JPS6138489A - Support structure of coil protective pipe in nuclear fusion device - 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 [Field of Application of the Invention] The present invention relates to a support structure for a coil protection tube in a nuclear fusion device, and particularly to a support structure for reinforcing the flexural rigidity of a bellows tube.

[Background of the invention]

For example, a tokamak-type fusion device uses a magnetic field method to confine plasma in a vacuum container. To form this magnetic field, two types of magnetic field coils are arranged orthogonally to each other around a torus-shaped vacuum vessel. That is, these magnetic field coils are called toroidal magnetic field coils and voloidal magnetic field coils. moreover,
In order to keep the plasma confined in a vacuum vessel stable, there is a main magnetic limiter coil that controls the position of the plasma and suppresses generated impurities. This main magnetic limiter coil is housed in a protection tube with a racetrack cross-section and is attached to the inner wall surface of the vacuum vessel.

Since this protective tube is exposed to a high magnetic field, it has a structure in which thin bellows portions and thick ring portions are alternately coupled in order to reduce eddy current loss generated on the surface of the protective tube. Therefore, the protective tube requires a support structure that suppresses deformation of the protective tube in order to avoid contact between the coil housed in the protective tube and the tube wall in response to electromagnetic force received in a magnetic field.

Figure 3 shows the support structure of a conventional coil protection tube. Looking at one sector consisting of the bellows pipe 5, intermediate ring 2, bellows pipe 5, and thick ring 1, the support of the bellows part is as follows.

This is done by using a support ring 6 whose one end is welded to the thick ring 1 and extends so as to surround the bellows part. That is, a stopper 7 of about 20φ is welded or screwed to the support ring 6, and the stopper 7 is brought into contact with the stop ring 3, thereby suppressing the deflection of the bellows portion. Note that 4 in Figure 1 indicates a joining ring.

However, in the above support structure, in order to achieve electrical insulation at the contact point between the stopper 7 and the stop ring 3, it is necessary to insert an insulating material into the contact point or to cover the stopper 7 with an insulating material. high temperature applied to stopper 7;
It is difficult to maintain sufficient strength under high loads. As a result, the support of the protective tube becomes insufficient, which may impair the function of the main magnetic limiter coil.

On the other hand, in Japanese Patent Application Laid-Open No. 57-35791, in order to prevent the protective tube bellows portion from being locally heated by the radiant heat from the plasma, the outer circumference of the protective tube bellows portion is approximately perpendicular to the Koriyama direction. A structure in which multiple liner plates are arranged has been proposed.

However, in this structure, the liner plate made of molybdenum is fixed with bolts to the thick rings that sandwich the bellows, so it is difficult to maintain electrical insulation between the thick rings, and the liner plate is made into a thin strip. Therefore, the liner plate is easily sheared and deformed as the protection tube bends under electromagnetic force, and therefore a sufficient stiffening effect cannot be obtained for the bellows portion of the protection tube.

[Purpose of the invention]

An object of the present invention is to solve the problems of the prior art and to maintain insulation in the bellows portion of a protection tube.

Another object of the present invention is to provide a support structure for a coil protection tube that can strengthen the reduction in rigidity of the bellows portion and firmly support the protection tube.

[Summary of the invention]

According to what the present inventors have analytically clarified and experimentally confirmed, in the case of a protection tube with a bellows part,
Bending deformation of the pipe as a whole becomes a problem due to the action of electromagnetic force. In the case of so-called axially symmetrical deformation, in-plane distortion (shear deformation) has almost no effect on deflection, whereas in the case of bending deformation of the entire protective tube, the in-plane shear stiffness (transverse elastic modulus) It has a large effect on deflection.

It has been analytically confirmed that the in-plane shear stiffness is the controlling factor for the deflection of the protective tube.In view of this, the present invention has developed a non-magnetic structure that suppresses shear deformation by connecting a panel made of an insulating material or a backing plate made of an insulating material. The structure is such that the load is borne by a metal panel, thereby reinforcing the decrease in rigidity of the storage bellows portion.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIG. 1st
The figure shows a perspective view of the support structure of the coil protection tube according to the present invention. In figure 0, the coil protection tube has a thick ring 1
1, an intermediate ring 12, and a bellows pipe element constructed by welding a joining ring 14 to both ends of a linear bellows 15 formed in advance, and the bellows pipe element is inserted between the thick ring 11 and the intermediate ring 12. The thick ring 11 and the intermediate ring 12 are arranged in a circular arc shape, and are welded and connected via the joining ring 14 respectively. A sector consisting of an intermediate ring 12, a bellows tube 15, and a thick-walled ring 11 is used as a structural unit, arranged in a donut shape to form a protection tube torus, and fixed to the inner wall (not shown) of a vacuum vessel of a fusion device at the position of the thick-walled ring. be done.

Thus, the support structure for the coil protection tube according to the present invention includes a panel 16 made of an insulating material that is passed between the thick rings 11, and both ends of the panel 16 are fixed to the thick rings 11 and 11 with bolts 17. The structure is as follows.

Therefore, according to this embodiment, the deflection of the bellows tube 15 portion is suppressed by the in-plane shear rigidity of the panel 16. In other words, the decrease in the flexural rigidity of the bellows tube section is reinforced by the high in-plane shear rigidity of the panel 16, so the support for the protective tube is strengthened, and electrical insulation is achieved between the thick rings 11, thereby preventing eddy currents. Losses are also reduced.

FIG. 2 shows another embodiment of the present invention, which differs from FIG. 1 in that the panel is made of non-magnetic metal, and the middle part of the panel is divided, so that each divided panel 16A, 16B has one end. portions are welded and fixed to the thick ring 11, respectively, and the other end portions of the divided panels 16A and 16B are opposed to each other with an appropriate gap.

At this point, the backing plate 18 made of insulating material is divided into panels 16A.
, 16B, which are connected by tightening with a support bolt 19 from both sides. Note that 20 indicates a welded portion of the divided panel.

In this embodiment as well, the reduced flexural rigidity of the bellows pipe portion is reduced by connecting the divided panels 16A and 1 into one.
Since it is reinforced by the in-plane shear rigidity of 6B, the protection tube can be strongly supported, and since the thick rings 11 are insulated by the contact plate 18 made of an insulating material, eddy current loss can also be reduced.

〔Effect of the invention〕

As described above, according to the present invention, insulation can be maintained in the bellows portion of the protection tube, and reduction in rigidity of the bellows portion can be reinforced, so that the protection tube can be strongly supported.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing one embodiment of a support structure for a coil protection tube according to the present invention, FIG. 2 is a perspective view showing another embodiment of the invention, and FIG. 3 is a conventional support structure for a coil protection tube. FIG. 2 is a partially cross-sectional perspective view. 11...Thick-walled ring, 15...Bellows tube, 16.
・Buzz llID ′jA 2 Figure

Claims (1)

[Claims] Bellows tubes and rings thicker than the bellows tubes are connected alternately to form a donut-shaped protection tube torus, and the protection tube torus is fixed to the inner wall of the vacuum vessel of the fusion device at the ring position. In the coil protection tube, a panel made of an insulating material is passed between the rings, and both ends of the panel are fixed to the rings, or a panel made of non-magnetic metal is passed between the rings, and the middle part of the panel is fixed. A coil protection tube for a nuclear fusion device, characterized in that one end of each divided panel is fixed to a ring, and the other ends of the divided panels are connected via a backing plate made of an insulating material. support structure.