Flexibility and Adaptability of Closed Brayton Cycles Associated With Low Power Level Space Nuclear Heat Sources

Abstract

A feature of the French preliminary studies of space nuclear power systems of about 20 kwe is the selection of the closed Brayton cycle as the conversion subsystem. As examples of future applications of turbogenerators in space, near or longer term U.S. and Soviet projects are mentioned, including technical advances expected in this field. Several nuclear reactors concepts can be proposed now or in the future. The need for a satisfactory adaptation between the heat source and the converter prompts to further investigate the Brayton cycle capability for that purpose. For instance, a long lifetime thermal spectrum reactor would require a relatively low inlet temperature for moderator thermal conditioning. Cycle configurations featuring one or two separate radiators and possible intercooling are presented. Such arrangements imply a main low temperature radiator made, for instance, of multiple, pivoting tubes. It is shown that the Brayton cycle can offer flexibility and adaptability for a wide range of space missions.