Impurity and particle transport and control in TFTR

Technical Report · Wed Apr 01 04:00:00 EST 1987

DOI:https://doi.org/10.2172/6400030· OSTI ID:6400030

Hill, K W; Arunasalam, V; Bell, M G; Bitter, M; Blanchard, W R; Bretz, N L; Budny, R; Bush, C E; Cohen, S A; Combs, S K

Degassing of the TFTR graphite limiter by low density deuterium or helium discharges enables the limiter to pump deuterium, thereby reducing recycling and improving energy confinement in neutral-beam-heated discharges. During a helium degassing sequence the hydrogen influx decreased by a factor of 20. As a consequence of degassing sequences the low density limit in 0.8 mA deuterium discharges decreased from 1 x 10/sup 19/ m/sup -3/ to 0.5 x 10/sup 19/ m/sup -3/, the density-decay time dropped from greater than 10 s to 0.15 s, and the recycling coefficient dropped from nearly 1 to less than 0.4. Z/sub eff/ values in 2.2 MA L-mode discharges on the toroidal limiter with neutral-beam-heating power up to 15 MW are between 2 and 3 if the pre-beam plasma has low Z/sub eff/ (high density), but can be as high as 4.5 if the pre-beam target has high Z/sub eff/ (low density). Z/sub eff/ values in enhanced confinement shots drop from 7 during the ohmic phase to 3 with neutral beam heating. The radiated power drops from 60 to 70% of total heating power to 30 to 35% for beam powers from 10 to 20 MW.

• Research Organization: Princeton Univ., NJ (USA). Plasma Physics Lab.
• DOE Contract Number: AC02-76CH03073
• OSTI ID: 6400030
• Report Number(s): PPPL-2421; ON: DE87010631
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
700205* -- Fusion Power Plant Technology-- Fuel
Heating
& Injection Systems
BEAM INJECTION
CONFINEMENT
DEGASSING
DEUTERIUM
ELEMENTS
FLUIDS
GASES
HELIUM
HYDROGEN ISOTOPES
ISOTOPES
LIGHT NUCLEI
LIMITERS
NEUTRAL ATOM BEAM INJECTION
NONMETALS
NUCLEI
ODD-ODD NUCLEI
PLASMA CONFINEMENT
RARE GASES
STABLE ISOTOPES
TFTR TOKAMAK
THERMONUCLEAR REACTORS
TOKAMAK TYPE REACTORS