The insulation structure of the 1 MV transmission line for the ITER neutral beam injector

A. De Lorenzi, L. Grando, R. Gobbo, G. Pesavento, P. Bettini, R. Specogna, F. Trevisan

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The paper describes the studies and the tests for the development of the insulation structure of the 1 MV-50 A gas insulated (SF6) line of the ITER NBI in the SinGap configuration characterized by two kinds of spacers: at least a couple of disk-shaped spacers, designed to be gas tight, and a larger number (several tens) of inner conductor post spacers. To this aim a test campaign has been carried out to assess the capability of standard epoxy spacers to withstand a high dc voltage with frequent short circuits, simulating the operational condition for the ITER NBI. Two computational tools, the first for the epoxy spacer shape optimization under electrostatic distribution and the other for the nonlinear time variant evolution of the electric field and surface charge, have been developed specifically for designing epoxy spacer under dc voltage stress. The results on the optimization of the disk spacer and on the electric field-surface charge time evolution of the post spacer are reported and discussed. The effects of the SF6radiation induced conductivity on the post spacer are also reported. © 2007 Elsevier B.V. All rights reserved.
Original languageEnglish
Pages (from-to)836 - 844
Number of pages9
JournalFusion Engineering and Design
Issue number5-14
Publication statusPublished - Oct 2007
Externally publishedYes


All Science Journal Classification (ASJC) codes

  • Civil and Structural Engineering
  • Materials Science(all)
  • Nuclear Energy and Engineering
  • Mechanical Engineering

Cite this

De Lorenzi, A., Grando, L., Gobbo, R., Pesavento, G., Bettini, P., Specogna, R., & Trevisan, F. (2007). The insulation structure of the 1 MV transmission line for the ITER neutral beam injector. Fusion Engineering and Design, 82(5-14), 836 - 844.