DocumentCode :
67597
Title :
Testing of the Ceramic Insulation Break for Fusion Device
Author :
Huajun Liu ; Qingyun Qu ; Qinyan Pan ; Yu Wu ; Chuanjun Huang ; Laifeng Li ; Min Yu ; Liang Guo
Author_Institution :
Inst. of Plasma Phys., Hefei, China
Volume :
24
Issue :
3
fYear :
2014
fDate :
Jun-14
Firstpage :
1
Lastpage :
4
Abstract :
Large magnet system is an essential component of most current or planned fusion devices. Axial insulation breaks are required in order to electrically isolate the cryogenic distribution system from the potential high voltage of the magnet system and bus bars. The epoxy resin based insulation break could be the weak link in magnet design, due to insulation sensitivity to high irradiation doses. The Al2O3 ceramic material instead of epoxy based material was used to manufacture the insulation break. Kovar alloy which has a similar mean coefficient of thermal expansion with Al2O3 ceramic in the temperature range of 300-1073 K was used as two ends of the insulation breaks. The ceramic tubes and Kovar alloy tubes were vacuum brazed together using silver-based filler at 1073 K. The helium tightness, the insulation resistances and dielectric breakdown were checked at room temperature and LN2 temperature. Then 2 kN traction and compression were tested at room temperature and LN2 temperature. The maximum tensile force of 8.62 kN and 8.18 kN were measured at room temperature and LN2 temperature, respectively. The three point bending test was carried out. The test results of 4.5 kN and 3.6 kN were measured at room temperature and LN2 temperature, respectively. The 50 thermal shock cycles were performed from 77 K to 300 K to ensure that the ceramic break could operate under rapid temperature change.
Keywords :
alumina; bending; ceramics; electric breakdown; electric resistance; mechanical testing; superconducting magnets; thermal shock; Al2O3; Kovar alloy tubes; alumina ceramic material; axial insulation breaks; bus bars; ceramic insulation break testing; ceramic tubes; cryogenic distribution system; dielectric breakdown; epoxy based material; epoxy resin based insulation break; fusion device component; helium tightness; insulation resistances; insulation sensitivity; irradiation doses; magnet design; magnet system voltage; silver-based filler; temperature 77 K to 1073 K; thermal expansion coefficient; Ceramics; Electron tubes; Metals; Temperature distribution; Temperature measurement; Ceramic; Kovar alloy; insulation break; mechanical test;
fLanguage :
English
Journal_Title :
Applied Superconductivity, IEEE Transactions on
Publisher :
ieee
ISSN :
1051-8223
Type :
jour
DOI :
10.1109/TASC.2013.2287278
Filename :
6648389
Link To Document :
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