本文へジャンプ

成果報告書詳細
管理番号20180000000172
タイトル*平成29年度中間年報 高温超電導実用化促進技術開発 高磁場マグネットシステム開発 高温超電導高安定磁場マグネットシステム技術開発(三菱電機株式会社)
公開日2018/6/26
報告書年度2017 - 2017
委託先名三菱電機株式会社
プロジェクト番号P16006
部署名省エネルギー部
和文要約
英文要約Title:Fundamental Commercialization Promote Technological Development of the High Temperature Superconducting. Development of High Magnetic Field Magnet System. Development of High Stable Magnetic Field HTS Magnet System Technology. (FY2016-FY2020)FY2016 Annual Report

1) The commercial technological development of HTS coils
We manufactured the pancake coils constructing a half-size 3T coil with active shielding coil sequentially in FY2016. Manufacturing shielding coils, whose outer diameter was 1.2 m, was started in FY2017. Winding accuracy of the shielding coil was about 0.1 mm just like the main coil. Yield rate was derived from the current-carrying test in single pancake coils. Yield rate in FY2017, which was less than 90 %, decreased as compared with FY2016. In order to specify degraded region in a coil, we made the device to evaluate characteristic of a coil and succeeded measuring degraded region in a coil without flowing current. HTS test coil, whose magnetic field could measure using NMR probe to evaluate effects on magnetic stability and homogeneity caused by the magnetization in HTS wire, was manufactured. We could measure the magnetic field without shimming using NMR probe and it was confirmed that we could evaluate magnetic field at the ppm level. The analysis of magnetic field and screening current in the coil was started. After this, we will align the experimental result and analysis result. Those results will be reflected to the analysis of a full-scale coil.

2) The optimization technological development of HTS magnet system
In order to reduce the size and weight of a whole-body 3T MRI magnet to a present 1.5T MRI magnet, improvement of current density and magnetic field endurance characteristics in a coil is required. To demonstrate high current density and magnetic field endurance characteristics in coil, a half-size 5T HTS coil with active shielding coil was designed. The current density in coil was set to 200 A/mm2 and the maximum experience magnetic field in coil was set to 7 T. The magnetic homogeneity was under 2ppm / 250 mmDSV, which was the same as a half-size 3T HTS coil. The cryostat of a half-size 3T HTS coil was designed. It had the solid-state thermal switches made of CFRP between 1st stage and 2nd stage in Gifford-McMahon refrigerator for shortening an initial cooling time of the coil whose weight was about 1 ton. We verified that the feedforward magnetic control, which was controlling coil current by predicting magnetic field fluctuation caused by flux creep in HTS wire, was applied for MRI magnet. It was demonstrated that the rate of magnetic field fluctuation improved drastically by using feedforward magnetic control.

3) The development of coil protection and burnout measures methods
In order to investigate the protection method of HTS coil on driven mode, the maximum allowance heating value of the small model coil, whose diameter was 90 mm, was measured in thermal insulation and liquid nitrogen cooling. As the result, it was revealed that stabilized copper in HTS wire and cooling condition around the coil affected stability, voltage with coil burning and the maximum allowance heating value.
ダウンロード成果報告書データベース(ユーザ登録必須)から、ダウンロードしてください。

▲トップに戻る