Preliminary survey of separations technology applicable to the pretreatment of Hanford tank waste (1992--1993)

Abstract

The U.S. Department of Energy has established the Tank Waste Remediation System (TWRS) to manage and dispose of radioactive wastes stored at the Hartford Site. Within this program are evaluations of pretreatment system alternatives through literature reviews. The information in this report was collected as part of this project at Pacific Northwest Laboratory. _'_ A preliminary survey of literature on separations recently entered into the Hanford electronic databases (1992-1993) that have the potential for pretreatment of Hanford tank waste was conducted. Separation processes that can assist in the removal of actinides (uranium, plutonium, americium), lanthanides, barium, 137Cs,9°Sr, 129I,63Ni, and 99Tcwere evaluated. Separation processes of interest were identified through literature searches, journal reviews, and participation in separation technology conferences. This report contains brief descriptions of the potential separation processes, the extent and/or selectivity of the separation, the experimental conditions, and observations. Information was collected on both national and international separation studies to provide a global perspective on recent research efforts. Separation processes are listed in groups of unit operations under each constituent(s) to be separated. The separations processes described in this text are listed below in Table S. 1 with the author(s) and publication year. All these processes are deemed to have potential applicability to the treatment of tank waste. The processes that are recomme_.ded for further study are listed in Table S.2 with some of their positive attributes. These separations processes were selected on the basis that they have recently received attention for application in radioactive environments. The processes of interest include extraction, emulsion-liquid membranes, ion exchange, and ion flotation. These processes offer the potential for good separations, are relatively simple, and do not generate large amounts of secondary waste. The performance of these processes with actual tank waste can only be speculated since a limited amount of information is currently available. Information compiled in this study has enabled PNL to identify a broad spectrum of recent research efforts that may have potential applications for the pretreatment of Hanford tank waste. However, it was anticipated that many applicable articles would be omitted on a topic as broad as separations. Thus, it was the intent of this report to provide a representative cross-section of recent separations studies. The scope of this study does not provide an exhaustive survey but provides recent information on a broad scale. In part, it is the intent of this review to provide articles from which a more detailed search specific to each technology or constituent can be based. This study builds upon three detailed constituent reviews on cesium, strontium, and transuranic wastes completed during FY93. (a) Pacific Northwest Laboratory is operated for the U.S. Department of Energy by Battelle Memorial Institute...