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Processing Of Leu Targets For 99mo Production Dissolution Of Metal Foil Targets By Alkaline Hydrogen Peroxide
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Book Synopsis Processing of LEU Targets for 99Mo Production -- Dissolution of Metal Foil Targets by Alkaline Hydrogen Peroxide by :
Download or read book Processing of LEU Targets for 99Mo Production -- Dissolution of Metal Foil Targets by Alkaline Hydrogen Peroxide written by and published by . This book was released on 1995 with total page 11 pages. Available in PDF, EPUB and Kindle. Book excerpt: In FY 1995, the authors started studies on a new process for dissolution of low-enriched uranium (LEU) targets for 99Mo production. In this process, an LEU metal foil target is dissolved in a mixture of sodium hydroxide and hydrogen peroxide, then 99Mo is recovered from the dissolved solution. They focused on the dissolution kinetics to develop a mechanistic model for predicting the products and the rate of uranium dissolution under process conditions. They thoroughly studied the effects of hydrogen peroxide concentration, sodium hydroxide concentration, and temperature on the rate of uranium dissolution. It was found that uranium dissolution can be classified into a low-base (0.2M) and a high-base ( 0.2M) process. In the low-base process, both the equilibrium hydrogen peroxide and hydroxide concentrations affect the rate of uranium dissolution; in the high base process, uranium dissolution is a 0.25th order reaction with respect to the equilibrium hydrogen peroxide. The dissolution activation energy was experimentally determined to be 48.8 kJ/mol. Generally, the rate of uranium dissolution increases to a maximum as the hydroxide concentration is increased from 0.01 to about 1.5M, then it decreases as the hydroxide concentration is further increased. The alkalinity of the dissolution solution is an important factor that affects not only the dissolution rate, but also the amount of radioactive waste.
Book Synopsis Processing of LEU Targets for 99Mo Production by :
Download or read book Processing of LEU Targets for 99Mo Production written by and published by . This book was released on 1995 with total page 9 pages. Available in PDF, EPUB and Kindle. Book excerpt: Low-enriched uranium silicide targets designed to recover fission product 99Mo were dissolved in alkaline hydrogen peroxide (H2O2 plus NaOH) at about 90C. Sintering of matrix aluminum powder during irradiation and heat treatment retarded aluminum dissolution and prevented silicide particle dispersion. Gas evolved during dissolution is suspected to adhere to particles and block hydroxide ion contact with aluminum. Reduction of base concentrations from 5M to O.lM NaOH yielded similar silicide dissolution and peroxide destruction rates, simplifying later processing. Future work in particle dispersion enhancement, 99Mo separation, and waste disposal is also discussed.
Book Synopsis Processing of LEU Targets for 99Mo Production-dissolution of U3Si2 Targets by Alkaline Hydrogen Peroxide by : B. A. Buchholz
Download or read book Processing of LEU Targets for 99Mo Production-dissolution of U3Si2 Targets by Alkaline Hydrogen Peroxide written by B. A. Buchholz and published by . This book was released on 1995* with total page 10 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Processing of LEU Targets for 99Mo Production -- Dissolution of Metal Foils by Nitric-acid by :
Download or read book Processing of LEU Targets for 99Mo Production -- Dissolution of Metal Foils by Nitric-acid written by and published by . This book was released on 1995 with total page 17 pages. Available in PDF, EPUB and Kindle. Book excerpt: The first step in processing low-enriched uranium (LEU) targets for production of 99Mo is to dissolve the neutron-irradiated uranium foil coming from the reactor. Appropriate conditions for dissolving the foils were determined by measuring the dissolution rates for uranium foil over a wide range of temperatures and acid concentrations. On the basis of these dissolution rates, the process chemistry, and a model that integrates dissolution rates as a function of temperature and composition, a closed stainless-steel dissolver was designed, built, and tested for dissolving up to 18 g of uranium foil. The results were quite successful, with the uranium foil being dissolved within one hour as desired. To do this, the dissolver temperature must be in the range from 97 to 102 C, and the dissolver solution (cocktail) must have a composition of 3M nitric acid and 2M sulfuric acid. The final dissolver solution is subsequently processed to separate 99Mo from uranium, fission products, and other elements.
Book Synopsis Modification of Base-side 99MO Production Processes for LEU Metal-foil Targets by :
Download or read book Modification of Base-side 99MO Production Processes for LEU Metal-foil Targets written by and published by . This book was released on 1999 with total page 13 pages. Available in PDF, EPUB and Kindle. Book excerpt: Argonne National Laboratory is cooperating with the National Atomic Energy Commission of the Argentine Republic (CNEA) to convert their 99Mo production process, which uses high enriched uranium (HEU), to low-enriched uranium (LEU), The program is multifaceted; however, discussed in this paper are (1) results of laboratory experiments to develop means for substituting LEU metal-foil targets into the current process and (2) preparation of uranium-alloy or uranium-metal/aluminum-dispersion targets. Although 99Mo production is a multi-step process, the first two steps (target dissolution and primary molybdenum recovery) are by far the most important in the conversion. Commonly, once molybdenum is separated from the bulk of the uranium, the remainder of the process need not be modified. Our results show that up to this point in our study, conversion of the CNEA process to LEU appears viable.
Book Synopsis Development and Processing of LEU Targets for 99Mo Production by :
Download or read book Development and Processing of LEU Targets for 99Mo Production written by and published by . This book was released on 1997 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt: Most of the world's supply of {sup 99m}Tc for medical purposes is currently produced from the decay of 99Mo derived from the fissioning of high-enriched uranium (HEU). Substantial progress has been made in developing targets and chemical processes for producing 99Mo using low-enriched uranium (LEU). Target development has been focused on a uranium-metal foil target as a replacement for the coated-UO2 Cintichem-type target. Although the first designs were not successful because of ion mixing-induced bonding of the uranium foil to the target tubes, recent irradiations of modified targets have proven successful. Only minor modifications of the Cintichem chemical process are required for the uranium-metal foil targets. A demonstration using prototypically irradiated targets is anticipated in February 1997. Progress has also been made in basic dissolution of both uranium-metal foil and aluminum-clad U3Si2 dispersion fuel targets.
Book Synopsis Progress in Alkaline Peroxide Dissolution of Low-enriched Uranium Metal and Silicide Targets by :
Download or read book Progress in Alkaline Peroxide Dissolution of Low-enriched Uranium Metal and Silicide Targets written by and published by . This book was released on 1996 with total page 27 pages. Available in PDF, EPUB and Kindle. Book excerpt: This paper reports recent progress on two alkaline peroxide dissolution processes: the dissolution of low-enriched uranium metal and silicide (U3Si2) targets. These processes are being developed to substitute low-enriched for high-enriched uranium in targets used for production of fission-product 99Mo. Issues that are addressed include (1) dissolution kinetics of silicide targets, (2) 99Mo lost during aluminum dissolution, (3) modeling of hydrogen peroxide consumption, (4) optimization of the uranium foil dissolution process, and (5) selection of uranium foil barrier materials. Future work associated with these two processes is also briefly discussed.
Book Synopsis Progress in Chemical Processing of LEU Targets for 99Mo Production -- 1997 by :
Download or read book Progress in Chemical Processing of LEU Targets for 99Mo Production -- 1997 written by and published by . This book was released on 1997 with total page 20 pages. Available in PDF, EPUB and Kindle. Book excerpt: Presented here are recent experimental results of the continuing development activities associated with converting current processes for producing fission-product 99Mo from targets using high-enriched uranium (HEU) to low-enriched uranium (LEU). Studies were focused in four areas: (1) measuring the chemical behavior of iodine, rhodium, and silver in the LEU-modified Cintichem process, (2) performing experiments and calculations to assess the suitability of zinc fission barriers for LEU metal foil targets, (3) developing an actinide separations method for measuring alpha contamination of the purified 99Mo product, and (4) developing a cooperation with Sandia National Laboratories and Los Alamos National Laboratory that will lead to approval by the US Federal Drug Administration for production of 99Mo from LEU targets. Experimental results continue to show the technical feasibility of converting current HEU processes to LEU.
Book Synopsis Liste des pièces qui font foi de l'acceptation de la bulle "Unigenitus" dans tous les États catholiques by :
Download or read book Liste des pièces qui font foi de l'acceptation de la bulle "Unigenitus" dans tous les États catholiques written by and published by . This book was released on with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Gas Generation During Waste Treatment of Acidic Solutions from the Dissolution of Irradiated LEU Targets for 99Mo Production by :
Download or read book Gas Generation During Waste Treatment of Acidic Solutions from the Dissolution of Irradiated LEU Targets for 99Mo Production written by and published by . This book was released on 2017 with total page 46 pages. Available in PDF, EPUB and Kindle. Book excerpt: The goal of the Reduced Enrichment for Research and Test Reactors Program is to limit the use of high-enriched uranium (HEU) in research and test reactors by substituting low-enriched uranium (LEU) wherever possible. The work reported here documents our work to develop the calcining technologies and processes that will be needed for 99Mo production using LEU foil targets and the Modified Cintichem Process. The primary concern with the conversion to LEU from HEU targets is that it would result in a five- to six-fold increase in the total uranium. This increase results in more liquid waste from the process. We have been working to minimize the increase in liquid waste and to minimize the impact of any change in liquid waste. Direct calcination of uranium-rich nitric acid solutions generates NO2 gas and UO3 solid. We have proposed two processes for treating the liquid waste from a Modified Cintichem Process with a LEU foil. One is an optimized direct calcination process that is similar to the process currently in use. The other is a uranyl oxalate precipitation process. The specific goal of the work reported here was to characterize and compare the chemical reactions that occur during these two processes. In particular, the amounts and compositions of the gaseous and solid products were of interest. A series of experiments was carried out to show the effects of temperature and the redox potential of the reaction atmosphere. The primary products of the direct calcination process were mixtures of U3O8 and UO3 solids and NO2 gas. The primary products of the oxalate precipitation process were mixtures of U3O8 and UO2 solid and CO2 gas. Higher temperature and a reducing atmosphere tended to favor quadrivalent over hexavalent uranium in the solid product. These data will help producers to decide between the two processes. In addition, the data can be used to design appropriate off-gas systems for pilot and production facilities.
Book Synopsis Processing of LEU Targets for 99Mo Production--testing and Modification of the Cintichem Process by :
Download or read book Processing of LEU Targets for 99Mo Production--testing and Modification of the Cintichem Process written by and published by . This book was released on 1995 with total page 13 pages. Available in PDF, EPUB and Kindle. Book excerpt: Recent experimental results on testing and modification of the Cintichem process to allow substitution of low enriched uranium (LEU) for high enriched uranium (HEU) targets are presented in this report. The main focus is on 99Mo recovery and purification by its precipitation with [alpha]-benzoin oxime. Parameters that were studied include concentrations of nitric and sulfuric acids, partial neutralization of the acids, molybdenum and uranium concentrations, and the ratio of [alpha]-benzoin oxime to molybdenum. Decontamination factors for uranium, neptunium, and various fission products were measured. Experiments with tracer levels of irradiated LEU were conducted for testing the 99Mo recovery and purification during each step of the Cintichem process. Improving the process with additional processing steps was also attempted. The results indicate that the conversion of molybdenum chemical processing from HEU to LEU targets is possible.
Book Synopsis Progress in Chemical Treatment of LEU Targets by the Modified Cintichem Process by :
Download or read book Progress in Chemical Treatment of LEU Targets by the Modified Cintichem Process written by and published by . This book was released on 1996 with total page 29 pages. Available in PDF, EPUB and Kindle. Book excerpt: Presented here are recent experimental results on tests of a modified Cintichem process for producing 99Mo from low enriched uranium (LEU). Studies were focused in three areas: (1) testing the effects on 99Mo recovery and purity of dissolving LEU foil in nitric acid alone, rather than in the sulfuric/nitric acid mixture currently used, (2) measuring decontamination factors for radionuclide impurities in each purification step, and (3) testing the effects on processing of adding barrier materials to the LEU metal-foil target. The experimental results show that switching from dissolving the target in the sulfuric/nitric mixture to using nitric acid alone should cause no significant difference in 99Mo product yield or purity. Further, the results show that overall decontamination factors for gamma emitters in the LEU-target processing are high enough to meet the purity requirements for the 99Mo product. The results also show that the selected barrier materials, Cu, Fe, and Ni, do not interfere with 99Mo recovery and can be removed during chemical processing of the LEU target.
Book Synopsis Processing of LEU Targets For[sup 99]Mo Production--testing and Modification of the Cintichem Process by :
Download or read book Processing of LEU Targets For[sup 99]Mo Production--testing and Modification of the Cintichem Process written by and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Recent experimental results on testing and modification of the Cintichem process to allow substitution of low enriched uranium (LEU) for high enriched uranium (HEU) targets are presented in this report. The main focus is on[sup 99]Mo recovery and purification by its precipitation with[alpha]-benzoin oxime. Parameters that were studied include concentrations of nitric and sulfuric acids, partial neutralization of the acids, molybdenum and uranium concentrations, and the ratio of[alpha]-benzoin oxime to molybdenum. Decontamination factors for uranium, neptunium, and various fission products were measured. Experiments with tracer levels of irradiated LEU were conducted for testing the[sup 99]Mo recovery and purification during each step of the Cintichem process. Improving the process with additional processing steps was also attempted. The results indicate that the conversion of molybdenum chemical processing from HEU to LEU targets is possible.
Book Synopsis Full-Scale Testing of the Ambient Pressure, Acid-Dissolution Front-End Process for the Current 99Mo Recovery Processes by :
Download or read book Full-Scale Testing of the Ambient Pressure, Acid-Dissolution Front-End Process for the Current 99Mo Recovery Processes written by and published by . This book was released on 2013 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Global Threat Reduction Initiative (GTRI) Conversion Program is actively developing technologies for converting civilian facilities that use high enriched uranium (HEU) to low enriched uranium (LEU) fuels and targets. The conversion of conventional HEU targets to LEU for the production of 99Mo production requires approximately five times the uranium in a target to maintain the 99Mo yield on a per-target basis. Under GTRI, Argonne National Laboratory (Argonne) is developing two frontend options for current 99Mo production processes to allow the use of LEU-foil targets. In both processes, the aim is to produce a frontend product that is compatible with current 99Mo purification operations and will provide the same or a higher yield of 99Mo for the same number of irradiated targets. The two frontend processes under development as part of this project are (1) the dissolution of irradiated LEU foil (up to 250 g in a single batch) and nickel fission recoil barrier in nitric acid at ambient pressure; and (2) the electrochemical dissolution of LEU foil in series of steps that produces an alkaline (basic) solution feed for 99Mo purification. This report describes results from performance tests and design optimization of the ambient pressure, nitric-acid-dissolver system. The design, fabrication, and performance test planning for this system are described in more detail in previous reports (Jerden et al. 2011a, b, 2012). Full-scale demonstrations of both of the frontend processes using irradiated uranium foils are planned to be performed at Oak Ridge National Laboratory this fiscal year.
Book Synopsis Processing of LEU Targets for 99Mo Production -- Demonstration of a Modified Cintichem Process by :
Download or read book Processing of LEU Targets for 99Mo Production -- Demonstration of a Modified Cintichem Process written by and published by . This book was released on 1995 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt: Two demonstrations of the use of the Cintichem process on simulated low enriched uranium (LEU,
Book Synopsis Processing of LEU Targets For[sup 99]Mo Production -- Demonstration of a Modified Cintichem Process by :
Download or read book Processing of LEU Targets For[sup 99]Mo Production -- Demonstration of a Modified Cintichem Process written by and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Two demonstrations of the use of the Cintichem process on simulated low enriched uranium (LEU,
Book Synopsis Progress in Dissolving Modified LEU Cintichem Targets by :
Download or read book Progress in Dissolving Modified LEU Cintichem Targets written by and published by . This book was released on 1996 with total page 31 pages. Available in PDF, EPUB and Kindle. Book excerpt: A process is under development to use low-enriched uranium (LEU) metal targets for production of 99Mo. The first step is to dissolve the irradiated foil. In past work, this has been done by heating a closed (sealed) vessel containing the foil and a solution of nitric and sulfuric acids. In this work, the authors have demonstrated that (1) the dissolver solution can contain nitric acid alone, (2) uranium dioxide is also dissolved by nitric acid alone, and (3) barrier metals of Cu, Fe, or Ni on the U foil are also dissolved by nitric acid. Changes to the dissolver design and operation needed to accommodate the uranium foil are discussed, including (1) simple operations that are easy to do in a remote-maintenance facility, (2) heat removal from the irradiated LEU foil, and (3) cold trap operation with high dissolver pressures.
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