Insulation treatment method for helium inlet pipe of superconducting magnet

Disclosed is an insulation treatment method for a helium inlet pipe of a superconducting magnet. The superconducting magnet has a structure with varying T-shaped cross section. The irregular parts of the magnet are filled with G10 to reduce the difficulty in the insulation treatment caused by the irregular shape. Moreover, a skirt-shaped insulating material is provided around the metal conduit to overcome the reduction in the insulation electrical performance caused by the defects in the insulation treatment for such irregular parts. The application designs a sample structure for insulation treatment, and can wrap the superconducting magnet having the T-shaped varying cross-section with insulating materials before vacuum pressure impregnation, meeting special requirements of high-voltage insulation treatment for the superconducting magnet with a complex structure under low temperature and vacuum environment.

TECHNICAL FIELD

The present application relates to insulation treatment for a superconductor in a nuclear fusion device, and more particularly to an insulation treatment method for a helium inlet pipe of a superconducting magnet.

BACKGROUND

Thermonuclear fusion, as one of ultimate energy solutions, will provide humans with inexhaustible clean energy. In the international thermonuclear experimental reactor (ITER) under construction, a superconducting magnet, as one of the most crucial components, is generally exposed to a very harsh working environment such as complex mechanical and electromagnetic conditions and thermal stress loads, so there are relatively high requirements for the electrical insulation properties of the magnet. During the insulation treatment of the magnet, the insulation treatment for the irregular parts of the magnet plays a crucial role in affecting the insulation performance of the magnet. Among such parts, the helium inlet pipe of the superconducting magnet for cooling, due to the high irregularity in shape, is required to be designed into a special insulation structure before the vacuum pressure impregnation with insulating resin, ensuring the magnet to have satisfactory insulation properties after the vacuum pressure impregnation.

SUMMARY

An object of this application is to provide an insulation treatment method for a helium inlet pipe of a superconducting magnet to ensure the superconducting magnet to have satisfactory insulation properties at the irregular parts after the vacuum pressure impregnation with a resin, which is of great engineering significance for the insulation treatment of a magnet with an irregular shape.

The technical solutions of this application are described as follows.

The application provides an insulation treatment method for a helium inlet pipe of a superconducting magnet, comprising:

welding an end of a metal conduit to an outer surface of a superconducting conductor;

wrapping an outer surface of the metal conduit with a composite insulating tape;

covering the outer surface of the superconducting conductor with fiberglass cloth;

filling spaces around a junction between the metal conduit and the superconducting conductor with G10, and fixing the G10 to the metal conduit and the superconducting conductor with a binding tape;

covering the G10 with a skirt-shaped insulating material with the metal conduit as a center; and

fixing the skirt-shaped insulating material to the metal conduit and the superconducting conductor with the binding tape;

wherein the binding tape is made of a composite insulating material.

In some embodiments, the composite insulating tape, the binding tape and the skirt-shaped insulating material are all made of a composite material of the fiberglass cloth and a polyimide film; and the G10 is a composite material composed of fiberglass and epoxy resin.

This application has the following beneficial effects.

In the application, the irregular parts of the magnet are filled with G10 to reduce the difficulty in the insulation treatment caused by the irregularity. Moreover, a skirt-shaped insulating material is provided around the metal conduit to alleviate the decrease in the insulation electrical performance caused by the defects in the insulation treatment due to the irregular shape.

DETAILED DESCRIPTION OF EMBODIMENTS

This application provided an insulation treatment method for a helium inlet pipe of a superconducting magnet, and a structure involved therein was shown inFIGS. 1 and 2. The method was specifically implemented as follows.

1) A metal conduit1is welded to a superconducting conductor2.

2) Fiberglass cloth3is attached to a surface of the superconducting conductor2.

3) The metal conduit1is wrapped with a composite insulating tape4.

4) Spaces around a junction between the metal conduit1and the superconducting conductor2are filled with G105.

5) The G105is fixed by winding with a binding tape6.

6) The G105around the metal conduit1is covered with a skirt-shaped insulating material7, which is fixed by winding with the binding tape6.

7) Step (6) is repeated to obtain the desired dielectric strength.

8) The part obtained in step (7) is subjected to insulation curing through vacuum pressure impregnation.

9) A dielectric withstand voltage test is performed on the part.

The composite insulating tape4, the binding tape6and the skirt-shaped insulating material7are all made of a composite material of the fiberglass cloth and a polyimide film; and the G10 is composed of fiberglass and epoxy resin.