JPS5913718B2 - Fusion device upper mount - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a stand for a nuclear fusion device, and more particularly to a stand for a metal nuclear fusion device that supports a group of coils such as a toroidal coil and a poloidal coil.

A nuclear fusion device is a device that stably confines high-temperature, high-density deuterium or tritium plasma for a certain period of time and extracts the energy generated by fusing the high-temperature atomic nuclei.

Among these, a magnetic confinement type fusion device is one in which high-temperature plasma is confined by a magnetic field system.

This magnetic confinement type fusion device uses electromagnetic force and pressure of the magnetic field based on the interaction between the magnetic field system and the plasma current.
Contains plasma by canceling plasma pressure and electromagnetic force.

Therefore, a magnetic confinement type fusion device has a coil system that generates various magnetic fields suitable for each purpose, and a support structure that supports the electromagnetic force generated in this coil system.

In addition, various magnetic fields are required to have very high spatial and temporal precision in order to improve plasma performance.

It can be said that the higher the precision of the magnetic field, the better the performance of the fusion device.

1 and 2 show a torus-type fusion device as an example of a magnetic confinement type fusion device, and a conventional example will be explained.

In the figure, reference numeral 10 denotes a nearly donut-shaped vacuum container in which plasma 9 is housed.

2 surrounds the vacuum vessel 10 and extends in the torus circumferential direction 1
A plurality of toroidal magnetic fields 3 are arranged at predetermined intervals.
It is a toroidal coil that makes.

Outside this toroidal coil 2, there is a current transformer coil 4 that creates a current transformer magnetic field 13 along the torus circumferential direction 1 of the vacuum vessel 1, and a vertical magnetic direct coil 5 that creates a vertical magnetic field 14 (hereinafter, both coils are referred to as a poloidal coil 6). ) are arranged.

The toroidal coil 2 and the poloidal coil 6 support the electromagnetic force and the like acting on each of them.
It is firmly supported by the lower frame 8 via a support or the like.

By the way, as shown in FIG.
is suddenly changed over time to generate an electric field in the circumferential direction 1 of the torus to discharge the fuel gas in the vacuum vessel 10, thereby causing a plasma current 11 to flow in the circumferential direction 1 of the torus, increasing the temperature of the plasma 9 due to Joule loss. made by letting

Therefore, the plasma 9 is confined by the magnetic field in the form of a plasma current 11, and the loaded particles are wound around the toroidal magnetic field 3 and move in the circumferential direction 1 of the torus.

On the other hand, due to the pressure of the plasma 9 and the electromagnetic force of the plasma current 11, a force is generated in the plasma 9 to displace it in the direction 12 to the outside of the torus.

The vertical magnetic field 14 by the vertical magnetic field coil 5 interacts with the plasma current 11 to direct the plasma 9 in the toroidal direction 1
This generates an electromagnetic force that causes a displacement of 5.

In order to confine the plasma 9 in the center of the vacuum vessel 10, the force in the torus outer direction 12 and the torus inner direction 1 must be
It is necessary that the forces of 5 are balanced.

Therefore, the strength Br of the vertical magnetic field 14 is determined as a function f of various plasma parameters as shown in the following equation.

Here, Br: Strength of vertical magnetic field 14 ■P: Plasma current 11 R: torus radius at plasma center a: Torus radius of plasma 9 T: Temperature of plasma 9 11: Standardization of plasma current loop internal inductance It is.

On the other hand, the plasma 9 is very unstable, and the plasma parameters change rapidly in a short period of time due to changes in the plasma current 11 distribution, interaction between the plasma 9 and the vacuum vessel 10, and the like.

In order to stably confine the plasma 9 for a long time even under these changes, it is necessary to control the vertical magnetic field 14 to follow the changes in the plasma parameters.

For this reason, the current of the vertical magnetic field coil 5 can usually be changed rapidly following the plasma parameters.

In this way, the current of the poloidal coil 6 can be changed rapidly over time in order to generate plasma 9 and to stably confine plasma 9.

On the other hand, the poloidal coil 6 supports electromagnetic force and the like, and is surrounded by a lower frame 8.

Generally, the lower pedestal 8 is made of a metal material.

In order to increase mechanical strength, it is desirable that the upper and lower pedestals 8 be integrated in the circumferential direction 1 of the torus.

However, when the upper and lower pedestals 8 are integrated, large eddy currents (induced currents) flow in the upper and lower pedestals 8 due to sudden changes in the current of the poloidal coil 6, and the magnetic field due to the eddy currents is generated in the plasma 9. By disturbing the acting magnetic field, plasma 9
This reduces the confinement properties of

Therefore, the conventional fusion device mount has a structure in which the lower mount 8 is divided into a plurality of parts in the torus circumferential direction 1 and electrically insulated in the torus circumferential direction 1.

However, as nuclear fusion devices become larger,
When the electromagnetic force supported by the lower pedestal 8 increases and higher precision of the magnetic field is required, the upper and lower pedestals 8 are divided in the torus circumferential direction 1 and electrically insulated to reduce eddy currents. When trying to improve the magnetic field accuracy, the upper and lower mounts 8
There was a drawback that the number of zero divisions was extremely large, resulting in a significant decrease in mechanical strength.

The present invention has been made in view of the above-mentioned points, and its purpose is to prevent eddy currents from being generated without reducing the mechanical strength of the pedestal even if the upper and lower pedestals are divided in the circumferential direction of the torus. The objective is to provide a mount for a nuclear fusion device that can effectively reduce the amount of energy generated.

The present invention supports a toroidal coil and a poloidal coil, and also supports a plurality of metallic upper and lower frames that are divided in the circumferential direction of the torus. The desired purpose is achieved by having an electrically high-resistance portion in the circumferential direction of the torus that extends to approximately the center of the radial dimension of the torus.

That is, as shown in FIG. 3, the current transformer coils 4 are normally arranged with a special spatial arrangement so that the current transformer magnetic field 13 due to the current transformer coils 4 is hardly generated in the plasma 9 region.

The vertical magnetic field coil 5 is also spatially arranged to create a vertical magnetic field 14 with a special spatial distribution in the plasma 9 region.

Therefore, once the size of the device is determined and the region of the plasma 9 is determined, the arrangement of the current transformer coil 4 and the vertical magnetic field coil 5 is also determined to some extent.

On the other hand, if it is assumed that the upper and lower frames 8 are also supported near the point where a load such as an electromagnetic force is generated, the arrangement thereof is determined to some extent.

For this reason, the current transformer magnetic field 13 that intersects with the upper and lower mounts 8,
The vertical magnetic field 140 distribution is common in torus-type nuclear fusion devices regardless of the device in relation to the region of plasma 9 including the torus effect.

In other words, as shown in FIG. 4, the magnetic field component in the vertical direction 16 that intersects with the pedestal 8 is
The distribution becomes such that the size rapidly decreases with the boundary near o.

Therefore, as shown in FIG.
If we simply divide the torus circumferential direction 1, the eddy current 1
7 is divided with its center near the torus radius R6, which is approximately the center of the plasma, and is distributed around each of the lower frames 8.

Therefore, the present invention focuses on this eddy current.

Hereinafter, the present invention will be described in detail based on embodiments of the drawings.

The same reference numerals will be used for the same items as before.

FIG. 6 shows an embodiment of the present invention.

Since the schematic configuration is almost the same as the conventional one, the explanation here will be omitted.

As shown in the figure, in this embodiment, the torus is divided into a plurality of parts in the circumferential direction, and each of the divided parts of the lower pedestal 8 has a part in the middle of the torus circumferential direction 1 and from the torus center side 18 in the torus radial direction. A slit 19 is provided in the torus to form an electrically high resistance portion in the circumferential direction 1 of the torus.

This slit 19 is provided at approximately the center (torus radius R8) t of the torus radial dimension of the divided frame.

With this configuration of this embodiment, the eddy current 1
70 distribution is almost the same as in the case where the conventional upper and lower pedestals 8 are divided into many parts, and just by providing the slits 19, the same eddy current reduction effect as the conventional one can be obtained, and the mechanical Since the number of divided parts is reduced, the strength is greatly improved.

In the above embodiment, the slits 19 are provided to form electrically high resistance parts in the circumferential direction 1 of the torus of the upper and lower pedestals 8. A similar effect can be obtained by using a high-resistance material, or a resistance anisotropic material such as carbon fiber.

According to the above-described mount for a nuclear fusion device of the present invention, the toroidal coil and the poloidal coil are supported, and the metal upper and lower mounts are divided into multiple parts in the circumferential direction of the torus, and each of the divided parts is connected to the torus. In the middle of the circumference,
In addition, since an electrically high-resistance portion is formed in the circumferential direction of the torus extending from the center side of the torus to approximately the center of the radial dimension of the torus, increasing the number of divided portions of the pedestal will reduce the eddy current. This kind of mount can be obtained with high mechanical strength and is very effective when used in a nuclear fusion device.

[Brief explanation of drawings]

Figure 1 is a partially sectional plan view of a torus-type nuclear fusion device that uses a conventional mount, and Figure 2 is A--A in Figure 1.
A sectional view, Figure 3 is an explanatory diagram explaining the magnetic field near the upper and lower mounts, Figure 4 is a characteristic diagram showing the magnetic field distribution that intersects with the mount at the torus radial position, and Figure 5 is the mount in the toroidal direction. FIG. 6 is a partial plan view showing a subdivided conventional example, and FIG. 6 is a partial plan view of a frame showing an embodiment of the present invention. 1... Torus circumferential direction, 2... Toroidal coil, 3... Toroidal magnetic field, 4...
...Current transformer coil, 5...Vertical magnetic field coil,
6...Poloidal coil, 8...Top,
Lower mount, 9...Plasma, 10...
Vacuum container, 11... Plasma current, 12...
... Torus outside direction, 13 ... Current transformer magnetic field, 14 ... Vertical magnetic field, 15 ... Torus inside direction, 16 ... Up and down direction, 17...
...Eddy current, 18...Torus center side, 19.
·····slit.

Claims (1)

[Scope of Claims] 1. A plurality of toroidal coils surrounding the vacuum vessel and arranged at predetermined intervals in the circumferential direction of the torus in order to retain plasma in the vacuum vessel; In a fusion device mount comprising a metallic upper and lower mount which supports a plurality of poloidal coils to be arranged and is divided into a plurality of parts in the circumferential direction of the torus, each of the upper and lower mounts is divided into two parts. , a stand for a nuclear fusion device, characterized in that it has an electrically high resistance part in the circumferential direction of the torus, which extends from the center of the torus to approximately the center of the radial dimension of the torus, in the middle of the circumferential direction of the torus; . 2. The fusion device mount according to claim 1, wherein the electrically high resistance portion is formed by providing slits in the torus radial direction of the upper and lower mounts. 3. The fusion device mount according to claim 1, wherein the electrically high-resistance portion is formed with ceramic interposed in the torus radial direction of the upper and lower mounts. 4. The fusion device pedestal according to claim 1, wherein the electrically high-resistance portion is formed with carbon fibers interposed in the radial direction of the torus of the upper and lower pedestals.