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Uranium Peroxide

Description: It was desired to investigate the precipitation of UO{sub 4} in acid solution, in order to determine the suitability of this reaction for use in the purification of uranium. A series of tests was performed to establish the conditions for precipitation of UO{sub 4}. It was found that uranium could be completely precipitated from pure uranyl sulfate solution at a pH of 2.5 to 3.5, with only silght excess of H{sub 2}O{sub 2}. The presence of sodium sulfate interferred with complete precipitation. It was established that vanadium was preferentially oxidized, when present.
Date: April 14, 1947
Creator: Brimm, E. O., Dr. & Nohr, P.
Partner: UNT Libraries Government Documents Department

Precipitation of Sodium Diuranate from Pitchblende Liquors

Description: In the treatment of carnotite concentrates, sodium diuranate was prepared by acidifying tricarbonate liquors to eliminate carbon dioxide, and then precipitating the sodium salt by the addition of caustic. Direct precipitation of uranium by the addition of caustic to tricarbonate liquors was used when pitchblende ores were processed, because this procedure was more effective in giving a product with a low molybdenum content. Tests of this method in the laboratory and Pilot Plant indicated that low uranium losses (0.2 to 0.3%) would be encountered with typical liquors if 1.7 to 2.0 lbs of caustic were added for every pound of uranosic oxide in solution. Since losses as high as 3% were incurred in plant operations, further work was undertaken, in an effort to reduce the uranium concentration in the waste liquors.
Date: February 4, 1947
Creator: Brimm, E. O., Dr.
Partner: UNT Libraries Government Documents Department

The Precipitation of Uranium Peroxide in the Presence of Fluorides

Description: The large-scale recovery of uranium from materials which also contained great quantities of fluorides did not give a product which had a low enough fluoride content to be treated satisfactorily by the other extraction process. The objective of the investigations carried out in this laboratory was a method of reducing the amount of fluoride which accompanied the uranium. The material from which the uranium was recovered in the industrial process was a slag containing (in addition to uranium) magnesium fluoride, calcium and dolomitic lines, crucible dross, and other waste products from the reaction of magnesium metal and uranium hexafluoride. Most of the fluoride was removed from this mixture by heating the roasted and ground slag with sulfuric acid. The residue was mixed with water and much of the caclium sulfate and fluoride, magnesium fluoride, and hydrated ferric oxide and alumina was precipitated by reducing the acidity. After filtering off the precipitate, ammonium sulfate was added to the solution and uranium peroxide (UO{sub 4} {center_dot} 2H{sub 2}O) was precipitated by addition of hydrogen peroxide. The pH of the solution was maintained between 3.0 and 3.5 during the precipitation by addition of sodium hydroxide. The uranium peroxide, even after washing, contained between 2 and 3% fluoride. The percentage of fluoride could be reduced to 0.5% by precipitating the peroxide from a more acidic solution but this required the use of much larger amounts of hydrogen peroxide.
Date: January 1, 1941
Creator: King, Edward J.
Partner: UNT Libraries Government Documents Department

Preparation and use of Ammonium Diuranate in the Ether Extraction Process

Description: In the ether extraction process, as originally developed, purified uranium dioxide was obtained by evaporation and calcination of the uranyl nitrate solution, followed by calcination of the resultant UO{sub 3}. It was suggested that an alternate procedure might be developed, involving the precipitation of uranium from the nitrate solution as ammonium diuranate. This material could then be calcined to uranosic acid, or reduced directly to the dioxide. It had already been established that ammonium diuranate could be precipitated completely from uranyl nitrate solutions. Experiments were carried out to determine whether a basic nitrate, analogous to a known sulfate salt, would be formed in the process. Both direct reduction of the diuranate to UO{sub 2} and calcination to uranosic acid were investigated to determine the physical characteristics and residual nitrogen of the resultant brown oxide.
Date: February 4, 1947
Creator: Brimm, E. O., Dr. & Mohr, P.
Partner: UNT Libraries Government Documents Department

Winter storms and the Spring Transition over the western U.S.: Quantifying discrepancies between coarse and high-resolution simulations and observations

Description: This project addressed the ability of the Community Climate System Model (CCSM3 and CCSM4), the Community Earth System Model (CESM), and other models to simulate the processes involved in controlling winter storms affecting the U.S. West Coast as well as other precipitation processes in the climate system.
Date: November 14, 2012
Creator: Miller, Arthur; Cayan, Daniel & Pierce, David
Partner: UNT Libraries Government Documents Department

Diffusional creep of multicomponent systems. Progress report, February 1, 1975--January 31, 1976

Description: Hydrogen embrittlement was studied from the viewpoint of the interaction of hydrogen with the stress field of particles. The interaction between dislocation loops was studied to include shear components of the Burgers vector. It turned out that this additional component could stabilize both the cuboidal arrangement and the stair-step configuration of square dislocation loops. These results were used to explain certain precipitation morphologies. Equipment improvements are reported. The only creep results obtained so far were the temperature and stress dependences of penetration velocity on a beta-tin single crystal, and the stress dependences of lead and succinonitrile polycrystals. They agree with literature data. (DLC)
Date: January 1, 1976
Creator: Li, J.C.M.
Partner: UNT Libraries Government Documents Department


Description: Three methods for the determination of radium were evaluated. In two methods, the radium is finally precipitated with barium sulfate as carrier and alpha-counted. In the other method, the radium is recovered in a carrierfree condition for alpha counting. A method for determining radium by removing interfering elements with solvent extraction technniques and precipitating the radium with barium sulfate is described. A method which gives a rapid estimation of radium isotopic composition in samples, based on precipitation with barium sulfate, conversion to the carbonate, and alpha counting, is described. Flowsheets are contained on all five processes discussed. Two processes for the determination of thorium were evaluated. One method consists essentially of extraction of carrierfree thorium in TTA-benzene, stripped in nitric acid, and direct plating of the nitric acid solution for counting. The second method consists of thorium precipitation on lanthanum hydroxide, then on lanthanum fluoride, dissolution in nitric acid aluminum nitrate, thorium extraction into TTA solution, stripping into nitric acid, and counting. Flowsheets for the processes are given. The effects of pH, sulfate ion concentration, calcium and other contaminants, and temperature on the adsorption of radium from acid leach liquors by barite were studied. Coprecipitation studies of radium with barium sulfate from mill effluent streams were investigated. (For preceding period see WlN-115.) (C.J.G.)
Date: October 31, 1960
Creator: Herrington, A.C. comp. and ed.
Partner: UNT Libraries Government Documents Department


Description: LAMPRE-L The reactor was started up and held st 160 deg C and at hot critical for various measurements. Some of the 160 deg C measurements included rod worth, temperature coefficient, and shim-down extrapolated mass. In the approach to hot critical, multiplication was measured during the temperature increase from 160 to 500 deg C and found to increase markedly when the core meltsd. Reactivity changes due to jarring of the fuel capsules to remove bubbles and voids in the melted fuel were observed. Zero measurements made at 48O deg C are reported. Power coefficient measurements at 0 to 46 kw and power demand experiments were made, and the 50-kw transfer function is plotted. Shielding inadequacies are discussed briefly. The results of a fuel pin scan are given. Observations on the performance of the sodium system are discuaaed. Type 17-4 PH stainless steel was found to undergo additional grain boundary precipitution during long-term exposure to temperatures below the hardening temperature, and measurements of its properties are reported. fuel and Container Development. Impurities in the LAaMPRE-1 fuel which has a corrosive effect on the fuel container are discussed. Observations in the Pu -Ce-Co phase diagram are reported. Different types of LAMPRE-1 capsule failure are discussed. Work on improving the corrosion resiatance of Ta revealed Y and W to be beneficial additives. Sodium Test Facility. The test facility was opersted nearly continuously. with test equipment pieces receiving total operating times as high as 10,400 hr. The He cover gas in the primary and secondary loops was analyzed for buildup of O/sub 2/, H/sub 2/, and CH/sub 4/. (D.L.C.)
Date: June 1, 1961
Partner: UNT Libraries Government Documents Department


Description: 8 7 < 6 ; : : = 8 g developed for recovering fissionable and fertile materials from shortcooled reactor fuels. The second laboratory demonstration of the melt-refining process with highly irradiated EBR- IItype fuel pins was completed. A 392-g charge of U-5% fissium fuel pins irradiated to an estimated burnup of 0.4 total at.% and cooled 28 days was melt refined for three hours at 1400 deg C. Data were not obtained on the behavior of fission products. The effect of N concentration on the nitridation rates of unirradiated U-fissium alloys in Ar-N atmospheres was determined. Experiments on the storage of fuel pins at 350 deg C in Ar atmospheres showed that the presence of 5% N lowered product yields only slightly during subsequent melt-refining operations. Supplementary pouring techniques, such as the use of probes and mashers designed to break crusts over the melts, are moderately effective, but are a less desirable solution to the problem of maintaining high yields than the elimination of contaminants in the Ar atmosphere. A liquid metal process is under development for recovery of the fissionable material contained in melt refining crucible skulls produced in the EBR-II fuel cycle. Information obtained in separate studies of the individual process steps is listed. A systematic study is underway to ascertain the influence of atomic size, metallic valence, and electronic configuration on the coprecipitation of various metallic elements with the Cd-Ce intermetallic phase CeCd/sub 11/. Values for the coprecipitation coefficient lambda , defined by the equation log (tracer in solution/ total tracer) = lambda log (carrier in solution/total carrier), were determined for Na, Li, K, Y, Ba, lambda = 0; La, lambda = 1.49; Th, lambda = 1.08; Pr, lambda = 0.63; Ga, lambda = 0.23; Sm, lambda = 0.17; U, lambda = 0.13; Sr, lambda = ...
Date: October 31, 1961
Partner: UNT Libraries Government Documents Department

DEVELOPMENT OF PLUTONIUM-BEARING FUEL MATERIALS. Progress Report, January 1 through March 31, 1963

Description: Three batches of PuO/sub 2/ were prepared via the plutonium peroxide route. Except for the high tap density, it was found that the powder characteristics of PuO/sub 2/ prepared in this manner are similar to the characteristics of PuO/sub 2/ prepared by the oxalate route. Modifications were made to equipment for preparation of mixed oxides to achieve better reproducibility and minimize operator time. A study was initiated to assess the feasibility of using gamma spectrometry for rapid in-process determination of plutonium in solutions that also contain uranium. It was found that plutonium can be determined to within 1% Provided that the uranium concentration is known to better than 2 mg/ml. Plutonium separation studies using TTA extraction were continued and the determination of cesium and strontium fission products by flame photometry was investigated. The effect of carbon content on the weight loss of PuO/sub 2/ during sintering was determined. Metallographic examination of sintered UO/sub 2/--35 wt% PuO/sub 2/ pellets indicated that the low densities obtained may be due to grain growth and broadening of grain boundaries. Green spheres of PuO/sub 2/ were formed in a small mill jar and the particle size distributions of both the formable and non-formable powder fractions were determined by centrifugal sedimentation size analysis. Preparation of duplex pellets for determining the reaction between PuO/sub 2/-- UO/sub 2/ and possible cladding and diluent metals was continued. Pellets of pure PuO/sub 2/ and six compositions of coprecipitated PuO/sub 2/-- UO/sub 2/ were fabricated for corrosion testing in water and steam. Preliminary tests in steam at 750 deg F and 2200 psi for 10 hr showed no visual evidence of corrosion. The NUSURP code was modified to allow calculation of undermoderated systems. Equipment is being installed in alpha boxes. (M.C.G.)
Date: October 31, 1964
Partner: UNT Libraries Government Documents Department


Description: No Description Available.
Date: October 1970
Partner: UNT Libraries Government Documents Department


Description: In order to meet contract requirements on the concentrations of strontium-90 and transuranic isotopes in the immobilized low-activity waste, strontium-90 and transuranics must be removed from the supernate of tanks 241-AN-102 and 241-AN-107. The process currently proposed for this application is an in-tank precipitation process using strontium nitrate and sodium permanganate. Development work on the process has not proceeded since 2005. The purpose of the evaluation is to identify whether any promising alternative processes have been developed since this issue was last examined, evaluate the alternatives and the baseline process, and recommend which process should be carried forward.
Date: April 25, 2011
Creator: CS, SMALLEY
Partner: UNT Libraries Government Documents Department

Modeling brine-rock interactions in an enhanced geothermal systemdeep fractured reservoir at Soultz-Sous-Forets (France): a joint approachusing two geochemical codes: frachem and toughreact

Description: The modeling of coupled thermal, hydrological, and chemical (THC) processes in geothermal systems is complicated by reservoir conditions such as high temperatures, elevated pressures and sometimes the high salinity of the formation fluid. Coupled THC models have been developed and applied to the study of enhanced geothermal systems (EGS) to forecast the long-term evolution of reservoir properties and to determine how fluid circulation within a fractured reservoir can modify its rock properties. In this study, two simulators, FRACHEM and TOUGHREACT, specifically developed to investigate EGS, were applied to model the same geothermal reservoir and to forecast reservoir evolution using their respective thermodynamic and kinetic input data. First, we report the specifics of each of these two codes regarding the calculation of activity coefficients, equilibrium constants and mineral reaction rates. Comparisons of simulation results are then made for a Soultz-type geothermal fluid (ionic strength {approx}1.8 molal), with a recent (unreleased) version of TOUGHREACT using either an extended Debye-Hueckel or Pitzer model for calculating activity coefficients, and FRACHEM using the Pitzer model as well. Despite somewhat different calculation approaches and methodologies, we observe a reasonably good agreement for most of the investigated factors. Differences in the calculation schemes typically produce less difference in model outputs than differences in input thermodynamic and kinetic data, with model results being particularly sensitive to differences in ion-interaction parameters for activity coefficient models. Differences in input thermodynamic equilibrium constants, activity coefficients, and kinetics data yield differences in calculated pH and in predicted mineral precipitation behavior and reservoir-porosity evolution. When numerically cooling a Soultz-type geothermal fluid from 200 C (initially equilibrated with calcite at pH 4.9) to 20 C and suppressing mineral precipitation, pH values calculated with FRACHEM and TOUGHREACT/Debye-Hueckel decrease by up to half a pH unit, whereas pH values calculated with TOUGHREACT/Pitzer increase by a similar ...
Date: December 31, 2006
Creator: Andre, Laurent; Spycher, Nicolas; Xu, Tianfu; Vuataz,Francois-D. & Pruess, Karsten.
Partner: UNT Libraries Government Documents Department

The Effect of Organic Ligands on the Sorption of Neodymium, Gadolinium and Uranium onto Nontronite and Goethite

Description: The sorption of the rare earth elements (REE) Nd(III) and Gd(III) onto goethite in the presence of Suwannee River fulvic acid in 0.1 m NaCl solutions at 25 ÂșC was investigated quantitatively. The experiments involved batch titrations whereby the concentrations of REE and/or fulvic acid remaining in solution were determined as a function of pH. In the absence of fulvic acid, removal of REE from solution is enhanced in the presence of goethite over the pH range from 6 to 8, compared to the unary system (REE only) in which precipitation of an amorphous hydroxide occurred at pH greater than or equal to 8. In the absence of REE, removal of fulvic acid from solution is enhanced in the presence of goethite in the pH range from 2 to 8 at least 9, compared to a unary (fulvic acid only) system. The presence of fulvic acid at concentrations from 10 to 50 ppm enhanced REE sorption onto goethite slightly at pH less than 7, but had no discernable effect at higher pH values. Fulvic acid at a concentration of 100 ppm exhibited a greater enhancement of REE sorption at pH < 7, but inhibited REE sorption slightly at pH > 7. Experiments investigating the effect of sorption of REE onto goethite by citrate were also performed. However, these studies were not completed owing to experimental difficulties. The results obtained in this study represent an important contribution to the ultimate goal of predicting the mobility of trivalent REE (and analogous trivalent actinides) in the presence of natural organic matter and goethite.
Date: June 12, 2007
Creator: Wood, Scott A.
Partner: UNT Libraries Government Documents Department

Nevada Test Site 2005 Waste Management Monitoring Report Area 3 and Area 5 Radioactive Waste Management Sites

Description: Environmental monitoring data were collected at and around the Area 3 and Area 5 Radioactive Waste Management Sites (RWMSs) at the Nevada Test Site. These data are associated with radiation exposure, air, groundwater, meteorology, vadose zone, subsidence, and biota. This report summarizes the 2005 environmental data to provide an overall evaluation of RWMS performance and to support environmental compliance and performance assessment activities. Some of these data (e.g., radiation exposure, air, and groundwater) are presented in other reports (U.S. Department of Energy, 2005; Grossman, 2005; Bechtel Nevada, 2006). Direct radiation monitoring data indicate that exposure levels around the RWMSs are at or below background levels. Air monitoring data at the Area 3 and Area 5 RWMSs indicate that tritium concentrations are slightly above background levels. There is no detectable man-made radioactivity by gamma spectroscopy, and concentrations of americium and plutonium are only slightly above detection limits at the Area 3 RWMS. Measurements at the Area 5 RWMS show that radon flux from waste covers is no higher than natural radon flux from undisturbed soil in Area 5. Groundwater monitoring data indicate that the groundwater in the uppermost aquifer beneath the Area 5 RWMS is not impacted by facility operations. Precipitation during 2005 totaled 219.1 millimeters (mm) (8.63 inches [in.]) at the Area 3 RWMS and 201.4 mm (7.93 in.) at the Area 5 RWMS. Soil-gas tritium monitoring continues to show slow subsurface migration consistent with previous results. Moisture from precipitation at Area 5 has percolated to the bottom of the bare-soil weighing lysimeter, but this same moisture has been removed from the vegetated weighing lysimeter by evapotranspiration. Vadose zone data from the operational waste pit covers show that precipitation from the fall of 2004 and the spring of 2005 infiltrated past the deepest sensors at 188 centimeters (6.2 feet) and ...
Date: August 1, 2006
Creator: David B. Hudson, Cathy A. Wills
Partner: UNT Libraries Government Documents Department

Public Health-Related Impacts of Climate Change inCalifornia

Description: In June 2005 Governor Arnold Schwarzenegger issued Executive Order S-3-05 that set greenhouse gas emission reduction targets for California, and directed the Secretary of the California Environmental Protection Agency to report to the governor and the State legislature by January 2006 and biannually thereafter on the impacts to California of global warming, including impacts to water supply, public health, agriculture, the coastline, and forestry, and to prepare and report on mitigation and adaptation plans to combat these impacts. This report is a part of the report to the governor and legislature, and focuses on public health impacts that have been associated with climate change. Considerable evidence suggests that average ambient temperature is increasing worldwide, that temperatures will continue to increase into the future, and that global warming will result in changes to many aspects of climate, including temperature, humidity, and precipitation (McMichael and Githeko, 2001). It is expected that California will experience changes in both temperature and precipitation under current trends. Many of the changes in climate projected for California could have ramifications for public health (McMichael and Githeko, 2001), and this document summarizes the impacts judged most likely to occur in California, based on a review of available peer-reviewed scientific literature and new modeling and statistical analyses. The impacts identified as most significant to public health in California include mortality and morbidity related to temperature, air pollution, vector and water-borne diseases, and wildfires. There is considerable complexity underlying the health of a population with many contributing factors including biological, ecological, social, political, and geographical. In addition, the relationship between climate change and changes in public health is difficult to predict for the most part, although more detailed information is available on temperature-related mortality and air pollution effects than the other endpoints discussed in this document. Consequently, these two topics ...
Date: December 1, 2005
Creator: Drechsler, D.M.; Motallebi, N.; Kleeman, M.; Cayan, D.; Hayhoe,K.; Kalkstein, L.S. et al.
Partner: UNT Libraries Government Documents Department

Overcoming Constraints to High-Yield Plantation-Grown Hardwoods in the Southeastern United States

Description: This project was comprised of the following four inter-related tasks: Task 1 Plantation Maintenance and Measurement--Data on dry weight productivity per tree and/or growth as measured by individual tree height and diameter at a specified height on the stem was determined at the end of each of five years corresponding to ages 2 through 6. Measurements of height and diameter were recorded once a month during the growing season on a subsample of four trees per clone per species per treatment combination. Dry biomass in the leaf litter traps during the growing season once the canopy has closed was periodically collected and measured. Foliar nutrient levels were determined once a month by removing LPI 8 on each subsampled measurement tree and completing nutrient analyses. Weather data, including precipitation, minimum and maximum temperature and photosynthetically active radiation on an hourly basis were recorded daily. Information on irrigation rates and fertilization levels were collected. Task 2 Intra- And Interspecific Variation In Osmotic Potential--The specific objectives of this task were: (1) to determine whether limitation in water availability constrains productivity and influences leaf osmotic potential of cottonwood, sycamore, and/or sweetgum growing under short-rotation field conditions, (2) to document the occurrence of osmotic adjustment under varying levels of water availability levels, and (3) to determine the effect of nitrogen fertilization on osmotic potential and response to irrigation. Task 3 Leaf Gas Exchange And Water-Use Efficiency--The specific objectives of this task were: (1) to quantify the contribution of photosynthesis, respiration, and water-use efficiency to the productivity of individual cottonwood, sycamore, and sweetgum trees grown under various levels of water and/or nutrient availability, and (2) to quantify intra- and interspecific variability for photosynthesis, respiration, and water-use efficiency for cottonwood, sycamore, and/or sweetgum. Task 4 Whole-Plant Carbon Budgets--The specific objectives of this task were: (1) to evaluate ...
Date: June 26, 2008
Partner: UNT Libraries Government Documents Department