Thermo-mechanical design of the ITER neutral beam injector grids for radio frequency ion source and SINGAP accelerator

P. Agostinetti, S. Dal Bello, M. Dalla Palma, D. Marcuzzi, P. Zaccaria, R. Nocentini, M. Fröschle, B. Heinemann, R. Riedl

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Abstract

This paper focuses on the thermo-mechanical design of the ITER Neutral Beam Injector plasma, extraction and acceleration grids, considering the Radio Frequency option for the negative ion source and the SINGAP option for the accelerator. The SINGle Aperture - SINgle GAP (SINGAP) accelerator for ITER NBI foresees four grids for the extraction and acceleration of negative ions, instead of the seven grids of the Multi Aperture Multi Grid (MAMuG) reference configuration. The Radio Frequency ion source is a promising alternative to the Arc Driven one, showing very good performances in recent experiments at IPP Garching (D) and having the advantage of reduced maintenance requirements. A specific plasma grid was designed for RF source considering lower heat loads and different operational requirements. In particular the thermohydraulic and thermo-mechanical design aims at having all over the plasma grid a precisely controlled temperature to enhance the negative ions yield inside the caesium seeded source. Analytical and numerical (FE) thermo-mechanical analyses were also carried out for the extraction and acceleration grids. Structural verifications were accomplished according to the ITER Structural Design Criteria for In-Vessel Components. Design optimizations were performed in order to limit the misalignment of the grids within the tolerance specified by beam optics requirements (0.4 mm of maximum misalignment between corresponding apertures axes). The optimum cooling parameters under different operational scenarios were identified. The paper describes the design status of the grid system for the RF ion source and discusses in detail the numerical work carried out for thermo-mechanical and fluid dynamic behaviour. ©2007 IEEE.
Original languageEnglish
DOIs
Publication statusPublished - 2007
Externally publishedYes
Event22nd IEEE/NPSS Symposium on Fusion Engineering - SOFE 07 - , United States
Duration: 1 Jan 2007 → …

Conference

Conference22nd IEEE/NPSS Symposium on Fusion Engineering - SOFE 07
CountryUnited States
Period1/1/07 → …

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All Science Journal Classification (ASJC) codes

  • Nuclear and High Energy Physics
  • Nuclear Energy and Engineering

Cite this

Agostinetti, P., Dal Bello, S., Dalla Palma, M., Marcuzzi, D., Zaccaria, P., Nocentini, R., Fröschle, M., Heinemann, B., & Riedl, R. (2007). Thermo-mechanical design of the ITER neutral beam injector grids for radio frequency ion source and SINGAP accelerator. Paper presented at 22nd IEEE/NPSS Symposium on Fusion Engineering - SOFE 07, United States. https://doi.org/10.1109/FUSION.2007.4337905