Neutronics characteristics of space power reactors

This report presents a brief description of the neutronics characteristics of selected conceptual designs for space reactors. Parametric studies also are included to delineate the effects of possible design changes. Although a wide range of power densities and sizes is considered, the focus is on reactors that provide roughly 1 Mwt to 50 Mwt. Both ceramic (UO2 and UN in clad pins) fueled reactors and cermet (Mo, W, and Ta matrix) fueled reactors are examined. Although ceramic fuels have become the standard for power reactors, cermet fuels exhibit several desirable attributes for space applications. These attributes include greater structural strength and a more reliable reactivity expansion coefficient