Centrifugal Contactor Operations for UREX Process Flowsheet.

摘要

The UREX process separates uranium, technetium, and a fraction of the iodine from the other components of the irradiated fuel in nitric acid solution. The time and equipment requirements were evaluated for treatment of 260-L batches of a solution containing 130 g-U/L using commercial annular centrifugal contactors from CINC Industries. An earlier evaluation was done assuming 150 L of feed solution per batch. Two different contactor versions from CINC were evaluated, the V-2 and V-5 units. The V-2 has a 2-in. (5-cm) rotor with a reported maximum total organic-plus-aqueous throughput of 1.9 L/min. We evaluated this version for a throughput of 1 L/min. The V-5 has a 5-in. (~12.5-cm) rotor with a reported maximum throughput of 19 L/min. We evaluated this unit for throughputs of 10 and 15 L/min. The lower-than-maximum throughputs selected for this evaluation are based on the Argonne National Laboratory (Argonne) ROTOR model, which calculates the operational envelope for a given process O:A (organic-flow-rate/aqueous-flow-rate) ratio based on contactor parameters (weir dimensions, rotor diameter, etc.), the physical properties of the two immiscible fluids, and the allowable other-phase-carryover. Because the UREX process designed for this application has O:A ratios ranging from 0.8 to 5.6, adjustments to the weirs in different sections of the contactor bank can broaden the operational envelope for satisfactory separations, but throughput will remain short of the equipment maximum due to the physical characteristics of the two phases.