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Review of direct energy conversion for fusion reactors (open access)

Review of direct energy conversion for fusion reactors

The direct conversion to electrical energy of the energy carried by the leakage plasma from a fusion reactor and by the ions that are not converted to neutrals in a neutral-beam injector is discussed. The conversion process is electrostatic deceleration and direct particle collection as distinct from plasma expansion against a time-varying magnetic field or conversion in an EXB duct (both MHD). Relatively simple 1-stage plasma direct converters are discussed which can have efficiencies of about 50 percent. More complex and costly (measured in $/kW) 2-, 3-, 4-, and 22-stage concepts have been tested at efficiencies approaching 90 percent. Beam direct converters have been tested at 15 keV and 2 kW of power at 70 +- 2 percent efficiency, and a test of a 120-keV, 1-MW version is being prepared. Designs for a 120-keV, 4-MW unit are presented. The beam direct converter, besides saving on power supplies and on beam dumps, should raise the efficiency of creating a neutral beam from 40 percent without direct conversion to 70 percent with direct conversion for a 120-keV deuterium beam. The technological limits determining power handling and lifetime such as space-charge effects, heat removal, electrode material, sputtering, blistering, voltage holding, and insulation design, …
Date: September 20, 1976
Creator: Barr, W. L. & Moir, R. W.
System: The UNT Digital Library