Tests of the cryogenic target for lithium and hydrogen isotopes extraction from the chamber of T-11M tokamak without its venting

• Published in: Fusion engineering and design 2014-12, Vol.89 (12), p.2923-2929
• Main Authors: Mirnov, Sergey V., Djigailo, Nadejda T., Dzhurik, Sergey P., Kostina, Anastasiya N., Kravchuk, Sergey I., Lazarev, Vladimir B., Lyublinski, Igor E., Nesterenko, Vladislav M., Petrov, Yuri V., Vertkov, Aleksei V., Zharkov, Mikhail Yu
• Format: Article
• Language: English
• Subjects: Chambers; Conditioning; Cryogenic target; Equivalence; Extraction; Lithium; Tokamak; Tokamak devices; Tritium; Walls
• ISSN: 0920-3796; 1873-7196
• DOI: 10.1016/j.fusengdes.2014.07.021

•We tested the cryogenic target as pump of Li ions sputtered from tokamak chamber by glow discharge.•We found a positive effect on the Li collection an addition of the residual gases to glow discharge.•Cooled target can be used during plasma operation to collect and remove Li and H from tokamak chamber. T-11M lithium program is focused on a solution of technological issues of a steady-state tokamak with liquid lithium plasma facing components (PFC). Lithium, collected by the chamber wall of such tokamak is able to capture a considerable amount of tritium, which is unacceptable. In order to restrict the level of lithium deposited on the chamber wall and captured tritium it was suggested early to use a cryogenic target technique. Such target placed in the plasma of glow discharge (GDH, He or Ar) during the tokamak conditioning can play the role of collector of lithium and tritium atoms which were sputtered by GD bombardment of the wall. The collected lithium and tritium can be evacuated mechanically together with target from tokamak chamber through vacuum lock without venting. Cryogenic target, cooled by liquid nitrogen (LN), was installed in the T-11M and tested in different modes of wall conditioning and tokamak operations. The maximum speed of the lithium collection during GDH was 3.5mg/h, that corresponds “to contamination” of wall by lithium during approximately 200 regular shots of T-11M which are equivalent to two-week regular operations. It was established that considerable part of lithium was collected in ionized state. On this basis it can be suggested the creation in tokamak chamber an equivalent ionic pump for extraction both lithium and tritium from chamber without venting during regular tokamak operation.