamak device, characterized in that: The divertor structure design optimization method comprises: According to the geometric parameters and magnetic field topology of the compact fusion reactor, the short-leg wide slot divertor structure and the long-leg narrow slot divertor structure are designed respectively, and the striking point positions of the inner divertor and the outer divertor are determined; Conducting a divertor target plate heat load evaluation and a neutral particle deposition evaluation under the same input conditions for the short-leg wide slot divertor structure and the long-leg narrow slot divertor structure, respectively, and determining an optimal divertor structure according to the evaluation results; Under the same operating power conditions and the same upstream plasma density conditions, the divertor structures with different target plate opening and closing angles are designed with the strike point of the optimal divertor structure as the starting point; By using numerical simulation technology, the thermal load and impurity level of the divertor target plate at different target plate opening and closing angles are obtained respectively, and the optimal target plate opening and closing angle of the optimal divertor structure is determined according to the thermal load and the impurity level.

2. The method for optimizing the divertor structure design of a tokamak device according to claim 1, characterized in that: The divertor structure design optimization method further comprises: The target plate edges in the inner divertor and the outer divertor close to the coil position are adjusted to be perpendicular to the coil edge.

3. The method for optimizing the divertor structure design of a tokamak device according to claim 1 or 2, characterized in that: The design of the short-leg wide slot divertor structure and the long-leg narrow slot divertor structure respectively, and determining the striking point positions of the inner divertor and the outer divertor specifically include: According to the magnetic field topology of the compact fusion reactor, a divertor throat is established in combination with a curved top plate compatible with the lower cavity divertor coil and the shielding blanket designed to protect the coil structure below the X point; the divertor throat flows out from the core area to the edge area and further flows into the entrance area of ​​the divertor area; A short-leg wide slot divertor structure and a long-leg narrow slot divertor structure are designed below the divertor throat bend, and the striking point coordinates of the inner divertor and the outer divertor are determined respectively.

4. A method for optimizing the divertor structure design of a tokamak device according to claim 1 or 2, characterized in that: The method of respectively evaluating the divertor target plate heat load and neutral particle deposition of the short-leg wide slot divertor structure and the long-leg narrow slot divertor structure under the same input conditions, and determining the optimal divertor structure according to the evaluation results, specifically includes: The upstream boundary conditions of the divertor are obtained by checking the basic parameters of the compact fusion reactor; the upstream boundary conditions of the divertor include: the power flowing from the core area to the edge area is 120MW; the upstream plasma density of the edge area is (3.0-4.0)×10 19 m -3 ; The density of helium particles flowing into the edge region is 2.5×10 18 m -3 ;The heat flow width is 0.9169mm; Under the same input conditions, the peak value of the heat load of the outer target plate of the long-leg narrow slot divertor structure is smaller than the peak value of the heat load of the outer target plate of the short-leg wide slot divertor structure, and the peak value of the neutral particle density of the outer target plate of the long-leg narrow slot divertor structure is greater than the peak value of the neutral particle density of the outer target plate of the short-leg wide slot divertor structure; According to the above evaluation results, it is determined that the long-legged narrow slot divertor structure is the optimal divertor structure.

5. A method for optimizing the divertor structure design of a tokamak device according to claim 1 or 2, characterized in that: The divertor structures with different target plate opening and closing angles are designed by taking the striking point of the optimal divertor structure as the starting point, specifically comprising: Taking the striking point of the optimal divertor structure as the starting point, three different target plate opening and closing angles are designed, which are 20 degrees, 30 degrees and 40 degrees respectively.

6. The method for optimizing the divertor structure design of a tokamak device according to claim 5, characterized in that: The step of determining the optimal target plate opening and closing angle of the optimal divertor structure according to the heat load and the impurity level specifically includes: The heat load and impurity level are relatively low, and taking the off-target effect and the difficulty of engineering implementation into consideration, the optimal target plate opening and closing angle of the optimal divertor structure is determined to be 30 degrees.

7. A divertor structure of a tokamak device, characterized in that: The divertor structure is designed by using the divertor structure design optimization method described in any one of claims 1 to 6.

8. The divertor structure of a tokamak device according to claim 7, characterized in that: The divertor structure comprises: an inner divertor target plate, an outer divertor target plate, an inner divertor baffle and an outer divertor baffle; Wherein, the inner divertor target plate and the outer divertor target plate are both long-legged narrow slot structures, and the target plate opening and closing angles of the inner divertor target plate and the outer divertor target plate are 30 degrees.

9. The divertor structure of a tokamak device according to claim 8, characterized in that: The edges of the target plates of the inner divertor target plate and the outer divertor target plate close to the coil position are perpendicular to the edge of the coil; The side walls of the inner divertor target plate and the outer divertor target plate have a certain thickness, which is about 10 to 15 cm.

10. The divertor structure of a tokamak device according to claim 7, characterized in that: The divertor structure further comprises: a slot structure for the inner divertor target plate to be adapted and installed with the first wall, a slot structure for the outer divertor target plate to be adapted and installed with the first wall, and an arc-shaped top plate compatible with the lower cavity divertor coil and the shielding layer.

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