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Optimising The Dissolution Of U Al In Alkaline Solutions And Subsequent Dissolution Of The Generated Uranium Residue In Nitric Acid
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Book Synopsis Optimising the Dissolution of U/Al in Alkaline Solutions and Subsequent Dissolution of the Generated Uranium Residue in Nitric Acid by :
Download or read book Optimising the Dissolution of U/Al in Alkaline Solutions and Subsequent Dissolution of the Generated Uranium Residue in Nitric Acid written by and published by . This book was released on 2019 with total page 148 pages. Available in PDF, EPUB and Kindle. Book excerpt: Aluminium -- Dissolution -- Uranium.
Book Synopsis Nitric Acid Dissolution of Uranium-aluminum Alloy by : R. E. Burns
Download or read book Nitric Acid Dissolution of Uranium-aluminum Alloy written by R. E. Burns and published by . This book was released on 1952 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Analysis of UO2 Dissolution in Nitric Acid Solution by : H. F. Johnson
Download or read book Analysis of UO2 Dissolution in Nitric Acid Solution written by H. F. Johnson and published by . This book was released on 1962 with total page 42 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis The Nitric Acid Dissolution of Uranium-Aluminum Alloy in a Flooded Continuous Dissolver by :
Download or read book The Nitric Acid Dissolution of Uranium-Aluminum Alloy in a Flooded Continuous Dissolver written by and published by . This book was released on 1954 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Extensive pilot plant studies of the mercury-catalyzed nitric acid dissolution of unirradiated 7.5% uranium--92.5% aluminum alloy slugs were carried out in tall-pipe, flooded, continuous dissolvers, In producing an acidic product containing 1.2M aluminum nitrate, dissolution rates as high as 15 kg of aluminum per day per square inch of cross section were achieved. Countercurrent flow of metal and acid has some advantages over concurrent flow, The large heat of reaction produced great volumes of steam in the dissolvers; the operational problems due to the resulting foam were best solved by the use of an over head reflux condenser to condense, partially or totally, the steam in the off-gas. Only minor quantities of solids were found in acidic product solutions. Extruded alloy dissolved abcut twice as fast as cast alloy, The metal dissolving rate was directly proportional to the 0.8 power of the nitric acid feed rate and tc the cube root of the mercuric ion (catalyst) concentration. The maximim dissolving rates occurred at feed acid concentrations of abcut 3M for cast slugs and 5M for extruded alloy, The system studied is inherently self-regulating in that a uniform product composition will normally be produced by feeding slugs, nitric acid, and catalyst at constant rates. The occasional minor rate adjustments are best accomplished by varying the catalyst concentration. Data and correlations developed are given. (auth).
Book Synopsis Preparation of Uranium (IV) Nitrate Solutions by : Robert S. Ondrejcin
Download or read book Preparation of Uranium (IV) Nitrate Solutions written by Robert S. Ondrejcin and published by . This book was released on 1961 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis The Acid Dissolution of Some Uranium Ore Concentrates: Final Report on Supporting Experimental Work for the Dow Nuclear Material Plans Studies by : H.A. Ohlgren, Lee Chajson, K.S. Sanvordenker
Download or read book The Acid Dissolution of Some Uranium Ore Concentrates: Final Report on Supporting Experimental Work for the Dow Nuclear Material Plans Studies written by H.A. Ohlgren, Lee Chajson, K.S. Sanvordenker and published by . This book was released on 1956 with total page 17 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Dissolver for Natural Uranium Fuel Elements by : Vincent P. Caracciolo
Download or read book Dissolver for Natural Uranium Fuel Elements written by Vincent P. Caracciolo and published by . This book was released on 1958 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Dissolution of Uranium Dioxide Microspheres in Carbonate and Hydrogen Peroxide Solutions by : Timothy G. Adams
Download or read book Dissolution of Uranium Dioxide Microspheres in Carbonate and Hydrogen Peroxide Solutions written by Timothy G. Adams and published by . This book was released on 2013 with total page 77 pages. Available in PDF, EPUB and Kindle. Book excerpt: Uranium dioxide has been used in industry both as a fuel for power reactors and as a target for the production of radioisotopes. One of the most important radioisotopes produced using these targets is molybdenum-99 (Mo-99, 65.94hr half-life), which is the parent isotope to technetium-99m (Tc-99m, 6.01hr half-life), a radioisotope used in 70% of diagnostic medical isotope procedures performed in the United States of America. [1] [2] Molybdenum-99, produced by either the thermal neutron fission of uranium-235 in nuclear reactors or by neutron activation of molybdenum-98, is purified, packaged, and shipped to hospitals worldwide. The maximal activity of Tc-99m is reached in 22.9hrs, so it can be milked from the parent Mo-99 repeatedly. Mo-99 is one of many fission products generated during the thermal neutron fission of uranium-235. For production of Mo-99, irradiation targets based on metallic uranium, uranium alloys, or uranium dioxide are produced. After neutron irradiation in a reactor, the uranium target must first be dissolved in a suitable medium. This has traditionally been done using boiling nitric acid solutions. In literature and in industry, the use of alkaline solutions, specifically carbonate salt solutions combined with hydrogen peroxide, are being explored as an alternative to the nitric acid based dissolution process. The carbonate-peroxide dissolution scheme has several advantages over traditional nitric acid dissolutions including less damage to equipment during operation and smaller volumes of waste produced during process. This thesis research work explores the initial dissolution rates of uranium dioxide in carbonate medium containing hydrogen peroxide. Effect of three different counter cations- ammonium, sodium, and potassium - on the dissolution behavior of uranium was investigated. The kinetic factors of dissolution, activation energy, frequency factor, and reaction order with respect to both the carbonate salt and hydrogen peroxide were found for each of these systems. Information in this thesis is organized into six chapters and list of cited literature sources.
Book Synopsis Neutralizations of High Aluminum Low Uranium Used Nuclear Fuel Solutions Containing Gadolinium as a Neutron Poison by :
Download or read book Neutralizations of High Aluminum Low Uranium Used Nuclear Fuel Solutions Containing Gadolinium as a Neutron Poison written by and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: H-Canyon will begin dissolving High Aluminum - Low Uranium (High Al/Low U) Used Nuclear Fuel (UNF) following approval by DOE which is anticipated in CY2011. High Al/Low U is an aluminum/enriched uranium UNF with small quantities of uranium relative to aluminum. The maximum enrichment level expected is 93% 235U. The High Al/Low U UNF will be dissolved in H-Canyon in a nitric acid/mercury/gadolinium solution. The resulting solution will be neutralized and transferred to Tank 39H in the Tank Farm. To confirm that the solution generated could be poisoned with Gd, neutralized, and discarded to the Savannah River Site (SRS) high level waste (HLW) system without undue nuclear safety concerns the caustic precipitation of simulant solutions was examined. Experiments were performed with three simulant solutions representative of the H-Canyon estimated concentrations in the final solutions after dissolution. The maximum U, Gd, and Al concentration were selected for testing from the range of solution compositions provided. Simulants were prepared in three different nitric acid concentrations, ranging from 0.5 to 1.5 M. The simulant solutions were neutralized to four different endpoints: (1) just before a solid phase was formed (pH 3.5-4), (2) the point where a solid phase was obtained, (3) 0.8 M free hydroxide, and (4) 1.2 M free hydroxide, using 50 wt % sodium hydroxide (NaOH). The settling behavior of the neutralized solutions was found to be slower compared to previous studies, with settling continuing over a one week period. Due to the high concentration of Al in these solutions, precipitation of solids was observed immediately upon addition of NaOH. Precipitation continued as additional NaOH was added, reaching a point where the mixture becomes almost completely solid due to the large amount of precipitate. As additional NaOH was added, some of the precipitate began to redissolve, and the solutions neutralized to the final two endpoints mixed easily and had expected densities of typical neutralized waste. Based on particle size and scanning electron microscopy analyses, the neutralized solids were found to be homogeneous and less than 20 microns in size. The majority of solids were less than 4 microns in size. Compared to previous studies, a larger percentage of the Gd was found to precipitate in the partially neutralized solutions (at pH 3.5-4). In addition the Gd:U mass ratio was found to be at least 1.0 in all of the solids obtained after partial or full neutralization. The hydrogen to U (H:U) molar ratios for two accident scenarios were also determined. The first was for transient neutralization and agitator failure. Experimentally this scenario was determined by measuring the H:U ratio of the settled solids. The minimum H:U molar ratio for solids from fully neutralized solutions was 388:1. The second accident scenario is for the solids drying out in an unagitiated pump box. Experimentally, this scenario was determined by measuring the H:U molar ratio in centrifuged solids. The minimum H:U atom ratios for centrifuged precipitated solids was 250:1. It was determined previously that a 30:1 H:Pu atom ratio was sufficient for a 1:1 Gd:Pu mass ratio. Assuming a 1:1 equivalence with 239Pu, the results of these experiments show Gd is a viable poison for neutralizing U/Gd solutions with the tested compositions.
Book Synopsis Fundamental Aspects of the Dissolution of Uranium in Alkaline Carbonate Solutions. Preliminary Results, Using Witwatersrand Uraninite Powder by :
Download or read book Fundamental Aspects of the Dissolution of Uranium in Alkaline Carbonate Solutions. Preliminary Results, Using Witwatersrand Uraninite Powder written by and published by . This book was released on 1966 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The dissolution of Witwatersrand uraninite powder was investigated in alkaline carbonate-bicarbonate solutions. Preliminary data were obtained regarding the dependence of the rate of dissolution of uranium upon the reagent concentration, the temperature, the stirring speed, aeration, and substances acting as catalysts during the oxidation by oxygen of U(IV) to U(VI). The presence of copper with cyanide or ammonia or with both cyanide and ammonia, was found to accelerate the dissolution of uranium in aerated carbonate solutions. Reference is made to data in the literature concerning the composition of the leach liquor, and the results obtained are discussed with reference to this information.
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 Medical Isotope Production Without Highly Enriched Uranium by : National Research Council
Download or read book Medical Isotope Production Without Highly Enriched Uranium written by National Research Council and published by National Academies Press. This book was released on 2009-06-27 with total page 220 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is the product of a congressionally mandated study to examine the feasibility of eliminating the use of highly enriched uranium (HEU2) in reactor fuel, reactor targets, and medical isotope production facilities. The book focuses primarily on the use of HEU for the production of the medical isotope molybdenum-99 (Mo-99), whose decay product, technetium-99m3 (Tc-99m), is used in the majority of medical diagnostic imaging procedures in the United States, and secondarily on the use of HEU for research and test reactor fuel. The supply of Mo-99 in the U.S. is likely to be unreliable until newer production sources come online. The reliability of the current supply system is an important medical isotope concern; this book concludes that achieving a cost difference of less than 10 percent in facilities that will need to convert from HEU- to LEU-based Mo-99 production is much less important than is reliability of supply.
Book Synopsis Uranium Dioxide Dissolution Under Acidic Aqueous Conditions by :
Download or read book Uranium Dioxide Dissolution Under Acidic Aqueous Conditions written by and published by . This book was released on 1995 with total page 3 pages. Available in PDF, EPUB and Kindle. Book excerpt: Understanding of the long-term dissolution of waste forms in groundwater is required for the safe disposal of high level nuclear waste in a geologic repository, because waste-form radionuclides could be released by dissolution and transported in groundwater. The dissolution of the uranium dioxide (UO2) matrix in spent nuclear fuel is considered the rate-limiting step for release of radioactive fission products. The intrinsic UO2 dissolution rate sets an upper limit on the aqueous radionuclide release rate. Unsaturated spent fuel tests have shown that pH's of leachates have decreased to a range of 4 to 6, presumably due to air radiolysis that oxidizes nitrogen, producing nitric acid. Dissolution rates under such acidic conditions may be different than those previously reported for alkaline groundwater conditions. No dissolution rate measurements of UO2 or spent fuel have been reported for acidic conditions possibly relevant to a geologic repository. The purpose of our work has been to measure the intrinsic dissolution rates of uranium dioxide under acidic conditions that are relevant to a repository and allow for modeling. Experiments have been completed at room-temperature and 75 C, pH's of 4 and 6, and air and oxygen saturated aqueous solutions. These are compared with earlier work on spent fuel and UO2 using alkaline solutions.
Download or read book Solvent Extraction of Uranium written by and published by . This book was released on 1957 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Recovery of Uranium from Residues Produced in Hydrochlorination of Nuclear Fuel Alloys by :
Download or read book Recovery of Uranium from Residues Produced in Hydrochlorination of Nuclear Fuel Alloys written by and published by . This book was released on 1959 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Chlorination at 550 to 600 deg C of Zircex residues with carbon tetrachloride resulted in greater than 99.99% recovery of the uranium. Both the hydrochlorination residue and the solids which remain after leaching the hydrochlorination residue with nitric acid were chlorinated with similar results. By this technique, loss of 1 to 6% of the uranium to the nitric acid insoluble residue, which occurs in simple hydrochlorination and dissolution of STR fuel, is avoided. Other advantages include reduced corrosion and the elimination of possible explosions between U-Zr alloys and nitric acid. A modified flowsheet is proposed. (auth).
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 Actinide Separations by : James D. Navratil
Download or read book Actinide Separations written by James D. Navratil and published by . This book was released on 1980 with total page 632 pages. Available in PDF, EPUB and Kindle. Book excerpt:
