Lithium Operations on the Lithium Tokamak Experiment
Authors: T. Kozob, R. Majeski, R. Kaitaa, E. Granstedt, C. Jacobson, D. Lundberg and J. Timberlake
Abstract:
The lithium tokamak experiment (LTX) is a small
spherical tokamak currently operating to investigate the low
recycling regime for magnetically confined plasmas through the
utilization of liquid lithium coated plasma facing surfaces. The
LTX machine is unique in that it incorporates inside the vacuum
vessel a heated conducting shell that encloses about 80% of the
last closed flux surface of the plasma. The conforming shell
operates at temperatures up to 500oC and is coated with a thin
liquid lithium film. Two retractable crucible evaporators are used
to deposit the lithium film on the shell inner surfaces. Various
methods and procedures for lithium deposition onto the shell
surfaces have been tested by varying the component temperatures
and vessel pressure, and utilizing concurrent glow discharge.
Operating procedures and safety systems have been developed
and implemented to ensure the safe operation with lithium at
elevated temperatures. The machine has successfully operated
with lithium coated shells demonstrating improved plasma
performance as a result. Maintaining an active lithium surface
between lithium evaporations was an issue and new features are
currently being installed to address this. The machine has also
been vented and the internal surfaces cleaned without any
difficulty. Operating results, current status, ongoing upgrades
and future plans will be presented.
__________________________________________________
Submitted to: 38th International Conference on Plasma Science & 24th Symposium on Fusion Engineering/ICOPS 2011 SOFE, Chicago, IL, June 26-30, 20011
__________________________________________________
Download PPPL-4696 (pdf 1.12 MB 3 pp)
__________________________________________________