The key to managing the disposal of used nuclear fuel is not to consider it as a waste but rather as a resource. In a closed nuclear fuel cycle, the removal and transmutation of high specific activity isotopes can be accomplished to reduce the radiation levels of high level wastes to near uranium mineral levels after a few hundred years. Dissolved used nuclear fuel mixtures include U, Np, Pu, trivalent transplutonium actinides and lanthanides and other fission products, representing a total of about 1/3 of the periodic table. Americium, being a long-lived α-emitter, is the greatest contributor to the radiotoxicity of the waste in the 300-70,000 year time frame after removal from the reactor. The lanthanides, representing about 40% of the mass of fission products, are neutron poisons. They interfere with the transmutation process, necessitating removal before transmutation of the waste can be performed. The mutual separation of Am from chemically similar lanthanides remains one of the largest obstacles to the implementation of a closed nuclear fuel cycle in which Am is transmuted.

Two possible pathways exist that could be utilized in the separation Am from Cm and the lanthanides. These pathways make use of selective oxidation of the actinide or soft donor complexants to perform a given separation. This dissertation contains a description of kinetics of lanthanide complexation and redox adjustment of americium followed by precipitation of the lanthanide to achieve actinide separations. The separations will be based on oxidation states and soft donor effects. Separations that will be performed in an advanced fuel cycle will take advantage of both of these aspects to make a successful reprocessing scheme.