JPS61225797A - High frequency heater for nuclear fuser - 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 [Technical Field of the Invention] The present invention relates to a high-frequency heating device used for plasma heating in a nuclear fusion device.

(Technical Background of the Invention) As is well known, plasma heating for nuclear fusion devices uses Joule heating, which heats the plasma by passing an IR flow through it, as well as second heating.
Stage heating methods include the neutral particle bulk heating method and the high frequency heating method. The high frequency heating method is a method of increasing the plasma temperature by absorbing high frequency electromagnetic energy into the plasma.

High frequency heating using this high frequency heating method is described in ill 11 part 1. as shown in FIG. 2, for example. Power supply section 2° High frequency excitation amplification section 3. N force amplification section 4. Supply 11WA5° transmission system6. High frequency heating coupling system7. Consists of cooling section 8 etc.
The small power high frequency generated in the high frequency excitation amplification section 3 is amplified to a layer width of MW class per electron tube in the power amplification section 4, and then passed through the power supply section 5 and the transmission system 6 to the plasma 9 by the high frequency heating coupling system 7. It is designed to be incident. In addition, -1 in the figure
0 indicates a blank, and 11 indicates a toroidal coil.

As shown in FIG. 3, the high-frequency heating coupling system 7 of this high-frequency heating device includes a launcher 13 including a loop antenna 12 for injecting electromagnetic waves into plasma, and an impedance matching device 14.
and a coaxial feed line (or waveguide) 15, through which high frequency power from the transmission system 6 is transmitted to the launcher 13. In addition, since this high frequency heating coupling system 7 is directly coupled to the furnace side, a partition wall 16 made of ceramic or the like is provided inside the coaxial feeder line 15, and with this partition wall 16 as a border, the furnace side is kept under high vacuum. The coaxial feed line 15 on the transmission system 6 side, which is partitioned by the partition wall 16, is filled with SFs gas 17 as an insulating gas in order to increase the dielectric strength.

[Problems with background technology]

By the way, in the high-frequency heating coupling system 7 configured as described above, a very large ^-frequency power is accumulated in the part filled with SFs gas (hereinafter referred to as the SFs gas-filled part) due to the coupling characteristics of plasma and high-frequency power. A large high frequency loss occurs on the surface of the SFs gas filled part. However, plasma heating in nuclear fusion devices is not performed continuously, but in pulses over extremely short periods of time, with a pause period before the next heating, and this process is repeated. Because the scale of the nuclear fusion experimental device was small and the heating time was short, a large temperature rise due to high frequency loss did not occur in the SFs gas-filled section, and no special cooling measures were taken.

However, as the scale of the experimental equipment increases and the heating time exceeds 1 second, natural cooling cannot keep up and a large temperature rise occurs, causing excessive thermal stress in various parts of the SFs gas filling section. There is a possibility that the coaxial power supply line may become damaged due to thermal expansion or thermal deformation. In order to avoid this temperature rise, for example, it is possible to increase the size of the coaxial power supply line, but there are spatial restrictions around the installation location of the coaxial power supply line, and a separate refrigerant supply device can be connected. It is necessary to forcibly cool the outer wall of the coaxial power supply line by doing something like this.

However, in a coaxial feeder, the concentration increase is greater on the inner wall than on the outer wall, and SFs gas is a highly insulating gas, so it is extremely difficult to remove heat from the inner wall by cooling only the outer wall. Therefore, one possible cooling measure is to cool the inside of the inner wall by flowing a refrigerant, but the inside of the inner wall is not necessarily hollow, and the cooling structure is complicated considering the requirement to maintain insulation between the inner and outer walls. This may reduce the reliability of the high-frequency heating device in terms of maintaining performance.

In addition, if sparks occur inside the coaxial power supply line due to fluctuations in high frequency characteristics during operation, the SFs gas will decompose and impurities will be mixed in the gas, and these impurities may deteriorate the insulation properties of the SFs gas. However, due to the infrequent occurrence of these incidents, conventional small-scale nuclear fusion experimental equipment did not take any special measures, instead replacing the SFs gas as necessary. However, if the scale of the fusion device is larger than that of an experimental device, stopping operation for gas exchange will lower the operating rate and is not desirable from the standpoint of operating costs.

[Purpose of the invention]

The present invention has been made based on the above circumstances, and its purpose is to eliminate the need for spatial expansion around the installation location of a coaxial feeder or waveguide filled with insulating gas. An object of the present invention is to provide a highly reliable high-frequency heating device for a nuclear fusion device, which can suppress temperature rise due to high-frequency loss with a simple configuration, and whose insulation properties do not deteriorate even if impurities are generated in the gas.

[Summary of the invention]

In order to achieve the above object, the present invention connects a gas circulation device to the SFs gas filling section, and uses this gas circulation device to
The Fs gas is circulated and cooled by a gas cooler installed in the circulation path, and impurities and fine particles in the gas are removed by an adsorption tower and filter also installed in the circulation path. .

[Embodiments of the invention]

Hereinafter, one embodiment of the present invention will be briefly described with reference to the drawings.

FIG. 1 is a block diagram of a gas circulation device showing an embodiment of the present invention, and this gas circulation device circulates through the SF6 gas discharge nozzle 7a and the SFs gas supply nozzle 7b of the high frequency heating coupling system 7 shown in FIG. A gas circulation blower 22 is connected to the circulation loop 21 through a loop 21 . Heat exchanger (gas cooler)
23. Adsorption tower 24. and a filter 25. Therefore, the SFs gas 17 filled in the SFs gas filling part of the high frequency heating coupling system 7 flows into the circulation loop 21 from the SFs gas discharge nozzle 7a by the gas circulation machine 22, and flows into the circulation loop 21 through the heat exchanger 23 and the adsorption tower 24. ．．
The gas passes through the filter 25 and returns to the SFs gas filling section of the high frequency heating coupling system 7 from the SFs gas supply nozzle 7b.

In the above configuration, for example, the SF of the high frequency heating coupling system 7
When the temperature of the SFs gas 17 filled in the s gas filling section rises due to accumulation of high frequency power, the gas circulation device of this embodiment is activated to circulate the SFs gas 17. At this time, the SF flowing through the circulation loop 21 by the gas circulation blower 22
The s gas 17 is cooled in a heat exchanger 23, and further passed through an adsorption tower 2.
After impurity gas and fine powder generated in the SFs gas 17 are removed by the SFs gas 17 and the filter 25, the SFs gas 17 is returned to the SF6 gas filling part of the high frequency heating coupling system 7 through the SFs gas supply nozzle 7b.

By connecting the gas circulation device to the SFs gas filling part of the high frequency heating coupling system 7 in this way, the high frequency heating coupling system 7
The SFs gas filling section is always filled with cooled and purified S.
Since the Fs gas 17 is supplied, an increase in concentration due to heat generation can be prevented, and at the same time, deterioration of insulation properties due to impurities can be prevented. Furthermore, since the SFs gas 17 is used as a refrigerant as it is, there is no need for a complicated cooling structure, and since the gas circulation device can be placed separately, there is no need to expand the space around the coupling system. Furthermore, even if impurities or fine powder are generated, they are removed, so the cleanliness of the SFs gas 17 can be maintained for a long time, and the period of gas exchange can be significantly extended.

Note that the present invention is not limited to the above embodiments.

For example, the adsorption tower 24 and filter 25 do not necessarily need to be installed in the circulation loop 21, and may be appropriate membranes depending on the operating conditions. Further, in the above embodiment, a high frequency heating coupling system using a coaxial feeder was described, but a similar effect can be obtained with a high frequency heating coupling system using a waveguide.

Furthermore, it goes without saying that the present invention can also be applied to a transmission system 6 filled with SF6 gas.

〔Effect of the invention〕

As is clear from the above description, the present invention provides a high-frequency heating device for a nuclear fusion device that can stably transmit large high-frequency power for a long time by connecting a gas circulation device to the insulating gas filling part of the high-frequency heating device. Can be provided.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of a gas circulation device showing an embodiment of the present invention, Fig. 2 is a block diagram showing an example of a high frequency heating device, and Fig. 3 is a schematic configuration showing an example of a high frequency heating coupling system of the same device. It is a diagram. DESCRIPTION OF SYMBOLS 1... Control part, 2... Power supply part, 3... High frequency excitation amplification part, 4... Power amplification part, 5... Power supply part, 6...
・Transmission system. 7...High frequency heating coupling system, 9...Plasma, 12.
...Loop antenna, 13...Launcher, 14...
Impedance matching device, 15... coaxial feed line (or waveguide). ,, 16-...Partition wall, 17-8Fs gas, 7a・S
Fs gas discharge nozzle, 7b...SFs gas supply nozzle. 21... Circulation loop, 22... Gas circulation blower. 23... Heat exchanger (gas cooler), 24... Adsorption tower. 25...filter. Applicant's agent Patent attorney Takehiko Suzue Figure 1 Figure 2 Figure 3

Claims (4)

[Claims] (1) A high-frequency heating device having an insulating gas filling section in which a part of a coaxial feeder line or a waveguide is filled with insulating gas, characterized in that a gas circulation device is connected to the insulating gas filling section. High frequency heating equipment. (2) The nuclear fusion according to claim (1), wherein the gas circulation device includes a gas circulation blower, a gas cooler, and means for removing impurities in the gas. High frequency heating device for equipment. (3) The high-frequency heating device for a nuclear fusion device according to claim (2), wherein the impurity removing means is an adsorption tower or a filter, or both. (4) The high-frequency heating device for a nuclear fusion device according to claim (1), wherein the insulating gas is SF_6 gas.