JPS5825998B2 - Toroidal coil of torus fusion device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a toroidal coil for a torus-shaped nuclear fusion device in which a cooling medium is passed through the coil conductor for cooling.

A plurality of toroidal coils in a nuclear fusion device are arranged in the toroidal direction, and a large current is passed through the coils to create a strong magnetic field for plasma confinement.

Since the current density of the coil conductor is required to be several tens of A/mi, forced cooling is usually performed using a cooling medium such as cooling water.

If the device is small, a hollow conductor is often used as the coil conductor, but if the device is large, the hollow conductor manufacturing equipment is huge, so round steel pipes are used in the copper strip with grooves to accommodate cooling pipes. Alternatively, square steel pipes brazed at low temperatures are used.

The conventional method and the present invention are in the latter case.

The cooling structure of a conventional toroidal coil is shown in FIG.

Figure 1 shows a toroidal coil of the upper and lower halves, which has recently been widely adopted.

Although the number of coil turns is 3 turns for convenience, it is usually about 10 turns.

The coil is usually firmly attached to a can (not shown) made of non-magnetic material to withstand strong electromagnetic force.

As shown in FIG. 2, the coil 1 consisting of the upper and lower parts has cooling pipes 2a and 2b with thick coil conductors 1a and 2b, respectively.
The housing grooves 1c and 1d of 1b are low-temperature brazed.

In the example of FIG. 1, the flow of the cooling medium such as cooling water comes out from the inlet from A, but the opposite may be possible.

The heat generated by the coil when the coil is energized is removed by the cooling medium as follows.

Cooling water at a low temperature enters from one side end A of the cooling pipes 2a and 2b, and moves in the longitudinal direction of the coil 1 while removing heat from one side of the coil conductors 1a and 1b, to the other end of one side. Go to the specific location.

Here, the coil conductor 1a. It changes its direction in the width direction of the coil 1b and moves to the other end of the cooling pipe 2a t 2b on the other side of the conductor, and returns to the longitudinal direction of the coil 1 while removing heat from this side. The water exits as high-temperature water from the end of the side.

The conventional structure has the following drawbacks when a large current density is required, such as recent nuclear fusion experimental equipment.

That is, due to the long cooling path in the longitudinal direction of the conductor, the large width of the conductor, etc., a large temperature gradient occurs in the width direction of the conductor.

FIG. 4 shows the theoretically calculated values of the temperature distribution when the conductor cooling structure model shown in FIG. 3 is energized.

5 is a cooling water temperature curve, and 6 is a conductor temperature curve.

Because the coil 1 is firmly supported within the can due to the temperature difference in the width direction, the thermal stress in the width direction of the coil conductor increases, making it possible to provide a large coil with a high current density. was impossible.

This invention was made in view of the current situation as described above.
A slit is formed in the length direction in the middle of the coil conductor in the width direction, and this slit forms thermal insulation between both sides of the coil conductor in the width direction, reducing heat flow between them and reducing thermal strain in the width direction. It is an object of the present invention to provide a toroidal coil for a torus-shaped nuclear fusion device, which can reduce thermal stress in the width direction of a coil conductor by escaping through slits.

An embodiment of the present invention will be described below with reference to FIGS. 5 and 6.

The coil conductor 1 a t 1 b is provided with accommodation grooves 1 e in the longitudinal direction on both sides in the width direction.

Cooling pipes 2a and 2b are brazed and fixed in these grooves with low-temperature solder 4.

The coil conductors 1a, 1b are provided with slits 7 intermittently in the longitudinal direction at the center in the width direction.

In the above embodiment, the cooling pipes 2 a t 2 b are embedded in the center of the thickness direction of both side surfaces of the coil conductors 1 a and 1 b, but the cooling pipes 2 a and 2 b are embedded in housing grooves on both sides of the front or back surfaces of the coil conductors 1 a and 1 b. 7 may be provided and fixed by low temperature brazing or the like.

The slit 7 may be formed in a wide conductor by machining, or by cutting two conductors with a gap between them.
That is, the coil conductors 1at1b are arranged with a gap in the middle in the width direction, and thermally insulating coupling pieces such as ceramics are applied at pitches with slits of appropriate length in the longitudinal direction, and both conductors are connected with this coupling piece. Intermediate brazing may also be used to connect.

The conductor 1a of the coil constructed in this way.

1b, a thermal insulating layer is formed in the width direction to prevent heat conduction in the width direction, and the temperature gradient in the width direction is reduced in both coil conductors divided by the 7 slits, reducing thermal stress. Ru.

Furthermore, the thermal stress in the width direction caused by the coil conductor having its side surfaces firmly supported by cans or the like can be absorbed by the escape of the slit portion.

In the above embodiment, one slit 7 is provided at the center of the coil conductor in the width direction, but a plurality of slits 7 may be provided in parallel in the longitudinal direction if there is no structural problem.

In this case, if you zigzag the parallel slits,
It will be even more effective.

As described above, according to the present invention, slits are formed at an appropriate pitch in the longitudinal direction in the middle of the coil conductor in the width direction,
These slits form thermal insulation between both sides of the coil conductor in the width direction to reduce heat flow between them, and the thermal strain in the width direction is released through the slits, so thermal stress in the width direction of the coil conductor This has the effect of easily reducing

[Brief explanation of the drawing]

Figure 1 is a perspective view showing a conventional toroidal coil divided into upper and lower parts, Figure 2 is a sectional view taken along the line ■-■ in Figure 1, and Figure 3 is a model coil conductor with the cooling structure shown in Figure 1. A perspective view of
4 is a temperature curve diagram of the conductor and cooling water in the cooling pipe shown in FIG. 3, FIG. 5 is a partial side view showing an outline of a coil conductor cooling structure according to an embodiment of the present invention, and FIG. It is a sectional view taken along the line ■-■ in the figure. 1... Coil, 1a, 1b... Coil conductor, 1e... Accommodating groove, 2 a, 2 b.
...Cooling pipe, 7...Slit. In addition, in the figures, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Scope of Claims] 1. A coil conductor in which housing grooves for cooling pipes are provided in the longitudinal direction on both sides with respect to the width direction, and slits are provided in the middle at appropriate pitches in the longitudinal direction, and the coil conductor is disposed and fixed in the housing grooves. A toroidal coil of a torus-shaped nuclear fusion device characterized by being equipped with a cooling pipe that circulates a cooling medium. 2. The toroidal coil for a torus-shaped nuclear fusion device according to claim 1, wherein a plurality of slits are provided in parallel in the longitudinal direction in the middle of the coil conductor in the width direction.