The cryogenic diffusion pump and its implementation in a complete fusion reactor forevacuum system
A cryogenic diffusion pump has been developed and tested. It uses the main constituent of the fusion reactor exhaust gas, i.e. D-T, as a working fluid in a diffusion pump operating at low temperature, to separate and compress the minor constituent 3He. A prototype was tested using mixtures of deuterium with 1%, 2% and 4% helium. As the deuterium is pumped by cryocondensation at 4K, the entrained helium stays in the gas phase, is compressed and leaves the pump outlet at pressures up to 80% of the total inlet pressure. Compression ratios of up to 80 (for 1% helium) and inlet pumping speeds ranging from 1 to 2m3/s for operating pressures between 3 and 10 Pa have been measured. Deuterium carry-over into the helium exhaust is below the detection limit of the equipment. A design is presented incorporating the cryogenic diffusion pump in a complete fusion reactor fore-vacuum system, including the separation of impurities from hydrogen isotope mixtures.
Bibliographic Reference: Report: JET-P(89)43 EN (1989)
Availability: Available from the Publications Officer, JET Joint Undertaking, Abingdon, Oxon. OX14 3EA (GB)
Record Number: 199010652 / Last updated on: 1994-12-01
Original language: en
Available languages: en