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Design study of a 120-keV,3He neutral beam injector

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Abstract

We describe a design for a 120-keV, 2.3-MW,3He neutral beam injector for use on a D-3He fusion reactor. The constraint that limits operating life when injecting He is its high sputtering rate. The sputtering is partly controlled by using an extra grid to prevent ion flow from the neutralizer duct to the electron suppressor grid, but a tradeoff between beam current and operating life is still required. Hollow grid wires functioning as mercury heat pipes cool the grid and enable steady state operation. Voltage holding and radiation effects on the acceleration grid structure are discussed. We also briefly describe the vacuum system and analyze use of a direct energy converter to recapture energy from unneutralized ions exiting the neutralizer. Of crucial importance to the technical feasibility of the3He-burning reactor are the injector efficiency and cost; these are 53% and $5.5 million, respectively, when power supplies are included.

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Author notes

  1. J. H. Fink

    Present address: Westinghouse Research and Development Center, Pittsburgh, Pa.

Authors and Affiliations

  1. Lawrence Livennore Laboratory, University of California, 94550, Livermore, Calif.

    A. S. Blum, W. L. Barr, W. L. Dexter, J. H. Fink, R. W. Moir & T. P. Wilcox

Authors
  1. A. S. Blum
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  2. W. L. Barr
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  3. W. L. Dexter
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  4. J. H. Fink
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  5. R. W. Moir
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  6. T. P. Wilcox
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Additional information

The beam is composed of 91 separate, parallel currents that flow in the gaps between the elements or wires of a grid. Each such flow is referred to as a “beamlet.” The current densities in Figs. 5, 8, and 9 are values within a beamlet, as measured at the beam-forming grid. They are not values averaged over the entire beam cross-section.

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Blum, A.S., Barr, W.L., Dexter, W.L. et al. Design study of a 120-keV,3He neutral beam injector. J Fusion Energ 1, 69–86 (1981). https://doi.org/10.1007/BF01050450

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  • DOI: https://doi.org/10.1007/BF01050450

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