Author: Richard A. Bartsch Publisher: ISBN: Category : Languages : en Pages : 5
Book Description
General project objectives. This project seeks a fundamental understanding and major improvement in cesium separation from high-level waste by cesium-selective calixcrown extractants. Systems of particular interest involve novel solvent-extraction systems containing specific members of the calix[4]arene-crown-6 family, alcohol solvating agents, and alkylamines. Questions being addressed pertain to cesium binding strength, extraction selectivity, cesium stripping, and extractant solubility. Enhanced properties in this regard will specifically benefit cleanup projects funded by the USDOE Office of Environmental Management to treat and dispose of high-level radioactive wastes currently stored in underground tanks at the Savannah River Site (SRS), the Hanford site, and the Idaho National Environmental and Engineering Laboratory. 1 The most direct beneficiary will be the SRS Salt Processing Project, which has recently identified the Caustic-Side Solvent Extraction (CSSX) process employing a calixcrown as its preferred technology for cesium removal from SRS high level tank waste. 2 This technology owes its development in part to fundamental results obtained in this program.
Author: Bruce A. Moyer Publisher: ISBN: Category : Languages : en Pages : 5
Book Description
Calix[4]arenebiscrown-6 molecules are currently the selected technology for removal of radioactive cesium-137 from DOE nuclear wastes. By attachment of an acidic function to such molecules, the efficiency with which cesium ion can be extracted from an aqueous solution into an organic diluent is markedly increased since the requirement for concomitant extraction of an aqueous phase anion is avoided. Thus, cesium ion extraction by proton-ionizable calix[4]arenebiscrown-6 molecules may be the ''second-generation'' technology for removal of cesium-137 from DOE nuclear wastes. During Year 1 of this EMSP project, we have established synthetic routes to new, lipophilic, proton-ionizable calix[4]arenebiscrown-6 molecules to be evaluated for solvent extraction of cesium ion at Oak Ridge National Laboratory. Analogous calix[4]arenecrown-6 compounds are also being prepared to determine if even higher cesium ion selectivities can be obtained with extractants having a single crown ether unit.
Author: Publisher: ISBN: Category : Languages : en Pages : 5
Book Description
This project seeks a fundamental understanding and major improvement in cesium separation from high-level waste by cesium-selective calixcrown extractants. Systems of particular interest involve novel solvent-extraction systems containing specific members of the calix[4]arene-crown-6 family, alcohol solvating agents, and alkylamines. Questions being addressed pertain to cesium binding strength, extraction selectivity, cesium stripping, and extractant solubility. Enhanced properties in this regard will specifically benefit cleanup projects funded by the USDOE Office of Environmental Management to treat and dispose of high-level radioactive wastes currently stored in underground tanks at the Savannah River Site (SRS), the Hanford site, and the Idaho National Environmental and Engineering Laboratory. 1 The most direct beneficiary will be the SRS Salt Processing Project, which has recently identified the Caustic-Side Solvent Extraction (CSSX) process employing a calixcrown as its preferred technology for cesium removal from SRS high-level tank waste. 2 This technology owes its development in part to fundamental results obtained in this program.
Author: Richard A. Bartsch Publisher: ISBN: Category : Languages : en Pages :
Book Description
Solvent extraction with a lipophilic calix[4]arenebiscrown-6 ligand is currently the selected technology for removal of radioactive cesium-137 from DOE nuclear wastes. In this collaborative DOE-EMSP project, related "second-generation" extractants are being synthesized at Texas Tech University (TTU) and their alkali metal cation compexation and separation abilities evaluated at TTU and Oak Ridge National Laboratory (ORNL). The novel feature of the "second-generation" calix[4]arenecrown extractants is incorporation of a proton-ionizable group into the ligand structure. This modification markedly enhances the efficiency with which metal ions can be extracted from an aqueous phase into an organic diluent, since concomitant extraction of a hydrophilic anion from the aqueous solution into the hydrophobic organic phase is avoided. During Year 1 of this EMSP project, we established synthetic routes to new, lipophilic, proton-ionizable calix[4]arenebiscrown-6 molecules at TTU and prepared them in sufficient quantities that their efficiency and selectivity in alkali metal cation extraction could be evaluated at ORNL using radiotracer techniques. In Year 2, we have prepared a series of related lipophilic, proton-ionizable calix[4]arenecrown-6 molecules to determine if even higher cesium ion selectivities can be obtained when the extractant has only a single crown ether unit. Evaluation of the these ligands at ORNL has revealed their greater solubility in low polarity organic diluents than that of analogous lipophilic, proton-ionizable calix[4]arenebiscrown-6 ligands. In Year 3, we will continue the synthesis of lipophilic, proton-ionizable calix[4]arenecrown-6-type compounds for evaluation of the influence of varying the acidity of the proton-ionizable group, as well as its positioning with respect to the crown ether ring in which the metal ion is complexed. Special emphasis will be placed on developing practical preparative routes to promising extractants.
Author: Bruce A. Moyer Publisher: CRC Press ISBN: 142005970X Category : Science Languages : en Pages : 682
Book Description
The growth in the world's nuclear industry, motivated by peaking world oil supplies, concerns about the greenhouse effect, and domestic needs for energy independence, has resulted in a heightened focus on the need for next-generation nuclear fuel-cycle technologies. Ion Exchange and Solvent Extraction: A Series of Advances, Volume 19 provides a com
Author: JR. J. F. Birdwell Publisher: ISBN: Category : Languages : en Pages :
Book Description
This report presents the results of a conceptual design of a solvent extraction process for the selective removal of {sup 137}Cs from high-level radioactive waste currently stored in underground tanks at the U.S. Department of Energy's Savannah River Site (SRS). This study establishes the need for and feasibility of deploying a simplified version of the Caustic-Side Solvent Extraction (CSSX) process; cost/benefit ratios ranging from 33 to 55 strongly support the considered deployment. Based on projected compositions, 18 million gallons of dissolved salt cake waste has been identified as having {sup 137}Cs concentrations that are substantially lower than the worst-case design basis for the CSSX system that is to be deployed as part of the Salt Waste Processing Facility (SWPF) but that does not meet the waste acceptance criteria for immobilization as grout in the Saltstone Manufacturing and Disposal Facility at SRS. Absent deployment of an alternative cesium removal process, this material will require treatment in the SWPF CSSX system, even though the cesium decontamination factor required is far less than that provided by that system. A conceptual design of a CSSX processing system designed for rapid deployment and having reduced cesium decontamination factor capability has been performed. The proposed accelerated-deployment CSSX system (CSSX-A) has been designed to have a processing rate of 3 million gallons per year, assuming 90% availability. At a more conservative availability of 75% (reflecting the novelty of the process), the annual processing capacity is 2.5 million gallons. The primary component of the process is a 20-stage cascade of centrifugal solvent extraction contactors. The decontamination and concentration factors are 40 and 15, respectively. The solvent, scrub, strip, and wash solutions are to have the same compositions as those planned for the SWPF CSSX system. As in the SWPF CSSX system, the solvent and scrub flow rates are equal. The system is designed to facilitate remote operation and direct maintenance. Two general deployment concepts were considered: (1) deployment in an existing but unused SRS facility and (2) deployment in transportable containers. Deployment in three transportable containers was selected as the preferred option, based on concerns regarding facility availability (due to competition from other processing alternatives) and decontamination and renovation costs. A risk assessment identified environmental, safety, and health issues that exist. These concerns have been addressed in the conceptual design by inclusion of mitigating system features. Due to the highly developed state of CSSX technology, only a few technical issues remain unresolved; however, none of these issues have the potential to make the technology unviable. Recommended development tasks that need to be performed to address technical uncertainties are discussed in this report. Deployment of the proposed CSSX-A system provides significant qualitative and quantitative benefits. The qualitative benefits include (1) verification of full-scale contactor performance under CSSX conditions that will support SWPF CSSX design and deployment; (2) development of design, fabrication, and installation experience bases that will be at least partially applicable to the SWPF CSSX system; and (3) availability of the CSSX-A system as a means of providing contactor-based solvent extraction system operating experience to SWPF CSSX operating personnel. Estimates of fixed capital investment, development costs, and annual operating cost for SRS deployment of the CSSX-A system (in mid-2003 dollars) are $9,165,199, $2,734,801, and $2,108,820, respectively. When the economics of the CSSX-A system are compared with those of the baseline SWPF CSSX system, benefit-to-cost ratios ranging from 20 to 47 are obtained. The benefits in the cost/benefit comparison arise from expedited tank closure and reduced engineering, construction, and operating costs for the SWPF CSSX system. No significant impediments to deployment were determined in the reported analysis, and where technical uncertainties were identified, development tasks to mitigate them are indicated. It is recommended that deployment of the CSSX-A system be pursued in a timely manner in order to derive the greatest possible cost and accelerated treatment benefits.
Author: Publisher: ISBN: Category : Languages : en Pages : 5
Book Description
Researchers at the Savannah River Technology Center (SRTC) successfully demonstrated the Caustic-Side Solvent Extraction (CSSX) process flow sheet using a 33-stage, 2-cm centrifugal contactor apparatus in two 24-hour tests using actual high level waste. Previously, we demonstrated the solvent extraction process with actual SRS HLW supernatant solution using a non-optimized solvent formulation. Following that test, the solvent system was optimized to enhance extractant solubility in the diluent by increasing the modifier concentration. We now report results of two tests with the new and optimized solvent.
Author: National Research Council Publisher: National Academies Press ISBN: 0309052262 Category : Science Languages : en Pages : 590
Book Description
Disposal of radioactive waste from nuclear weapons production and power generation has caused public outcry and political consternation. Nuclear Wastes presents a critical review of some waste management and disposal alternatives to the current national policy of direct disposal of light water reactor spent fuel. The book offers clearcut conclusions for what the nation should do today and what solutions should be explored for tomorrow. The committee examines the currently used "once-through" fuel cycle versus different alternatives of separations and transmutation technology systems, by which hazardous radionuclides are converted to nuclides that are either stable or radioactive with short half-lives. The volume provides detailed findings and conclusions about the status and feasibility of plutonium extraction and more advanced separations technologies, as well as three principal transmutation concepts for commercial reactor spent fuel. The book discusses nuclear proliferation; the U.S. nuclear regulatory structure; issues of health, safety and transportation; the proposed sale of electrical energy as a means of paying for the transmutation system; and other key issues.
Author: Richard A. Bartsch
Author: Bruce A. Moyer
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Author: Richard A. Bartsch
Author: Bruce A. Moyer
Author: JR. J. F. Birdwell
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Author: National Research Council
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