In situ spectroscopic measurements of erosion behavior of TFTR-redeposited carbon materials under high-flux plasma bombardment in PISCES-A
The chemical erosion behavior of graphite materials pre-exposed in Tokamak Fusion Test Reactor (TFTR) as the bumper limiter has been investigated spectroscopically under deuterium plasma bombardment in the PISCES-A facility. The deuterium plasma bombardment conditions are: ion bombarding energy of 300 eV; ion flux of 1.7 /times/ 10/sup 18/ ions s/sup /minus/1/ cm/sup /minus/2/; plasma density of 1.4 /times/ 10/sup 12/ cm/sup /minus/3/; electron temperature of 11 eV; and neutral pressure of 3 /times/ 10/sup /minus/4/ torr. The chemical erosion yield is measured with CD-band spectroscopy during the temperature ramp from 100 to 900/degree/C at an average rate of about 5 degrees/s. The materials used include virgin POCO AFX-5Q graphite, graphite tile pieces from the redeposition-dominated and erosion-dominated areas of the bumper limiter in TFTR. It has been found in common for these graphite materials that the chemical erosion yield maximizes at a temperature around 550/degree/C. However, graphite from the redeposited area has shown a somewhat higher maximum erosion yield and significantly steeper temperature dependence. In addition, the removability of the redeposited materials by helium plasma bombardment has been studied. The removal rate is found to be similar to the physical sputtering yield of carbon by helium. The surface morphology and surface composition has been analyzed with SEM and EMPA in parallel with these erosion behavior measurements. 38 refs., 5 figs., 1 tab.
- Research Organization:
- California Univ., Los Angeles (USA). Inst. for Plasma and Fusion Research
- DOE Contract Number:
- AS03-84ER52104
- OSTI ID:
- 6821445
- Report Number(s):
- UCLA/PPG-1174; CONF-881002-5; ON: DE88017229; TRN: 88-035406
- Resource Relation:
- Conference: 35. national vacuum symposium and 4th international laser science conference, Atlanta, GA, USA, 2 Oct 1988; Other Information: Portions of this document are illegible in microfiche products
- Country of Publication:
- United States
- Language:
- English
Similar Records
In situ spectroscopic measurements of erosion behavior of Tokamak Fusion Test Reactor redeposited carbon materials under high-flux plasma bombardment in Plasma Interactive Surface Component Experimental Station-A
Erosion and redeposition behavior of selected net-candidate materials under high-flux hydrogen, deuterium plasma bombardment in PISCES
Related Subjects
THERMONUCLEAR REACTOR MATERIALS
EROSION
CALIBRATION
GRAPHITE
LIMITERS
MEASURING METHODS
SCANNING ELECTRON MICROSCOPY
SPECTRA
SPUTTERING
TFTR TOKAMAK
CARBON
ELECTRON MICROSCOPY
ELEMENTAL MINERALS
ELEMENTS
MATERIALS
MICROSCOPY
MINERALS
NONMETALS
THERMONUCLEAR REACTORS
TOKAMAK TYPE REACTORS
700209* - Fusion Power Plant Technology- Component Development & Materials Testing