On hydrogen transport and edge plasma modeling of liquid-metal divertors

Journal Article · Mon Mar 01 00:00:00 EST 1993 · Fusion Technology; (United States)

OSTI ID:6363826

Liao, Chungpin; Kazimi, M S; Meyer, J E ^[1]

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1. Massachusetts Inst. of Technology, Cambridge (United States)

The steady-state operational conditions for large tokamaks impose high performance requirements that cast suspicion on the employment of conventional solid surface divertors. Flowing liquid-metal divertors are thus being considered as an alternative. A preliminary evaluation is made of some aspects of this concept. To understand the hydrogen (i.e., deuterons and tritons) recycling behavior in liquid metals, the transport and chemistry aspects of the hydrogen/liquid-metal interaction are investigated, including hydrogen gettering, tritium inventory, and blistering caused by hydrogen bubble eruptions. It is shown that when operating in the high-recycling model (i.e., as the liquid metal is filled with deuterons and tritons, one implanting ion will immediately cause the emission of one neutral particle), lithium would have a large tritium inventory. Gallium, on the other hand, does not have the same problem because of its negligible hydrogen solubility and the decomposition of its hydrides in the temperature range of interest. However, to avoid blistering, the flow speed of a gallium neutralizer has to be high. An edge plasma simulation model is briefly introduced, and its outcome for the high-recycling liquid-metal (lithium and gallium) divertors is presented. This model gives more realistic predictions of plasma temperature than some of the existing simulation models. Results of this model show that denser and cooler edge plasmas can be achieved by liquid-metal divertors than by conventional stationary surface divertors. Evaporation and sputtering of liquid-metal divertors are shown not to be as serious a problem as might be suspected at first glance. 22 refs., 2 figs., 1 tab.

• OSTI ID: 6363826
• Journal Information: Fusion Technology; (United States), Vol. 23:2; ISSN 0748-1896
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
DIVERTORS
DESIGN
LIQUID METALS
TOKAMAK DEVICES
COMPUTERIZED SIMULATION
DEUTERONS
GALLIUM
HYDROGEN
LITHIUM
PLASMA SCRAPE-OFF LAYER
TRITIUM
ALKALI METALS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BOUNDARY LAYERS
CHARGED PARTICLES
CLOSED PLASMA DEVICES
ELEMENTS
FLUIDS
HYDROGEN ISOTOPES
ISOTOPES
LAYERS
LIGHT NUCLEI
LIQUIDS
METALS
NONMETALS
NUCLEI
ODD-EVEN NUCLEI
RADIOISOTOPES
SIMULATION
THERMONUCLEAR DEVICES
YEARS LIVING RADIOISOTOPES
700420* - Fusion Technology- Plasma-Facing Components- (1992-)