The neutronics of several fusion-fission hybrid reactors were studied to develop a design capable of producing 233U while maintaining a self-sufficiency in tritium. High breeding rates are achieved by using an equilibrium concentration of 238U and 239Pu instead of thorium in a converter region to produce a significantly greater multiplication of the 14-MeV source neutrons. The final blanket design has an 18-cm neutron converter that consists of 0.5-in-diam pins of 92% 238U/8% 239Pu with a 0.7-in. pitch. The 40-cm breeding region consists of 0.5-in.-diam pins of ThC with 0.6-in. pitch; the overall blanket thickness is 102 cm. The tritium and fissile breeding ratios are 1.052 and 1.880, respectively, and there are 3.537 233U nuclei produced per fusion neutron. An analysis of the performance of the blanket over a 2-yr period was carried out, including the buildup and depletion of fissionable nuclides and fission products. The final design requires an inventory of ∼30 000 kg of 239Pu, which must be produced for the design to be viable. A preliminary static and time-dependent study was done for a startup cycle to serve this purpose.