Adaptation of the 1 MV bushing to the SINGAP concept for the ITER NB injector test bed

Abstract

The 1 MV bushing of the ITER NB injector is probably one of the most challenging components of the whole accelerator, since such a high voltage (HV) in a contaminated and radiated environment requires the development of non-standard technologies. This paper intends to provide a guideline for the design of 1 MV bushing for the ITER neutral beam injector test bed. Although mainly focused on the SINGAP alternative concept of the injector, the reported general criteria can be useful for the design of other HV components, such as post insulators of the acceleration grids. For every different kind of required insulation, basic physical models describing breakdown phenomena are reported together with the main technological implications and the practical recommendations necessary to improve insulation performance. The results of the finite element analyses of 1 MV bushing, operating at CEA-Cadarache laboratories, are used to validate general criteria in a typical geometry. The effects of radiation, such as neutrons and gamma rays, on solid insulators and gases have also been taken into account, describing the most important phenomena and the related implications in terms of voltage hold-off capabilities. Finally the design of the bushing in the SINGAP option and the solutions adopted are described.

Development of 1MeV accelerator and HV bushing at JAEA toward ITER Neutral Beam system

“…Masiello proposed design criteria for electric stress in the HV bushing as summarized in Table 1 [9]. The table also shows other criteria from the EDA design, which allows rather high stress than Masiello's.…”

Design optimization of the 100 kV HV bushing for ITER-DNB

“…Further, HVB provides isolation between high voltage feedlines and grounded DNB vessel. The main purpose of HVB is therefore (i) to carry the requirements of source and accelerator like high current busbars, RF transmission lines, water cooling services, gas feed and diagnostic lines [3,4] and (ii) to form a part of primary safety barrier and vacuum confinement in ITER. DDD [5] configuration of the HVB has been taken as a baseline design.…”

Design and Overview of 100 kV Bushing for the DNB Injector of ITER

“…It carries all the electric, hydraulic and gas connections to the beam source. There are few reports published on the design, analysis and manufacturing of HNB bushing [5][6][7] for 1 MV requirements. This paper presents the design and manufacturing feasibility of the DNB bushing.…”