A promising scheme for the chemical processing of a thorium breeder reactor of the two-region aqueous homogeneous type consists of the following operations: concentration of insoluble fission and corrosion products from the core system into a small volume of fuel solution, combining this slurry with irradiated thorium oxide slurry taken from the blanket, recovery of D2O by evaporation, dissolution of the thorium and uranium in HNO3, and, after a suitable cooling period, recovery of the uranium and thorium by solvent extraction for return to the reactor. The use of a hydroclone and underflow container arrangement for concentrating insoluble fission and corrosion products under simulated reactor conditions has been successfully demonstrated on dynamic loops. Solids concentration factors greater than 103 were demonstrated, and equilibrium solids concentration in the circulating solution less than 1 ppm was attained in these tests. Present data indicate that proper design and operation will minimize solids deposition in the reactor system and that the insoluble impurities can be effectively removed by the hydroclone. An alternate method of processing the slurry removed from the core system by the hydroclone consists of removing the room temperature insolubles by centrifugation, recovering the uranium from the supernatant by peroxide precipitation, thermal decomposition of the uranyl peroxide in dilute deuterated sulfuric acid to produce reactor fuel. This method has been successfully tested on a laboratory scale using a simulated hydroclone underflow slurry. Laboratory and loop studies of iodine chemistry indicate that iodine is sufficiently volatile under reactor conditions to be removed by gas stripping. The effect of radiation, temperature, and other fission products on iodine valence have been studied.