Under the sponsorship of the Electric Power Research Institute, a design concept has been developed for an integrated nuclear fuels reprocessing/recycle fuels fabrication plant which (a) could be authorized for detailed design in 1986, (b) would be capable of reprocessing 1500 tonnes of irradiated light water reactor (LWR) fuel [or lesser quantities of fast breeder reactor (FBR) fuel] per year and incorporating the recovered plutonium in FBR fuel, (c) could be operated safely, reliably, and economically, and (d) would illustrate a level of diversion resistance practicably attainable in a commercially sized and licensable facility. The design concept resulting from this study has been named SAFAR (an acronym for Safeguarded Fabrication and Reprocessing). The SAFAR concept includes a modified Purex process flow sheet coupled via a sol-gel conversion with a sphere-pac/sphere-cal process for fuel fabrication. The basic Purex flow sheet is modified so that plutonium moves through the system in essentially plug flow. This permits a rapid depletion of the plutonium inventory in the solvent extraction system, thereby making it possible to take a plant inventory in 24 h. In the sphere-pac process, the fuel is loaded into evacuated fuel rods as sintered oxide spheres. By concurrently loading three sizes of spheres with tube vibration, desired fuel densities (∼88%) can be obtained. This process permits the plutonium to be stored, transported, and added to the rods remotely. As an alternative, the sphere-cal process may be preferred for fuel fabrication. In the sphere-cal process, calcined oxide spheres are pressed into pellets and sintered. While this process is probably less desirable than sphere-pac from a safeguards viewpoint (more operator contact with plutonium would probably be required), the sphere-cal fuel might be viewed as more nearly comparable to conventional fuel with its well-established technical bases. The following features are specifically included in the SAFAR design concept to meet U.S. Nuclear Regulatory Commission and/or International Atomic Energy Agency safeguards goals:1. Remote operation and equipment replacement techniques are used to limit personnel access to unencapsulated plutonium.2. In a plant designed to process 1500 tonnes of irradiated LWR fuel per year (∼13 000 kg of plutonium per year), the in-process inventory could be measured with an uncertainty < 6 kg Pu every 15 days with a minimal production loss. The long-term uncertainty in plutonium mass balances would be ∼0.35%.3. Material control and accountancy (MC&A) is accomplished through the use of a separate MC&A office. Pertinent measurements are made available electronically to the MC&A office concurrently (in parallel) with their availability to production personnel.4. The plant safeguards design is based on eight internal material balance areas and two item control areas.5. The plant layout is such that only specifically authorized personnel could enter that segment of the plant that contains plutonium.6. Under emergency conditions, personnel could retreat to a subgrade room where they would be protected from radiation, noxious chemicals, and/or terrorists. Exit would be via a guard station.