ADVANCED REMOTE MAINTENANCE DESIGN FOR PILOT-SCALE CENTRIFUGAL CONTACTORS

Advanced designs of spent nuclear fuel recycling processes and radioactive waste treatment processes are expected to include more ambitious goals for aqueous-based separations, including higher separation efficiency, high-level waste minimization, and a greater focus on continuous processes to minimize cost and footprint. Therefore, annular centrifugal contactors are destined to play a more important role for such future processing schemes. Pilot-scale testing will be an integral part of development of many of these processes. An advanced design for remote maintenance of pilot-scale centrifugal contactors has been developed and a prototype module fabricated and tested for a commercially available pilot-scale centrifugal contactor (CINC V-02, 5-cm rotor diameter). Advanced design features include air-actuated clamps for holding the motor/rotor assembly in place, an integral electrical connection, upper flange O-rings, a welded bottom plate, a lifting bale, and guide pins. These design features will allow for rapid replacement of the motor/rotor assembly, which can be accomplished while maintaining process equilibrium in the operating contactors during replacement of a unit. This means that fluids in the operating contactors remain at equilibrium with respect to composition and that process solutions are ready to resume discharge when the contactor is replaced and feed solutions are restarted. Hydraulic testing of a three-stage prototype unit was also performed to verify that design changes did not impact performance of the centrifugal contactors. Details of the pilot-scale remote maintenance design, results of testing in a remote mock-up test facility, and results of hydraulic testing of the advanced design are provided.