DIII-D RESEARCH OPPORTUNITIES FORUM FOR THE 2013 EXPERIMENTAL CAMPAIGN Review | Direct submission with log-in | Request submission without log-in
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Title	233: C erosion and D up-take at high surface temperature
Name:	Clement Wong wongc@fusion.gat.com	Affiliation:	General Atomics
Research Area:	Plasma-material Interface	Presentation time:	Not requested
Co-Author(s):	C.P.C. Wong, D. Rudakov, P.C. Stangeby, J. Watkins, W. Wampler, D. Elder, J. Brooks, A. Chavez	ITPA Joint Experiment :	No
Description:	Compare graphite surface erosion and deuterium concentration at ambient and high surface (~700° C) temperature.	ITER IO Urgent Research Task :	No
Experimental Approach/Plan:	Two depth-marked graphite DiMES buttons will be used for the experiment. The graphite buttons will first be outgassed with minimum content of hydrogen, and the initial graphite thicknesses measured. Two DiMES button holder module will be used. The first DiMES module will be designed with the capability of heating the central button to ~800° C. The second DiMES module is a non-heated one. Partially detached H-mode plasma conditions will be used. The first part of the ½ day experiment will be exposing the heated sample to 4-5 well-characterized discharges, after which the heated DiMES module will be exchanged to the non-heated module. The second half of the ½ day experiment will be used to expose the ambient temperature module to another 4-5 well-characterized discharges. If these cannot be accomplished in one ½ day, a two ½ day experiment could be requested.
Background:	ITER will make decision on the divertor surface material for the initial phase of ITER operation by the end of 2013, between the use of W/C and all W divertor. A W/C divertor will be more tolerant to the ITER initial startup events including transient effects like ELMs and disruption. The critical potential drawback of the W/C divertor option is the high C erosion and the corresponding projected high tritium inventory in the carbon. Due to safety consideration the ITER PFC tritium inventory is limited to 0.7 kg. It is important to provide technical data on the graphite surface erosion and corresponding tritium inventory when the surface is operating at around 700° C.
Resource Requirements:	One, if necessary two ½ day experiments, partially detached LSN H-mode with OSP on DiMES.
Diagnostic Requirements:	All available lower divertor diagnostics, Langmuir probes, DiMES, core and divertor Thomson, CER with C lines. IRTV view of DiMES highly desirable.
Analysis Requirements:
Other Requirements: