JPS63193497A - Faraday shield - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to a Faraday shield installed in a high-frequency heating device that additionally heats the plasma of a nuclear fusion device, and particularly relates to a Faraday shield installed in a high-frequency heating device for additionally heating plasma in a nuclear fusion device. This invention relates to a Faraday shield for a heating device.

(Prior art) For plasma heating in nuclear fusion devices, Soyur heating is used to heat the plasma by passing an electric current through it, and in addition to this, neutral particle injection heating, high frequency heating, etc. are used as second-stage heating methods. ing.

The above-mentioned high-frequency heating method is a method of increasing the temperature of the plasma by absorbing high-frequency electromagnetic energy into the plasma generated in a vacuum container. One of them is the ion cyclotron frequency band (hereinafter abbreviated as ICRF).
There is a high frequency heating device.

As shown in Figure 4, the ICRF high-frequency heating device includes a high-frequency oscillator 1 that generates and amplifies a high-output single-frequency wave in the hundreds of MHz band.
, a coaxial cable type high frequency transmission system 3 that transmits the high frequency output generated from this high frequency oscillator 1 to the tokamak device 2, and a high frequency transmission system 3 connected to this transmission system 3 that generates Takaoka electric power in the vacuum vessel of the tokamak device 2. and a coupling system 5 corresponding to an antenna that emits the plasma 4.

The coupling system 5 includes a loop antenna system and a T-type SUP 4-wave tube system depending on the compatibility with the tokamak device 2, but here the T-SUP 4-wave tube system is targeted.

This T-type drop waveguide type coupling system 5 includes a vacuum vessel 5a.
A waveguide 6 is housed inside and directly connected to the main body of the tokamak device 2.

Therefore, the waveguide 6 is placed under harsh environments such as high X9 and high heat load. Further, as the tokamak device 2 becomes larger, the waveguide 6 is operated for a long period of time, and is required to meet more severe environmental conditions. In addition to the above-mentioned requirements, the magnetic field created by the high-frequency current guided by the waveguide 8 tube 6 is passed to the outside, but the waveguide 6t is electrostatically shielded and high-energy particles from the plasma 4 are guided. The waveguide 6 is used as a means to suppress intrusion into the inside of the tube 6 as much as possible.
A Faraday shield 7 is attached to the tip.

FIG. 5 shows a conventional Faraday shield, in which a sagging inner shield plate 8 and an outer shield plate 9 are fixed by bolts 10, for example, so as to cover the end face of the waveguide 6. The shield plate 8.9 is constructed so as to wrap around the opening of the sag so that it does not seem to get dusty. The inner shield plate 8 and the outer shield plate 9 are arranged with a predetermined gap so that the magnetic field generated by the high-frequency current passes through to the plasma 4 side, and both ends of the U-shape are attached to the sides of the waveguide 6. In the 7 Allade shield configured as described above, inertial cooling is realized in which the heat irradiated from the plasma 4 is absorbed by the heat capacity of the shield plates 8 and 9, and cooled by heat conduction to the waveguide 1g6. Therefore, the requirements are met when the tokamak device operates for short periods of time and has long pulse intervals, such as a small experimental-scale tokamak device, but a cauldron tokamak device does not meet the requirements, especially regarding cooling. , rarely available.

That is, the reason will be described below.

Bolts 1 are attached to the sides of the waveguide 6 at both ends of the shield plates 8 and 9.
Since it is fixed at 0, it thermally expands due to the irradiation heat from the plasma 4 during operation and is subjected to edge bending stress, which also poses a problem in terms of life.

- As the tokamak device 2 becomes larger, the irradiation heat flow bed from the plasma 4 also becomes narrower 9, and a large amount of irradiation heat is generated not only in the radial direction of the plasma but also in the circumferential direction. In particular, in the circumferential direction, if the main body of the tokamak device 2 is not provided with a heat receiving protection plate for the high-frequency heating device, the heat flux is several times that in the radial direction, and there is a problem in heat resistance.

Furthermore, as the size of the tokamak device 112 increases, its operation time becomes long/4' luth and almost continuous. It was unusable.

(Problems to be Solved by the Invention) In this way, in the conventional technology, the irradiated heat from the plasma is cooled by an inertial cooling method that uses only heat conduction. In addition, there was a problem with heat resistance during almost continuous long-term operation.

The present invention was made based on the above circumstances, and its object is to provide a Faraday shield that can withstand high heat flux and can be used for long-term operation.

[Structure of the Invention] (Means for Solving the Problems) In order to achieve the above object, the Faraday shield according to the present invention includes a pair of jackets attached to both sides of the tip of a waveguide, and nine connected to each jacket. It is characterized by comprising a number of finned pipes through which the refrigerant passes, and a guard limiter attached to the side opposite to the waveguide of the jacket, and in which the refrigerant is allowed to pass through the jacket and the finned pipes.

(Function) In this way, in the present invention, by passing a refrigerant through the jacket and the finned pipe, cooling can be performed separately in the radial direction where the heat flux is relatively small and the circumferential direction where the heat flux is large. It becomes possible to withstand bundles and long-term operation.

(Example) Below, the Faraday shield according to the present invention is shown in FIGS. 1 to 3.
Description will be made according to an embodiment shown in the figure. Note that from FIG. 1 onward, the same members as those in FIG. 5 are designated by the same reference numerals, and detailed explanation thereof will be omitted.

In FIG. 1, ;roa, 1! Ob is a pair of jackets, and the jacket 20h and the jacket 20b are connected by a finned groove f21, and are attached to the waveguide 6 as an elastic body with a hexagonal bolt 23 via a wave spring 22. ing. Note that 27 is a presser plate.

A guard limiter 24 made of a high melting point material such as molybdenum is fixed to the opposite side of the waveguide of the jackets 20th and 20b with silver brazing or the like. This guard limiter-24
The tip is divided into two pieces, an outer plate 24& and an inner plate 24b, and each side plate 24h and 24b is provided so as to be wrapped by a slint 24c.

Further, a supply motherboard 25 for supplying refrigerant from an externally provided refrigerant supply device (not shown) is connected to the upper part of the jacket 2θa, and the jacket 20b is connected to the exhaust i4 iso2
6 is connected.

According to the Faraday shield of this embodiment configured as described above, the refrigerant supplied from the external refrigerant supply device (not shown) is supplied with
, the finned refrigerant tube 2 passes through the jacket 20b and returns to the refrigerant supply point I& at the discharge tube 26.

In this way, the refrigerant can be circulated during operation, so
The radial heat flux from the plasma is finned pi f21
The heat flux in the circumferential direction can be removed by the jackets 20 & 20b via the guard limiter 24t, thereby suppressing the heat intrusion into the waveguide 6 as much as possible.

On the other hand, the high frequency magnetic field is the fin 21m of the finned pie f21.
The plasma provided in the gap 21b and the guard limiter 24 can be dissipated from J4c and heat the plasma.

Furthermore, during operation, due to the temperature rise of the finned pie f21, a difference in thermal expansion occurs between the waveguide f6 and the finned 9-ear 021, but the difference in thermal expansion is absorbed by the deflection of the wave spring 22. is possible. Note that the guard limiter of the above embodiment
Although the distal end portion of 24 is divided into two pieces, it may be composed of two plates with slits.

As described above, according to this embodiment, the radial direction where the heat flux is relatively small is cooled by the finned pipe 21, and the circumferential direction where the heat flux is large is cooled by the guard limiter 24 made of a high melting point material.
Since it is cooled through the plasma, it can withstand high heat flux from plasma and can be used for long-time operation. Also jacket 20a.

20b is attached to the waveguide 6 as an elastic body.
By providing 2t, the thermal stress generated in the finned part 9 and f21 can be significantly reduced, resulting in a longer service life.

[Effects of the Invention] As described above, according to the present invention, it is composed of a jacket and a finned/arm rib, and a guard limiter is provided in the circumferential direction where the heat flux is large, and a refrigerant is circulated through these. Since it is cooled, it is possible to provide a Faraday shield with improved quality and performance that can withstand high heat flux from plasma and can be used for long-term operation.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing an embodiment of a Faraday shield according to the present invention, FIG. 2 is a sectional view taken along line IV-IV in FIG. 1, and FIG. 3 is a sectional view taken along line V-V in FIG. 2. 4 are schematic configuration diagrams of a high-frequency heating device, and FIG. 5 is a perspective view showing a conventional Faraday shield. 6... Waveguide, 20h, 20b...φ jacket, 2
1...With fin/arm iso, 22...Wave spring, 24.
Buddha Guard Limiter-125... Supply pipe, 26.
...Emission? IF0゜Applicant's agent Patent attorney Takehiko Suzue Figure 1 Figure 5

Claims (3)

[Claims] (1) Attached to the tip of the waveguide for high-frequency heating equipment,
The magnetic field created by the high-frequency current guided by the waveguide acts on the plasma outside the waveguide, electrostatically shields the waveguide, and removes high energy from the plasma outside the waveguide. A Faraday shield that prevents particles from entering the waveguide includes a pair of jackets attached to both sides of the tip of the waveguide, and a number of fins connected to each jacket to allow coolant to pass through. 1. A Faraday shield comprising a guard limiter made of a high melting point material and attached to the side opposite to the waveguide of the jacket. (2) The Faraday shield according to claim (1), wherein the jacket is attached to the waveguide via an elastic body. (3) The Faraday shield according to claim (1), wherein the guard limiter is divided into two pieces at its distal end and provided with a slit so that the divided pieces overlap each other.