Patent Description:
As a core component inside the tokamak fusion device, a first wall of a divertor is required to withstand the bombardment of high-energy particles from the plasma core. In this case, a heat load ranging from several MW/m<NUM> to tens of MW/m<NUM> will be formed on the surface. The generated energy will be removed through the inner cooling water flow, otherwise will affect the normal operation of the divertor, and may even lead to a failure.

At present, most divertors, such as International Thermonuclear Experimental Reactor (ITER) divertor, adopt a separate first wall (as shown in <FIG>) mostly, which often includes inner target, inner reflector plate, dome, outer reflector plate and outer target. For other diverters, such as Experimental Advanced Superconducting Tokamak (EAST) divertor, their first walls are commonly designed based on the above structure. Individual parts of the separate structure need to be connected via the inlet and outlet water joints (water cassette), and then a cooling water loop is enabled to cool the components. Due to the intersection with the scrape-off layer (region between the last closed flux surface and the last open flux surface of the plasma region), the target is subjected to high heat load. Moreover, since the plasma configuration is unstable during operation, the bombardment caused by the high-energy particles will be likely to be transmitted to the water joints (water cassette). Unfortunately, due to the poor heat transfer capacity, the water joints (water cassette) are inferior to the target in the heat load bearing capacity, failing to withstand the heat load generated by the bombardment of the plasma. Therefore, it is prone to result in the end effect, thereby making it not conducive to the flexible adjustment of the plasma configuration.

There is known [<NPL>] provides a meticulous examination of factors integral to the optimization of divertor performance within the context of sustainable and efficacious fusion technologies. The absence of a detailed exploration of specific material and manufacturing solutions diminishes the practical applicability of the findings.

There is also known a patent application [<CIT>] wherein is disclosed fusion reactor divertor structure for front remote operation and maintenance. It comprises a plasma facing component with inner and outer target plate areas, and a box body support with a main cooling water pipe.

In view of the defects in the prior art, some structural optimizations have been made to the first wall of the diverter, and a closed V-shaped acute-angle structure for the first wall is provided herein, in which the channels are removed to avoid the end effect. The target has the same structure parameters with the reflector plate, such that they share the same heat transfer capacity in the V-shaped acute-angle region, satisfying the flexible adjustment of the plasma configuration and enhancing the operation safety of the device.

Technical solutions of this application are described as follows.

In an embodiment, a closed V-shaped acute-angle structure for a first wall of a divertor for tokamak fusion devices, comprising:.

In an embodiment, the target and the reflector plate are the same in structure and parameter of each layer, such that the target and the reflector plate have the same heat transfer capacity, so as to satisfy the requirement of heat load capacity in the plasma strike-point area under different plasma configurations. The tungsten layer is configured to be exposed to plasma; the copper layer is configured as a transition layer; the chromium-zirconium-copper layer is configured as a heat transfer layer; the stainless-steel layer is configured as a structural layer; and the stainless-steel cover plate is configured as a cover plate for the HyperVapotron cooling water channel.

In an embodiment, tungsten layers of the target and the reflector plate are located at an inner side of the closed V-shaped acute-angle structure, and have an overlapping area at a root of the closed V-shaped acute-angle structure so as to ensure that a plasma strike-point area is fully covered by the tungsten layer to allow the plasma to be completely intercepted by the tungsten layer.

In an embodiment, the HyperVapotron cooling water channel covers the chromium-zirconium-copper layer, the stainless-steel layer and the stainless-steel cover plate. At a chromium-zirconium-copper layer side in a welding area of the closed V-shaped acute-angle structure, the HyperVapotron cooling water channel experiences a transition in a sequence of the chromium-zirconium-copper layer-a chromium-zirconium-copper and stainless-steel mixed layer-the stainless-steel layer. The stainless-steel cover plate and the stainless layer are sealedly welded to form the complete HyperVapotron cooling water channel. A plurality of grooves are provided inside the chromium-zirconium-copper layer and the stainless-steel layer. The chromium-zirconium-copper layer and the stainless-steel layer are composite panels pre-formed by related processes (e.g., explosive welding), and then are processed to form the plurality of grooves inside, wherein the chromium-zirconium-copper layer is configured for heat transfer, and the stainless-steel layer is configured to provide structural strength. The above designed transition from the chromium-zirconium-copper layer to the stainless-steel layer in the welding area can effectively avoid the occurrence of welding defects between different materials. Moreover, the welding between the pure stainless-steel layers can enhance the welding strength of interfaces between the target and the reflector plate.

In an embodiment, the target and the reflector plate are butt welded by a one-step butt-welding forming which contains welding of stainless-steel layers of the target and the reflector plate, welding of the stainless-steel cover plate and the stainless-steel layer, the welding of the cooling water pipe and the stainless-steel cover plate and welding of the tungsten-copper sheet and the chromium-zirconium-copper layer. The tungsten copper sheet comprising the tungsten layer and the copper layer has been pre-formed via other processes (e.g., casting).

In an embodiment, the welding area is a welding interface formed by butt welding between stainless-steel layers of the target and the reflector plate. The welding interface has a boss and a recess matched with each other, which are strictly controlled in terms of the tolerance. A mutually matching boss-recess structure is also suitable for welding interfaces between the stainless-steel cover plate and the stainless-steel layer and welding interfaces between the cooling water pipe and the stainless-steel cover plate. The mutually matching boss-recess structure is intended to improve the positioning accuracy of assembly and enhance the welding strength.

Compared with the prior art, this application has the following beneficial effects.

Regarding the closed V-shaped acute-angle structure designed herein, the end effect is effectively eliminated, and thus the operation safety of the whole device is enhanced. The target and the reflector plate have the same heat transfer capacity to enable the flexible adjustment and control of the plasma strike points between the target and the reflector plate, so as to satisfy the flexibility requirement of the plasma configuration, promoting the physical research on the exploration and development of advanced divertors. In addition, the closed V-shaped acute-angle structure is more conducive to obtaining the operation mode of the radiative divertor, and reducing the heat load on the target. The internal HyperVapotron cooling water channel improves the heat transfer efficiency and significantly enhances the heat load capacity.

In the drawings: <NUM>: plasma configuration line; <NUM>: target; <NUM>: cooling water channel; <NUM>: corrugated connection pipe; <NUM>: channel; <NUM>: dome; <NUM>: cooling water pipe; <NUM>: target; <NUM>: tungsten layer; <NUM>: copper layer; <NUM>: chromium-zirconium-copper layer; <NUM>: stainless-steel layer; <NUM>: groove; <NUM>: first boss; <NUM>: stainless-steel cover plate; <NUM>: second boss; <NUM>: HyperVapotron cooling water channel; <NUM>: welding interface; <NUM>: reflector plate; and <NUM>: overlapping area.

With reference to the accompanying drawings and embodiments of this application, the technical solutions of the present application will be clearly and completely described below. Obviously, described below are merely some embodiments of the present application, which are not intended to limit the application. Other embodiments obtained by those of ordinary skill in the art based on these embodiments without paying creative effort shall fall within the scope of the present application.

Referring to an embodiment shown in <FIG>, a closed V-shaped acute-angle structure for a first wall of a divertor is proposed, including a target <NUM>, a reflector plate <NUM>, a stainless-steel cooling water pipe <NUM>, and the like. The target <NUM> and the reflector plate <NUM> are butt welded to form the V-shaped acute-angle structure. The target <NUM> and the reflector plate <NUM> are each processed to have a HyperVapotron cooling water channel <NUM> inside. The cooling water pipe <NUM> is communicated with the HyperVapotron cooling water channel <NUM> to form a cooling water channel system inside the first wall.

An exploded diagram of the closed V-shaped acute-angle structure is shown in <FIG>. Each of the target <NUM> and the reflector plate <NUM> includes a tungsten layer <NUM>, a copper layer <NUM>, a chromium-zirconium-copper layer <NUM>, a stainless-steel layer <NUM> and a stainless-steel cover plate <NUM> connected in sequence. The tungsten layers <NUM> of the target <NUM> and the reflector plate <NUM> are located at an inner side of the V-shaped acute-angle structure. High-energy particles bombard the tungsten layer <NUM> within the range covered by the plasma configuration line <NUM>. A generated heat is conducted to the tungsten layer <NUM> through the copper layer <NUM>, as a transition layer, to the chromium-zirconium-copper layer <NUM> and taken away by a flowing cooling liquid in the HyperVapotron cooling water channel <NUM>.

The HyperVapotron cooling water channel <NUM> is covered with the chromium-zirconium-copper layer <NUM>, the stainless-steel layer <NUM> and the stainless-steel cover plate <NUM>. The chromium-zirconium-copper layer <NUM> and the stainless-steel layer <NUM> are fixedly connected by explosion welding. At the same time, a plurality of grooves are provided inside the chromium-zirconium-copper layer <NUM> and the stainless-steel layer <NUM>. The chromium-zirconium-copper layer <NUM> enables to quickly conduct heat to the cooling liquid in the HyperVapotron cooling water channel <NUM>. The stainless-steel layer <NUM> is configured to provide structural strength.

Referring to an embodiment shown in <FIG>, in a welding area of the V-shaped acute-angle structure, on a side of the chromium-zirconium-copper layer <NUM>, the HyperVapotron cooling channel <NUM> experiences a transition in a sequence of the chromium-zirconium-copper layer <NUM>-chromium-zirconium-copper layer and stainless-steel mixed layer-pure stainless-steel layer <NUM> to ensure that the target <NUM> is welded with the reflector plate <NUM> via the welding between the pure stainless-steel layers <NUM>, avoiding welding defects between different materials and improving the welding strength. A welding interface <NUM> between the stainless-steel layers <NUM> is processed into a structure of a first boss <NUM> and a groove <NUM> matched with each other, and the processing accuracy is strictly controlled, which facilitates the improvement of positioning accuracy during the welding of assembly and the enhancement of the welding strength. The mutually matching boss-recess structure is also suitable for welding interfaces between the stainless-steel cover plate <NUM> and the stainless-steel layer <NUM> and welding interfaces between the cooling water pipe <NUM> and the stainless-steel cover plate <NUM>.

At a root of the V-shaped acute-angle structure, when assembling before welding, the tungsten layers <NUM> of the target <NUM> and the reflector plate <NUM> have a partial overlapping area <NUM> in a transmission direction of the plasma configuration line <NUM> to ensure high-energy particles running along the plasma configuration line <NUM> to be completely intercepted by the tungsten layer <NUM>.

With regard to the closed V-shaped acute-angle structure for the first wall of the divertor provided herein, both of the target <NUM> and the reflector plate <NUM> have the same heat transfer capacity, and the plasma strike points can be flexibly adjusted and controlled between the target <NUM> and the reflector plate <NUM>, satisfying the flexibility requirement of plasma configuration, and promoting the exploration and development of the physical research on advanced divertors.

Claim 1:
A closed V-shaped acute-angle structure for a first wall of a divertor for tokamak fusion devices, comprising:
a target (<NUM>);
a reflector plate (<NUM>); and
a cooling water pipe (<NUM>);
wherein the target (<NUM>) and the reflector plate (<NUM>) both have a flat-plate structure, and each comprises a tungsten layer (<NUM>), a copper layer (<NUM>), a chromium-zirconium-copper layer (<NUM>), a stainless-steel layer (<NUM>) and a stainless-steel cover plate (<NUM>) connected in sequence; the chromium-zirconium-copper layer, the stainless-steel layer and the stainless-steel cover plate (<NUM>) are combined to form a heat sink; the chromium-zirconium-copper layer and the stainless-steel layer inside the heat sink form a HyperVapotron cooling water channel (<NUM>); and the cooling water pipe (<NUM>) is communicated with the HyperVapotron cooling water channel (<NUM>)to form a cooling water channel;
characterized in that the target (<NUM>) and the reflector plate (<NUM>) are butt welded to form the closed V-shaped acute-angle structure to allow flexible adjustment and control of plasma strike points between the target (<NUM>) and the reflector plate (<NUM>), so as to enable flexible adjustment of plasma configuration.