RT Journal Article
T1 Characterization of low temperature high voltage axial insulator breaks for the ITER cryogenic supply line
A1 Fernández Pisón, María del Pilar
A1 Sgobba, Stefano
A1 Avilés Santillana, Ignacio
A1 Langeslag, S.A.E
A1 Su, M.
A1 Piccin, R.
A1 Journeaux, J.Y.
A1 Laurenti, A.
A1 Pan, W.
AB Cable-in-conduit conductors of the ITER magnet system are directly cooled by supercritical helium. Insulation breaks are required in the liquid helium feed pipes to isolate the high voltage system of the magnet windings from the electrically grounded helium coolant supply line. They are submitted to high voltages and significant internal helium pressure and will experience mechanical forces resulting from differential thermal contraction and electro-mechanical loads. Insulation breaks consist essentially of stainless steel tubes overwrapped by an outer glass - fiber reinforced composite and bonded to an inner composite tube at each end of the stainless steel fittings. For some types of insulator breaks Glass - Kapton - Glass insulation layers are interleaved in the outer composite. Following an extensive mechanical testing campaign at cryogenic temperature combined with leak tightness tests, the present paper investigates through non-destructive and destructive techniques the physical and microstructural characteristics of the low temperature high voltage insulation breaks and of their individual components, thus allowing to correlate the structure and properties of the constituents to their overall performance. For all the tests performed, consistent and reproducible results were obtained within the range of the strict acceptance criteria defined for safe operation of the insulation breaks.
PB IOP Publishing Limited
SN 1757-8981
YR 2017
FD 2017-07-09
LK https://hdl.handle.net/10016/38514
UL https://hdl.handle.net/10016/38514
LA eng
NO Proceedings of the International Cryogenic Materials Conference (ICMC) 2017 (previous edition: ICMC-2015) 9–13 July 2017, Madison, Wisconsin, USA
NO The cryogenic cycling, mechanical and electrical measurements and leak tightness tests were carried out by the Magnet Infrastructure Facilities for ITER (MIFI) under the supervision of the ITER Organization; Tg was measured by A. Rivière at the chemistry laboratory of CERN (TE/VSC/SCC); PT was performed by A.M. Piguiet, a level 2 certified operator (COFREND ID n° 012084) of the Materials and Metrology section of CERN (EN/MME/MM).
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RD 18 jul. 2024