JPS6251435B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a divertor for a nuclear fusion device, and more particularly to a divertor for a nuclear fusion device in which a diverter plate with which high-energy impurity particles collide is improved in order to remove impurity particles in plasma.

Generally, in a nuclear fusion device, for example, a tokamak type fusion device, a diverter is provided in a vacuum vessel for the purpose of removing impurity particles in plasma and α particles produced as a result of a nuclear fusion reaction.

This divertor is usually composed of a diverter coil and a diverter plate, and in order to remove impurity particles, high-energy impurity particles induced by a magnetic field from high-temperature plasma collide with the divertor plate. For this reason, the diverter plate is heated to a high temperature, and the divertor plate that has been heated to a high temperature must be cooled down by some method. Conventionally, the diverter plate that collides with impurity particles and the cooling system outside the vacuum vessel are connected via cooling piping.
The diverter plate is forcibly cooled by a cooling system.

As mentioned above, the surface of the diverter plate is gradually damaged by the collision of impurity particles and the sputtering phenomenon caused by the irradiation of the high-energy particle stream, so that it must be replaced from time to time.

However, as mentioned above, the diverter plate is connected to the external cooling system through the cooling piping, so when replacing the diverter plate, the damaged diverter plate must be disconnected from the cooling piping, and , which involves reconnecting the cooling piping after installing a new diverter plate. Moreover, the area around the connection between the divertor plate and the cooling pipe is not only in ultra-high vacuum but also in high temperature when operating the fusion device, so the structure of this connection is limited to ordinary O-rings and seals. Mechanical pipe joints using pipe materials are unreliable and unusable, and there is no other suitable method other than welded joints that meet the above conditions, and these welded joints are usually used. However, in the case of welded joints, cutting and welding at the same location many times not only takes time, but also leaves many problems, such as the need for non-destructive testing to prevent leakage from the welded parts. There is.

In this way, in the conventional configuration, since it is a fusion device, the diverter plate, which has severe connection conditions, can be damaged and requires complicated work to replace. desired.

The present invention has been made in view of the above points, and its purpose is to eliminate the need for disconnecting and reconnecting cooling pipes even when replacing a damaged portion of a diverter plate. An object of the present invention is to provide a divertor for a nuclear fusion device, which efficiently transfers heat flow caused by impurity particles incident on the surface of a diverter plate and improves the cooling effect.

The present invention provides a blanket which is arranged in a vacuum container in which a plasma is confined, so as to surround the plasma, and which constitutes a diverter chamber in a part of the plasma side, and which is arranged in the diverter chamber of the blanket to surround the plasma. A plurality of diverter plates that collide and remove impurity particles are configured by integrating a cooling plate connected to a cooling pipe and a cover plate removably provided on the plasma side of the cooling plate, and the cover plate is , a space is formed inside the space, a thin metal plate is arranged to cover the space, and a low melting point metal or a volatile liquid and a metal flocculent are sealed in the space. By doing so, the intended purpose was achieved.

The present invention will be described in detail below based on embodiments shown in the drawings.

FIG. 1 is a schematic partial cross-sectional view of the fusion device, showing the arrangement of the diverter plates. The configuration will be explained using the figure.

A blanket 2 is arranged so as to surround the plasma 1, and a part of the blanket 2 is inflated to form a diverter chamber 3. A cooling plate 4 and a cover plate 5 constituting a diverter plate in this diverter chamber 3
is fixedly installed on the blanket 2 by a stay 10, and a cover plate 5 is installed, the detailed configuration will be described later.
It is integrated with the cooling plate 4 so that it faces the plasma 1 side. The cooling plate 4 is connected to an external coolant circulation device 6.
There is a vacuum container 8 on the outside of the blanket 2, but the cooling pipe 7
penetrates the wall of the vacuum vessel 8. Although the interior of the vacuum container 8 is evacuated, the penetrating portion of the cooling pipe 7 is vacuum-sealed. Note that 9 is an impurity particle guided from the plasma 1 to the diverter chamber 3.

Next, details of the diverter plate of this embodiment will be explained using FIG. 2.

The diverter plate arranges a plurality of cooling plates 4,
A cover plate 5 is attached to each cooling plate 4, and when the cover plate 5 is attached, the surface thereof becomes a conical surface. The cover plate 5 is removably tightly fixed to each cooling plate 4 by bolts 11 and integrated, and each cooling plate 4 is integrated with the cover plate 5.
is fixed to the blanket 2 by a stay 10.
This cooling plate 4 is connected to a cooling pipe 7 and is cooled by an external coolant circulation device 6.

In the diverter of this embodiment configured as described above, the impurity particles 9 guided from the plasma 1 to the diverter chamber 3 collide with the cover plate 5, causing damage to the cover plate 5 due to high heat or sputtering on the surface, resulting in replacement. If it becomes necessary,
Replacement is completed by simply removing the bolts 11 of the cover plate 5 that needs to be replaced, removing the cover plate 5 from the cooling plate 4, and tightening the new cover plate 5 with the bolts 11. The work of disconnecting and reconnecting is completely eliminated. Therefore, there is no need to cut the cooling pipe 7 for replacement as in the past, and all processes such as cutting the cooling pipe 7, preparing a bevel, welding to size, and non-destructive inspection can be omitted, making the replacement work easier. Time is significantly reduced. In addition, due to a defect in the connection between the diverter plate and the cooling pipe, that is, the welded part,
There is no risk that the coolant or gaseous components such as hydrogen gas contained in the coolant will leak into the vacuum area.

Next, the detailed structure of the cover plate 5 will be explained.

The most important point required of the cover plate 5 in order to improve the cooling efficiency is how efficiently the heat flow caused by the impurity particles 9 incident on the surface of the cover plate 5 can be transmitted to the cooling plate 4. As mentioned above, since the diverter plate is used in a vacuum, the cover plate 5
The transfer of heat from the cooling plate 4 to the cooling plate 4 is performed by heat transfer and radiation, and there is no convection. Since heat transfer is more efficient than radiation, it is necessary to bring the cooling plate 4 and cover plate 5 into close contact as much as possible. For this reason, it is of course necessary to take care in machining, such as accurately machining the shape of the contact surface between the two, reducing the surface roughness, and choosing materials with high heat transfer efficiency, but in order to further increase heat transfer efficiency, For this reason, it is effective to configure the cover plate 5 as follows.

The cover plate 5 shown in FIG. 3 is made by cutting the inside of the cover plate 5 to create a space, placing a thin metal plate 12 to cover this space and sealing welding 13 around the periphery. A thin metal plate 12 is injected with a low melting point metal 14 such as lead.
The injection hole is blocked by allowing the injection hole to swell slightly. The cover plate 5 having such a structure is
By pressing and attaching the metal plate 12 to the cooling plate 4 so that it becomes a contact surface, it is possible to achieve the same effect as described above, and when the cover plate 5 is irradiated with impurity particles and heated, Since the low melting point metal 14 that is present melts, the thin metal plate 14
fits into the surface of the cooling plate 4, increasing the contact area between the two and improving heat transfer efficiency. In addition, when the flow of impurity particles 9 hits the surface of the cover plate 5, the particle density is low at the upper and lower ends of the cover plate 5, and the density is high at the center.
is heated so that the temperature is high at the center and low at the top and bottom ends, but the molten low-melting point metal 14 causes a convection phenomenon, and the heat is transferred from the center of the cover plate 5 where there is a large amount of heat input to the periphery where there is a small amount of heat input. Since the cover plate 5 moves rapidly, the heat load on the central portion of the cover plate 5 can be reduced.

The cover plate 5 shown in FIG. 4 applies the principle of a heat pipe. That is, a space is created by cutting the inside of the cover plate 5, a thin metal plate 12 is arranged to cover this space, and then a small amount of volatile liquid 15 is placed in this space, and this volatile liquid 15 is caused by capillary action. Metal flocculent 1 sucked up by
It is composed of 6 enclosed. Of course, by attaching the cover plate 5 having such a structure to the cooling plate 4, it is possible to obtain the same effect as in the first embodiment. The volatile liquid 15 sucked up is heated and vaporized to remove heat of vaporization. This vapor moves within the space by convection, heats the cooling plate 4 through the thin metal plate 12, and returns to liquid. When heated, the pressure in the space increases due to steam, so the metal plate 12 is pressed against the cooling plate 4, increasing the contact area between the two and improving heat transfer efficiency.

According to the divertor of the nuclear fusion device of the present invention described above, a plurality of diverter plates are arranged to surround the plasma in a vacuum container in which plasma is confined, and collide and remove impurity particles in the plasma. , a cooling plate connected to the cooling pipe and a cover plate removably provided on the plasma side of the cooling plate are integrated, and the cover plate has a space formed inside thereof, and A thin metal plate is arranged to cover the space, and since the space is formed by sealing a low-melting point metal or a volatile liquid and a metal flocculent, the diverter plate may be damaged by impurity particles. If the cover plate is damaged and needs to be replaced, it is as simple as removing the cover plate from the cooling plate and replacing it.There is no need to cut and reconnect the cooling pipes for replacement. The low melting point metal or volatile liquid and metal floccule sealed in the space inside the plate are heated and melted when impurity particles are incident on the diverter plate surface, and the mixture between the cover plate and the cooling plate is heated and melted. Since the contact area is increased and the heat flow caused by the impurity particles can be efficiently transferred, the cooling effect is improved, and this is very effective when used in the diverter of this type of fusion device.

[Brief explanation of the drawing]

FIG. 1 is a schematic partial cross-sectional view of a nuclear fusion device showing the arrangement of divertors according to an embodiment of the present invention, FIG. 2 is an exploded perspective view of a divertor plate according to an embodiment of the present invention, and FIG. FIG. 4 is a cross-sectional view showing an example of a specific structure of the cover plate of the invention, and FIG. 4 is a cross-sectional view showing another example of the cover plate. DESCRIPTION OF SYMBOLS 1...Plasma, 2...Blanket, 3...Diverter chamber, 4...Cooling plate, 5...Cover plate, 6...
Coolant circulation device, 7... Cooling piping, 8... Vacuum container,
9... Impurity particle, 10... Stay, 11... Bolt,
DESCRIPTION OF SYMBOLS 12...Metal plate, 13...Seal welding part, 14...Low melting point metal, 15...Volatile liquid, 16...Metal flocculent body.

Claims (1)

[Claims] 1. A vacuum vessel in which plasma is confined, a blanket disposed so as to surround the plasma within the vacuum vessel and forming a diverter chamber in a portion on the plasma side, and disposed within the diverter chamber of the blanket, a plurality of diverter plates that collide and remove impurity particles in the plasma, the diverter plates being connected to a coolant circulation device outside the vacuum vessel by a cooling pipe, each of the diverter plates comprising: It is constructed by integrating a cooling plate to which the cooling pipe is connected and a cover plate removably provided on the plasma side of the cooling plate, and the cover plate has a space formed inside thereof, and A diverter for a nuclear fusion device, characterized in that a thin metal plate is arranged to cover the space, and a low melting point metal or a volatile liquid and a metal flocculent are sealed in the space.