[en] A most challenging and interesting application of the closed-cycle gas turbine for electrical power generation is a plant with a high temperature gas cooled reactor (HTGR) as the heat source, and this paper presents the design studies for a 1200 MW(e) plant. The GT-HTGR plant combines the existing HTGR core with a closed-cycle helium gas turbine power conversion system which operates on the same helium used as the reactor coolant. In this series of lectures a summary is given of the design evolution for a large nuclear closed-cycle gas turbine power plant study by the General Atomic Company for U.S. utility central stations. The presentation includes a background on closed-cycle gas turbines, the incentives for the GT-HTGR, cycle selection, plant configuration studies, performance, selection of a reference plant design, component design activities, and a description of the waste heat binary power plant. Included also are development and testing alternatives, and related international programs in the closed-cycle gas turbine field