Design of Closed-Cycle Helium Turbine Nuclear Power Plants

This paper describes the design of two closed-cycle helium turbine electric power plants using a modular high temperature gas-cooled reactor (MGR) as heat source. The MGR-GT utilizes a direct cycle with the turbine in the primary coolant loop while the MGR-GTI uses an intermediate heat exchanger. Both plants are based on current technologies and offer busbar efficiencies in excess of 45% at generating costs competitive with other nuclear or fossil systems. The MGR-GTI indirect cycle faces less technical challenge and is easier to license under current technical and institutional realities, whereas the MGR-GT direct cycle is better able to accommodate future developments in fuel and materials and is an ultimate design capable of capturing the full economic potential through further design simplicity. The two designs thus provide an evolutionary path for the commercialization of MGR gas turbine technology.