JPH0419593A - High frequency sending device for plasma heating - Google Patents

Abstract

PURPOSE:To facilitate the replacement of a protection member and to improve the operation rate by covering Faraday shields with a Faraday shield protection plate which has slits matching their gaps. CONSTITUTION:An antenna 10 stored in a jacket 9 radiates a high-frequency wave for heating to plasma 3 through its opening part. Then the Faraday shields 17 fitted to the opening part in a hurdle shape short-circuit electric field parts which are not necessary to heat the plasma 3. The device is provided with the shield protection plate 31 which has the slits 32 matching the gaps between the shields 17, is made of a high-fusion-point material, and passes high frequency waves while protecting the shields 17 from a thermal load from the plasma 3 and wear due to particles. One or a small number of protection plates 31 are used and not joined with the shields 17, and the four corners are clamped to a jacket 9 with bolts. Therefore, its replacement is easily performed in a short time through remote operation even in a vacuum container 2.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Field of Application) The present invention relates to a high-frequency emitting device for plasma heating, and particularly to a high-frequency emitting device for plasma heating that can easily replace a Faraday shield protection plate and improve the operating rate. Regarding a high frequency emitting device.

(Prior art) One method of heating plasma generated in a nuclear fusion reactor or nuclear fusion experimental device is a method that utilizes cyclotron motion (ion cyclotron resonance heating).

FIG. 7 is a configuration diagram of an ion cyclotron resonance heating device 1 for this purpose. Vacuum vessel 2 confines plasma 3. A plasma heating high frequency emitting device 6 supported by a pedestal 5 equipped with a moving mechanism 4 is inserted into the boat portion 2a of the vacuum container 2 via a bellows 7.

The high frequency emitting device 6 for plasma heating includes a jacket 9 having an opening 8 on the plasma 3 side, and an antenna 10 housed in the jacket 9 and emitting high frequency waves for plasma heating through the opening 8. A transmission line 11 for transmitting is connected. A transmission line 11 is extended from the plasma heating high frequency emitting device 6 through the pedestal 5 and connected to a source oscillator 13 via an amplifier 12.

Furthermore, a switch 15 that can be switched and connected to the dummy load 14 and an impedance matching device 16 are connected to the transmission line 11 between the amplifier 12 and the plasma heating high frequency emitting device 6 from the amplifier 12 side.

A stretchable portion 11a is provided in a portion of the transmission line 11 that is close to the pedestal 5.

Ion cyclotron resonance heating device 1 having such a configuration
, the high frequency emitted from the source oscillator 13 is amplified by the amplifier 12, conducts through the transmission line 11, passes through the switch 15 and the impedance matching device 16, and is transmitted to the high frequency emitting device 6 for plasma heating. It reaches the antenna 10. Then, high frequency waves are emitted from the antenna 10 toward the plasma 3.

If it is not necessary to send high frequency waves to the plasma heating high frequency emitting device 6, the high frequency waves are sent from the switch 15 to the dummy load 14. The impedance matching device 16 also improves the efficiency of high frequency power.

Note that when the moving mechanism 4 of the pedestal 5 is operated, the high-frequency emitting device 6 for plasma heating expands and contracts the bellows 7.
The insertion position within the vacuum container 2 can be changed, and in this case, the transmission line 11 can follow the movement of the plasma heating high-frequency emitting device 6 thanks to the expansion/contraction section 11a.

FIG. 8 is a perspective view of the opening 8 of the high-frequency emitting device 6 for plasma heating, and FIG. 9 is a view taken along the line IX--IX in FIG. 7. The same reference numerals are given to the parts corresponding to those in Fig. 7.

A plurality of rod-shaped Faraday shields 17 are attached to the opening (end) 8 of the jacket 9 of the high-frequency emitting device 6 for plasma heating at the end of the vacuum vessel boat section 2a, covering the antenna 10 in the form of a drainboard. The Faraday shield 17 protects the surface of the antenna 100 from heat load from the plasma 3 and wear due to particles, and short-circuits electric field components unnecessary for heating the plasma.

FIG. 10 is a sectional view taken along the line X--X in FIG. 7. The same reference numerals are given to the parts corresponding to those in FIGS. 7 to 9.

When the plasma heating high frequency emitting device 6 is in operation, the Faraday shield 17 is moved via the moving mechanism 4 to a position where it forms the same spherical surface as the wall surface 2b surrounding the plasma 3 of the vacuum container 2. Therefore, while the plasma 3 is being generated, the Faraday shield 17 is exposed to the same conditions as the wall surface 2b of the vacuum vessel 2, receives the same heat load from the plasma 3 as the wall surface 2b, and is also subject to nuclear heat generation due to gamma rays or neutron beams. arise.

Therefore, as shown in FIG. 11, which is a cross-sectional view taken along the line XI-XI in FIG. Usually, a cooling channel 18 is formed, and a cooling medium (for example, water) 19 is passed through the cooling channel 18 to reduce the heat load or heat generation of the Faraday shield 17 . Note that the reference numeral 20 is a cooling water supply/discharge pipe through which cooling water flows to reduce heat generation on the surface of the antenna 5.

As also shown in FIG. 11, recently a Faraday shield protective film 21 molded from a high melting point material such as graphite or carbon-based composite material is bonded to the plasma 3 side of each Faraday shield 17 by brazing or the like. This Faraday shield protective film 21 plays a role of actively protecting the Faraday shield 17 from heat load of the plasma 3 and wear and tear caused by particles from the plasma 3, in addition to the cooling channel 18. Figure 12 shows the Faraday shield protective film 2.
1 is a perspective view of one of the parts. Portions corresponding to those in FIG. 11 are given the same reference numerals.

(Problems to be Solved by the Invention) Incidentally, the Faraday shield protective film 21 is also worn out by particles from the plasma 3 if the device is operated for a long period of time. Particularly in the case of a nuclear fusion reactor, the strength of the Faraday shield protective film 21 decreases faster than usual because it is exposed to neutrons.

Therefore, the Faraday shield protective film 21 needs to be replaced at regular intervals. In this case, remote work is assumed in nuclear fusion reactors, etc., but even if you try to replace the Faraday shield protective film 21 together with the Faraday shield 17, the Faraday shield 17 is firmly attached to the jacket 9, so it is difficult to replace the Faraday shield protective film 21. It is difficult to replace the heating high-frequency emitting device 6 while it is housed in the boat portion 2a of the vacuum container 2.

Therefore, a method is currently being considered in which only the Faraday shield protective film 21 is replaced while the Faraday shield 17 remains attached to the jacket 9. However, even in that case, the number of Faraday shield protective films 21 is large and the size is about several tens of millimeters at most. It is inevitable that the work will be difficult when brazing inside.

For this reason, the replacement work takes a long time, and there was concern that the operating rate of the plasma heating high-frequency emitting device would decrease.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a high-frequency emitting device for plasma heating in which members related to the protection of the Faraday shield can be easily replaced and the operating rate can be improved.

[Structure of the invention]

(Means for Solving the Problems) In order to solve the above problems, the present invention includes a jacket having an opening on the plasma side;
an antenna that emits high frequency waves for plasma heating through the opening; a plurality of Faraday shields that are attached to the opening of the jacket in a slatted manner to short-circuit electric field components unnecessary for heating the plasma; and between each of the Faraday shields. and a Faraday shield protection plate that is attached to the jacket and allows high frequency waves to pass through while protecting the Faraday shield from heat load from the plasma and wear and tear caused by particles. The purpose is to provide.

(Function) In the high-frequency emitting device for plasma heating of the present invention, the Faraday shield is covered with a Faraday shield protection plate having slits that match the gaps between the Faraday shields. Regardless of the number of Faraday shields, it is sufficient to install one or a very small number of Faraday shield protection plates. This Faraday shield protection plate does not need to be joined to the Faraday shield, and can be attached to the jacket by bolting or the like. Therefore, this Faraday shield protection plate can be replaced extremely easily even if it is replaced by remote control.

(Example) The present invention will be described in detail below with reference to FIGS. 1 to 6.

FIG. 1 is a cutaway perspective view of a plasma heating high frequency emitting device 3o according to an embodiment of the present invention, and FIG. 2 is a Faraday shield protection plate 3 of this plasma heating high frequency emitting device 3o.
FIG. 3 is a front view seen from one direction, and FIG. 3 is a sectional view taken along the line ■--■ in FIG. In these figures, Figures 7 to 1
Portions corresponding to those in FIG. 2 are given the same reference numerals and detailed explanations will be omitted.

In the Faraday shield protection plate 31 of this embodiment,
A Faraday shield 17 is attached in the shape of a drainboard to the plasma 3 side end (opening) of the jacket 9 to protect the antenna 10 housed in the jacket 9. Then, each Faraday shield 17 is brought into contact with one Faraday shield protection plate 31 having a slit 32 of a size that exactly matches the gap between each Faraday shield 17. antenna 1
The high frequency waves emitted from the plasma 3 pass through the slit 32 and reach the plasma 3.

FIG. 4 is a perspective view of the Faraday shield protection plate 31, and FIG. 5 is a sectional view taken along the line V--V in FIG. 4.

Reference numeral 33 indicates a bolt hole in the Faraday shield protection plate 31. The contact portion 31a of the Faraday shield protection plate 31 with the Faraday shield 17 is processed into a bowl shape in accordance with the plasma 3 side profile of the cylindrical Faraday shield 17. Therefore, the plasma 3 side of each Faraday shield 17 is covered with the Faraday shield protection plate 31,
It will not be exposed at all.

This Faraday shield protection plate 31 is fitted with a bolt 3 through a bolt hole 33 in an opening 8 on the plasma 3 side of the jacket 9.
Attached by 4. The Faraday shield protection plate 31 of this embodiment is made of a high melting point material such as graphite or a carbon-based composite material. Therefore, this Faraday shield protection plate 31 completely protects each Faraday shield 17 from heat load from the plasma 3 and wear and tear due to particles emitted from the plasma 3, and the Faraday shield 17 protects the antenna 10 from heat and damage. It also serves as a short-circuit for unnecessary electric field components and can be left open for a long time.

Note that the reference numeral 35 indicates the transmission line 11 connected to the antenna 10.
It is a coaxial tube containing.

Now, if the Faraday shield protection plate 31 used in this embodiment is operated for a long period of time in the high frequency emitting device 30 for plasma heating, the Faraday shield protection plate 31 will be worn out by particles emitted from the plasma 3, and its strength will be reduced by neutrons from the plasma 3. At this time, the Faraday shield protection plate 31 must be replaced, but there is only one Faraday shield protection plate 31, and it is not connected to each Faraday shield 17, but is simply bolted to the jacket 9 at the four corners. It is. Therefore, the Faraday shield protection plate 31 can be easily replaced in a short time by simply attaching and detaching the bolts 34 by remote control even if the plasma heating high-frequency emitting device 30 is inside the vacuum vessel 2. , the operating rate of the high-frequency emitting device 30 for plasma heating can be significantly increased.

FIG. 6 is a perspective view of a high frequency emitting device 36 for plasma heating according to a second embodiment of the present invention. The same reference numerals are given to the parts corresponding to those in the first embodiment, and the explanation thereof will be omitted.

The Faraday shield protection plate 37 used in the plasma heating high frequency emitting device 36 of this embodiment consists of three sheets, each of which is attached to an end of the jacket 9 with a bolt 34. Note that the number of Faraday shield protection plates is not limited to the number in this embodiment, but in consideration of ease of handling, a smaller number is preferable. Furthermore, the means for attaching the jacket of the Faraday shield protection plate is not limited to bolts, as long as it is easy to attach and remove.

If the Faraday shield protection plate is divided appropriately as in this embodiment, even if the plasma heating high frequency emitting device 36 becomes larger, each Faraday shield protection plate 37 can be kept small in both weight and volume, and it is possible to keep the Faraday shield protection plate 37 small in both weight and volume. It becomes possible to keep the weight within the allowable handling weight of the remote working device.

〔Effect of the invention〕

As explained above, according to the present invention, the Faraday shield protection plate has one Faraday shield protection plate regardless of the number of Faraday shields.
It is only necessary to install one or a very small number of them, and replacement work can be easily performed by removing bolts, etc. Therefore, the high frequency emitting device for plasma heating of the present invention can shorten the time required to replace the Faraday shield protection plate, increase the operating rate, and improve economic efficiency.

[Brief explanation of the drawing]

1 and 2 are a perspective view and a plan view, respectively, of a high-frequency emitting device for plasma heating according to a first embodiment of the present invention, FIG. 3 is a sectional view taken along line mm in FIG. 2, and FIG. A perspective view of the Faraday shield protection plate shown in Figure 1, and Figure 5 is a perspective view of the Faraday shield protection plate shown in Figure 4.
-V line sectional view, FIG. 6 is a perspective view of a high-frequency emitting device for plasma heating according to the second embodiment of the present invention, FIG. 7 is a configuration diagram of an ion cyclotron resonance heating device, and FIG. 8 is a conventional plasma heating device. A perspective view of the heating high-frequency emitting device, FIGS. 9 and 10 are sectional views taken along lines IX-IX and X-X in FIG. 7, respectively, and FIG.
The I-line sectional view and FIG. 12 are perspective views of a conventional Faraday shield protection plate. 3... Plasma, 9... Jacket, 1o... Antenna, 17... Faraday shield, 31... Faraday shield protection plate, 32... Slit. J Figure 3 Figure 4 Figure 5 Figure 6 Figure CJI Figure 7 Figure 8 Figure 11 Figure 12

Claims (1)

[Claims] a jacket with an opening on the plasma side; an antenna housed in the jacket that emits high-frequency waves for heating the plasma through the opening; It has a plurality of Faraday shields that short-circuit the components and slits that match the gaps between the Faraday shields, and is attached to the jacket to protect the Faraday shields from heat load from plasma and wear due to particles while transmitting high frequencies. A high frequency emitting device for plasma heating, which is equipped with a Faraday shield protection plate that allows the waves to pass through.