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Abstract
A caustic‐side solvent extraction (CSSX) process was developed to remove Cs from Savannah River Site (SRS) high‐level waste. The CSSX process was verified in a series of flowsheet tests at Argonne National Laboratory (ANL) in a minicontactor (2‐cm centrifugal contactor) using simulant. The CSSX solvent, which was developed at Oak Ridge National Laboratory (ORNL), consists of a calixarene‐crown ether as the extractant, an alkyl aryl polyether as the modifier, trioctylamine as the suppressant, and Isopar®L as the diluent. For Cs removal from the SRS tank waste, the key process goals are that: (1) Cs is removed from the waste with a decontamination factor greater than 40,000 and (2) the recovered Cs is concentrated by a factor of 15 in dilute nitric acid. In the flowsheet verification tests, the objectives were to: (1) prove that these process goals could be met; (2) demonstrate that they could be maintained over a period of several days as the CSSX solvent is recycled; and (3) verify that the process goals could still be met after the solvent composition was adjusted. The change in composition eliminated the possibility that the calixarene‐crown ether could precipitate from the solvent. The process goals were met for each of the verification tests. The results of these tests, which are summarized here, show that the CSSX process is a very effective way to remove Cs from caustic‐side waste.
#The submitted manuscript has been created by the University of Chicago as Operator of Argonne National Laboratory (“Argonne”) under Contract No. W‐31‐109‐ENG‐38 with the U.S. Department of Energy. The U.S. Government retains for itself, and others acting on its behalf, a paid‐up, nonexclusive, irrevocable worldwide license in said article to reproduce, prepare derivative works, distribute copies to the public, and perform publicly and display publicly, by or on behalf of the Government.
Acknowledgments
This work was supported by the Office of Environment Management of the U.S. Department of Energy through (1) the Office of Project Completion and (2) the Tank Focus Area of the Office of Science and Technology under Contract W‐31‐109‐Eng‐38 with Argonne National Laboratory, managed by the University of Chicago.
The authors wish to acknowledge the help of Manuel Almazan, Allen Bakel, John Basco, Del Bowers, Jim Byrnes, Jeff Emery, Bob Finch, Evan Freiberg, Joe Hirsch, Kevin Quigley, Artem Guelis, Joe Hirsch, Frank Markun, Kevin Quigley, Lillian Ruscic, and Mark Sreniawski, all of the ANL Chemical Technology Division, and Greg Dolnak, ANL Waste Management Operations, in preparing for and carrying out the CSSX flowsheet tests. Peter Bonnesen of ORNL prepared the CSSX solvent used in these tests. Tests CS23, CS24, and CS25 were observed by Reid Peterson and Paul Rutland, both of Westinghouse Savannah River Company (WSRC). Tests CS23 and CS24 were observed by Ken Rueter of WSRC. Tests CS23 and CS25 were observed by Joe Carter of WSRC. Test CS27 was observed by Leon Klatt of ORNL and Seth Campbell of WSRC. Analyses for solvent degradation products after test CS27 were carried out at ORNL under the direction of Bruce Moyer.
Notes
#The submitted manuscript has been created by the University of Chicago as Operator of Argonne National Laboratory (“Argonne”) under Contract No. W‐31‐109‐ENG‐38 with the U.S. Department of Energy. The U.S. Government retains for itself, and others acting on its behalf, a paid‐up, nonexclusive, irrevocable worldwide license in said article to reproduce, prepare derivative works, distribute copies to the public, and perform publicly and display publicly, by or on behalf of the Government.