[en] ERDA commissioned Arthur D. Little, Inc. (ADL) to make a brief but intensive study of the current status of, and the courses of action open to, the government in connection with the development and commercialization of the following four reactor types: High Temperature Gas-Cooled Reactor-Steam Cycle (HTGR-SC), Direct Conversion High Temperature Reactor (DCHTR), Very High Temperature Reactor (VHTR), Gas-Cooled Fast Breeder Reactor (GCFR). The study was structured to address the following specific tasks: carry out a technical and economic assessment of the status of technology of the reactor types; develop a spectrum of scenarios projecting the performance of these reactor types, their areas of potential application and schedule of commercial availability; develop alternative scenarios for providing required electrical energy and process heat within the United States against which the value of possible gas-cooled reactor development can be measured; and provide development and commercial deployment strategies for gas-cooled reactors