This technical report describes the development, design, operation, and performance of a full-circle, radial-vane steam separator for the boiling water section of a nuclear superheat reactor. Steam-water tests of this model have demonstrated that is has vane capacity in excess of that required for the 300-Mx(e) separate superheat reactor and for the 300-Mw mixed spectrum superheat reactor. It is proposed that the vane capacity requirement of the 600 Mw(e) separate superheat reactor may be attained by increasing the nozzle length.