[en] Design studies have been carried out to examine alternatives and to critically evaluate selected key technological problems in the initial conceptual design of a doublet tokamak demonstration plant. Reactor characteristics and the general arrangement are examined, and emphasis is given to those reactor systems that are most influenced by the doublet configuration. In particular, this study has concentrated on a reactor technical and economic systems analysis over a wide range of power output and important reactor parameters, the integrated performance and design of the blanket-field-shaping coil/plasma subsystems, and an overall reactor maintenance scenario. The reactor has a 5.34 m major radius and a net electrical output of 307 MW(e). The blanket incorporates Li₇Pb₂ for breeding, a high nickel base alloy structure, and is helium cooled. The magnet systems consist of superconducting toroidal and ohmic heating coils, and normal copper field-shaping coils. The nine toroidal coils have a maximum field of 8.8 T. The plasma is heated by up to 80 MW of lower hybrid rf power. The reactor arrangement is strongly influenced by remote maintenance requirements and a two stage vacuum zone approach