The TEXTOR helium self-pumping experiment : Design, plans and supporting ion-beam data on helium retention in nickel
A proof-of-principle experiment to demonstrate helium self-pumping in a tokamak is being undertaken in TEXTOR. The experiment will use a helium self-pumping module installed in a modified ALT-I limiter head. The module consists of two, approximately 25x25 cm2 heated nickel alloy trapping plates, a nickel deposition filament array and associated diagnostics. Between plasma shots a coating of approximately 50 Angstroms nickel will be deposited on the two trapping plates. During a shot, helium and hydrogen ions will impinge on the plates through an approximately 3 cm wide entrance slot. The helium removal capability, due to trapping in the nickel, will be assessed for a variety of plasma conditions. In support of the tokamak experiment, the trapping of helium over a range of ion fluences and surface temperatures, and detrapping during subsequent exposure to hydrogen, were measured in ion beam experiments using evaporated nickel surfaces similar to those expected in TEXTOR. The retention of H and He after exposure of a nickel surface to mixed He/H plasmas was also measured. The results appear favourable, showing high helium trapping (approximately 10-50% He/Ni) and little or no detrapping by hydrogen. The TEXTOR experiment is to begin in 1991.
Bibliographic Reference: Article: Journal of Nuclear Materials, Vol. 176 & 177 (1990) pp. 635-639
Record Number: 199110648 / Last updated on: 1994-12-02
Original language: en
Available languages: en