Experience with Zr-Al Getter Pumps in the ISX-B Tokamak

摘要

Zr-Al getter pumps have been used in the ISX-B tokamak in connection with a series of pump limiter experiments. Experience with these pumps in this environment has revealed several problems that may limit their usefulness under typical tokamak operating conditions. Although the pumps perform satisfactorily while in operation with hydrogenic pumping speeds of 1-2 x 10 exp 3 L/s at pressures of approx. 10 mtorr, some unknown mechanism, on occasion, slightly activates pumps that had been previously passive. Such behavior precludes the use of any operations that require high hydrogen pressures in the torus. Additionally, discharge cleaning operations cannot be safely carried out after the pumps are fully activated. Continued use of the pumps eventually leads to destruction of two getter cartridges from hydrogen embrittlement. (ERA citation 09:011265)