Experimental results from a beam direct converter at 100 kV

Journal Article · Thu Apr 01 04:00:00 EST 1982 · J. Fusion Energy; (United States)

DOI:https://doi.org/10.1007/BF01054580· OSTI ID:5490268

Barr, W L; Hamilton, G W; Moir, R W

A direct-energy converter was developed for use on neutral-beam injectors. The purpose of the converter is to raise the efficiency of the injector by recovering the portion of the ion beam not converted to neutrals. In addition to increasing the power efficiency, direct conversion reduces the requirements on power supplies and eases the beam dump problem. The converter was tested at Lawrence Berkeley Laboratory on a reduced-area version of a neutral-beam injector developed for use on the Tokamak Fusion Test Reactor at Princeton. The conversion efficiency of the total ion power was 65 + or - 7% at the beginning of the pulse, decaying to just over 50% by the end of the 0.6-s pulse. Once the electrode surfaces were conditioned, the decay was due to the rise in pressure of only the beam gas and not to outgassing. The direct converter was tested with 1.7 A of hydrogen ions and with 1.5 A of helium ions through the aperture with similar efficiencies. At the midplane through the beam, the line power density was 0.7 MW/m, for comparison with our calculations of slab beams and the prediction of 2-4 MW/m in some reactor studies. Over 98 kV was developed at the ion collector when the beam energy was 100 keV. New electrode material released gas (mostly H/sub 2/ and CO) in amounts that exceeded the input of primary gas from the beam. The electrodes were all made of 0.51-mm-thick molybdenum cooled only by radiation. This allowed the heating by the beam to outgas the electrodes and for them to stay hot enough to avoid the reabsorption of gas between shots. By minor redesign of the electrodes, adding cryopanels near the electrodes, and grounding the ion source, these results extrapolate with high confidence to an efficiency of 70-80% at a power density of 2-4 MW/m.

• Research Organization: Lawrence Livermore Laboratory, Livermore, California
• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 5490268
• Journal Information: J. Fusion Energy; (United States), Journal Name: J. Fusion Energy; (United States) Vol. 2:2; ISSN JFEND
• Country of Publication: United States
• Language: English

Related Subjects

30 DIRECT ENERGY CONVERSION
300800* -- Direct Energy Conversion-- Miscellaneous Converters
70 PLASMA PHYSICS AND FUSION TECHNOLOGY
700203 -- Fusion Power Plant Technology-- Power Supplies
Energy Storage
700205 -- Fusion Power Plant Technology-- Fuel
Heating
& Injection Systems
BEAM INJECTION
BEAM INJECTION HEATING
BEAMS
BETA DECAY
CONVERSION
DECAY
DESIGN
DIRECT COLLECTION CONVERTERS
DIRECT ENERGY CONVERSION
DIRECT ENERGY CONVERTERS
EFFICIENCY
ELECTRODES
ENERGY CONVERSION
ENERGY RANGE
ENERGY RECOVERY
HEATING
ION BEAMS
KEV RANGE
KEV RANGE 10-100
MHD GENERATORS
NEUTRAL ATOM BEAM INJECTION
NEUTRAL BEAM SOURCES
PERFORMANCE
PLASMA HEATING
RECOVERY
THERMONUCLEAR REACTORS
TOKAMAK TYPE REACTORS