Configuration Development and Structural Assessment of the FEDC Ignitor Concept^*

* Research sponsored by the Office of Fusion Energy, U.S. Department of Energy, under Contract No. DE-AC05-840R21400 with Martin Marietta Energy Systems, Inc.

ABSTRACT

The Fusion Engineering Design Center (FEDC) performed a design study for a compact ignition tokamak based on the design approach established by Professor Bruno Coppi of the Massachusetts Institute of Technology in his Ignitor concept. His Ignitor concept has two unique features. First, the throat of the copper plate toroidal field (TF) coils is preloaded in the vertical direction to minimize the stress levels in the copper. Second, the net inward radial TF coil forces are balanced by a combination of wedging on the adjacent faces of the TF coils and by bucking against the ohmic heating solenoid coils in the bore of the tokamak. Later Ignitor concepts eliminated the wedging reactions. Both of these features inherently reduce the radial build of the tokamak device.

The FEDC version of Ignitor incorporates both of these unique features packaged in a different configurational arrangement. The FEDC Ignitor features a totally external preload system. The preload is applied directly to the inner leg of the TF coils in the vertical direction only. Horizontal rings are utilized only to react inplane TF coil forces and are not part of the preload system. Modular quadrants of TF coil encasements are utilized to vastly simplify device assembly methods. This design allows the entire core assembly to be constructed in a manufacturing facility and shipped to the site. The improved configuration also results in larger access ports direly needed for diagnostics and radio frequency heating units which may be required. This paper presents the configuration and a structural assessment of the FEDC Ignitor concept.

Notes

* Research sponsored by the Office of Fusion Energy, U.S. Department of Energy, under Contract No. DE-AC05-840R21400 with Martin Marietta Energy Systems, Inc.