Download or read book Development and Properties of Crystalline Silicotitanate CST Ion Exchangers for Radioactive Waste Applications written by and published by . This book was released on 1997 with total page 61 pages. Available in PDF, EPUB and Kindle. Book excerpt: Crystalline silicotitanates (CSTs) are a new class of ion exchangers that were jointly invented by researchers at Sandia National Laboratories and Texas A & M University. One particular CST, known as TAM-5, is remarkable for its ability to separate parts-per-million concentrations of cesium from highly alkaline solutions (pH> 14) containing high sodium concentrations (>5M). It is also highly effective for removing cesium from neutral and acidic solutions, and for removing strontium from basic and neutral solutions. Cesium isotopes are fission products that account for a large portion of the radioactivity in waste streams generated during weapons material production. Tests performed at numerous locations with early lab-scale TAM-5 samples established the material as a leading candidate for treating radioactive waste volumes such as those found at the Hanford site in Washington. Thus Sandia developed a Cooperative Research and Development Agreement (CRADA) partnership with UOP, a world leader in developing, commercializing, and supplying adsorbents and associated process technology to commercialize and further develop the material. CSTs are now commercially available from UOP in a powder (UOP IONSIV{reg_sign} IE-910 ion exchanger) and granular form suitable for column ion exchange operations (UOP IONSIV{reg_sign} IE-911 ion exchanger). These materials exhibit a high capacity for cesium in a wide variety of solutions of interest to the Department of Energy, and they are chemically, thermally, and radiation stable. They have performed well in tests at numerous sites with actual radioactive waste solutions, and are being demonstrated in the 100,000 liter Cesium Removal Demonstration taking place at Oak Ridge National Laboratory with Melton Valley Storage Tank waste. It has been estimated that applying CSTs to the Hanford cleanup alone will result in a savings of more than $300 million over baseline technologies.

Download or read book Crystalline Silicotitanates new Ion Exchanger for Selective Removal of Cesium and Strontium from Radwastes written by and published by . This book was released on 1996 with total page 17 pages. Available in PDF, EPUB and Kindle. Book excerpt: A new class of inorganic ion exchange material called crystalline silicotitanates (CST) has been developed for radioactive waste treatment in a collaborative effort between Sandia National Laboratories and Texas A & M University. The Sandia National Laboratories Laboratory Directed Research and Development program provided the initial funding for this effort and this report summarizes the rapid progress that was achieved. A wide range of compositions were synthesized, evaluated for cesium (Cs) removal efficiency, and a composition called TAM-5 was developed that exhibits high selectivity and affinity for Cs and strontium (Sr). Tests show it can remove parts per million concentrations of Cs from highly alkaline, high-sodium, simulated radioactive waste solutions modeled after those at Hanford, Oak Ridge, and Savannah River. In experiments with solutions that simulate highly alkaline Hanford defense wastes, the crystalline silicotitanates exhibit distribution coefficients for Cs of greater than 2,000 ml/g, and distribution coefficients greater than 10,000 ml/g for solutions adjusted to a pH between 1 and 10. In addition, the CSTs were found to exhibit distribution coefficients for Sr+ greater than 100,000 ml/g and for plutonium of 2,000 ml/g from simulated Hanford waste. The CST crystal structure was determined and positions of individual atoms identified using x-ray and neutron diffraction. The structural information has permitted identification of the ion exchange sites and provided insights into the strong effect of pH on Cs ion exchange. Information on the synthesis, composition, and structure of CST is considered proprietary and is not discussed in this report.

Download or read book Preliminary Ion Exchange Modeling for Removal of Cesium from Hanford Waste Using Hydrous Crystalline Silicotitanate Material written by and published by . This book was released on 2004 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: For the current pretreatment facility design of the River Protection Project (RPP) Waste Treatment Plant (WTP), the removal of cesium from low activity waste (LAW) is achieved by ion-exchange technology based on SuperLig(R) 644 resin. Due to recent concerns over potential radiological and chemical degradation of SuperLig(R) 644 resin and increased pressure drops observed during pilot-scale column studies, an increased interest in developing a potential backup ion-exchanger material has resulted. Ideally, a backup ion-exchanger material would replace the SuperLig(R) 644 resin and have no other major impacts on the pretreatment facility flowsheet. Such an ideal exchanger has not been identified to date. However, Crystalline Silicotitanate (CST) ion-exchanger materials have been studied for the removal of cesium from a variety of DOE wastes over the last decade. CST ion-exchanger materials demonstrate a high affinity for cesium under high alkalinity conditions and have been under investigation for cesium removal specifically at Hanford and SRS during the last six years. Since CST is an inorganic based material (with excellent properties in regard to chemical, radiological, and thermal stability) that is considered to be practically non-elutable (while SuperLig(R) 644 is an organic based elutable resin), the overall pretreatment facility flowsheet would be impacted in various ways. However, the CST material is still being considered as a potential backup ion-exchanger material. The performance of a proposed backup ion-exchange column using IONSIV IE-911 (CST in its engineered-form) material for the removal of cesium from Hanford high level radioactive alkaline waste is discussed. This report focuses attention on the ion-exchange aspects and addresses the loading phase of the process cycle.

Download or read book Science and Technology for Disposal of Radioactive Tank Wastes written by Wallace W. Shulz and published by Springer Science & Business Media. This book was released on 2013-11-11 with total page 513 pages. Available in PDF, EPUB and Kindle. Book excerpt: Radioactive wastes resulting from over 40 years of production of nuclear weapons in the U. S. are currently stored in 273 underground tanks at the U. S. Department of Energy Hanford site, Idaho National Engineering and Environmental Laboratory, Oak Ridge Reservation, and Savannah River site. Combined, tanks at these sjtes contain approximately 94,000,000 gallons of waste in a variety of forms including liquid, concrete-like salt cake, and various sludges. More than 730,000,000 curies of several radioactive isotopes are present in the underground tanks. Certainly, one of the greatest challenges facing the U. S. Department of Energy is how to characterize, retrieve, treat, and immobilize the great variety of tank wastes in a safe, timely, and cost-effective manner. For several years now, the U. S. Department of Energy has initiated and sponsored scientific and engineering studies, tests, and demonstrations to develop the myriad of technologies required to dispose of the radioactive tank wastes. In recent times, much of the Department of Energy R&D activities concerning tank wastes have been closely coordinated and organized through the Tanks Focus Area (IF A); responsibility for technical operations of the TF A has been assigned to the Pacific Northwest National Laboratory.

Download or read book Macrocyclic Chemistry written by K. Gloe and published by Springer Science & Business Media. This book was released on 2005-12-05 with total page 450 pages. Available in PDF, EPUB and Kindle. Book excerpt: Macrocyclic Chemistry: Current Trends and Future Perspectives illustrates essential concepts in this expanding research field covering both basic and applied studies. Written by well-known experts from around the world, the topics of the chapters range from new macrocyclic architectures with different functions and self-assembly processes through to the modeling and dynamics of such systems. The content also reflects on application possibilities in analytical chemistry, separation processes, material preparation and medicine. Thus this book serves as a creative source of research strategies and methodic tools. Providing an excellent overview of the field, this book will be a valuable resource for researchers in industry and academic institutions as well as for teachers of science and graduate students. This book is devoted to the long-standing tradition of the International Symposia on Macrocyclic Chemistry (ISMC) and published to coincide with the 30th meeting, Dresden, Germany.

Download or read book Modeling of Crystalline Silicotitanate Ion Exchange Columns written by and published by . This book was released on 1999 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Non-elutable ion exchange is being considered as a potential replacement for the In-Tank Precipitation process for removing cesium from Savannah River Site (SRS) radioactive waste. Crystalline silicotitanate (CST) particles are the reference ion exchange medium for the process. A major factor in the construction cost of this process is the size of the ion exchange column required to meet product specifications for decontaminated waste. To validate SRS column sizing calculations, SRS subcontracted two reknowned experts in this field to perform similar calculations: Professor R.G. Anthony, Department of Chemical Engineering, Texas A & 038;M University, and Professor S.W. Wang, Department of Chemical Engineering, Purdue University. The appendices of this document contain reports from the two subcontractors. Definition of the design problem came through several meetings and conference calls between the participants and SRS personnel over the past few months. This document summarizes the problem definition and results from the two reports.

Download or read book Radioactive Waste Management and Contaminated Site Clean Up written by William E Lee and published by Elsevier. This book was released on 2013-10-31 with total page 925 pages. Available in PDF, EPUB and Kindle. Book excerpt: Radioactive waste management and contaminated site clean-up reviews radioactive waste management processes, technologies, and international experiences. Part one explores the fundamentals of radioactive waste including sources, characterisation, and processing strategies. International safety standards, risk assessment of radioactive wastes and remediation of contaminated sites and irradiated nuclear fuel management are also reviewed. Part two highlights the current international situation across Africa, Asia, Europe, and North America. The experience in Japan, with a specific chapter on Fukushima, is also covered. Finally, part three explores the clean-up of sites contaminated by weapons programmes including the USA and former USSR.Radioactive waste management and contaminated site clean-up is a comprehensive resource for professionals, researchers, scientists and academics in radioactive waste management, governmental and other regulatory bodies and the nuclear power industry. - Explores the fundamentals of radioactive waste including sources, characterisation, and processing strategies - Reviews international safety standards, risk assessment of radioactive wastes and remediation of contaminated sites and irradiated nuclear fuel management - Highlights the current international situation across Africa, Asia, Europe, and North America specifically including a chapter on the experience in Fukushima, Japan

Download or read book Waste Forms Technology and Performance written by National Research Council and published by National Academies Press. This book was released on 2011-09-05 with total page 308 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Department of Energy's Office of Environmental Management (DOE-EM) is responsible for cleaning up radioactive waste and environmental contamination resulting from five decades of nuclear weapons production and testing. A major focus of this program involves the retrieval, processing, and immobilization of waste into stable, solid waste forms for disposal. Waste Forms Technology and Performance, a report requested by DOE-EM, examines requirements for waste form technology and performance in the cleanup program. The report provides information to DOE-EM to support improvements in methods for processing waste and selecting and fabricating waste forms. Waste Forms Technology and Performance places particular emphasis on processing technologies for high-level radioactive waste, DOE's most expensive and arguably most difficult cleanup challenge. The report's key messages are presented in ten findings and one recommendation.

Download or read book Molecular Modeling Investigation of Cation Siting in Crystalline Silicotitanate and Polyoxoniobate Materials written by and published by . This book was released on 2004 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: Separation of radionuclides from high-level nuclear waste solutions is a vital step to minimize the amount of nuclear waste volume for final disposal. A number of inorganic ion exchangers have demonstrated the ability to selectively remove low concentrations of radionuclides in the presence of high sodium ion content and alkalinity. Various classes of crystalline silicotitanates (CST), pharmacosiderates and polyoxoniobates are being synthesized by collaborators at Texas A & M and Sandia National Laboratories. The ion exchange performance of these materials may be improved by introducing suitable structural modifications, such as partial substitution of niobium for titanium in the framework structures. In this work, the origins of ion exchange selectivity and kinetics are investigated through atomistic level simulations. The primary focus has been to develop a transferable potential model that can be used to accurately predict structural characteristics of the ion exchangers o f interest. Energy minimizations and molecular dynamics simulations are applied to the CST and polyoxoniobate materials. Structural characteristics, such as cation and water sites, coordinating environments and the energetics associated with the sites are determined, providing additional molecular-level insight into the stability of the structures.

Download or read book Materialien zum Rechtsanw lte und Patentanw lteberufsrechts nderungsgesetz written by and published by . This book was released on 1988 with total page 404 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book LITERATURE REVIEWS TO SUPPORT ION EXCHANGE TECHNOLOGY SELECTION FOR MODULAR SALT PROCESSING written by and published by . This book was released on 2007 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This report summarizes the results of literature reviews conducted to support the selection of a cesium removal technology for application in a small column ion exchange (SCIX) unit supported within a high level waste tank. SCIX is being considered as a technology for the treatment of radioactive salt solutions in order to accelerate closure of waste tanks at the Savannah River Site (SRS) as part of the Modular Salt Processing (MSP) technology development program. Two ion exchange materials, spherical Resorcinol-Formaldehyde (RF) and engineered Crystalline Silicotitanate (CST), are being considered for use within the SCIX unit. Both ion exchange materials have been studied extensively and are known to have high affinities for cesium ions in caustic tank waste supernates. RF is an elutable organic resin and CST is a non-elutable inorganic material. Waste treatment processes developed for the two technologies will differ with regard to solutions processed, secondary waste streams generated, optimum column size, and waste throughput. Pertinent references, anticipated processing sequences for utilization in waste treatment, gaps in the available data, and technical comparisons will be provided for the two ion exchange materials to assist in technology selection for SCIX. The engineered, granular form of CST (UOP IE-911) was the baseline ion exchange material used for the initial development and design of the SRS SCIX process (McCabe, 2005). To date, in-tank SCIX has not been implemented for treatment of radioactive waste solutions at SRS. Since initial development and consideration of SCIX for SRS waste treatment an alternative technology has been developed as part of the River Protection Project Waste Treatment Plant (RPP-WTP) Research and Technology program (Thorson, 2006). Spherical RF resin is the baseline media for cesium removal in the RPP-WTP, which was designed for the treatment of radioactive waste supernates and is currently under construction in Hanford, WA. Application of RF for cesium removal in the Hanford WTP does not involve in-riser columns but does utilize the resin in large scale column configurations in a waste treatment facility. The basic conceptual design for SCIX involves the dissolution of saltcake in SRS Tanks 1-3 to give approximately 6 M sodium solutions and the treatment of these solutions for cesium removal using one or two columns supported within a high level waste tank. Prior to ion exchange treatment, the solutions will be filtered for removal of entrained solids. In addition to Tanks 1-3, solutions in two other tanks (37 and 41) will require treatment for cesium removal in the SCIX unit. The previous SCIX design (McCabe, 2005) utilized CST for cesium removal with downflow supernate processing and included a CST grinder following cesium loading. Grinding of CST was necessary to make the cesium-loaded material suitable for vitrification in the SRS Defense Waste Processing Facility (DWPF). Because RF resin is elutable (and reusable) and processing requires conversion between sodium and hydrogen forms using caustic and acidic solutions more liquid processing steps are involved. The WTP baseline process involves a series of caustic and acidic solutions (downflow processing) with water washes between pH transitions across neutral. In addition, due to resin swelling during conversion from hydrogen to sodium form an upflow caustic regeneration step is required. Presumably, one of these basic processes (or some variation) will be utilized for MSP for the appropriate ion exchange technology selected. CST processing involves two primary waste products: loaded CST and decontaminated salt solution (DSS). RF processing involves three primary waste products: spent RF resin, DSS, and acidic cesium eluate, although the resin is reusable and typically does not require replacement until completion of multiple treatment cycles. CST processing requires grinding of the ion exchange media, handling of solids with high cesium loading, and handling of liquid wash and conditioning solutions. RF processing requires handling and evaporation of cesium eluates, disposal of spent organic resin, and handling of the various liquid wash and regenerate solutions used. In both cases, the DSS will be immobilized in a low activity waste form. It appears that both technologies are mature, well studied, and generally suitable for this application. Technology selection will likely be based on downstream impacts or preferences between the various processing options for the two materials rather than on some unacceptable performance property identified for one material. As a result, the following detailed technical review and summary of the two technologies should be useful to assist in technology selection for SCIX.

Download or read book Advanced Separation Techniques for Nuclear Fuel Reprocessing and Radioactive Waste Treatment written by Kenneth L Nash and published by Elsevier. This book was released on 2011-03-15 with total page 513 pages. Available in PDF, EPUB and Kindle. Book excerpt: Advanced separations technology is key to closing the nuclear fuel cycle and relieving future generations from the burden of radioactive waste produced by the nuclear power industry. Nuclear fuel reprocessing techniques not only allow for recycling of useful fuel components for further power generation, but by also separating out the actinides, lanthanides and other fission products produced by the nuclear reaction, the residual radioactive waste can be minimised. Indeed, the future of the industry relies on the advancement of separation and transmutation technology to ensure environmental protection, criticality-safety and non-proliferation (i.e., security) of radioactive materials by reducing their long-term radiological hazard.Advanced separation techniques for nuclear fuel reprocessing and radioactive waste treatment provides a comprehensive and timely reference on nuclear fuel reprocessing and radioactive waste treatment. Part one covers the fundamental chemistry, engineering and safety of radioactive materials separations processes in the nuclear fuel cycle, including coverage of advanced aqueous separations engineering, as well as on-line monitoring for process control and safeguards technology. Part two critically reviews the development and application of separation and extraction processes for nuclear fuel reprocessing and radioactive waste treatment. The section includes discussions of advanced PUREX processes, the UREX+ concept, fission product separations, and combined systems for simultaneous radionuclide extraction. Part three details emerging and innovative treatment techniques, initially reviewing pyrochemical processes and engineering, highly selective compounds for solvent extraction, and developments in partitioning and transmutation processes that aim to close the nuclear fuel cycle. The book concludes with other advanced techniques such as solid phase extraction, supercritical fluid and ionic liquid extraction, and biological treatment processes.With its distinguished international team of contributors, Advanced separation techniques for nuclear fuel reprocessing and radioactive waste treatment is a standard reference for all nuclear waste management and nuclear safety professionals, radiochemists, academics and researchers in this field. - A comprehensive and timely reference on nuclear fuel reprocessing and radioactive waste treatment - Details emerging and innovative treatment techniques, reviewing pyrochemical processes and engineering, as well as highly selective compounds for solvent extraction - Discusses the development and application of separation and extraction processes for nuclear fuel reprocessing and radioactive waste treatment

Download or read book Materials for Nuclear Waste Immobilization written by Michael I. Ojovan and published by MDPI. This book was released on 2020-01-09 with total page 220 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book outlines recent advances in nuclear wasteform materials including glasses, ceramics and cements and spent nuclear fuel. It focuses on durability aspects and contains data on performance of nuclear wasteforms as well as expected behavior in a disposal environment.

Download or read book Comparison of Organic and Inorganic Ion Exchangers for Removal of Cesium and Strontium from Simulated and Actual Hanford 241 AW 101 DSSF Tank Waste written by and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A number of organic and inorganic exchangers are being developed and evaluated for cesium removal from Hanford tank wastes. The exchangers of interest that are investigated in this work include powdered (IONSIV[reg-sign] IE-910; referred to as IE-910) and engineered (IONSIV[reg-sign] IE-911; referred to as IE-911) forms of the crystalline silico-titanate (CST) inorganic sorbent developed by Sandia National Laboratories (SNL)/Texas A and M and prepared by UOP; a phenol-formaldehyde (CS-100) resin developed by Rohm and Haas; a resorcinol-formaldehyde (R-F) polymer developed at the Westinghouse Savannah River Company (WSRC) and produced by Boulder Scientific; an inorganic zeolite exchanger produced by UOP (IONSIV[reg-sign] TIE-96; referred to as TIE-96); an inorganic sodium titanate produced by Allied Signal/Texas A and M (NaTi); and a macrocyclic organic resin developed and produced by IBC Advanced Technologies (SuperLig[reg-sign] 644; referred to as SL-644). Several of these materials are still under development and may not be in the optimal form. The work described in this report involves the direct comparison of the ion exchange materials for the pretreatment of actual and simulated Hanford tank waste. Data on the performance of all of the exchangers with simulated and actual double shell slurry feed (DSSF) is included. The DSSF waste is a mixture of the supernate from tanks 101-AW (70%), 106-AP (20%) and 102-AP (10%). The comparative parameters include radionuclide removal efficiency under a variety of conditions and material properties (e.g., bed density and percent removable water). Cesium and strontium distribution (K[sub d]), lambda ([lambda]= K[sub d][times][rho][sub b]), and decontamination factors (DF) are compared as a function of exchanger contact duration, solution composition (Na and Cs concentration), exchanger/waste phase ratio, and multiple sequential contacts.

Download or read book Modeling of Crystalline Silicotitanate Ion Exchange Columns Using Experimental Data from SRS Simulated Waste written by and published by . This book was released on 1999 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: Non-elutable ion exchange using crystalline silicotitanate is being considered for removing cesium from Savannah River Site radioactive waste. The construction cost of this process depends strongly on the size of the ion exchange column required to meet product specifications.

Download or read book Design Optimization and Selectivity of Inorganic Ion exchangers for Radioactive Waste Remediation written by Dmitry Gennadievich Medvedev and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The processes of development of nuclear weapons resulted in accumulation of thousands of curies of high-level radioactive waste. Liquid waste produced in the US has been stored in carbon steel tanks in highly alkaline (1-3 M NaOH, 6 M sodium salts) media for fifty years and leakage has occurred. One of the approaches to the solution of the problem of radioactive waste is to adsorb the nuclides on highly selective ion-exchange material, solidify in a glass matrix and dispose in a geological formation. The use of the ion-exchange technology is limited by the time of the sorbent-solution contact required to reduce the activity of the streams to acceptable levels. Inorganic ion-exchangers are promising materials due to their high radiation stability, extreme selectivity, and compatibility with the glass matrix. The contact time can be reduced by improving selectivities, kinetics, and capacities of the materials towards the target ions. This can be accomplished in part through understanding of the origin of ion-exchange selectivity. Crystalline zeotypes with minerals sitinakite (ideal formula Na2Ti2O3SiO4·2H2O) and pharmacosiderite (HM3(TO)4(GeO4)[subscript]x(SiO4)3[subscript]x M = Cs, Na, K+, T=Nb5+, Ge4+, Ti4+) structures are excellent candidates for selectivity studies because of their ion-exchange properties tunable by alterations of synthetic procedures, and isomorphous framework substitution. The Nb-substitution in titanium sites reduces the framework charge, whereas Ge substitution decreases the unit cell size if in titanium sites and increases if it in silicon sites. The compounds were hydrothermally synthesized in Ti/Si, Ti/Nb/Si, Ti/Ge/Si forms and characterized by structural and ion-exchange studies. The 25% Nb substitution in titanosilicate sitinakite resulted in enhanced selectivity for cesium and additional bond formation of cesium within the channel. The selectivity for cesium in germanium substituted pharmacosiderite also was correlated with the coordination environment within the channel. In the advanced stages of this study semi-crystalline (sodium nonatitanate) and amorphous (monosodium titanate) materials also were considered because of their remarkable strontium selectivity. In situ X-ray diffraction techniques revealed that the sodium nonatitanate precedes the formation of the TS phase in hydrothermal synthesis. This knowledge allowed us to design and synthesize material for combined cesium and strontium removal.

Download or read book Vitrification of Ion Exchange Materials Innovative Technology Summary Report written by and published by . This book was released on 1999 with total page 23 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Department of Energy is responsible for removing and immobilizing radioactive waste from the underground tanks at the Savannah River Site, Oak Ridge Reservation, Idaho National Engineering and Environmental Laboratory, and Hanford Site. The waste contains highly radioactive cesium which must be removed from the low activity fraction of the waste and vitrified with the high level waste. Crystalline silicotitanate, a highly selective inorganic ion exchange material was developed to remove cesium from liquid tank wastes. Crystalline silicotitanate is non-regenerable. One alternative is to vitrify the cesium-loaded crystalline silicotitanate and dispose of it in high level waste glass. Glass formulations were developed and pilot scale vitrification runs have been conducted. Ten gallons of loaded crystalline silicotitanate from the Cesium Removal Demonstration at Oak Ridge Reservation were vitrified at the Savannah River Site in 1997.