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Abstract

When Tokamaks are vented, as is inevitable for repair and modification work, graphite components should adsorb as little gas as possible. This reduces the risk of uncontrolled gas desorption in Tokamak operation. The purpose of this investigation is to determine whether various types of graphite differ with respect to gas adsorption and whether a low-Z coating with pyrocarbon or silicon carbide might possibly significantly reduce gas uptake. The investigation was concerned with the gas release of samples in the state in which they were delivered by various manufacturers and with the subsequent gas uptake when they were exposed to air after degassing. There were no drastic differences between the graphites investigated. Pyrocarbon coating does not reduce the short-time gas adsorption within 1-2 days, slows down further gas adsorption by a factor of up to 10 in one case, and not at all in another case. The cause of these big differences has not been clarified. Coating with SiC has just a small influence on gas adsorption. Mass spectrometric investigation of the desorbed gas shows appreciable differences in gas composition and desorption temperature with about equal weight loss. The causes of these differences are not known either.

Additional information

Authors: VERNICKEL H, MAX-PLANCK-INSTITUT FUER PLASMAPHYSIK, GARCHING BEI MUENCHEN (GERMANY);BOHDANSKY J, MAX-PLANCK-INSTITUT FUER PLASMAPHYSIK, GARCHING BEI MUENCHEN (GERMANY);KUTSCH H J, MAX-PLANCK-INSTITUT FUER PLASMAPHYSIK, GARCHING BEI MUENCHEN (GERMANY);OTTENBERGER W, MAX-PLANCK-INSTITUT FUER PLASMAPHYSIK, GARCHING BEI MUENCHEN (GERMANY);ROTH J, MAX-PLANCK-INSTITUT FUER PLASMAPHYSIK, GARCHING BEI MUENCHEN (GERMANY);SCHERZER R, MAX-PLANCK-INSTITUT FUER PLASMAPHYSIK, GARCHING BEI MUENCHEN (GERMANY);STEINBERGER F, MAX-PLANCK-INSTITUT FUER PLASMAPHYSIK, GARCHING BEI MUENCHEN (GERMANY);TRCKA E MAX-PLANCK-INSTITUT FUER PLASMAPHYSIK, GARCHING BEI MUENCHEN (GERMANY), MAX-PLANCK-INSTITUT FUER PLASMAPHYSIK, GARCHING BEI MUENCHEN (GERMANY)
Bibliographic Reference: WRITE TO MAX-PLANCK-INSTITUT FUER PLASMAPHYSIK, 8046 GARCHING BEI MUENCHEN (GERMANY), MENTIONING REPORT IPP 1/239, 1987
Record Number: 1989126019200 / Last updated on: 1989-03-01
Category: PUBLICATION
Available languages: en