Tritium transport, influx, and helium ash measurements on TFTR during DT operation

Conference · Thu Dec 01 00:00:00 EST 1994

OSTI ID:10103807

Efthimion, P C; Johnson, L C; Skinner, C H ^[1]

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1. Princeton Univ., NJ (United States). Plasma Physics Lab.; and others

The evolution of the tritium density profile is inferred from 14.1 MeV t(d,n){alpha} and 2.5 MeV d(d,n){sup 3}He neutron emissivity profiles measured in a deuterium neutral beam heated plasma into which a small amount of tritium gas has been puffed. For the first time, hydrogenic ion transport coefficients in the form of a diffusivity and convective velocity are determined. The particle diffusivities of tritium and {sup 4}He, and the deuterium thermal diffusivity are of similar magnitudes, and thus are consistent with theoretically calculated ExB drift transport. The first measurements of helium ash have been made using charge exchange recombination spectroscopy (CHERS). The measured radial ash profile shape is consistent with that predicted from simulations that include calculations of the central alpha ash source and thermal ash transport. This suggests that ash transport in the plasma core will not be a fundamental limiting factor in determining helium exhaust rates in a reactor. The authors also report the first spectroscopic measurements of tritium Balmer-alpha emission which provided a measure of tritium influx from the limiter. Tritium influx persists in discharges subsequent to tritium neutral beam injection, decaying with an initial decay of 7.5 discharges, and followed by a long term decay on the order of 400 discharges. Tritium transport, influx, and helium ash transport are important issues concerning profile control, retention, and ash removal for future reactors, like ITER.

• Research Organization: Los Alamos National Lab., NM (United States)
• Sponsoring Organization: USDOE, Washington, DC (United States)
• DOE Contract Number: W-7405-ENG-36; AC02-76CH03073
• OSTI ID: 10103807
• Report Number(s): LA-UR-94-3664; PPPL-3083; IAEA-CN-60/A-2-II-6; CONF-940933-18; ON: DE95003708; TRN: AHC29502%%127
• Resource Relation: Conference: 15. international conference on plasma physics and controlled nuclear fusion research,Madrid (Spain),26 Sep - 1 Oct 1994; Other Information: PBD: [1994]
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
TFTR TOKAMAK
OPERATION
CHARGED-PARTICLE TRANSPORT
HELIUM ASH
TRITIUM
PLASMA DRIFT
ION DENSITY
BALMER LINES
PERFORMANCE
THERMONUCLEAR REACTOR FUELING
PLASMA DENSITY
REMOVAL
DESIGN
ITER TOKAMAK
PLASMA DIAGNOSTICS
700330
700412
PLASMA KINETICS, TRANSPORT, AND IMPURITIES
MAGNETIC CONFINEMENT DEVICES