In order to construct a D-T fusion-fission hybrid breeder reactor there must be some guarantee that tritium will be available to fuel the fusion reaction. This can be achieved by breeding tritium in the blanket of the reactor. A variety of blanket configurations have been studied with the intent of arriving at a blanket design capable of attaining sizeable values of power and fissile fuel production, and simultaneously assure self-sufficiency in tritium production for the reactor, i.e., a T-breeding ratio greater than 1.0. Using a four group diffusion theory code, a number of possible blanket configurations were studied during the parametric phase of hybrid breeder blanket design. They included tritium breeding zones of natural or enriched lithium metal and natural lithium in dilithium oxide, neutron multiplier zones of uranium and thorium with varying amounts of plutonium, thorium fissile breeding zones (sometimes containing plutonium), and graphite reflector zones. The choice of clad used in the fuel rods has also been found to influence tritium breeding. One of the more promising designs studied combines a tritium breeding ratio of 1.2 with a blanket fissile power of 16 GW(th), and a U-233 production rate of 2.7 tonnes per year.

A preliminary evaluation of methods for the salt waste and waste water streams and recycle preparation problems was completed. A feasibility study for removing actinides from synthetic salt waste showed that a bidentate organophosphorus extractant is the most efficient for actinide removal. The evaluation of adsorbents for removing detergents and anions from waste water suggests the use of a combination of non-ionic and a strong base ion exchange resin for best results. Evaluation of leaching and dissolution methods for the recovery of actinides from combustible waste (incinerator ash) was continued. Two promising recovery methods are: (1) reaction with cerium(IV) in nitric acid to solubilize carbon and actinide oxides, and (2) fusion with carbonate--nitrate mixtures. Silica proved to be a problem. If dissolved, it interferes with subsequent actinide recovery by forming polysilicic acid upon acidification. If not solubilized, silica-encapsulated actinide oxides may not be contacted by the dissolvent. Pretreatment of ash by refluxing with greater than or equal to 6M sodium hydroxide appears to remove silica, simplifying subsequent recovery steps.