Effects of wall boron coating on FTU, an all metallic and carbon free medium size tokamak

M.L. Apicella, G. Mazzitelli, B. Esposito, L. Gabellieri, M. Leigheb, V. Pericoli Ridolfini, L. Pieroni, M. Romanelli, R. Zagórski

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Boronization of FTU tokamak strongly affects its gas recycling, impurity concentration and its temporal evolution. Two main phases are distinguished. In the first one, lasting about 60 discharges, with the machine fully boronized, the radiation losses decrease from 80% to 40% and the impurity content drops from Zeff ≤ 6 to Zeff ≈ 1.5 at in ohmic conditions. In the second phase, lasting >500 discharges, with the B film eroded from the TZM toroidal limiter surface but not from the SS walls, the reduction of radiated power (≈60%) and impurities (Zeff ≈ 2.0) though smaller, is still important with respect to pre-boronization, allowing for optimization of plasma characteristics up to the maximum RF power so far injected (2.6 MW ≈ 1.6 MW m-3). The recycling properties of the B film are fully stabilized, making the plasma operations much more reliable, while the gettering properties are preserved and they maintain the oxygen below nO ≤ 0.5%. © 2005 IAEA, Vienna.
Original languageEnglish
Pages (from-to)685 - 693
Number of pages9
JournalNuclear Fusion
Issue number7
Publication statusPublished - 1 Jul 2005
Externally publishedYes


All Science Journal Classification (ASJC) codes

  • Physics and Astronomy(all)
  • Condensed Matter Physics
  • Nuclear and High Energy Physics

Cite this

Apicella, M. L., Mazzitelli, G., Esposito, B., Gabellieri, L., Leigheb, M., Ridolfini, V. P., ... Zagórski, R. (2005). Effects of wall boron coating on FTU, an all metallic and carbon free medium size tokamak. Nuclear Fusion, 45(7), 685 - 693. https://doi.org/10.1088/0029-5515/45/7/018