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Feasibility study of large-scale superconducting magnets without layer-to-layer insulation.

无层间绝缘的大型超导磁体可行性研究

基本信息

批准号：
18560296
负责人：
IMAGAWA Shinsaku
金额：
$ 2.09万
依托单位：
National Institute for Fusion Science
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2006
资助国家：
日本
起止时间：
2006 至 2007
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-18560296/
关键词：
Superconducting magnet Electrical insulator Quench protection

项目摘要

At first, the conceptual design of the superconducting magnet in which the supporting structure was used as a protection resistance was advanced. Secondly, the design of the small coil sample for the principle proof was revised. As the results of the examination of a basic specification of the magnet used for the fusion reactor, it was understood that the resistance of tens of μ Ω or more was necessary for the resistance between turns of the magnet to reduce the heat generation during the excitation within the conventional refrigerating power. It means that the resistance only by stainless steels is too small for it. If the resistance is too large oppositely, the shut-off voltage exceeds the allowable value. Therefore, we need the conductive material that has 1, 000 to 100, 0000 times higher resistivity than stainless steels. Such a material was investigated, and conductive ceramics and the conductive resin were made candidates. Although the conductive ceramics can be a candidate for the real magnet, the conductive resin with carbon is selected for the sample from a viewpoint of productivity and easiness of obtaining. A coil sample without the layer-to-layer insulation was produced with the resin.Since the larger magnetic energy is preferred to prove the quench protection, the solenoid coil with the diameter of about 100mm was selected. The NbTi strands class 200 A in a rectangular section was used. Its copper ratio is three. The coil is pool-cooled, and its winding is insulated from surrounding helium to evaluate the temperature rise when shut-off. Then the bobbin is made of fiber reinforced plastics, and the outside of the winding is wrapped with Kapton tapes. The resistance between layers can be controlled by adjusting the spaces between the bare NbTi strands and by rubbing the conductive resin into the space. Although the winding method to secure the certain space between layers should be improved, the feasibility of the conductive resin was proved.

首先，提出了将支撑结构用作保护电阻的超导磁体的概念设计。其次，对原理验证用小线圈样品的设计进行了修正。作为用于聚变反应堆的磁体的基本规格的检查结果，可以理解，对于磁体的匝之间的电阻，数十μ Ω或更大的电阻是必要的，以减少在常规制冷功率内的激励期间的热生成。这意味着单用不锈钢的电阻太小，反之，如果电阻太大，则关断电压超过允许值。因此，我们需要电阻率比不锈钢高1000到100000倍的导电材料。对这种材料进行了研究，并将导电陶瓷和导电树脂作为候选材料。虽然导电陶瓷可以作为真实的磁体的候选物，但是从生产率和容易获得的角度考虑，选择含碳的导电树脂作为样品。用该树脂制作了无层间绝缘的线圈样品，由于更大的磁能是优选的，以证明失超保护，因此选择了直径约为100mm的螺线管线圈。使用矩形截面的NbTi股线200 A级。它的铜比是3。线圈是池冷却的，其绕组与周围的氦气绝缘，以评估关闭时的温升。然后线轴由纤维增强塑料制成，绕组外部包裹有Kapton胶带。层间电阻可以通过调整裸NbTi股线之间的间隔和通过将导电树脂摩擦到该间隔中来控制。虽然缠绕方法需要改进以确保层与层之间的一定空间，但证明了导电树脂的可行性。