Thermo-Oxidation of Tokamak Carbon Dust
The oxidation of dust and flakes collected from the DIII-D tokamak, and various commercial dust specimens, has been measured at 350 ºC and 2.0 kPa O2 pressure. Following an initial small mass loss, most of the commercial dust specimens showed very little effect due to O2 exposure. Similarly, dust collected from underneath DIII-D tiles, which is thought to comprise largely Grafoil™ particulates, also showed little susceptibility to oxidation at this temperature. However, oxidation of the dust collected from tile surfaces has led to ~ 18% mass loss after 8 hours; thereafter, little change in mass was observed. This suggests that the surface dust includes some components of different composition and/or structure – possibly fragments of codeposited layers. The oxidation of codeposit flakes scraped form DIII-D upper divertor tiles showed an initial 25% loss in mass due to heating in vacuum, and the gradual loss of 30-38% mass during the subsequent 24 hours exposure to O2. This behavior is significantly different from that observed for the oxidation of thinner DIII-D codeposit specimens which were still adhered to tile surfaces, and this is thought to be related to the low deuterium content (D/C ~ 0.03 – 0.04) of the flakes.
- Research Organization:
- Idaho National Lab. (INL), Idaho Falls, ID (United States)
- Sponsoring Organization:
- DOE - SC
- DOE Contract Number:
- DE-AC07-99ID-13727
- OSTI ID:
- 927636
- Report Number(s):
- INL/CON-08-13664; TRN: US0804806
- Resource Relation:
- Conference: 13th International Conference on Fusion Reactor Materials,Nice, France,12/10/2007,12/14/2007
- Country of Publication:
- United States
- Language:
- English
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