JPH08338889A - Diamond clad device and method for fusion reactor first wall - Google Patents

Abstract

PURPOSE: To enable directly cladding diamond thin film with large area, few impurity and good crystallinity. CONSTITUTION: Provided are a reaction vessel 16 of which one end is opened and at the other end, seal plate 20 is placed to produce ECR(electron cyclotron resonance) plasma 23 in the front of the first wall, a gas introduction inlet 17 projected from the open end of the reaction vessel 16 to supply the reaction vessel with reaction gas 18, a magnetic field generation means 22 arranged around the reaction vessel 16 and a waveguide 19 fixed to the other end of the reaction vessel 16 to introduce microwave 21.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a diamond coating device and a diamond coating method for a first wall of a fusion reactor.

[0002]

2. Description of the Related Art Generally, the first wall of a fusion reactor is subjected to a high heat load due to plasma and is also exposed to a high temperature, so that it has a high melting point and a high heat conduction. A carbon material which is a low atomic material that cannot be lowered is used, and a diamond coating made of carbon is one of the carbon materials. Further, when the coating layer is damaged, a plasma gun that can easily repair the first wall is brought into the furnace, and repair in the vacuum container is under study.

An example of a conventional diamond coating device for the first wall of a fusion reactor is disclosed in Japanese Patent Laid-Open No. 4-353794. This diamond coating device is shown in FIG.
As shown in FIG. 3, the cooling groove 2 is formed in the structural material 1, the refractory alloy layer 3 is covered, and the diamond coating layer 5 is covered by the plasma jet 4 on the surface of the refractory alloy layer 3.

Here, the plasma jet 4 is one in which methane and hydrogen as the reaction gas 9 are heated to a high temperature and discharged together with the argon plasma 8 generated between the high voltage electrodes 7 in the plasma gun 6. Is radiated onto the surface of the high melting point alloy layer 3 to rapidly cool the gas, whereby diamond is deposited and the diamond coating layer 5 is formed.

[0005]

By the way, in the conventional diamond coating apparatus as described above, the coating area at one place is small and the cross-sectional area of the plasma jet 4 is about the same.
The diameter of the plasma jet 4 is 4 to 8 mm at 1 atm.

Further, since the argon plasma 8 is used, there is a problem that the argon gas taken into the produced diamond thin film is mixed into the core plasma as an impurity.

Further, since the spatial existence of plasma in the plasma jet 4 is local, and the spatial distribution and the plasma temperature change rapidly, the diamond coating layer 5 produced by the plasma jet 4 has a crystalline property. Unfortunately, substances other than diamond, such as amorphous carbon, are also generated together with diamond, and there is a problem that the thermal conductivity deteriorates.

Further, when the diamond coating layer 5 is generated by the plasma jet 4, the surface of the coating layer is exposed to the high temperature of thermal plasma, so that it is impossible to directly coat the structural material such as SUS which is a metal material. As described above, it is necessary to coat the refractory alloy layer 3 and then diamond coating and cool the structural material.

The present invention has been made in consideration of the above circumstances, and a diamond thin film having a large area, a small amount of impurities and good crystallinity can be directly coated on a metal material at a low temperature which does not require cooling. An object of the present invention is to provide a diamond coating device and a diamond coating method for a first wall of a fusion reactor.

[0010]

In order to solve the above-mentioned problems, the first aspect of the present invention is that one end is an open end and a hermetically sealing plate is attached to the other end to generate ECR plasma in front of the first wall. To the reaction container, a gas inlet projecting from the open end of the reaction container to supply a reaction gas to the reaction container, a magnetic field generating means arranged on the outer periphery of the reaction container, and the other end of the reaction container. And a waveguide for introducing microwaves.

A second aspect of the present invention is characterized in that the reaction gas according to the first aspect comprises hydrogen and a carbon compound.

A third aspect of the invention is characterized in that the magnetic field generating means according to the first aspect is one of a magnetic field coil and a permanent magnet.

A fourth aspect of the present invention is characterized in that the magnetic field generating means according to the first or third aspect is configured to be movable so as to form a predetermined angle with respect to the axial direction of the reaction container.

A fifth aspect is characterized in that a voltage applying means is connected to the reaction vessel according to the first aspect.

According to a sixth aspect of the present invention, the reaction gas is supplied to the reaction vessel, the microwave is introduced from the microwave source using the waveguide, and the magnetic field generating means disposed on the outer periphery of the reaction vessel is excited to generate the reaction gas, A fusion reactor in which ECR plasma is generated in front of the first wall by the interaction of the microwave and the magnetic field, and a metal material is coated with diamond. Is characterized by exciting a poloidal coil arranged outside the vacuum container.

[0016]

In the first aspect of the present invention having the above structure, electron cyclotron resonance (hereinafter referred to as ECR).
A plasma-generated coating (generally known as an ECR plasma CVD method) produces several hundreds of coatings in one place.
Since a coating of about cm ² is possible, the ECR in front of the first wall
A large area can be coated at once by generating plasma.

As conditions for producing a diamond thin film having few impurities and good crystallinity, there are temperature conditions of the coating surface, plasma density conditions, etc., and the control of the coating surface temperature and the plasma density by changing the microwave input. By performing the above, it is possible to form a diamond coating layer having few impurities and good crystallinity.

Furthermore, since diamond coating can be performed at a coating surface temperature of 500 to 800 ° C., it is possible to form a diamond coating layer directly on the surface of a structural material without the need for cooling or coating with a high melting point material.

According to the second aspect of the present invention, by using a gas containing only a carbon compound containing carbon, which is a diamond-forming element, and hydrogen, which is the same as the gas used for core plasma generation, without using argon gas, the residual The problem of gas and impurities in the film can be avoided.

According to a third aspect of the present invention, the magnetic field generating means is either a magnetic field coil or a permanent magnet. Particularly, in the case of a permanent magnet, a current drive mechanism for exciting the coil is not required, and the apparatus is lightweight and simple. Can be realized.

According to the present invention, the magnetic field generating means is configured to be movable so as to form a predetermined angle with respect to the axial direction of the reaction vessel, so that the coating position can be changed without moving the main body. The covered area at one location becomes large.

In the present invention, the voltage applying means is connected to the reaction vessel, so that a negative potential is applied to the reaction vessel during the formation of the diamond film, thereby accelerating the electrons toward the coating surface and causing the electrons on the coating surface. Can increase the rate of diamond film formation.

According to the present invention, by exciting the poloidal coil arranged outside the vacuum vessel of the fusion reactor together with the magnetic field generating means, the exciting magnetic field generated by the magnetic field generating means can be reduced, and the magnetic field generating means can be made compact. The weight of the device can be reduced.

[0024]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a vertical sectional view showing a first embodiment of a diamond coating device for a first wall of a fusion reactor according to the present invention, and FIG. 2 is an outline of repairing the first wall of the fusion reactor according to the first embodiment. It is sectional drawing shown.

As shown in FIG. 2, the vacuum vessel 10 in the fusion reactor is provided with a repair port 11, and a diamond coating device 13 is introduced from the repair port 11 by a manipulator 12 to be a metallic material SUS. Diamond coating layer 1 on the surface of structural material 14 (shown in FIG. 1) such as
5 is formed.

As shown in FIG. 1, the diamond coating device 13 has a gas inlet 17 projecting from the open end of one end of the reaction vessel 16, and methane and hydrogen as reaction gases 18 are supplied from the gas inlet 17 to the reaction vessel. 16 is supplied to the front of the open end. In addition, a waveguide 19 from a microwave source (not shown)
End plate 16a fixed to the other end of the reaction vessel 16 using
The microwave 21 of 2.45 GHz is introduced into the reaction container 16 through the airtight sealing plate 20 attached to the. A magnetic field coil 22 as a magnetic field generating means is arranged on the outer peripheral side of the reaction vessel 16 and excites the magnetic field coil 22. Therefore, the ECR plasma 23 is generated at the position of the magnetic field of 875 GHz by the interaction of the magnetic field by the reaction gas 18, the microwave 21, and the magnetic field coil 22 as described above.

The diamond coating device 13 shown in FIG. 2 is used so that the ECR plasma 23 is generated immediately before the structural material 14.
The position of is adjusted by the manipulator 12. Then, active C particles and H in the generated ECR plasma 23
Particles and electrons react on the surface of the structural material 14 and are generated by the diamond coating device 13.

Next, the operation of this embodiment will be described.

The production range of the plasma 23 is defined by the reaction container 16
Since it is about the same as the opening cross-sectional area of
A coating of about 00 cm ² is possible, and a large area can be coated at once. That is, since the coating by ECR plasma generation (generally known as the ECR plasma CVD method) can cover several hundred cm ² with one coating, the ECR plasma 23 is generated in front of the first wall. As a result, it is possible to cover a large area at once.

As conditions for producing a diamond thin film with few impurities and good crystallinity, there are temperature conditions of the coating surface, plasma density conditions, etc. By performing the control, it is possible to form the diamond coating layer 15 having less impurities and good crystallinity.

Furthermore, since diamond coating can be performed at a coating surface temperature of 500 to 800 ° C., the diamond coating layer 15 can be directly formed on the surface of the structural material 14 without the need for cooling or coating with a high melting point material.

Furthermore, without using argon gas, hydrocarbons such as methane containing carbon as a diamond-forming element as reaction gas, carbon compounds such as carbon monoxide and carbon dioxide, and gas used for core plasma generation. By using a gas composed of only hydrogen, which is the same as the above, the problems of residual gas and impurities in the film can be avoided.

FIG. 3 shows a second embodiment of the diamond coating apparatus for the first wall of the fusion reactor according to the present invention. In the first embodiment, the diamond coating device 13 was operated in order to generate the ECR plasma 23 immediately before the structural material 14, but in the present embodiment, the distance from the magnetic field coil 22 to the magnetic field of 875 GHz is the exciting current. By changing the exciting current, the ECR plasma 2 can be changed.
The position of the magnetic field of 875 GHz generated by 3 and the reaction vessel 16
It controls the distance of the open end of the.

Next, the operation of this embodiment will be described.

By changing the current of the magnetic field coil 22 without moving the entire diamond coating device 13, the magnetic field can be changed and the distance between the position where the ECR plasma 23 is generated and the open end of the reaction vessel 16 can be changed. It will be possible. As a result, the ECR plasma 2 is formed immediately before the structural material 14.
It is not necessary to perform strict adjustment by the manipulator 12 for generating 3. In addition, EC to the recessed position
It is also possible to generate R plasma 23 and perform coating.

FIG. 4 is a vertical sectional view showing a third embodiment of the diamond coating apparatus for the first wall of the fusion reactor according to the present invention.
The same parts as those in the first embodiment will be described with the same reference numerals. The same applies to the following embodiments. The first
In the embodiment, the magnetic field coil 22 is used for generating the magnetic field, but in the present embodiment, the permanent magnet 25 as the magnetic field generating means is provided for generating the magnetic field.

As a result, a current driving mechanism for exciting the magnetic field coil is not required, and the diamond coating device 13 can be made light and simple. Other configurations and operations are similar to those of the first embodiment. Also, in the following embodiments, only the structure and operation different from those of the first embodiment will be described.

FIG. 5 is a longitudinal sectional view showing a fourth embodiment of the diamond coating apparatus for the first wall of the fusion reactor according to the present invention.
In the present embodiment, in the diamond coating device 13 of the third embodiment, an auxiliary coil 26 is arranged adjacent to the permanent magnet 25, and a constant magnetic field is constantly excited by the permanent magnet 25. By changing the coil current of 26, the distance between the ECR plasma 23 and the open end of the reaction vessel 16 is controlled.

This eliminates the need for strict adjustment by the manipulator 12 to generate the ECR plasma 23 immediately before the structural material 14. In addition, it is possible to generate the ECR plasma 23 in the recessed position and perform coating. Further, the magnetic field coil is based on the beam of the second embodiment,
A small size with a small exciting current is sufficient.

FIG. 6 is a longitudinal sectional view showing a fifth embodiment of the diamond coating apparatus for the first wall of the fusion reactor according to the present invention.
In this embodiment, the diamond coating device 1 of the first embodiment is used.
3, the magnetic field coil 22 is driven by the coil driving mechanism 27.
Is movable with a predetermined angle to the axial direction of the reaction vessel 16, and the generation position of the ECR plasma 23 can be changed vertically and horizontally when the surface of the structural material 14 is viewed from the axial direction of the vessel. It is configured to be possible.

As a result, the diamond coating device 13 can be changed vertically and horizontally without moving the device.
The covered area at one location becomes large.

FIG. 7 is a vertical sectional view showing a sixth embodiment of the diamond coating apparatus for the first wall of the fusion reactor according to the present invention.
In this embodiment, in the diamond coating apparatus of the first to fifth embodiments, the stabilizing power supply 2 is provided outside the reaction vessel 16.
Install 8. A voltage can be applied from the stabilized power supply 28.

As a result, it is possible to apply a negative potential to the reaction vessel 16 during the formation of the diamond film, accelerate the electrons by the electric field 29, and give an impact to the coating surface of the structural material 14 with the electrons. As a result, the production rate of the diamond coating layer 15 can be increased.

FIG. 8 is a longitudinal sectional view showing an embodiment of the method for coating diamond on the first wall of a fusion reactor according to the present invention. In the first to fifth embodiments, the reaction container 1 is used to generate a magnetic field.
Although the magnetic field coil 22 or the permanent magnet 25 is arranged on the outer peripheral side of 6, the poloidal coil 30 arranged on the outer periphery of the vacuum container 10 is excited together with the magnetic field coil 22 in this embodiment.

In this embodiment, as in the case of the first embodiment, the reaction gas 16 is supplied to the reaction vessel 16 and the microwave 21 is introduced from the microwave source using the waveguide 19 and the reaction vessel 16 is used. The magnetic field coil 22 arranged on the outer circumference is excited to generate the ECR plasma 23 in front of the first wall by the interaction of the reaction gas 18, the microwave 21 and the magnetic field,
The structural material 14 is coated with diamond.

Next, the operation of this embodiment will be described.

In the present embodiment, the magnetic field generated by the poloidal coil 30 is superposed to generate 875 GHz.
The coil current of the magnetic field coil 22 is adjusted so that the ECR plasma 23 is generated immediately before the structural material 14. As a result, the magnetic field excited by the magnetic field coil 22 is narrowed, the magnetic field coil 22 can be downsized, and the weight of the diamond coating device 13 can be reduced.

[0049]

As described above, according to the first aspect of the present invention.
According to the above, a reaction container that has an open end at one end and an airtight sealing plate is attached to the other end to generate ECR plasma in front of the first wall, and a reaction gas that projects from the open end of the reaction container and is supplied to the reaction container By providing a gas introduction port, a magnetic field generating means arranged on the outer periphery of the reaction container, and a waveguide for introducing a microwave attached to the other end of the reaction container, a large area can be obtained. The diamond thin film having few impurities and good crystallinity can be directly coated on the metal material at a low temperature that does not require cooling.

According to the second aspect of the present invention, by using a carbon compound containing carbon, which is a diamond forming element, and a gas composed of only hydrogen, which is the same as the gas used for core plasma generation, without using argon gas, Problems of residual gas and impurities in the film can be avoided.

According to the third aspect, the magnetic field generating means is either one of the magnetic field coil and the permanent magnet. Especially, in the case of the permanent magnet, the current driving mechanism for exciting the coil is not required, and the weight of the device is reduced. It can be simplified.

According to the fourth aspect, the magnetic field generating means is configured to be movable so as to form a predetermined angle with respect to the axial direction of the reaction container, so that the coating position can be changed without moving the main body. The coverage area at one location becomes large.

According to the fifth aspect, by connecting the voltage applying means to the reaction vessel, a negative potential is applied to the reaction vessel during the formation of the diamond film, thereby accelerating the electrons toward the coated surface and causing the coated surface to move. Electron bombardment can be applied to increase the rate of diamond coating formation.

According to the sixth aspect, by exciting the poloidal coil arranged outside the vacuum vessel of the fusion reactor together with the magnetic field generating means, the exciting magnetic field by the magnetic field generating means can be reduced, and the magnetic field generating means can be reduced. The weight of the device can be reduced by downsizing.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view showing a first embodiment of a diamond coating device for a first wall of a fusion reactor according to the present invention.

FIG. 2 is a sectional view showing an outline of repairing the first wall of the fusion reactor according to the first embodiment.

FIG. 3 is a diagram showing a relationship between a coil current and a generated magnetic field in the second embodiment of the diamond coating device for the first wall of the fusion reactor according to the present invention.

FIG. 4 is a vertical sectional view showing a third embodiment of the diamond coating device for the first wall of the fusion reactor according to the present invention.

FIG. 5 is a longitudinal sectional view showing a fourth embodiment of the diamond coating device for the first wall of the fusion reactor according to the present invention.

FIG. 6 is a vertical sectional view showing a fifth embodiment of the diamond coating device for the first wall of the fusion reactor according to the present invention.

FIG. 7 is a vertical cross-sectional view showing a sixth embodiment of the diamond coating device for the first wall of the fusion reactor according to the present invention.

FIG. 8 is a vertical sectional view showing an embodiment of a method for coating diamond on the first wall of the fusion reactor according to the present invention.

FIG. 9 is a longitudinal sectional view showing an example of a conventional diamond coating device for the first wall of a fusion reactor.

[Explanation of symbols]

 10 vacuum container 11 repair port 12 manipulator 13 diamond coating device 14 structural material 15 diamond coating layer 16 reaction vessel 16a end plate 17 gas inlet port 18 reaction gas 19 waveguide 20 airtight sealing plate 21 microwave 22 magnetic field coil ( Magnetic field generation means) 23 ECR plasma 25 Permanent magnet (magnetic field generation means) 26 Auxiliary coil 27 Coil drive mechanism 28 Stabilized power supply 29 Electric field 30 Poloidal coil

Claims (6)

[Claims] 1. A reaction vessel having an open end at one end and an airtight sealing plate attached to the other end to generate plasma in front of the first wall, and a reaction gas projecting from the open end of the reaction vessel to supply a reaction gas to the reaction vessel. A gas introduction port, a magnetic field generating means arranged on the outer periphery of the reaction vessel, and a waveguide for introducing microwaves attached to the other end of the reaction vessel. Diamond coating device for the first wall of the fusion furnace. 2. The diamond coating device for the first wall of the nuclear fusion reactor according to claim 1, wherein the reaction gas comprises hydrogen and a carbon compound. 3. The diamond coating device for the first wall of the nuclear fusion reactor according to claim 1, wherein the magnetic field generating means is one of a magnetic field coil and a permanent magnet. 4. The diamond coating on the first wall of the nuclear fusion reactor according to claim 1, wherein the magnetic field generating means is configured to be movable at a predetermined angle with respect to the axial direction of the reaction vessel. apparatus. 5. The diamond coating device for the first wall of the fusion reactor according to claim 1, wherein a voltage applying means is connected to the reaction vessel. 6. A reaction gas is supplied to a reaction vessel, a microwave is introduced from a microwave source using a waveguide, and a magnetic field generating means disposed on the outer periphery of the reaction vessel is excited to generate the reaction gas, the microwave. A method for coating a diamond on a first wall of a fusion reactor in which plasma is generated in front of the first wall by interaction of a magnetic field and diamond to coat a metal material with diamond. A diamond coating method for a first wall of a fusion reactor, comprising exciting a poloidal coil arranged outside.