This report describes a horizontal, compact agitated-film concentrator called a Rototherm, manufactured by Artisan Industries, Inc. which can be used to process aqueous solutions of radioactive wastes containing plutonium. The unit is designed to concentrate liquid streams to a high-solid content slurry

Chamberlain, D.B.

Chen, L.

Conner, C.

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- PREPRINTED EXTEiUDED ABSTRACT Presented at the I&EC Special Symposium American Chemical Society Atlanta, GA, September 17-20,1995 A Portable Concentrator for Processing Plutonium Containing Solutions* D. B. Chamberlain, C. Conner, L. Chen, D. G. Wygmans, and G. F. Vandegrift Chemical Technology Division Argonne National Laboratory 9700 South Cass Avenue Argonne, Illinois 60439 The submitted manuscript has been authored by a contractor of the U. S. Government under contract No. W-31-109-ENG-3. Accordingly, the U. S. Government retains a nonexclusive, royalty-free license t o  publish or reproduce the published form of this contribution, or allow others to do so, for U. S. Government purposes. Many DOE facilities that have handled large quantities of aqueous plutonium solutions are being deactivated. Draining and flushing of the equipment used to process these solutions (piping, tankage, gloveboxes, ventilation ducts, etc.) are expected to generate substantial quantities of liquids containing accountable quantities of plutonium. A portable, modular unit is needed that can process a variety of these solutions with minimal systems reactivation. This unit would be capable of handling acidic and basic solutions and slurries with plutonium concentrations ranging up to 100 grams per liter. The system must also be criticality safe and be capable of producing high decontamination factors (i.e. low contamination levels in the distillate). Artisan Industries, Inc. (Waltham, MA) manufactures a compact, horizontal agitated-film concentrator called a Rototherm (see Fig. 1). This unit is designed t o  concentrate liquid streams to a high-solid-content slurry. Steam is typically used to heat the concentrator body, where an internal bladed rotor creates a thin turbulent film on the evaporator surface, causing the liquid to vaporize. The vapor then flows into the vaporfliquid separation region, where entrained liquid is removed from the vapor stream by mesh pads. The Rototherm's horizontal design with internal rotor allows i t  to evaporate solutions to high-solid content. Rototherms have been used to concentrate streams containing foaming detergents, alkaline permanganate, ammonium citrate, boric acid, sodium nitrates, carbonates, sulfates, hydroxides, and aluminates. Feeds have ranged from 0.01% total solids (dissolved plus suspended) to greater than 35% total solid. Capabilities for evaporating 98+% of the water present in a single pass have been demonstrated. Thus, considerable volume reduction is possible. In general, Rototherms can be operated continuously without shut downs for cleaning and maintenance, making them very attractive for radioactive service, where maintenance and * Work Supported by the U.S. Department of Energy, Environmental Remediation and Waste Management, under Contract W-31-109-Eng-38. w DISTRIBUTION OF THIS DOCUMENT IS UNLIMITED DISCLAIMER Portions of this document may be illegible in electronic image products. Images are produced from the best available original document. Vapor Turbulent, Steam t Bo'ttoms Discharge t Condensate Fig. 1. Artisan Rototherm Concentrator. The Rototherm is designed for minimal solution holdup. This makes it ideal for processing solutions where criticality is a concern. The entire unit c in  easily be. made criticality safe by geometry by keeping all pipe diameters less than 15 cm (6 in.). A criticality-safe unit has been built for the Rocky Flats Plant. The glovebox or lightly shielded concentrator system is being designed to be portable (modular), efficient, criticality safe by geometry, and self contained (only electrical power required) to generate a distillate product that is essentially free of activity. An initial design of such a system is shown in Fig. 2. Because of the criticality safety requirement, the diameter of the Rototherm body is expected to be less than 15 cm (6 inches). Typical throughput for units of this size (5 ft2 heat transfer surface area) is about 170 U r .  Decontamination factors in the range of 10 6 7  -10 are expected with this system. Another area of interest to potential users is the processing of decontamination solutions that will be generated throughout the DOE complex. One such area is in the decontamination of the gaseous diffusion plants. The use of gaseous reagents to  clean these systems is expected to be very slow; treatment times on the order of 6 months may be common. Use of aqueous decontamination solutions would greatly speed up the cleanup process, bu t  aqueous waste treatment systems are not available in these facilities. Use of a portable concentrator to  recycle reagents and minimize waste generation may be very applicable. Results from simulant tests to determine the applicability of this unit for these types of service are discussed. In addition, the conceptual design for a portable concentrator system is described. Inlet Outlet t VaporLiquid Separator \ Feed "1 HEPA1 Concentrator Rotor -Electric Heater - * - l i  Distillate Storage plingMedia/- 1 Distillate Storage \ \  Glovebox Boundaq U Solid Scintillator for Alpha Detection Recirckating Cooling unit Fig. 2. Initial Concept, Mobile Concentrator System DISCLAIMER This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsi- bility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Refer- ence herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recom- mendation, or favoring by the United States Government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof. 

A portable concentrator for processing plutonium containing solutions

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