LARGE-SCALE TESTS OF INSULATED CONDUIT FOR THE ITER CS COIL

Compression-fatigue tests at 77 K were conducted on test modules of in sulated Incoloy 908 conduit. To replicate the operating conditions for the ITER central solenoid (CS) full-scale coil, fatigue loads up to 3 .6 MN were applied for 10(5) cycles; no mechanical breakdowns occurred . The conduits were insulated with a preimpregnated resin system, a te traglycidyl diaminodiphenyl methane (TGDM) epoxy cured with DDS aromat ic amine. The conduits were joined by vacuum-pressure impregnation wit h a diglycidyl ether of bisphenol-F epoxy/anhydride-cured resin system . In the 4 x 4 stacked-conduit test modules, the layer insulation (a h igh-pressure laminate of TGDM epoxy cured with DDS aromatic amine) was inserted. Periodically during the tests, breakdown voltage was measur ed across the conduits of both turn and layer insulation; throughout t he test, breakdown voltages were at least 46 kV. The addition of a bar rier increased structural and electrical reliability. (C) 1998 Elsevie r Science Ltd. All rights reserved.