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
The chemical erosion behavior of graphite materials preexposed in the Tokamak Fusion Test Reactor (TFTR) as the bumper limiter has been investigated spectroscopically under deuterium plasma bombardment in the Plasma Interactive Surface Component Experimental Station-A (PISCES-A) facility. The deuterium plasma bombardment conditions are ion bombarding energy of 300 eV, ion flux of 1.7 x 10/sup 18/ ions s/sup -1/ cm/sup -2/, plasma density of 1.4 x 10/sup 12/ cm/sup -3/, electron temperature of 11 eV, and neutral pressure of 3 x 10/sup -4/ Torr. The chemical erosion yield is measured with calibrated CD-band spectroscopy during the temperature ramp from 100 to 900 /sup 0/C at an average rate of /similar to/5 K/s. The materials used include virgin POCO graphite and graphite tile pieces from the redeposited and eroded areas of the bumper limiter of TFTR. The deuterocarbon formation rate from TFTR redeposits maximizes at /similar to/500 /sup 0/C. Essentially the same chemical erosion behavior is observed for TFTR-eroded and virgin graphites and is characterized by the compound peak, indicative of two erosion yield maxima at around 575 and 700 /sup 0/C. The maximum erosion yield for TFTR redeposits is found to be /similar to/15% higher than those for TFTR-eroded and virgin POCO graphites, which is attributed to deuterium incorporated in the redeposited material. In addition, the removal behavior of redeposits by helium plasma bombardment has been studied. The removal rate is evaluated to be similar to the physical sputtering yield of carbon by helium. The surface morphology and surface composition have been analyzed with scanning electron microscopy and electron microprobe analysis along with these erosion yield measurements. behavior
- Research Organization:
- Department of Mechanical, Aerospace and Nuclear Engineering, Institute of Plasma and Fusion Research, University of California, Los Angeles, Los Angeles, California 90024
- OSTI ID:
- 6316818
- Journal Information:
- J. Vac. Sci. Technol., A; (United States), Vol. 7:3
- Country of Publication:
- United States
- Language:
- English
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In situ spectroscopic measurements of erosion behavior of TFTR-redeposited carbon materials under high-flux plasma bombardment in PISCES-A
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Related Subjects
REACTOR COMPONENTS
EROSION
TFTR TOKAMAK
IMPURITIES
DEUTERIUM
EXPERIMENTAL DATA
GRAPHITE
ION COLLISIONS
PLASMA
SURFACE TREATMENTS
TORI
CARBON
COLLISIONS
DATA
ELEMENTAL MINERALS
ELEMENTS
HYDROGEN ISOTOPES
INFORMATION
ISOTOPES
LIGHT NUCLEI
MINERALS
NONMETALS
NUCLEI
NUMERICAL DATA
ODD-ODD NUCLEI
STABLE ISOTOPES
THERMONUCLEAR REACTORS
TOKAMAK TYPE REACTORS
700209* - Fusion Power Plant Technology- Component Development & Materials Testing