A radiological assessment was performed for a reprocessing plant handling advanced liquid-metal fast breeder reactor (LMFBR) fuels, and the results were compared with those for reference oxide fuel. Candidate advanced fuels analyzed included l(U,Pu)Cl and f(U,Pu)Nj with selected concentrations of i5N. Core neutronics and designs appropriate to advanced-fueled LMFBRs were used with the ORIGEN computer code to calculate compositions of spent core and blanket fuel equivalent to 50 GW-yr of electrical energy generation. Confinement factors, specific to each radionuclide released to the atmosphere at the reprocessing plant, were used to calculate source terms describing the emission of radionuclides. Radiological impact within a 80-km radius of the facility was determined with the AIRDOS-II computer code, while the dose to the world population from 14C released at the reprocessing plant was estimated with a multicompartment global carbon cycling model. For carbide fuel, the calculated dose commitment to the total body of the maximally exposed individual was ∼2.8 mrem. Corresponding dose commitments when nitride fuels were substituted ranged between 59 and 3.4 mrem, as the 14N content in fuel was varied from 99.64%, the natural abundance of 14N, to zero (i.e., 100% enrichment with 15N), respectively. Dose commitment to the world population from l4C produced in nitride fuel made with natural nitrogen may prohibit use of this fuel from an environmental standpoint. However, a combination of ,SN enrichment in the fuel and confinement of at least part of the 14C at the reprocessing plant can significantly reduce both the amount of 14C ultimately released to the atmosphere and the global impact from 14C. It was concluded that no major differences exist in the radiological impact when carbide fuel is substituted for oxide fuel at the reprocessing plant. The use of nitride fuel may, however, require substantial enrichment with 15N or significant improvement in effluent treatment techniques proposed for 14 C retention.