JPS5825996B2 - Toroidal coil of torus-shaped 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 l Q A /@74, 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 will be huge, so round steel tubes or square steel tubes are used in the copper strip with grooves to accommodate the cooling pipes. Low-temperature brazed steel pipes 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 Figure 1.

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 consists of upper and lower parts, and cooling pipes 2a and 2b are connected to thick coil conductors 1a and 1b, respectively.
The accommodation grooves 1c and Id are low-temperature brazed.

In the example of FIG. 1, the flow of a cooling medium such as cooling water enters from A and exits from B, but the flow may be reversed.

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 the cooling pipes 2a and 2b from one side end A, and moves in the longitudinal direction of the coil 1 while removing heat from one side of the coil conductors 1a and 1b, and flows to the other end C on one side of the coil conductor 1a and 1b. go up to

Now, change the direction in the width direction of the coil conductors 1a, 1b, move to the other end 2 of the cooling pipes 2a, 2b on the other side of the conductor, and reverse the direction in the longitudinal direction of the coil 1 while removing heat from this side. The water returns and exits as high-temperature water from the other end of the cooling pipe.

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.

The theoretical calculation values when the conductor cooling pipe structural model shown in Fig. 3 is energized are shown in Fig. 4. 65 is the cooling water temperature curve, and 6 is the conductor temperature curve.
If there is a temperature difference in the width direction, the thermal stress in the width direction of the coil conductor increases because the coil 1 is firmly supported within the can, making it difficult to provide a large coil with a high current density. It was impossible.

This invention has been made in view of the above-mentioned current situation, and includes providing a housing groove in the center of the coil conductor in the widthwise direction and in the longitudinal direction, and inside the housing groove, an outer pipe and an inner pipe are used to conduct the outward and outward paths of the cooling medium. A double cooling pipe with a return path is fixed, and the cooling medium is made to flow in opposite directions in the outward and return paths in this double cooling pipe, thereby reducing the temperature gradient in the width direction of the coil conductor. The purpose of the present invention is to provide a toroidal coil for a torus-shaped fusion device that can reduce thermal stress.

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

First, the outer tube 3 and the inner tube 4 are firmly fixed together by electron beam welding or the like via the partition plate 7 to form the double cooling tube 9.

This double cooling pipe 9 is connected to a longitudinal accommodation groove 10a provided in the widthwise center of each coil conductor 1a, 1b,
10b, and is brazed and fixed using low-temperature solder 8.

A cooling medium such as cooling water flows from the outer pipe 3 at one end of the double cooling pipe 9 through an outward path between the outer pipe 3 and the outside of the inner pipe 4 as shown by arrow A. At the other end, it enters the return path of the inner tube 4 as shown by arrow B, flows in the opposite direction as shown by arrow C, and is discharged to the outside.

In the coil 1 having such a cooling structure, the coil conductor 1a,
The heat generated in 1b is transferred to the double cooling pipe 9 placed in the center of the conductor.
The low-temperature cooling medium flowing in the longitudinal direction between the outside of the outer tube 3 and the outside of the inner tube 4 is absorbed, and the cooling medium whose temperature has increased by exchanging heat with the coil conductors 1a and 1b is returned to the inside at the ends of the coil conductors 1a and 1b. It enters the pipe 4, flows in the opposite direction through the return path, and is discharged.

Therefore, the temperature distribution in the secondary direction of the coil conductors 1a, lb becomes uniform, so that the thermal stress in the conductor width direction caused by the coil side surfaces being firmly supported by cans or the like can be significantly reduced.

As described above, according to the present invention, the coil conductor is provided with an accommodation groove in the widthwise central part and in the longitudinal direction, and the outward and return paths for the cooling medium are formed in the accommodation groove by the outer tube and the inner tube. The double cooling pipe is fixed, and the cooling medium is passed in the longitudinal direction from the outer pipe at one end of the double cooling pipe in the outward path, and then flows into the inner pipe forming the return path at the other end of the double cooling pipe to flow in the opposite direction. Since it is made to flow and flow out from one end side of the double cooling pipe, the temperature in the width direction of the coil conductor can be made uniform, and the thermal stress of the coil can be reduced.

[Brief explanation of drawings]

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 coil 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. V in figure 5
It is a sectional view taken along the I-VI line. 1... Coil, 1a, 1b... Coil conductor, 3... Outer tube, 4... Inner tube, 9.
...Double cooling pipe, 10a, 10b...Accommodation groove. In addition, in the figures, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] 1? A housing groove of the e-cooling tube is located at the center in the width direction, and an outward path and a return path are formed by a coil conductor, an outer tube, and an inner tube provided in the longitudinal direction, and a double cooling tube is fixed in the housing groove, The cooling medium flows in the longitudinal direction from the outer tube at one end of the double cooling tube in the outward path, and flows in the opposite direction by flowing into the inner tube forming the return path at the other end of the double cooling tube. A toroidal coil for a torus-shaped nuclear fusion device, characterized in that the coil conductor is cooled by flowing water from one end side of a heavy cooling pipe.