Download or read book Fundamental Chemistry Characterization and Separation of Technetium Complexes in Hanford Waste written by and published by . This book was released on 2000 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: The ultimate goal of this project is to separate technetium from Hanford tank waste. Our prior work with Hanford waste has shown that a large portion of the technetium in some tanks is not pertechnetate (TcOd) and is not easily oxidized to it. This has serious repercussions for technetium partitioning schemes because they are designed to separate this chemical form. Rational attempts to oxidize these species to Tc04* for processing or to separate the non-pertechnetate species themselves would be facilitated by knowing the identity of these 5 complexes and understanding their fundamental chemistry. Tank characterization work has not yet identified any of the non-pertechnetate species. However, based on the types of ligands available and the redox conditions in the tank, a reasonable speculation can be made about the types of species that may be present. 3 Thus, this project was synthesizing relevant model complexes of Tc(III), Tc(IV), and Tc(V) that may form under tank waste conditions. The complexes were to be characterized and used as standards for characterizing the nonpertechnetate species in actual waste using instrumental techniques such as XAS and subsequent EXAFS and XANES analysis. We had hoped to study the redox chemistry of the technetium complexes so that more efficient and selective oxidative methods can be used to bring the tank non-pertechnetate species to TcOd for processing purposes. We were to study the ligand substitution chemistry of the synthesized complexes, which could be used to develop separation methods for non-pertechnetate species. Understanding the fundamental chemistry of these technetium complexes hopefully will enable technetium to be efficiently removed from the Hanford tank waste and help DOE to fulfill its remediation mission.

Download or read book Statut der Lehrlingskrankenkasse bei der Genossenschaft der in written by and published by . This book was released on 1918 with total page 17 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Identification of Non Pertechnetate Species in Hanford Tank Waste Their Synthesis Characterization and Fundamental Chemistry written by and published by . This book was released on 2002 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: Technetium, as pertechnetate (TcO4 - ), is a mobile species in the environment. This characteristic, along with its long half-life, (99Tc, t1/2 = 213,000 a) makes technetium a major contributor to the long-term hazard associated with low level waste (LLW) disposal. Technetium partitioning from the nuclear waste at DOE sites will be required so that the LLW forms meet DOE performance assessment criteria. Technetium separations assume that technetium exists as TcO4 - in the waste. However, years of thermal, chemical, and radiolytic digestion in the presence of organic material, has transformed much of the TcO4 - into unidentified, stable, reduced, technetium complexes. To successfully partition technetium from tank wastes, it will be necessary to either remove these technetium species with a new process, or reoxidize them to TcO4 - so that conventional pertechnetate separation schemes will be successful.

Download or read book Research Needs for High Level Waste Stored in Tanks and Bins at U S Department of Energy Sites written by National Research Council and published by National Academies Press. This book was released on 2001-10-05 with total page 146 pages. Available in PDF, EPUB and Kindle. Book excerpt: The United States Department of Energy (DOE) has approximately 400 million liters (100 million gallons) of liquid high-level waste (HLW) stored in underground tanks and approximately 4,000 cubic meters of solid HLW stored in bins. The current DOE estimate of the cost of converting these liquid and solid wastes into stable forms for shipment to a geological repository exceeds $50 billion to be spent over several decades (DOE, 2000). The Committee on Long-Term Research Needs for Radioactive High-Level Waste at Department of Energy Sites was appointed by the National Research Council (NRC) to advise the Environmental Management Science Program (EMSP) on a long-term research agenda addressing the above problems related to HLW stored in tanks and bins at DOE sites.

Download or read book Technetium Chemistry in High Level Waste written by Nancy J. Hess and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Tc contamination is found within the DOE complex at those sites whose mission involved extraction of plutonium from irradiated uranium fuel or isotopic enrichment of uranium. At the Hanford Site, chemical separations and extraction processes generated large amounts of high level and transuranic wastes that are currently stored in underground tanks. The waste from these extraction processes is currently stored in underground High Level Waste (HLW) tanks. However, the chemistry of the HLW in any given tank is greatly complicated by repeated efforts to reduce volume and recover isotopes. These processes ultimately resulted in mixing of waste streams from different processes. As a result, the chemistry and the fate of Tc in HLW tanks are not well understood. This lack of understanding has been made evident in the failed efforts to leach Tc from sludge and to remove Tc from supernatants prior to immobilization. Although recent interest in Tc chemistry has shifted from pretreatment chemistry to waste residuals, both needs are served by a fundamental understanding of Tc chemistry.

Download or read book Engineering Separations Unit Operations for Nuclear Processing written by Reid Peterson and published by CRC Press. This book was released on 2019-11-15 with total page 261 pages. Available in PDF, EPUB and Kindle. Book excerpt: Engineering Separations Unit Operations for Nuclear Processing provides insight into the fundamentals of separations in nuclear materials processing not covered in typical texts. This book integrates fuel cycle and waste processing into a single, coherent approach, demonstrating that the principles from one field can and should be applied to the other. It provides historical perspectives on nuclear materials processing, current assessment and challenges, and how past challenges were overcome. It also provides understanding of the engineering principles associated with handling nuclear materials. This book is aimed at researchers, graduate students, and professionals in the fields of chemical engineering, mechanical engineering, nuclear engineering, and materials engineering.

Download or read book Review of the Final Draft Analysis of Supplemental Treatment Approaches of Low Activity Waste at the Hanford Nuclear Reservation written by National Academies of Sciences, Engineering, and Medicine and published by National Academies Press. This book was released on 2019-09-15 with total page 81 pages. Available in PDF, EPUB and Kindle. Book excerpt: In 1943, as part of the Manhattan Project, the Hanford Nuclear Reservation was established with the mission to produce plutonium for nuclear weapons. During 45 years of operations, the Hanford Site produced about 67 metric tonnes of plutoniumâ€"approximately two-thirds of the nation's stockpile. Production processes generated radioactive and other hazardous wastes and resulted in airborne, surface, subsurface, and groundwater contamination. Presently, 177 underground tanks contain collectively about 210 million liters (about 56 million gallons) of waste. The chemically complex and diverse waste is difficult to manage and dispose of safely. Section 3134 of the National Defense Authorization Act for Fiscal Year 2017 calls for a Federally Funded Research and Development Center (FFRDC) to conduct an analysis of approaches for treating the portion of low-activity waste at the Hanford Nuclear Reservation intended for supplemental treatment. The third of four, this report provides an overall assessment of the FFRDC team's final draft report, dated April 5, 2019.

Download or read book Technetium Chemistry in HLW written by Nancy J. Hess and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Tc contamination is found within the DOE complex at those sites whose mission involved extraction of plutonium from irradiated uranium fuel or isotopic enrichment of uranium. At the Hanford Site, chemical separations and extraction processes generated large amounts of high level and transuranic wastes that are currently stored in underground tanks. The waste from these extraction processes is currently stored in underground High Level Waste (HLW) tanks. However, the chemistry of the HLW in any given tank is greatly complicated by repeated efforts to reduce volume and recover isotopes. These processes ultimately resulted in mixing of waste streams from different processes. As a result, the chemistry and the fate of Tc in HLW tanks are not well understood. This lack of understanding has been made evident in the failed efforts to leach Tc from sludge and to remove Tc from supernatants prior to immobilization. Although recent interest in Tc chemistry has shifted from pretreatment chemistry to waste residuals, both needs are served by a fundamental understanding of Tc chemistry.

Download or read book Research Program to Investigate the Fundamental Chemistry of Technetium 1998 Annual Progress Report written by and published by . This book was released on 1998 with total page 3 pages. Available in PDF, EPUB and Kindle. Book excerpt: Technetium (99Tc, [beta] emitter, half-life 2.1 x 105 years, spA= 1.7 x 10−2 Ci/g) is one of the radionuclides of major concern because of regulatory considerations for radioactive waste disposal. The propensity of Tc as pertechnetate, TcO4−, to migrate in the geosphere necessitates its safe, long-term immobilization. Technetium is found in the nuclear waste storage tanks at the Hanford and at the Savannah River sites in highly alkaline environments along with multi-molar concentrations of nitrate, nitrite, and Na ions and lesser amounts of organic complexants, phosphate, sulfate chloride, fluoride, and carbonate. It has been assumed that technetium is present in the waste tanks as the pertechnetate ion but a recent study has suggested that at least in part, technetium is present in another form. There is a lack of information on Tc chemistry in oxidation states III-V with simple inorganic (OH−, CO32−, PO43−, SiO44−) and common organic ligands (EDTA, citrate, oxalate) under alkaline conditions. This is essential information needed for pretreatment schemes, processing, and the assessment of stability of Tc in waste form materials. Further complicating the Tc waste tank chemistry is the added effect of an intense radiation field originating from 137Cs and 9°Sr. The interactions of the ionizing radiation with water, nitrate, nitrite, and other minor components create highly reactive species that can strongly perturb the oxidation-reduction conditions. The stability of Tc in waste form materials is of paramount importance for long term storage concerns and the solid state chemical properties of many candidate Tc compounds are unknown. There have been few systematic studies of Tc stability in lower valent solids with the exception of TcO2. Thus, it is not possible at present to assess the long term stability of many Tc compounds relevant to proposed waste form materials. This experimental research program addresses the characterization of the chemistry of technetium pertinent to the waste tank environment and to various waste forms. The solution and solid state chemistry of this element will be studied in aqueous solutions as a function of pH with the various salts added such as nitrate and nitrite, and as a function of radiation dose. The second part of this program is a search for stable, lower valent Tc materials which may prove useful for waste storage. This report summarizes the results after nine months of a three year project.

Download or read book Research Program to Investigate the Fundamental Chemistry of Technetium written by and published by . This book was released on 2001 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: Technetium (99Tc, half-life = 2.13x105 years, b-emitter) is one of the radionuclides of major concern for nuclear waste disposal. This concern is due to the long half-life of 99Tc, the ease with which pertechnetate, TcO4 -, migrates in the geosphere, difficulties in incorporating technetium into glass waste forms, and the corresponding regulatory considerations. The problem of mobility of pertechnetate in the environment is compounded by the fact that pertechnetate is the thermodynamically stable form of technetium in oxidizing environments. Because of this stability, pertechnetate was presumed to be the predominant chemical form of technetium in the aqueous phase of nuclear waste tanks. However, studies have indicated that a significant fraction of the technetium is in a different chemical form. These factors present challenges the separation and immobilization of technetium. The objective of this project is to investigate the chemical behavior of technetium so that the se problems may be understood and the challenges addressed.

Download or read book Chemical Separation Technologies and Related Methods of Nuclear Waste Management written by Gregory R. Choppin and published by Springer Science & Business Media. This book was released on 1999-02-28 with total page 324 pages. Available in PDF, EPUB and Kindle. Book excerpt: Separation technologies are of crucial importance to the goal of significantly reducing the volume of high-level nuclear waste, thereby reducing the long-term health risks to mankind. International co-operation, including the sharing of concepts and methods, as well as technology transfer, is essential in accelerating research and development in the field. The writers of this book are all internationally recognised experts in the field of separation technology, well qualified to assess and criticize the current state of separation research as well as to identify future opportunities for the application of separation technologies to the solution of nuclear waste management problems. The major emphases in the book are research opportunities in the utilization of innovative and potentially more efficient and cost effective processes for waste processing/treatment, actinide speciation/separation methods, technological processing, and environmental restoration.

Download or read book An End State Methodology for Identifying Technology Needs for Environmental Management with an Example from the Hanford Site Tanks written by Committee on Technologies for Cleanup of High-Level Waste in Tanks in the DOE Weapons Complex and published by National Academies Press. This book was released on 1999-03-30 with total page 105 pages. Available in PDF, EPUB and Kindle. Book excerpt: A major issue in the cleanup of this country's nuclear weapons complex is how to dispose of the radioactive waste resulting primarily from the chemical processing operations for the recovery of plutonium and other defense strategic nuclear materials. The wastes are stored in hundreds of large underground tanks at four U.S. Department of Energy (DOE) sites throughout the United States. The tanks contain hundreds of thousands of cubic meters of radioactive and hazardous waste. Most of it is high-level waste (HLW), some of it is transuranic (TRU) or low- level waste (LLW), and essentially all containing significant amounts of chemicals deemed hazardous. Of the 278 tanks involved, about 70 are known or assumed to have leaked some of their contents to the environment. The remediation of the tanks and their contents requires the development of new technologies to enable cleanup and minimize costs while meeting various health, safety, and environmental objectives. While DOE has a process based on stakeholder participation for screening and formulating technology needs, it lacks transparency (in terms of being apparent to all concerned decision makers and other interested parties) and a systematic basis (in terms of identifying end states for the contaminants and developing pathways to these states from the present conditions). An End State Methodology for Identifying Technology Needs for Environmental Management, with an Example from the Hanford Site Tanks describes an approach for identifying technology development needs that is both systematic and transparent to enhance the cleanup and remediation of the tank contents and their sites. The authoring committee believes that the recommended end state based approach can be applied to DOE waste management in general, not just to waste in tanks. The approach is illustrated through an example based on the tanks at the DOE Hanford Site in southeastern Washington state, the location of some 60 percent by volume of the tank waste residues.

Download or read book Final Review of the Study on Supplemental Treatment Approaches of Low Activity Waste at the Hanford Nuclear Reservation written by National Academies of Sciences, Engineering, and Medicine and published by National Academies Press. This book was released on 2020-03-30 with total page 131 pages. Available in PDF, EPUB and Kindle. Book excerpt: The U.S. Department of Energy's Office of Environmental Management is responsible for managing and cleaning up the waste and contamination at the Hanford Nuclear Reservation, the nation's biggest and most complex nuclear cleanup challenge. At the site, 177 underground tanks collectively contain about 211 million liters of waste that includes high-activity and low-activity materials. At the request of Congress, Final Review of the Study on Supplemental Treatment Approaches of Low-Activity Waste at the Hanford Nuclear Reservation: Review #4 focuses on approaches for treatment and disposal of the supplemental portion of the low-activity waste from the tanks. This review report discusses developments since the publication of Review #3 and provides a summary of public comments on the third committee review report. The authoring committee then shares their views on these comments and whether they change any of the findings or recommendations in the third review report.

Download or read book Energy Research Abstracts written by and published by . This book was released on 1994-08 with total page 442 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Research Program to Investigate the Fundamental Chemistry of Technetium written by Carol J. Burns and published by . This book was released on 2003 with total page 55 pages. Available in PDF, EPUB and Kindle. Book excerpt: The objective of this research is to increase the knowledge of the fundamental technetium chemistry that is necessary to address challenges to the safe, long-term remediation of high-level waste posed by this element. These challenges may be divided into two categories: unexpected behavior of technetium in high-level waste tanks at the Hanford and Savannah River Sites and the behavior of technetium in waste forms.

Download or read book Separation Concentration and Immobilization of Technetium and Iodine from Alkaline Supernate Waste written by and published by . This book was released on 1998 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Development of remediation technologies for the characterization, retrieval, treatment, concentration, and final disposal of radioactive and chemical tank waste stored within the Department of Energy (DOE) complex represents an enormous scientific and technological challenge. A combined total of over 90 million gallons of high-level waste (HLW) and low-level waste (LLW) are stored in 335 underground storage tanks at four different DOE sites. Roughly 98% of this waste is highly alkaline in nature and contains high concentrations of nitrate and nitrite salts along with lesser concentrations of other salts. The primary waste forms are sludge, saltcake, and liquid supernatant with the bulk of the radioactivity contained in the sludge, making it the largest source of HLW. The saltcake (liquid waste with most of the water removed) and liquid supernatant consist mainly of sodium nitrate and sodium hydroxide salts. The main radioactive constituent in the alkaline supernatant is cesium-137, but strontium-90, technetium-99, and transuranic nuclides are also present in varying concentrations. Reduction of the radioactivity below Nuclear Regulatory Commission (NRC) limits would allow the bulk of the waste to be disposed of as LLW. Because of the long half-life of technetium-99 (2.1 x 10 5 y) and the mobility of the pertechnetate ion (TcO 4 - ) in the environment, it is expected that technetium will have to be removed from the Hanford wastes prior to disposal as LLW. Also, for some of the wastes, some level of technetium removal will be required to meet LLW criteria for radioactive content. Therefore, DOE has identified a need to develop technologies for the separation and concentration of technetium-99 from LLW streams. Eichrom has responded to this DOE-identified need by demonstrating a complete flowsheet for the separation, concentration, and immobilization of technetium (and iodine) from alkaline supernatant waste.

Download or read book Handbook of Radioactivity Analysis written by Michael F. L'Annunziata and published by Academic Press. This book was released on 2012-09-01 with total page 1419 pages. Available in PDF, EPUB and Kindle. Book excerpt: The updated and much expanded 3e of the Handbook of Radioactivity Analysis is an authoritative reference providing the principles, practical techniques, and procedures for the accurate measurement of radioactivity from the very low levels encountered in the environment to higher levels measured in radioisotope research, clinical laboratories, biological sciences, radionuclide standardization, nuclear medicine, nuclear power, and fuel cycle facilities and in the implementation of nuclear forensic analysis and nuclear safeguards. The book describes the basic principles of radiation detection and measurement and the preparation of samples from a wide variety of matrices, assists the investigator or technician in the selection and use of appropriate radiation detectors, and presents state-of-the-art methods of analysis. Fundamentals of radiation properties, radionuclide decay, the calculations involved, and methods of detection provide the basis for a thorough understanding of the analytical procedures. The Handbook of Radioactivity Analysis, 3e, is suitable as a teaching text for university and professional training courses. - The only comprehensive reference that describes the principles of detection and practical applications of every type of radioactivity detector currently used. The new 3e is broader in scope, with revised and expanded chapters, new authors, and seven new chapters on Alpha Spectrometry, Radionuclide Standardization, Radioactive Aerosol Measurements, Environmental Radioactivity Monitoring, Marine Radioactivity Analysis, Nuclear Forensic Analysis and Analytical Techniques in Nuclear Safeguards - Discusses in detail the principles, theory and practice applied to all types of radiation detection and measurement, making it useful for both teaching and research