L'uranium et les armes a l'uranium appauvri

CERN Document Server

Roussel, P

2001-01-01

Selon la presse, dans la guerre des Balkans et bien plus massivement dans la guerre du Golfe, des obus anti- chars ont ete utilises, avec des "charges d'uranium appauvri". La presse a decrit deux types de ces "obus- crayons", l'un de diametre 30 mm et 300 mm de long, avec une charge de 300 g d'uranium et tire par des avions, l'autre de 120 mm de diametre avec une charge de 1 a 5 Kg d'uranium, tire par des chars et donc peu ou pas utilise au Kosovo. Les commentaires ont ete varies. On a parle d'armes atomiques, on a dit que c'etait completement inoffensif ou au contraire tres dangereux. Les elements d'information qui suivent tentent d'eclairer le probleme, car on va montrer que probleme il y a, avec des donnees incontournables. Mais faute d'une enquete approfondie et faute d'informations precises, on conclura aussi avec des questions. Il a semble utile egalement de decrire quelques-unes des realites de la radioactivite et de parler du role particulier de l'uranium 238 pour notre planete.

Hot pressing of U-UC cermets and stoichiometric uranium monocarbide; Preparation par frittage sous charge de cermets U-UC et de monocarbure stoechiometrique

Energy Technology Data Exchange (ETDEWEB)

Dubuisson, J; Houyvet, A; Le Boulbin, E; Lucas, R; Moranville, C [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1958-07-01

High density fuels, either in uranium monocarbide or in U-UC cermets have been prepared on laboratory-scale, by hot pressing of mixtures of uranium powder and graphite in suitable proportions. Uranium powder is prepared by calcium reduction of UO{sub 2} followed by an acetic leaching at low temperature. An adequate protection-treatment permits the manipulation of the powder in the open air. Uranium and Graphite powders are intimately mixed and then hot pressed in a double effect graphite die at a temperature of 900-1000 deg. C under a charge of 200 kg/cm{sup 2} during 3 hours. A special design of the die avoids the breaking of the graphite during the sintering. In this way, samples are prepared, the characteristics of which are: 1) {+-} 5 pour cent of homogeneity for a ratio height/diameter = 2. 2) almost theoretical density (98 pour cent) 3) low concentration of unreacted carbon (heat treatment of stoichiometric monocarbide can be useful for completion of reaction) 4) the micrographic examination shows: - a network of monocarbide surrounding uranium in the case of low concentration cermets (<2,5 per cent C) - two networks intimately mixed for high concentration cermets (<2,5 per cent C) - a fine grain structure for the monocarbide (10 u). 5) In every case, the X rays examinations show a fine grain structure without any orientation, and no UC{sub 2}. Some indications are given on the physical (thermal cycling, conductibility) and chemical properties (corrosion, reaction with cladding materials). (author)Fren. [French] Une methode de preparation de combustibles de haute densite, soit en monocarbure d'uranium, soit en cermets U-UC, a ete mise au point au laboratoire. Il s'agit du frittage sous charge de melanges de poudres d'uranium et de graphite en proportion convenable. La poudre d'uranium est elaboree par calciothermie de l'oxyde UO{sub 2} suivie d'un lavage acetique a basse temperature. Un traitement de protection adequat pe sa manipulation a l'air. Les poudres

Uranium absorption study pile

International Nuclear Information System (INIS)

Raievski, V.; Sautiez, B.

1959-01-01

The report describes a pile designed to measure the absorption of fuel slugs. The pile is of graphite and comprises a central section composed of uranium rods in a regular lattice. RaBe sources and BF 3 counters are situated on either side of the center. A given uranium charge is compared with a specimen charge of about 560 kg, and the difference in absorption between the two noted. The sensitivity of the equipment will detect absorption variations of about a few ppm boron (10 -6 boron per gr. of uranium) or better. (author) [fr

Proceedings of the workshop on opportunities for atomic physics using slow, highly-charged ions

International Nuclear Information System (INIS)

1987-01-01

The study of atomic physics with highly-charged ions is an area of intense activity at the present time because of a convergence of theoretical interest and advances in experimental techniques. The purpose of the Argonne ''Workshop on Opportunities for Atomic Physics Using Slow, Highly-Charged Ions'' was to bring together atomic, nuclear, and accelerator physicists in order to identify what new facilities would be most useful for the atomic physics community. The program included discussion of existing once-through machines, advanced ion sources, recoil ion techniques, ion traps, and cooler rings. One of the topics of the Workshop was to discuss possible improvement to the ANL Tandem-Linac facility (ATLAS) to enhance the capability for slowing down ions after they are stripped to a high-charge state (the Accel/Decel technique). Another topic was the opportunity for atomic physics provided by the ECR ion source which is being built for the Uranium Upgrade of ATLAS. 18 analytics were prepared for the individual papers in this volume

Obtaining of uranium tetrafluoride UF4 by electrodialysis reactive from uranium concentrates

International Nuclear Information System (INIS)

Munoz Lay, Danny Mauricio

2014-01-01

The generation of uranium fuels has always been a topic worldwide. The uranium fuel manufacturing base is made under very strict parameters of radiological and industrial safety, being a stage called 'nuclear fuel cycle'. In Chile, it is done constant research for fuels. This report focuses primarily on participating in such research; mainly in the production of uranium tetrafluoride (UF 4 ) .The tetrafluoride production is very crucial for the nuclear fuel industry. Its production varies from precipitation in stirred conditions to electrolysis in mercury. However, both processes has shortcomings either in performance and environmental pollution, which is why it is proposed a new method of production based on a friendly process to the environment and easier to operate, the reactive electrodialysis (RED). Electrodialysis is a hybrid reactive process of separation by membranes, cationic and / or anionic, namely, ionic species. In the process, ions are induced to move by an electric potential applied and separated by these membranes, a highly selective physical barrier which allows passage of ions with certain charge, and prevents the passage of oppositely charged ions. And in turn, it is reactive because it forces a chemical reaction, redox, to obtain uranium tetrafluoride (UF 4 ). The results of these experiments show that by reactive electrodialysis, NH 4 UF 5 deposits were obtained. However, calcinating the NH 4 UF 5 to 450 o C, it decomposes to obtain uranium tetrafluoride, UF 4 . The best working conditions were obtained with an electric current of 0.5 (A), 41 o C and a flow of 16 (ml / s) of the electrolyte. It was possible to obtain 5,995 (g) to 3 (h), giving a current efficiency of 71.42%. In turn, working at high temperatures and flow recirculation is possible to operate with a potential difference of 1.7 (V)

A comparison between thorium-uranium and low enrichment uranium cycles in the high temperature reactors

Energy Technology Data Exchange (ETDEWEB)

Cerles, J M

1973-03-15

In a previous report, it was shown that the Uranium cycle could be used as well with multi-hole block (GGA type) as with tubular elements. Now, in a F.S.V. geometry, a comparison is made between Thorium cycle and Uranium cycle. This comparison will be concerned with the physical properties of the materials, the needs of natural Uranium, the fissile material inventory and, at last, an attempt of economical considerations. In this report the cycle will be characterizd by the fertile material. So, we write ''Thorium cycle'' for Highly Enriched Uranium - Thorium cycle and ''Uranium cycle'' for low Enrichment Uranium cycle.

Solvent extraction of uranium from high acid leach solution

International Nuclear Information System (INIS)

Ramadevi, G.; Sreenivas, T.; Navale, A.S.; Padmanabhan, N.P.H.

2010-01-01

A significant part of the total uranium reserves all over the world is contributed by refractory uranium minerals. The refractory oxides are highly stable and inert to attack by most of the commonly used acids under normal conditions of acid strength, pressure and temperature. Quantitative dissolution of uranium from such ores containing refractory uranium minerals requires drastic operating conditions during chemical leaching like high acid strength, elevated pressures and temperatures. The leach liquors produced under these conditions normally have high free acidity, which affects the downstream operations like ion exchange and solvent extraction

Three-dimensional thermal simulations of thin solid carbon foils for charge stripping of high current uranium ion beams at a proposed new heavy-ion linac at GSI

Directory of Open Access Journals (Sweden)

N. A. Tahir

2014-04-01

Full Text Available This paper presents an extensive numerical study of heating of thin solid carbon foils by 1.4  MeV/u uranium ion beams to explore the possibility of using such a target as a charge stripper at the proposed new Gesellschaft für Schwerionenforschung high energy heavy–ion linac. These simulations have been carried out using a sophisticated 3D computer code that accounts for physical phenomena that are important in this problem. A variety of beam and target parameters have been considered. The results suggest that within the considered parameter range, the target will be severely damaged by the beam. Thus, a carbon foil stripper does not seem to be a reliable option for the future Gesellschaft für Schwerionenforschung high energy heavy–ion linac, in particular, at FAIR design beam intensities.

Competitive biosorption of thorium and uranium by Micrococcus luteus

International Nuclear Information System (INIS)

Nakajima, A.; Tsuruta, T.

2004-01-01

Eighteen species of bacteria were screened for abilities to adsorb thorium and uranium. High adsorption capacity was observed for thorium by Arthrobacter nicotianae and Micrococcus luteus, and for uranium by Arthrobacter nicotianae. The adsorption of both thorium and uranium by Micrococcus luteus cells was rapid, was affected by the solution pH, and obeyed the Langmuir adsorption isotherm for binary systems in a competitive manner taking the ionic charge of the metal ion into account. The thorium selectivity in the competitive adsorption is assumed to be caused by the faster adsorption and the slower desorption rates of thorium than those of uranium. (author)

Proceedings of the workshop on opportunities for atomic physics using slow, highly-charged ions

Energy Technology Data Exchange (ETDEWEB)

1987-01-01

The study of atomic physics with highly-charged ions is an area of intense activity at the present time because of a convergence of theoretical interest and advances in experimental techniques. The purpose of the Argonne ''Workshop on Opportunities for Atomic Physics Using Slow, Highly-Charged Ions'' was to bring together atomic, nuclear, and accelerator physicists in order to identify what new facilities would be most useful for the atomic physics community. The program included discussion of existing once-through machines, advanced ion sources, recoil ion techniques, ion traps, and cooler rings. One of the topics of the Workshop was to discuss possible improvement to the ANL Tandem-Linac facility (ATLAS) to enhance the capability for slowing down ions after they are stripped to a high-charge state (the Accel/Decel technique). Another topic was the opportunity for atomic physics provided by the ECR ion source which is being built for the Uranium Upgrade of ATLAS. 18 analytics were prepared for the individual papers in this volume.

77 FR 51579 - Application for a License To Export High-Enriched Uranium

Science.gov (United States)

2012-08-24

... NUCLEAR REGULATORY COMMISSION Application for a License To Export High-Enriched Uranium Pursuant.... Complex, July 30, 2012, August Uranium (93.35%). uranium-235 high-enriched 1, 2012, XSNM3726, 11006037. contained in 7.5 uranium in the kilograms uranium. form of broken metal to the Atomic Energy of Canada...

Criticality of mixtures of plutonium and high enriched uranium

International Nuclear Information System (INIS)

Grolleau, E.; Lein, M.; Leka, G.; Maidou, B.; Klenov, P.

2003-01-01

This paper presents a criticality evaluation of moderated homogeneous plutonium-uranium mixtures. The fissile media studied are homogeneous mixtures of plutonium and high enriched uranium in two chemical forms: aqueous mixtures of metal and mixtures of nitrate solutions. The enrichment of uranium considered are 93.2wt.% 235 U and 100wt.% 235 U. The 240 Pu content in plutonium varies from 0wt.% 240 Pu to 12wt.% 240 Pu. The critical parameters (radii and masses of a 20 cm water reflected sphere) are calculated with the French criticality safety package CRISTAL V0. The comparison of the calculated critical parameters as a function of the moderator-to-fuel atomic ratio shows significant ranges in which high enriched uranium systems, as well as plutonium-uranium mixtures, are more reactive than plutonium systems. (author)

High-temperature thermal conductivity of uranium chromite and uranium niobate

International Nuclear Information System (INIS)

Fedoseev, D.V.; Varshavskaya, I.G.; Lavrent'ev, A.V.; Oziraner, S.N.; Kuznetsova, D.G.

1979-01-01

The technique of determining thermal conductivity coefficient of uranium niobate and uranium chromite on heating with laser radiation is described. Determined is the coefficient of free-convective heat transfer (with provision for a conduction component) by means of a standard specimen. The thermal conductivity coefficients of uranium chromite and niobate were measured in the 1300-1700 K temperature range. The results are presented in a diagram form. It has been calculated, that the thermal conductivity coefficient for uranium niobate specimens is greater in comparison with uranium chromite specimens. The thermal conductivity coefficients of the materials mentioned depend on temperature very slightly. Thermal conductivity of the materials considerably depends on their porosity. The specimens under investigation were fabricated by the pressing method and had the following porosity: uranium chromite - 30 %, uranium niobate - 10 %. Calculation results show, that thermal conductivity of dense uranium chromite is higher than thermal conductivity of dense uranium niobate. The experimental error equals approximately 20 %, that is mainly due to the error of measuring the temperature equal to +-25 deg, with a micropyrometer

Ionization and Coulomb explosion of small uranium oxide clusters

International Nuclear Information System (INIS)

Ross, Matt W; Castleman, A W Jr

2012-01-01

Femtosecond pulses are used to study the strong-field ionization and subsequent Coulomb explosion of small uranium oxide clusters. The resulting high atomic charge states are explored as a function of laser intensity and compared to ionization rates calculated using semi-classical tunneling theory with sequential ionization potential values. The gap in laser intensity between saturation intensity values for the 7s, 6d, and 5f orbitals are identified and quantified. Extreme charge states of oxygen up to O 4+ are observed indicating multiple ionization enhancement processes occurring within the clusters. The peak splittings of the atomic charge states are explored and compared to previous results on transition metal oxide species. Participation of the 5f orbitals in bonding is clearly identified based on the saturation intensity dependence of oxygen to uranium metal.

Uranium development in Nigeria

International Nuclear Information System (INIS)

Karniliyus, J.; Egieya, J.

2014-01-01

Nigeria uranium exploration started in 1973. Uranium was found in seven states of the country; Cross River, Adamawa, Taraba, Plateau, Bauchi, Kogi and Kano. Three government agencies were involved. At the end of the various exploration campaigns in 2001, the uranium reserve was estimated at about 200 t U. The Grade ranges from 0.63% - 0-9% at a vertical depth between 130 – 200 m. Currently, the Nigeria Atomic Energy Commission activated in 2006 is charged with the responsibility among others to prospect for and mine radioactive minerals. The main aim of this poster presentation is to review the development of uranium in Nigeria with a view to encourage local and international investors to develop and exploit these deposits. Nigeria is located on latitude 100 N and longitude 80 E surrounded in the north by Niger and Chad, in the east by Cameroun and in the west by the Benin Republic. Available data indicated the viability of mineral investment in the Nigerian uranium resources. With the current economic reforms and investment incentives in Nigeria, interested investors are highly welcome to take advantage of developing these mineral resources. (author)

Uranium sorption on tezontle volcanic rock

International Nuclear Information System (INIS)

Lopez M, B. E.; Duran B, J. M.; Iturbe G, J. L.; Olguin G, M. T.

2009-01-01

It is described a study that demonstrates that hexavalent uranium ions were sorbed by the naturally occurring mineral using a batch technique. This mineral is found in abundant quantities in Mexico. Our study focused on the separation of U Vi from synthetic aqueous systems of both H 2 O-UO 2 (NO 3 ) 2 .6H 2 O (acid) and H 2 O-Na 4 [UO 2 (CO 3 ) 3 ] (basic). The chemical speciation was performed by using high voltage electrophoresis, and the uranium content was determined by UV-Vis spectroscopy. The quantified U(Vi) sorption by tezontle from acidic and basic systems was 2.72 and 1.68 μmol/g, respectively, and the sorption behavior is discussed considering the surface charge of the tezontle at different ph values based on the point of zero charge characteristic of this material. (Author)

Neutron activation analysis of high pure uranium using preconcentration

International Nuclear Information System (INIS)

Sadikov, I.I.; Rakhimov, A.V.; Salimov, M.I.; Zinov'ev, V.G.

2006-01-01

Full text: Uranium and its compounds are used as nuclear fuel, and requirements for purity of initial uranium are very high. Therefore highly sensitive and multielemental analysis of uranium is required. One of such methods is neutron activation analysis (NAA). During irradiation of uranium by nuclear reactor neutrons the induced radioactivity of a sample is formed by uranium radionuclide 239 U (T 1/2 = 23,4 min.) and its daughter radionuclide 239 Np (T 1/2 = 2,39 d). Short-lived 239 U almost completely decays in 24 hours after irradiation and the radioactivity of the sample is mainly due to 239 Np and is more than 10 9 Bq for 0.1 g of uranium sample (F = 1*10 14 cm -2 s -1 , t irr . = 5 h). That is why nondestructive determination of the impurities is impossible and they should be separated from 239 Np. When irradiated uranium yields fission products - radionuclides of some elements with mass numbers 91-104 and 131-144. The main problem in NAA of uranium is to take into account correctly the influence of fission products on the analysis results. We have developed a radiochemical separation procedure for RNAA of uranium [1]. Comparing the results of analysis carried out by radiochemical NAA and instrumental NAA with preconcentration of trace elements can be used for evaluating the interference of fission products on uranium analysis results. Preconcentration of trace elements have been carried out by extraction chromatography in 'TBP - 6M HNO 3 ' system [1]. Experiments have shown that if 0.1 g uranium sample is taken for analysis (F = 1*10 14 cm -2 s -1 , t irr . =5 h) the apparent concentration of Y, Zr, Mo, Cs, La, Ce, Pr, Nd exceeds the true concentration by 2500-3000 times and so determination of these elements is not possible by radiochemical NAA. (author)

High-uranium-loaded U3O8--Al fuel element development program

International Nuclear Information System (INIS)

Martin, M.M.

1978-01-01

The High-Uranium-Loaded U 3 O 8 --Al Fuel Development Program supports Argonne National Laboratory efforts to develop high-uranium-density research and test reactor fuel to accommodate use of low-uranium enrichment. The goal is to fuel most research and test reactors with uranium of less than 20% enrichment for the purpose of lowering the potential for diversion of highly-enriched material for nonpeaceful usages

Prospects for future uranium savings through LWRs with high performance cores

International Nuclear Information System (INIS)

Mochida, T.; Yamamoto, T.; Sasaki, M.; Matsuura, H.; Ueji, M.; Murata, T.; Kanda, K.; Oka, Y.; Kondo, S.

1995-01-01

Since 1986, Nuclear Power Engineering Cooperation (NUPEC) has been studying four types of LWR high performance core concepts (i.e., the uranium saving core I (USC-I), the uranium saving core II (USC-II), the high moderation core (HMC) and the low moderation core (LMC)), which aim at improvement of uranium and plutonium utilization. After the evaluation of fundamental core performance and uranium and plutonium material balance for each reactor, potential uranium savings with different reactor strategies are evaluated for the Japanese scenario with assumption of the growth of future nuclear power plant generation, annual reprocessing capacity and schedules for the introduction of high performance core. At 2030, about 3-6% savings in uranium demand are expected by USC-I or USC-II strategy, while about 14% savings by HMC strategy and about 8% by LMC strategy. (author)

Transformations of highly enriched uranium into metal or oxide

International Nuclear Information System (INIS)

Nollet, P.; Sarrat, P.

1964-01-01

The enriched uranium workshops in Cadarache have a double purpose on the one hand to convert uranium hexafluoride into metal or oxide, and on the other hand to recover the uranium contained in scrap materials produced in the different metallurgical transformations. The principles that have been adopted for the design and safety of these workshops are reported. The nuclear safety is based on the geometrical limitations of the processing vessels. To establish the processes and the technology of these workshops, many studies have been made since 1960, some of which have led to original achievements. The uranium hexafluoride of high isotopic enrichment is converted either by injection of the gas into ammonia or by an original process of direct hydrogen reduction to uranium tetrafluoride. The uranium contained m uranium-zirconium metal scrap can be recovered by combustion with hydrogen chloride followed treatment of the uranium chloride by fluorine in order to obtain the uranium in the hexafluoride state. Recovery of the uranium contained m various scrap materials is obtained by a conventional refining process combustion of metallic scrap, nitric acid dissolution of the oxide, solvent purification by tributyl phosphate, ammonium diuranate precipitation, calcining, reduction and hydro fluorination into uranium tetrafluoride, bomb reduction by calcium and slag treatment. Two separate workshops operate along these lines one takes care of the uranium with an isotopic enrichment of up to 3 p. 100, the other handles the high enrichments. The handling of each step of this process, bearing in mind the necessity for nuclear safety, has raised some special technological problems and has led to the conception of new apparatus, in particular the roasting furnace for metal turnings, the nitric acid dissolution unit, the continuous precipitator and ever safe filter and dryer for ammonium diuranate, the reduction and hydro fluorination furnace and the slag recovery apparatus These are

Uranium prices approaching a 7 year high

International Nuclear Information System (INIS)

Anon.

1996-01-01

This paper provides a market overview of the uranium market. The spot market activity totaled approximately 1.1 million lbs of U3O8 and equivalent. The restricted uranium spot market price range jumped from a high last month of $12.25 to a low this month of $12.45 There was a more moderate increase in the unrestricted range with this month's low end rising to last month's high of $10.15. Conversion prices remained steady and the lower end of the SWU range rose slightly to $92

Mixed Uranium/Refractory Metal Carbide Fuels for High Performance Nuclear Reactors

International Nuclear Information System (INIS)

Knight, Travis; Anghaie, Samim

2002-01-01

Single phase, solid-solution mixed uranium/refractory metal carbides have been proposed as an advanced nuclear fuel for advanced, high-performance reactors. Earlier studies of mixed carbides focused on uranium and either thorium or plutonium as a fuel for fast breeder reactors enabling shorter doubling owing to the greater fissile atom density. However, the mixed uranium/refractory carbides such as (U, Zr, Nb)C have a lower uranium densities but hold significant promise because of their ultra-high melting points (typically greater than 3700 K), improved material compatibility, and high thermal conductivity approaching that of the metal. Various compositions of (U, Zr, Nb)C were processed with 5% and 10% metal mole fraction of uranium. Stoichiometric samples were processed from the constituent carbide powders, while hypo-stoichiometric samples with carbon-to-metal (C/M) ratios of 0.92 were processed from uranium hydride, graphite, and constituent refractory carbide powders. Processing techniques of cold uniaxial pressing, dynamic magnetic compaction, sintering, and hot pressing were investigated to optimize the processing parameters necessary to produce high density (low porosity), single phase, solid-solution mixed carbide nuclear fuels for testing. This investigation was undertaken to evaluate and characterize the performance of these mixed uranium/refractory metal carbides for high performance, ultra-safe nuclear reactor applications. (authors)

Uranium absorption study pile; Empilement pour le controle de l'absorption de l'uranium

Energy Technology Data Exchange (ETDEWEB)

Raievski, V; Sautiez, B [Commissariat a l' Energie Atomique, Saclay (France).Centre d' Etudes Nucleaires

1959-07-01

The report describes a pile designed to measure the absorption of fuel slugs. The pile is of graphite and comprises a central section composed of uranium rods in a regular lattice. RaBe sources and BF{sub 3} counters are situated on either side of the center. A given uranium charge is compared with a specimen charge of about 560 kg, and the difference in absorption between the two noted. The sensitivity of the equipment will detect absorption variations of about a few ppm boron (10{sup -6} boron per gr. of uranium) or better. (author) [French] Nous decrivons un dispositif permettant de mesurer l'absorption des elements combustibles d'une pile. Ce dispositif est constitue par un empilement de graphite dont la region centrale est formee par un reseau regulier de barres d'uranium. Des sources de RaBe et des compteurs a BF{sub 3} sont places de part et d'autre de cette region. En comparant un chargement d'uranium a un chargement etalon d'environ 560 kg, on peut determiner la difference d'absorption entre ces deux chargements. La sensibilite permettrait de deceler une variation d'absorption de l'ordre du ppm de bore (10{sup -6} g de bore par gramme d'uranium) et peut-etre mieux. (auteur)

Investigation of charge stripping scheme for uranium ions at 1-20 MeV/nucleon

Science.gov (United States)

Kuboki, Hironori; Harada, Hiroyuki; Saha, Pranab K.

2018-05-01

We investigated a possibility to obtain charge distributions of uranium ions under the conditions to meet the requirements of the booster synchrotron proposed for heavy ion acceleration at J-PARC. The charge distribution is expected to have a width as narrow as possible to realize multi-charge acceleration. The main candidate of stripping material is a carbon foil because we can obtain narrower distributions than gas stripper and a lot of data is available. Besides that, the thickness of the stripping material should be less than 142 μg cm-2 because the energy loss in the stripping material would be compensated by an auxiliary accelerating cavity in the synchrotron ring. We studied the impact energy with which the charge distribution attains equilibrium within this thickness and has the narrowest width. The width is estimated over 1-20 MeV/nucleon by the calculation using the ionization and electron capture cross sections. Scaling factors are introduced to reproduce the experimental data and are determined to be 2.0 and 0.08 for the cross sections of ionization and electron capture, respectively. We concluded that the narrowest width can be obtained at 5.5 MeV/nucleon with a 109-μg cm-2-thick carbon foil.

Uranium sorption on tezontle volcanic rock

Energy Technology Data Exchange (ETDEWEB)

Lopez M, B. E.; Duran B, J. M.; Iturbe G, J. L.; Olguin G, M. T., E-mail: beatriz.lopez@inin.gob.m [ININ, Departamento de Quimica, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico)

2009-07-01

It is described a study that demonstrates that hexavalent uranium ions were sorbed by the naturally occurring mineral using a batch technique. This mineral is found in abundant quantities in Mexico. Our study focused on the separation of U Vi from synthetic aqueous systems of both H{sub 2}O-UO{sub 2}(NO{sub 3}){sub 2}.6H{sub 2}O (acid) and H{sub 2}O-Na{sub 4}[UO{sub 2}(CO{sub 3}){sub 3}] (basic). The chemical speciation was performed by using high voltage electrophoresis, and the uranium content was determined by UV-Vis spectroscopy. The quantified U(Vi) sorption by tezontle from acidic and basic systems was 2.72 and 1.68 mumol/g, respectively, and the sorption behavior is discussed considering the surface charge of the tezontle at different ph values based on the point of zero charge characteristic of this material. (Author)

76 FR 72984 - Revised Application for a License To Export High-Enriched Uranium

Science.gov (United States)

2011-11-28

... NUCLEAR REGULATORY COMMISSION Revised Application for a License To Export High-Enriched Uranium The application for a license to export high-enriched Uranium has been revised as noted below. Notice... fabricate fuel France. Security Complex; October 18, Uranium (93.35%). uranium (174.0 elements in France...

78 FR 33448 - Application for a License To Export High-Enriched Uranium

Science.gov (United States)

2013-06-04

... NUCLEAR REGULATORY COMMISSION Application for a License To Export High-Enriched Uranium Pursuant.... Security Complex, May 13, Uranium (93.35%). uranium-235 at the National 2013, May 21, 2013, XSNM3745, contained in 7.5 Research Universal 11006098. kilograms reactor in Canada for uranium. ultimate use in...

Active interrogation of highly enriched uranium

Science.gov (United States)

Fairrow, Nannette Lea

Safeguarding special nuclear material (SNM) in the Department of Energy Complex is vital to the national security of the United States. Active and passive nondestructive assays are used to confirm the presence of SNM in various configurations ranging from waste to nuclear weapons. Confirmation measurements for nuclear weapons are more challenging because the design complicates the detection of a distinct signal for highly enriched uranium. The emphasis of this dissertation was to investigate a new nondestructive assay technique that provides an independent and distinct signal to confirm the presence of highly enriched uranium (HEU). Once completed and tested this assay method could be applied to confirmation measurements of nuclear weapons. The new system uses a 14-MeV neutron source for interrogation and records the arrival time of neutrons between the pulses with a high efficiency detection system. The data is then analyzed by the Feynman reduced variance method. The analysis determined the amount of correlation in the data and provided a unique signature of correlated fission neutrons. Measurements of HEU spheres were conducted at Los Alamos with the new system. Then, Monte Carlo calculations were performed to verify hypothesis made about the behavior of the neutrons in the experiment. Comparisons of calculated counting rates by the Monte Carlo N-Particle Transport Code (MCNP) were made with the experimental data to confirm that the measured response reflected the desired behavior of neutron interactions in the highly enriched uranium. In addition, MCNP calculations of the delayed neutron build-up were compared with the measured data. Based on the results obtained from this dissertation, this measurement method has the potential to be expanded to include mass determinations of highly enriched uranium. Although many safeguards techniques exist for measuring special nuclear material, the number of assays that can be used to confirm HEU in shielded systems is

77 FR 73056 - Application for a License To Export High-Enriched Uranium

Science.gov (United States)

2012-12-07

... NUCLEAR REGULATORY COMMISSION Application for a License To Export High-Enriched Uranium Pursuant... Complex. Uranium (93.2%). uranium-235 at CERCA AREVA Romans October 10, 2012 contained in 6.2 in France and to October 12, 2012 kilograms irradiate targets at XSNM3729 uranium. the BR-2 Research 11006053...

77 FR 73055 - Application for a License To Export High-Enriched Uranium

Science.gov (United States)

2012-12-07

... NUCLEAR REGULATORY COMMISSION Application for a License To Export High-Enriched Uranium Pursuant.... Security Complex. Uranium uranium-235 at CERCA AREVA October 10, 2012 (93.35%). contained in Romans in France October 12, 2012 10.1 kilograms and to irradiate XSNM3730 uranium. targets at the HFR 11006054...

Production, transport and charge capture measurements of highly charged recoil ions

International Nuclear Information System (INIS)

Trebus, U.E.

1989-01-01

An experiment is described to study highly charged recoil ions on-line to the heavy accelerator UNILAC at GSI. The highly charged recoil ions are produced by heavy-ion bombardment of a gas target. Subsequently the slow highly charged recoil ions are extracted from the ionization volume, and guided through a beam transport line to a Wien filter for charge state selection and to a collision region to study charge transfer processes. Several experiments were carried out to show the efficient charge state separation. Charge states up to q = 15 were observed. When using a retarding field analyzer cross sections for single electron capture were determined for different charge states of Xe q+ for q = 4 to 11 and He gas. The experiments demonstrated increasing charge transfer cross sections with increasing charge state q and indicated the effect of near resonant charge capture for q = 6. The flexible data acquisition system used, is described and other future experiments, such as for instance in flight ion-trapping are indicated in the appendix

Production, transport and charge capture measurements of highly charged recoil ions

International Nuclear Information System (INIS)

Trebus, U.E.

1989-05-01

An experiment is described to study highly charged recoil ions on-line to the heavy ion accelerator UNILAC at GSI. The highly charged recoil ions are produced by heavy ion bombardment of a gas target. Subsequently the slow highly charged recoil ions are extracted from the ionization volume, and guided through a beam transport line to a Wien filter for charge state selection and to a collision region to study charge transfer processes. Several experiments were carried out to show the efficient charge state separation. Charge states up to q=15 were observed. When using a retarding field analyzer cross sections for single electron capture were determined for different charge states of Xe q+ for q=4 to 11 and He gas. The experiments demonstrated increasing charge transfer cross sections with increasing charge state q and indicated the effect of near resonant charge capture for q=6. The flexible data acquisition system used, is described and other future experiments, such as for instance in flight ion-trapping are indicated in the appendix. (orig.)

The multiphoton ionization of uranium hexafluoride

International Nuclear Information System (INIS)

Armstrong, D.P.

1992-05-01

Multiphoton ionization (MPI) time-of-flight mass spectroscopy and photoelectron spectroscopy studies of UF 6 have been conducted using focused light from the Nd:YAG laser fundamental (λ=1064 nm) and its harmonics (λ=532, 355, or 266 nm), as well as other wavelengths provided by a tunable dye laser. The MPI mass spectra are dominated by the singly and multiply charged uranium ions rather than by the UF x + fragment ions even at the lowest laser power densities at which signal could be detected. The laser power dependence of U n+ ions signals indicates that saturation can occur for many of the steps required for their ionization. In general, the doubly-charged uranium ion (U 2+ ) intensity is much greater than that of the singly-charged uranium ion (U + ). For the case of the tunable dye laser experiments, the U n+ (n = 1- 4) wavelength dependence is relatively unstructured and does not show observable resonance enhancement at known atomic uranium excitation wavelengths. The dominance of the U 2+ ion and the absence or very small intensities of UF x + fragments, along with the unsaturated wavelength dependence, indicate that mechanisms may exist other than ionization of bare U atoms after the stepwise photodissociation of F atoms from the parent molecule

Underground Milling of High-Grade Uranium Ore

Energy Technology Data Exchange (ETDEWEB)

Edwards, C., E-mail: chuck.edwards@amec.com [AMEC Americas Limited, Saskatoon, Saskatchewan (Canada)

2014-05-15

There are many safety and technical issues involved in the mining and progressing of high grade uranium ores such as those exploited in Northern Canada at present. With more of this type of mine due to commence production in the near future, operators have been looking at ways to better manage the situation. The paper describes underground milling of high-grade uranium ore as a means of optimising production costs and managing safety issues. In addition the paper presents some examples of possible process flowsheets and plant layouts that could be applicable to such operations. Finally an assessment of potential benefits from underground milling from a variety of viewpoints is provided. (author)

Spectroscopic Investigations of Highly Charged Ions using X-Ray Calorimeter Spectrometers

Energy Technology Data Exchange (ETDEWEB)

Thorn, Daniel Bristol [Univ. of California, Davis, CA (United States)

2008-11-19

Spectroscopy of K-shell transitions in highly charged heavy ions, like hydrogen-like uranium, has the potential to yield information about quantum electrodynamics (QED) in extremely strong nuclear fields as well as tests of the standard model, specifically parity violation in atomic systems. These measurements would represent the 'holy grail' in high-Z atomic spectroscopy. However, the current state-of-the-art detection schemes used for recording the K-shell spectra from highly charged heavy ions does not yet have the resolving power to be able to attain this goal. As such, to push the field of high-Z spectroscopy forward, new detectors must be found. Recently, x-ray calorimeter spectrometers have been developed that promise to make such measurements. In an effort to make the first steps towards attaining the 'holy grail', measurements have been performed with two x-ray calorimeter spectrometers (the XRS/EBIT and the ECS) designed and built at Goddard Space Flight Center in Greenbelt, MD. The calorimeter spectrometers have been used to record the K-shell spectra of highly charged ions produced in the SuperEBIT electron beam ion trap at Lawrence Livermore National Laboratory in Livermore, CA. Measurements performed with the XRS/EBIT calorimeter array found that the theoretical description of well-above threshold electron-impact excitation cross sections for hydrogen-like iron and nickel ions are correct. Furthermore, the first high-resolution spectrum of hydrogen-like through carbon-like praseodymium ions was recorded with a calorimeter. In addition, the new high-energy array on the EBIT Calorimeter Spectrometer (ECS) was used to resolve the K-shell x-ray emission spectrum of highly charged xenon ions, where a 40 ppm measurement of the energy of the K-shell resonance transition in helium-like xenon was achieved. This is the highest precision result, ever, for an element with such high atomic number. In addition, a first-of-its-kind measurement of

Spectroscopic Investigations of Highly Charged Ions using X-Ray Calorimeter Spectrometers

International Nuclear Information System (INIS)

Thorn, D. B.

2008-01-01

Spectroscopy of K-shell transitions in highly charged heavy ions, like hydrogen-like uranium, has the potential to yield information about quantum electrodynamics (QED) in extremely strong nuclear fields as well as tests of the standard model, specifically parity violation in atomic systems. These measurements would represent the 'holy grail' in high-Z atomic spectroscopy. However, the current state-of-the-art detection schemes used for recording the K-shell spectra from highly charged heavy ions does not yet have the resolving power to be able to attain this goal. As such, to push the field of high-Z spectroscopy forward, new detectors must be found. Recently, x-ray calorimeter spectrometers have been developed that promise to make such measurements. In an effort to make the first steps towards attaining the 'holy grail', measurements have been performed with two x-ray calorimeter spectrometers (the XRS/EBIT and the ECS) designed and built at Goddard Space Flight Center in Greenbelt, MD. The calorimeter spectrometers have been used to record the K-shell spectra of highly charged ions produced in the SuperEBIT electron beam ion trap at Lawrence Livermore National Laboratory in Livermore, CA. Measurements performed with the XRS/EBIT calorimeter array found that the theoretical description of well-above threshold electron-impact excitation cross sections for hydrogen-like iron and nickel ions are correct. Furthermore, the first high-resolution spectrum of hydrogen-like through carbon-like praseodymium ions was recorded with a calorimeter. In addition, the new high-energy array on the EBIT Calorimeter Spectrometer (ECS) was used to resolve the K-shell x-ray emission spectrum of highly charged xenon ions, where a 40 ppm measurement of the energy of the K-shell resonance transition in helium-like xenon was achieved. This is the highest precision result, ever, for an element with such high atomic number. In addition, a first-of-its-kind measurement of the effect of the

The technology of uranium extraction from the brine with high chlorine-ion content

International Nuclear Information System (INIS)

Khakimov, N.; Nazarov, Kh.M.; Mirsaidov, I.U.; Negmatov, Sh.I.; Barotov, B.B.

2010-01-01

Present article is devoted to technology of uranium extraction from the brine with high chlorine-ion content. The research results on uranium extraction from the brine of Sasik-Kul Lake by means of sorption method were considered. The chemical composition of salt was determined. The process of uranium sorption was described and analyzed. The technology of uranium extraction from the brine with high chlorine-ion content was proposed.

Cation-mediated conversion of the state of charge in uranium arene inverted-sandwich complexes

Energy Technology Data Exchange (ETDEWEB)

Camp, Clement; Mougel, Victor; Pecaut, Jacques; Mazzanti, Marinella [Laboratoire de Reconnaissance Ionique et Chimie de Coordination, SCIB, UMR-E3 CEA-UJF, INAC, CEA-Grenoble (France); Maron, Laurent [LCPNO, CNRS and INSA, UPS, Universite de Toulouse (France)

2013-12-16

Two new arene inverted-sandwich complexes of uranium supported by siloxide ancillary ligands [K{U(OSi(OtBu)_3)_3}{sub 2}(μ-η{sup 6}:η{sup 6}-C{sub 7}H{sub 8})] (3) and [K{sub 2}{U(OSi(OtBu)_3)_3}{sub 2}(μ-η{sup 6}:η{sup 6}-C{sub 7}H{sub 8})] (4) were synthesized by the reduction of the parent arene-bridged complex [{U(OSi(OtBu)_3)_3}{sub 2}(μ-η{sup 6}:η{sup 6}-C{sub 7}H{sub 8})] (2) with stoichiometric amounts of KC{sub 8} yielding a rare family of inverted-sandwich complexes in three states of charge. The structural data and computational studies of the electronic structure are in agreement with the presence of high-valent uranium centers bridged by a reduced tetra-anionic toluene with the best formulation being U{sup V}-(arene{sup 4-})-U{sup V}, KU{sup IV}-(arene{sup 4-})-U{sup V}, and K{sub 2}U{sup IV}-(arene{sup 4-})-U{sup IV} for complexes 2, 3, and 4 respectively. The potassium cations in complexes 3 and 4 are coordinated to the siloxide ligands both in the solid state and in solution. The addition of KOTf (OTf=triflate) to the neutral compound 2 promotes its disproportionation to yield complexes 3 and 4 (depending on the stoichiometry) and the U{sup IV} mononuclear complex [U(OSi(OtBu){sub 3}){sub 3}(OTf)(thf){sub 2}] (5). This unprecedented reactivity demonstrates the key role of potassium for the stability of these complexes. (Copyright copyright 2013 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Recovery of uranium from seawater using amidoxime hollow fibers

International Nuclear Information System (INIS)

Saito, K.; Uezu, K.; Hori, T.; Furusaki, S.; Sugo, T.; Okamoto, J.

1988-01-01

A novel amidoxime-group-containing adsorbent of hollow-fiber form (AO-H fiber) was prepared by radiation-induced graft polymerization of acrylonitrile onto a polyethylene hollow fiber, followed by chemical conversion of the produced cyano group to an amidoxime group. Distribution of the amidoxime group was uniform throughout hollow-fiber membrane. The fixed-bed adsorption column, 30 cm in length and charged with the bundle of AO-H fibers, was found to adsorb uranium from natural seawater at a sufficiently high rate: 0.66 mg uranium per g of adsorbent in 25 days

HIGH LEVELS OF URANIUM IN GROUNDWATER OF ULAANBAATAR, MONGOLIA

Science.gov (United States)

Nriagu, Jerome; Nam, Dong-Ha; Ayanwola, Titilayo A.; Dinh, Hau; Erdenechimeg, Erdenebayar; Ochir, Chimedsuren; Bolormaa, Tsend-Ayush

2011-01-01

Water samples collected from 129 wells in seven of the nine sub-divisions of Ulaanbaatar were analyzed by inductively coupled plasma mass spectrometry (ICP-MS) using Clean Lab methods. The levels of many trace elements were found to be very low with the average concentrations (ranges in brackets) being 0.9 (uranium were surprisingly elevated (mean, 4.6 μg/L; range uranium in drinking water. Local rocks and soils appear to be the natural source of the uranium. The levels of uranium in Ulaanbaatar's groundwater are in the range that has been associated with nephrotoxicity, high blood pressure, bone dysfunction and likely reproductive impairment in human populations. We consider the risk associated with drinking the groundwater with elevated levels of uranium in Ulaanbaatar to be a matter for some public health concern and conclude that the paucity of data on chronic effects of low level exposure is a risk factor for continuing the injury to many people in this city. PMID:22142646

78 FR 16303 - Request To Amend a License To Export; High-Enriched Uranium

Science.gov (United States)

2013-03-14

... NUCLEAR REGULATORY COMMISSION Request To Amend a License To Export; High-Enriched Uranium Pursuant to 10 CFR 110.70 (b) ``Public Notice of Receipt of an Application,'' please take notice that the... Application No. Docket No. U.S. Department of Energy, High-Enriched Uranium 10 kilograms uranium To...

High throughput salt separation from uranium deposits

Energy Technology Data Exchange (ETDEWEB)

Kwon, S.W.; Park, K.M.; Kim, J.G.; Kim, I.T.; Park, S.B., E-mail: swkwon@kaeri.re.kr [Korea Atomic Energy Research Inst. (Korea, Republic of)

2014-07-01

It is very important to increase the throughput of the salt separation system owing to the high uranium content of spent nuclear fuel and high salt fraction of uranium dendrites in pyroprocessing. Multilayer porous crucible system was proposed to increase a throughput of the salt distiller in this study. An integrated sieve-crucible assembly was also investigated for the practical use of the porous crucible system. The salt evaporation behaviors were compared between the conventional nonporous crucible and the porous crucible. Two step weight reductions took place in the porous crucible, whereas the salt weight reduced only at high temperature by distillation in a nonporous crucible. The first weight reduction in the porous crucible was caused by the liquid salt penetrated out through the perforated crucible during the temperature elevation until the distillation temperature. Multilayer porous crucibles have a benefit to expand the evaporation surface area. (author)

Basic research on high-uranium density fuels for research and test reactors

International Nuclear Information System (INIS)

Ugajin, M.; Itoh, A.; Akabori, M.

1992-01-01

High-uranium density fuels, uranium silicides (U 3 Si 2 , U 3 Si) and U 6 Me-type uranium alloys (Me = Fe, Mn, Ni), were prepared and examined metallurgically as low-enriched uranium (LEU) fuels for research and test reactors. Miniature aluminum-dispersion plate-type fuel (miniplate) and aluminum-clad disk-type fuel specimens were fabricated and subjected to the neutron irradiation in JMTR (Japan Materials Testing Reactor). Fuel-aluminum compatibility tests were conducted to elucidate the extent of reaction and to identify reaction products. The relative stability of the fuels in an aluminum matrix was established at 350degC or above. Experiments were also performed to predict the chemical form of the solid fission-products in the uranium silicide (U 3 Si 2 ) simulating a high burnup anticipated for reactor service. (author)

Multilayer Porous Crucibles for the High Throughput Salt Separation from Uranium Deposits

International Nuclear Information System (INIS)

Kwon, S. W.; Park, K. M.; Kim, J. G.; Kim, I. T.; Seo, B. K.; Moon, J. G.

2013-01-01

Solid cathode processing is necessary to separate the salt from the cathode since the uranium deposit in a solid cathode contains electrolyte salt. A physical separation process, such as a distillation separation, is more attractive than a chemical or dissolution process because physical processes generate much less secondary process. Distillation process was employed for the cathode processsing due to the advantages of minimal generation of secondary waste, compact unit process, simple and low cost equipment. The basis for vacuum distillation separation is the difference in vapor pressures between salt and uranium. A solid cathode deposit is heated in a heating region and salt vaporizes, while nonvolatile uranium remains behind. It is very important to increase the throughput of the salt separation system owing to the high uranium content of spent nuclear fuel and high salt fraction of uranium dendrites. The evaporation rate of the LiCl-KCl eutectic salt in vacuum distiller is not so high to come up with the generation capacity of uranium dendrites in an electro-refiner. Therefore, a wide evaporation area or high distillation temperature is necessary for the successful salt separation. In this study, it was attempted to enlarge a throughput of the salt distiller with a multilayer porous crucibles for the separation of adhered salt in the uranium deposits generated from the electrorefiner. The feasibility of the porous crucibles was tested by the salt distillation experiments. In this study, the salt distiller with multilayer porous crucibles was proposed and the feasibility of liquid salt separation was examined to increase a throughput. It was found that the effective separation of salt from uranium deposits was possible by the multilayer porous crucibles

Multilayer Porous Crucibles for the High Throughput Salt Separation from Uranium Deposits

Energy Technology Data Exchange (ETDEWEB)

Kwon, S. W.; Park, K. M.; Kim, J. G.; Kim, I. T.; Seo, B. K.; Moon, J. G. [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2013-05-15

Solid cathode processing is necessary to separate the salt from the cathode since the uranium deposit in a solid cathode contains electrolyte salt. A physical separation process, such as a distillation separation, is more attractive than a chemical or dissolution process because physical processes generate much less secondary process. Distillation process was employed for the cathode processsing due to the advantages of minimal generation of secondary waste, compact unit process, simple and low cost equipment. The basis for vacuum distillation separation is the difference in vapor pressures between salt and uranium. A solid cathode deposit is heated in a heating region and salt vaporizes, while nonvolatile uranium remains behind. It is very important to increase the throughput of the salt separation system owing to the high uranium content of spent nuclear fuel and high salt fraction of uranium dendrites. The evaporation rate of the LiCl-KCl eutectic salt in vacuum distiller is not so high to come up with the generation capacity of uranium dendrites in an electro-refiner. Therefore, a wide evaporation area or high distillation temperature is necessary for the successful salt separation. In this study, it was attempted to enlarge a throughput of the salt distiller with a multilayer porous crucibles for the separation of adhered salt in the uranium deposits generated from the electrorefiner. The feasibility of the porous crucibles was tested by the salt distillation experiments. In this study, the salt distiller with multilayer porous crucibles was proposed and the feasibility of liquid salt separation was examined to increase a throughput. It was found that the effective separation of salt from uranium deposits was possible by the multilayer porous crucibles.

78 FR 72123 - Request To Amend a License to Export High-Enriched Uranium

Science.gov (United States)

2013-12-02

... NUCLEAR REGULATORY COMMISSION Request To Amend a License to Export High-Enriched Uranium Pursuant... manufacture HEU targets in Belgium. National Nuclear Security Uranium (HEU) uranium France for irradiation in... 5.8 kg of U- 235 contained in 6.2 kg uranium to a new cumulative total of 12.615 kg of U-235...

75 FR 15743 - Application for a License To Export High-Enriched Uranium

Science.gov (United States)

2010-03-30

... NUCLEAR REGULATORY COMMISSION Application for a License To Export High-Enriched Uranium Pursuant to 10 CFR 110.70(c) ``Public notice of receipt of an application,'' please take notice that the...-Enriched 160.0 kilograms To fabricate fuel France. Complex, March 3, 2010. Uranium (93.35%). uranium (149...

75 FR 6223 - Application For a License To Export High-Enriched Uranium

Science.gov (United States)

2010-02-08

... NUCLEAR REGULATORY COMMISSION Application For a License To Export High-Enriched Uranium Pursuant to 10 CFR 110.70(c) ``Public notice of receipt of an application,'' please take notice that the..., Uranium (93.35%). uranium (16.3 targets for December 28, 2009, XSNM3623, kilograms U-235). irradiation in...

77 FR 1956 - Application for a License To Export High-Enriched Uranium

Science.gov (United States)

2012-01-12

... NUCLEAR REGULATORY COMMISSION Application for a License To Export High-Enriched Uranium Pursuant to 10 CFR 110.70(b) ``Public Notice of Receipt of an Application,'' please take notice that the.... Security Complex. Uranium uranium (9.3 targets at December 21, 2011 (93.35%). kilograms U- CERCA AREVA...

75 FR 7525 - Application for a License To Export High-Enriched Uranium

Science.gov (United States)

2010-02-19

... NUCLEAR REGULATORY COMMISSION Application for a License To Export High-Enriched Uranium Pursuant to 10 CFR 110.70(c) ``Public notice of receipt of an application,'' please take notice that the..., February 2, Uranium (93.35%). uranium (87.3 elements in 2010, February 2, 2010, kilograms U-235). France...

In situ spectroscopy and spectroelectrochemistry of uranium in high-temperature alkali chloride molten salts.

Science.gov (United States)

Polovov, Ilya B; Volkovich, Vladimir A; Charnock, John M; Kralj, Brett; Lewin, Robert G; Kinoshita, Hajime; May, Iain; Sharrad, Clint A

2008-09-01

Soluble uranium chloride species, in the oxidation states of III+, IV+, V+, and VI+, have been chemically generated in high-temperature alkali chloride melts. These reactions were monitored by in situ electronic absorption spectroscopy. In situ X-ray absorption spectroscopy of uranium(VI) in a molten LiCl-KCl eutectic was used to determine the immediate coordination environment about the uranium. The dominant species in the melt was [UO 2Cl 4] (2-). Further analysis of the extended X-ray absorption fine structure data and Raman spectroscopy of the melts quenched back to room temperature indicated the possibility of ordering beyond the first coordination sphere of [UO 2Cl 4] (2-). The electrolytic generation of uranium(III) in a molten LiCl-KCl eutectic was also investigated. Anodic dissolution of uranium metal was found to be more efficient at producing uranium(III) in high-temperature melts than the cathodic reduction of uranium(IV). These high-temperature electrolytic processes were studied by in situ electronic absorption spectroelectrochemistry, and we have also developed in situ X-ray absorption spectroelectrochemistry techniques to probe both the uranium oxidation state and the uranium coordination environment in these melts.

Charged Particle Radiography

International Nuclear Information System (INIS)

Morris, Chris

2004-01-01

The Coulomb multiple scattering of charged particles as they pass through material allows them to be used as a radiographic probe. This forms the basis for a new kind of radiography that is finding application where conventional x-ray radiography is limited by flux or backgrounds. Charged-particle radiography is providing a versatile new probe that has advantages over conventional x-ray radiography for some unique application. Proton radiography has been used to make quantitative motion pictures of high explosive driven experiments and proves to be of great value for radiographing experiments that mock up nuclear weapon primaries for stockpile certification. By taking advantage of magnetic lens to magnify images and by using the very bright beams that can be made with electrons, charged-particle radiography may be useful for studying the fine spatial detail and very fast motion in laser driven implosion experiments at the National Ignition Facility. Finally, radiographs can be made using cosmic-ray muons for searching vehicles and cargo containers for surreptitious cargo of high z materials such as uranium or plutonium.

Low-enriched uranium high-density target project. Compendium report

Energy Technology Data Exchange (ETDEWEB)

Vandegrift, George; Brown, M. Alex; Jerden, James L.; Gelis, Artem V.; Stepinski, Dominique C.; Wiedmeyer, Stanley; Youker, Amanda; Hebden, Andrew; Solbrekken, G; Allen, C; Robertson., D; El-Gizawy, Sherif; Govindarajan, Srisharan; Hoyer, Annemarie; Makarewicz, Philip; Harris, Jacob; Graybill, Brian; Gunn, Andy; Berlin, James; Bryan, Chris; Sherman, Steven; Hobbs, Randy; Griffin, F. P.; Chandler, David; Hurt, C. J.; Williams, Paul; Creasy, John; Tjader, Barak; McFall, Danielle; Longmire, Hollie

2016-09-01

At present, most ⁹⁹Mo is produced in research, test, or isotope production reactors by irradiation of highly enriched uranium targets. To achieve the denser form of uranium needed for switching from high to low enriched uranium (LEU), targets in the form of a metal foil (~125-150 µm thick) are being developed. The LEU High Density Target Project successfully demonstrated several iterations of an LEU-fission-based Mo-99 technology that has the potential to provide the world’s supply of Mo-99, should major producers choose to utilize the technology. Over 50 annular high density targets have been successfully tested, and the assembly and disassembly of targets have been improved and optimized. Two target front-end processes (acidic and electrochemical) have been scaled up and demonstrated to allow for the high-density target technology to mate up to the existing producer technology for target processing. In the event that a new target processing line is started, the chemical processing of the targets is greatly simplified. Extensive modeling and safety analysis has been conducted, and the target has been qualified to be inserted into the High Flux Isotope Reactor, which is considered above and beyond the requirements for the typical use of this target due to high fluence and irradiation duration.

78 FR 60928 - Request To Amend a License To Export High-Enriched Uranium

Science.gov (United States)

2013-10-02

... NUCLEAR REGULATORY COMMISSION Request To Amend a License To Export High-Enriched Uranium Pursuant... manufacture HEU The Netherlands. National Nuclear Security Uranium uranium (17.1 targets in France... export from 9.4 kg of U-235 contained in 10.1 kg uranium to a new cumulative total of 17.1 kg of U-235...

Uranium oxide recovering method

International Nuclear Information System (INIS)

Ota, Kazuaki; Takazawa, Hiroshi; Teramae, Naoki; Onoue, Takeshi.

1997-01-01

Nitrates containing uranium nitrate are charged in a molten salt electrolytic vessel, and a heat treatment is applied to prepare molten salts. An anode and a cathode each made of a graphite rod are disposed in the molten salts. AC voltage is applied between the anode and the cathode to conduct electrolysis of the molten salts. Uranium oxides are deposited as a recovered product of uranium, on the surface of the anode. The nitrates containing uranium nitrate are preferably a mixture of one or more nitrates selected from sodium nitrate, potassium nitrate, calcium nitrate and magnesium nitrate with uranium nitrate. The nitrates may be liquid wastes of nitrates. The temperature for the electrolysis of the molten salts is preferably from 150 to 300degC. The voltage for the electrolysis of the molten salts is preferably an AC voltage of from 2 to 6V, more preferably from 4 to 6V. (I.N.)

Midwest Joint Venture high-grade uranium mining

International Nuclear Information System (INIS)

Fredrickson, H.K.

1992-01-01

Midwest Joint Venture (MJV) owns a high-grade uranium deposit in northern Saskatchewan. The deposit is located too deep below surface to be mined economically by open pit methods, and as a consequence, present plans are that it will be mined by underground methods. High-grade uranium ore of the type at MJV, encased in weak, highly altered ground and with radon-rich water inflows, has not before been mined by underground methods. The test mining phase of the project, completed in 1989, had three objectives: To evaluate radiation protection requirements associated with the handling of large quantities of radon-rich water and mining high-grade uranium ore in an underground environment; to investigate the quantity and quality of water inflows into the mine; and, to investigate ground conditions in and around the ore zone as an aid in determining the production mining method to be used. With information gained from the test mining project, a mining method for the production mine has been devised. Level plans have been drawn up, ventilation system designed, pumping arrangements made and methods of ore handling considered. All this is to be done in a manner that will be safe for those doing the work underground. Some of the mining methods planned are felt to be unique in that they are designed to cope with mining problems not known to have been encountered before. New problems underground have required new methods to handle them. Remote drilling, blasting, mucking and backfilling form the basis of the planned mining method

Westinghouse says cartel rigged U.S. uranium market

International Nuclear Information System (INIS)

Anon.

1976-01-01

On Oct. 15, 1976, Westinghouse filed a complaint in Federal court in Chicago charging that 29 U.S. and foreign uranium producers damaged Westinghouse by illegally rigging the uranium market; they also link the Atomic Industrial Forum to the U.S. activities of this cartel. Background information is presented for the charge, which has become the focal point of Westinghouse's defense against the uranium supply breach of contract suits filed against the firm by 27 electric utilities (3 filed in county court in Pittsburgh, 24 jointly in Federal court in Virginia). Westinghouse attorneys say that most of the evidence they have shows the existence of a cartel in the past, but they hope to show it is still operating in the U.S

Choice and utilization of slightly enriched uranium fuel for high performance research reactors

International Nuclear Information System (INIS)

Cerles, J.M.; Schwartz, J.P.

1978-01-01

Problems relating to the replacement of highly enriched (90% or 93% U 235 ) uranium fuel: by moderately enriched (20% or 40% in U 235 ) metallic uranium fuel and slightly enriched (3% or 8% in U 235 ) uranium oxide fuel are discussed

Desert pioneers go high tech in uranium project

International Nuclear Information System (INIS)

1988-01-01

The Kintyre uranium deposit discovered in 1985 in Western Australia's Great Sandy Desert by CRA Exploration is a highly competitive, easy to mine deposit, estimated at 35,000 tonnes of uranium oxide. Since its discovery CRA has spent $20 million on evaluation drilling and exploration and will spend another $10 million in 1988. Despite its remoteness the latest technology is being used, with sophisticated computer and assaying facilities, including an automatic X-ray fluorescence spectrometer, being established on site. A CRA-built radiometric ore sorter is being tested there which could cut ore processing costs

Use of highly enriched uranium at the FRM-II

Energy Technology Data Exchange (ETDEWEB)

Boening, K. [Forschungs-Neutronenquelle FRM-II, Technische Universitaet Muenchen, D-85747 Garching bei Muenchen (Germany)

2002-07-01

The new FRM-II research reactor in Munich, Germany, provides a high flux of thermal neutrons outside of the core at only 20 MW power. This is achieved by using a single compact, cylindrical fuel element with highly enriched uranium (HEU) which is cooled by light water and placed in the center of a large heavy water tank. The paper outlines the arguments which have led to this core concept and summarizes its performance. It also reports on alternative studies which have been performed for the case of low enriched uranium (LEU) and compares the data of the two concepts, with the conclusion that the FRM-II cannot be converted to LEU. A concept using medium enriched uranium (MEU) is described as well as plans to develop such a fuel element in the future. Finally, it is argued that the use of HEU fuel elements at the FRM-II does not - realistically -involve any risk of proliferation. (author)

Study of uranium dioxyde sputtering induced by multicharged heavy ions at low and very low kinetic energy: projectile charge effect

International Nuclear Information System (INIS)

Haranger, F.

2003-12-01

Ion beam irradiation of a solid can lead to the emission of neutral or ionized atoms, molecules or clusters from the surface. This comes as a result of the atomic motion in the vicinity of the surface, induced by the transfer of the projectile energy. Then, the study of the sputtering process appears as a means to get a better understanding of the excited matter state around the projectile trajectory. In the case of slow multicharged ions, a strong electronic excitation can be achieved by the projectile neutralization above the solid surface and / or its deexcitation below the surface. Parallel to this, the slowing down of such ions is essentially related to elastic collision with the target atoms. The study of the effect of the initial charge state of slow multicharged ions, in the sputtering process, has been carried out by measuring the absolute angular distributions of emission of uranium atoms from a uranium dioxide surface. The experiments have been performed in two steps. First, the emitted particles are collected onto a substrate during irradiation. Secondly, the surface of the collectors is analyzed by Rutherford Backscattering Spectrometry (RBS). This method allows the characterization of the emission of neutrals, which are the vast majority of the sputtered particles. The results obtained provide an access to the evolution of the sputtering process as a function of xenon projectile ions charge state. The measurements have been performed over a wide kinetic energy range, from 81 down to 1.5 keV. This allowed a clear separation of the contribution of the kinetic energy and initial projectile charge state to the sputtering phenomenon. (author)

Compact reaction cell for homogenizing and down-blending highly enriched uranium metal

Science.gov (United States)

McLean, W. II; Miller, P.E.; Horton, J.A.

1995-05-02

The invention is a specialized reaction cell for converting uranium metal to uranium oxide. In a preferred form, the reaction cell comprises a reaction chamber with increasing diameter along its length (e.g. a cylindrical chamber having a diameter of about 2 inches in a lower portion and having a diameter of from about 4 to about 12 inches in an upper portion). Such dimensions are important to achieve the necessary conversion while at the same time affording criticality control and transportability of the cell and product. The reaction chamber further comprises an upper port and a lower port, the lower port allowing for the entry of reactant gases into the reaction chamber, the upper port allowing for the exit of gases from the reaction chamber. A diffuser plate is attached to the lower port of the reaction chamber and serves to shape the flow of gas into the reaction chamber. The reaction cell further comprises means for introducing gases into the reaction chamber and a heating means capable of heating the contents of the reaction chamber. The present invention also relates to a method for converting uranium metal to uranium oxide in the reaction cell of the present invention. The invention is useful for down-blending highly enriched uranium metal by the simultaneous conversion of highly enriched uranium metal and natural or depleted uranium metal to uranium oxide within the reaction cell. 4 figs.

Compact reaction cell for homogenizing and down-blanding highly enriched uranium metal

Science.gov (United States)

McLean, II, William; Miller, Philip E.; Horton, James A.

1995-01-01

The invention is a specialized reaction cell for converting uranium metal to uranium oxide. In a preferred form, the reaction cell comprises a reaction chamber with increasing diameter along its length (e.g. a cylindrical chamber having a diameter of about 2 inches in a lower portion and having a diameter of from about 4 to about 12 inches in an upper portion). Such dimensions are important to achieve the necessary conversion while at the same time affording criticality control and transportability of the cell and product. The reaction chamber further comprises an upper port and a lower port, the lower port allowing for the entry of reactant gasses into the reaction chamber, the upper port allowing for the exit of gasses from the reaction chamber. A diffuser plate is attached to the lower port of the reaction chamber and serves to shape the flow of gas into the reaction chamber. The reaction cell further comprises means for introducing gasses into the reaction chamber and a heating means capable of heating the contents of the reaction chamber. The present invention also relates to a method for converting uranium metal to uranium oxide in the reaction cell of the present invention. The invention is useful for down-blending highly enriched uranium metal by the simultaneous conversion of highly enriched uranium metal and natural or depleted uranium metal to uranium oxide within the reaction cell.

31 CFR 540.317 - Uranium feed; natural uranium feed.

Science.gov (United States)

2010-07-01

... 31 Money and Finance: Treasury 3 2010-07-01 2010-07-01 false Uranium feed; natural uranium feed... (Continued) OFFICE OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY HIGHLY ENRICHED URANIUM (HEU) AGREEMENT ASSETS CONTROL REGULATIONS General Definitions § 540.317 Uranium feed; natural uranium feed. The...

78 FR 17942 - Request To Amend a License To Export High-Enriched Uranium

Science.gov (United States)

2013-03-25

... NUCLEAR REGULATORY COMMISSION Request To Amend a License To Export High-Enriched Uranium Pursuant... Administration. Enriched Uranium contained in 99.7 Reactor in the be processed for March 6, 2013 (93.35%)) kilograms Czech Republic to medical isotope March 11, 2013 uranium) the list of production at the XSNM3622...

PROCESSES OF CHLORINATION OF URANIUM OXIDES

Science.gov (United States)

Rosenfeld, S.

1958-09-16

An improvement is described in the process fur making UCl/sub 4/ from uranium oxide and carbon tetrachloride. In that process, oxides of uranium are contacted with carbon tetrachloride vapor at an elevated temperature. It has been fuund that the reaction product and yield are improved if the uranlum oxide charge is disposed in flat trays in the reaction zone, to a depth of not more than 1/2 centimeter.

Distribution of uranium supply and enrichment

International Nuclear Information System (INIS)

Bamford, F.W.

1982-01-01

Uranium supply and demand is examined from the perspective of companies in the uranium hexafluoride (UF6) conversion business whose main interest is their sources of uranium supply and UF6 destinations because of transportation costs. Because of the variations in yellowcake transport, charges for conversion, and UF6 transport costs, most converters don't have standard prices. Companies try to look ahead to determine patterns of supplies and delivery points when they analyze the market and estimate future prices. Market analyses must take into account the purchasing policies of utilities around the world. The presentation shows North America supplying about 40% of world uranium, with about 13% of the enrichment done elsewhere. It also shows North American converters getting 53% of the business, but that will require importing uranium from outside North America. 6 tables

Space-charge compensation of highly charged ion beam from laser ion source

International Nuclear Information System (INIS)

Kondrashev, S.A.; Collier, J.; Sherwood, T.R.

1996-01-01

The problem of matching an ion beam delivered by a high-intensity ion source with an accelerator is considered. The experimental results of highly charged ion beam transport with space-charge compensation by electrons are presented. A tungsten thermionic cathode is used as a source of electrons for beam compensation. An increase of ion beam current density by a factor of 25 is obtained as a result of space-charge compensation at a distance of 3 m from the extraction system. The process of ion beam space-charge compensation, requirements for a source of electrons, and the influence of recombination losses in a space-charge-compensated ion beam are discussed. (author)

Surface charge compensation for a highly charged ion emission microscope

International Nuclear Information System (INIS)

McDonald, J.W.; Hamza, A.V.; Newman, M.W.; Holder, J.P.; Schneider, D.H.G.; Schenkel, T.

2003-01-01

A surface charge compensation electron flood gun has been added to the Lawrence Livermore National Laboratory (LLNL) highly charged ion (HCI) emission microscope. HCI surface interaction results in a significant charge residue being left on the surface of insulators and semiconductors. This residual charge causes undesirable aberrations in the microscope images and a reduction of the Time-Of-Flight (TOF) mass resolution when studying the surfaces of insulators and semiconductors. The benefits and problems associated with HCI microscopy and recent results of the electron flood gun enhanced HCI microscope are discussed

Use of highly enriched uranium in the material testing reactor BR2

International Nuclear Information System (INIS)

Beeckmans de West-Meerbeeck, A.

1979-05-01

In the material testing reactor BR2, the use of highly enriched uranium is determined by the consideration of the fast, epithermal and thermal neutron flux effectively available for the experimental devices. The choice of the core configuration is defined by combining the localisation of the experimental devices and of fuel elements of various burnup, such as to satisfy the irradiation conditions of the experimental load, compatible with an economic use of the fuel elements and safe operation of the reactor. Taking into account the present manufacturing technology for MTR fuels (37 Wt % uranium density in the fuel meat) the highly enriched uranium cannot be avoided; if higher concentration of uranium could be realised by some new manufacturing technology, the 235 U density of fuel elements at elimination should be kept at the required level and the enrichment could be reduced accordingly

Use of highly enriched uranium in the material testing reactor BR2

International Nuclear Information System (INIS)

Beeckmans de West-Meerbeeck, A.

1979-05-01

In the material testing reactor BR2, the use of highly enriched uranium is determined by the consideration of the fast, epithermal and thermal neutron flux effectively available for the experimental devices. The choice of the core configuration is defined by combining the localisation of the experimental devices and of fuel elements of various burnup, such as to satisfy the irradiation conditions of the experimental load, compatible with an economic use of the fuel elements and safe operation of the reactor. Taking into account the present manufacturing technology for MTR fuels (37 Wt % uranium density in the fuel meat) the highly enriched uranium cannot be avoided: if higher concentration of uranium could be realised by some new manufacturing technology, the 235 U density of fuel elements at elimination should be kept at the required level and the enrichment could be reduced accordingly. (author)

High levels of uranium in groundwater of Ulaanbaatar, Mongolia

Energy Technology Data Exchange (ETDEWEB)

Nriagu, Jerome, E-mail: stoten@umich.edu [Department of Environmental Health Sciences, School of Public Health, University of Michigan, Ann Arbor, MI 48109 (United States); Nam, Dong-Ha; Ayanwola, Titilayo A. [Department of Environmental Health Sciences, School of Public Health, University of Michigan, Ann Arbor, MI 48109 (United States); Dinh, Hau [College of Literature, Science and Arts, University of Michigan (United States); Erdenechimeg, Erdenebayar; Ochir, Chimedsuren [Department Of Preventive Medicine, School Of Public Health, Health Science University, Mongolia, Ulaanbaatar (Mongolia); Bolormaa, Tsend-Ayush [Central Water Laboratory of Water Supply and Sewerage Authority (USUG), Ulaanbaatar (Mongolia)

2012-01-01

Water samples collected from 129 wells in seven of the nine sub-divisions of Ulaanbaatar were analyzed by inductively coupled plasma mass spectrometry (ICP-MS) using Clean Lab methods. The levels of many trace elements were found to be low with the average concentrations (ranges in brackets) being 0.9 (< 0.1-7.9) {mu}g/L for As; 7.7 (0.12-177) {mu}g/L for Mn; 0.2 (< 0.05-1.9) {mu}g/L for Co; 16 (< 0.1-686) {mu}g/L for Zn; 0.7 (< 0.1-1.8) {mu}g/L for Se; < 0.1 (< 0.02-0.69) {mu}g/L for Cd; and 1.3 (< 0.02-32) {mu}g/L for Pb. The levels of uranium were surprisingly elevated (mean, 4.6 {mu}g/L; range < 0.01-57 {mu}g/L), with the values for many samples exceeding the World Health Organization's guideline of 15 {mu}g/L for uranium in drinking water. Local rocks and soils appear to be the natural source of the uranium. The levels of uranium in Ulaanbaatar's groundwater are in the range that has been associated with nephrotoxicity, high blood pressure, bone dysfunction and likely reproductive impairment in human populations. We consider the risk associated with drinking the groundwater with elevated levels of uranium in Ulaanbaatar to be a matter for some public health concern and conclude that the paucity of data on chronic effects of low level exposure is a risk factor for continuing the injury to many people in this city. - Highlights: Black-Right-Pointing-Pointer We analyzed water samples from wells across the city of Ulaanbaatar, Mongolia for total uranium along with arsenic, manganese, cobalt, zinc, selenium, cadmium and lead. Black-Right-Pointing-Pointer We found that compared to other trace metals and metalloids, the levels of uranium were surprisingly elevated with the values for many samples exceeding the World Health Organization's guideline for drinking water. Black-Right-Pointing-Pointer Local rocks and soils appear to be the natural source of the uranium. Black-Right-Pointing-Pointer The health risk associated with drinking the groundwater

Solid state processing of massive uranium mononitride, using uranium and uranium higher nitride powders as starting materials (1962); Preparation a l'etat solide de mononitrure d'uranium massif a partir de poudres d'uranium et de nitrures superieurs d'uranium (1962)

Energy Technology Data Exchange (ETDEWEB)

Molinari, J [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1960-12-15

The mechanism and the optimum conditions for preparing uranium mononitride have been studied. The results have been used for hot pressing (250 kg/cm{sup 2}, 1000 deg. C, under vacuum) a mixture of powders of uranium and uranium higher nitrides. The products obtained have been identified by X-ray measurements and may be - at will and depending upon the stoichiometry - either UN, or a cermet a U{sub {alpha}}-UN. As revealed by the curved shape of grain boundaries, the sinters obtained here do not easily evolve towards physico-chemical equilibrium when submitted to heat treatment. This behaviour is quite different from the one observed with uranium monocarbide prepared by a similar method. This fact may be ascribed to the insolubility in the matrix UN of particles of UO{sub 2} being present as impurities. The density, hardness and thermal conductivity of these products are higher than those measured on uranium nitride or cermets U-UN obtained by other methods. (author) [French] Apres une etude prealable du mecanisme et des conditions optimales de nitruration de l'uranium, on a montre qu'il est possible de preparer par frittage sous charge (250 kg/cm{sup 2}, 1000 deg. C sous vide) d'un melange de poudres d'uranium et de nitrures superieurs d'uranium, un produit qui a ete identifie par diffraction de rayons X. On peut ainsi obtenir a volonte, soit le monocarbure UN, soit un cermet U{sub {alpha}}-UN dans le cas de compositions sous-stoechiometriques. Au contraire du monocarbure d'uranium prepare dans des conditions analogues, les produits obtenus ici, soumis a un traitement thermique, n'evoluent pas facilement vers un etat d'equilibre physico-chimique caracterise par l'existence de joints de grains rectilignes. On attribue ce phenomene a l'insolubilite de l'impurete UO{sub 2} dans UN. La densite, la durete, la conductibilite thermique de ces produits se revelent superieures a celles des nitrures d'uranium ou des cermets U-UN obtenus par les autres methodes. (auteur)

Possible uranium sources of Streltsovsky uranium ore field

International Nuclear Information System (INIS)

Zhang Lisheng

2005-01-01

The uranium deposit of the Late Jurassic Streltsovaky caldera in Transbaikalia of Russia is the largest uranium field associated with volcanics in the world, its uranium reserves are 280 000 t U, and it is the largest uranium resources in Russia. About one third of the caldera stratigraphic pile consists of strongly-altered rhyolites. Uranium resources of the Streltsovsky caldera are much larger than any other volcanic-related uranium districts in the world. Besides, the efficiency of hydrothermal alteration, uranium resources appear to result from the juxtaposition of two major uranium sources; highly fractionated peralkaline rhyolites of Jurassic age in the caldera, and U-rich subalkaline granites of Variscan age in the basement in which the major uranium-bearing accessory minerals were metamict at the time of the hydrothermal ore formation. (authors)

Competitive biosorption of thorium and uranium by actinomycetes

International Nuclear Information System (INIS)

Nakajima, Akira; Tsuruta, Takehiko

2002-01-01

The competitive biosorption of thorium and uranium by actinomycetes was examined. Of the actinomycetes tested, Streptomyces levoris showed the highest ability to sorb both thorium and uranium from aqueous systems. Thorium sorption was not affected by co-existed uranium, while uranium sorption was strongly hindered by co-existed thorium. The amounts of both thorium and uranium sorbed by Streptomyces levoris cells increased with an increase of the solution pH. Although the equilibrium isotherm of uranium biosorption is in similar manner as that of thorium biosorption, uranium was sorbed much faster than thorium. Biosorption isotherm of each metal ion could be well fitted by Langmuir isotherm taking the ionic charge of metal ions into account. The Langmuir isotherm for binary system did not explain completely the competitive biosorption of thorium and uranium by Streptomyces levoris. However, the results suggested that the ion species of both metals in the cells should be Th(OH) 2 2+ and UO 2 2+ , respectively. (author)

Short and long term ionizing radiation effects on charge-coupled devices in radiation environment of high-intensity heavy ion accelerators

International Nuclear Information System (INIS)

Belousov, A; Mustafin, E; Ensinger, W

2012-01-01

Radiation effects on semiconductor devices is a topical issue for high-intensity accelerator projects. In particular it concerns Charge-Coupled Device (CCD) cameras, which are widely used for beam profile monitoring and surveillance in high radiation environment. One should have a clear idea of short and long term radiation effects on such devices. To study these effects, a CCD camera was placed in positions less than half meter away from beam loss point. Primary heavy ion beam of 0.95GeV/n Uranium was dumped into a thick aluminium target creating high fluences of secondary particles (e.g., gammas, neutrons, protons). Effects of these particles on CCD camera were scored with LabView based acquisition software. Monte Carlo calculations with FLUKA code were performed to obtain fluence distributions for different particles and make relevant comparisons. Long term total ionising dose effects are represented by dark current increase, which was scored throughout experiment. Instant radiation effects are represented by creation of charge in CCD cells by ionising particles. Relation of this charge to beam intensity was obtained for different camera positions and fluences within 5 orders of magnitude ranges. With high intensities this charge is so high that it may dramatically influence data obtained from CCD camera used in high radiation environment. The linearity of described above relation confirms linear response of CCD to ionizing radiation. It gives an opportunity to find a new application to CCD cameras as beam loss monitors (BLM).

Fabrication procedures for manufacturing high uranium concentration dispersion fuel elements

International Nuclear Information System (INIS)

Souza, J.A.B.; Durazzo, M.

2010-01-01

IPEN developed and made available for routine production the technology for manufacturing dispersion type fuel elements for use in research reactors. However, the fuel produced at IPEN is limited to the uranium concentration of 3.0 gU/cm 3 by using the U 3 Si 2 -Al dispersion. Increasing the uranium concentration of the fuel is interesting by the possibility of increasing the reactor core reactivity and lifetime of the fuel. It is possible to increase the concentration of uranium in the fuel up to the technological limit of 4.8 gU/cm 3 for the U 3 Si 2 -Al dispersion, which is well placed around the world. This new fuel will be applicable in the new Brazilian-Multipurpose Reactor RMB. This study aimed to develop the manufacturing process of high uranium concentration fuel, redefining the procedures currently used in the manufacture of IPEN. This paper describes the main procedures adjustments that will be necessary. (author)

Fabrication procedures for manufacturing high uranium concentration dispersion fuel elements

Energy Technology Data Exchange (ETDEWEB)

Souza, Jose Antonio Batista de; Durazzo, Michelangelo, E-mail: jasouza@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

2011-07-01

IPEN developed and made available for routine production the technology for manufacturing dispersion type fuel elements for use in research reactors. However, the fuel produced at IPEN is limited to the uranium concentration of 3.0 g U/c m3 by using the U{sub 3}Si{sub 2}-Al dispersion. Increasing the uranium concentration of the fuel is interesting by the possibility of increasing the reactor core reactivity and lifetime of the fuel. It is possible to increase the concentration of uranium in the fuel up to the technological limit of 4.8 g U/c m3 for the U{sub 3}Si{sub 2}-Al dispersion, which is well placed around the world. This new fuel will be applicable in the new Brazilian- Multipurpose Reactor RMB. This study aimed to develop the manufacturing process of high uranium concentration fuel, redefining the procedures currently used in the manufacture of IPEN. This paper describes the main procedures adjustments that will be necessary. (author)

A new approach for the high-precision determination of the elemental uranium concentration in uranium ore by gamma-ray spectrometry

International Nuclear Information System (INIS)

Nagel, W.; Quik, F.

1993-01-01

A new approach for the determination of elemental uranium in uranium bearing ore, using high resolution gamma-ray spectrometry, was applied. Using a variant of the enrichment meter technique an agreement of better than 1% has been obtained between gamma-ray measurement results and the certified value obtained by other analytical methods. For the calibration of the gamma-ray spectrometer uranium reference samples have been used which are made available jointly in Europe and the USA as Certified Reference Materials for Gamma-ray Spectrometry (EC NRM 171 and NBS SRM 969, respectively). The measured ore has been put in a special designed container which ensured in all directions seen from the radiation window a uniform degree of infinite thickness of about 95%. The measurement results can be taken as an example for the applicability of gamma-ray spectrometry when high accuracy is required and under conditions where homogeneous distributed elemental uranium is embedded in a larger amount of matrix material. (author). 8 refs., 10 figs., 2 tabs., 2 appendices

A Highly Expressed High-Molecular-Weight S-Layer Complex of Pelosinus sp. Strain UFO1 Binds Uranium

Energy Technology Data Exchange (ETDEWEB)

Thorgersen, Michael P. [Univ. of Georgia, Athens, GA (United States). Dept. of Biochemistry and Molecular Biology; Lancaster, W. Andrew [Univ. of Georgia, Athens, GA (United States). Dept. of Biochemistry and Molecular Biology; Rajeev, Lara [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Biological Systems and Engineering Division; Ge, Xiaoxuan [Univ. of Georgia, Athens, GA (United States). Dept. of Biochemistry and Molecular Biology; Vaccaro, Brian J. [Univ. of Georgia, Athens, GA (United States). Dept. of Biochemistry and Molecular Biology; Poole, Farris L. [Univ. of Georgia, Athens, GA (United States). Dept. of Biochemistry and Molecular Biology; Arkin, Adam P. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Biological Systems and Engineering Division; Mukhopadhyay, Aindrila [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Biological Systems and Engineering Division; Adams, Michael W. W. [Univ. of Georgia, Athens, GA (United States). Dept. of Biochemistry and Molecular Biology

2016-12-02

Cell suspensions of Pelosinus sp. strain UFO1 were previously shown, using spectroscopic analysis, to sequester uranium as U(IV) complexed with carboxyl and phosphoryl group ligands on proteins. The goal of our present study was to characterize the proteins involved in uranium binding. Virtually all of the uranium in UFO1 cells was associated with a heterodimeric protein, which was termed the uranium-binding complex (UBC). The UBC was composed of two S-layer domain proteins encoded by UFO1_4202 and UFO1_4203. Samples of UBC purified from the membrane fraction contained 3.3 U atoms/heterodimer, but significant amounts of phosphate were not detected. The UBC had an estimated molecular mass by gel filtration chromatography of 15 MDa, and it was proposed to contain 150 heterodimers (UFO1_4203 and UFO1_4202) and about 500 uranium atoms. The UBC was also the dominant extracellular protein, but when purified from the growth medium, it contained only 0.3 U atoms/heterodimer. The two genes encoding the UBC were among the most highly expressed genes within the UFO1 genome, and their expressions were unchanged by the presence or absence of uranium. Therefore, the UBC appears to be constitutively expressed and is the first line of defense against uranium, including by secretion into the extracellular medium. Although S-layer proteins were previously shown to bind U(VI), here we showed that U(IV) binds to S-layer proteins, we identified the proteins involved, and we quantitated the amount of uranium bound. Widespread uranium contamination from industrial sources poses hazards to human health and to the environment. Here in this paper, we identified a highly abundant uranium-binding complex (UBC) from Pelosinus sp. strain UFO1. The complex makes up the primary protein component of the S-layer of strain UFO1 and binds 3.3 atoms of U(IV) per heterodimer. Finally, while other bacteria have been shown to bind U(VI) on their S-layer, we demonstrate here an example of U(IV) bound by

High-Uranium-Loaded U3O8-Al fuel element development program. Part 1

International Nuclear Information System (INIS)

Martin, M.M.

1993-01-01

The High-Uranium-Loaded U 3 O 8 -Al Fuel Element Development Program supports Argonne National Laboratory efforts to develop high-uranium-density research and test reactor fuel to accommodate use of low-uranium enrichment. The goal is to fuel most research and test reactors with uranium of less than 20% enrichment for the purpose of lowering the potential for diversion of highly-enriched material for nonpeaceful usages. The specific objective of the program is to develop the technological and engineering data base for U 3 O 8 -Al plate-type fuel elements of maximal uranium content to the point of vendor qualification for full scale fabrication on a production basis. A program and management plan that details the organization, supporting objectives, schedule, and budget is in place and preparation for fuel and irradiation studies is under way. The current programming envisions a program of about four years duration for an estimated cost of about two million dollars. During the decades of the fifties and sixties, developments at Oak Ridge National Laboratory led to the use of U 3 O 8 -Al plate-type fuel elements in the High Flux Isotope Reactor, Oak Ridge Research Reactor, Puerto Rico Nuclear Center Reactor, and the High Flux Beam Reactor. Most of the developmental information however applies only up to a uranium concentration of about 55 wt % (about 35 vol % U 3 O 8 ). The technical issues that must be addressed to further increase the uranium loading beyond 55 wt % U involve plate fabrication phenomena of voids and dogboning, fuel behavior under long irradiation, and potential for the thermite reaction between U 3 O 8 and aluminum

AC measurements on uranium doped high temperature superconductors

International Nuclear Information System (INIS)

Eisterer, M.

1999-11-01

The subject of this thesis is the influence of fission tracks on the superconducting properties of melt textured Y-123. The critical current densities, the irreversibility lines and the transition temperature were determined by means of ac measurements. The corresponding ac techniques are explored in detail. Deviations of the ac signal from the expectations according to the Bean model were explained by the dependence of the shielding currents on the electric field. This explanation is supported by the influence of the ac amplitude and frequency on the critical current density but also by a comparison of the obtained data with other experimental techniques. Y-123 has to be doped with uranium in order to induce fission tracks. Uranium forms normal conducting clusters, which are nearly spherical, with a diameter of about 300 nm. Fission of uranium-235 by thermal neutrons creates two high energy ions with a total energy of about 160 MeV. Each of these fission products induces a linear defect with a diameter of about 10 nm. The length of one fission track is 2-4 μm. At 77 K the critical current density is enhanced by the pinning action of the uranium clusters, compared to undoped samples. With decreasing temperature this influence becomes negligible. The critical current densities are strongly enhanced due to the irradiation. At low magnetic fields we find extremely high values for melt textured materials, e.g. 2.5x10 9 Am -2 at 77 K and 0.25 T or 6x10 10 Am -2 at 5 K. Since the critical current was found to be inverse proportional to the square root of the applied magnetic field it decreases rapidly as the field increases. This behavior is predicted by simple theoretical considerations, but is only valid at low temperatures as well as in low magnetic fields at high temperatures. At high fields the critical current drops more rapidly. The irreversibility lines are only slightly changed by this irradiation technique. Only a small shift to higher fields and temperatures

Study of uranium dioxyde sputtering induced by multicharged heavy ions at low and very low kinetic energy: projectile charge effect; Etude de la pulverisation du dioxyde d'uranium induite par des ions lourds multicharges de basse et tres basse energie cinetique; effet de la charge du projectile

Energy Technology Data Exchange (ETDEWEB)

Haranger, F

2003-12-01

Ion beam irradiation of a solid can lead to the emission of neutral or ionized atoms, molecules or clusters from the surface. This comes as a result of the atomic motion in the vicinity of the surface, induced by the transfer of the projectile energy. Then, the study of the sputtering process appears as a means to get a better understanding of the excited matter state around the projectile trajectory. In the case of slow multicharged ions, a strong electronic excitation can be achieved by the projectile neutralization above the solid surface and / or its deexcitation below the surface. Parallel to this, the slowing down of such ions is essentially related to elastic collision with the target atoms. The study of the effect of the initial charge state of slow multicharged ions, in the sputtering process, has been carried out by measuring the absolute angular distributions of emission of uranium atoms from a uranium dioxide surface. The experiments have been performed in two steps. First, the emitted particles are collected onto a substrate during irradiation. Secondly, the surface of the collectors is analyzed by Rutherford Backscattering Spectrometry (RBS). This method allows the characterization of the emission of neutrals, which are the vast majority of the sputtered particles. The results obtained provide an access to the evolution of the sputtering process as a function of xenon projectile ions charge state. The measurements have been performed over a wide kinetic energy range, from 81 down to 1.5 keV. This allowed a clear separation of the contribution of the kinetic energy and initial projectile charge state to the sputtering phenomenon. (author)

Coordination phenomena of cationic uranium(iv) complexes

International Nuclear Information System (INIS)

Rohwer, H.E.

1974-12-01

The coordination properties of the cationic uranium(IV) complexes UCl 3 + , UCl 2 2+ , UCl 3+ , and U 4+ were studied in a non-aqueous medium in the presence of perchlorate as counterion which, however, proved to coordinate to a much greater extent than expected. The strong neutral ligand, HMPA, could successively displace some of the perchlorates. An electrostatic model for the U(CIO 4 ) 4 -HMPA-acetone system compared favourably with the actual results. This emphasized the high ionic content in the bonding with actenoid cations, even with such a high charge as +4 . These conclusions are in agreement with studies 75 in which nitrate acts as counter ion. Correspondingly the uranium (IV) chemistry is characterized by the absence of typical 3d-organometallic chemistry, for example, strong bonding with CO, P(Phi) 3 etc, which strongly depends on covalent bonding. This stresses the fact that the d and f orbitals are not readily available for strong bond formation with the actenoids. 76

Highly charged ion trapping and cooling

International Nuclear Information System (INIS)

Beck, B. R.; Church, D. A.; Gruber, L.; Holder, J. P.; Schneider, D.; Steiger, J.

1998-01-01

In the past few years a cryogenic Penning trap (RETRAP) has been operational at the Electron Beam Ion Trap (EBIT) facility at Lawrence Livermore National Laboratory. The combination of RETRAP and EBIT provides a unique possibility of producing and re-trapping highly charged ions and cooling them to very low temperatures. Due to the high Coulomb potentials in such an ensemble of cold highly charged ions the Coulomb coupling parameter (the ratio of Coulomb potential to the thermal energy) can easily reach values of 172 and more. To study such systems is not only of interest in astrophysics to simulate White Dwarf star interiors but opens up new possibilities in a variety of areas (e.g. laser spectroscopy), cold highly charged ion beams

Uranium recovery in Sweden. History and perspective

International Nuclear Information System (INIS)

Hultgren, Aa.; Olsson, G.

1993-08-01

In 1945 the potential of nuclear energy for military and peaceful purpose had initiated a strong interest in Sweden to establish a national programme in the field. The Atomic Energy Committee was formed at the end of 1945 and charged the Research Institute of National Defence in January 1946 with the test to investigate possibilities of uranium recovery in Sweden. AB Atomenergi, a semi-state owned body, was formed in November 1947 to take charge of nuclear energy related research and development. The search for and the recovery of uranium from indigenous resources became a dominant objective over the first years of the company. The report gives a broad overview of the efforts to establish a national uranium fuel supply programme in Sweden from the early days of the postwar years of the 1940s. Process and plant development, plant operations at Kvarntorp and Ranstad, and the development of the uranium supply policy are presented against a background of the nuclear power development in the country. The nuclear weapons debate and the decision to sign the non proliferation treaty in 1968 are briefly reported. Special attention has been given an account of the technical development and the various projects related to the Ranstad plant and its final restoration in the 1980s

Candidate processes for diluting the 235U isotope in weapons-capable highly enriched uranium

International Nuclear Information System (INIS)

Snider, J.D.

1996-02-01

The United States Department of Energy (DOE) is evaluating options for rendering its surplus inventories of highly enriched uranium (HEU) incapable of being used to produce nuclear weapons. Weapons-capable HEU was earlier produced by enriching uranium in the fissile 235 U isotope from its natural occurring 0.71 percent isotopic concentration to at least 20 percent isotopic concentration. Now, by diluting its concentration of the fissile 235 U isotope in a uranium blending process, the weapons capability of HEU can be eliminated in a manner that is reversible only through isotope enrichment, and therefore, highly resistant to proliferation. To the extent that can be economically and technically justified, the down-blended uranium product will be made suitable for use as commercial reactor fuel. Such down-blended uranium product can also be disposed of as waste if chemical or isotopic impurities preclude its use as reactor fuel

Biomineral processing of high apatite containing low-grade indian uranium ore

International Nuclear Information System (INIS)

Abhilash; Mehta, K.D.; Pandey, B.D.; Ray, L.; Tamrakar, P.K.

2010-01-01

Microbial species isolated from source mine water, primarily an enriched culture of Acidithiobacillus ferrooxidans was employed for bio-leaching of uranium from a low-grade apatite rich uranium ore of Narwapahar Mines, India while varying pH, pulp density (PD), particle size, etc. The ore (0.047% U_3O_8), though of Singhbhum area (richest deposit of uranium ores in India), due to presence of some refractory minerals and high apatite (5%) causes a maximum 78% recovery through conventional processing. Bioleaching experiments were carried out by varying pH at 35"oC using 20%(w/v) PD and <76μm size particles resulting in 83.5% and 78% uranium bio-recovery at 1.7 and 2.0 pH in 40 days as against maximum recovery of 46% and 41% metal in control experiments respectively. Finer size (<45μm) ore fractions exhibited higher uranium dissolution (96%) in 40 days at 10% (w/v) pulp density (PD), 1.7 pH and 35"oC. On increasing the pulp density from 10% to 20% under the same conditions, the biorecovery of uranium fell down from 96% to 82%. The higher uranium dissolution during bioleaching at 1.7 pH with the fine size particles (<45μm) can be correlated with increase in redox potential from 598 mV to 708 mV and the corresponding variation of Fe(III) ion concentration in 40 days. (author)

Biomineral processing of high apatite containing low-grade indian uranium ore

Energy Technology Data Exchange (ETDEWEB)

Abhilash; Mehta, K.D.; Pandey, B.D., E-mail: biometnml@gmail.com [National Metallurgical Laboratory (CSIR), Jamshedpur (India); Ray, L. [Jadavpur Univ., FTBE Dept., Kolkata (India); Tamrakar, P.K. [Uranium Corp. of India Limited, CR& D Dept., Jaduguda (India)

2010-07-01

Microbial species isolated from source mine water, primarily an enriched culture of Acidithiobacillus ferrooxidans was employed for bio-leaching of uranium from a low-grade apatite rich uranium ore of Narwapahar Mines, India while varying pH, pulp density (PD), particle size, etc. The ore (0.047% U{sub 3}O{sub 8}), though of Singhbhum area (richest deposit of uranium ores in India), due to presence of some refractory minerals and high apatite (5%) causes a maximum 78% recovery through conventional processing. Bioleaching experiments were carried out by varying pH at 35{sup o}C using 20%(w/v) PD and <76μm size particles resulting in 83.5% and 78% uranium bio-recovery at 1.7 and 2.0 pH in 40 days as against maximum recovery of 46% and 41% metal in control experiments respectively. Finer size (<45μm) ore fractions exhibited higher uranium dissolution (96%) in 40 days at 10% (w/v) pulp density (PD), 1.7 pH and 35{sup o}C. On increasing the pulp density from 10% to 20% under the same conditions, the biorecovery of uranium fell down from 96% to 82%. The higher uranium dissolution during bioleaching at 1.7 pH with the fine size particles (<45μm) can be correlated with increase in redox potential from 598 mV to 708 mV and the corresponding variation of Fe(III) ion concentration in 40 days. (author)

Provision by the uranium and uranium products

International Nuclear Information System (INIS)

Elagin, Yu.P.

2005-01-01

International uranium market is converted from the buyer market into the seller market. The prices of uranium are high and the market attempts to adapt to changing circumstances. The industry of uranium enrichment satisfies the increasing demands but should to increase ots capacities. On the whole the situation is not stable and every year may change the existing position [ru

Uranium conversion

International Nuclear Information System (INIS)

Oliver, Lena; Peterson, Jenny; Wilhelmsen, Katarina

2006-03-01

FOI, has performed a study on uranium conversion processes that are of importance in the production of different uranium compounds in the nuclear industry. The same conversion processes are of interest both when production of nuclear fuel and production of fissile material for nuclear weapons are considered. Countries that have nuclear weapons ambitions, with the intention to produce highly enriched uranium for weapons purposes, need some degree of uranium conversion capability depending on the uranium feed material available. This report describes the processes that are needed from uranium mining and milling to the different conversion processes for converting uranium ore concentrate to uranium hexafluoride. Uranium hexafluoride is the uranium compound used in most enrichment facilities. The processes needed to produce uranium dioxide for use in nuclear fuel and the processes needed to convert different uranium compounds to uranium metal - the form of uranium that is used in a nuclear weapon - are also presented. The production of uranium ore concentrate from uranium ore is included since uranium ore concentrate is the feed material required for a uranium conversion facility. Both the chemistry and principles or the different uranium conversion processes and the equipment needed in the processes are described. Since most of the equipment that is used in a uranium conversion facility is similar to that used in conventional chemical industry, it is difficult to determine if certain equipment is considered for uranium conversion or not. However, the chemical conversion processes where UF 6 and UF 4 are present require equipment that is made of corrosion resistant material

Synthesis of Uranium nitride powders using metal uranium powders

International Nuclear Information System (INIS)

Yang, Jae Ho; Kim, Dong Joo; Oh, Jang Soo; Rhee, Young Woo; Kim, Jong Hun; Kim, Keon Sik

2012-01-01

Uranium nitride (UN) is a potential fuel material for advanced nuclear reactors because of their high fuel density, high thermal conductivity, high melting temperature, and considerable breeding capability in LWRs. Uranium nitride powders can be fabricated by a carbothermic reduction of the oxide powders, or the nitriding of metal uranium. The carbothermic reduction has an advantage in the production of fine powders. However it has many drawbacks such as an inevitable engagement of impurities, process burden, and difficulties in reusing of expensive N 15 gas. Manufacturing concerns issued in the carbothermic reduction process can be solved by changing the starting materials from oxide powder to metals. However, in nitriding process of metal, it is difficult to obtain fine nitride powders because metal uranium is usually fabricated in the form of bulk ingots. In this study, a simple reaction method was tested to fabricate uranium nitride powders directly from uranium metal powders. We fabricated uranium metal spherical powder and flake using a centrifugal atomization method. The nitride powders were obtained by thermal treating those metal particles under nitrogen containing gas. We investigated the phase and morphology evolutions of powders during the nitriding process. A phase analysis of nitride powders was also a part of the present work

Uranium rich granite and uranium productive granite in south China

Energy Technology Data Exchange (ETDEWEB)

Mingyue, Feng; Debao, He [CNNC Key Laboratory of Uranium Resource Exploration and Evaluation Technology, Beijing Research Institute of Uranium Geology (China)

2012-07-15

The paper briefly introduces the differences between uranium rich granite and uranium productive granite in the 5 provinces of South China, and discusses their main characteristics in 4 aspects, the uranium productive granite is highly developed in fracture, very strong in alteration, often occurred as two-mica granite and regularly developed with intermediate-basic and acid dikes. The above characteristics distinguish the uranium productive granite from the uranium rich granite. (authors)

Uranium rich granite and uranium productive granite in south China

International Nuclear Information System (INIS)

Feng Mingyue; He Debao

2012-01-01

The paper briefly introduces the differences between uranium rich granite and uranium productive granite in the 5 provinces of South China, and discusses their main characteristics in 4 aspects, the uranium productive granite is highly developed in fracture, very strong in alteration, often occurred as two-mica granite and regularly developed with intermediate-basic and acid dikes. The above characteristics distinguish the uranium productive granite from the uranium rich granite. (authors)

Reduction of uranium hexafluoride to uranium tetrafluoride

International Nuclear Information System (INIS)

Chang, I.S.; Do, J.B.; Choi, Y.D.; Park, M.H.; Yun, H.H.; Kim, E.H.; Kim, Y.W.

1982-01-01

The single step continuous reduction of uranium hexafluoride (UF 6 ) to uranium tetrafluoride (UF 4 ) has been investigated. Heat required to initiate and maintain the reaction in the reactor is supplied by the highly exothermic reaction of hydrogen with a small amount of elemental fluorine which is added to the uranium hexafluoride stream. When gases uranium hexafluoride and hydrogen react in a vertical monel pipe reactor, the green product, UF 4 has 2.5g/cc in bulk density and is partly contaminated by incomplete reduction products (UF 5 ,U 2 F 9 ) and the corrosion product, presumably, of monel pipe of the reactor itself, but its assay (93% of UF 4 ) is acceptable for the preparation of uranium metal with magnesium metal. Remaining problems are the handling of uranium hexafluoride, which is easily clogging the flowmeter and gas feeding lines because of extreme sensitivity toward moisture, and a development of gas nozzel for free flow of uranium hexafluoride gas. (Author)

Disposition of surplus highly enriched uranium: Draft environmental impact statement

International Nuclear Information System (INIS)

1995-10-01

This document assesses the environmental impacts at four potential sites that may result from alternatives for the disposition of United States-origin weapons-usable highly enriched uranium (HEU) that has been or may be declared surplus to national defense or defense-related program needs. In addition to the no action alternative, it assesses four alternatives that would eliminate the weapons-usability of HEU by blending it with depleted uranium, natural uranium, or low-enriched uranium (LEU) to create low-enriched uranium, either as commercial reactor fuel feedstock or as low-level radioactive waste. The potential blending sites are DOE's Y-12 Plant at Oak Ridge Reservation in Oak Ridge, Tennessee; DOE's Savannah River Site in Aiken, South Carolina; the Babcock ampersand Wilcox Naval Nuclear Fuel Division Facility in Lynchburg, Virginia; and the Nuclear Fuel Services Fuel Fabrication Plant in Erwin, Tennessee. Evaluations of impacts on site infrastructure, water resources, air quality and noise, socioeconomic resources, waste management, public and occupational health, and environmental justice for the potential blending sites are included in the assessment. The intersite transportation of nuclear and hazardous materials is also assessed. The preferred alternative is to blend down surplus HEU to LEU for maximum commercial use as reactor fuel feed which would likely be done at a combination of DOE and commercial sites

Results of EDS uranium samples characterization after hydrogen loading

International Nuclear Information System (INIS)

Chicea, D.; Dash, J.

2003-01-01

Several experiments of loading natural uranium foils with hydrogen were done. Electrolysis was used for loading hydrogen into uranium, because it is the most efficient way for H loading. The composition of the surface and near surface of the samples was determined using an Oxford EDS spectrometer on a Scanning Electron Microscope, manufactured by ISI. Images were taken with several magnifications up to 3.4KX. Results reveal that when low current density was used, the surface patterns changed from granules on the surface having a typical size of 2-4 microns to pits under the surface having a typical size under one micron. When high current density was used the surface changed and presented deep fissures. The deep fissures are the result of the mechanical strain induced by the lattice expansion caused by hydrogen absorption. The surface composition was determined before and after hydrogen loading. Uranium, thorium platinum and carbon concentration were measured. Experiments suggest that the amount of thorium increases on the uranium sample with the total electric charge transported through electrolyte. Carbon concentration was found to decrease on the surface of the sample as the total electric charge transported through electrolyte increased. Platinum is used in electrolysis experiment as anode primarily because it does not dissolve in electrolyte and therefore it is not electro-deposited on the cathode surface. The results of the platinum concentration measurements on the surface of the samples we loaded with hydrogen reveal that the platinum concentration increased dramatically as the current density increased and that created platinum spots on the cathode surface. Work is in progress on the subject. (authors)

Chapter 6. Uranium extraction possibilities from natural uranium-bearing waters of complex salt composition. 6.2. Technology for uranium extraction from brine with a high content of ion-chlorine

International Nuclear Information System (INIS)

Khakimov, N.; Nazarov, Kh.M.; Mirsaidov, I.U.

2012-01-01

Present article is devoted to technology for uranium extraction from brine with a high content of ion-chlorine. The content of basic anions and cations in lake waters of Sasik-Kul deposit was defined. Results of X-ray spectral analysis of salt residual after water evaporation from Sasik-Kul lake was discussed. Investigations revealed that uranium extraction from brines containing ion-chlorine is possible. The developed basic process flow diagram of uranium extraction from Sasik-Kul Lake' brine consists of the following basic stages: evaporation, leaching, catching of formed gases (HCl), sorption, desorption, deposition, drying and tempering.

Chapter 6. Uranium extraction possibilities from natural uranium-bearing waters of complex salt composition. 6.2. Technology for uranium extraction from brine with a high content of ion-chlorine

International Nuclear Information System (INIS)

Khakimov, N.; Nazarov, Kh.M.; Mirsaidov, I.U.

2011-01-01

Present article is devoted to technology for uranium extraction from brine with a high content of ion-chlorine. The content of basic anions and cations in lake waters of Sasik-Kul deposit was defined. Results of X-ray spectral analysis of salt residual after water evaporation from Sasik-Kul lake was discussed. Investigations revealed that uranium extraction from brines containing ion-chlorine is possible. The developed basic process flow diagram of uranium extraction from Sasik-Kul Lake' brine consists of the following basic stages: evaporation, leaching, catching of formed gases (HCl), sorption, desorption, deposition, drying and tempering.

Uranium-thorium fuel cycle in a very high temperature hybrid system

International Nuclear Information System (INIS)

Hernandez, C.R.G.; Oliva, A.M.; Fajardo, L.G.; Garcia, J.A.R.; Curbelo, J.P.; Abadanes, A.

2011-01-01

Thorium is a potentially valuable energy source since it is about three to four times as abundant as Uranium. It is also a widely distributed natural resource readily accessible in many countries. Therefore, Thorium fuels can complement Uranium fuels and ensure long term sustainability of nuclear power. The main advantages of the use of a hybrid system formed by a Pebble Bed critical nuclear reactor and two Pebble Bed Accelerator Driven Systems (ADSs) using a Uranium-Thorium (U + Th) fuel cycle are shown in this paper. Once-through and two step U + Th fuel cycle was evaluated. With this goal, a preliminary conceptual design of a hybrid system formed by a Graphite Moderated Gas-Cooled Very High Temperature Reactor and two ADSs is proposed. The main parameters related to the neutronic behavior of the system in a deep burn scheme are optimized. The parameters that describe the nuclear fuel breeding and Minor Actinide stockpile are compared with those of a simple Uranium fuel cycle. (author)

Highly dispersive ion exchangers in the analytical chemistry of uranium, particularly regarding separation methods

International Nuclear Information System (INIS)

Schoening, R.

1975-01-01

The reaction of water-insoluble polyvinyl pyrrolidon with uranium VI was investigated and a determination method for uranium was worked out in which the polyvinyl pyrrolidon was used as specific exchanger. Good separations of uranium from numerous transition metal ions were achieved here. The application of this exchanger for a fast and simple elution and determination method was of particular importance. A possible sorption mechanism was suggested based on the capacity curve of uranium with polyvinyl pyrrolidon and nitrogen and chloride content at maximum load. The sorption occurs by coordination of the carbonyl oxygen of single pyrrolidon rings with the protons of the complex acides and uranium. This assumption is supported by IR investigations. The sorbability of other inorganic acids was also investigated and possible structures were formulated for the sorption mechanism. In addition to this, ion exchangers were prepared based on cellulose by converting cellulose powder with aziridine and tris-1-aziridinyl-phosphine oxide. A polyethylene imine cellulose of high capacity was obtained in the conversion of cellulose powder with aziridine. This exchanger absorbs cobalt III very strongly. The exchanger loaded with cobalt III was used to separate the uranium as cyanato complex. The exchanger obtained in converting chlorated cellulose with tris-1-aziridinyl phosphine oxide also absorbs uranium VI very strongly. Thus a separation method of high specifity and selectivity was developed. (orig.) [de

Solubility measurement of uranium in uranium-contaminated soils

International Nuclear Information System (INIS)

Lee, S.Y.; Elless, M.; Hoffman, F.

1993-08-01

A short-term equilibration study involving two uranium-contaminated soils at the Fernald site was conducted as part of the In Situ Remediation Integrated Program. The goal of this study is to predict the behavior of uranium during on-site remediation of these soils. Geochemical modeling was performed on the aqueous species dissolved from these soils following the equilibration study to predict the on-site uranium leaching and transport processes. The soluble levels of total uranium, calcium, magnesium, and carbonate increased continually for the first four weeks. After the first four weeks, these components either reached a steady-state equilibrium or continued linearity throughout the study. Aluminum, potassium, and iron, reached a steady-state concentration within three days. Silica levels approximated the predicted solubility of quartz throughout the study. A much higher level of dissolved uranium was observed in the soil contaminated from spillage of uranium-laden solvents and process effluents than in the soil contaminated from settling of airborne uranium particles ejected from the nearby incinerator. The high levels observed for soluble calcium, magnesium, and bicarbonate are probably the result of magnesium and/or calcium carbonate minerals dissolving in these soils. Geochemical modeling confirms that the uranyl-carbonate complexes are the most stable and dominant in these solutions. The use of carbonate minerals on these soils for erosion control and road construction activities contributes to the leaching of uranium from contaminated soil particles. Dissolved carbonates promote uranium solubility, forming highly mobile anionic species. Mobile uranium species are contaminating the groundwater underlying these soils. The development of a site-specific remediation technology is urgently needed for the FEMP site

Charged vortices in high-Tc superconductors

International Nuclear Information System (INIS)

Matsuda, Y.; Kumagai, K.

2002-01-01

It is well known that a vortex in type II superconductors traps a magnetic flux. Recently the possibility that a vortex can accumulate a finite electric charge as well has come to be realized. The sign and magnitude of the vortex charge not only is closely related to the microscopic electronic structure of the vortex, but also strongly affects the dynamical properties of the vortex. In this chapter we demonstrate that a vortex in high-T c superconductors (HTSC) indeed traps a finite electronic charge, using the high resolution measurements of the nuclear quadrupole frequencies. We then discuss the vortex Hall anomaly whose relation with the vortex charging effect has recently received considerable attention. We show that the sign of the trapped charge is opposite to the sign predicted by the conventional BCS theory and deviation of the magnitude of the charge from the theory is also significant. We also show that the electronic structure of underlying system is responsible for the Hall sign in the vortex state and again the Hall sign is opposite to the sign predicted by the BCS theory. It appears that these unexpected features observed in both electrostatics and dynamics of the vortex may be attributed to the novel electronic structure of the vortex in HTSC. (orig.)

Cellular localization of uranium in the renal proximal tubules during acute renal uranium toxicity.

Science.gov (United States)

Homma-Takeda, Shino; Kitahara, Keisuke; Suzuki, Kyoko; Blyth, Benjamin J; Suya, Noriyoshi; Konishi, Teruaki; Terada, Yasuko; Shimada, Yoshiya

2015-12-01

Renal toxicity is a hallmark of uranium exposure, with uranium accumulating specifically in the S3 segment of the proximal tubules causing tubular damage. As the distribution, concentration and dynamics of accumulated uranium at the cellular level is not well understood, here, we report on high-resolution quantitative in situ measurements by high-energy synchrotron radiation X-ray fluorescence analysis in renal sections from a rat model of uranium-induced acute renal toxicity. One day after subcutaneous administration of uranium acetate to male Wistar rats at a dose of 0.5 mg uranium kg(-1) body weight, uranium concentration in the S3 segment of the proximal tubules was 64.9 ± 18.2 µg g(-1) , sevenfold higher than the mean renal uranium concentration (9.7 ± 2.4 µg g(-1) ). Uranium distributed into the epithelium of the S3 segment of the proximal tubules and highly concentrated uranium (50-fold above mean renal concentration) in micro-regions was found near the nuclei. These uranium levels were maintained up to 8 days post-administration, despite more rapid reductions in mean renal concentration. Two weeks after uranium administration, damaged areas were filled with regenerating tubules and morphological signs of tissue recovery, but areas of high uranium concentration (100-fold above mean renal concentration) were still found in the epithelium of regenerating tubules. These data indicate that site-specific accumulation of uranium in micro-regions of the S3 segment of the proximal tubules and retention of uranium in concentrated areas during recovery are characteristics of uranium behavior in the kidney. Copyright © 2015 John Wiley & Sons, Ltd.

Recovery of uranium from crude uranium tetrafluoride

Energy Technology Data Exchange (ETDEWEB)

Ghosh, S K; Bellary, M P; Keni, V S [Chemical Engineering Division, Bhabha Atomic Research Centre, Mumbai (India)

1994-06-01

An innovative process has been developed for recovery of uranium from crude uranium tetrafluoride cake. The process is based on direct dissolution of uranium tetrafluoride in nitric acid in presence of aluminium hydroxide and use of solvent extraction for removal of fluorides and other bulk impurities to make uranium amenable for refining. It is a simple process requiring minimum process step and has advantage of lesser plant corrosion. This process can be applied for processing of uranium tetrafluoride generated from various sources like uranium by-product during thorium recovery from thorium concentrate, first stage product of uranium recovery from phosphoric acid by OPPA process and off grade uranium tetrafluoride material. The paper describes the details of the process developed and demonstrated on bench and pilot scale and its subsequent modification arising out of bulky solid waste generation. The modified process uses a lower quantity of aluminium hydroxide by allowing a lower dissolution of uranium per cycle and recycles the undissolved material to the next cycle, maintaining the overall recovery at high level. This innovation has reduced the solid waste generated by a factor of four at the cost of a slightly larger dissolution vessel and its increased corrosion rate. (author). 4 refs., 1 fig., 3 tabs.

Recovery of uranium from crude uranium tetrafluoride

International Nuclear Information System (INIS)

Ghosh, S.K.; Bellary, M.P.; Keni, V.S.

1994-01-01

An innovative process has been developed for recovery of uranium from crude uranium tetrafluoride cake. The process is based on direct dissolution of uranium tetrafluoride in nitric acid in presence of aluminium hydroxide and use of solvent extraction for removal of fluorides and other bulk impurities to make uranium amenable for refining. It is a simple process requiring minimum process step and has advantage of lesser plant corrosion. This process can be applied for processing of uranium tetrafluoride generated from various sources like uranium by-product during thorium recovery from thorium concentrate, first stage product of uranium recovery from phosphoric acid by OPPA process and off grade uranium tetrafluoride material. The paper describes the details of the process developed and demonstrated on bench and pilot scale and its subsequent modification arising out of bulky solid waste generation. The modified process uses a lower quantity of aluminium hydroxide by allowing a lower dissolution of uranium per cycle and recycles the undissolved material to the next cycle, maintaining the overall recovery at high level. This innovation has reduced the solid waste generated by a factor of four at the cost of a slightly larger dissolution vessel and its increased corrosion rate. (author)

Transformations of highly enriched uranium into metal or oxide; Etudes des procedes de transformation des composes d'uranium a fort enrichissement isotopique

Energy Technology Data Exchange (ETDEWEB)

Nollet, P; Sarrat, P [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

1964-07-01

The enriched uranium workshops in Cadarache have a double purpose on the one hand to convert uranium hexafluoride into metal or oxide, and on the other hand to recover the uranium contained in scrap materials produced in the different metallurgical transformations. The principles that have been adopted for the design and safety of these workshops are reported. The nuclear safety is based on the geometrical limitations of the processing vessels. To establish the processes and the technology of these workshops, many studies have been made since 1960, some of which have led to original achievements. The uranium hexafluoride of high isotopic enrichment is converted either by injection of the gas into ammonia or by an original process of direct hydrogen reduction to uranium tetrafluoride. The uranium contained m uranium-zirconium metal scrap can be recovered by combustion with hydrogen chloride followed treatment of the uranium chloride by fluorine in order to obtain the uranium in the hexafluoride state. Recovery of the uranium contained m various scrap materials is obtained by a conventional refining process combustion of metallic scrap, nitric acid dissolution of the oxide, solvent purification by tributyl phosphate, ammonium diuranate precipitation, calcining, reduction and hydro fluorination into uranium tetrafluoride, bomb reduction by calcium and slag treatment. Two separate workshops operate along these lines one takes care of the uranium with an isotopic enrichment of up to 3 p. 100, the other handles the high enrichments. The handling of each step of this process, bearing in mind the necessity for nuclear safety, has raised some special technological problems and has led to the conception of new apparatus, in particular the roasting furnace for metal turnings, the nitric acid dissolution unit, the continuous precipitator and ever safe filter and dryer for ammonium diuranate, the reduction and hydro fluorination furnace and the slag recovery apparatus These are

Analytical method of uranium (IV) and uranium (VI) in uranium ores and uranium-bearing rocks

International Nuclear Information System (INIS)

Shen Zhuqin; Zheng Yongfeng; Li Qingzhen; Zhong Miaolan; Gu Dingxiang

1995-11-01

The best conditions for keeping the original valences of uranium during the dissolution and separation procedure of geological samples (especially those micro uranium-bearing rock) were studied. With the exist of high concentration protectants, the sample was decomposed with concentration HF at 40 +- 5 degree C. The U(VI) was dissolved completely and formed stable complex UO 2 F 2 , the U(IV) was precipitated rapidly and carried by carrier. Quantitative separation was carried out immediately with suction. The decomposition of sample and separation of solid/liquid phases was completed within two minutes. After separation, the U(IV) and U(VI) were determined quantitatively with laser fluorescence or voltametry respectively according to the uranium content. The limit of detection for this method is 0.7 μg/g, RSD is 10.5%, the determinate range of uranium is 2 x 10 -6 ∼10 -1 g/g. The uranium contents and their valence state ratio were measured for more than one hundred samples of sand stone and granite, the accuracy and precision of these results are satisfactory for uranium geological research. (12 tabs.; 11 refs.)

Production of High-Intensity, Highly Charged Ions

CERN Document Server

Gammino, S.

2013-12-16

In the past three decades, the development of nuclear physics facilities for fundamental and applied science purposes has required an increasing current of multicharged ion beams. Multiple ionization implies the formation of dense and energetic plasmas, which, in turn, requires specific plasma trapping configurations. Two types of ion source have been able to produce very high charge states in a reliable and reproducible way: electron beam ion sources (EBIS) and electron cyclotron resonance ion sources (ECRIS). Multiple ionization is also obtained in laser-generated plasmas (laser ion sources (LIS)), where the high-energy electrons and the extremely high electron density allow step-by-step ionization, but the reproducibility is poor. This chapter discusses the atomic physics background at the basis of the production of highly charged ions and describes the scientific and technological features of the most advanced ion sources. Particular attention is paid to ECRIS and the latest developments, since they now r...

Uranium industry framework

International Nuclear Information System (INIS)

Riley, K.

2008-01-01

The global uranium market is undergoing a major expansion due to an increase in global demand for uranium, the highest uranium prices in the last 20 years and recognition of the potential greenhouse benefits of nuclear power. Australia holds approximately 27% of the world's uranium resources (recoverable at under US$80/kg U), so is well placed to benefit from the expansion in the global uranium market. Increasing exploration activity due to these factors is resulting in the discovery and delineation of further high grade uranium deposits and extending Australia's strategic position as a reliable and safe supplier of low cost uranium.

Beta decay of highly charged ions

International Nuclear Information System (INIS)

Litvinov, Yuri A; Bosch, Fritz

2011-01-01

Beta decay of highly charged ions has attracted much attention in recent years. An obvious motivation for this research is that stellar nucleosynthesis proceeds at high temperatures where the involved atoms are highly ionized. Another important reason is addressing decays of well-defined quantum-mechanical systems, such as one-electron ions where all interactions with other electrons are excluded. The largest modifications of nuclear half-lives with respect to neutral atoms have been observed in beta decay of highly charged ions. These studies can be performed solely at ion storage rings and ion traps, because there high atomic charge states can be preserved for extended periods of time (up to several hours). Currently, all experimental results available in this field originate from experiments at the heavy-ion complex GSI in Darmstadt. There, the fragment separator facility FRS allows the production and separation of exotic, highly charged nuclides, which can then be stored and investigated in the storage ring facility ESR. In this review, we present and discuss in particular two-body beta decays, namely bound-state beta decay and orbital electron capture. Although we focus on experiments conducted at GSI, we will also attempt to provide general requirements common to any other experiment in this context. Finally, we address challenging but not yet performed experiments and we give prospects for the new radioactive beam facilities, such as FAIR in Darmstadt, IMP in Lanzhou and RIKEN in Wako.

High speed auto-charging system for condenser bank

International Nuclear Information System (INIS)

Mizuno, Yasunori; Bito, Fumio; Fujita, Kazuhiko; Sometani, Taro

1987-01-01

A current-control type high-speed charging system, which is intended for auto-charging of the condenser bank, is developed. Moreover, the system can also serve to compensate the current leakage from the condenser bank so that the charged voltage can be kept constant. The system consists of a sequence circuit, a charging current control circuit (or auto-charging circuit) and a charging circuit. The auto-charging circuit is characterized by the use of a triac to control the current. The current, controlled by the circuit, is supplied to the condenser bank through a step-up transformer and voltage doubler rectifier circuit. It is demonstrated that the use of the high-speed auto-charging circuit can largely decrease the required charging time, compared to constant voltage charging. In addition, the compensation function is shown to serve effectively for maintaining a constant voltage after the completion of charging. The required charging time is decreases as the charging current increases. The maximum charging current is decided by the rating of the traic and the current rating of the rectifier diode in the secondary circuit. Major components of these circuits have decreased impedances to minimize the effect of noise, so that the possibility of an accident can be eliminated. Other various improvements are made in the grounding circuit and the charging protection circuit in order to ensure safety. (Nogami, K.)

Design and synthesis of a water-stable anionic uranium-based metal-organic framework (MOF) with ultra large pores

Energy Technology Data Exchange (ETDEWEB)

Li, Peng; Vermeulen, Nicolaas A.; Gong, Xirui; Malliakas, Christos D.; Stoddart, J. Fraser; Hupp, Joseph T. [Northwestern Univ., Evanston, IL (United States). Dept. of Chemistry; Farha, Omar K. [Northwestern Univ., Evanston, IL (United States). Dept. of Chemistry; King Abdulaziz Univ., Jeddah (Saudi Arabia). Dept. of Chemistry

2016-08-22

Ionic metal-organic frameworks (MOFs) are a subclass of porous materials that have the ability to incorporate different charged species in confined nanospace by ion-exchange. To date, however, very few examples combining mesoporosity and water stability have been realized in ionic MOF chemistry. Herein, we report the rational design and synthesis of a water-stable anionic mesoporous MOF based on uranium and featuring tbo-type topology. The resulting tbo MOF exhibits exceptionally large open cavities (3.9 nm) exceeding those of all known anionic MOFs. By supercritical CO{sub 2} activation, a record-high Brunauer-Emmett-Teller (BET) surface area (2100 m{sup 2} g{sup -1}) for actinide-based MOFs has been obtained. Most importantly, however, this new uranium-based MOF is water-stable and able to absorb positively charged ions selectively over negatively charged ones, enabling the efficient separation of organic dyes and biomolecules.

Uranium production in thorium/denatured uranium fueled PWRs

International Nuclear Information System (INIS)

Arthur, W.B.

1977-01-01

Uranium-232 buildup in a thorium/denatured uranium fueled pressurized water reactor, PWR(Th), was studied using a modified version of the spectrum-dependent zero dimensional depletion code, LEOPARD. The generic Combustion Engineering System 80 reactor design was selected as the reactor model for the calculations. Reactors fueled with either enriched natural uranium and self-generated recycled uranium or uranium from a thorium breeder and self-generated recycled uranium were considered. For enriched natural uranium, concentrations of 232 U varied from about 135 ppM ( 232 U/U weight basis) in the zeroth generation to about 260 ppM ( 232 U/U weight basis) at the end of the fifth generation. For the case in which thorium breeder fuel (with its relatively high 232 U concentration) was used as reactor makeup fuel, concentrations of 232 U varied from 441 ppM ( 232 U/U weight basis) at discharge from the first generation to about 512 ppM ( 232 U/U weight basis) at the end of the fifth generation. Concentrations in freshly fabricated fuel for this later case were 20 to 35% higher than the discharge concentration. These concentrations are low when compared to those of other thorium fueled reactor types (HTGR and MSBR) because of the relatively high 238 U concentration added to the fuel as a denaturant. Excellent agreement was found between calculated and existing experimental values. Nevertheless, caution is urged in the use of these values because experimental results are very limited, and the relevant nuclear data, especially for 231 Pa and 232 U, are not of high quality

Nickel container of highly-enriched uranium bodies and sodium

Science.gov (United States)

Zinn, Walter H.

1976-01-01

A fuel element comprises highly a enriched uranium bodies coated with a nonfissionable, corrosion resistant material. A plurality of these bodies are disposed in layers, with sodium filling the interstices therebetween. The entire assembly is enclosed in a fluid-tight container of nickel.

Nickel container of highly-enriched uranium bodies and sodium

International Nuclear Information System (INIS)

Zinn, W.H.

1976-01-01

A fuel element comprises highly enriched uranium bodies coated with a nonfissionable, corrosion resistant material. A plurality of these bodies are disposed in layers, with sodium filling the interstices therebetween. The entire assembly is enclosed in a fluid-tight container of nickel

Experiments with highly charged ions up to bare U92+ on the electron beam ion trap

International Nuclear Information System (INIS)

Beiersdorfer, P.

1994-07-01

An overview is given of the current experimental effort to investigate the level structure of highly charged ions with the Livermore electron beam ion trap (EBIT) facility. The facility allows the production and study of virtually any ionization state of any element up to bare U 92+ . Precision spectroscopic measurements have been performed for a range of Δn = 0 and Δn = 1 transitions. Examples involving 3-4 and 2-3 as well as 3-3 and 2-2 transitions in uranium ions are discussed that illustrated some of the measurement and analysis techniques employed. The measurements have allowed tests of calculations of the the quantum electrodynamical contributions to the transitions energies at the 0.4% level in a regime where (Zα) ∼ 1

Enriched-uranium feed costs for the High-Temperature Gas-Cooled reactor: trends and comparison with other reactor concepts

International Nuclear Information System (INIS)

Thomas, W.E.

1976-04-01

This report discusses each of the components that affect the unit cost for enriched uranium; that is, ore costs, U 3 O 8 to UF 6 conversion cost, costs for enriching services, and changes in transaction tails assay. Historical trends and announced changes are included. Unit costs for highly enriched uranium (93.15 percent 235 U) and for low-enrichment uranium (3.0, 3.2, and 3.5 percent 235 U) are displayed as a function of changes in the above components and compared. It is demonstrated that the trends in these cost components will probably result in significantly less cost increase for highly enriched uranium than for low-enrichment uranium--hence favoring the High-Temperature Gas-Cooled Reactor

D. C. electric field behavior of high lying states in atomic uranium

International Nuclear Information System (INIS)

Paisner, J.A.; Carlson, L.R.; Worden, E.F.; Johnson, S.A.; May, C.A.; Solarz, R.W.

1976-01-01

The effects of D. C. electric fields on high lying Rydberg and valence states in atomic uranium have been studied. Results of measurements of Stark shifts, lifetime lengthening via l-mixing, critical fields for ionization, barrier tunneling, and the appearance of zero-field parity forbidden transitions are presented for atomic uranium along with the observation of field induced autoionization of valence states. 3 figs

Design of high density gamma-phase uranium alloys for LEU dispersion fuel applications

International Nuclear Information System (INIS)

Hofman, Gerard L.; Meyer, Mitchell K.; Ray, Allison E.

1998-01-01

Uranium alloys are candidates for the fuel phase in aluminium matrix dispersion fuels requiring high uranium loading. Certain uranium alloys have been shown to have good irradiation performance at intermediate burnup. previous studies have shown that acceptable fission gas swelling behavior and fuel-aluminium interaction is possible only if the fuel alloy can be maintained in the high temperature body-centered-cubic γ-phase during fabrication and irradiation, at temperatures at which αU is the equilibrium phase. transition metals in Groups V through VIII are known to allow metastable retention of the gamma phase below the equilibrium isotherm. These metals have varying degrees of effectiveness in stabilizing the gamma phase. Certain alloys are metastable for very long times at the relatively low fuel temperatures seen in research operation. In this paper, the existing data on the gamma stability of binary and ternary uranium alloys is analysed. The mechanism and kinetics of decomposition of the gamma phase are assessed with the help of metal alloy theory. Alloys with the highest possible uranium content, good gamma-phase stability, and good neutronic performance are identified for further metallurgical studies and irradiation tests. Results from theory will be compared with experimentally generated data. (author)

ECRIS sources for highly charged ions

International Nuclear Information System (INIS)

Geller, R.

1991-01-01

The so-called Philips ionization gauge ion sources (PIGIS) were used until quite recently in heavy ion accelerators so multiply charged ions could only be obtained by incorporating a stripper to remove electrons. Electron cyclotron resonance ion sources (ECRIS) now dominate as they produce more highly charged ions. (orig.)

Purification of uranium metal

International Nuclear Information System (INIS)

Suzuki, Kenji; Shikama, Tatsuo; Ochiai, Akira.

1993-01-01

We developed the system for purifying uranium metal and its metallic compounds and for growing highly pure uranium compounds to study their intrinsic physical properties. Uranium metal was zone refined under low contamination conditions as far as possible. The degree of the purity of uranium metal was examined by the conventional electrical resistivity measurement and by the chemical analysis using the inductive coupled plasma emission spectrometry (ICP). The results show that some metallic impurities evaporated by the r.f. heating and other usual metallic impurities moved to the end of a rod with a molten zone. Therefore, we conclude that the zone refining technique is much effective to the removal of metallic impurities and we obtained high purified uranium metal of 99.99% up with regarding to metallic impurities. The maximum residual resistivity ratio, the r.r.r., so far obtained was about 17-20. Using the purified uranium, we are attempting to grow a highly pure uranium-titanium single crystals. (author)

Supply of low enriched (LEU) and highly enriched uranium (HEU) for research reactors

International Nuclear Information System (INIS)

Mueller, H.

1997-01-01

Enriched uranium for research reactors in the form of LEU /= low enriched uranium at 19.75% U-235) and HEU (= highly enriched uranium at 90 to 93% U-235) was and is - due to its high U-235 enrichment - a political fuel other than enriched uranium for power reactors. The sufficient availability of LEU and HEU is a vital question for research reactors, especially in Europe, in order to perform their peaceful research reactor programs. In the past the USA were in the Western hemisphere sole supplier of LEU and HEU. Today the USA have de facto stopped the supply of LEU and HEU, for HEU mainly due to political reasons. This paper deals, among others, with the present availability of LEU and HEU for European research reactors and touches the following topics: - historical US supplies, - influence of the RERTR-program, - characteristics of LEU and HEU, - military HEU enters the civil market, -what is the supply situation for LEU and HEU today? - outlook for safe supplies of LEU and HEU. (author)

Uranium management activities

International Nuclear Information System (INIS)

Jackson, D.; Marshall, E.; Sideris, T.; Vasa-Sideris, S.

2001-01-01

One of the missions of the Department of Energy's (DOE) Oak Ridge Office (ORO) has been the management of the Department's uranium materials. This mission has been accomplished through successful integration of ORO's uranium activities with the rest of the DOE complex. Beginning in the 1980's, several of the facilities in that complex have been shut down and are in the decommissioning process. With the end of the Cold War, the shutdown of many other facilities is planned. As a result, inventories of uranium need to be removed from the Department facilities. These inventories include highly enriched uranium (HEU), low enriched uranium (LEU), normal uranium (NU), and depleted uranium (DU). The uranium materials exist in different chemical forms, including metals, oxides, solutions, and gases. Much of the uranium in these inventories is not needed to support national priorities and programs. (author)

Research reactor core conversion from the use of highly enriched uranium to the use of low enriched uranium fuels guidebook

International Nuclear Information System (INIS)

1980-08-01

In view of the proliferation concerns caused by the use of highly enriched uranium (HEU) and in anticipation that the supply of HEU to research and test reactors will be more restricted in the future, this document has been prepared to assist reactor operators in determining whether conversion to the use of low enriched uranium (LEU) fuel designs is technically feasible for their specific reactor, and to assist in making a smooth transition to the use of LEU fuel designs where appropriate

Multiple Coulomb scattering of high-energy heavy charged particle beams used in biology and medicine

International Nuclear Information System (INIS)

Wong, M.; Schimmerling, W.; Ludewigt, B.; Phillips, M.; Curtis, S.; Tobias, C.A.

1987-01-01

The authors measured lateral displacement and angular distributions of high-energy heavy charged particles emerging from a target at the Lawrence Berkeley Laboratory BEVALAC with beams used in radiobiology experiments. Multiple Coulomb scattering occurring in the target material generally spreads the beam laterally and increases its divergence. The apparatus consists of four sets of position-sensitive semiconductor detectors located along the beam line. Each providing two position signals and one energy signal. The difference between the two position signals is used to determine the particle position in one dimension. The two position signals are constrained to add up to the energy deposition signal in order to reject multiple-particle traversals. The vector directions for the incident and emerging particles are reconstructed in three dimensions from their measured coordinated positions. Lateral and angular distributions are reported for beams of high-energy neon, iron and uranium ions incident on targets of aluminum, cooper, lead and water

Irradiation Stability of Uranium Alloys at High Exposures

International Nuclear Information System (INIS)

McDonell, W.R.

2001-01-01

Postirradiation examinations were begun of a series of unrestrained dilute uranium alloy specimens irradiated to exposures up to 13,000 MWD/T in NaK-containing stainless steel capsules. This test, part of a program of development of uranium metal fuels for desalination and power reactors sponsored by the Division of Reactor Development and Technology, has the objective of defining the temperature and exposure limits of swelling resistance of the alloyed uranium. This paper discusses those test results

Atomic structure of highly-charged ions. Final report

International Nuclear Information System (INIS)

Livingston, A. Eugene

2002-01-01

Atomic properties of multiply charged ions have been investigated using excitation of energetic heavy ion beams. Spectroscopy of excited atomic transitions has been applied from the visible to the extreme ultraviolet wavelength regions to provide accurate atomic structure and transition rate data in selected highly ionized atoms. High-resolution position-sensitive photon detection has been introduced for measurements in the ultraviolet region. The detailed structures of Rydberg states in highly charged beryllium-like ions have been measured as a test of long-range electron-ion interactions. The measurements are supported by multiconfiguration Dirac-Fock calculations and by many-body perturbation theory. The high-angular-momentum Rydberg transitions may be used to establish reference wavelengths and improve the accuracy of ionization energies in highly charged systems. Precision wavelength measurements in highly charged few-electron ions have been performed to test the most accurate relativistic atomic structure calculations for prominent low-lying excited states. Lifetime measurements for allowed and forbidden transitions in highly charged few-electron ions have been made to test theoretical transition matrix elements for simple atomic systems. Precision lifetime measurements in laser-excited alkali atoms have been initiated to establish the accuracy of relativistic atomic many-body theory in many-electron systems

Study of the low temperature oxidation of uranium powders and its application to the sintering of uranium oxide powders; Etude de l'oxydation des poudres dtranium a basse temperature et son application au frittage de poudres d'uranium oxyde

Energy Technology Data Exchange (ETDEWEB)

Conte-Albert, M. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1964-06-01

The uranium oxygen reaction has been studied with a view to obtaining U-UO{sub 2} samples containing about 20 per cent by weight of UO{sub 2} starting from spherical grain uranium powder (36 {mu} < {phi} < 50 {mu}). The techniques used are micrography, thermogravimetry, sintering under pressure, radio-crystallography. At 170 deg. C in air or argon + oxygen mixtures, the uranium oxide formed is always UO{sub 2} and it is uniformly distributed around the initial uranium spheres. These mixed powders can easily be sintered under pressure in the {gamma}-phase. The density of the samples obtained is 85 to 90 per cent of the theoretical density. The influence of UO{sub 2} on the properties of uranium has been shown by the use of dilatometry and thermal cycling in the {alpha} phase. The temperatures at which the phase changes {alpha} {r_reversible} {beta} and {beta} {r_reversible} {gamma} occur are lowered, the remnant expansion is decreased. High density samples resist well to thermal cycling; the characteristic defects of uranium: high distortion, wrinkled surface, have almost disappeared. Heat treatments in a secondary vacuum at 1050 deg. C cause crystallization of UO{sub 2} in a geometrical form and the appearance of a phase of the F.C.C. crystalline type having the composition U{sub W}C{sub X}O{sub Y}N{sub Z}. This phase causes a new decrease in the {alpha} {r_reversible} {beta}, {beta} {r_reversible} {gamma} transformation temperatures for the uranium. After ten dilatometric cycles the remanent expansion of the sample is about 0.5 per cent. The resistance to thermal cycling of a low density sample which has been heat-treated is similar to that of a high density sample which has not undergone a heat treatment. (author) [French] La reaction uranium-oxygene a ete etudiee pour permettre l'obtention d'echantillons U-UO{sub 2} a 20 pour cent en poids environ d'UO{sub 2}, a partir de billes d'uranium pulverulent (36 {mu} < {phi} < 50 {mu}). Les

Uranium conversion; Urankonvertering

Energy Technology Data Exchange (ETDEWEB)

Oliver, Lena; Peterson, Jenny; Wilhelmsen, Katarina [Swedish Defence Research Agency (FOI), Stockholm (Sweden)

2006-03-15

FOI, has performed a study on uranium conversion processes that are of importance in the production of different uranium compounds in the nuclear industry. The same conversion processes are of interest both when production of nuclear fuel and production of fissile material for nuclear weapons are considered. Countries that have nuclear weapons ambitions, with the intention to produce highly enriched uranium for weapons purposes, need some degree of uranium conversion capability depending on the uranium feed material available. This report describes the processes that are needed from uranium mining and milling to the different conversion processes for converting uranium ore concentrate to uranium hexafluoride. Uranium hexafluoride is the uranium compound used in most enrichment facilities. The processes needed to produce uranium dioxide for use in nuclear fuel and the processes needed to convert different uranium compounds to uranium metal - the form of uranium that is used in a nuclear weapon - are also presented. The production of uranium ore concentrate from uranium ore is included since uranium ore concentrate is the feed material required for a uranium conversion facility. Both the chemistry and principles or the different uranium conversion processes and the equipment needed in the processes are described. Since most of the equipment that is used in a uranium conversion facility is similar to that used in conventional chemical industry, it is difficult to determine if certain equipment is considered for uranium conversion or not. However, the chemical conversion processes where UF{sub 6} and UF{sub 4} are present require equipment that is made of corrosion resistant material.

Design and synthesis of a water-stable anionic uranium-based metal-organic framework (MOF) with ultra large pores

Energy Technology Data Exchange (ETDEWEB)

Li, Peng; Vermeulen, Nicolaas A.; Gong, Xirui; Malliakas, Christos D.; Stoddart, J. Fraser; Hupp, Joseph T. [Department of Chemistry, Northwestern University, Evanston, IL (United States); Farha, Omar K. [Department of Chemistry, Northwestern University, Evanston, IL (United States); Department of Chemistry, Faculty of Science, King Abdulaziz University, Jeddah (Saudi Arabia)

2016-08-22

Ionic metal-organic frameworks (MOFs) are a subclass of porous materials that have the ability to incorporate different charged species in confined nanospace by ion-exchange. To date, however, very few examples combining mesoporosity and water stability have been realized in ionic MOF chemistry. Herein, we report the rational design and synthesis of a water-stable anionic mesoporous MOF based on uranium and featuring tbo-type topology. The resulting tbo MOF exhibits exceptionally large open cavities (3.9 nm) exceeding those of all known anionic MOFs. By supercritical CO{sub 2} activation, a record-high Brunauer-Emmett-Teller (BET) surface area (2100 m{sup 2} g{sup -1}) for actinide-based MOFs has been obtained. Most importantly, however, this new uranium-based MOF is water-stable and able to absorb positively charged ions selectively over negatively charged ones, enabling the efficient separation of organic dyes and biomolecules. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Charge collection and charge pulse formation in highly irradiated silicon planar detectors

International Nuclear Information System (INIS)

Dezillie, B.; Li, Z.; Eremin, V.

1998-06-01

The interpretation of experimental data and predictions for future experiments for high-energy physics have been based on conventional methods like capacitance versus voltage (C-V) measurements. Experiments carried out on highly irradiated detectors show that the kinetics of the charge collection and the dependence of the charge pulse amplitude on the applied bias are deviated too far from those predicted by the conventional methods. The described results show that in highly irradiated detectors, at a bias lower than the real full depletion voltage (V fd ), the kinetics of the charge collection (Q) contains a fast and a slow component. At V = V fd *, which is the full depletion voltage traditionally determined by the extrapolation of the fast component amplitude of q versus bias to the maximum value or from the standard C-V measurements, the pulse has a slow component with significant amplitude. This slow component can only be eliminated by applying additional bias that amounts to the real full depletion voltage (V fd ) or more. The above mentioned regularities are explained in this paper in terms of a model of an irradiated detector with multiple regions. This model allows one to use C-V, in a modified way, as well as TChT (transient charge technique) measurements to determine the V fd for highly irradiated detectors

Derived enriched uranium market

International Nuclear Information System (INIS)

Rutkowski, E.

1996-01-01

The potential impact on the uranium market of highly enriched uranium from nuclear weapons dismantling in the Russian Federation and the USA is analyzed. Uranium supply, conversion, and enrichment factors are outlined for each country; inventories are also listed. The enrichment component and conversion components are expected to cause little disruption to uranium markets. The uranium component of Russian derived enriched uranium hexafluoride is unresolved; US legislation places constraints on its introduction into the US market

Influence of uranium hydride oxidation on uranium metal behaviour

International Nuclear Information System (INIS)

Patel, N.; Hambley, D.; Clarke, S.A.; Simpson, K.

2013-01-01

This work addresses concerns that the rapid, exothermic oxidation of active uranium hydride in air could stimulate an exothermic reaction (burning) involving any adjacent uranium metal, so as to increase the potential hazard arising from a hydride reaction. The effect of the thermal reaction of active uranium hydride, especially in contact with uranium metal, does not increase in proportion with hydride mass, particularly when considering large quantities of hydride. Whether uranium metal continues to burn in the long term is a function of the uranium metal and its surroundings. The source of the initial heat input to the uranium, if sufficient to cause ignition, is not important. Sustained burning of uranium requires the rate of heat generation to be sufficient to offset the total rate of heat loss so as to maintain an elevated temperature. For dense uranium, this is very difficult to achieve in naturally occurring circumstances. Areas of the uranium surface can lose heat but not generate heat. Heat can be lost by conduction, through contact with other materials, and by convection and radiation, e.g. from areas where the uranium surface is covered with a layer of oxidised material, such as burned-out hydride or from fuel cladding. These rates of heat loss are highly significant in relation to the rate of heat generation by sustained oxidation of uranium in air. Finite volume modelling has been used to examine the behaviour of a magnesium-clad uranium metal fuel element within a bottle surrounded by other un-bottled fuel elements. In the event that the bottle is breached, suddenly, in air, it can be concluded that the bulk uranium metal oxidation reaction will not reach a self-sustaining level and the mass of uranium oxidised will likely to be small in relation to mass of uranium hydride oxidised. (authors)

Influence of uranium hydride oxidation on uranium metal behaviour

Energy Technology Data Exchange (ETDEWEB)

Patel, N.; Hambley, D. [National Nuclear Laboratory (United Kingdom); Clarke, S.A. [Sellafield Ltd (United Kingdom); Simpson, K.

2013-07-01

This work addresses concerns that the rapid, exothermic oxidation of active uranium hydride in air could stimulate an exothermic reaction (burning) involving any adjacent uranium metal, so as to increase the potential hazard arising from a hydride reaction. The effect of the thermal reaction of active uranium hydride, especially in contact with uranium metal, does not increase in proportion with hydride mass, particularly when considering large quantities of hydride. Whether uranium metal continues to burn in the long term is a function of the uranium metal and its surroundings. The source of the initial heat input to the uranium, if sufficient to cause ignition, is not important. Sustained burning of uranium requires the rate of heat generation to be sufficient to offset the total rate of heat loss so as to maintain an elevated temperature. For dense uranium, this is very difficult to achieve in naturally occurring circumstances. Areas of the uranium surface can lose heat but not generate heat. Heat can be lost by conduction, through contact with other materials, and by convection and radiation, e.g. from areas where the uranium surface is covered with a layer of oxidised material, such as burned-out hydride or from fuel cladding. These rates of heat loss are highly significant in relation to the rate of heat generation by sustained oxidation of uranium in air. Finite volume modelling has been used to examine the behaviour of a magnesium-clad uranium metal fuel element within a bottle surrounded by other un-bottled fuel elements. In the event that the bottle is breached, suddenly, in air, it can be concluded that the bulk uranium metal oxidation reaction will not reach a self-sustaining level and the mass of uranium oxidised will likely to be small in relation to mass of uranium hydride oxidised. (authors)

The Pajarito Monitor: a high-sensitivity monitoring system for highly enriched uranium

International Nuclear Information System (INIS)

Fehlau, P.E.; Coop, K.; Garcia, C.; Martinez, J.

1984-01-01

The Pajarito Monitor for Special Nuclear Material is a high-sensitivity gamma-ray monitoring system for detecting small quantities of highly enriched uranium transported by pedestrians or motor vehicles. The monitor consists of two components: a walk-through personnel monitor and a vehicle monitor. The personnel monitor has a plastic-scintillator detector portal, a microwave occupancy monitor, and a microprocessor control unit that measures the radiation intensity during background and monitoring periods to detect transient diversion signals. The vehicle monitor examines stationary motor vehicles while the vehicle's occupants pass through the personnel portal to exchange their badges. The vehicle monitor has four groups of large plastic scintillators that scan the vehicle from above and below. Its microprocessor control unit measures separate radiation intensities in each detector group. Vehicle occupancy is sensed by a highway traffic detection system. Each monitor's controller is responsible for detecting diversion as well as serving as a calibration and trouble-shooting aid. Diversion signals are detected by a sequential probability ratio hypothesis test that minimizes the monitoring time in the vehicle monitor and adapts itself well to variations in individual passage speed in the personnel monitor. Designed to be highly sensitive to diverted enriched uranium, the monitoring system also exhibits exceptional sensitivity for plutonium

A Very High Uranium Density Fission Mo Target Suitable for LEU Using atomization Technology

Energy Technology Data Exchange (ETDEWEB)

Kim, C. K.; Kim, K. H.; Lee, Y. S.; Ryu, H. J.; Woo, Y. M.; Jang, S. J.; Park, J. M.; Choi, S. J. [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2011-05-15

Currently HEU minimization efforts in fission Mo production are underway in connection with the global threat reduction policy. In order to convert HEU to LEU for the fission Mo target, higher uranium density material could be applied. The uranium aluminide targets used world widely for commercial {sup 99}Mo production are limited to 3.0 g-U/cc in uranium density of the target meat. A consideration of high uranium density using the uranium metal particles dispersion plate target is taken into account. The irradiation burnup of the fission Mo target are as low as 8 at.% and the irradiation period is shorter than 7 days. Pure uranium material has higher thermal conductivity than uranium compounds or alloys. It is considered that the degradation by irradiation would be almost negligible. In this study, using the computer code of the PLATE developed by ANL the irradiation behavior was estimated. Some considerations were taken into account to improve the irradiation performance further. It has been known that some alloying elements of Si, Cr, Fe, and Mo are beneficial for reducing the swelling by grain refinement. In the RERTR program recently the interaction problem could be solved by adding a small amount of Si to the aluminum matrix phase. The fabrication process and the separation process for the proposed atomized uranium particles dispersion target were reviewed

Application of response surface methodology to optimize uranium biological leaching at high pulp density

International Nuclear Information System (INIS)

Fatemi, Faezeh; Arabieh, Masoud; Jahani, Samaneh

2016-01-01

The aim of the present study was to carry out uranium bioleaching via optimization of the leaching process using response surface methodology. For this purpose, the native Acidithiobacillus sp. was adapted to different pulp densities following optimization process carried out at a high pulp density. Response surface methodology based on Box-Behnken design was used to optimize the uranium bioleaching. The effects of six key parameters on the bioleaching efficiency were investigated. The process was modeled with mathematical equation, including not only first and second order terms, but also with probable interaction effects between each pair of factors.The results showed that the extraction efficiency of uranium dropped from 100% at pulp densities of 2.5, 5, 7.5 and 10% to 68% at 12.5% of pulp density. Using RSM, the optimum conditions for uranium bioleaching (12.5% (w/v)) were identified as pH = 1.96, temperature = 30.90 C, stirring speed = 158 rpm, 15.7% inoculum, FeSO 4 . 7H 2 O concentration at 13.83 g/L and (NH 4 ) 2 SO 4 concentration at 3.22 g/L which achieved 83% of uranium extraction efficiency. The results of uranium bioleaching experiment using optimized parameter showed 81% uranium extraction during 15 d. The obtained results reveal that using RSM is reliable and appropriate for optimization of parameters involved in the uranium bioleaching process.

A Model for High-Strain-Rate Deformation of Uranium-Niobium Alloys

Energy Technology Data Exchange (ETDEWEB)

F.L.Addessio; Q.H.Zuo; T.A.Mason; L.C.Brinson

2003-05-01

A thermodynamic approach is used to develop a framework for modeling uranium-niobium alloys under the conditions of high strain rate. Using this framework, a three-dimensional phenomenological model, which includes nonlinear elasticity (equation of state), phase transformation, crystal reorientation, rate-dependent plasticity, and porosity growth is presented. An implicit numerical technique is used to solve the evolution equations for the material state. Comparisons are made between the model and data for low-strain-rate loading and unloading as well as for heating and cooling experiments. Comparisons of the model and data also are made for low- and high-strain-rate uniaxial stress and uniaxial strain experiments. A uranium-6 weight percent niobium alloy is used in the comparisons of model and experiment.

Response of plants to high concentrations of uranium stress and the screening of remediation plants

International Nuclear Information System (INIS)

Tang Yongjin; Luo Xuegang; Zeng Feng; Jiang Shijie

2013-01-01

Studies of the resistance and accumulation ability of different plant species to uranium (U) has important influence on the bioremediation of U contaminated soil. The resistance and enrichment ability of high concentrations of U (500 mg · kg"-"1 soil) in fourteen plant species were investigated and evaluated in this study in order to screen remediation plants for governance soil U contamination. The results showed that: (1) high concentrations of U stress had different effects on the emergence and survival of the different plants. The seed emergence of Hibiscus esculentus was reduced by 2/3, but the seed emergence of Gynura cusimbua (D. Don) S. Moore, Chenopodium album L. and Phaseolus vulgaris var. humilis Alef were not reduced. Under the contaminated soil, all the sesamum indicum died within a month after the emergence and the survival number of Amaranth and Iresine herbstii 'Aureo-reticulata' reduced by about 80%. But the survival number of Alternanthera philoxeroides (Mart.) Griseb., Chenopodium album L. and Phaseolus vulgaris var. humilis Alef were not influenced. (2) The biomass of the plants would be reduced by 8-99% in the uranium-contaminated soil. The anti-stress ability of Phaseolus vulgaris var. humilis Alef was the strongest in the fourteen plants, and Cucurbita pepo L., Sorghumbicolor (L.) Moench, Ipomoea aquatica Forsk, Helianthus annuus, Chenopodium album L. and Alternanthera philoxeroides (Mart.) Griseb. showed some the anti-stress ability. (3) Significant differences were found in the capacity of plants to absorb uranium between under high-uranium contaminated soil and under the non-uranium contaminated soil were. The plants with higher uranium content in thenon-contaminated soil were Gomphrena globosa, and Cucurbita pepo L., which were 2.249 mg · kg"-"1 DW and 1.620 mg · kg"-"1 DW, respectively. But the plants with higher uranium content in the high uranium contaminated soil were Cichorium intybus L., Amaranth and Ipomoea aquatica Forsk, which

The study towards high intensity high charge state laser ion sources.

Science.gov (United States)

Zhao, H Y; Jin, Q Y; Sha, S; Zhang, J J; Li, Z M; Liu, W; Sun, L T; Zhang, X Z; Zhao, H W

2014-02-01

As one of the candidate ion sources for a planned project, the High Intensity heavy-ion Accelerator Facility, a laser ion source has been being intensively studied at the Institute of Modern Physics in the past two years. The charge state distributions of ions produced by irradiating a pulsed 3 J/8 ns Nd:YAG laser on solid targets of a wide range of elements (C, Al, Ti, Ni, Ag, Ta, and Pb) were measured with an electrostatic ion analyzer spectrometer, which indicates that highly charged ions could be generated from low-to-medium mass elements with the present laser system, while the charge state distributions for high mass elements were relatively low. The shot-to-shot stability of ion pulses was monitored with a Faraday cup for carbon target. The fluctuations within ±2.5% for the peak current and total charge and ±6% for pulse duration were demonstrated with the present setup of the laser ion source, the suppression of which is still possible.

Product Stewardship in Uranium: A Way for the Industry to Demonstrate its High Performance

International Nuclear Information System (INIS)

Harris, Frank

2014-01-01

Conclusions: • Product stewardship is an means for communicating the high performance on health, safety and environment of the nuclear fuel cycle including uranium mining. • It has been effective with other products and is appropriate for uranium. • Can be a vehicle for addressing public concerns across the industry. • Due to uranium’s unique characteristics it has the potential to be a best practice example of product stewardship. • Work is underway in the international arena to progress uranium product stewardship and it represent a unique opportunity to provide whole of industry benefits

Source-driven noise analysis measurements with neptunium metal reflected by high enriched uranium

International Nuclear Information System (INIS)

Valentine, Timothy E.; Mattingly, John K.

2003-01-01

Subcritical noise analysis measurements have been performed with neptunium ( 237 Np) sphere reflected by highly enriched uranium. These measurements were performed at the Los Alamos Critical Experiment Facility in December 2002 to provide an estimate of the subcriticality of 237 Np reflected by various amounts of high-enriched uranium. This paper provides a description of the measurements and presents some preliminary results of the analysis of the measurements. The measured and calculated spectral ratios differ by 15% whereas the 'interpreted' and calculated k eff values differ by approximately 1%. (author)

Fabrication procedures for manufacturing high uranium concentration dispersion fuel elements

International Nuclear Information System (INIS)

Souza, Jose Antonio Batista de

2011-01-01

IPEN-CNEN/SP developed the technology to produce the dispersion type fuel elements for research reactors and made it available for routine production. Today, the fuel produced in IPEN-CNEN/SP is limited to the uranium concentration of 3.0 gU/cm 3 for U 3 Si 2 -Al dispersion-based and 2.3 gU/cm 3 for U 3 O 8 -Al dispersion. The increase of uranium concentration in fuel plates enables the reactivity of the reactor core reactivity to be higher and extends the fuel life. Concerning technology, it is possible to increase the uranium concentration in the fuel meat up to the limit of 4.8 gU/cm 3 in U 3 Si 2 -Al dispersion and 3.2 gU/cm 3 U 3 O 8 -Al dispersion. These dispersions are well qualified worldwide. This work aims to develop the manufacturing process of both fuel meats with high uranium concentrations, by redefining the manufacturing procedures currently adopted in the Nuclear Fuel Center of IPEN-CNEN/SP. Based on the results, it was concluded that to achieve the desired concentration, it is necessary to make some changes in the established procedures, such as in the particle size of the fuel powder and in the feeding process inside the matrix, before briquette pressing. These studies have also shown that the fuel plates, with a high concentration of U 3 Si 2 -Al, met the used specifications. On the other hand, the appearance of the microstructure obtained from U 3 O 8 -Al dispersion fuel plates with 3.2 gU/cm 3 showed to be unsatisfactory, due to the considerably significant porosity observed. The developed fabrication procedure was applied to U 3 Si 2 production at 4.8 gU/cm 3 , with enriched uranium. The produced plates were used to assemble the fuel element IEA-228, which was irradiated in order to check its performance in the IEA-R1 reactor at IPEN-CNEN/SP. These new fuels have potential to be used in the new Brazilian Multipurpose Reactor - RMB. (author)

Development of very-high-density low-enriched-uranium fuels

International Nuclear Information System (INIS)

Snelgrove, J.L.; Hofman, G.L.; Meyer, M.K.; Trybus, C.L.; Wiencek, T.C.

1997-01-01

Following a hiatus of several years and following its successful development and qualification of 4.8 g U cm -3 U 3 Si 2 -Al dispersion fuel for application with low-enriched uranium in research and test reactors, the US Reduced Enrichment for Research and Test Reactors program has embarked on the development of even-higher-density fuels. Our goal is to achieve uranium densities of 8-9 g cm -3 in aluminum-based dispersion fuels. Achieving this goal will require the use of high-density, γ-stabilized uranium alloy powders in conjunction with the most-advanced fuel fabrication techniques. Key issues being addressed are the reaction of the fuel alloys with aluminum and the irradiation behavior of the fuel alloys and any reaction products. Test irradiations of candidate fuels in very-small (micro) plates are scheduled to begin in the Advanced Test Reactor during June, 1997. Initial results are expected to be available in early 1998. We are performing out-of-reactor studies on the phase structure of the candidate alloys on diffusion of the matrix material into the aluminum. In addition, we are modifying our current dispersion fuel irradiation behavior model to accommodate the new fuels. Several international partners are participating in various phases of this work. (orig.)

Uranium/plutonium and uranium/neptunium separation by the Purex process using hydroxyurea

International Nuclear Information System (INIS)

Zhu Zhaowu; He Jianyu; Zhang Zefu; Zhang Yu; Zhu Jianmin; Zhen Weifang

2004-01-01

Hydroxyurea dissolved in nitric acid can strip plutonium and neptunium from tri-butyl phosphate efficiently and has little influence on the uranium distribution between the two phases. Simulating the 1B contactor of the Purex process by hydroxyurea with nitric acid solution as a stripping agent, the separation factors of uranium/plutonium and uranium/neptunium can reach values as high as 4.7 x 10 4 and 260, respectively. This indicates that hydroxyurea is a promising salt free agent for uranium/plutonium and uranium/neptunium separations. (author)

Application of response surface methodology to optimize uranium biological leaching at high pulp density

Energy Technology Data Exchange (ETDEWEB)

Fatemi, Faezeh; Arabieh, Masoud; Jahani, Samaneh [NSTRI, Tehran (Iran, Islamic Republic of). Nuclear Fuel Cycle Research School

2016-08-01

The aim of the present study was to carry out uranium bioleaching via optimization of the leaching process using response surface methodology. For this purpose, the native Acidithiobacillus sp. was adapted to different pulp densities following optimization process carried out at a high pulp density. Response surface methodology based on Box-Behnken design was used to optimize the uranium bioleaching. The effects of six key parameters on the bioleaching efficiency were investigated. The process was modeled with mathematical equation, including not only first and second order terms, but also with probable interaction effects between each pair of factors.The results showed that the extraction efficiency of uranium dropped from 100% at pulp densities of 2.5, 5, 7.5 and 10% to 68% at 12.5% of pulp density. Using RSM, the optimum conditions for uranium bioleaching (12.5% (w/v)) were identified as pH = 1.96, temperature = 30.90 C, stirring speed = 158 rpm, 15.7% inoculum, FeSO{sub 4} . 7H{sub 2}O concentration at 13.83 g/L and (NH{sub 4}){sub 2}SO{sub 4} concentration at 3.22 g/L which achieved 83% of uranium extraction efficiency. The results of uranium bioleaching experiment using optimized parameter showed 81% uranium extraction during 15 d. The obtained results reveal that using RSM is reliable and appropriate for optimization of parameters involved in the uranium bioleaching process.

Risk evaluation of uranium mining: a new kinetic approach

Energy Technology Data Exchange (ETDEWEB)

Scislewski, Alexandro [Brazilian Nuclear Energy Comission (CNEN), Avenida Santana, 680, Centro, Caetite-Bahia, 46400-000 (Brazil); Zuddas, Pierpaolo [Universite Pierre et Marie Curie, Paris-Sorbonne, ISTEP place Jussieu, Tour 56-55, case 116, F75252 Paris Cedex 05 (France)

2013-07-01

Release of uranium and associated heavy metals is the main environmental concern regarding exploitation and processing of U-ore. Increasing uranium mining activities potentially increase the risks linked to radiation exposure. As a tool to evaluate these risks, a geochemical inverse modeling approach was developed to estimate the water-mineral interaction in the presence of uranium. Our methodology is based on the estimation of dissolution rate and reactive surface area of the different minerals participating in the reaction by reconstructing the chemical evolution of the interacting fluids. We found that the reactive surface area of parent-rock minerals changes over several orders of magnitude during the investigated reaction time. We propose that the formation of coatings on dissolving mineral surfaces significantly reduces reactivity. Our results show that negatively charged uranium complexes decrease when alkalinity and rock buffer capacity is similarly lower, indicating that the dissolved carbonate is an important parameter impacting uranium mobility. (authors)

Risk evaluation of uranium mining: a new kinetic approach

International Nuclear Information System (INIS)

Scislewski, Alexandro; Zuddas, Pierpaolo

2013-01-01

Release of uranium and associated heavy metals is the main environmental concern regarding exploitation and processing of U-ore. Increasing uranium mining activities potentially increase the risks linked to radiation exposure. As a tool to evaluate these risks, a geochemical inverse modeling approach was developed to estimate the water-mineral interaction in the presence of uranium. Our methodology is based on the estimation of dissolution rate and reactive surface area of the different minerals participating in the reaction by reconstructing the chemical evolution of the interacting fluids. We found that the reactive surface area of parent-rock minerals changes over several orders of magnitude during the investigated reaction time. We propose that the formation of coatings on dissolving mineral surfaces significantly reduces reactivity. Our results show that negatively charged uranium complexes decrease when alkalinity and rock buffer capacity is similarly lower, indicating that the dissolved carbonate is an important parameter impacting uranium mobility. (authors)

Transport of high enriched uranium fresh fuel from Yugoslavia to the Russian federation

OpenAIRE

Pešić Milan P.; Šotić Obrad; Hopwood William H.Jr

2002-01-01

This paper presents the relevant data related to the recent shipment (August 2002) of fresh highly enriched uranium fuel elements from Yugoslavia back to the Russian Federation for uranium down blending. In this way, Yugoslavia gave its contribution to the Reduced Enrichment for Research and Test Reactors (RERTR) Program and to the world's joint efforts to prevent possible terrorist actions against nuclear material potentially usable for the production of nuclear weapons.

Uranium extraction from high content chlorine leach liquor

International Nuclear Information System (INIS)

Fatemi, K.

1998-01-01

In this work uranium solution has been leached out by leaching process of uranium ores from Bandar-Ab bass port using sea water, since fresh water could not be available when it is processed in large scale. Two samples of different batches containing 11 and 20 gr./lit chlorine underwent two stages of precipitation by lead nitrate. As the result of this treatment the chlorine removed and its final concentration reduced to 530 p.p.m. which is well below allowances. Then, the uranium of this recent dechlorinated solu ton has been extracted by T.B.P. Uranium in organic phase was stripped out into inorganic phase by sodium carbonate and precipitated in a form of yellow cake and converted to U3o8. The total recovery of U, was well above 90% and the purity of the conc. U was better than 94%. The lead used at the beginning of the process was recovered for next use

Uranium(III)-carbon multiple bonding supported by arene δ-bonding in mixed-valence hexauranium nanometre-scale rings.

Science.gov (United States)

Wooles, Ashley J; Mills, David P; Tuna, Floriana; McInnes, Eric J L; Law, Gareth T W; Fuller, Adam J; Kremer, Felipe; Ridgway, Mark; Lewis, William; Gagliardi, Laura; Vlaisavljevich, Bess; Liddle, Stephen T

2018-05-29

Despite the fact that non-aqueous uranium chemistry is over 60 years old, most polarised-covalent uranium-element multiple bonds involve formal uranium oxidation states IV, V, and VI. The paucity of uranium(III) congeners is because, in common with metal-ligand multiple bonding generally, such linkages involve strongly donating, charge-loaded ligands that bind best to electron-poor metals and inherently promote disproportionation of uranium(III). Here, we report the synthesis of hexauranium-methanediide nanometre-scale rings. Combined experimental and computational studies suggest overall the presence of formal uranium(III) and (IV) ions, though electron delocalisation in this Kramers system cannot be definitively ruled out, and the resulting polarised-covalent U = C bonds are supported by iodide and δ-bonded arene bridges. The arenes provide reservoirs that accommodate charge, thus avoiding inter-electronic repulsion that would destabilise these low oxidation state metal-ligand multiple bonds. Using arenes as electronic buffers could constitute a general synthetic strategy by which to stabilise otherwise inherently unstable metal-ligand linkages.

High Voltage Charge Pump

KAUST Repository

Emira, Ahmed A.; Abdelghany, Mohamed A.; Elsayed, Mohannad Yomn; Elshurafa, Amro M; Salama, Khaled N.

2014-01-01

Various embodiments of a high voltage charge pump are described. One embodiment is a charge pump circuit that comprises a plurality of switching stages each including a clock input, a clock input inverse, a clock output, and a clock output inverse. The circuit further comprises a plurality of pumping capacitors, wherein one or more pumping capacitors are coupled to a corresponding switching stage. The circuit also comprises a maximum selection circuit coupled to a last switching stage among the plurality of switching stages, the maximum selection circuit configured to filter noise on the output clock and the output clock inverse of the last switching stage, the maximum selection circuit further configured to generate a DC output voltage based on the output clock and the output clock inverse of the last switching stage.

High Voltage Charge Pump

KAUST Repository

Emira, Ahmed A.

2014-10-09

Various embodiments of a high voltage charge pump are described. One embodiment is a charge pump circuit that comprises a plurality of switching stages each including a clock input, a clock input inverse, a clock output, and a clock output inverse. The circuit further comprises a plurality of pumping capacitors, wherein one or more pumping capacitors are coupled to a corresponding switching stage. The circuit also comprises a maximum selection circuit coupled to a last switching stage among the plurality of switching stages, the maximum selection circuit configured to filter noise on the output clock and the output clock inverse of the last switching stage, the maximum selection circuit further configured to generate a DC output voltage based on the output clock and the output clock inverse of the last switching stage.

Uranium distribution in Brazilian granitic rocks. Identification of uranium provinces

International Nuclear Information System (INIS)

Tassinari, C.G.G.

1993-01-01

The research characterized and described uranium enriched granitoids in Brazil. They occur in a variety of tectonic environments and are represented by a variety granite types of distinct ages. It may be deduced that in general they have been generated by partial melting process of continental crust. However, some of them, those with tonality composition, indicate a contribution from mantle derived materials, thus suggesting primary uranium enrichment from the upper mantle. Through this study, the identification and characterization of uranium enriched granite or uranium provinces in Brazil can be made. This may also help identify areas with potential for uranium mineralization although it has been note that uranium mineralization in Brazil are not related to the uranium enrichment process. In general the U-anomalous granitoids are composed of granites with alkaline composition and granite ''sensu strictu'' which comprise mainly of syenites, quartz-syenites and biotite-hornblende granites, with ages between 1,800 - 1,300 M.a. The U-anomalous belongings to this period present high Sr initial ratios values, above 0.706, and high Rb contents. Most of the U-enriched granitoids occur within ancient cratonic areas, or within Early to Mid-Proterozoic mobile belts, but after their cratonization. Generally, these granitoids are related to the border zones of the mobile belts or deep crustal discontinuity. Refs, 12 figs, 3 tabs

Uranium producer region of Lagoa Real, Brazil. Guarantee of supply of uranium concentrated (DUA) for the brazilian needs

International Nuclear Information System (INIS)

Matos, Evandro Carele de; Franco, Jamyle Praxedes

2008-01-01

This work focus at the Uranium Province of Lagoa Real, notably considering the geological reserves of uranium already defined (100,000 tones of U 3 O 8 ) and the respective autonomy in providing raw material needed for making fuel elements. The province, based on geo economical parameters, supported by three main vectors (geological model/grade, mining/process route, investment/finance) has been elected to supply the required brazilian demand. Supplying of uranium for the brazilian power plants is in charge of Industrias Nucleares do Brasil - INB and is based on national production. Thus the Industrial Complex of Caetite has been implemented in the state of Bahia, aiming primarily to supply the needs of Angra 1 and Angra 2 power plants. This new production center has the capacity of producing up to 400 tones/yr. of U 3 O 8 . (author)

Validation of KENO V.a for highly enriched uranium systems with hydrogen and/or carbon moderation

International Nuclear Information System (INIS)

Elliott, E.P.; Vornehm, R.G.; Dodds, H.L. Jr.

1993-01-01

This paper describes the validation in accordance with ANSI/ANS-8.1-1983(R1988) of KENO V.a using the 27-group ENDF/B-IV cross-section library for systems containing highly-enriched uranium, carbon, and hydrogen and for systems containing highly-enriched uranium and carbon with high carbon to uranium (C/U) atomic ratios. The validation has been performed for two separate computational platforms: an IBM 3090 mainframe and an HP 9000 Model 730 workstation, both using the Oak Ridge Y-12 Plant Nuclear Criticality Safety Software (NCSS) code package. Critical experiments performed at the Oak Ridge Critical Experiments Facility, in support of the Rover reactor program, and at the Pajarito site at Los Alamos National Laboratory were identified as having the constituents desired for this validation as well as sufficient experimental detail to allow accurate construction of KENO V.a calculational models. Calculated values of k eff for the Rover experiments, which contain uranium, carbon, and hydrogen, are between 1.0012 ± 0.0026 and 1.0245 ± 0.0023. Calculation of the Los Alamos experiments, which contain uranium and carbon at high C/U ratios, yields values of k eff between 0.9746 ± 0.0028 and 0.9983 ± 0.0027. Safety criteria can be established using this data for both types of systems

Research on geochronology and uranium source of sandstone-hosted uranium ore-formation in major uranium-productive basins, Northern-China

International Nuclear Information System (INIS)

Xia Yuliang; Liu Hanbin; Lin Jinrong; Fan Guang; Hou Yanxian

2004-12-01

A method is developed for correcting uranium content in uranium ore samples by considering the U-Ra equilibrium coefficient, then a U-Pb isochron is drawn up. By performing the above correction ore-formation ages of sandstone-hosted uranium mineralization which may be more realistic have been obtained. The comparative research on U-Pb isotopic ages of detritic zircon in ore-hosting sandstone and zircon in intermediate-acid igneous rocks in corresponding provenance area indicates that the ore-hosting sandstone is originated from the erosion of intermediate-acid igneous rocks and the latters are the material basis for the formation of the uranium-rich sandstone beds. On the basis of the study on U-Pb isotopic system evolution of the provenance rocks and sandstones from ore-hosting series, it is verified that the uranium sources of the sandstone-hosted uranium deposit are: the intermediate-acid igneous rocks with high content of mobile uranium, and the sandstone bodies pre-concentrated uranium. (authors)

Thermal spike analysis of highly charged ion tracks

International Nuclear Information System (INIS)

Karlušić, M.; Jakšić, M.

2012-01-01

The irradiation of material using swift heavy ion or highly charged ion causes excitation of the electron subsystem at nanometer scale along the ion trajectory. According to the thermal spike model, energy deposited into the electron subsystem leads to temperature increase due to electron–phonon coupling. If ion-induced excitation is sufficiently intensive, then melting of the material can occur, and permanent damage (i.e., ion track) can be formed upon rapid cooling. We present an extension of the analytical thermal spike model of Szenes for the analysis of surface ion track produced after the impact of highly charged ion. By applying the model to existing experimental data, more than 60% of the potential energy of the highly charged ion was shown to be retained in the material during the impact and transformed into the energy of the thermal spike. This value is much higher than 20–40% of the transferred energy into the thermal spike by swift heavy ion. Thresholds for formation of highly charged ion track in different materials show uniform behavior depending only on few material parameters.

Transport of high enriched uranium fresh fuel from Yugoslavia to the Russian federation

Directory of Open Access Journals (Sweden)

Pešić Milan P.

2002-01-01

Full Text Available This paper presents the relevant data related to the recent shipment (August 2002 of fresh highly enriched uranium fuel elements from Yugoslavia back to the Russian Federation for uranium down blending. In this way, Yugoslavia gave its contribution to the Reduced Enrichment for Research and Test Reactors (RERTR Program and to the world's joint efforts to prevent possible terrorist actions against nuclear material potentially usable for the production of nuclear weapons.

Progress in developing very-high-density low-enriched-uranium fuels

International Nuclear Information System (INIS)

Snelgrove, J.L.; Hofman, G.L.; Meyer, M.K.; Hayes, S.L.; Wiencek, T.C.; Strain, R.V.

1999-01-01

Preliminary results from the postirradiation examinations of microplates irradiated in the RERTR-1 and -2 experiments in the ATR have shown several binary and ternary U-Mo alloys to be promising candidates for use in aluminum-based dispersion fuels with uranium densities up to 8 to 9 g/cm 3 . Ternary alloys of uranium, niobium, and zirconium performed poorly, however, both in terms of fuel/matrix reaction and fission-gas-bubble behavior, and have been dropped from further study. Since irradiation temperatures achieved in the present experiments (approximately 70 deg. C) are considerably lower than might be experienced in a high-performance reactor, a new experiment is being planned with beginning-of-cycle temperatures greater than 200 deg. C in 8-g U/cm 3 fuel. (author)

Titrimetric determination of uranium

International Nuclear Information System (INIS)

Florence, T.M.

1989-01-01

Titrimetric methods are almost invariably used for the high precision assay of uranium compounds, because gravimetric methods are nonselective, and not as reliable. Although precipitation titrations have been used, for example with cupferron and ferrocyanide, and chelate titrations with EDTA and oxine give reasonable results, in practice only redox titrations find routine use. With all redox titration methods for uranium a precision of 01 to 02 percent can be achieved, and precisions as high as 0.003 percent have been claimed for the more refined techniques. There are two types of redox titrations for uranium in common use. The first involves the direct titration of uranium (VI) to uranium (IV) with a standard solution of a strong reductant, such as chromous chloride or titanous chloride, and the second requires a preliminary reduction of uranium to the (IV) or (III) state, followed by titration back to the (VI) state with a standard oxidant. Both types of redox titrations are discussed. 4 figs

Release of gases from uranium metal at high temperatures

International Nuclear Information System (INIS)

Sayi, Y.S.; Ramanjaneyulu, P.S.; Yadav, C.S.; Shankaran, P.S.; Chhapru, G.C.; Ramakumar, K.L.; Venugopal, V.

2008-01-01

Depending on the ambient environmental conditions, different gaseous species could get entrapped in uranium metal ingots or pellets. On heating, melting or vapourising uranium metal, these get released and depending on the composition, may cause detrimental effects either within the metal matrix itself or on the surrounding materials/environment. For instance, these gases may affect the performance of the uranium metal, which is used as fuel in the heavy water moderated research reactors, CIRUS and DHRUVA. Hence, detailed investigations have been carried out on the release of gases over a temperature range 875-1500 K employing hot vacuum extraction technique, in specimen uranium pellets made from uranium rods/ingots. Employing an on-line quadrupole mass spectrometer, the analysis of released gases was carried out. The isobaric interference between carbon monoxide and nitrogen at m/e = 28 in the mass spectrometric analysis has been resolved by considering their fragmentation patterns. Since no standards are available to evaluate the results, only the reproducibility is tested. The precision (relative standard deviation at 3σ level) of the method is ±5%. The minimum detectable gas content employing the method is 5.00 x 10 -09 m 3 . About 4 x 10 -04 m 3 /kg of gas is released from uranium pellets, with hydrogen as the main constituent. The gas content increases with storage in air

High-uranium-loaded U3O8-Al fuel element development program [contributed by N.M. Martin, ORNL

International Nuclear Information System (INIS)

Martin, M.M.

1993-01-01

The High-Uranium-Loaded U 3 O 8 -Al Fuel Element Development Program supports Argonne National Laboratory efforts to develop high-uranium-density research and test reactor fuel to accommodate use of low-uranium enrichment. The goal is to fuel most research and test reactors with uranium of less than 20% enrichment for the purpose of lowering the potential for diversion of highly-enriched material for nonpeaceful usages. The specific objective of the program is to develop the technological and engineering data base for U 3 O 8 -Al plate-type fuel elements of maximal uranium content to the point of vendor qualification for full scale fabrication on a production basis. A program and management plan that details the organization, supporting objectives, schedule, and budget is in place and preparation for fuel and irradiation studies is under way. The current programming envisions a program of about four years duration for an estimated cost of about two million dollars. During the decades of the fifties and sixties, developments at Oak Ridge National Laboratory led to the use of U 3 O 8 -Al plate-type fuel elements in the High Flux Isotope Reactor, Oak Ridge Research Reactor, Puerto Rico Nuclear Center Reactor, and the High Flux Beam Reactor. Most of the developmental information however applies only up to a uranium concentration of about 55 wt % (about 35 vol % U 3 O 8 ). The technical issues that must be addressed to further increase the uranium loading beyond 55 wt % involve plate fabrication phenomena of voids and dogboning, fuel behavior under long irradiation, and potential for the thermite reaction between U 3 O 8 and aluminum. (author)

Anomalously high concentrations of uranium, radium and radon in water from drilled wells in the Helsinki region

International Nuclear Information System (INIS)

Asikainen, M.; Kahlos, H.

1979-01-01

The concentrations of uranium, 226 Ra and 222 Rn were determined in 308 drilled and 58 dug wells in the Helsinki region. The study area was about 400 km 2 and geologically highly variable, with granites, amphibolites and migmatites the dominant rocks. The radioactivity of water in the dug wells was on a 'normal' level, but in numerous drilled wells it was anomalously high. In 14 drilled wells the concentration of uranium exceeded 1000 μg/l, the highest concentration being 14,870 μg/l. For 222 Rn the maximum concentration was 880,000 pCi/l. The 226 Ra/ 228 Ra and 230 Th/ 232 Th activity ratios showed the isotopes of the uranium series to be dominant in the study area. A state of disequilibrium between 238 U and 234 U was very common in the samples. The 234 U/ 238 U activity ratios varied in the range 1.0 to 4.0 regardless of the amount of uranium in the water. The conclusion can be drawn from the isotopic data that the high radioactivity of water is in some cases caused by primary uranium mineralizations, but mostly by uranium deposited in fissures of the bedrock. The paper includes a summary of the results of two studies carried out between 1967 and 1977. (author)

Structural Arrangement of Water Molecules around Highly Charged Nanoparticles: Molecular Dynamics Simulation

International Nuclear Information System (INIS)

Kim, Eunae; Yeom, Min Sun

2014-01-01

Molecular dynamics simulations were performed to understand the structural arrangement of water molecules around highly charged nanoparticles under aqueous conditions. The effect of two highly charged nanoparticles on the solvation charge asymmetry has been examined. We calculated the radial distribution functions of the components of water molecules around nanoparticles which have four charge types at two different salt concentrations. Even though the distributions of water molecules surrounding a sodium ion and a chloride ion are hardly affected by the charges of nanoparticles and the salt concentrations, those around highly charged nanoparticles are strongly influenced by the charges of nanoparticles, but hardly by the charges of nanoparticles and salt concentrations. We find that the distributions of hydrogen atoms in water molecules around one highly charged nanoparticle are dependent on the magnitude of the nanoparticle charge

High-LET charged particle radiotherapy

International Nuclear Information System (INIS)

Castro, J.R.; California Univ., San Francisco, CA

1991-07-01

The Department of Radiation Oncology at UCSF Medical Center and the Radiation Oncology Department at UC Lawrence Berkeley Laboratory have been evaluating the use of high LET charged particle radiotherapy in a Phase 1--2 research trial ongoing since 1979. In this clinical trail, 239 patients have received at least 10 Gy (physical) minimum tumor dose with neon ions, meaning that at least one-half of their total treatment was given with high-LET charged particle therapy. Ninety-one patients received all of their therapy with neon ions. Of the 239 patients irradiated, target sites included lesions in the skin, subcutaneous tissues, head and neck such as paranasal sinuses, nasopharynx and salivary glands (major and minor), skull base and juxtaspinal area, GI tract including esophagus, pancreas and biliary tract, prostate, lung, soft tissue and bone. Analysis of these patients has been carried out with a minimum followup period of 2 years

31 CFR 540.309 - Natural uranium.

Science.gov (United States)

2010-07-01

... 31 Money and Finance: Treasury 3 2010-07-01 2010-07-01 false Natural uranium. 540.309 Section 540... FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY HIGHLY ENRICHED URANIUM (HEU) AGREEMENT ASSETS CONTROL REGULATIONS General Definitions § 540.309 Natural uranium. The term natural uranium means uranium found in...

Charge-state correlated cross sections for the production of low-velocity highly charged Ne ions by heavy-ion bombardment

International Nuclear Information System (INIS)

Gray, T.J.; Cocke, C.L.; Justiniano, E.

1980-01-01

We report measured cross sections for the collisional production of highly charged low-velocity Ne recoil ions resulting from the bombardment of a thin Ne gas target by highly charged 1-MeV/amu C, N, O, and F projectiles. The measurements were made using time-of-flight techniques which allowed the simultaneous identification of the final charge state of both the low-velocity recoil ion and the high-velocity projectile for each collision event. For a given incident-projectile charge state, the recoil charge-state distribution is very dependent upon the final charge state of the projectile. Single- and double-electron capture events by incident bare nuclei and projectile K-shell ionization during the collision cause large shifts in the recoil charge-state distributions toward higher charge states. A previously proposed energy-deposition model is modified to include the effects of projectile charge-changing collisions during the collision for bare and hydrogenlike projectiles and is used to discuss the present experimental results

Charged dust in planetary magnetospheres: Hamiltonian dynamics and numerical simulations for highly charged grains

Science.gov (United States)

Schaffer, L.; Burns, J. A.

1994-01-01

We use a combination of analytical and numerical methods to investigate the dynamics of charged dust grains in planetary magnetospheres. Our emphasis is on obtaining results valid for particles that are not necessarily dominated either by gravitational or electromagnetic forces. A Hamiltonian formulation of the problem yields exact results, for all values of charge-to-mass ratio, when we introduce two constraints: particles remain in the equatorial plane and the magnetic field is taken as axially symmetric. In particular, we obtain locations of equilibrium points, the frequencies of stable periodic orbits, the topology of separatrices in phase space, and the rate of longitudinal drift. These results are significant for specific applications: motion in the nearly aligned dipolar field of Saturn, and the trajectories of arbitrarily charged particles in complex magnetic fields for limited periods of time after ejection from parent bodies. Since the model is restrictive, we also use numerical integrations of the full three-dimensional equations of motion and illustrate under what conditions the constrained problem yields reasonable results. We show that a large fraction of the intermediately charged and highly charged (gyrating) particles will always be lost to a planet's atmosphere within a few hundred hours, for motion through tilted-dipole magnetic fields. We find that grains must have a very high charge-to-mass ratio in order to be mirrored back to the ring plane. Thus, except perhaps at Saturn where the dipole tilt is very small, the likely inhabitants of the dusty ring systems are those particles that are either nearly Keplerian (weakly charged) grains or grains whose charges place them in the lower end of the intermediate charge zone. Fianlly, we demonstrate the effect of plasma drag on the orbits of gyrating particles to be a rapid decrease in gyroradius followed by a slow radial evolution of the guiding center.

Analysis of uranium intake, risk assessments uranium content in blood and urine

International Nuclear Information System (INIS)

Mukesh Kumar; Prasher, Sangeeta; Singh, Surinder

2015-01-01

Bathinda district of Punjab is in light since the last few years because of the high mortality rate due to cancer. In order to explore the possibility of uranium as one of the causes for cancer an attempt has been made to estimate the level of uranium in the environmental samples viz. soil, water, food items and to correlate it with that in the blood and urine of the cancer patients and the normal persons of the area. The fission track technique has been employed for such studies. Though the uranium content in soil is normal and close to the world average, the uranium values in most of the water samples exceed the recommended safe limits. The cancer risk estimate from drinking of uranium contaminated water during the life time of sixty year is very high. The daily intake of Uranium for the population of these villages including the drinking water has also been estimated using the daily intake of these foodstuffs recommended by WHO and is found to exceed the typical world wide dietary intake of 0.9-4.5 μg/day. The concentration of uranium in urine and blood is found higher in cancer patients, whereas the urine excretion of uranium is lower in the cancer patients compared to the normal persons. (author)

Ion optics and beam dynamics optimization at the HESR storage ring for the SPARC experiments with highly charged heavy ions

International Nuclear Information System (INIS)

Kovalenko, Oleksandr

2015-01-01

The High-Energy Storage Ring (HESR) is a part of an upcoming International Facility for Antiproton and Ion Research (FAIR) at GSI in Darmstadt. A key part of a scientific program, along with antiproton physics, will be physics with highly-charged heavy ions. Phase-space cooled beams together with fixed internal target will provide an excellent environment for storage ring experiments at the HESR for the SPARC collaboration. Until recently, however, the existing ion optical lattice for the HESR was designed only for the experiments with antiproton beams. The thesis presents a new ion optical mode developed specifically for the operation of the HESR with highly charged heavy ions. The presence of the errors, such as beam momentum spread, magnetic field impurities or magnets misalignments, leads to disruption of beam dynamics: exciting of resonant motion and loss of beam stability. Within the paper, these effects are investigated with the help of numerical codes for particle accelerator design and simulation MAD-X and MIRKO. A number of correction techniques are applied to minimize the nonlinear impact on the beam dynamics and improve the experimental conditions. The application of the analytical and numerical tools is demonstrated in the experiment with uranium U 90+ beam at the existing storage ring ESR, GSI.

Ion optics and beam dynamics optimization at the HESR storage ring for the SPARC experiments with highly charged heavy ions

Energy Technology Data Exchange (ETDEWEB)

Kovalenko, Oleksandr

2015-06-24

The High-Energy Storage Ring (HESR) is a part of an upcoming International Facility for Antiproton and Ion Research (FAIR) at GSI in Darmstadt. A key part of a scientific program, along with antiproton physics, will be physics with highly-charged heavy ions. Phase-space cooled beams together with fixed internal target will provide an excellent environment for storage ring experiments at the HESR for the SPARC collaboration. Until recently, however, the existing ion optical lattice for the HESR was designed only for the experiments with antiproton beams. The thesis presents a new ion optical mode developed specifically for the operation of the HESR with highly charged heavy ions. The presence of the errors, such as beam momentum spread, magnetic field impurities or magnets misalignments, leads to disruption of beam dynamics: exciting of resonant motion and loss of beam stability. Within the paper, these effects are investigated with the help of numerical codes for particle accelerator design and simulation MAD-X and MIRKO. A number of correction techniques are applied to minimize the nonlinear impact on the beam dynamics and improve the experimental conditions. The application of the analytical and numerical tools is demonstrated in the experiment with uranium U{sup 90+} beam at the existing storage ring ESR, GSI.

Beamline for low-energy transport of highly charged ions at HITRAP

International Nuclear Information System (INIS)

Andelkovic, Z.; Herfurth, F.; Kotovskiy, N.; König, K.; Maaß, B.; Murböck, T.; Neidherr, D.; Schmidt, S.; Steinmann, J.; Vogel, M.; Vorobjev, G.

2015-01-01

A beamline for transport of highly charged ions with energies as low as a few keV/charge has been constructed and commissioned at GSI. Complementary to the existing infrastructure of the HITRAP facility for deceleration of highly charged ions from the GSI accelerator, the new beamline connects the HITRAP ion decelerator and an EBIT with the associated experimental setups. Therefore, the facility can now transport the decelerated heavy highly charged ions to the experiments or supply them offline with medium-heavy highly charged ions from the EBIT, both at energies as low as a few keV/charge. Here we present the design of the 20 m long beamline with the corresponding beam instrumentation, as well as its performance in terms of energy and transport efficiency

Uranium geochemistry, mineralogy, geology, exploration and resources

International Nuclear Information System (INIS)

De Vivo, B.

1984-01-01

This book comprises papers on the following topics: history of radioactivity; uranium in mantle processes; transport and deposition of uranium in hydrothermal systems at temperatures up to 300 0 C: Geological implications; geochemical behaviour of uranium in the supergene environment; uranium exploration techniques; uranium mineralogy; time, crustal evolution and generation of uranium deposits; uranium exploration; geochemistry of uranium in the hydrographic network; uranium deposits of the world, excluding Europe; uranium deposits in Europe; uranium in the economics of energy; role of high heat production granites in uranium province formation; and uranium deposits

Preparation of uranium-plutonium mixed nitride pellets with high purity

International Nuclear Information System (INIS)

Arai, Yasuo; Shiozawa, Ken-ichi; Ohmichi, Toshihiko

1992-01-01

Uranium-plutonium mixed nitride pellets have been prepared in the gloveboxes with high purity Ar gas atmosphere. Carbothermic reduction of the oxides in N 2 -H 2 mixed gas stream was adopted for synthesizing mixed nitride. Sintering was carried out in various conditions and the effect on the pellet characteristics was investigated. (author)

Production of highly charged ion beams with SECRAL

International Nuclear Information System (INIS)

Sun, L. T.; Zhao, H. W.; Zhang, X. Z.; Feng, Y. C.; Li, J. Y.; Guo, X. H.; Ma, H. Y.; Zhao, H. Y.; Ma, B. H.; Wang, H.; Li, X. X.; Jin, T.; Xie, D. Z.; Lu, W.; Cao, Y.; Shang, Y.

2010-01-01

Superconducting electron cyclotron resonance ion source with advanced design in Lanzhou (SECRAL) is an all-superconducting-magnet electron cyclotron resonance ion source (ECRIS) for the production of intense highly charged ion beams to meet the requirements of the Heavy Ion Research Facility in Lanzhou (HIRFL). To further enhance the performance of SECRAL, an aluminum chamber has been installed inside a 1.5 mm thick Ta liner used for the reduction of x-ray irradiation at the high voltage insulator. With double-frequency (18+14.5 GHz) heating and at maximum total microwave power of 2.0 kW, SECRAL has successfully produced quite a few very highly charged Xe ion beams, such as 10 e μA of Xe 37+ , 1 e μA of Xe 43+ , and 0.16 e μA of Ne-like Xe 44+ . To further explore the capability of the SECRAL in the production of highly charged heavy metal ion beams, a first test run on bismuth has been carried out recently. The main goal is to produce an intense Bi 31+ beam for HIRFL accelerator and to have a feel how well the SECRAL can do in the production of very highly charged Bi beams. During the test, though at microwave power less than 3 kW, more than 150 e μA of Bi 31+ , 22 e μA of Bi 41+ , and 1.5 e μA of Bi 50+ have been produced. All of these results have again demonstrated the great capability of the SECRAL source. This article will present the detailed results and brief discussions to the production of highly charged ion beams with SECRAL.

Management of high enriched uranium for peaceful purposes: Status and trends

International Nuclear Information System (INIS)

2005-06-01

Arms control agreements between some Nuclear Weapon States have led to the dismantling of many of the nuclear weapons in their military stockpiles, which in turn have produced stockpiles of excess weapons-grade high enriched uranium (HEU) from the dismantled weapons. Considering the proliferation potential of HEU, the management, control and disposition of this fissile material has become a primary focus of nuclear non-proliferation efforts worldwide. To lessen the proliferation threat of excess HEU stockpiles, the USA agreed to purchase several tonnes of excess Russian HEU down-blended to low enriched uranium (LEU). Proliferation concerns about HEU have also resulted in a global effort to convert research reactors from HEU to LEU fuel and to minimize civilian use of HEU. This publication addresses HEU management declared excesses, non-proliferation programmes and options for the use of HEU stockpiles, including disposition programmes. Also addressed are the influence of LEU derived from surplus HEU on the global market for uranium, technical issues associated with utilization and the disposition of HEU

Spectrographic determination of impurities in uranium tetrafluoride

International Nuclear Information System (INIS)

Capdevila Perez, C.; Roca Adell, M.; Alvarez Gonzalez, F.

1967-01-01

A carrier distillation method for the determination of Ag, Al, As, B, Cd, Cr, Cu, Fe, Mg, Mn, Ni, Pb, and Si in uranium tetrafluoride was develop ped. the previous addition of 25% Y 2 3 prevents the excitation of uranium by conversion of the volatile UF 4 into U 3 0 8 during the arc discharge. NaCl or Ga 2 0 3 , containing Ge and V as internal standards, are used as carriers, and samples are arced in 10 Amp. d.c. arc in a graphite anode cup. 7 mm diameter, 10 mm deep, being the weight of charge 300 mg. (Author) 14 refs

Continued Multicolumns Bioleaching for Low Grade Uranium Ore at a Certain Uranium Deposit

OpenAIRE

Gongxin Chen; Zhanxue Sun; Yajie Liu

2016-01-01

Bioleaching has lots of advantages compared with traditional heap leaching. In industry, bioleaching of uranium is still facing many problems such as site space, high cost of production, and limited industrial facilities. In this paper, a continued column bioleaching system has been established for leaching a certain uranium ore which contains high fluoride. The analysis of chemical composition of ore shows that the grade of uranium is 0.208%, which is lower than that of other deposits. Howev...

Discussion on prospecting potential for rich uranium deposits in Xiazhuang uranium ore-field, northern Guangdong

International Nuclear Information System (INIS)

Wu Lieqin; Tan Zhengzhong

2004-01-01

Based on analyzing the prospecting potential for uranium deposits in Xiazhuang uranium ore field this paper discusses the prospecting for rich uranium deposits and prospecting potential in the region. Research achievements indicate: that the Xiazhuang ore-field is an ore-concentrated area where uranium has been highly enriched, and possesses good prospecting potential and perspective, becoming one of the most important prospecting areas for locating rich uranium deposits in northern Guangdong; that the 'intersection type', the alkaline metasomatic fractured rock type and the vein-group type uranium deposits are main targets and the prospecting direction for future uranium prospecting in this region

Surplus Highly Enriched Uranium Disposition Program plan

International Nuclear Information System (INIS)

1996-10-01

The purpose of this document is to provide upper level guidance for the program that will downblend surplus highly enriched uranium for use as commercial nuclear reactor fuel or low-level radioactive waste. The intent of this document is to outline the overall mission and program objectives. The document is also intended to provide a general basis for integration of disposition efforts among all applicable sites. This plan provides background information, establishes the scope of disposition activities, provides an approach to the mission and objectives, identifies programmatic assumptions, defines major roles, provides summary level schedules and milestones, and addresses budget requirements

High temperature behavior of metallic inclusions in uranium dioxide

International Nuclear Information System (INIS)

Yang, R.L.

1980-08-01

The object of this thesis was to construct a temperature gradient furnace to simulate the thermal conditions in the reactor fuel and to study the migration of metallic inclusions in uranium oxide under the influence of temperature gradient. No thermal migration of molybdenum and tungsten inclusions was observed under the experimental conditions. Ruthenium inclusions, however, dissolved and diffused atomically through grain boundaries in slightly reduced uranium oxide. An intermetallic compound (probably URu 3 ) was formed by reaction of Ru and UO/sub 2-x/. The diffusivity and solubility of ruthenium in uranium oxide were measured

Uranium market and resources

International Nuclear Information System (INIS)

Capus, G.; Arnold, Th.

2004-01-01

The controversy about the extend of the uranium resources worldwide is still important, this article sheds some light on this topic. Every 2 years IAEA and NEA (nuclear energy agency) edit an inventory of uranium resources as reported by contributing countries. It appears that about 4.6 millions tons of uranium are available at a recovery cost less than 130 dollars per kg of uranium and a total of 14 millions tons of uranium can be assessed when including all existing or supposed resources. In fact there is enough uranium to sustain a moderate growth of the park of nuclear reactors during next decades and it is highly likely that the volume of uranium resources can allow a more aggressive development of nuclear energy. It is recalled that a broad use of the validated breeder technology can stretch the durability of uranium resources by a factor 50. (A.C.)

Charged current weak interactions at high energy

International Nuclear Information System (INIS)

Cline, D.

1977-01-01

We review high energy neutrino and antineutrino charged current interactions. An overview of the experimental data is given, including a discussion of the experimental status of the y anomaly. Locality tests, μ-e universality and charge symmetry invariance tests are discussed. Charm production is discussed. The experimental status of trimuon events and possible phenomenological models for these events are presented. (orig.) [de

In vivo measurement of uranium in the human chest under high background conditions

International Nuclear Information System (INIS)

Kruger, P.J.; Feather, J.I.

1981-08-01

The use of a low-background counting room was considered essential for in vivo gamma counting of uranium in the human chest. When such measurements were, however, carried out under relatively high background conditions, this necessitated a new method of analysis. It was found that a linear relationship between LnN and E exists for each individual where N is the count rate per keV and E the energy in keV, for gamma energies between 90 keV and 300 keV. The displacements from this straight line at the energy values of 90 and 186 keV then represent the contribution of the uranium present. These displacements were calibrated for natural uranium. It was possible to detect contamination levels of lower than half MPLB [af

Fundamental studies of uranium and neptunium redox flow batteries (II)

International Nuclear Information System (INIS)

Shiokawa, Y.; Yamamura, T.; Watanabe, N.

2002-01-01

The atomic power generation entails production of so-called minor actinides and accumulation of depleted uranium. The theoretical and experimental investigations are underway to transmute minor actinides for minimizing the long-term radiotoxicity and reducing the radioactive waste. The utilization, however, would be alternative means. The actinide redox couples, An(VI)/An(V) and An(IV)/An(III), have excellent properties as battery active materials. Here j the uranium and neptunium redox flow batteries for the electric power storage are discussed from the electrochemical properties of U, Np, Pu and Am [1,2]. One of the required properties for the batteries for electric power storage is high energy efficiency, which is defined by the ratio of the discharge energy to the charge energy. These energies are dependent on the rapidness of kinetics in the electrode reactions, namely the standard rate constants and also the internal resistance of the battery

HIGHLY ENRICHED URANIUM BLEND DOWN PROGRAM AT THE SAVANNAH RIVER SITE PRESENT AND FUTURE

International Nuclear Information System (INIS)

Magoulas, V; Charles Goergen, C; Ronald Oprea, R

2008-01-01

The Department of Energy (DOE) and Tennessee Valley Authority (TVA) entered into an Interagency Agreement to transfer approximately 40 metric tons of highly enriched uranium (HEU) to TVA for conversion to fuel for the Browns Ferry Nuclear Power Plant. Savannah River Site (SRS) inventories included a significant amount of this material, which resulted from processing spent fuel and surplus materials. The HEU is blended with natural uranium (NU) to low enriched uranium (LEU) with a 4.95% 235U isotopic content and shipped as solution to the TVA vendor. The HEU Blend Down Project provided the upgrades needed to achieve the product throughput and purity required and provided loading facilities. The first blending to low enriched uranium (LEU) took place in March 2003 with the initial shipment to the TVA vendor in July 2003. The SRS Shipments have continued on a regular schedule without any major issues for the past 5 years and are due to complete in September 2008. The HEU Blend program is now looking to continue its success by dispositioning an additional approximately 21 MTU of HEU material as part of the SRS Enriched Uranium Disposition Project

Impact Of Low Grade Uranium Ores On The Echo System and the Workers of Phosphate Industry

International Nuclear Information System (INIS)

Anwar, S.M.

1999-01-01

The present study aims to investigate the influence of uranium present in phosphate rocks as an environmental factor in the ccho system and on the workers of Abu-Zaabal Phosphate Company subjected to the inhalation of big quantities of rock phosphate dust during the benefication of the ore and the production of the fertilizers. Besides. extra amount of uranium reach the workers also through two path ways.The first is direct through eating contaminated planted grown in the near by area.The second is indirect through eating animals fed with contaminated plants. The uranium content is estimated in the soil samples at different depths, water (irrigation and drainage), air samples and plant samples (shoot and root) in Berseem from the four directions, urine samples from twenty workers in charge of the processing of phosphate compared to twenty volunteers far from the contaminated area.The results showed an elevated values for phosphorus and uranium in the air, water. soil and plant (Berseem) around Abu Zaabal Factory and extending to about 2 km from all directions. Urine may be considered as a biological indicator medium for the uptake of uranium in uranium miners and the workers in charge of ore processing and can represent the major route of excretion for the absorbed metal. Significant differences were shown between the uranium level in the urine of workers group and the control group

A high charge state heavy ion beam source for HIF

International Nuclear Information System (INIS)

Eylon, S.; Henestroza, E.

1995-04-01

A high current low emittance high charge state heavy ion beam source is being developed. This is designed to deliver HIF (heavy ion fusion) driver accelerator scale beam. Using high-charge-state beam in a driver accelerator for HIF may increase the acceleration efficiency, leading to a reduction in the driver accelerator size and cost. The proposed source system which consists of the gas beam electron stripper followed by a high charge state beam separator, can be added to existing single charge state, low emittance, high brightness ion sources and injectors. We shall report on the source physics design using 2D beam envelope simulations and experimental feasibility studies' results using a neutral gas stripper and a beam separator at the exit of the LBL 2 MV injector

Uranium geochemistry in soil and groundwater at the F and H seepage basins

International Nuclear Information System (INIS)

Serkiz, S.M.; Johnson, W.H.

1994-09-01

For 33 years, low activity liquid wastes from the chemical separation areas at the U.S. Department of Energy's Savannah River Site were disposed of in unlined seepage basins. Soil and associated pore water samples of widely varying groundwater chemistries and contaminant concentrations were collected from the region downgradient of these basins using cone penetrometer technology. Analysis of samples using inductively coupled plasma - mass spectrometry has allowed the investigation of uranium partitioning between the aqueous phase and soil surfaces at this site. The distribution of uranium was examined with respect to the solution and soil chemistry (e.g., pH, redox potential, cation and contaminant concentration) and aqueous-phase chemical speciation modeling. The uranium soil source term at the F- and H-Area Seepage Basins (FHSB) is much smaller than has been used in previous modeling efforts. This should result in a much shorter remediation time and a greater effectiveness of a pump-and-treat design than previously predicted. Distribution coefficients at the (FHSB) were found to vary between 1.2 to 34,000 1 kg -1 for uranium. Differences in sorption of these elements can be explained primarily by changes in aqueous pH and the associated change in soil surface charge. Sorption models were fit directly to sorption isotherms from field samples. All models underestimated the fraction of uranium bound at low aqueous uranium concentrations. Linear models overestimated bound uranium at locations where the aqueous concentration was greater than 500 ppb. Mechanistic models provided a much better estimate of the bound uranium concentrations, especially at high aqueous concentrations. Since a large fraction of the uranium at the site is associated with the low-pH portion of the plume, consideration should be given to pumping water from the lowest pH portions of the plume in the F-Area

Preparation of High Purity, High Molecular-Weight Chitin from Ionic Liquids for Use as an Adsorbate for the Extraction of Uranium from Seawater

Energy Technology Data Exchange (ETDEWEB)

Rogers, Robin [Univ. of Alabama, Tuscaloosa, AL (United States)

2013-12-21

Ensuring a domestic supply of uranium is a key issue facing the wider implementation of nuclear power. Uranium is mostly mined in Kazakhstan, Australia, and Canada, and there are few high-grade uranium reserves left worldwide. Therefore, one of the most appealing potential sources of uranium is the vast quantity dissolved in the oceans (estimated to be 4.4 billion tons worldwide). There have been research efforts centered on finding a means to extract uranium from seawater for decades, but so far none have resulted in an economically viable product, due in part to the fact that the materials that have been successfully demonstrated to date are too costly (in terms of money and energy) to produce on the necessary scale. Ionic Liquids (salts which melt below 100{degrees}C) can completely dissolve raw crustacean shells, leading to recovery of a high purity, high molecular weight chitin powder and to fibers and films which can be spun directly from the extract solution suggesting that continuous processing might be feasible. The work proposed here will utilize the unprecedented control this makes possible over the chitin fiber a) to prepare electrospun nanofibers of very high surface area and in specific architectures, b) to modify the fiber surfaces chemically with selective extractant capacity, and c) to demonstrate their utility in the direct extraction and recovery of uranium from seawater. This approach will 1) provide direct extraction of chitin from shellfish waste thus saving energy over the current industrial process for obtaining chitin; 2) allow continuous processing of nanofibers for very high surface area fibers in an economical operation; 3) provide a unique high molecular weight chitin not available from the current industrial process, leading to stronger, more durable fibers; and 4) allow easy chemical modification of the large surface areas of the fibers for appending uranyl selective functionality providing selectivity and ease of stripping. The

Preparation of High Purity, High Molecular-Weight Chitin from Ionic Liquids for Use as an Adsorbate for the Extraction of Uranium from Seawater

International Nuclear Information System (INIS)

Rogers, Robin

2013-01-01

Ensuring a domestic supply of uranium is a key issue facing the wider implementation of nuclear power. Uranium is mostly mined in Kazakhstan, Australia, and Canada, and there are few high-grade uranium reserves left worldwide. Therefore, one of the most appealing potential sources of uranium is the vast quantity dissolved in the oceans (estimated to be 4.4 billion tons worldwide). There have been research efforts centered on finding a means to extract uranium from seawater for decades, but so far none have resulted in an economically viable product, due in part to the fact that the materials that have been successfully demonstrated to date are too costly (in terms of money and energy) to produce on the necessary scale. Ionic Liquids (salts which melt below 100 deg C) can completely dissolve raw crustacean shells, leading to recovery of a high purity, high molecular weight chitin powder and to fibers and films which can be spun directly from the extract solution suggesting that continuous processing might be feasible. The work proposed here will utilize the unprecedented control this makes possible over the chitin fiber a) to prepare electrospun nanofibers of very high surface area and in specific architectures, b) to modify the fiber surfaces chemically with selective extractant capacity, and c) to demonstrate their utility in the direct extraction and recovery of uranium from seawater. This approach will 1) provide direct extraction of chitin from shellfish waste thus saving energy over the current industrial process for obtaining chitin; 2) allow continuous processing of nanofibers for very high surface area fibers in an economical operation; 3) provide a unique high molecular weight chitin not available from the current industrial process, leading to stronger, more durable fibers; and 4) allow easy chemical modification of the large surface areas of the fibers for appending uranyl selective functionality providing selectivity and ease of stripping. The resulting

Uranium-scintillator device

International Nuclear Information System (INIS)

Smith, S.D.

1979-01-01

The calorimeter subgroup of the 1977 ISABELLE Summer Workshop strongly recommended investigation of the uranium-scintillator device because of its several attractive features: (1) increased resolution for hadronic energy, (2) fast time response, (3) high density (i.e., 16 cm of calorimeter per interaction length), and, in comparison with uranium--liquid argon detectors, (4) ease of construction, (5) simple electronics, and (6) lower cost. The AFM group at the CERN ISR became interested in such a calorimeter for substantially the same reasons, and in the fall of 1977 carried out tests on a uranium-scintillator (U-Sc) calorimeter with the same uranium plates used in their 1974 studies of the uranium--liquid argon (U-LA) calorimeter. The chief disadvantage of the scintillator test was that the uranium plates were too small to fully contain the hadronic showers. However, since the scintillator and liquid argon tests were made with the plates, direct comparison of the two types of devices could be made

Status of fuel element technology for plate type dispersion fuels with high uranium density

International Nuclear Information System (INIS)

Hrovat, M.; Huschka, H.; Koch, K.H.; Nazare, S.; Ondracek, G.

1983-01-01

A number of about 20 Material Test and Research Reactors in Germany and abroad is supplied with fuel elements by the company NUKEM. The power of these reactors differs widely ranging from up to about 100 MW. Consequently, the uranium density of the fuel elements in the meat varies considerably depending on the reactor type and is usually within the range from 0.4 to 1.3 g U/cm 3 if HEU is used. In order to convert these reactors to lower uranium enrichment (19.75% 235-U) extensive work is carried out at NUKEM since about two years with the goal to develop fuel elements with high U-density. This work is sponsored by the German Ministry for Research and Technology in the frame of the AF-program. This paper reports on the present state of development for fuel elements with high U-density fuels at NUKEM is reported. The development works were so far concentrated on UAl x , U 3 O 8 and UO 2 fuels which will be described in more detail. In addition fuel plates with new fuels like e.g. U-Si or U-Fe compounds are developed in collaboration with KfK. The required uranium densities for some typical reactors with low, medium, and high power are listed allowing a comparison of HEU and LEU uranium density requirements. The 235-U-content in the case of LEU is raised by 18%. Two different meat thicknesses are considered: Standard thickness of 0.5 mm; and increased thickness of 0.76 mm. From this data compilation the objective follows: in the case of conversion to LEU (19.75% 235-U-enrichment), uranium densities have to be made available up to 24 gU/cm 3 meat for low power level reactors, up to 33 gU/cm 3 meat for medium power level reactors, and between 5.75 and 7.03 g/cm 3 meat for high power level reactors according to this consideration

PHASE ANALYSES OF URANIUM BEARING MINERALS FROM THE HIGH GRADE ORE, NOPAL I, PENA BLANCA, MEXICO

International Nuclear Information System (INIS)

Ren, M.; Goodell, P.; Kelts, A.; Anthony, E.Y.; Fayek, M.; Fan, C.; Beshears, C.

2005-01-01

The Nopal I uranium deposit is located in the Pena Blanca district, approximately 40 miles north of Chihuahua City, Mexico. The deposit was formed by hydrothermal processes within the fracture zone of welded silicic volcanic tuff. The ages of volcanic formations are between 35 to 44 m.y. and there was secondary silicification of most of the formations. After the formation of at least part of the uranium deposit, the ore body was uplifted above the water table and is presently exposed at the surface. Detailed petrographic characterization, electron microprobe backscatter electron (BSE) imagery, and selected x-ray maps for the samples from Nopal I high-grade ore document different uranium phases in the ore. There are at least two stages of uranium precipitation. A small amount of uraninite is encapsulated in silica. Hexavalent uranium may also have been a primary precipitant. The uranium phases were precipitated along cleavages of feldspars, and along fractures in the tuff. Energy dispersive spectrometer data and x-ray maps suggest that the major uranium phases are uranophane and weeksite. Substitutions of Ca and K occur in both phases, implying that conditions were variable during the mineralization/alteration process, and that compositions of the original minerals have a major influence on later stage alteration. Continued study is needed to fully characterize uranium behavior in these semi-arid to arid conditions

PHASE ANALYSES OF URANIUM-BEARING MINERALS FROM THE HIGH GRADE ORE, NOPAL I, PENA BLANCA, MEXICO

Energy Technology Data Exchange (ETDEWEB)

M. Ren; P. Goodell; A. Kelts; E.Y. Anthony; M. Fayek; C. Fan; C. Beshears

2005-07-11

The Nopal I uranium deposit is located in the Pena Blanca district, approximately 40 miles north of Chihuahua City, Mexico. The deposit was formed by hydrothermal processes within the fracture zone of welded silicic volcanic tuff. The ages of volcanic formations are between 35 to 44 m.y. and there was secondary silicification of most of the formations. After the formation of at least part of the uranium deposit, the ore body was uplifted above the water table and is presently exposed at the surface. Detailed petrographic characterization, electron microprobe backscatter electron (BSE) imagery, and selected x-ray maps for the samples from Nopal I high-grade ore document different uranium phases in the ore. There are at least two stages of uranium precipitation. A small amount of uraninite is encapsulated in silica. Hexavalent uranium may also have been a primary precipitant. The uranium phases were precipitated along cleavages of feldspars, and along fractures in the tuff. Energy dispersive spectrometer data and x-ray maps suggest that the major uranium phases are uranophane and weeksite. Substitutions of Ca and K occur in both phases, implying that conditions were variable during the mineralization/alteration process, and that compositions of the original minerals have a major influence on later stage alteration. Continued study is needed to fully characterize uranium behavior in these semi-arid to arid conditions.

Refining of crude uranium by solvent extraction for production of nuclear pure uranium metal

International Nuclear Information System (INIS)

Gupta, S.K.; Manna, S.; Singha, M.; Hareendran, K.N.; Chowdhury, S.; Satpati, S.K.; Kumar, K.

2007-01-01

Uranium is the primary fuel material for any nuclear fission energy program. Natural uranium contains only 0.712% of 235 U as fissile constituent. This low concentration of fissile isotope in natural uranium calls for a very high level of purity, especially with respect to neutron poisons like B, Cd, Gd etc. before it can be used as nuclear fuel. Solvent extraction is a widely used technique by which crude uranium is purified for reactor use. Uranium metal plant (UMP), BARC, Trombay is engaged in refining of uranium concentrate for production of nuclear pure uranium metal for fabrication of fuel for research reactors. This paper reviews some of the fundamental aspects of this refining process with some special references to UMP, BARC. (author)

Chapter 1. General information about uranium. 1.10. Uranium application

International Nuclear Information System (INIS)

Khakimov, N.; Nazarov, Kh.M.; Mirsaidov, I.U.

2011-01-01

Full text: Metallic uranium or its compounds are used as nuclear fuel in nuclear reactors. A natural or low-enriched admixture of uranium isotopes is applied in stationery reactors of nuclear power plants, and products of a high enrichment degree are used in nuclear power plants or in reactors that operates with fast neutrons. 235 U is a source of nuclear energy in nuclear weapons. Depleted uranium is used as armour-piercing core in bombshells. 238 U serves as a source of secondary nuclear fuel - plutonium. (author)

Chapter 1. General information about uranium. 1.10. Uranium application

International Nuclear Information System (INIS)

Khakimov, N.; Nazarov, Kh.M.; Mirsaidov, I.U.

2012-01-01

Full text: Metallic uranium or its compounds are used as nuclear fuel in nuclear reactors. A natural or low-enriched admixture of uranium isotopes is applied in stationery reactors of nuclear power plants, and products of a high enrichment degree are used in nuclear power plants or in reactors that operates with fast neutrons. 235 U is a source of nuclear energy in nuclear weapons. Depleted uranium is used as armour-piercing core in bombshells. 238 U serves as a source of secondary nuclear fuel - plutonium.

Method for the recovery of uranium values from uranium tetrafluoride

International Nuclear Information System (INIS)

Kreuzmann, A.B.

1984-01-01

The invention comprises reacting particulate uranium tetrafluoride and alkaline earth metal oxide (e.g. CaO, MgO) in the presence of gaseous oxygen to effect formation of the corresponding alkaline earth metal uranate and alkaline earth metal fluoride. The product uranate is highly soluble in various acidic solutions whereas the product fluoride is virtually insoluble therein. The product mixture of uranate and alkaline earth metal fluoride is contacted with a suitable acid to provide a uranium-containing solution, from which the uranium is recovered. (author)

Uranium deposits in granitic rocks

International Nuclear Information System (INIS)

Nishimori, R.K.; Ragland, P.C.; Rogers, J.J.W.; Greenberg, J.K.

1977-01-01

This report is a review of published data bearing on the geology and origin of uranium deposits in granitic, pegmatitic and migmatitic rocks with the aim of assisting in the development of predictive criteria for the search for similar deposits in the U.S. Efforts were concentrated on the so-called ''porphyry'' uranium deposits. Two types of uranium deposits are primarily considered: deposits in pegmatites and alaskites in gneiss terrains, and disseminations of uranium in high-level granites. In Chapter 1 of this report, the general data on the distribution of uranium in igneous and metamorphic rocks are reviewed. Chapter 2 contains some comments on the classification of uranium deposits associated with igneous rocks and a summary of the main features of the geology of uranium deposits in granites. General concepts of the behavior of uranium in granites during crustal evolution are reviewed in Chapter 3. Also included is a discussion of the relationship of uranium mineralization in granites to the general evolution of mobile belts, plus the influence of magmatic and post-magmatic processes on the distribution of uranium in igneous rocks and related ore deposits. Chapter 4 relates the results of experimental studies on the crystallization of granites to some of the geologic features of uranium deposits in pegmatites and alaskites in high-grade metamorphic terrains. Potential or favorable areas for igneous uranium deposits in the U.S.A. are delineated in Chapter 5. Data on the geology of specific uranium deposits in granitic rocks are contained in Appendix 1. A compilation of igneous rock formations containing greater than 10 ppM uranium is included in Appendix 2. Appendix 3 is a report on the results of a visit to the Roessing area. Appendix 4 is a report on a field excursion to eastern Canada

Uranium resources in New Mexico

International Nuclear Information System (INIS)

McLemore, V.T.; Chenoweth, W.L.

1989-01-01

For nearly three decades (1951-1980), the Grants uranium district in northwestern New Mexico produced more uranium than any other district in the world. The most important host rocks containing economic uranium deposits in New Mexico are sandstones within the Jurassic Morrison Formation. Approximately 334,506,000 lb of U 3 O 8 were produced from this unit from 1948 through 1987, accounting for 38% of the total uranium production from the US. All of the economic reserves and most of the resources in New Mexico occur in the Morrison Formation. Uranium deposits also occur in sandstones of Paleozoic, Triassic, Cretaceous, Tertiary, and Quaternary formations; however, only 468,680 lb of U 3 O 8 or 0.14% of the total production from New Mexico have been produced from these deposits. Some of these deposits may have a high resource potential. In contrast, almost 6.7 million lb of U 3 O 8 have been produced from uranium deposits in the Todilto Limestone of the Wanakah Formation (Jurassic), but potential for finding additional economic uranium deposits in the near future is low. Other uranium deposits in New Mexico include those in other sedimentary rocks, vein-type uranium deposits, and disseminated magmatic, pegmatitic, and contact metasomatic uranium deposits in igneous and metamorphic rocks. Production from these deposits have been insignificant (less than 0.08% of the total production from New Mexico), but there could be potential for medium to high-grade, medium-sized uranium deposits in some areas. Total uranium production from New Mexico from 1948 to 1987 amounts to approximately 341,808,000 lb of U 3 O 8 . New Mexico has significant uranium reserves and resources. Future development of these deposits will depend upon an increase in price for uranium and lowering of production costs, perhaps by in-situ leaching techniques

Uranium

International Nuclear Information System (INIS)

Hamdoun, N.A.

2007-01-01

The article includes a historical preface about uranium, discovery of portability of sequential fission of uranium, uranium existence, basic raw materials, secondary raw materials, uranium's physical and chemical properties, uranium extraction, nuclear fuel cycle, logistics and estimation of the amount of uranium reserves, producing countries of concentrated uranium oxides and percentage of the world's total production, civilian and military uses of uranium. The use of depleted uranium in the Gulf War, the Balkans and Iraq has caused political and environmental effects which are complex, raising problems and questions about the effects that nuclear compounds left on human health and environment.

Multistage charged particle accelerator, with high-vacuum insulation

International Nuclear Information System (INIS)

Holl, P.

1976-01-01

A multistage charged-particle accelerator for operating with accelerating voltages higher than 150 kV is described. The device consists essentially of a high-voltage insulator, a source for producing charged particles, a Wehnelt cylinder, an anode, and a post-accelerating tube containing stack-wise positioned post-accelerating electrodes. A high vacuum is used for insulating the parts carrying the high voltages, and at least one cylindrical screen surrounding these parts is interposed between them and the vacuum vessel, which can itself also function as a cylindrical screen

Conversion of the University of Missouri-Rolla Reactor from high-enriched uranium to low-enriched uranium fuel

International Nuclear Information System (INIS)

Bolon, A.E.; Straka, M.; Freeman, D.W.

1997-01-01

The objectives of this project were to convert the UMR Reactor fuel from high-enriched uranium (HEU) to low-enriched uranium (LEU) fuel and to ship the HEU fuel back to the Department of Energy Savannah River Site. The actual core conversion was completed in the summer of 1992. The HEU fuel was offloaded to an onsite storage pit where it remained until July, 1996. In July, 1996, the HEU fuel was shipped to the DOE Savannah River Site. The objectives of the project have been achieved. DOE provided the following funding for the project. Several papers were published regarding the conversion project and are listed in the Attachment. In retrospect, the conversion project required much more time and effort than originally thought. Several difficulties were encountered including the unavailability of a shipping cask for several years. The authors are grateful for the generous funding provided by DOE for this project but wish to point out that much of their efforts on the conversion project went unfunded

Comparison of solvent extraction and extraction chromatography resin techniques for uranium isotopic characterization in high-level radioactive waste and barrier materials.

Science.gov (United States)

Hurtado-Bermúdez, Santiago; Villa-Alfageme, María; Mas, José Luis; Alba, María Dolores

2018-07-01

The development of Deep Geological Repositories (DGP) to the storage of high-level radioactive waste (HLRW) is mainly focused in systems of multiple barriers based on the use of clays, and particularly bentonites, as natural and engineered barriers in nuclear waste isolation due to their remarkable properties. Due to the fact that uranium is the major component of HLRW, it is required to go in depth in the analysis of the chemistry of the reaction of this element within bentonites. The determination of uranium under the conditions of HLRW, including the analysis of silicate matrices before and after the uranium-bentonite reaction, was investigated. The performances of a state-of-the-art and widespread radiochemical method based on chromatographic UTEVA resins, and a well-known and traditional method based on solvent extraction with tri-n-butyl phosphate (TBP), for the analysis of uranium and thorium isotopes in solid matrices with high concentrations of uranium were analysed in detail. In the development of this comparison, both radiochemical approaches have an overall excellent performance in order to analyse uranium concentration in HLRW samples. However, due to the high uranium concentration in the samples, the chromatographic resin is not able to avoid completely the uranium contamination in the thorium fraction. Copyright © 2018 Elsevier Ltd. All rights reserved.

Spectrographic determination of lanthanides in high-purity uranium compounds, after chromatographic separation by alumina-hydrofluoric acid

International Nuclear Information System (INIS)

Lordello, A.R.; Abrao, A.

1979-01-01

A method is presented for the determination of fourteen rare earth elements in high-purity uranium compounds by emission spectrography. The rare earths are chromatographically separated from uranium by using alumina-hydrofluoric acid. Lanthanum is used both as collector and internal standard. The technique of excitation involves a total consumption of the sample in a 17 ampere direct current arc. The range of determination is about 0.005 to 0.5 μg/g uranium. The coefficient of variation for Pr, Ho, Dy, Er, Tm, Lu, Gd and Tb amounts to 10%. (Author) [pt

Continued Multicolumns Bioleaching for Low Grade Uranium Ore at a Certain Uranium Deposit

Directory of Open Access Journals (Sweden)

Gongxin Chen

2016-01-01

Full Text Available Bioleaching has lots of advantages compared with traditional heap leaching. In industry, bioleaching of uranium is still facing many problems such as site space, high cost of production, and limited industrial facilities. In this paper, a continued column bioleaching system has been established for leaching a certain uranium ore which contains high fluoride. The analysis of chemical composition of ore shows that the grade of uranium is 0.208%, which is lower than that of other deposits. However, the fluoride content (1.8% of weight is greater than that of other deposits. This can be toxic for bacteria growth in bioleaching progress. In our continued multicolumns bioleaching experiment, the uranium recovery (89.5% of 4th column is greater than those of other columns in 120 days, as well as the acid consumption (33.6 g/kg. These results indicate that continued multicolumns bioleaching technology is suitable for leaching this type of ore. The uranium concentration of PLS can be effectively improved, where uranium recovery can be enhanced by the iron exchange system. Furthermore, this continued multicolumns bioleaching system can effectively utilize the remaining acid of PLS, which can reduce the sulfuric acid consumption. The cost of production of uranium can be reduced and this benefits the environment too.

Design Study for a Low-Enriched Uranium Core for the High Flux Isotope Reactor, Annual Report for FY 2008

Energy Technology Data Exchange (ETDEWEB)

Primm, Trent [ORNL; Chandler, David [ORNL; Ilas, Germina [ORNL; Miller, James Henry [ORNL; Sease, John D [ORNL; Jolly, Brian C [ORNL

2009-03-01

This report documents progress made during FY 2008 in studies of converting the High Flux Isotope Reactor (HFIR) from highly enriched uranium (HEU) fuel to low-enriched uranium (LEU) fuel. Conversion from HEU to LEU will require a change in fuel form from uranium oxide to a uranium-molybdenum alloy. With axial and radial grading of the fuel foil and an increase in reactor power to 100 MW, calculations indicate that the HFIR can be operated with LEU fuel with no degradation in reactor performance from the current level. Results of selected benchmark studies imply that calculations of LEU performance are accurate. Scoping experiments with various manufacturing methods for forming the LEU alloy profile are presented.

Uranium extraction from gold-uranium ores

Energy Technology Data Exchange (ETDEWEB)

Laskorin, B.N.; Golynko, Z.Sh.

1981-01-01

The process of uranium extraction from gold-uranium ores in the South Africa is considered. Flowsheets of reprocessing gold-uranium conglomerates, pile processing and uranium extraction from the ores are presented. Continuous counter flow ion-exchange process of uranium extraction using strong-active or weak-active resins is noted to be the most perspective and economical one. The ion-exchange uranium separation with the succeeding extraction is also the perspective one.

A confirmatory measurement technique for highly enriched uranium

International Nuclear Information System (INIS)

Sprinkle, J.K. Jr.

1987-07-01

This report describes a confirmatory measurement technique for measuring uranium items in their shipping containers. The measurement consists of a weight verification and the detection of three gamma rays. The weight can be determined very precisely, thus it severely constrains the options of the diverter who might want to imitate the gamma signal with a bogus item. The 185.7-keV gamma ray originates from 235 U, the 1001 keV originates from a daughter of 238 U, and the 2614 keV originates from a daughter of 232 U. These three gamma rays exhibit widely different attenuation properties, they correlate with enrichment and total uranium mass, and they rigorously discriminate against a likely diversion scenario (low-enriched uranium substitution). These four measured quantities, when combined, provide a signature that is very difficult to counterfeit

Method for converting uranium oxides to uranium metal

International Nuclear Information System (INIS)

Duerksen, W.K.

1988-01-01

A method for converting uranium oxide to uranium metal is described comprising the steps of heating uranium oxide in the presence of a reducing agent to a temperature sufficient to reduce the uranium oxide to uranium metal and form a heterogeneous mixture of a uranium metal product and oxide by-products, heating the mixture in a hydrogen atmosphere at a temperature sufficient to convert uranium metal in the mixture to uranium hydride, cooling the resulting uranium hydride-containing mixture to a temperature sufficient to produce a ferromagnetic transition in the uranium hydride, magnetically separating the cooled uranium hydride from the mixture, and thereafter heating the separated uranium hydride in an inert atmosphere to a temperature sufficient to convert the uranium hydride to uranium metal

Experimental investigation on the use of highly charged nanoparticles to improve the stability of weakly charged colloidal system.

Science.gov (United States)

Zubir, Mohd Nashrul Mohd; Badarudin, A; Kazi, S N; Misran, Misni; Amiri, Ahmad; Sadri, Rad; Khalid, Solangi

2015-09-15

The present work highlighted on the implementation of a unique concept for stabilizing colloids at their incipiently low charge potential. A highly charged nanoparticle was introduced within a coagulated prone colloidal system, serving as stabilizer to resist otherwise rapid flocculation and sedimentation process. A low size asymmetry of nanoparticle/colloid serves as the new topic of investigation in addition to the well-established large size ratio nanoparticle/microparticle study. Highly charged Al2O3 nanoparticles were used within the present research context to stabilize TiO2 and Fe3O4 based colloids via the formation of composite structures. It was believed, based on the experimental evidence, that Al2O3 nanoparticle interact with the weakly charged TiO2 and Fe3O4 colloids within the binary system via absorption and/or haloing modes to increase the overall charge potential of the respective colloids, thus preventing further surface contact via van der Waal's attraction. Series of experimental results strongly suggest the presence of weakly charged colloids in the studied bimodal system where, in the absence of highly charged nanoparticle, experience rapid instability. Absorbance measurement indicated that the colloidal stability drops in accordance to the highly charged nanoparticle sedimentation rate, suggesting the dominant influence of nanoparticles to attain a well-dispersed binary system. Further, it was found that the level of colloidal stability was enhanced with increasing nanoparticle fraction within the mixture. Rheological observation revealed that each hybrid complexes demonstrated behavior reminiscence to water with negligible increase in viscosity which serves as highly favorable condition particularly in thermal transport applications. Copyright © 2015 Elsevier Inc. All rights reserved.

High-resolution x-ray scattering studies of charge ordering in highly correlated electron systems

International Nuclear Information System (INIS)

Ghazi, M.E.

2002-01-01

Many important properties of transition metal oxides such as, copper oxide high-temperature superconductivity and colossal magnetoresistance (CMR) in manganites are due to strong electron-electron interactions, and hence these systems are called highly correlated systems. These materials are characterised by the coexistence of different kinds of order, including charge, orbital, and magnetic moment. This thesis contains high-resolution X-ray scattering studies of charge ordering in such systems namely the high-T C copper oxides isostructural system, La 2-x Sr x NiO 4 with various Sr concentrations (x = 0.33 - 0.2), and the CMR manganite system, Nd 1/2 Sr 1/2 MnO 3 . It also includes a review of charge ordering in a large variety of transition metal oxides, such as ferrates, vanadates, cobaltates, nickelates, manganites, and cuprates systems, which have been reported to date in the scientific literature. Using high-resolution synchrotron X-ray scattering, it has been demonstrated that the charge stripes exist in a series of single crystals of La 2-x Sr x NiO 4 with Sr concentrations (x = 0.33 - 0.2) at low temperatures. Satellite reflections due to the charge ordering were found with the wavevector (2ε, 0, 1) below the charge ordering transition temperature, T CO , where 2ε is the amount of separation from the corresponding Bragg peak. The charge stripes are shown to be two-dimensional in nature both by measurements of their correlation lengths and by measurement of the critical exponents of the charge stripe melting transition with an anomaly at x = 0.25. The results show by decreasing the hole concentration from the x = 0.33 to 0.2, the well-correlated charge stripes change to a glassy state at x = 0.25. The electronic transition into the charge stripe phase is second-order without any corresponding structural transition. Above the second-order transition critical scattering was observed due to fluctuations into the charge stripe phase. In a single-crystal of Nd

Using depleted uranium to shield vitrified high-level waste packages

International Nuclear Information System (INIS)

Yoshimura, H.R.; Gildea, P.D.; Bernard, E.A.

1995-01-01

The underlying report for this paper evaluates options for using depleted uranium as shielding materials for transport systems for disposal of vitrified high-level waste (VHLW). In addition, economic analyses are presented to compare costs associated with these options to costs, associated with existing and proposed storage, transport, and diposal capabilities. A more detailed evaluation is provided elsewhere. (Yoshimura et al. 1995.)

Determination of uranium and plutonium in high active solutions by extractive spectrophotometry

International Nuclear Information System (INIS)

Subba Rao, R.V.; Damodaran, K.; Santosh Kumar, G.; Ravi, T.N.

2000-01-01

Plutonium and uranium was extracted from nitric acid into trioctyl phosphine oxide in xylene. The TOPO layer was analysed by spectrophotometry. Thoron was used as the chromogenic agent for plutonium. Pyridyl azoresorcinol was used as chromogenic agent for uranium. The molar absorption coefficient for uranium and plutonium was found to be 19000 and 19264 liter/mole-cm, respectively. The correlation coefficient for plutonium and uranium was found to be 0.9994. The relative standard deviation for the determination of plutonium and uranium was found to be 0.96% and 1.4%, respectively. (author)

Uranium recovery from phosphate fertilizer in the form of a high purity compound

International Nuclear Information System (INIS)

Bunus, F.; Coroianu, T.; Filip, G.; Filip, D.

2001-01-01

Uranium recovery from phosphate fertilizer industry is based on a one cycle extraction-stripping process. The process was experimented on both sulfuric and nitric acid attack of phosphate rock when uranium is dissolved in phosphoric acid (WPA) or phosphonitric (PN) solution respectively. The WPA and PN solution must be clarified. In the first alternative by ageing and settling and in the second by settling in the presence of flocculant. The organic components must be removed on active carbon for WPA only since in the case of nitric attack calcined phosphates are used. In both alternatives uranium is extracted from aqueous acidic solutions in the same time with the rare earths (REE), by di(2-ethylhexyl) phosphate (DEPA) as basic extractants, eventually in the presence of octylphosphine oxide (TOPO) as synergic agent. The stripping process is carried out in two stages: in the first stage REE are stripped and precipitated by HF or NH 4 F + H 2 S0 4 and in the second stage uranium as U(VI) is stripped by the same reagents but in the presence of Fe(II) as reductant for U(VI) to U(IV) inextractible species. Tetravalent uranium is also precipitated as green cake either UF 4 xH 2 0 or (NH 4 ) 7 U 6 F 31 as dependent on reagents HF or NH 4 F + H 2 S0 4 . Uranium stripping is possible for PN solution only if HNO 3 partially extracted is previously washed out by a urea solution. The green cake washed and filtered is dissolved in nitric acid in presence of Al(OH)3 as complexant for F. The filtered nitric solution is adjusted to 3-5 mol/L HNO 3 and extracted by 20% TBP when uranium is transferred to the organic phase which after scrubbing is stripped in the classic way with acidulated (HN0 3 ) demineralized water. Uranium is precipitated as diuranate of high purity. Rare earths left in the aqueous raffinate are extracted by pure TBP from 8-10 mol/L HNO 3 medium. The stripping process takes place with acidulated water. Rare earths are precipitated as hydroxides. (author)

Comparison of laser fluorimetry, high resolution gamma-ray spectrometry and neutron activation analysis techniques for determination of uranium content in soil samples

International Nuclear Information System (INIS)

Ghods, A.; Asgharizadeh, F.; Salimi, B.; Abbasi, A.

2004-01-01

Much more concern is given nowadays for exposure of the world population to natural radiation especially to uranium since 57% of that exposure is due to radon-222, which is a member of uranium decay series. Most of the methods used for uranium determination is low concentration require either tedious separation and preconcentration or the accessibility to special instrumentation for detection of uranium at this low level. this study compares three techniques and methods for uranium analysis among different soil sample with variable uranium contents. Two of these techniques, neutron activation analysis and high resolution gamma-ray spectrometry , are non-destructive while the other, laser fluorimetry is done via chemical extraction of uranium. Analysis of standard materials is done also to control the quality and accuracy of the work. In spite of having quite variable ranges of detection limit, results obtained by high resolution gamma-ray spectrometry based on the assumption of having secular equilibrium between uranium and its daughters, which causes deviation whenever this condition was missed. For samples with reasonable uranium content, neutron activation analysis would be a rapid and reliable technique, while for low uranium content laser fluorimetry would be the most appropriate and accurate technique

Dry uranium tetrafluoride process preparation using the uranium hexafluoride reconversion process effluents

International Nuclear Information System (INIS)

Silva Neto, Joao Batista da

2008-01-01

It is a well known fact that the use of uranium tetrafluoride allows flexibility in the production of uranium suicide and uranium oxide fuel. To its obtention there are two conventional routes, the one which reduces uranium from the UF 6 hydrolysis solution with stannous chloride, and the hydro fluorination of a solid uranium dioxide. In this work we are introducing a third and a dry way route, mainly utilized to the recovery of uranium from the liquid effluents generated in the uranium hexafluoride reconversion process, at IPEN/CNEN-SP. Working in the liquid phase, this route comprises the recuperation of ammonium fluoride by NH 4 HF 2 precipitation. Working with the solid residues, the crystallized bifluoride is added to the solid UO 2 , which comes from the U mini plates recovery, also to its conversion in a solid state reaction, to obtain UF 4 . That returns to the process of metallic uranium production unity to the U 3 Si 2 obtention. This fuel is considered in IPEN CNEN/SP as the high density fuel phase for IEA-R1m reactor, which will replace the former low density U 3 Si 2 -Al fuel. (author)

Price of military uranium

International Nuclear Information System (INIS)

Klimenko, A.V.

1998-01-01

The theoretical results about optimum strategy of use of military uranium confirmed by systems approach accounts are received. The numerical value of the system approach price of the highly enriched military uranium also is given

Concept for high-charge-state ion induction accelerators

International Nuclear Information System (INIS)

Logan, B.G.; Perry, M.D.; Caporaso, G.J.

1996-01-01

This work describes a particular concept for ion induction linac accelerators using high-charge-state ions produced by an intense, short pulse laser, and compares the costs of a modular driver system producing 6.5 MJ for a variety of ion masses and charge states using a simple but consistent cost model

Conversion and Blending Facility highly enriched uranium to low enriched uranium as metal. Revision 1

Energy Technology Data Exchange (ETDEWEB)

NONE

1995-07-05

The mission of this Conversion and Blending Facility (CBF) will be to blend surplus HEU metal and alloy with depleted uranium metal to produce an LEU product. The primary emphasis of this blending operation will be to destroy the weapons capability of large, surplus stockpiles of HEU. The blended LEU product can only be made weapons capable again by the uranium enrichment process. The blended LEU will be produced as a waste suitable for storage or disposal.

Conversion and Blending Facility highly enriched uranium to low enriched uranium as metal. Revision 1

International Nuclear Information System (INIS)

1995-01-01

The mission of this Conversion and Blending Facility (CBF) will be to blend surplus HEU metal and alloy with depleted uranium metal to produce an LEU product. The primary emphasis of this blending operation will be to destroy the weapons capability of large, surplus stockpiles of HEU. The blended LEU product can only be made weapons capable again by the uranium enrichment process. The blended LEU will be produced as a waste suitable for storage or disposal

Development of high uranium-density fuels for use in research reactors

International Nuclear Information System (INIS)

Ugajin, Mitsuhiro; Akabori, Mitsuo; Itoh, Akinori

1996-01-01

The uranium silicide U 3 Si 2 possesses uranium density 11.3 gU/cm 3 with a congruent melting point of 1665degC, and is now successfully in use as a research reactor fuel. Another uranium silicide U 3 Si and U 6 Me-type uranium alloys (Me=Fe,Mn,Ni) have been chosen as new fuel materials because of the higher uranium densities 14.9 and 17.0 gU/cm 3 , respectively. Experiments were carried out to fabricate miniature aluminum-dispersion plate-type and aluminum-clad disk-type fuels by using the conventional picture-frame method and a hot-pressing technique, respectively. These included the above-mentioned new fuel materials as well as U 3 Si 2 . Totally 14 miniplates with uranium densities from 4.0 to 6.3 gU/cm 3 of fuel meat were prepared together with 28 disk-type fuel containing structurally-modified U 3 Si, and subjected to the neutron irradiation in JMTR (Japan Materials Testing Reactor). Some results of postirradiation examinations are presented. (author)

How much of the rocks and the oceans for power? Exploiting the uranium-thorium fission cycle

International Nuclear Information System (INIS)

Lewis, W.B.

1964-04-01

Even at quite low costs there appear to be many routes available to supply the world population of the future with its power for electricity, heat, energy storage, portable fuel, desalting water and local climate control. For example, sufficient power could come from nuclear fission in thermal neutron reactors. When rich uranium ores have become scarce, the price will rise from the current $13/kg U, but with improved techniques of extraction and the choice of an economical fuel cycle, abundant uranium for many centuries appears to be available in the rocks and the oceans. Even from reactors already developed to the stage of engineering design it is possible to choose a fuel cycle to which uranium at $250/kg U would contribute no more than 2 mill/kWh. Without suggesting when such a high cost might he reached, its implications are examined. The optimum fuel cycle would balance the financing charges on the fuel inventory and the costs of fuel make-up supply and reprocessing. By using uranium and thorium in combination at least 50,000 MWd can be derived per tonne of uranium. At a current low net conversion efficiency of 30% and an overall rating of 6 thermal kW/kg, the natural uranium inventory would cost at the suggested high price $250/(6 x 0.3) $139/ekW and for 7000 hr/yr at 7% annual charges would contribute 1.4 mill/ekWh. At 50 MWd/kg U the make-up supply contributes 250/(50 x 24 x 0.3) = 0.7 mill/ekWh. Probably higher efficiency and possibly higher specific power ratings would be used to lower such costs. The value of uranium is related to its content of the fissile U-235, and even though most power may be derived from thorium, its value will not rise comparably with that of uranium. In the course of time a ceiling will be set on the value of fissile material by the introduction of processes other than the thermal neutron fission chain reaction for producing power or neutrons. The total cost of nuclear power includes also contributions from the cost of equipment

How much of the rocks and the oceans for power? Exploiting the uranium-thorium fission cycle

Energy Technology Data Exchange (ETDEWEB)

Lewis, W B

1964-04-15

Even at quite low costs there appear to be many routes available to supply the world population of the future with its power for electricity, heat, energy storage, portable fuel, desalting water and local climate control. For example, sufficient power could come from nuclear fission in thermal neutron reactors. When rich uranium ores have become scarce, the price will rise from the current $13/kg U, but with improved techniques of extraction and the choice of an economical fuel cycle, abundant uranium for many centuries appears to be available in the rocks and the oceans. Even from reactors already developed to the stage of engineering design it is possible to choose a fuel cycle to which uranium at $250/kg U would contribute no more than 2 mill/kWh. Without suggesting when such a high cost might be reached, its implications are examined. The optimum fuel cycle would balance the financing charges on the fuel inventory and the costs of fuel make-up supply and reprocessing. By using uranium and thorium in combination at least 50,000 MWd can be derived per tonne of uranium. At a current low net conversion efficiency of 30% and an overall rating of 6 thermal kW/kg, the natural uranium inventory would cost at the suggested high price $250/(6 x 0.3) $139/ekW and for 7000 hr/yr at 7% annual charges would contribute 1.4 mill/ekWh. At 50 MWd/kg U the make-up supply contributes 250/(50 x 24 x 0.3) = 0.7 mill/ekWh. Probably higher efficiency and possibly higher specific power ratings would be used to lower such costs. The value of uranium is related to its content of the fissile U-235, and even though most power may be derived from thorium, its value will not rise comparably with that of uranium. In the course of time a ceiling will be set on the value of fissile material by the introduction of processes other than the thermal neutron fission chain reaction for producing power or neutrons. The total cost of nuclear power includes also contributions from the cost of equipment

Selective Removal of Uranium from the Washing Solution of Uranium-Contaminated Soil

Energy Technology Data Exchange (ETDEWEB)

Kim, Seung Soo; Han, G. S.; Kim, G. N.; Koo, D. S.; Jeong, J. W.; Choi, J. W. [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2015-10-15

This study examined selective removal methods of uranium from the waste solution by ion exchange resins or solvent extraction methods to reduce amount of the 2{sup nd} waste. Alamine-336, known as an excellent extraction reagent of uranium from the leaching solution of uranium ore, did not remove uranium from the acidic washing solution of soil. Uranyl ions in the acidic waste solution were sorbed on ampholyte resin with a high sorption efficiency, and desorbed from the resin by a washing with 0.5 M Na{sub 2}CO{sub 3} solution at 60 .deg. C. However, the uranium dissolved in the sulfuric acid solution was not sorbed onto the strong anion exchanger resins. A great amount of uranium-contaminated (U-contaminated) soil had been generated from the decommissioning of a uranium conversion plant. Our group has developed a decontamination process with washing and electrokinetic methods to decrease the amount of waste to be disposed of. However, this process generates a large amount of waste solution containing various metal ions.

Position paper Oak Ridge Y-12 Plant storage of uranium in plastics

International Nuclear Information System (INIS)

Duerksen, W.K.

1995-07-01

As a result of the end of the Cold War, the United States nuclear weapon stockpile is being reduced from approximately 20,000 warheads to fewer than 10,000 by the end of the century. The Oak Ridge Y-12 Plant is the Department of Energy (DOE) site charged with the responsibility of providing safe, secure storage for the uranium recovered from these weapons. In addition to weapons material, Y-12 has traditionally processed and stored uranium from nonweapon programs and presumably will continue to do so. The purpose of this document is to evaluate the suitability of plastics for use in the containment of uranium

Method for converting uranium oxides to uranium metal

Science.gov (United States)

Duerksen, Walter K.

1988-01-01

A process is described for converting scrap and waste uranium oxide to uranium metal. The uranium oxide is sequentially reduced with a suitable reducing agent to a mixture of uranium metal and oxide products. The uranium metal is then converted to uranium hydride and the uranium hydride-containing mixture is then cooled to a temperature less than -100.degree. C. in an inert liquid which renders the uranium hydride ferromagnetic. The uranium hydride is then magnetically separated from the cooled mixture. The separated uranium hydride is readily converted to uranium metal by heating in an inert atmosphere. This process is environmentally acceptable and eliminates the use of hydrogen fluoride as well as the explosive conditions encountered in the previously employed bomb-reduction processes utilized for converting uranium oxides to uranium metal.

Emission of light charged particles from fragments produced on fission of uranium nuclei by 153 MeV protons and 1700 MeV negative pions

International Nuclear Information System (INIS)

Belovitzky, G.E.; Shteingrad, O.M.

2000-01-01

The mechanism underlying the emission of light charged particles (LCP) with Z = 1, 2 from fragments produced in fission of uranium nuclei by 153 MeV protons and 1700 MeV negative pions was studied. It was found that LCP accompanying the fission by pions are emitted from non-accelerated fragments immediately after the fission, whereas in the case of 153 MeV protons, the LCP are emitted from the accelerated heavy fragments. The number of LCP emitted in the course of pion-induced fission is 0.7 per fission event, which exceeds by a factor of 30 the corresponding number for 153 MeV protons [ru

Highly Enriched Uranium Metal Cylinders Surrounded by Various Reflector Materials

International Nuclear Information System (INIS)

Bernard Jones; J. Blair Briggs; Leland Monteirth

2007-01-01

A series of experiments was performed at Los Alamos Scientific Laboratory in 1958 to determine critical masses of cylinders of Oralloy (Oy) reflected by a number of materials. The experiments were all performed on the Comet Universal Critical Assembly Machine, and consisted of discs of highly enriched uranium (93.3 wt.% 235U) reflected by half-inch and one-inch-thick cylindrical shells of various reflector materials. The experiments were performed by members of Group N-2, particularly K. W. Gallup, G. E. Hansen, H. C. Paxton, and R. H. White. This experiment was intended to ascertain critical masses for criticality safety purposes, as well as to compare neutron transport cross sections to those obtained from danger coefficient measurements with the Topsy Oralloy-Tuballoy reflected and Godiva unreflected critical assemblies. The reflector materials examined in this series of experiments are as follows: magnesium, titanium, aluminum, graphite, mild steel, nickel, copper, cobalt, molybdenum, natural uranium, tungsten, beryllium, aluminum oxide, molybdenum carbide, and polythene (polyethylene). Also included are two special configurations of composite beryllium and iron reflectors. Analyses were performed in which uncertainty associated with six different parameters was evaluated; namely, extrapolation to the uranium critical mass, uranium density, 235U enrichment, reflector density, reflector thickness, and reflector impurities. In addition to the idealizations made by the experimenters (removal of the platen and diaphragm), two simplifications were also made to the benchmark models that resulted in a small bias and additional uncertainty. First of all, since impurities in core and reflector materials are only estimated, they are not included in the benchmark models. Secondly, the room, support structure, and other possible surrounding equipment were not included in the model. Bias values that result from these two simplifications were determined and associated

Electron capture by highly charged low-velocity ions

International Nuclear Information System (INIS)

Cocke, C.L.; Dubois, R.; Justiniano, E.; Gray, T.J.; Can, C.

1982-01-01

This paper describes the use of a fast heavy ion beam to produce, by bombardment of gaseous targets, highly-charged low-velocity recoil ions, and the use of these secondary ions in turn as projectiles in studies of electron capture and ionization in low-energy collision systems. The interest in collisions involving low-energy highly-charged projectiles comes both from the somewhat simplifying aspects of the physics which attend the long-range capture and from applications to fusion plasmas, astrophysics and more speculative technology such as the production of X-ray lasers. The ions of interest in such applications should have both electronic excitation and center-of-mass energies in the keV range and cannot be produced by simply stripping fast heavy ion beams. Several novel types of ion source have been developed to produce low-energy highly-charged ions, of which the secondary ion recoil source discussed in this paper is one. (Auth.)

Carbonate heap leach of uranium-contaminated soils

International Nuclear Information System (INIS)

Turney, W.R.; Mason, C.F.V.; Longmire, P.

1994-01-01

A new approach to removal of uranium from soils based on existing heap leach mining technologies proved highly effective for remediation of soils from the Fernald Environmental Management Project (FEMP) near Cincinnati, Ohio. In laboratory tests, remediation of uranium-contaminated soils by heap leaching with carbonate salt solutions was demonstrated in column experiments. An understanding of the chemical processes that occur during carbonate leach of uranium from soils may lead to enhancement of uranium removal. Carbonate leaching requires the use of an integrated and closed circuit process, wherein the leach solutions are recycled and the reagents are reused, resulting in a minimum secondary waste stream. Carbonate salt leach solution has two important roles. Primarily, the formation of highly soluble anionic carbonate uranyl species, including uranyl dicarbonate (UO 2 CO 32 = ) and uranyl tricarbonate (UO 2 CO 33 4- ), allows for high concentration of uranium in a leachate solution. Secondly, carbonate salts are nearly selective for dissolution of uranium from uranium contaminated soils. Other advantages of the carbonate leaching process include (1) the high solubility, (2) the selectivity, (3) the purity of the solution produced, (4) the relative ease with which a uranium product can be precipitated directly from the leachate solution, and (5) the relatively non-corrosive and safe handling characteristics of carbonate solutions. Experiments conducted in the laboratory have demonstrated the effectiveness of carbonate leach. Efficiencies of uranium removal from the soils have been as high as 92 percent. Higher molar strength carbonate solutions (∼0.5M) proved more effective than lower molar strength solutions (∼ 0.1M). Uranium removal is also a function of lixiviant loading rate. Furthermore, agglomeration of the soils with cement resulted in less effective uranium removal

DESIGN STUDY FOR A LOW-ENRICHED URANIUM CORE FOR THE HIGH FLUX ISOTOPE REACTOR, ANNUAL REPORT FOR FY 2010

Energy Technology Data Exchange (ETDEWEB)

Cook, David Howard [ORNL; Freels, James D [ORNL; Ilas, Germina [ORNL; Jolly, Brian C [ORNL; Miller, James Henry [ORNL; Primm, Trent [ORNL; Renfro, David G [ORNL; Sease, John D [ORNL; Pinkston, Daniel [ORNL

2011-02-01

This report documents progress made during FY 2010 in studies of converting the High Flux Isotope Reactor (HFIR) from high enriched uranium (HEU) fuel to low enriched uranium (LEU) fuel. Conversion from HEU to LEU will require a change in fuel form from uranium oxide to a uranium-molybdenum alloy. With axial and radial grading of the fuel foil and an increase in reactor power to 100 MW, calculations indicate that the HFIR can be operated with LEU fuel with no degradation in performance to users from the current level. Studies are reported of support to a thermal hydraulic test loop design, the implementation of finite element, thermal hydraulic analysis capability, and infrastructure tasks at HFIR to upgrade the facility for operation at 100 MW. A discussion of difficulties with preparing a fuel specification for the uranium-molybdenum alloy is provided. Continuing development in the definition of the fuel fabrication process is described.

Display of charged ionizing particles

International Nuclear Information System (INIS)

Cano S, D.; Ortiz A, M. D.; Amarillas S, L. E.; Vega C, H. R.

2017-10-01

The human being is exposed to sources of ionizing and non-ionizing radiation, both of natural or anthropogenic origin. None of these, except non-ionizing such as visible light and infrared radiation, can be detected by the sense of sight and touch respectively. The sun emits charged particles with speeds close to the light that interact with the atoms of the gases present in the atmosphere, producing nuclear reactions that in turn produce other particles that reach the surface of the Earth and reach the living beings. On Earth there are natural radioisotopes that, when they disintegrate, emit ionizing radiation that contributes to the dose we receive. A very old system that allows the visualization of the trajectories of the charged ionizing particles is the Fog Chamber that uses a saturated steam that when crossed by particles with mass and charge, as alpha and beta particles produce condensation centers along its path leaves a trace that can be seen. The objective of this work was to build a fog chamber using easily accessible materials. To measure the functioning of the fog chamber, cosmic rays were measured, as well as a source of natural metal uranium. The fog chamber allowed seeing the presence of traces in alcohol vapor that are produced in a random way. Introducing the uranium foil inside the fog chamber, traces of alpha particles whose energy varies from 4 to 5 MeV were observed. (Author)

Post-mining water treatment. Nanofiltration of uranium-contaminated drainage. Experiments and modeling

Energy Technology Data Exchange (ETDEWEB)

Hoyer, Michael

2017-07-01

Nanofiltration of real uranium-contaminated mine drainage was successfully discussed in experiments and modeling. For the simulation a renowned model was adapted that is capable of describing multi-component solutions. Although the description of synthetic multi-component solutions with a limited number of components was performed before ([Garcia-Aleman2004], [Geraldes2006], [Bandini2003]) the results of this work show that the adapted model is capable of describing the very complex solution. The model developed here is based on: The Donnan-Steric Partitioning Pore Model incorporating Dielectric Exclusion - DSPM and DE ref. [Bowen1997], [Bandini2003], [Bowen2002], [Vezzani2002]. The steric, electric, and dielectric exclusion model - SEDE ref. [Szymczyk2005]. The developed modeling approach is capable of describing multi-component transport, and is based on the pore radius, membrane thickness, and volumetric membrane charge density as physically relevant membrane parameters instead of mere fitting parameters which allows conclusions concerning membrane modification or process design. The experiments involve typical commercially available membranes in combination with a water sample of industrial relevance in the mining sector. Furthermore, it has been shown experimentally that uranium speciation influences its retention. Hence, all experiments consider the speciation of uranium when assessing its charge and size. In the simulation 10 different ionic components have been taken into account. By freely fitting 4 parameters in parallel (pore radius, membrane thickness, membrane charge, relative permittivity of the oriented water layer at the pore wall) an excellent agreement between experiment and simulation was obtained. Moreover, the determined membrane thickness and pore radius is in close agreement with the values obtained by independent membrane characterization using pure water permeability and glucose retention. On the other hand, the fitted and the literature

Post-mining water treatment. Nanofiltration of uranium-contaminated drainage. Experiments and modeling

International Nuclear Information System (INIS)

Hoyer, Michael

2017-01-01

Nanofiltration of real uranium-contaminated mine drainage was successfully discussed in experiments and modeling. For the simulation a renowned model was adapted that is capable of describing multi-component solutions. Although the description of synthetic multi-component solutions with a limited number of components was performed before ([Garcia-Aleman2004], [Geraldes2006], [Bandini2003]) the results of this work show that the adapted model is capable of describing the very complex solution. The model developed here is based on: The Donnan-Steric Partitioning Pore Model incorporating Dielectric Exclusion - DSPM and DE ref. [Bowen1997], [Bandini2003], [Bowen2002], [Vezzani2002]. The steric, electric, and dielectric exclusion model - SEDE ref. [Szymczyk2005]. The developed modeling approach is capable of describing multi-component transport, and is based on the pore radius, membrane thickness, and volumetric membrane charge density as physically relevant membrane parameters instead of mere fitting parameters which allows conclusions concerning membrane modification or process design. The experiments involve typical commercially available membranes in combination with a water sample of industrial relevance in the mining sector. Furthermore, it has been shown experimentally that uranium speciation influences its retention. Hence, all experiments consider the speciation of uranium when assessing its charge and size. In the simulation 10 different ionic components have been taken into account. By freely fitting 4 parameters in parallel (pore radius, membrane thickness, membrane charge, relative permittivity of the oriented water layer at the pore wall) an excellent agreement between experiment and simulation was obtained. Moreover, the determined membrane thickness and pore radius is in close agreement with the values obtained by independent membrane characterization using pure water permeability and glucose retention. On the other hand, the fitted and the literature

Recovery of uranium from the Syrian phosphate by solid-liquid method using alkaline solutions

International Nuclear Information System (INIS)

Shlewit, H.; Alibrahim, M.

2007-01-01

Uranium concentrations were analyzed in the Syrian phosphate deposits. Mean concentrations were found between 50 and 110 ppm. As a consequence, an average phosphate dressing of 22 kg/ha phosphate would charge the soil with 5-20 g/ha uranium when added as a mineral fertilizer. Fine grinding phosphate produced at the Syrian mines was used for uranium recovery by carbonate leaching. The formation of the soluble uranyl tricarbonate anion UO 2 (CO 3 ) 3 4- permits use of alkali solutions of sodium carbonate and sodium bicarbonate salts for the nearly selective dissolution of uranium from phosphate. Separation of iron, aluminum, titanium, etc., from the uranium during leaching was carried out. Formation of some small amounts of molybdates, vanadates, phosphates, aluminates, and some complexes metal was investigated. This process could be used before the manufacture of TSP fertilizer, and the final products would contain smaller uranium quantities. (author)

Use of Savannah River Site facilities for blend down of highly enriched uranium

International Nuclear Information System (INIS)

Bickford, W.E.; McKibben, J.M.

1994-02-01

Westinghouse Savannah River Company was asked to assess the use of existing Savannah River Site (SRS) facilities for the conversion of highly enriched uranium (HEU) to low enriched uranium (LEU). The purpose was to eliminate the weapons potential for such material. Blending HEU with existing supplies of depleted uranium (DU) would produce material with less than 5% U-235 content for use in commercial nuclear reactors. The request indicated that as much as 500 to 1,000 MT of HEU would be available for conversion over a 20-year period. Existing facilities at the SRS are capable of producing LEU in the form of uranium trioxide (UO 3 ) powder, uranyl nitrate [UO 2 (NO 3 ) 2 ] solution, or metal. Additional processing, and additional facilities, would be required to convert the LEU to uranium dioxide (UO 2 ) or uranium hexafluoride (UF 3 ), the normal inputs for commercial fuel fabrication. This study's scope does not include the cost for new conversion facilities. However, the low estimated cost per kilogram of blending HEU to LEU in SRS facilities indicates that even with fees for any additional conversion to UO 2 or UF 6 , blend-down would still provide a product significantly below the spot market price for LEU from traditional enrichment services. The body of the report develops a number of possible facility/process combinations for SRS. The primary conclusion of this study is that SRS has facilities available that are capable of satisfying the goals of a national program to blend HEU to below 5% U-235. This preliminary assessment concludes that several facility/process options appear cost-effective. Finally, SRS is a secure DOE site with all requisite security and safeguard programs, personnel skills, nuclear criticality safety controls, accountability programs, and supporting infrastructure to handle large quantities of special nuclear materials (SNM)

Uranium

International Nuclear Information System (INIS)

Cuney, M.; Pagel, M.; Leroy, J.

1992-01-01

First, this book presents the physico-chemical properties of Uranium and the consequences which can be deduced from the study of numerous geological process. The authors describe natural distribution of Uranium at different scales and on different supports, and main Uranium minerals. A great place in the book is assigned to description and classification of uranium deposits. The book gives also notions on prospection and exploitation of uranium deposits. Historical aspects of Uranium economical development (Uranium resources, production, supply and demand, operating costs) are given in the last chapter. 7 refs., 17 figs

The design on high slope stabilization in waste rock sites of uranium mines

International Nuclear Information System (INIS)

Liu Taoan; Zhou Xinghuo; Liu Jia

2005-01-01

Design methods, reinforcement measures, and flood control measures concerning high slope stabilization in harnessing waste rock site are described in brief according to some examples of two uranium mines in Hunan province. (authors)

Uranium

International Nuclear Information System (INIS)

Poty, B.; Cuney, M.; Bruneton, P.; Virlogeux, D.; Capus, G.

2010-01-01

With the worldwide revival of nuclear energy comes the question of uranium reserves. For more than 20 years, nuclear energy has been neglected and uranium prospecting has been practically abandoned. Therefore, present day production covers only 70% of needs and stocks are decreasing. Production is to double by 2030 which represents a huge industrial challenge. The FBR-type reactors technology, which allows to consume the whole uranium content of the fuel, is developing in several countries and will ensure the long-term development of nuclear fission. However, the implementation of these reactors (the generation 4) will be progressive during the second half of the 21. century. For this reason an active search for uranium ores will be necessary during the whole 21. century to ensure the fueling of light water reactors which are huge uranium consumers. This dossier covers all the aspects of natural uranium production: mineralogy, geochemistry, types of deposits, world distribution of deposits with a particular attention given to French deposits, the exploitation of which is abandoned today. Finally, exploitation, ore processing and the economical aspects are presented. Contents: 1 - the uranium element and its minerals: from uranium discovery to its industrial utilization, the main uranium minerals (minerals with tetravalent uranium, minerals with hexavalent uranium); 2 - uranium in the Earth's crust and its geochemical properties: distribution (in sedimentary rocks, in magmatic rocks, in metamorphic rocks, in soils and vegetation), geochemistry (uranium solubility and valence in magmas, uranium speciation in aqueous solution, solubility of the main uranium minerals in aqueous solution, uranium mobilization and precipitation); 3 - geology of the main types of uranium deposits: economical criteria for a deposit, structural diversity of deposits, classification, world distribution of deposits, distribution of deposits with time, superficial deposits, uranium

Recovery of uranium from seawater

International Nuclear Information System (INIS)

Hirotsu, Takahiro; Takagi, Norio; Katoh, Shunsaku

1995-01-01

Present status of the development of chelating adsorbents for the recovery of uranium from seawater is outlined with emphasis on the research by the author. Uranium is estimated to exist as stable tri (carbonate) uranylate (6) ion in seawater in a very low concentration. The adsorbent for uranium from seawater in a very low concentration. The adsorbent for uranium from seawater should have high selectivity and affinity for uranium around pH 8. The required characteristics for uranium adsorbent are examined. Various chelating adsorbents have been proposed for the uranium adsorbent and their structures are discussed. Amidoxime type adsorbents have the highest adsorbing power for uranium among the adsorbents hitherto developed and fibrous amidoxime adsorbents are most promising for the practical application. Synthesis, structure and suitable shape of the amidoxime adsorbents are discussed. Uranium adsorption behavior and the amount of saturated adsorption are examined theoretically based on the complexation of an amidoxime monomer and the formula for the adsorption equiliburium is derived. The adsorption and recovery process for uranium from seawater is composed of adsorption, desorption, separation and concentration and finally, uranium is recovered as the yellow cake. A floating body mooring system is proposed by Nobukawa. (T.H.)

Method of semi-automatic high precision potentiometric titration for characterization of uranium compounds

International Nuclear Information System (INIS)

Cristiano, Barbara Fernandes G.; Dias, Fabio C.; Barros, Pedro D. de; Araujo, Radier Mario S. de; Delgado, Jose Ubiratan; Silva, Jose Wanderley S. da; Lopes, Ricardo T.

2011-01-01

The method of high precision potentiometric titration is widely used in the certification and characterization of uranium compounds. In order to reduce the analysis and diminish the influence if the annalist, a semi-automatic version of the method was developed at the safeguards laboratory of the CNEN-RJ, Brazil. The method was applied with traceability guaranteed by use of primary standard of potassium dichromate. The standard uncertainty combined in the determination of concentration of total uranium was of the order of 0.01%, which is better related to traditionally methods used by the nuclear installations which is of the order of 0.1%

Developments in natural uranium - graphite reactors

International Nuclear Information System (INIS)

Bourgeois, J.

1964-01-01

The French natural uranium-graphite power-reactor programme has been developing - from EDF 1 to EDF 4 - in the direction of an increase of the unit power of the installations, of the specific and volume powers, and of an improvement in the operational security conditions. The high power of EDF 4 (500 MWe) and the integration of the primary circuit into the reactor vessel, which is itself made of pre-stressed concrete, make it possible to make the most of the annular fuel elements already in use in EDF 1, and to arrive thus at a very satisfactory solution. The use of an internally cooled fuel element (an annular element) has led to a further step forward: it now becomes possible to increase the pressure of the cooling gas without danger of causing creep in the uranium tube. The use of a pre-stressed concrete vessel makes this pressure increase possible, and the integration of the primary circuit avoids the risk of a rapid depressurization which would be in this case a major danger. This report deals with the main problems presented by this new type of nuclear power station, and gives the main lines of research and studies now being carried out in France. - Neutronic and thermal research has made it possible to consider using large size fuel elements (internal diameter = 77 mm, external diameter 95 mm) while still using natural uranium. - The problems connected with the production of these elements and with their in pile behaviour are the subject of a large programme, both out of pile and in power reactors (EDF 2) and test reactors (Pegase). - The increase in the size of the element leads to a large lattice pitch (35 to 40 cm). This makes it possible to consider having one charging aperture per channel or for a small number of channels, whether the charge machine be inside or outside the pressure vessel. In conclusion are given the main characteristics of a project for a 500 MWe power station using such a fuel element. In particular this project is compared to EDF 4

Influence of Uranium on Bacterial Communities: A Comparison of Natural Uranium-Rich Soils with Controls

Science.gov (United States)

Mondani, Laure; Benzerara, Karim; Carrière, Marie; Christen, Richard; Mamindy-Pajany, Yannick; Février, Laureline; Marmier, Nicolas; Achouak, Wafa; Nardoux, Pascal; Berthomieu, Catherine; Chapon, Virginie

2011-01-01

This study investigated the influence of uranium on the indigenous bacterial community structure in natural soils with high uranium content. Radioactive soil samples exhibiting 0.26% - 25.5% U in mass were analyzed and compared with nearby control soils containing trace uranium. EXAFS and XRD analyses of soils revealed the presence of U(VI) and uranium-phosphate mineral phases, identified as sabugalite and meta-autunite. A comparative analysis of bacterial community fingerprints using denaturing gradient gel electrophoresis (DGGE) revealed the presence of a complex population in both control and uranium-rich samples. However, bacterial communities inhabiting uraniferous soils exhibited specific fingerprints that were remarkably stable over time, in contrast to populations from nearby control samples. Representatives of Acidobacteria, Proteobacteria, and seven others phyla were detected in DGGE bands specific to uraniferous samples. In particular, sequences related to iron-reducing bacteria such as Geobacter and Geothrix were identified concomitantly with iron-oxidizing species such as Gallionella and Sideroxydans. All together, our results demonstrate that uranium exerts a permanent high pressure on soil bacterial communities and suggest the existence of a uranium redox cycle mediated by bacteria in the soil. PMID:21998695

Characterization of transport properties in uranium dioxide: the case of the oxygen auto-diffusion

International Nuclear Information System (INIS)

Fraczkiewicz, M.; Baldinozzi, G.

2008-01-01

Point defects in uranium dioxide which control the transport phenomena are still badly known. The aim of this work is to show how in carrying out several experimental techniques, it is possible to demonstrate both the existence and to determine the nature (charge and localization) of predominant defects responsible of the transport phenomena in a fluorite-type structure oxide. The oxygen diffusion in the uranium dioxide illustrates this. In the first part of this work, the accent is put on the electric properties of uranium dioxide and more particularly on the variation laws of the electric conductivity in terms of temperature, of oxygen potential and of the impurities amounts present in the material. These evolutions are connected to point and charged complex defects models and the pertinence of these models is discussed. Besides, it is shown how the electric conductivity measurements can allow to define oxygen potential domains in which the concentrations in electronic carriers are controlled. This characterization being made, it is shown that the determination of the oxygen intrinsic diffusion coefficient and particularly its dependence to the oxygen potential and to the amount of impurity, allows to determine the main defect responsible to the atomic diffusion as well as its nature and its charge. In the second part, the experimental techniques to determine the oxygen diffusion coefficient are presented: there are the isotopic exchange technique for introducing the tracer in the material, and two techniques to characterize the diffusion profiles (SIMS and NRA). Examples of preliminary results are given for mono and polycrystalline samples. At last, from this methodology on uranium dioxide, studies considered to quantify the thermal and physicochemical effects are presented. Experiments considered with the aim to characterize the radiation diffusion in uranium dioxide are presented too. (O.M.)

Internal friction in uranium

International Nuclear Information System (INIS)

Selle, J.E.

1975-01-01

Results are presented of studies conducted to relate internal friction measurements in U to allotropic transformations. It was found that several internal friction peaks occur in α-uranium whose magnitude changed drastically after annealing in the β phase. All of the allotropic transformations in uranium are diffusional in nature under slow heating and cooling conditions. Creep at regions of high stress concentration appears to be responsible for high temperature internal friction in α-uranium. The activation energy for grain boundary relaxation in α-uranium was found to be 65.1 +- 4 kcal/mole. Impurity atoms interfere with the basic mechanism for grain boundary relaxation resulting in a distribution in activation energies. A considerable distribution in ln tau 0 was also found which is a measure of the distribution in local order and in the Debye frequency around a grain boundary

Uranium determination in dental ceramics

International Nuclear Information System (INIS)

Jacobson, I.; Gamboa, I.; Espinosa, G.; Moreno, A.

1984-01-01

There are many reports of high uranium concentration in dental ceramics, so they require to be controlled. The SSNTD is an optional method to determine the uranium concentration. In this work the analysis of several commercial dental ceramics used regularly in Mexico by dentists is presented. The chemical and electrochemical processes are used and the optimal conditions for high sensitivity are determined. CR-39 (allyl diglycol polycarbonate) was used as detector. The preliminary results show some materials with high uranium concentrations. Next step will be the analysis of equivalent dose and the effects in the public health. (author)

Development of high uranium-density fuels for use in research reactors

Energy Technology Data Exchange (ETDEWEB)

Ugajin, Mitsuhiro; Akabori, Mitsuo; Itoh, Akinori [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

1996-02-01

The uranium silicide U{sub 3}Si{sub 2} possesses uranium density 11.3 gU/cm{sup 3} with a congruent melting point of 1665degC, and is now successfully in use as a research reactor fuel. Another uranium silicide U{sub 3}Si and U{sub 6}Me-type uranium alloys (Me=Fe,Mn,Ni) have been chosen as new fuel materials because of the higher uranium densities 14.9 and 17.0 gU/cm{sup 3}, respectively. Experiments were carried out to fabricate miniature aluminum-dispersion plate-type and aluminum-clad disk-type fuels by using the conventional picture-frame method and a hot-pressing technique, respectively. These included the above-mentioned new fuel materials as well as U{sub 3}Si{sub 2}. Totally 14 miniplates with uranium densities from 4.0 to 6.3 gU/cm{sup 3} of fuel meat were prepared together with 28 disk-type fuel containing structurally-modified U{sub 3}Si, and subjected to the neutron irradiation in JMTR (Japan Materials Testing Reactor). Some results of postirradiation examinations are presented. (author)

Highly charged atomic physics at HIRFL-CSR

International Nuclear Information System (INIS)

Ma Xinwen; Wang Youde; Hou Mingdong; Jin Gengmin

1996-01-01

HIRFL-CSR is a proposed electron cooling storage ring optimized to accelerate and store beams of highly charged heavy ions. Several possibilities for advanced atomic physics studies are discussed, such as studies of electron-ion, ion-atoms, photon-ion-electron interactions and high resolution spectroscopy

Technology for down-blending weapons grade uranium into commercial reactor-usable uranium

International Nuclear Information System (INIS)

Arbital, J.G.; Snider, J.D.

1996-01-01

The US Department of Energy (DOE) is evaluating options for rendering surplus inventories of highly enriched uranium (HEU) incapable of being used in nuclear weapons. Weapons-capable HEU was earlier produced by enriching the uranium isotope 235 U from its natural occurring 0.71 percent isotopic concentration to at least 20 percent isotopic concentration. Now, by permanently diluting the concentration of the 235 U isotope, the weapons capability of HEU can be eliminated in a manner that is reversible only through isotope re-enrichment, and therefore, highly resistant to proliferation. To the extent that can be economically and technically justified, the down-blended, low-enriched uranium product will be made suitable for use as commercial reactor fuel. Such down-blended uranium product can also be disposed of as waste if chemical or isotopic impurities preclude its use as reactor fuel. The DOE has evaluated three candidate processes for down blending surplus HEU. These candidate processes are: (1) uranium hexafluoride blending; (2) molten uranium metal blending; and (3) uranyl nitrate solution blending. This paper describes each of these candidate processes. It also compares the relative advantages and disadvantages of each process with respect to: (1) the various forms and compounds of HEU comprising the surplus inventory, (2) the use of down-blended product as commercial reactor fuel, or (3) its disposal as waste

High-frequency acoustic charge transport in GaAs nanowires

NARCIS (Netherlands)

Büyükköse, S.; Hernandez-Minguez, A.; Vratzov, B.; Somaschini, C.; Geelhaar, L.; Riechert, H.; van der Wiel, Wilfred Gerard; Santos, P.V.

2014-01-01

The oscillating piezoelectric fields accompanying surface acoustic waves are able to transport charge carriers in semiconductor heterostructures. Here, we demonstrate high-frequency (above 1 GHz) acoustic charge transport in GaAs-based nanowires deposited on a piezoelectric substrate. The short

Electrical conductivity of uranium-antimony oxide catalysts

International Nuclear Information System (INIS)

Golunski, S.E.; Nevell, T.G.; Hucknall, D.J.

1985-01-01

The relative ionic and electronic contributions to the electrical conductivity of a uranium-antimony oxide catalyst and of USbO 5 have been determined from measurements of a.c. and d.c. conductance. Under inert atmospheres (390 to 775 K) conduction in the catalyst (predominantly USb 3 O 10 together with small proportions of Sb 2 O 4 and USbO 5 ) is associated with both electronic and effectively charged atomic point defects. Only electronic conduction occurs in USbO 5 . Under oxygen (10 to 70 kPa, 493 to 682 K) both materials are n-type semiconductors at higher temperatures, but at lower temperatures semiconducting behaviour varies with the pressure of oxygen. Heating USbO 5 in oxygen induces an ionic contribution to conductivity. Ionic conduction in the catalyst is eliminated by heating in hydrogen or propene at 470 K but is restored by heating in oxygen. It is suggested that both charged oxygen vacancies and interstitial oxide ions are involved in interactions of gaseous components with uranium-antimony oxides. With alkenes, interstitial oxide ions give rise to the products of selective partial oxidation. (author)

Electrical conductivity of uranium-antimony oxide catalysts

Energy Technology Data Exchange (ETDEWEB)

Golunski, S.E.; Nevell, T.G. (Portsmouth Polytechnic (UK)); Hucknall, D.J. (Southampton Univ. (UK). Dept. of Chemistry)

1985-05-01

The relative ionic and electronic contributions to the electrical conductivity of a uranium-antimony oxide catalyst and of USbO/sub 5/ have been determined from measurements of a.c. and d.c. conductance. Under inert atmospheres (390 to 775 K) conduction in the catalyst (predominantly USb/sub 3/O/sub 10/ together with small proportions of Sb/sub 2/O/sub 4/ and USbO/sub 5/) is associated with both electronic and effectively charged atomic point defects. Only electronic conduction occurs in USbO/sub 5/. Under oxygen (10 to 70 kPa, 493 to 682 K) both materials are n-type semiconductors at higher temperatures, but at lower temperatures semiconducting behaviour varies with the pressure of oxygen. Heating USbO/sub 5/ in oxygen induces an ionic contribution to conductivity. Ionic conduction in the catalyst is eliminated by heating in hydrogen or propene at 470 K but is restored by heating in oxygen. It is suggested that both charged oxygen vacancies and interstitial oxide ions are involved in interactions of gaseous components with uranium-antimony oxides. With alkenes, interstitial oxide ions give rise to the products of selective partial oxidation.

Determination of uranium by controlled-potential coulometry with platinum electrode

International Nuclear Information System (INIS)

Eppis, M.R.; Adelfang, P.

1990-01-01

In this work it was investigated the process by which is possible to determine uranium by means of a controlled-potential coulometry with a platinum electrode, using a reversible method, in presence of Pu(III) or Fe(II), that permits to analyze uranium and plutonium jointly with the same work electrode. The method has been adapted to be used in a standard electrochemical cell, without any modification. The determination occurs in five stages: 1) Uranium and iron reduction, with an electrolysis at -250mV vs standard calomel electrode (S.C.E.). 2) Electrolysis at +200 mV vs S.C.E. to remove the hydrogen generated in the former stage. 3) Oxidation of U(IV) to U(VI) and Fe(II) to Fe(III) by an electrolysis at +650 mV vs S.C.E. 4) Reduction of Fe(III) to Fe(II) at +200 mV vs S.C.E. 5) A new oxidation of Fe(II) to Fe(III) at +650 mV vs S.C.E. By difference between the integrated charge in the steps 3) and 5), the integrated charge corresponding to the uranium oxidation is obtained. It was necessary to determine: a) the potential and the time that is necessary to apply to realize quantitative electrochemical reduction of uranium. b) the dependence of the U/Fe concentration ratios. c) the weight of U contained in the aliqout and its influence on the method. The accuracy and precision of the method was studied and results with a standard deviation of 0.03% was obtained. Moreover, the method presents the following advantages: a) it is possible to determine U and Pu on the same aliquot; b) the process is reversible; c) the use of mercury in glove-box is avoided. (Author) [es

Establishing a Cost Basis for Converting the High Flux Isotope Reactor from High Enriched to Low Enriched Uranium Fuel

International Nuclear Information System (INIS)

Primm, Trent; Guida, Tracey

2010-01-01

Under the auspices of the Global Threat Reduction Initiative Reduced Enrichment for Research and Test Reactors Program, the National Nuclear Security Administration/Department of Energy (NNSA/DOE) has, as a goal, to convert research reactors worldwide from weapons grade to non-weapons grade uranium. The High Flux Isotope Reactor (HFIR) at Oak Ridge National Lab (ORNL) is one of the candidates for conversion of fuel from high enriched uranium (HEU) to low enriched uranium (LEU). A well documented business model, including tasks, costs, and schedules was developed to plan the conversion of HFIR. Using Microsoft Project, a detailed outline of the conversion program was established and consists of LEU fuel design activities, a fresh fuel shipping cask, improvements to the HFIR reactor building, and spent fuel operations. Current-value costs total $76 million dollars, include over 100 subtasks, and will take over 10 years to complete. The model and schedule follows the path of the fuel from receipt from fuel fabricator to delivery to spent fuel storage and illustrates the duration, start, and completion dates of each subtask to be completed. Assumptions that form the basis of the cost estimate have significant impact on cost and schedule.

Charged-particle mutagenesis II. Mutagenic effects of high energy charged particles in normal human fibroblasts

Science.gov (United States)

Chen, D. J.; Tsuboi, K.; Nguyen, T.; Yang, T. C.

1994-01-01

The biological effects of high LET charged particles are a subject of great concern with regard to the prediction of radiation risk in space. In this report, mutagenic effects of high LET charged particles are quantitatively measured using primary cultures of human skin fibroblasts, and the spectrum of induced mutations are analyzed. The LET of the charged particles ranged from 25 KeV/micrometer to 975 KeV/micrometer with particle energy (on the cells) between 94-603 MeV/u. The X-chromosome linked hypoxanthine guanine phosphoribosyl transferase (hprt) locus was used as the target gene. Exposure to these high LET charged particles resulted in exponential survival curves; whereas, mutation induction was fitted by a linear model. The Relative Biological Effect (RBE) for cell-killing ranged from 3.73 to 1.25, while that for mutant induction ranged from 5.74 to 0.48. Maximum RBE values were obtained at the LET of 150 keV/micrometer. The inactivation cross-section (alpha i) and the action cross-section for mutant induction (alpha m) ranged from 2.2 to 92.0 micrometer2 and 0.09 to 5.56 x 10(-3) micrometer2, respectively. The maximum values were obtained by 56Fe with an LET of 200 keV/micrometer. The mutagenicity (alpha m/alpha i) ranged from 2.05 to 7.99 x 10(-5) with the maximum value at 150 keV/micrometer. Furthermore, molecular analysis of mutants induced by charged particles indicates that higher LET beams are more likely to cause larger deletions in the hprt locus.

Measurements of the Properties of Highly-charged high-Z ions

International Nuclear Information System (INIS)

Augustine J. Smith, Ph.D.

2007-01-01

We had proposed carrying out a systematic experimental investigation of the atomic physics of highly charged, high-Z ions, produced in the Lawrence Livermore National Laboratory LLNL electron beam ion trap (EBIT-I) in its high energy mode, superEBIT. In particular we were going to accurately measure line positions for Δn=0 transitions in few electron high-Z ions; this was meant to enable us to investigate relativistic and quantum electrodynamics QED contributions to the energy levels as well as the nuclear properties of heavy ions. We were also going to measure cross sections for various electron-ion interactions, the degree of polarization of emitted x-rays, and radiation cooling rates of various ionization stages of highly charged, high-Z ions. This would enable us to study fundamental atomic physics of high-Z ions at relativistic electron impact energies and in the intense nuclear fields of highly ionized, high-Z ions. This would extend previous measurements we have carried out to a regime where there is a paucity of good data. These measurements were expected to generate increased theoretical interest and activity in this area. The project will extend a very successful collaboration between Morehouse College (MC) and a national laboratory LLNL, Minority student training and development are major components of the proposal

Charging of Dust Grains in a Nuclear-Induced Plasma at High Pressures

International Nuclear Information System (INIS)

Pal’, A. F.; Starostin, A. N.; Filippov, A. V.

2001-01-01

The process of dust-grain charging in plasmas produced by radioactive decay products or spontaneous fission fragments in air and xenon at high pressures is studied numerically in the hydrodynamic approximation. It is shown that, at sufficiently high rates of gas ionization, the dust grains in air are charged by electrons rather than ions, so that the grain charge in air is comparable to that in electropositive gases. The results of numerical calculations based on a complete model agree well with the experimental data. The time evolution of the grain charge is investigated, and the characteristic time scales on which the grains acquire an electric charge are established. The validity of approximate theories of dust-grain charging in electropositive and electronegative gases at high pressures is examined

The behavior of uranium in the soil/plant system with special consideration of the uranium input by mineral phosphorus fertilizer

International Nuclear Information System (INIS)

Setzer, Sascha

2014-01-01

The fate of uranium in the environment and, consequently, its hazard potential for human beings is still discussed controversially in the scientific literature. Mineral phosphorous fertilizer can contain uranium as impurity, so that their application can cause an additional input of uranium into agricultural environments. It is still unclear whether and to what extent fertilizer-derived uranium can enter the human food chain by the consumption of contaminated waters or vegetable crop products. The mobility and availability of uranium in the agricultural ecosystem is mainly determined by its behavior in the pedosphere. Due to interactions with organic and inorganic components, the pedosphere is an effective storage and filter system for pollutants and thus plays an important role for the fate of uranium in the environment. In order to improve the assessment of the hazard potential, the present study investigates the behavior of uranium in the soil/plant-system with a focus on the uranium input by mineral phosphorous fertilizer. The specific objectives were (A) to investigate the general distribution of uranium in soils, (B) to determine the effect of CaCO 3 on the sorption behavior of uranium and to quantify the effects of (C - D) varying substrate properties and (E) the application of phosphorus fertilizers on the uranium uptake by ryegrass. The results of these experiments imply that the use of mineral phosphorous fertilizers does not pose an acute risk within the meaning of consumer protection. The studied soils predominantly had a high to very high sorption capability for uranium. At the same time, a small soil-to-plant-transfer of uranium was determined, where the majority of uranium accumulated in/to the plant roots. The availability of uranium in soils and its uptake by plants can thus be classified as generally low. Furthermore, some soil parameters were identified which seem to favor a higher uranium-availability. This study found that very high and very

Low-Enriched Uranium Fuel Conversion Activities for the High Flux Isotope Reactor, Annual Report for FY 2011

Energy Technology Data Exchange (ETDEWEB)

Renfro, David G [ORNL; Cook, David Howard [ORNL; Freels, James D [ORNL; Griffin, Frederick P [ORNL; Ilas, Germina [ORNL; Sease, John D [ORNL; Chandler, David [ORNL

2012-03-01

This report describes progress made during FY11 in ORNL activities to support converting the High Flux Isotope Reactor (HFIR) from high-enriched uranium (HEU) fuel to low-enriched uranium (LEU) fuel. Conversion from HEU to LEU will require a change in fuel form from uranium oxide to a uranium-molybdenum (UMo) alloy. With both radial and axial contouring of the fuel foil and an increase in reactor power to 100 MW, calculations indicate that the HFIR can be operated with LEU fuel with no degradation in performance to users from the current levels achieved with HEU fuel. Studies are continuing to demonstrate that the fuel thermal safety margins can be preserved following conversion. Studies are also continuing to update other aspects of the reactor steady state operation and accident response for the effects of fuel conversion. Technical input has been provided to Oregon State University in support of their hydraulic testing program. The HFIR conversion schedule was revised and provided to the GTRI program. In addition to HFIR conversion activities, technical support was provided directly to the Fuel Fabrication Capability program manager.

Low-Enriched Uranium Fuel Conversion Activities for the High Flux Isotope Reactor, Annual Report for FY 2011

International Nuclear Information System (INIS)

Renfro, David G.; Cook, David Howard; Freels, James D.; Griffin, Frederick P.; Ilas, Germina; Sease, John D.; Chandler, David

2012-01-01

This report describes progress made during FY11 in ORNL activities to support converting the High Flux Isotope Reactor (HFIR) from high-enriched uranium (HEU) fuel to low-enriched uranium (LEU) fuel. Conversion from HEU to LEU will require a change in fuel form from uranium oxide to a uranium-molybdenum (UMo) alloy. With both radial and axial contouring of the fuel foil and an increase in reactor power to 100 MW, calculations indicate that the HFIR can be operated with LEU fuel with no degradation in performance to users from the current levels achieved with HEU fuel. Studies are continuing to demonstrate that the fuel thermal safety margins can be preserved following conversion. Studies are also continuing to update other aspects of the reactor steady state operation and accident response for the effects of fuel conversion. Technical input has been provided to Oregon State University in support of their hydraulic testing program. The HFIR conversion schedule was revised and provided to the GTRI program. In addition to HFIR conversion activities, technical support was provided directly to the Fuel Fabrication Capability program manager.

Uranium dioxide pellets

International Nuclear Information System (INIS)

Zawidzki, T.W.

1982-01-01

A process for the preparation of a sintered, high density, large crystal grain size uranium dioxide pellet is described which involves: (i) reacting a uranyl nitrate of formula UO 2 (NO 3 ) 2 .6H 2 O with a sulphur source, at a temperature of from about 300 deg. C to provide a sulphur-containing uranium trioxide; (ii) reacting the thus-obtained modified uranium trioxide with ammonium nitrate to form an insoluble sulphur-containing ammonium uranate; (iii) neutralizing the thus-formed slurry with ammonium hydroxide to precipitate out as an insoluble ammonium uranate the remaining dissolved uranium; (iv) recovering the thus-formed precipitates in a dry state; (v) reducing the dry precipitate to UO 2 , and forming it into 'green' pellets; and (vi) sintering the pellets in a hydrogen atmosphere at an elevated temperature

Airborne uranium, its concentration and toxicity in uranium enrichment facilities

International Nuclear Information System (INIS)

Thomas, J.; Mauro, J.; Ryniker, J.; Fellman, R.

1979-02-01

The release of uranium hexafluoride and its hydrolysis products into the work environment of a plant for enriching uranium by means of gas centrifuges is discussed. The maximum permissible mass and curie concentration of airborne uranium (U) is identified as a function of the enrichment level (i.e., U-235/total U), and chemical and physical form. A discussion of the chemical and radiological toxicity of uranium as a function of enrichment and chemical form is included. The toxicity of products of UF 6 hydrolysis in the atmosphere, namely, UO 2 F 2 and HF, the particle size of toxic particulate material produced from this hydrolysis, and the toxic effects of HF and other potential fluoride compounds are also discussed. Results of an investigation of known effects of humidity and temperature on particle size of UO 2 F 2 produced by the reaction of UF 6 with water vapor in the air are reported. The relationship of the solubility of uranium compounds to their toxic effects was studied. Identification and discussion of the standards potentially applicable to airborne uranium compounds in the working environment are presented. The effectiveness of High Efficiency Particulate (HEPA) filters subjected to the corrosive environment imposed by the presence of hydrogen fluoride is discussed

Uranium metallogenic features and prospecting potentialities in the areas around Shabazi uranium deposit in Nanling metallogenic belt

International Nuclear Information System (INIS)

Yang Shanghai

2008-01-01

Based on the actuality of exploration and research on Shabazi uranium deposit in Nanling metallogenic belt, the author analyzes and summarizes uranium metallogenic features of the deposit. Under the direction of modern metallogenic theories of uranium deposit, such as deep-source mineralization and deep prospecting for uranium deposits, it is shown that there is great mineralization and prospecting potentiality in the areas around Shabazi uranium deposit and high attention importance should be paid to the areas in the future exploration according to the synthetical analysis on geologic background of the deposit, uranium mineralization features, ore-controlling factors and systematic data of geology. (authors)

Charge identification of highly ionizing particles in desensitized nuclear emulsion using high speed read-out system

International Nuclear Information System (INIS)

Toshito, T.; Kodama, K.; Yusa, K.; Ozaki, M.; Amako, K.; Kameoka, S.; Murakami, K.; Sasaki, T.; Aoki, S.; Ban, T.; Fukuda, T.; Naganawa, N.; Nakamura, T.; Natsume, M.; Niwa, K.; Takahashi, S.; Kanazawa, M.; Kanematsu, N.; Komori, M.; Sato, S.; Asai, M.; Koi, T.; Fukushima, C.; Ogawa, S.; Shibasaki, M.; Shibuya, H.

2006-01-01

We performed an experimental study of charge identification of heavy ions from helium to carbon having energy of about 290MeV/u using an emulsion chamber. Emulsion was desensitized by means of forced fading (refreshing) to expand a dynamic range of response to highly charged particles. For the track reconstruction and charge identification, the fully automated high speed emulsion read-out system, which was originally developed for identifying minimum ionizing particles, was used without any modification. Clear track by track charge identification up to Z=6 was demonstrated. The refreshing technique has proved to be a powerful technique to expand response of emulsion film to highly ionizing particles

Machining of uranium and uranium alloys

International Nuclear Information System (INIS)

Morris, T.O.

1981-01-01

Uranium and uranium alloys can be readily machined by conventional methods in the standard machine shop when proper safety and operating techniques are used. Material properties that affect machining processes and recommended machining parameters are discussed. Safety procedures and precautions necessary in machining uranium and uranium alloys are also covered. 30 figures

Uranium recovery from slags of metallic uranium

International Nuclear Information System (INIS)

Fornarolo, F.; Frajndlich, E.U.C.; Durazzo, M.

2006-01-01

The Center of the Nuclear Fuel of the Institute of Nuclear Energy Research - IPEN finished the program of attainment of fuel development for research reactors the base of Uranium Scilicet (U 3 Si 2 ) from Hexafluoride of Uranium (UF 6 ) with enrichment 20% in weight of 235 U. In the process of attainment of the league of U 3 Si 2 we have as Uranium intermediate product the metallic one whose attainment generates a slag contend Uranium. The present work shows the results gotten in the process of recovery of Uranium in slags of calcined slags of Uranium metallic. Uranium the metallic one is unstable, pyrophoricity and extremely reactive, whereas the U 3 O 8 is a steady oxide of low chemical reactivity, what it justifies the process of calcination of slags of Uranium metallic. The calcination of the Uranium slag of the metallic one in oxygen presence reduces Uranium metallic the U 3 O 8 . Experiments had been developed varying it of acid for Uranium control and excess, nitric molar concentration gram with regard to the stoichiometric leaching reaction of temperature of the leaching process. The 96,0% income proves the viability of the recovery process of slags of Uranium metallic, adopting it previous calcination of these slags in nitric way with low acid concentration and low temperature of leaching. (author)

Microbial communities in low permeability, high pH uranium mine tailings: characterization and potential effects.

Science.gov (United States)

Bondici, V F; Lawrence, J R; Khan, N H; Hill, J E; Yergeau, E; Wolfaardt, G M; Warner, J; Korber, D R

2013-06-01

To describe the diversity and metabolic potential of microbial communities in uranium mine tailings characterized by high pH, high metal concentration and low permeability. To assess microbial diversity and their potential to influence the geochemistry of uranium mine tailings using aerobic and anaerobic culture-based methods, in conjunction with next generation sequencing and clone library sequencing targeting two universal bacterial markers (the 16S rRNA and cpn60 genes). Growth assays revealed that 69% of the 59 distinct culturable isolates evaluated were multiple-metal resistant, with 15% exhibiting dual-metal hypertolerance. There was a moderately positive correlation coefficient (R = 0·43, P tailings depth was shown to influence bacterial community composition, with the difference in the microbial diversity of the upper (0-20 m) and middle (20-40 m) tailings zones being highly significant (P tailings zone being significant (P tailings environment, along with their demonstrated capacity for transforming metal elements, suggests that these organisms have the potential to influence the long-term geochemistry of the tailings. This study is the first investigation of the diversity and functional potential of micro-organisms present in low permeability, high pH uranium mine tailings. © 2013 The Society for Applied Microbiology.

Uranium, depleted uranium, biological effects; Uranium, uranium appauvri, effets biologiques

Energy Technology Data Exchange (ETDEWEB)

NONE

2001-07-01

Physicists, chemists and biologists at the CEA are developing scientific programs on the properties and uses of ionizing radiation. Since the CEA was created in 1945, a great deal of research has been carried out on the properties of natural, enriched and depleted uranium in cooperation with university laboratories and CNRS. There is a great deal of available data about uranium; thousands of analyses have been published in international reviews over more than 40 years. This presentation on uranium is a very brief summary of all these studies. (author)

Uranium. Resources, production and demand

International Nuclear Information System (INIS)

1997-01-01

The events characterising the world uranium market in the last several years illustrate the persistent uncertainly faced by uranium producers and consumers worldwide. With world nuclear capacity expanding and uranium production satisfying only about 60 per cent of demand, uranium stockpiles continue to be depleted at a high rate. The uncertainty related to the remaining levels of world uranium stockpiles and to the amount of surplus defence material that will be entering the market makes it difficult to determine when a closer balance between uranium supply and demand will be reached. Information in this report provides insights into changes expected in uranium supply and demand until well into the next century. The 'Red Book', jointly prepared by the OECD Nuclear Energy Agency and the International Atomic Energy Agency, is the foremost reference on uranium. This world report is based on official information from 59 countries and includes compilations of statistics on resources, exploration, production and demand as of 1 January 1997. It provides substantial new information from all of the major uranium producing centres in Africa, Australia, Eastern Europe, North America and the New Independent States, including the first-ever official reports on uranium production in Estonia, Mongolia, the Russian Federation and Uzbekistan. It also contains an international expert analysis of industry statistics and worldwide projections of nuclear energy growth, uranium requirements and uranium supply

Relationship of the vibrational frequency of the uranyl ion with the uranium electronegativity

International Nuclear Information System (INIS)

Rodriguez S, A.; Martinez Q, E.

1990-07-01

It has been demonstrated that the vibrational asymmetric frequency of the uranyl ion, it experiences a consistent spectrochemical displacement with the variations of electronegativity of the uranium in their complexes. The values of the electronegativity of the uranium they were dear by means of calculations that it involves measures of those lengths of the connection uranium-oxygen, obtained by vibrational spectroscopy, effective nuclear charges and the Allred and Rochow equation. The results show the evidence of a natural order that relates to the vibrational frequency with the electronegativity of the uranium atom; settling down that if the electronegativity is graph against it bond length to the oxygen or to it frequency value, a simple relationship is obtained as a form to obtain clear responses in absence of complementary information. (Author)

Uranium and the War: The effects of depleted uranium weapons in Iraq

International Nuclear Information System (INIS)

Jon williams

2007-01-01

The U.S. Army revealed in March 2003 that it dropped between 320 and 390 tons of depleted uranium during the Gulf War-the first time the material was ever used in combat-and it is estimated that more still has been dropped during the current invasion, though there have been no official counts as yet. Nuclear weapons and nuclear power plants require highly radioactive uranium, so the uranium 238 is removed from the naturally occurring uranium by a process known as enrichment. Depleted uranium is the by-product of the uranium enrichment process. Depleted uranium was a major topic of discussion during a Feb. 24 forum at Santa Cruz with speakers from the Iraq Veterans Against War (IVAW). The panel consisted of five members of the IVAW chapter in Olympia, Washington who visited Santa Cruz as part of a speaking tour of the west coast. These members of the IVAW believe that their experiences in the Gulf War were the beginnings of what will be a long-term health problem in the region. A study conducted by the Pentagon in 2002 predicted that every future battlefield will be contaminated with depleted uranium. Up-to-date health information from Iraq is difficult to come by. But a November report from Al-jazeera concluded that the cancer rate in Iraq has increased tenfold, and the number of birth defects has multiplied fivefold times since the 1991 war. The increase is believed to be caused by depleted uranium.

A natural analogy of high-level radioactive waste disposal. A case study of the groundwater from a uranium deposit

International Nuclear Information System (INIS)

Li Xinchun; Zhang Zhanshi; Ouyang Hegen

2009-01-01

Radionuclide migration is one of the key effects of high-level radioactive waste disposal. The groundwater is considered the primary means of radionuclide migration. Uranium and rare earth element(REE) in groundwater from a uranium deposit were used as a chemical analogue to study the migration of radionuclides. The results show that REE and its chemical analogue might migrate under the uranium deposit condition, but uranium and its analogue do not migrate obviously. According to the results, we might infer that after the groundwater penetrates into the HLW repository, REE and its analogue might migrate with the groundwater; but there is no obvious migration of uranium and its chemical analogue,which might increase our confidence to built a safe HLW repository. (authors)

Analysis of leachability for a sandstone uranium deposite with high acid consumption and sensitivities in Inner Mongolia

International Nuclear Information System (INIS)

Cheng Wei; Miao Aisheng; Li Jianhua; Zhou Lei; Chang Jingtao

2014-01-01

In-situ Leaching adaptability of a ground water oxidation zone type sandstone uranium deposit from Inner Mongolia is studied. The ore of the uranium deposit has high acid consumption and sensitivities in in-situ leaching. The leaching process with agent of CO_2 + O_2 and adjusting concentration of HCO_3"- can be suitable for the deposit. (authors)

Feasibility studies on electrochemical separation and recovery of uranium by using domestic low grade uranium resources

International Nuclear Information System (INIS)

Oh, Won Zin; Jung, Chong Hun; Lee, Kune Woo; Won, Hui Jun; Choi, Wang Kyu; Kim, Gye Nam; Lee, Yu Ri; Lee, Joong Moung

2005-12-01

The up-to-date electrochemical uranium separation technology has been developed for uranium sludge waste treatment funded by a long term national nuclear technology development program. The objective of the studies is to examine applicability of the uranium separation technology to making use of the low grade uranium resources in the country. State of the arts of uranium separation and recovery from the low grade national uranium resources. - The amount of the high grade uranium resources(0.1 % U 3 O 8 contents) in the world is 1,750,000MTU and that of the low grade uranium resources(0.04 % U 3 O 8 contents) in the country is 340,000MTU. - The world uranium price will be increase to more than 30$/l0b in 10 years, so that the low grade uranium in the country become worth while to recover. - The conventional uranium recovery technologies are based on both acidic - The ACF electrochemical uranium separation technology is the state of the art technology in the world and the adsorption capability of 690 mgU/g is several ten times higher than that of a conventional zeolite and the uranium stripping efficiency by desorption is more than 99%. So, this technology is expected to replace the existing solvent extraction technology. Feasibility of the ACF electrochemical uranium separation technology as an uranium recovery method. Lab scale demonstration of uranium separation and recovery technologies have been carried out by using an ACF electrochemical method

Uranium districts in South Greenland

International Nuclear Information System (INIS)

Armour-Brown, A.; Tukiainen, T.; Wallin, B.

1981-01-01

A short review is given of reconnaissance work in South Greenland. The work has demonstrated that there are areas in the Motzfeldt centre of at least 1 km 2 with continuously high radioactivity. If the uranium content of these radioactive zones are sufficiently high, then potential ore tonnages could prove to be substantial. The reconnaissance exploration has proved that uranium mineralization is widely distributed in the Narssaq-Narssarssuaq district. It is, no doubt, responsible for the high uranium values in the exploration geochemical samples. Although the size of the pitchblende occurences which have been found so far are small, the high grade of the mineralisation, the great frequency of the fracturing and the evidence for an all pervasive mineralising event over a wide area indicate that there is a good possibility of finding economic mineralisation within the Narssaq-Narssarssuaq area. The area as a whole may, perhaps, be termed a ''uranium mineral district''. As the potential targets are small, only detailed follow-up exploration will establish this. At the same time more detailed work on individual showings, and geological mapping to demonstrate the relative ages of the various petrological and mineralising events, will establish the possible origin of this uranium mineralisation. (author)

Improvement of highly charged ion output from an ECR source

International Nuclear Information System (INIS)

Shirkov, G.D.

1995-01-01

The physical limitations of the highly charged ion production in the ECR source is analyzed in this report. General methods to increase the output ion current and the attainable charged states of heavy ions are discussed. Some new ways to improve the output of highly charged ions from the ECR source for heavy ions are proposed. A new library of computer codes for the mathematical simulation of heavy ion production in the ECR ion source is used for numerical experiments to test these ways for improving the operation of the ECR source. (orig.)

Valence-associated uranium isotope fractionation of uranium enriched phosphate in a shallow aquifer, Lee County, Florida

International Nuclear Information System (INIS)

Weinberg, J.M.; Levine, B.R.; Cowart, J.B.

1993-01-01

The source of anomalously high concentrations of uranium, characterized by U-234/U-238 activity ratios significantly less than unity, in shallow groundwaters of Lee County, Florida, was investigated. Uranium in cores samples was separated into U(IV) and U(VI) oxidation state fractions, and uranium analyses were conducted by alpha spectrometry. Uranium mobility was also studied in selected leaching experiments. Results indicate that mobilization of unusually soluble uranium, present in uranium enriched phosphate of the Pliocene age Tamiami Formation at determined concentrations of up to 729 ppm, is the source for high uranium concentrations in groundwater. In leaching experiments, approximately one-third of the uranium present in the uranium enriched phosphate was mobilized into the aqueous phase. Results of previous investigations suggest that U-234, produced in rock by U-238 decay, is selectively oxidized to U(VI). The uranium enriched phosphate studied in this investigation is characterized by selective reduction of U-234, with a pattern of increasing isotopic fractionation with core depth. As a consequence, U-234/U-238 activity ratios greater than 1.0 in the U(IV) fraction, and less than 1.0 in the U(VI) fraction have developed in the rock phase. In leaching experiments, the U(VI) fraction from the rock was preferentially mobilized into the aqueous phase, suggesting that U-234/U-238 activity ratios of leaching groundwaters are strongly influenced by the isotopic characteristics of the U(VI) fraction of rock. It is suggested that preferential leaching of U(VI), present in selectivity reduced uranium enriched phosphate, is the source for low activity ratio groundwaters in Lee County

Uranium isotopes in ground water as a prospecting technique

International Nuclear Information System (INIS)

Cowart, J.B.; Osmond, J.K.

1980-02-01

The isotopic concentrations of dissolved uranium were determined for 300 ground water samples near eight known uranium accumulations to see if new approaches to prospecting could be developed. It is concluded that a plot of 234 U/ 238 U activity ratio (A.R.) versus uranium concentration (C) can be used to identify redox fronts, to locate uranium accumulations, and to determine whether such accumulations are being augmented or depleted by contemporary aquifer/ground water conditions. In aquifers exhibiting flow-through hydrologic systems, up-dip ground water samples are characterized by high uranium concentration values (> 1 to 4 ppB) and down-dip samples by low uranium concentration values (less than 1 ppB). The boundary between these two regimes can usually be identified as a redox front on the basis of regional water chemistry and known uranium accumulations. Close proximity to uranium accumulations is usually indicated either by very high uranium concentrations in the ground water or by a combination of high concentration and high activity ratio values. Ground waters down-dip from such accumulations often exhibit low uranium concentration values but retain their high A.R. values. This serves as a regional indicator of possible uranium accumulations where conditions favor the continued augmentation of the deposit by precipitation from ground water. Where the accumulation is being dispersed and depleted by the ground water system, low A.R. values are observed. Results from the Gulf Coast District of Texas and the Wyoming districts are presented

Photoproduction of charged particle with high transverse momentum

International Nuclear Information System (INIS)

Campos Costa Ramos, S.E. de.

1986-09-01

Inclusive cross sections of high transverse moment charged pions induced by a high energy photon beam have been measured. These results do not account, neither in slope nor in normalisation, for the VDM component of the photon, evaluated with pion induced data taken in the same experimental conditions after VDM subtraction, excellent agreement is found with QCD calculations up to second order in α s , in an extended cinematic region, different choices of the gluon fragmentation function do not alter this conclusion. Our measures of the inclusive final state charge asymmetries also confirm QCD expectations. 42 refs [fr

Charged-particle mutagenesis 2. Mutagenic effects of high energy charged particles in normal human fibroblasts

Science.gov (United States)

Chen, D. J.; Tsuboi, K.; Nguyen, T.; Yang, T. C.

1994-01-01

The biological effects of high Linear Energy Transfer (LET) charged particles are a subject of great concern with regard to the prediction of radiation risk in space. In this report, mutagenic effects of high LET charged particles are quantitatively measured using primary cultures of human skin fibroblasts, and the spectrum of induced mutations are analyzed. The LET of the charged particles ranged from 25 KeV/micrometer to 975 KeV/micrometer with particle energy (on the cells) between 94-603 MeV/u. The X-chromosome linked hypoxanthine guanine phosphoribosyl transferase (hprt) locus was used as the target gene. Exposure to these high LET charged particles resulted in exponential survival curves; whereas, mutation induction was fitted by a linear model. The Relative Biological Effect (RBE) for cell-killing ranged from 3.73 to 1.25, while that for mutant induction ranged from 5.74 to 0.48. Maximum RBE values were obtained at the LET of 150 keV/micrometer. The inactivation cross-section (alpha i) and the action cross-section for mutant induction (alpha m) ranged from 2.2 to 92.0 sq micrometer and 0.09 to 5.56 x 10(exp -3) sq micrometer respectively. The maximum values were obtained by Fe-56 with an LET of 200 keV/micrometer. The mutagenicity (alpha m/alpha i) ranged from 2.05 to 7.99 x 10(exp -5) with the maximum value at 150 keV/micrometer. Furthermore, molecular analysis of mutants induced by charged particles indicates that higher LET beams are more likely to cause larger deletions in the hprt locus.

Charge-density waves in alpha-uranium: A story of endless surprises

International Nuclear Information System (INIS)

Lander, G.H.

1982-01-01

The properties of element 92, uranium at low temperature have remained an enigma since major anomalies in almost all physical property measurements were first reported over twenty years ago. By far the most dramatic measurements were those by Fisher on the elastic constants, which strongly suggested a structural phase transition at approx. equal to43 K. Initially no such phase transition was found. Recently, neutron inelastic experiments at Oak Ridge mapped out the phonon dispersion curves at room temperature, and in the process discovered an anomalous soft phonon of Σ 4 symmetry along the [100] axis. On cooling, weak satellites were found to form near the position [0.5, 0.0] thus signaling a periodic distortion. However, such a charge-density wave appeared to have a complex wave vector relationship with the fundamental lattice, leading the authors to introduce a two-phase model for the phase transition. Simultaneously, by using photographic technique designed to view large segments of reciprocal space, Marmeggi and Delapalme at the ILL discovered a completely new set of satellite reflections, indexable with wave vector [0.5, qsub(y), qsub(z)], where qsub(y) and qsub(z) are incommensurable (approx. equal to0.18), not equal, and vary with temperature. We have now measured the intensities of a great number of these new satellites and been able to fit the results with a modulated α-U structure. The atoms are displaced in all three independent crystallographic directions according to a sinusoidal wave form. The overall agreement between the predicted and observed structure factors is excellent, suggesting that at least the static positions of the atoms at low temperature in this element are now understood. In this review the status of research on the structural phase transition will be presented. Neither the full details of the phase transition nor the reasons for it are understood at this time. A number of further experiments are suggested. (orig.)

Fungi outcompete bacteria under increased uranium concentration in culture media

International Nuclear Information System (INIS)

Mumtaz, Saqib; Streten-Joyce, Claire; Parry, David L.; McGuinness, Keith A.; Lu, Ping; Gibb, Karen S.

2013-01-01

As a key part of water management at the Ranger Uranium Mine (Northern Territory, Australia), stockpile (ore and waste) runoff water was applied to natural woodland on the mine lease in accordance with regulatory requirements. Consequently, the soil in these Land Application Areas (LAAs) presents a range of uranium concentrations. Soil samples were collected from LAAs with different concentrations of uranium and extracts were plated onto LB media containing no (0 ppm), low (3 ppm), medium (250 ppm), high (600 ppm) and very high (1500 ppm) uranium concentrations. These concentrations were similar to the range of measured uranium concentrations in the LAAs soils. Bacteria grew on all plates except for the very high uranium concentrations, where only fungi were recovered. Identifications based on bacterial 16S rRNA sequence analysis showed that the dominant cultivable bacteria belonged to the genus Bacillus. Members of the genera Paenibacillus, Lysinibacillus, Klebsiella, Microbacterium and Chryseobacterium were also isolated from the LAAs soil samples. Fungi were identified by sequence analysis of the intergenic spacer region, and members of the genera Aspergillus, Cryptococcus, Penicillium and Curvularia were dominant on plates with very high uranium concentrations. Members of the Paecilomyces and Alternaria were also present but in lower numbers. These findings indicate that fungi can tolerate very high concentrations of uranium and are more resistant than bacteria. Bacteria and fungi isolated at the Ranger LAAs from soils with high concentrations of uranium may have uranium binding capability and hence the potential for uranium bioremediation. -- Highlights: ► Fungi outcompete bacteria under increased uranium concentration in culture media. ► Soil microorganisms isolated from the Ranger Land Application Areas (LAAs) were resistant to uranium. ► Bacillus was the most abundant cultivable genus retrieved from the Ranger LAAs soils. ► Uranium in LAAs soils is

Uranium occurrences of the Thunder Bay-Nipigon-Marathon area

International Nuclear Information System (INIS)

Scott, J.F.

1987-01-01

During the 1981, 1982 and 1983 field seasons an inventory of all known uranium occurrences in the North Central Region of Ontario was undertaken. Three major categories of uranium occurrences were identified: uranium associated with the rocks of the Quetico Subprovince; uranium associated with the Proterozoic/Archean unconformity; and uranium associated with alkalic and carbonatite rocks of Late Precambrian age. Occurrences associated with the Quetico Belt are in white, albite-quartz-muscovite pegmatites. Occurrences associated with the Proterozoic/Archean unconformity are usually of high gradee (up to 12% U 3 O 8 ), nearly always hematized and are related to fault or shear zones proximal to the unconformity. Although of high grade, many of the unconformity related occurrences are very narrow (<1 m). Alkalic and carbonatite rocks of Late Precambrian age are an important source of uranium but possible metallurgical problems might downgrade their potential. The Quetico Subprovince is anomalously high in background uranium, and therefore contains important source rocks for uranium. Areas that have the highest potential for uranium deposits in the North Central Region are the Nipigon Basin area, and the areas underlain by the Gunflint and Rove Formations. All the high grade vein-type uranium deposits related to the unconformity are found within the Nipigon Basin. 126 refs

Interaction of slow highly-charged ions with metals and insulators

International Nuclear Information System (INIS)

Yamazaki, Y.

2007-01-01

Interaction of slow highly charged ions with insulator as well as metallic surfaces is discussed. In addition to the usual flat surface targets, studies with thin foils having a multitude of straight holes of ∼100 nm in diameter (micro-capillary foil) are introduced, which provide various unique information on the above surface interaction. In the case of an insulator micro-capillary foil, a so-called guiding effect was observed, where slow highly charged ions can transmit through the capillary tunnel keeping their initial charge state even when the capillary axis is tilted against the incident beam. A similar guiding effect has recently been found for slow highly-charged ions transmitted through a single tapered glass capillary. In both cases, the guiding effects are expected to be governed by a self-organized charging and discharging of the inner-wall of the insulator capillary. One of the prominent features of this guiding effect with the tapered capillary is the formation of a nano-size beam, which can be applied in various fields of science including surface nano-modification/analysis, nano-surgery of living cells, etc

Electrolytic recovery of uranium oxides

International Nuclear Information System (INIS)

Gurr, W.R.

1979-01-01

A method is described for extracting uranium oxide from a solution of one or more uranium compounds, e.g. leach liquors, comprising subjecting the solution to electrolysis utilizing a high current density, e.g. 500 to 4000 amp/m 2 , whereby uranium oxide is formed at the cathode and is recovered. The method is particularly suited to a continuous process using a rotating cathode cell. (author)

DYNAMIC PROPERTIES OF SHOCK LOADED THIN URANIUM FOILS

International Nuclear Information System (INIS)

Robbins, D.L.; Kelly, A.M.; Alexander, D.J.; Hanrahan, R.J.; Snow, R.C.; Gehr, R.J.; Rupp, Ted Dean; Sheffield, S.A.; Stahl, D.B.

2001-01-01

A series of spall experiments has been completed with thin depleted uranium targets, nominally 0.1 mm thick. The first set of uranium spall targets was cut and ground to final thickness from electro-refined, high-purity, cast uranium. The second set was rolled to final thickness from low purity uranium. The impactors for these experiments were laser-launched 0.05-mm thick copper flyers, 3 mm in diameter. Laser energies were varied to yield a range of flyer impact velocities. This resulted in varying degrees of damage to the uranium spall targets, from deformation to complete spall or separation at the higher velocities. Dynamic measurements of the uranium target free surface velocities were obtained with dual velocity interferometers. Uranium targets were recovered and sectioned after testing. Free surface velocity profiles were similar for the two types of uranium, but spall strengths (estimated from the magnitude of the pull-back signal) are higher for the high-purity cast uranium. Velocity profiles and microstructural evidence of spall from the sectioned uranium targets are presented.

Reactive transport modeling of uranium 238 and radium 226 in groundwater of the Königstein uranium mine, Germany

Science.gov (United States)

Nitzsche, O.; Merkel, B.

Knowledge of the transport behavior of radionuclides in groundwater is needed for both groundwater protection and remediation of abandoned uranium mines and milling sites. Dispersion, diffusion, mixing, recharge to the aquifer, and chemical interactions, as well as radioactive decay, should be taken into account to obtain reliable predictions on transport of primordial nuclides in groundwater. This paper demonstrates the need for carrying out rehabilitation strategies before closure of the Königstein in-situ leaching uranium mine near Dresden, Germany. Column experiments on drilling cores with uranium-enriched tap water provided data about the exchange behavior of uranium. Uranium breakthrough was observed after more than 20 pore volumes. This strong retardation is due to the exchange of positively charged uranium ions. The code TReAC is a 1-D, 2-D, and 3-D reactive transport code that was modified to take into account the radioactive decay of uranium and the most important daughter nuclides, and to include double-porosity flow. TReAC satisfactorily simulated the breakthrough curves of the column experiments and provided a first approximation of exchange parameters. Groundwater flow in the region of the Königstein mine was simulated using the FLOWPATH code. Reactive transport behavior was simulated with TReAC in one dimension along a 6000-m path line. Results show that uranium migration is relatively slow, but that due to decay of uranium, the concentration of radium along the flow path increases. Results are highly sensitive to the influence of double-porosity flow. Résumé La protection des eaux souterraines et la restauration des sites miniers et de prétraitement d'uranium abandonnés nécessitent de connaître le comportement des radionucléides au cours de leur transport dans les eaux souterraines. La dispersion, la diffusion, le mélange, la recharge de l'aquifère et les interactions chimiques, de même que la décroissance radioactive, doivent être

Spectroscopy with trapped highly charged ions

International Nuclear Information System (INIS)

Beiersdorfer, Peter

2009-01-01

We give an overview of atomic spectroscopy performed on electron beam ion traps at various locations throughout the world. Spectroscopy at these facilities contributes to various areas of science and engineering, including but not limited to basic atomic physics, astrophysics, extreme ultraviolet lithography, and the development of density and temperature diagnostics of fusion plasmas. These contributions are accomplished by generating, for example, spectral surveys, making precise radiative lifetime measurements, accounting for radiative power emitted in a given wavelength band, illucidating isotopic effects, and testing collisional-radiative models. While spectroscopy with electron beam ion traps had originally focused on the x-ray emission from highly charged ions interacting with the electron beam, the operating modes of such devices have expanded to study radiation in almost all wavelength bands from the visible to the hard x-ray region; and at several facilities the ions can be studied even in the absence of an electron beam. Photon emission after charge exchange or laser excitation has been observed; and the work is no longer restricted to highly charged ions. Much of the experimental capabilities are unique to electron beam ion traps, and the work performed with these devices cannot be undertaken elsewhere. However, in other areas the work on electron beam ion traps rivals the spectroscopy performed with conventional ion traps or heavy-ion storage rings. The examples we present highlight many of the capabilities of the existing electron beam ion traps and their contributions to physics.

Process for continuous production of metallic uranium and uranium alloys

Science.gov (United States)

Hayden, Jr., Howard W.; Horton, James A.; Elliott, Guy R. B.

1995-01-01

A method is described for forming metallic uranium, or a uranium alloy, from uranium oxide in a manner which substantially eliminates the formation of uranium-containing wastes. A source of uranium dioxide is first provided, for example, by reducing uranium trioxide (UO.sub.3), or any other substantially stable uranium oxide, to form the uranium dioxide (UO.sub.2). This uranium dioxide is then chlorinated to form uranium tetrachloride (UCl.sub.4), and the uranium tetrachloride is then reduced to metallic uranium by reacting the uranium chloride with a metal which will form the chloride of the metal. This last step may be carried out in the presence of another metal capable of forming one or more alloys with metallic uranium to thereby lower the melting point of the reduced uranium product. The metal chloride formed during the uranium tetrachloride reduction step may then be reduced in an electrolysis cell to recover and recycle the metal back to the uranium tetrachloride reduction operation and the chlorine gas back to the uranium dioxide chlorination operation.

Process for continuous production of metallic uranium and uranium alloys

Science.gov (United States)

Hayden, H.W. Jr.; Horton, J.A.; Elliott, G.R.B.

1995-06-06

A method is described for forming metallic uranium, or a uranium alloy, from uranium oxide in a manner which substantially eliminates the formation of uranium-containing wastes. A source of uranium dioxide is first provided, for example, by reducing uranium trioxide (UO{sub 3}), or any other substantially stable uranium oxide, to form the uranium dioxide (UO{sub 2}). This uranium dioxide is then chlorinated to form uranium tetrachloride (UCl{sub 4}), and the uranium tetrachloride is then reduced to metallic uranium by reacting the uranium chloride with a metal which will form the chloride of the metal. This last step may be carried out in the presence of another metal capable of forming one or more alloys with metallic uranium to thereby lower the melting point of the reduced uranium product. The metal chloride formed during the uranium tetrachloride reduction step may then be reduced in an electrolysis cell to recover and recycle the metal back to the uranium tetrachloride reduction operation and the chlorine gas back to the uranium dioxide chlorination operation. 4 figs.

Uranium exploration, mining and ore enrichment techniques

International Nuclear Information System (INIS)

Fuchs, H.D.; Wentzlau, D.

1985-01-01

The paper describes the different types of uranium deposits and their importance. It is shown that during the present depressed uranium market situation, mainly high grade deposits such as unconformity-related deposits can be mined economically. The different successive exploration steps are outlined including methods used for uranium. Uranium mining does not greatly differ from normal mining, but the uranium metallurgy needs its own specialized but already classic technology. Only a relative small amount of uranium can be expected from projects where uranium is produced by in situ leach methods or by extraction from phosphoric acid. A short summary of investment costs and operating costs is given for an average uranium mine. The last chapter deals with the definition of different reserve categories and outlines the uranium reserves of the western world including the uranium production (1983) and the expected uranium production capacity for 1985 and 1990. (orig.) [de

High charge state heavy ion production from a PIG source

International Nuclear Information System (INIS)

Bex, L.; Clark, D.J.; Ellsworth, C.E.; Flood, W.S.; Gough, R.A.; Holley, W.R.; Meriwether, J.R.; Morris, D.

1975-03-01

The comparison of pulsed vs. dc arc operation for nitrogen and argon shows a shift in charge distribution toward the higher charge states for the pulsed case. Tests with various magnetic field shapes along the arc column show a significant increase in high charge state output for a uniform field compared to the case with a field low at the cathodes. (U.S.)

Thermoluminescence applied to uranium exploration and genesis of the Westmoreland uranium deposits - implications for the Northern Territory

International Nuclear Information System (INIS)

Hochman, M.B.M.; Ypma, P.J.M.

1984-01-01

The Westmoreland uranium deposits occur on the northern flank of the Murphy Tectonic Ridge in the upper member of the Westmoreland Conglomerate. Uranium mineralisation is spatially associated with the contact of the overlying basaltic Siegal Volcanics and the margins of intrusive dolerite dykes which are geochemically similar to the Siegal Volcanics. Thermoluminescence measurements on 800 samples from within the orebodies and surrounding host rock have indicated that all of the Westmoreland Conglomerate has suffered major radiation damage attributable to at least 10 ppm uranium over 10 9 years. The underlying rhyolitic Mid Proterozoic Cliffdale Volcanics have distinctive TL glow curves indicative of radiation sensitisation caused by high uranium contents. These volcanics are part of the Mid Proterozoic volcanic event known to be enriched in uranium. The Westmoreland Conglomerate has been derived by erosion of the uranium-rich Cliffdale Volcanics and associated Nicholson Granite Complex which makes it likely that the Westmoreland Conglomerate had a high inherent uranium content. It is proposed that this precontained uranium within the Westmoreland Conglomerate was remobilized in a convective cell system possibly triggered by intrusion of dolerite dykes, or by a later rejuvenation of vertical structures which provided an ascending heat flow. Pitchblende was precipitated where suitable reducing conditions existed close to the basic volcanics and dykes

Repository emplacement costs for Al-clad high enriched uranium spent fuel

International Nuclear Information System (INIS)

McDonell, W.R.; Parks, P.B.

1994-01-01

A range of strategies for treatment and packaging of Al-clad high-enriched uranium (HEU) spent fuels to prevent or delay the onset of criticality in a geologic repository was evaluated in terms of the number of canisters produced and associated repository costs incurred. The results indicated that strategies in which neutron poisons were added to consolidated forms of the U-Al alloy fuel generally produced the lowest number of canisters and associated repository costs. Chemical processing whereby the HEU was removed from the waste form was also a low cost option. The repository costs generally increased for isotopic dilution strategies, because of the substantial depleted uranium added. Chemical dissolution strategies without HEU removal were also penalized because of the inert constituents in the final waste glass form. Avoiding repository criticality by limiting the fissile mass content of each canister incurred the highest repository costs

Study on Kalimantan uranium province: The assessment on uranium mineralization of metamorphic and granitic rocks at Schwaner mountains

International Nuclear Information System (INIS)

Tjokrokardono, Soeprapto

2002-01-01

Uranium exploration activities done by CEA-BATAN had discovered uranium occurrences as the radiometric and uranium content anomalies at metamorphic and granite rocks of Schwaner Mountains, Kalimantan. A part of the occurrences on metamorphic rocks at Kalan basin has been evaluated and be developed onto follow-up step of prospecting by construction of some drilling holes and an exploration adit. In order to increase the national uranium resources, it is necessarily to extent the exploration activity to out side or nearby of Kalan basin. The goal of this assessment is to understand the uranium accumulation mechanism at Pinoh metamorphic rocks of Kalan Kalimantan and to delineate areas that uranium may exist. The assessment was based on the aspect of geology, anomaly of radioactivity and uranium contents, tectonics and alterations. Pinoh metamorphic rocks which is influenced by Sukadana granite intrusion are the high potential rocks for the uranium accumulation, because the intrusion contains a relatively high of U, Th, Cu, Zn, Nb, Mn, and W. The potential rock distributions are in between G. Ransa granite intrusion at the east and Kotabaru granite intrusions at the west. The mineralizations are categorized as vein type deposits of granitic association

The discovery and character of Pleistocene calcrete uranium deposits in the Southern High Plains of west Texas, United States

Science.gov (United States)

Van Gosen, Bradley S.; Hall, Susan M.

2017-12-18

This report describes the discovery and geology of two near-surface uranium deposits within calcareous lacustrine strata of Pleistocene age in west Texas, United States. Calcrete uranium deposits have not been previously reported in the United States. The west Texas uranium deposits share characteristics with some calcrete uranium deposits in Western Australia—uranium-vanadium minerals hosted by nonpedogenic calcretes deposited in saline lacustrine environments.In the mid-1970s, Kerr-McGee Corporation conducted a regional uranium exploration program in the Southern High Plains province of the United States, which led to the discovery of two shallow uranium deposits (that were not publicly reported). With extensive drilling, Kerr-McGee delineated one deposit of about 2.1 million metric tons of ore with an average grade of 0.037 percent U3O8 and another deposit of about 0.93 million metric tons of ore averaging 0.047 percent U3O8.The west-Texas calcrete uranium-vanadium deposits occur in calcareous, fine-grained sediments interpreted to be deposited in saline lakes formed during dry interglacial periods of the Pleistocene. The lakes were associated with drainages upstream of a large Pleistocene lake. Age determinations of tephra in strata adjacent to one deposit indicate the host strata is middle Pleistocene in age.Examination of the uranium-vanadium mineralization by scanning-electron microscopy indicated at least two generations of uranium-vanadium deposition in the lacustrine strata identified as carnotite and a strontium-uranium-vanadium mineral. Preliminary uranium-series results indicate a two-component system in the host calcrete, with early lacustrine carbonate that was deposited (or recrystallized) about 190 kilo-annum, followed much later by carnotite-rich crusts and strontium-uranium-vanadium mineralization in the Holocene (about 5 kilo-annum). Differences in initial 234U/238U activity ratios indicate two separate, distinct fluid sources.

Flotation of uranium from uranium ores in Canada. Part 1

International Nuclear Information System (INIS)

Muthuswami, S.V.; Vigayan, S.; Woods, D.R.; Banerjee, S.

1983-01-01

About 150 flotation tests were done on Elliot Lake ore with 15 reagents as collectors in order to screen and choose an attractive collector for uranium flotation. Several variables were studied including pH, conditioning time and mode of collector addition. The tests were done in a Denver or Agitair subaeration cell. The particle size of the ore was kept at 85% below -325 mesh. Three reagents (Kelex 00, TOPO, and cupferron) were identified as having the most promise. The best results were obtained with cupferron, where 93-95% of the uranium was recovered in 25-30% of the mass of original ore. Radium in the tails varied between 5 and 30 pCi/g depending on the mass of uranium floated. Radium was recovered in proportion to uranium in the tests done at neutral pH. The preconcentration results obtained by flotation alone were comparable to those obtained using pyrite flotation and wet high-intensity magnetic separation of uranium. The consumption of cupferron was 4 kg/Mg ore for each flotation stage. This was 10-15 times larger than the collector usage in conventional oxide flotation. This scheme did not require other reagents as depressants, activators or modifiers. Reproducibility was good and similar recoveries were obtained with fresh or old ores, and with distilled or mine water. The selectivity of cupferron for uranium in the ore studied was outstanding

Electron impact ionization of highly charged lithiumlike ions

International Nuclear Information System (INIS)

Wong, K.L.

1992-10-01

Electron impact ionization cross sections can provide valuable information about the charge-state and power balance of highly charged ions in laboratory and astrophysical plasmas. In the present work, a novel technique based on x-ray measurements has been used to infer the ionization cross section of highly charged lithiumlike ions on the Livermore electron beam ion trap. In particular, a correspondence is established between an observed x ray and an ionization event. The measurements are made at one energy corresponding to approximately 2.3 times the threshold energy for ionization of lithiumlike ions. The technique is applied to the transition metals between Z=22 (titanium, Ti 19+ ) and Z=26 (iron, Fe 23+ ) and to Z=56 (barium, Ba 53+ ). The results for the transition metals, which have an estimated 17-33% uncertainty, are in good overall agreement with a relativistic distorted-wave calculation. However, less good agreement is found for barium, which has a larger uncertainty. Methods for properly accounting for the polarization in the x-ray intensities and for inferring the charge-state abundances from x-ray observations, which were developed for the ionization measurements, as well as an x-ray model that assists in the proper interpretation of the data are also presented

Refining of high-temperature uranium melt by filtration through foam-ceramic filters

International Nuclear Information System (INIS)

Antsiferov, V.N.; Porozova, S.E.; Filippov, V.B.; Shtutsa, M.G.; Il'enko, E.V.; Kolotygina, N.S.

2004-01-01

An opportunity of applying foam-ceramic filters of corundum-mullite composition has been studied in refining natural uranium melts. Uranium melting conditions were chosen depending on technical characteristics of the foam ceramic filters. When their using, a portion of nonmetallic inclusions decreases by 20-30% (as little as 2.0-3.5% ingot weight), their size is reduced and their distribution in the ingot volume is equalized, contamination of uranium by the filter material being failed to be noticed. The parameters of foam-ceramic filters are optimized for provision of stable characteristics of uranium melt filtration process [ru

Diurnal urinary volume and uranium output in uranium workers and unexposed controls

International Nuclear Information System (INIS)

Medley, D.W.; Kathren, R.L.; Miller, A.G.

1994-01-01

Volume and uranium content were determined in individual urine voids over a 76-h (3.25-d) period from six unexposed normal male subjects and three male uranium workers. Uranium analyses were accomplished by a newly developed high-precision kinetic phosphorescence analysis technique with a lower level of detection of 0.007 ng mL -1 . Urinary uranium concentrations in individual voids varied by a factor of 2 or less for any one unexposed subject, although there was an order of magnitude variation among the group of unexposed men. The fractional urinary volume excreted in the open-quotes standardclose quotes so-called simulated 24-h sample was the same for both the unexposed and exposed groups and averaged 0.42 ± 0.13 of the total daily urine volume. The fraction of uranium in the simulated 24-h samples was 0.43 ± 0.15 in the unexposed group but only 0.31 ± 0.13 in the uranium worker group, suggesting that the use of the simulated 24-h urine sample would underestimate the total daily urinary uranium output by approximately a factor of 2 in the uranium workers. Daily urinary excretion relative to intake from drinking water (essentially equal to the gastrointestinal uptake fraction) among the unexposed group ranged from 0.002-0.028, averaging 0.011 ± 0.008, with an indication that the gastrointestinal uptake factor was inversely proportional to total intake via drinking water. 11 refs., 1 fig., 6 tabs

Highly charged ions: a miniature laboratory for new fundamental science

International Nuclear Information System (INIS)

Gillaspy, J.D.

2002-01-01

Full text: Highly charged ions are 10-100 times smaller than ordinary atoms, yet they present within themselves a remarkably rich arena for testing fundamental aspects of physics. These tests are based on a precise analysis of the energy distribution of the photons that are emitted as electrons hop between energy levels within the highly charged ions. With sufficiently precise analysis, it may be possible to obtain new information about the structure of the vacuum, the effect of special relativity on many-body correlation, physics beyond the Standard Model, and the fundamental nature of quantum measurements. This talk will review the current state-of-the-art in the spectroscopy of highly charged ions, and give a look towards the future

Energetics of intrinsic point defects in uranium dioxide from electronic-structure calculations

International Nuclear Information System (INIS)

Nerikar, Pankaj; Watanabe, Taku; Tulenko, James S.; Phillpot, Simon R.; Sinnott, Susan B.

2009-01-01

The stability range of intrinsic point defects in uranium dioxide is determined as a function of temperature, oxygen partial pressure, and non-stoichiometry. The computational approach integrates high accuracy ab initio electronic-structure calculations and thermodynamic analysis supported by experimental data. In particular, the density functional theory calculations are performed at the level of the spin polarized, generalized gradient approximation and includes the Hubbard U term; as a result they predict the correct anti-ferromagnetic insulating ground state of uranium oxide. The thermodynamic calculations enable the effects of system temperature and partial pressure of oxygen on defect formation energy to be determined. The predicted equilibrium properties and defect formation energies for neutral defect complexes match trends in the experimental literature quite well. In contrast, the predicted values for charged complexes are lower than the measured values. The calculations predict that the formation of oxygen interstitials becomes increasingly difficult as higher temperatures and reducing conditions are approached

Temperature Dependence of Charge Localization in High-Mobility, Solution-Crystallized Small Molecule Semiconductors Studied by Charge Modulation Spectroscopy

DEFF Research Database (Denmark)

Meneau, Aurélie Y. B.; Olivier, Yoann; Backlund, Tomas

2016-01-01

In solution-processable small molecule semiconductors, the extent of charge carrier wavefunction localization induced by dynamic disorder can be probed spectroscopically as a function of temperature using charge modulation spectroscopy (CMS). Here, it is shown based on combined fi eld-effect tran......In solution-processable small molecule semiconductors, the extent of charge carrier wavefunction localization induced by dynamic disorder can be probed spectroscopically as a function of temperature using charge modulation spectroscopy (CMS). Here, it is shown based on combined fi eld......-effect transistor and CMS measurements as a function of temperature that in certain molecular semiconductors, such as solution-processible pentacene, charge carriers become trapped at low temperatures in environments in which the charges become highly localized on individual molecules, while in some other molecules...

Highly Efficient Interception and Precipitation of Uranium(VI) from Aqueous Solution by Iron-Electrocoagulation Combined with Cooperative Chelation by Organic Ligands.

Science.gov (United States)

Li, Peng; Zhun, Bao; Wang, Xuegang; Liao, PingPing; Wang, Guanghui; Wang, Lizhang; Guo, Yadan; Zhang, Weimin

2017-12-19

A new strategy combining iron-electrocoagulation and organic ligands (OGLs) cooperative chelation was proposed to screen and precipitate low concentrations (0-18.52 μmol/L) of uranium contaminant in aqueous solution. We hypothesized that OGLs with amino, hydroxyl, and carboxyl groups hydrophobically/hydrophilically would realize precuring of uranyl ion at pH electrocoagulation would achieve faster and more efficient uranium precipitation. Experimentally, the strategy demonstrated highly efficient uranium(VI) precipitation efficiency, especially with hydrophilic macromolecular OGLs. The uranium removal efficiency at optimized experimental condition reached 99.65%. The decrease of zeta potential and the lattice enwrapping between U-OGLs chelates and flocculation precursor were ascribed to the enhanced uranium precipitation activity. Uranium was precipitated as oxides of U(VI) or higher valences that were easily captured in aggregated micelles under low operation current potential. The actual uranium tailing wastewater was treated, and a satisfied uranium removal efficiency of 99.02% was discovered. After elution of the precipitated flocs, a concentrated uranium solution (up to 106.52 μmol/L) with very few other metallic impurities was obtained. Therefore, the proposed strategy could remove uranium and concentrate it concurrently. This work could provide new insights into the purification and recovery of uranium from aqueous solutions in a cost-effective and environmentally friendly process.

World uranium resources

International Nuclear Information System (INIS)

Deffeyes, K.S.; MacGregor, I.D.

1980-01-01

To estimate the total resource availability of uranium, the authors' approach has been to ask whether the distribution of uranium in the earth's crust can be reasonably approximated by a bell-shaped log-normal curve. In addition they have asked whether the uranium deposits actually mined appear to be a portion of the high-grade tail, or ascending slope, of the distribution. This approach preserves what they feel are the two most important guiding principles of Hubbert's work, for petroleum, namely recognizing the geological framework that contains the deposits of interest and examining the industry's historical record of discovering those deposits. Their findings, published recently in the form of a book-length report prepared for the US Department of Energy, suggest that for uranium the crustal-distribution model and the mining-history model can be brought together in a consistent picture. In brief, they conclude that both sets of data can be described by a single log-normal curve, the smoothly ascending slope of which indicates approximately a 300-fold increase in the amount of uranium recoverable for each tenfold decrease in ore grade. This conclusion has important implications for the future availability of uranium. They hasten to add, however, that this is only an approximative argument; no rigorous statistical basis exists for expecting a log-normal distribution. They continue, pointing out the enormously complex range of geochemical behavior of uranium - and its wide variety of different binds of economic deposit. Their case study, supported by US mining records, indicates that the supply of uranium will not be a limiting factor in the development of nuclear power

High temperature electron beam ion source for the production of single charge ions of most elements of the Periodic Table

CERN Document Server

Panteleev, V N; Barzakh, A E; Fedorov, D V; Ivanov, V S; Moroz, F V; Orlov, S Y; Seliverstov, D M; Stroe, L; Tecchio, L B; Volkov, Y M

2003-01-01

A new type of a high temperature electron beam ion source (HTEBIS) with a working temperature up to 2500 deg. C was developed for production of single charge ions of practically all elements. Off-line tests and on-line experiments making use of the developed ion source coupled with uranium carbide targets of different density, have been carried out. The ionization efficiency measured for stable atoms of many elements varied in the interval of 1-6%. Using the HTEBIS, the yields and on-line production efficiency of neutron rich isotopes of Mn, Fe, Co, Cu, Rh, Pd, Ag, Cd, In, Sn and isotopes of heavy elements Pb, Bi, Po and some others have been determined. The revealed confinement effect of the ions produced in the narrow electron beam inside a hot ion source cavity has been discussed.

High density thermite mixture for shaped charge ordnance disposal

Directory of Open Access Journals (Sweden)

Tamer Elshenawy

2017-10-01

Full Text Available The effect of thermite mixture based on aluminum and ferric oxides for ammunition neutralization has been studied and tested. Thermochemical calculations have been carried out for different percentage of Al using Chemical Equilibrium Code to expect the highest performance thermite mixture used for shaped charge ordnance disposal. Densities and enthalpy of different formulations have been calculated and demonstrated. The optimized thermite formulation has been prepared experimentally using cold iso-static pressing technique, which exhibited relatively high density and high burning rate thermite mixture. The produced green product compacted powder mixture was tested against small caliber shaped charge bomblet for neutralization. Theoretical and experimental results showed that the prepared thermite mixture containing 33% of aluminum as a fuel with ferric oxide can be successfully used for shaped charge ordnance disposal.

Uranium tailings sampling manual

International Nuclear Information System (INIS)

Feenstra, S.; Reades, D.W.; Cherry, J.A.; Chambers, D.B.; Case, G.G.; Ibbotson, B.G.

1985-01-01

The purpose of this manual is to describe the requisite sampling procedures for the application of uniform high-quality standards to detailed geotechnical, hydrogeological, geochemical and air quality measurements at Canadian uranium tailings disposal sites. The selection and implementation of applicable sampling procedures for such measurements at uranium tailings disposal sites are complicated by two primary factors. Firstly, the physical and chemical nature of uranium mine tailings and effluent is considerably different from natural soil materials and natural waters. Consequently, many conventional methods for the collection and analysis of natural soils and waters are not directly applicable to tailings. Secondly, there is a wide range in the physical and chemical nature of uranium tailings. The composition of the ore, the milling process, the nature of tailings depositon, and effluent treatment vary considerably and are highly site-specific. Therefore, the definition and implementation of sampling programs for uranium tailings disposal sites require considerable evaluation, and often innovation, to ensure that appropriate sampling and analysis methods are used which provide the flexibility to take into account site-specific considerations. The following chapters describe the objective and scope of a sampling program, preliminary data collection, and the procedures for sampling of tailings solids, surface water and seepage, tailings pore-water, and wind-blown dust and radon

Uranium in drinking water. A simple determination of uranium (VI) according to DIN standard 38406-17

International Nuclear Information System (INIS)

Haug, Sandro

2009-01-01

The number of reports on uranium loads in tap water and drinking water increases. Already for years, the organization Foodwatch e.V. (Berlin, Federal Republic of Germany) warns about to high concentrations of uranium in tap water. So far, only a limit value for mineral water exists in the Mineral Water Regulation which is suitable for the production of infant diet. This limit value amounts 2 microgram per litre. Temporarily, also in the policy a national limit value for uranium in drinking water is introduced. The Federal Office for Environment Protection (Dessau, FRG) designates a value of ten microgram uranium per litre of drinking water and mineral water as an approximate value. The effective control of water quality presupposes high-performance, simple and economical analysis methods. A particularly well suitable measuring technique for the determination of uranium(VI) in groundwater, raw water and drinking water is the voltammetry. In the last years, a national standard was compiled based on this measuring technique: DIN standard 38406-17

Estimation of rare earth elements in uranium matrix after solvent extraction of uranium as uranium-antipyrine-anion complex using chloroform as solvent

International Nuclear Information System (INIS)

Bose, Roopa; Murthy, D.S.R.; Malhotra, R.K.

1999-01-01

The neutron economy in a nuclear reactor dictates the occurrence of neutron absorbers at very low levels. Hence the determination of lanthanides especially Sm, Eu, Gd and Dy is one of the most difficult and complicated analytical tasks particularly in high uranium matrix. Solvent extraction is a potent and versatile technique for the separation of lanthanides. The systems generally used for lanthanide extraction are TBP-nitrate, TBP-chloride, TBP-thiocyanate TOPO, DEHPA-nitrate etc. However, these methods of extraction of lanthanides fail to give a clear cut separation for their determination from uranium matrix. Hence analytical procedures have been standardised for extraction of uranium matrix into the organic phase leaving lanthanides unextracted in the aqueous phase. In this direction Cyanex-923 a mixture of 4 trialkyl phosphine oxides, TBP- TOPO and trioctylamine in xylene have been used for extraction of uranium and consequent determination of lanthanides by ICP-AES in the aqueous phase. In this paper the authors have investigated uranium -antipyrine -anion, a different combination other than the well known phosphine oxides and tertiary amines for extraction of uranium

A high charge state heavy ion beam source for heavy ion fusion

International Nuclear Information System (INIS)

Eylon, S.; Henestroza, E.

1996-01-01

A high current, low emittance, high charge state heavy ion beam source is being developed. This is designed to deliver a heavy ion fusion (HIF) driver accelerator scale beam. Using a high charge state beam in a driver accelerator for HIF may increase the acceleration efficiency, leading to a reduction in the driver accelerator size and cost. The proposed source system, which consists of a gas beam electron stripper followed by a high charge state beam separator, can be added to existing single charge state, low emittance, high brightness ion sources and injectors. We shall report on the source physics design using 3D beam simulations and experimental feasibility study results using a neutral gas stripper and a beam separator at the exit of the LBL 2 MV injector. (orig.)

Uranium in Canada

International Nuclear Information System (INIS)

1989-01-01

In 1988 Canada's five uranium producers reported output of concentrate containing a record 12,470 metric tons of uranium (tU), or about one third of total Western world production. Shipments exceeded 13,200 tU, valued at $Cdn 1.1 billion. Most of Canada's uranium output is available for export for peaceful purposes, as domestic requirements represent about 15 percent of production. The six uranium marketers signed new sales contracts for over 11,000 tU, mostly destined for the United States. Annual exports peaked in 1987 at 12,790 tU, falling back to 10,430 tU in 1988. Forward domestic and export contract commitments were more than 70,000 tU and 60,000 tU, respectively, as of early 1989. The uranium industry in Canada was restructured and consolidated by merger and acquisition, including the formation of Cameco. Three uranium projects were also advanced. The Athabasca Basin is the primary target for the discovery of high-grade low-cost uranium deposits. Discovery of new reserves in 1987 and 1988 did not fully replace the record output over the two-year period. The estimate of overall resources as of January 1989 was down by 4 percent from January 1987 to a total (measured, indicated and inferred) of 544,000 tU. Exploration expenditures reached $Cdn 37 million in 1987 and $59 million in 1988, due largely to the test mining programs at the Cigar Lake and Midwest projects in Saskatchewan. Spot market prices fell to all-time lows from 1987 to mid-1989, and there is little sign of relief. Canadian uranium production capability could fall below 12,000 tU before the late 1990s; however, should market conditions warrant output could be increased beyond 15,000 tU. Canada's known uranium resources are more than sufficient to meet the 30-year fuel requirements of those reactors in Canada that are now or are expected to be in service by the late 1990s. There is significant potential for discovering additional uranium resources. Canada's uranium production is equivalent, in

Determination of uranium in natural waters and high-purity aluminum by flow-injection on-line preconcentration and ICP-MS detection

International Nuclear Information System (INIS)

Seki, Tatsuya; Oguma, Koichi

2004-01-01

A flow injection method has been developed for the determination of uranium is natural waters and high-purity aluminum by use of on-line preconcentration on a U/TEVA TM column and ICP-MS detection. The sample solution prepared as a nitric acid solution in 3 mol l -1 was passed through the U/TEVA TM column to collect uranium and uranium adsorbed was eluted with 0.1 mol l -1 nitric acid. The effluent was introduced directly into the nebulizer of the ICP-MS and 238 U was measured. The detection limit, calculated as 3-times the standard deviation of the background noise, was 3pg and the sample throughput was about 10 per hour. The proposed method was successfully applied to the determination of uranium in river-water reference materials, a seawater reference material and high-purity aluminum reference materials. (author)

Interaction of Uranium with Bacterial Cell Surfaces: Inferences from Phosphatase-Mediated Uranium Precipitation

Science.gov (United States)

Kulkarni, Sayali; Misra, Chitra Seetharam; Gupta, Alka; Ballal, Anand

2016-01-01

ABSTRACT Deinococcus radiodurans and Escherichia coli expressing either PhoN, a periplasmic acid phosphatase, or PhoK, an extracellular alkaline phosphatase, were evaluated for uranium (U) bioprecipitation under two specific geochemical conditions (GCs): (i) a carbonate-deficient condition at near-neutral pH (GC1), and (ii) a carbonate-abundant condition at alkaline pH (GC2). Transmission electron microscopy revealed that recombinant cells expressing PhoN/PhoK formed cell-associated uranyl phosphate precipitate under GC1, whereas the same cells displayed extracellular precipitation under GC2. These results implied that the cell-bound or extracellular location of the precipitate was governed by the uranyl species prevalent at that particular GC, rather than the location of phosphatase. MINTEQ modeling predicted the formation of predominantly positively charged uranium hydroxide ions under GC1 and negatively charged uranyl carbonate-hydroxide complexes under GC2. Both microbes adsorbed 6- to 10-fold more U under GC1 than under GC2, suggesting that higher biosorption of U to the bacterial cell surface under GC1 may lead to cell-associated U precipitation. In contrast, at alkaline pH and in the presence of excess carbonate under GC2, poor biosorption of negatively charged uranyl carbonate complexes on the cell surface might have resulted in extracellular precipitation. The toxicity of U observed under GC1 being higher than that under GC2 could also be attributed to the preferential adsorption of U on cell surfaces under GC1. This work provides a vivid description of the interaction of U complexes with bacterial cells. The findings have implications for the toxicity of various U species and for developing biological aqueous effluent waste treatment strategies. IMPORTANCE The present study provides illustrative insights into the interaction of uranium (U) complexes with recombinant bacterial cells overexpressing phosphatases. This work demonstrates the effects of aqueous

Uranium chemistry: significant advances

International Nuclear Information System (INIS)

Mazzanti, M.

2011-01-01

The author reviews recent progress in uranium chemistry achieved in CEA laboratories. Like its neighbors in the Mendeleev chart uranium undergoes hydrolysis, oxidation and disproportionation reactions which make the chemistry of these species in water highly complex. The study of the chemistry of uranium in an anhydrous medium has led to correlate the structural and electronic differences observed in the interaction of uranium(III) and the lanthanides(III) with nitrogen or sulfur molecules and the effectiveness of these molecules in An(III)/Ln(III) separation via liquid-liquid extraction. Recent work on the redox reactivity of trivalent uranium U(III) in an organic medium with molecules such as water or an azide ion (N 3 - ) in stoichiometric quantities, led to extremely interesting uranium aggregates particular those involved in actinide migration in the environment or in aggregation problems in the fuel processing cycle. Another significant advance was the discovery of a compound containing the uranyl ion with a degree of oxidation (V) UO 2 + , obtained by oxidation of uranium(III). Recently chemists have succeeded in blocking the disproportionation reaction of uranyl(V) and in stabilizing polymetallic complexes of uranyl(V), opening the way to to a systematic study of the reactivity and the electronic and magnetic properties of uranyl(V) compounds. (A.C.)

The interactions of high-energy, highly charged Xe ions with buckyballs

International Nuclear Information System (INIS)

Ali, R.; Berry, H.G.; Cheng, S.

1994-01-01

Ionization and fragmentation have been measured for C 60 molecules bombarded by highly charged (up to 35+) xenon ions with energies ranging up to 625 MeV. The observed mass distribution of positively charged fragments is explained in terms of a theoretical model indicating that the total interaction cross section contains roughly equal contributions from (a) excitation of the giant plasmon resonance, and (b) large-energy-transfer processes that lead to multiple fragmentation of the molecule. Preliminary results of measurements on VUV photons emitted in these interactions are also presented

Why jurisdiction and uranium deposit type are essential considerations for exploration and mining of uranium

International Nuclear Information System (INIS)

Miller, D.

2014-01-01

Uranium is a relatively abundant element, being 25 times more common than silver, and having the same crustal abundance as tin. Economically minable uranium grades vary greatly, from a low of 0.01% U to over 20% U. What are the factors that allow mining of these very low grade ores that are only 50 times background concentrations? Why don’t the high grade deposits of the world exclusively supply all of the worlds newly mined uranium needs? There are two main reasons that the high grade deposits of the world do not exclusively supply all of the worlds newly mined uranium needs: 1) jurisdictional issues, the favorability or lack thereof of governmental policies where the deposit is located and the delays caused by an ineffective or corrupt policy and 2) the deposit type, which has a great influence on the recovery cost of the uranium. The quality of a deposit can override more difficult political jurisdictions if recovery of the investment occurs quickly and in an environmentally friendly way.

Uranium leaching analysis (IAEA method) and total uranium determination in caldasite by the fluorometric method

International Nuclear Information System (INIS)

Sardela, I.A.; Fujimori, K.

1980-10-01

Caldasite is a radioactive mineral known mostly for its high radioactive content (U and Th). It is found only at the Pocos de Caldas Alkaline Complex, States of Minas Gerais. Samples colected at Campos do Serrote, Taquari and Brigrada located in the alkaline complex were submitted to the fluorometric method of uranium analysis. The results show a good precision and close agreement with those obtained with gamma ray spectroscopy. IAEA uranium leaching analysis has also been applied to this mineral, but only 0,4% of the total content was dissolved. The uranium leaching was more intense on the samples that have smaller equivalent uranium than total uranium and it may be attributed to a higher range Rn gas escape from this mineral. (Author) [pt

Chlorination separation of uranium, thorium, and radium from low-grade ores

International Nuclear Information System (INIS)

Sastri, V.S.; Perumareddi, J.R.

1995-01-01

Low-temperature chlorination of low-grade uranium ores containing uranium in the 0.02 to 0.06% range, thorium in the 0.036 to 0.12% range, and radium in the 70 to 200 pci/g range resulted in the extraction of >90% of the constituents. The residue left after chlorination was found to be innocuous and suitable for disposal as a waste acceptable to the environment. Use of sodium chloride in the charge was useful in reducing the chlorination temperature and in the formation of nonvolatile anionic chloro complexes of the metal ions in the ore

Department of Energy depleted uranium recycle

International Nuclear Information System (INIS)

Kosinski, F.E.; Butturini, W.G.; Kurtz, J.J.

1994-01-01

With its strategic supply of depleted uranium, the Department of Energy is studying reuse of the material in nuclear radiation shields, military hardware, and commercial applications. the study is expected to warrant a more detailed uranium recycle plan which would include consideration of a demonstration program and a program implementation decision. Such a program, if implemented, would become the largest nuclear material recycle program in the history of the Department of Energy. The bulk of the current inventory of depleted uranium is stored in 14-ton cylinders in the form of solid uranium hexafluoride (UF 6 ). The radioactive 235 U content has been reduced to a concentration of 0.2% to 0.4%. Present estimates indicate there are about 55,000 UF 6 -filled cylinders in inventory and planned operations will provide another 2,500 cylinders of depleted uranium each year. The United States government, under the auspices of the Department of Energy, considers the depleted uranium a highly-refined strategic resource of significant value. A possible utilization of a large portion of the depleted uranium inventory is as radiation shielding for spent reactor fuels and high-level radioactive waste. To this end, the Department of Energy study to-date has included a preliminary technical review to ascertain DOE chemical forms useful for commercial products. The presentation summarized the information including preliminary cost estimates. The status of commercial uranium processing is discussed. With a shrinking market, the number of chemical conversion and fabrication plants is reduced; however, the commercial capability does exist for chemical conversion of the UF 6 to the metal form and for the fabrication of uranium radiation shields and other uranium products. Department of Energy facilities no longer possess a capability for depleted uranium chemical conversion

Granite-related hypothermal uranium mineralization in South China

International Nuclear Information System (INIS)

Liu, X.; Wu, J.; Pan, J.; Zhu, M.

2014-01-01

As one of the important geological types, granite-related uranium deposits account for about 29% of the total discovered natural uranium resources in China. Most of the granite-related uranium deposits located in Taoshan - Zhuguang uranium metallogenic belt, South China. In addition to the typical pitchblende vein-type uranium mineralization of epithermal metallogenic system, a new type of granite-related uranium mineralization with characteristics of hypothermal matallogenic system was discovered in South China by current studies. However, hypothermal is contact thermal to epithermal mineralization, and not the conventional intrusive high temperature mineralization. Hypothermal uranium mineralization is presented by disseminated uraninite or pitchblende stockwork in fissures in granites normally with extensive alkaline alteration. The high temperature mineral assemblage of uraninite associate with scheelite and tourmaline was identified in hypothermal uranium mineralization. Fluid inclusion studies on this type mineralization indicated the middle to high temperature (>250℃) mineralization with the mixing evidence of ore forming solution derived from deep level, and the boiling and mixing of ore forming solution are regarded as the dominant mineralization mechanism for the precipitating of uranium. In contrast to the mineralization ages of 67 Ma to 87 Ma for typical pitchblende vein mineralization of epithermal metallogenic system, the mineralization age is older than 100 Ma for hypothermal uranium mineralization in granite. In the Shituling deposit, Xiazhuang uranium ore field, uraninite and pitchblende micro veins with extensive potassic alteration, chloritization and sericitization are hosted in fissures of Indo-Chinese epoch granites with the uranium mineralization age of 130 Ma to 138 Ma with a mineralization temperature of 290℃ to 330℃ indicated. Other examples sharing the similar characters of hypothermal uranium mineralization have been recognized in

Uranium ... long-term confidence

International Nuclear Information System (INIS)

Anon.

1983-01-01

Half way through 1983 the outlook for the world's uranium producers was far from bright if one takes a short term view. The readily accessible facts present a gloomy picture. The spot prices of uranium over the past few years decreased from a high of $42-$43/lb to a low of $17 in 1982. It now hovers between $23 and $24. the contract prices negotiated between producers and consumers are not so accessible but they do not reflect the spot price. The reasons why contractual uranium prices do not follow the usual dictates of supply and demand are related to the position in which uranium and associated power industries find themselves. There is public reaction with strong emotional overtones as well as much reduced expectations about the electric power needs of the world. Furthermore the supply of uranium is not guaranteed despite present over production. However the people in the industry, taking the medium- and long-term view, are not despondent

Sintering of uranium oxide of high specific surface area

International Nuclear Information System (INIS)

Bel, Alain; Francois, Bernard; Delmas, Roger; Caillat, Roger

1959-01-01

The extent to which a uranium oxide powder deriving from ammonium uranate or uranium peroxide lends itself to the sintering process depends largely on its specific surface area. When this is greater than 5 m 2 / g there is an optimum temperature for sintering in hydrogen. This temperature becomes less as the specific area of the powder is greater. Reprint of a paper published in Comptes rendus des seances de l'Academie des Sciences, t. 249, p. 1045-1047, sitting of 21 September 1959 [fr

A spectroscopic study of uranium(VI) interaction with magnetite

International Nuclear Information System (INIS)

El Aamrani, S.; Gimenez, J.; Rovira, M.; Seco, F.; Grive, M.; Bruno, J.; Duro, L.; Pablo, J. de

2007-01-01

The uranium sorbed onto commercial magnetite has been characterized by using two different spectroscopic techniques such as X-ray photoelectron spectroscopy (XPS), and extended X-ray absorption fine structure (EXAFS). Magnetite samples have been put in contact with uranium(VI) solutions in conditions in which a high uranium uptake is expected. After several days, the magnetite surface has been analysed by XPS and EXAFS. The XPS results obtained are not conclusive regarding the uranium oxidation state in the magnetite surface. On the other hand, the results obtained with the EXAFS technique show that the uranium-magnetite sample spectrum has characteristics from both the UO 2 and schoepite spectra, e.g. a relatively high coordination number of equatorial oxygens and two axial oxygens, respectively. These results would indicate that the uranium sorbed onto magnetite would be a mixture of uranium(IV) and uranium(VI)

Contemporary Pollution Due Old Uranium Tails

International Nuclear Information System (INIS)

Hadjamberdiev, I.

2007-01-01

The areas of our study are uranium mining areas (with tails and dumps) Min-Kush, Kadji-Sai, Mailuu-Suu. These areas situated in different parts of Tien-Shan region. We study the content (and correlations among): level of uranium in environment, immune function and level, level in human teeth. It has been found: content of uranium in river water under tails about 2,0x10-5 gm/litter, and high level in drinking water too 2,0-4,0. Drying grass and flowers uranium content was 0,04-0,51x10-5 gm/gm, most high content were in Tacniatherum crinitum and Atgilops triuncialis. Lams tissues contain 0,005-2,44 mg/g in Min-Kush, 0,03-0,107, in Mailuu-Suu, and 0,001-0,048 mg/g in Kadji-Sai. Human teeth uranium content (Mailuu-Suu): in milk-teeth 0,481x10-6 gm/gm, in former miners 0,7684x10-6 gm/gm. Inhabitants of the area, which not working in uranium industry have 0,6876x10-6 gm/gm. There was low level of immune function (lymphocytes, IgI globulin, etc) in all three regions (in child, in adults, in uranium-mining worked people). There is no doubt of the positive correlations of uranium pollution of water (by underground infiltration from tails) on one hand and, on the other hand - a) grass, b) lambs body, c) human teeth, d) human immune function. Levels of uranium in teeth strictly depend on time of mining contact. (author)

Geochemical methods for identification of formations being prospective for uranium

International Nuclear Information System (INIS)

Zhukova, A.M.; Komarova, N.I.; Spiridonov, A.A.; Shor, G.M.

1985-01-01

Geochemical methods of uranium content evaluation in metamorphic, ultrametamorphic and sedimentary formations are considered. At that, the following four factors are of the highest importance: 1) average uranium content-geochemical background; 2) character of uranium distribution; 3) forms of uranium presence; 4) the value of thorium-uranium ratio. A complex of radiogeochemical criteria, favourable for uranium presence is formulated: high average background content of total and '' mobile''uranium and high value of variation coefficient (80-100% and above); low (approximately one or lower) thorium-uranium ratio; sharp increase in uranium concentration in accessory minerals. Radiogeochemical peculiarities of metamorphic and ultrametamorphic formations prospective for uranium are enumerated. The peculiarities condition specificity of geochemical prospecting methods. Prospecting methods first of all must be directed at the evaluation of radioelement distribution parameters and specification of the forms of their presence

Development of Advanced High Uranium Density Fuels for Light Water Reactors

Energy Technology Data Exchange (ETDEWEB)

Blanchard, James [Univ. of Wisconsin, Madison, WI (United States); Butt, Darryl [Boise State Univ., ID (United States); Meyer, Mitchell [Idaho National Lab. (INL), Idaho Falls, ID (United States); Xu, Peng [Westinghouse Electric Corporation, Pittsburgh, PA (United States)

2016-02-15

This work conducts basic materials research (fabrication, radiation resistance, thermal conductivity, and corrosion response) on U3Si2 and UN, two high uranium density fuel forms that have a high potential for success as advanced light water reactor (LWR) fuels. The outcome of this proposed work will serve as the basis for the development of advance LWR fuels, and utilization of such fuel forms can lead to the optimization of the fuel performance related plant operating limits such as power density, power ramp rate and cycle length.

The interactions of high-energy, highly-charged ions with fullerenes

International Nuclear Information System (INIS)

Ali, R.; Berry, H.G.; Cheng, S.

1996-01-01

In 1985, Robert Curl and Richard Smalley discovered a new form of carbon, the fullerene, C 60 , which consists of 60 carbon atoms in a closed cage resembling a soccer ball. In 1990, Kritschmer et al. were able to make macroscopic quantities of fullerenes. This has generated intense activity to study the properties of fullerenes. One area of research involves collisions between fullerenes and atoms, ions or electrons. In this paper we describe experiments involving interactions between fullerenes and highly charged ions in which the center-of-mass energies exceed those used in other work by several orders of magnitude. The high values of projectile velocity and charge state result in excitation and decay processes differing significantly from those seen in studies 3 at lower energies. Our results are discussed in terms of theoretical models analogous to those used in nuclear physics and this provides an interesting demonstration of the unity of physics

Return of 80% highly enriched uranium fresh fuel from Yugoslavia to Russia

International Nuclear Information System (INIS)

Pesic, M.; Sotic, O.; Subotic, K.; Hopwood, W. Jr; Moses, S.; Wander, T.; Smirnov, A.; Kanashov, B.; Eshcherkin, A.; Efarov, S.; Olivieri, C.; Loghin, N. E.

2003-01-01

The transport of almost 50 kg of highly enriched (80%) uranium (HEU), in the form of fresh TVR-S fuel elements, from the Vin a Institute of Nuclear Sciences, Yugoslavia, to the Russian Federation for uranium reprocessing was carried out in August 2002. This act was a contribution of the Government of the Federal Republics of Yugoslavia (now Serbia and Montenegro) to the world's joint efforts to prevent possible actions of terrorists against nuclear material that potentially would be usable for the production of nuclear weapons. Basic aspects of this complex operation, carried out mainly by transport teams of the Vinca Institute and of the Institute for Safe Transport of Nuclear Materials from Dimitrovgrad, Russian Federation, are described in this paper. A team of IAEA safety inspectors and experts from the DOE, USA, for transport and non-proliferation, supported the whole operation. (author)

Return of 80% highly enriched uranium fresh fuel from Yugoslavia to Russia

International Nuclear Information System (INIS)

Pesic, M.; Sotic, O.; Subotic, K.; Hopwood, W. Jr; Moses, S.; Wander, T.; Smirnov, A.; Kanashov, B.; Eshcherkin, A.; Efarov, S.; Olivieri, C.; Loghin, N. E.

2003-01-01

The transport of almost 50 kg of highly enriched (80%) uranium (HEU), in the form of fresh TVR-S fuel elements, from the Vinca Institute of Nuclear Sciences, Yugoslavia, to the Russian Federation for uranium reprocessing was carried out in August 2002. This act was a contribution of the Government of the Federal Republics of Yugoslavia (now Serbia and Montenegro) to the world's joint efforts to prevent possible actions of terrorists against nuclear material that potentially would be usable for the production of nuclear weapons. Basic aspects of this complex operation, carried out mainly by transport teams of the Vinca Institute and of the Institute for Safe Transport of Nuclear Materials from Dimitrovgrad, Russian Federation, are described in this paper. A team of IAEA safety inspectors and experts from the DOE, USA, for transport and non-proliferation, supported the whole operation. (author)

Assessment of undiscovered resources in calcrete uranium deposits, Southern High Plains region of Texas, New Mexico, and Oklahoma, 2017

Science.gov (United States)

Hall, Susan M.; Mihalasky, Mark J.; Van Gosen, Bradley S.

2017-11-14

The U.S. Geological Survey estimates a mean of 40 million pounds of in-place uranium oxide (U3O8) remaining as potential undiscovered resources in the Southern High Plains region of Texas, New Mexico, and Oklahoma. This estimate used a geology-based assessment method specific to calcrete uranium deposits.

Uranium and environment in Kazakstan

International Nuclear Information System (INIS)

Fyodorov, G.; Bayadilov, E.; Zhelnov, V.; Akhmetov, M.; Abakumov, A.

1997-01-01

Kazakstan's data on uranium as a state report has been included for the first time in the Red Book. Therefore the report contains two large themes presented in Suggested Topics for Papers: Country report, based on the 1995 NEA/IAEA Red Book Questionnaire and environmental impact regulations. Kazakstan is considered as one of the world leaders on uranium supply. In Kazakstan there are many well known types of deposits but the main one is the sandstone-rollfront type. That type is represented by the group of deposits of the Syr-Darya uranium ore province. Deposits of that type include that main part of uranium ore of the Republic of Kazakstan and supply almost all of its uranium mining. At the large three enterprises the uranium is extracted by underground leaching. The mining method of uranium extraction is stopped. Because of the poor development of nuclear energy, Kazakstan's need for uranium is not very high. Presence of a large amount of cheap and technological uranium ores allow the Republic to export uranium. There are plans to increase uranium mining and perhaps to establish new mining facilities including joint-ventures. More than 50 uranium deposits are known in Kazakstan. During prospecting and exploitation of these deposits a large amount of rad wastes in the form of ore dumps and tailings were generated. They have a substantial influence on the environment. Moreover, near the sandstone-rollfront type uranium deposits the large amount of underground water has been contaminated by radionuclides. Special investigation of this phenomenon is necessary. In Kazakstan there are the rad waste disposal conception and contaminated earth recultivation regulations. At present ''The Rad Wastes Management Law'' is submitted for approval. (author). 2 figs

Uranium's effects on bone integrity

International Nuclear Information System (INIS)

Souidi, Maamar; Wade-Gueye, Ndeye Marieme; Manens, Line; Blanchardon, Eric; Aigueperse, Jocelyne

2018-01-01

Uranium is a radioactive heavy metal naturally present in the environment. Its recent use in various civilian and military applications sometimes result in its release into the environment. After chronic ingestion, uranium accumulates in various organs, preferentially in bones. Several studies have shown that exposure to high concentrations of uranium affects bone growth. Little is known, however, about the effects of chronic exposure to low doses of uranium on bone, especially when ingested via drinking water, the main route by which the public is exposed to this radionuclide. This study examined the effects of chronic exposure to natural uranium through drinking water on bone integrity and bone turnover. Rats were contaminated with different concentrations of natural uranium (15, 10, and 40 mg / l) for 9 months. A high-resolution three-dimensional microtomography scanner was used for the first time to study uranium's impact on bone metabolism and thus on bone tissue integrity. After nine months of uranium exposure, micro-architecture analysis revealed that the cortical bone diameter of the femoral diaphysis of rats contaminated at a concentration of 40 mg/L of uranium had decreased significantly. In conclusion, our findings that chronic ingestion of uranium at low concentrations affects growth of cortical bone width suggests that it may affect bone strength. These results thus suggest the need to pay special attention to children during chronic low-dose exposure to this radionuclide. (authors)

Uranium exploration

International Nuclear Information System (INIS)

De Voto, R.H.

1984-01-01

This paper is a review of the methodology and technology that are currently being used in varying degrees in uranium exploration activities worldwide. Since uranium is ubiquitous and occurs in trace amounts (0.2 to 5 ppm) in virtually all rocks of the crust of the earth, exploration for uranium is essentially the search of geologic environments in which geologic processes have produced unusual concentrations of uranium. Since the level of concentration of uranium of economic interest is dependent on the present and future price of uranium, it is appropriate here to review briefly the economic realities of uranium-fueled power generation. (author)

Uranium

International Nuclear Information System (INIS)

1982-01-01

The development, prospecting, research, processing and marketing of South Africa's uranium industry and the national policies surrounding this industry form the headlines of this work. The geology of South Africa's uranium occurences and their positions, the processes used in the extraction of South Africa's uranium and the utilisation of uranium for power production as represented by the Koeberg nuclear power station near Cape Town are included in this publication

The uranium market prospects

International Nuclear Information System (INIS)

Lloyd, R.

1981-01-01

A historical analysis of the uranium market points out the cyclical nature of the market and suggests that the spot price, exploration levels, and mill capacity utilization rate are dependent on economic factors. An examination of the current uranium market suggests that the effects of the forecasted surplus supply, the diminishing returns in exploration and the long lead times and high costs of development may mean that future production levels are uncertain. The general prospects for the uranium industry are also uncertain because of barriers to trade, environmental regulations and public opinion. The paper concludes that by the use of long term contracts, appropriate inventory policy and greater discussion between producers and consumers the prospects for the uranium market can be made more certain and further imbalances in demand and supply can be avoided. (author)

Natural uranium

International Nuclear Information System (INIS)

Ammerich, Marc; Frot, Patricia; Gambini, Denis-Jean; Gauron, Christine; Moureaux, Patrick; Herbelet, Gilbert; Lahaye, Thierry; Pihet, Pascal; Rannou, Alain

2014-08-01

This sheet belongs to a collection which relates to the use of radionuclides essentially in unsealed sources. Its goal is to gather on a single document the most relevant information as well as the best prevention practices to be implemented. These sheets are made for the persons in charge of radiation protection: users, radioprotection-skill persons, labor physicians. Each sheet treats of: 1 - the radio-physical and biological properties; 2 - the main uses; 3 - the dosimetric parameters; 4 - the measurement; 5 - the protection means; 6 - the areas delimitation and monitoring; 7 - the personnel classification, training and monitoring; 8 - the effluents and wastes; 9 - the authorization and declaration administrative procedures; 10 - the transport; and 11 - the right conduct to adopt in case of incident or accident. This sheet deals specifically with natural uranium

Vacuum improvements for ultra high charge state ion acceleration

International Nuclear Information System (INIS)

Xie, Z.Q.; Lyneis, C.M.; Clark, D.J.; Guy, A.; Lundgren, S.A

1998-06-01

The installation of a second cryo panel has significantly improved the vacuum in the 88-Inch Cyclotron at Lawrence Berkeley National Laboratory. The neutral pressure in the extraction region decreased from 1.2 x 10 -6 down to about 7 x 10 -7 Torr. The vacuum improvement reduces beam loss from charge changing collisions and enhances the cyclotron beam transmission, especially for the high charge state heavy ions. Tests with improved vacuum show the cyclotron transmission increased more than 50% (from 5.7% to 9.0%) for a Xe 27+ at 603 MeV, more than doubled for a Bi 41+ beam (from 1.9% to 4.6%) at 904 MeV and tripled for a U 47+ beam (from 1.2% to 3.6%) at 1,115 MeV. At about 5 NeV/nucleon 92 enA (2.2 pnA) for Bi 41+ and 14 enA (0.3 pnA) for U 47+ were extracted ut of the 88-Inch Cyclotron Ion beams with charge states as high as U 64+ have been produced by the LBNL AECR-U ion source and accelerated through the cyclotron for the first time. The beam losses for a variety of ultra high charge state ions were measured as a function of cyclotron pressure and compared with the calculations from the existing models

Vacuum improvements for ultra high charge state ion acceleration

International Nuclear Information System (INIS)

Xie, Z.Q.; Lyneis, C.M.; Clark, D.J.; Guy, A.; Lundgren, S.A.

1999-01-01

The installation of a second cryo panel has significantly improved the vacuum in the 88-Inch Cyclotron at Lawrence Berkeley National Laboratory. The neutral pressure in the extraction region decreased from 1.2 x 10 -6 down to about 7 x 10 -7 Torr. The vacuum improvement reduces beam loss from charge changing collisions and enhances the cyclotron beam transmission, especially for the high charge state heavy ions. Tests with improved vacuum show the cyclotron transmission increased more than 50% (from 5.7% to 9.0%) for a Xe 27+ at 603 MeV, more than doubled for a Bi 41+ beam (from 1.9% % to 4.6%) at 904 MeV and tripled for a U 47+ beam (from 1.2% to 3.6%) at 1115 MeV. At about 5 MeV/nucleon 92 enA (2.2 pnA) for Bi 41+ and 14 enA (0.3 pnA) for U 47+ were extracted out of the 88-Inch Cyclotron Ion beams with charge states as high as U 64+ have been produced by the LBNL AECR-U ion source and accelerated through the cyclotron for the first time. The beam losses for a variety of ultra high charge state ions were measured as a function of cyclotron pressure and compared with the calculations from the existing models. (authors)

31 CFR 540.315 - Uranium-235 (U235).

Science.gov (United States)

2010-07-01

... 31 Money and Finance: Treasury 3 2010-07-01 2010-07-01 false Uranium-235 (U235). 540.315 Section... FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY HIGHLY ENRICHED URANIUM (HEU) AGREEMENT ASSETS CONTROL REGULATIONS General Definitions § 540.315 Uranium-235 (U235). The term uranium-235 or U235 means the fissile...

Development of very high-density low-enriched uranium fuels

International Nuclear Information System (INIS)

Snelgrove, J.L.; Hofman, G.L.; Trybus, C.L.; Wiencek, T.C.

1997-02-01

The RERTR program has recently begun an aggressive effort to develop dispersion fuels for research and test reactors with uranium densities of 8 to 9 g U/cm 3 , based on the use of γ-stabilized uranium alloys. Fabrication development teams and facilities are being put into place and preparations for the first irradiation test are in progress. The first screening irradiations are expected to begin in late April 1997 and first results should be available by end of 1997. Discussions with potential international partners in fabrication development and irradiation testing have begun

Effect of pH and Pressure on Uranium Removal from Drinking Water Using NF/RO Membranes.

Science.gov (United States)

Schulte-Herbrüggen, Helfrid M A; Semião, Andrea J C; Chaurand, Perrine; Graham, Margaret C

2016-06-07

Groundwater is becoming an increasingly important drinking water source. However, the use of groundwater for potable purposes can lead to chronic human exposure to geogenic contaminants, for example, uranium. Nanofiltration (NF) and reverse osmosis (RO) processes are used for drinking water purification, and it is important to understand how contaminants interact with membranes since accumulation of contaminants to the membrane surface can lead to fouling, performance decline and possible breakthrough of contaminants. During the current study laboratory experiments were conducted using NF (TFC-SR2) and RO (BW30) membranes to establish the behavior of uranium across pH (3-10) and pressure (5-15 bar) ranges. The results showed that important determinants of uranium-membrane sorption interactions were (i) the uranium speciation (uranium species valence and size in relation to membrane surface charge and pore size) and (ii) concentration polarization, depending on the pH values. The results show that it is important to monitor sorption of uranium to membranes, which is controlled by pH and concentration polarization, and, if necessary, adjust those parameters controlling uranium sorption.

Current status and future prospects of uranium resources

International Nuclear Information System (INIS)

Kuronuma, Chosuke

1997-01-01

Uranium is contained in various things in natural world, for example, 3 ppm in granite and 3x10 -3 ppm in seawater. Uranium exists in the state of tetra, penta and hexa-valence in nature, and in oxidizing environment, it exists as uranyl radical of hexa-valence, forms soluble complexes, and easily moves with water. In reducing environment, it becomes insoluble state of tetra-valence and precipitates. This property of uranium is deeply related to the way of forming the deposit, and it is explained. The uranium resources of the recovery cost being 80 dollars per kg U or less are 2,120,000 t, and 60% of the total exists in Australia, Kazakstan and Canada. The cumulative production of uranium in the world from 1945 to 1995 was 1,810,000 t. Of the total production, 875,000 t was used for civil purpose, and 750,000 t was used for military purpose. The uranium deposits in Canada are very high quality, and produce 1/3 of the world uranium production. There are the inventories of 150,000-200,000 t U. The diversion of military high enriched uranium to civil purpose is reported. The state of uranium market, the prospect of demand and supply of uranium, and the exploration and development of uranium resources are described. (K.I.)

Computer modelling of the chemical speciation of caesium, uranium(VI) and neptunium(V) in human duodenal fluids under fasting conditions

International Nuclear Information System (INIS)

Jones, P.W.; Taylor, D.M.; Webb, L.M.; Williams, D.R.

2002-01-01

A model simulating the human duodenal contents under physiologically realistic, fasting conditions was developed using the joint expert speciation system (JESS) computer program and database and used to investigate the chemical speciation of caesium, uranium(VI) and neptunium(V). Over the pH range 5.0-9.0, and the concentration range 5x10 -15 -5x10 -5 mol dm -3 , caesium was predicted to occur predominantly as the absorbable free monovalent cation Cs + (∼95%) with species such as CsHPO 4 - and CsCl representing the remainder. The presence or absence of sulphate at 2.1x10 -3 mol dm -3 did not influence the predicted speciation. Uranium was predicted to be present entirely as a soluble, highly charged species, both in the absence and in the presence of sulphate. Between pH 5.0 and ∼6.5 the UO 2 H 2 (PO 4 ) 2 2- predominated, above this pH carbonate species, either UO 2 (CO 3 ) 4 6- or, possibly, UO 2 (CO 3 ) 5 8- . At pH 8.0, and in the presence of sulphate, neptunium(V) was predicted to exist solely as the tetrasulphate species, whilst in the absence of sulphate, an array of negatively charged soluble carbonate species predominated. Studies over the pH range 5.0-9.0 predicted the formation of a spectrum of negatively charged carbonate and phosphate species, ∼40% of the total neptunium was predicted to be present as the electrically net-neutral species NpO 2 HCO 3 at pH6.0, ∼20% at pH 7.0, ∼10% at pH 7.5 and ∼1% at pH 8.0. The observed speciation patterns of uranium and neptunium did not change over the concentration range 5x10 -15 -5x10 -5 mol dm -3 and no solid species were predicted to occur under the conditions simulated. Whether the predicted electrically net-neutral neptunium species or the uranium pentacarbonate species do actually occur under true physiological conditions remains to be established. The observed speciation patterns for caesium and uranium are consistent with the observed absorption of these elements by humans; however, the

National uranium project - an initiative to generate national database on uranium in drinking water of the country

International Nuclear Information System (INIS)

Sahoo, S.K.; Tripathi, R.M.; Jha, V.N.; Kumar, Ajay; Patra, A.C.; Vinod Kumar, A.

2018-01-01

Uranium is a naturally occurring lithophilic heavy element found in earth crust since inception of the earth. It is present naturally in all rock and soil and the concentration depends on geological formation and local geology. Groundwater interact with the host rocks and the wet weathering process facilitate the solubility of uranium in groundwater. The concentration of uranium in groundwater is influenced by geo-chemical parameters such as host rock characteristics and pH, Eh, ORP, ligands, etc. of the interacting water medium. Uranium is a radioactive element of low specific activity (25 Bq/mg) having both chemical and radiological toxicity but its chemical toxicity supersede the radio-toxicity. After a reporting of high uranium content in drinking water of Punjab, BARC has taken a pro-active initiative to generate a national database on uranium in drinking water in all the districts of India under National Uranium Project (NUP)

Use of minor uranium isotope measurements as an aid in safeguarding a uranium enrichment cascade

International Nuclear Information System (INIS)

Levin, S.A.; Blumkin, S.; Von Halle, E.

1979-01-01

Surveillance and containment, which are indispensable supporting measures for material accountability, do not provide those charged with safeguarding an installation with the assurance beyond the shadow of a doubt that all the input and output uranium will in fact be measured. Those who are concerned with developing non-intrusive techniques for safeguarding uranium enrichment plants under the Nuclear Non-Proliferation Treaty have perceived the possibility that data on the minor uranium isotope concentrations in an enrichment cascade withdrawal and feed streams may provide a means either to corroborate or to contradict the material accountability results. A basic theoretical study has been conducted to determine whether complete isotopic measurements on enrichment cascade streams may be useful for safeguards purposes. The results of the calculations made to determine the behaviour of the minor uranium isotopes ( 234 U and 236 U) in separation cascades, and the results of three plant tests made to substantiate the validity of the calculations, are reviewed briefly. Based on the fact that the 234 U and 236 U concentrations relative to that of 235 U in cascade withdrawal streams reflect the cascade flow-sheet, the authors conclude that the use of the minor isotope concentration measurements (MIST) in cascade withdrawal streams is a potentially valuable adjunct to material accounting for safeguarding a 235 U enrichment cascade. A characteristic of MIST, which qualifies it particularly for safeguards application under the NPT, is the fact that its use is entirely non-intrusive with regard to process technology and proprietary information. The usefulness of MIST and how it may be applied are discussed briefly. (author)

Measurement of highly enriched uranium metal buttons with the high-level neutron coincidence counter operating in the active mode

International Nuclear Information System (INIS)

Foley, J.E.

1980-10-01

The portable High-Level Neutron Coincidence Counter is used in the active mode with the addition of AmLi neutron sources to assay the 235 U content of highly enriched metal pieces or buttons. It is concluded that the portable instrument is a practical instrument for assaying uranium metal buttons with masses in the range 1.5 to 4 kg

Uranium removal from soils: An overview from the Uranium in Soils Integrated Demonstration program

International Nuclear Information System (INIS)

Francis, C.W.; Brainard, J.R.; York, D.A.; Chaiko, D.J.; Matthern, G.

1994-01-01

An integrated approach to remove uranium from uranium-contaminated soils is being conducted by four of the US Department of Energy national laboratories. In this approach, managed through the Uranium in Soils Integrated Demonstration program at the Fernald Environmental Management Project, Fernald, Ohio, these laboratories are developing processes that selectively remove uranium from soil without seriously degrading the soil's physicochemical characteristics or generating waste that is difficult to manage or dispose of. These processes include traditional uranium extractions that use carbonate as well as some nontraditional extraction techniques that use citric acid and complex organic chelating agents such as naturally occurring microbial siderophores. A bench-scale engineering design for heap leaching; a process that uses carbonate leaching media shows that >90% of the uranium can be removed from the Fernald soils. Other work involves amending soils with cultures of sulfur and ferrous oxidizing microbes or cultures of fungi whose role is to generate mycorrhiza that excrete strong complexers for uranium. Aqueous biphasic extraction, a physical separation technology, is also being evaluated because of its ability to segregate fine particulate, a fundamental requirement for soils containing high levels of silt and clay. Interactions among participating scientists have produced some significant progress not only in evaluating the feasibility of uranium removal but also in understanding some important technical aspects of the task

Uranium diphosphonates templated by interlayer organic amines

International Nuclear Information System (INIS)

Nelson, Anna-Gay D.; Alekseev, Evgeny V.; Albrecht-Schmitt, Thomas E.; Ewing, Rodney C.

2013-01-01

The hydrothermal treatment of uranium trioxide and methylenediphosphonic acid with a variety of amines (2,2-dipyridyl, triethylenediamine, ethylenediamine, and 1,10-phenanthroline) at 200 °C results in the crystallization of a series of layered uranium diphosphonate compounds, [C 10 H 9 N 2 ]{UO 2 (H 2 O)[CH 2 (PO 3 )(PO 3 H)]} (Ubip2), [C 6 H 14 N 2 ]{(UO 2 ) 2 [CH 2 (PO 3 )(PO 3 H)] 2 ·2H 2 O} (UDAB), [C 2 H 10 N 2 ] 2 {(UO 2 ) 2 (H 2 O) 2 [CH 2 (PO 3 ) 2 ] 2 ·0.5H 2 O} (Uethyl), and [C 12 H 9 N 2 ]{UO 2 (H 2 O)[CH 2 (PO 3 )(PO 3 H)]} (Uphen). The crystal structures of the compounds are based on UO 7 units linked by methylenediphosphonate molecules to form two-dimensional anionic sheets in Ubip2 and UDAB, and one-dimensional anionic chains in Uethyl and Uphen, which are charge balanced by protonated amine molecules. Interaction of the amine molecules with phosphonate oxygens and water molecules results in extensive hydrogen bonding in the interlayer. These amine molecules serve both as structure-directing agents and charge-balancing cations for the anionic uranium phosphonate sheets and chains in the formation of the different coordination geometries and topologies of each structure. Reported herein are the syntheses, structural and spectroscopic characterization of the synthesized compounds. - Graphical abstract: The Raman spectra of the synthesized compounds and an illustration of the stacking of the layers with the diprotonated triethylenediamine molecules in [C 6 H 14 N 2 ]{(UO 2 ) 2 [CH 2 (PO 3 )(PO 3 H)] 2 ·2H 2 O} UDAB. Solvent water molecules are removed for clarity. The corresponding Raman spectra for the complexes synthesized is also shown. The structure is constructed from UO 7 pentagonal bipyramids (yellow), oxygen=red, phosphorus=magenta, carbon=black, and nitrogen=blue. Highlights: ► Organic amines act both as charge-balancing and as structure-directing agents. ► Extensive hydrogen bonding interactions with solvent water molecules and amines

Production of highly charged ion beams from ECR ion sources

International Nuclear Information System (INIS)

Xie, Z.Q.

1997-09-01

Electron Cyclotron Resonance (ECR) ion source development has progressed with multiple-frequency plasma heating, higher mirror magnetic fields and better technique to provide extra cold electrons. Such techniques greatly enhance the production of highly charged ions from ECR ion sources. So far at cw mode operation, up to 300 eμA of O 7+ and 1.15 emA of O 6+ , more than 100 eμA of intermediate heavy ions for charge states up to Ar 13+ , Ca 13+ , Fe 13+ , Co 14+ and Kr 18+ , and tens of eμA of heavy ions with charge states to Kr 26+ , Xe 28+ , Au 35+ , Bi 34+ and U 34+ have been produced from ECR ion sources. At an intensity of at least 1 eμA, the maximum charge state available for the heavy ions are Xe 36+ , Au 46+ , Bi 47+ and U 48+ . An order of magnitude enhancement for fully stripped argon ions (I ≥ 60 enA) also has been achieved. This article will review the ECR ion source progress and discuss key requirement for ECR ion sources to produce the highly charged ion beams

Uranium

International Nuclear Information System (INIS)

Mackay, G.A.

1978-01-01

The author discusses the contribution made by various energy sources in the production of electricity. Estimates are made of the future nuclear contribution, the future demand for uranium and future sales of Australian uranium. Nuclear power growth in the United States, Japan and Western Europe is discussed. The present status of the six major Australian uranium deposits (Ranger, Jabiluka, Nabarlek, Koongarra, Yeelerrie and Beverley) is given. Australian legislation relevant to the uranium mining industry is also outlined

Czechoslovak uranium

International Nuclear Information System (INIS)

Pluskal, O.

1992-01-01

Data and knowledge related to the prospecting, mining, processing and export of uranium ores in Czechoslovakia are presented. In the years between 1945 and January 1, 1991, 98,461.1 t of uranium were extracted. In the period 1965-1990 the uranium industry was subsidized from the state budget to a total of 38.5 billion CSK. The subsidies were put into extraction, investments and geologic prospecting; the latter was at first, ie. till 1960 financed by the former USSR, later on the two parties shared costs on a 1:1 basis. Since 1981 the prospecting has been entirely financed from the Czechoslovak state budget. On Czechoslovak territory uranium has been extracted from deposits which may be classified as vein-type deposits, deposits in uranium-bearing sandstones and deposits connected with weathering processes. The future of mining, however, is almost exclusively being connected with deposits in uranium-bearing sandstones. A brief description and characteristic is given of all uranium deposits on Czechoslovak territory, and the organization of uranium mining in Czechoslovakia is described as is the approach used in the world to evaluate uranium deposits; uranium prices and actual resources are also given. (Z.S.) 3 figs

Worldwide developments in uranium

International Nuclear Information System (INIS)

Hoellen, E.E.

1987-01-01

World uranium production will continue to change in most major producing nations. Canadian production will increase and will be increasingly dominated by western producers as eastern Canadian high-cost production declines. Australian production will increase as major projects come into operation before 2000. US production will stabilize through the end of the century. South African production will be dependent upon the worldwide support for economic sanctions. China's entry into the world market injects yet another variable into the already cloudy supply picture. Many risks and uncertainties will face uranium producers through the 1980s. Recognizing that the uranium industry is not a fast-growing market, many existing and potential producers are seeking alternate investment courses, causing a restructuring of the world uranium production industry in ways not anticipated even a few years ago. During the restructuring process, world uranium production will most likely continue to exceed uranium consumption, resulting in a further buildup of world uranium inventories. Inventory sales will continue to redistribute this material. As inventory selling runs its course, users will turn to normal sources of supply, stimulating additional production to meet needs. Stimulation in the form of higher prices will be determined by how fast producers are willing and able to return to the market. Production costs are expected to have an increasing impact as it has become apparent that uranium resources are large in comparison to projected consumption. Conversely, security-of-supply issues have seemed to be of decreasing magnitude as Canada, Australia, and other non-US producers continue to meet delivery commitments

Uranium in Niger; L'uranium au Niger

Energy Technology Data Exchange (ETDEWEB)

Gabelmann, E

1978-03-15

This document presents government policy in the enhancement of uranium resources, existing mining companies and their productions, exploitation projects and economical outcome related to the uranium mining and auxiliary activities. [French] Le document presente la politique de l'Etat dans le cadre de la mise en valeur des ressources d'uranium, les societes minieres existantes et leurs productions, les projets d'exploitation d'uranium et les retombees economiques liees aux activites uraniferes et connexes.

Salt Separation from Uranium Deposits in Integrated Crucible

Energy Technology Data Exchange (ETDEWEB)

Kwon, S. W.; Park, K. M.; Chang, J. H.; Kim, J. G.; Park, S. B. [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2014-05-15

The solid cathode processing is necessary to separate the salt from the cathode since the uranium deposit in a solid cathode contains electrolyte salt. A physical separation process, such as distillation separation, is more attractive than a chemical or dissolution process because physical processes generate much less secondary process. Distillation process was employed for the cathode processsing due to the advantages of minimal generation of secondary waste, compact unit process, simple and low cost equipment. The basis for vacuum distillation separation is the difference in vapor pressures between salt and uranium. A solid cathode deposit is heated in a heating region and salt vaporizes, while non-volatile uranium remains behind. It is very important to increase the throughput of the salt separation system due to the high uranium content of spent nuclear fuel and high salt fraction of uranium dendrites. The evaporation rate of the LiCl-KCl eutectic salt in vacuum distiller is not so high to come up with the generation capacity of uranium dendrites in electro-refiner. Therefore, wide evaporation area or high distillation temperature is necessary for the successful salt separation. The adhered salt in the uranium deposits was removed successfully. The salt content in the deposits was below 0.1 wt% after the sequential operation of the liquid salt separation - salt distillation.

Heap leaching for uranium

International Nuclear Information System (INIS)

1988-01-01

Denison Mines Ltd. is using two bacterial leaching processes to combat the high cost of extracting uranium from low grade ore in thin reefs. Both processes use thiobacillus ferro-oxidans, a bacterium that employs the oxidation of ferrous iron and sulphur as its source of energy for growth. The first method is flood leaching, in which ore is subjected to successive flood, drain and rest cycles. The second, trickle leaching, uses sprinklers to douse the broken muck continuously with leaching solution. In areas where grades are too low to justify the expense of hauling the ore to the surface, the company is using this biological process underground to recover uranium. In 1987 Denison recovered 840 000 lb of uranium through bacterial heap leaching. It plans to have biological in-place leaching contribute 25% of the total uranium production by 1990. (fig.)

Resonance charge exchange mechanism at high and moderate energies

International Nuclear Information System (INIS)

Bogdanov, A.V.; Gevorkyan, A.S.

1984-01-01

Charge exchange mechanisms at high and medium energies are investigated, ta king the resonance charge exchange of a proton by an hydrogen atom as an example . It is established that there are two classical charge exchange mechanisms rel ated to direct proton knockout from the bound state and one quantum-mechanical mechanism corresponding to the electron tunnelling from one bound state to anoth er. The classical cross-section diverges for two of these mechanisms, and the quasiclassical scattering amplitude must be calculated on the base of a complex classical trajectory. Physical grounds for the choice of such trajectories are discussed and calculations of the Van Vleck determinant for these mechanisms a re presented. Contributions from different mechanisms to the total charge excha nge cross-section are analyzed. A comparison with experimental data and results of other authors is made

Near-threshold photoionization of hydrogenlike uranium studied in ion-atom collisions via the time-reversed process.

Science.gov (United States)

Stöhlker, T; Ma, X; Ludziejewski, T; Beyer, H F; Bosch, F; Brinzanescu, O; Dunford, R W; Eichler, J; Hagmann, S; Ichihara, A; Kozhuharov, C; Krämer, A; Liesen, D; Mokler, P H; Stachura, Z; Swiat, P; Warczak, A

2001-02-05

Radiative electron capture, the time-reversed photoionization process occurring in ion-atom collisions, provides presently the only access to photoionization studies for very highly charged ions. By applying the deceleration mode of the ESR storage ring, we studied this process in low-energy collisions of bare uranium ions with low- Z target atoms. This technique allows us to extend the current information about photoionization to much lower energies than those accessible for neutral heavy elements in the direct reaction channel. The results prove that for high- Z systems, higher-order multipole contributions and magnetic corrections persist even at energies close to the threshold.

Synthetic high-charge organomica: effect of the layer charge and alkyl chain length on the structure of the adsorbed surfactants.

Science.gov (United States)

Pazos, M Carolina; Castro, Miguel A; Orta, M Mar; Pavón, Esperanza; Valencia Rios, Jesús S; Alba, María D

2012-05-15

A family of organomicas was synthesized using synthetic swelling micas with high layer charge (Na(n)Si(8-n)Al(n)Mg(6)F(4)O(20)·XH(2)O, where n = 2, 3, and 4) exchanged with dodecylammonium and octadecylammonium cations. The molecular arrangement of the surfactant was elucidated on the basis on XRD patterns and DTA. The ordering conformation of the surfactant molecules into the interlayer space of micas was investigated by (13)C, (27)Al, and (29)Si MAS NMR. The arrangement of alkylammonium ions in these high-charge synthetic micas depends on the combined effects of the layer charge of the mica and the chain length of the cation. In the organomicas with dodecylammonium, a transition from a parallel layer to a bilayer-paraffin arrangement is observed when the layer charge of the mica increases. However, when octadecylammonium is the interlayer cation, the molecular arrangement of the surfactant was found to follow the bilayer-paraffin model for all values of layer charge. The amount of ordered conformation all-trans is directly proportional of layer charge.

Application of nanofiltration to the treatment of uranium mill effluents

International Nuclear Information System (INIS)

Macnaughton, S.J.; McCulloch, J.K.; Marshall, K.; Ring, R.J.

2002-01-01

Nanofiltration is widely used in water treatment due to the lower energy requirements and higher yields than reverse osmosis. Separation characteristics are dependent on both the molecular size and charge of the dissolved species in the feed solution as well as membrane properties. In this investigation the potential of nanofiltration to remove dissolved species from uranium mill effluent has been studied. The background behind the application is discussed and the results of the first testwork programme are presented. An initial screening of seventeen commercially available membranes was completed and it was found that uranium rejections of greater than 75% were consistently achieved. Selected membranes also showed potential for the separation of radium, sulfate and manganese. (author)

Development of very-high-density low-enriched uranium fuels

International Nuclear Information System (INIS)

Snegrove, J.L.; Hofmann, G.L.; Trybus, C.L.; Wiencek, T.C.

1997-01-01

The RERTR (=Reduced Enrichment for Research and Test Reactors) program has begun an aggressive effort to develop dispersion fuels for research and test reactors with uranium densities of 8 to 9 g U/cm 3 , based on the use of γ-stabilized uranium alloys. Fabrication development teams and facilities are being put into place, and preparations for the first irradiation test are in progress. The first screening irradiations are expected to begin in late April 1997 and the first results should be available by the end of 1997. Discussions with potential international partners in fabrication development and irradiation testing have begun. (author)

Uranium ores

International Nuclear Information System (INIS)

Poty, B.; Roux, J.

1998-01-01

The processing of uranium ores for uranium extraction and concentration is not much different than the processing of other metallic ores. However, thanks to its radioactive property, the prospecting of uranium ores can be performed using geophysical methods. Surface and sub-surface detection methods are a combination of radioactive measurement methods (radium, radon etc..) and classical mining and petroleum prospecting methods. Worldwide uranium prospecting has been more or less active during the last 50 years, but the rise of raw material and energy prices between 1970 and 1980 has incited several countries to develop their nuclear industry in order to diversify their resources and improve their energy independence. The result is a considerable increase of nuclear fuels demand between 1980 and 1990. This paper describes successively: the uranium prospecting methods (direct, indirect and methodology), the uranium deposits (economical definition, uranium ores, and deposits), the exploitation of uranium ores (use of radioactivity, radioprotection, effluents), the worldwide uranium resources (definition of the different categories and present day state of worldwide resources). (J.S.)

Successful trials on pressure leaching of uranium

International Nuclear Information System (INIS)

Pendreigh, R.

1978-01-01

High pressure leaching can increase uranium extraction from some low grade ores by ten per cent, and Anglo American Corporation's eighteen months of pilot plant tests point the way to commercial application. Interest in pressure leaching of uranium has been renewed with the recent increase in uranium and gold prices and costs of reagents

Production of Highly Charged Pharmaceutical Aerosols Using a New Aerosol Induction Charger.

Science.gov (United States)

Golshahi, Laleh; Longest, P Worth; Holbrook, Landon; Snead, Jessica; Hindle, Michael

2015-09-01

Properly charged particles can be used for effective lung targeting of pharmaceutical aerosols. The objective of this study was to characterize the performance of a new induction charger that operates with a mesh nebulizer for the production of highly charged submicrometer aerosols to bypass the mouth-throat and deliver clinically relevant doses of medications to the lungs. Variables of interest included combinations of model drug (albuterol sulfate) and charging excipient (NaCl) as well as strength of the charging field (1-5 kV/cm). Aerosol charge and size were measured using a modified electrical low pressure impactor system combined with high performance liquid chromatography. At the approximate mass median aerodynamic diameter (MMAD) of the aerosol (~0.4 μm), the induction charge on the particles was an order of magnitude above the field and diffusion charge limit. The nebulization rate was 439.3 ± 42.9 μl/min, which with a 0.1% w/v solution delivered 419.5 ± 34.2 μg of medication per minute. A new correlation was developed to predict particle charge produced by the induction charger. The combination of the aerosol induction charger and predictive correlations will allow for the practical generation and control of charged submicrometer aerosols for targeting deposition within the lungs.

Development of a high density fuel based on uranium-molybdenum alloys with high compatibility in high temperatures

International Nuclear Information System (INIS)

Oliveira, Fabio Branco Vaz de

2008-01-01

This work has as its objective the development of a high density and low enriched nuclear fuel based on the gamma-UMo alloys, for utilization where it is necessary satisfactory behavior in high temperatures, considering its utilization as dispersion. For its accomplishment, it was started from the analysis of the RERTR ('Reduced Enrichment for Research and Test Reactors') results and some theoretical works involving the fabrication of gamma-uranium metastable alloys. A ternary addition is proposed, supported by the properties of binary and ternary uranium alloys studied, having the objectives of the gamma stability enhancement and an ease to its powder fabrication. Alloys of uranium-molybdenum were prepared with 5 to 10% Mo addition, and 1 and 3% of ternary, over a gamma U7Mo binary base alloy. In all the steps of its preparation, the alloys were characterized with the traditional techniques, to the determination of its mechanical and structural properties. To provide a process for the alloys powder obtention, its behavior under hydrogen atmosphere were studied, in thermo analyser-thermo gravimeter equipment. Temperatures varied from the ambient up to 1000 deg C, and times from 15 minutes to 16 hours. The results validation were made in a semi-pilot scale, where 10 to 50 g of powders of some of the alloys studied were prepared, under static hydrogen atmosphere. Compatibility studies were conducted by the exposure of the alloys under oxygen and aluminum, to the verification of possible reactions by means of differential thermal analysis. The alloys were exposed to a constant heat up to 1000 deg C, and their performances were evaluated in terms of their reaction resistance. On the basis of the results, it was observed that ternary additions increases the temperatures of the reaction with aluminum and oxidation, in comparison with the gamma UMo binaries. A set of conditions to the hydration of the alloys were defined, more restrictive in terms of temperature, time and

Speciation of uranium in La{sub 2}Zr{sub 2}O{sub 7} pyrochlore by TRPLS

Energy Technology Data Exchange (ETDEWEB)

Mohapatra, M.; Rajeswari, B.; Hon, N. S.; Kadam, R. M., E-mail: rmkadam@barc.gov.in; Natarajan, V. [Radiochemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai-400085 (India)

2015-06-24

We discuss the speciation of uranium in lanthanum zirconate (La{sub 2}Zr{sub 2}O{sub 7} =LZO) pyrochlore ceramic prepared via a gel-combustion route. Uranium concentration in the pyrochlore was optimized to 2 mol%. XRD and SEM experiments were carried out to assess the phase and homogeneity of the prepared samples. Time resolved photoluminescence (TRPLS) investigations were carried out for understanding the species stabilized in the pyrochlore host. It was observed that, uranium exists as uranate ion (UO{sub 6}{sup 6−}) in the zirconate host where it replaces the ‘Zr’ ions at its regular site with surrounding defect centers created for charge compensation.

Prospects for the uranium market

International Nuclear Information System (INIS)

Murray, J.

1989-01-01

The Uranium Institute tries to find reasonably meaningful figures to identify the market for uranium. Reactor requirements are expected to rise by about 12000 tonnes by the year 2000. Actual uranium production has been lower than reactor requirements since the mid-1980s, but a high level of inventory was built up during years of excess production. United States buyers are less concerned about the future security of supplies of uranium than their European and Far Eastern counterparts. The absence of uranium resources results in inevitable dependence on the international market and higher concern with supply security. The higher the level of dependence on nuclear power, the greater becomes the penalty of failing to assure security of supply. The US utility regulatory system has discouraged long term coverage. US buyers are confident that production will respond in a timely fashion when demand calls for it

DEVELOPMENT OF HIGH-DENSITY U/AL DISPERSION PLATES FOR MO-99 PRODUCTION USING ATOMIZED URANIUM POWDER

Directory of Open Access Journals (Sweden)

HO JIN RYU

2013-12-01

Full Text Available Uranium metal particle dispersion plates have been proposed as targets for Molybdenum-99 (Mo-99 production to improve the radioisotope production efficiency of conventional low enriched uranium targets. In this study, uranium powder was produced by centrifugal atomization, and miniature target plates containing uranium particles in an aluminum matrix with uranium densities up to 9 g-U/cm3 were fabricated. Additional heat treatment was applied to convert the uranium particles into UAlx compounds by a chemical reaction of the uranium particles and aluminum matrix. Thus, these target plates can be treated with the same alkaline dissolution process that is used for conventional UAlx dispersion targets, while increasing the uranium density in the target plates

High ion charge states in a high-current, short-pulse, vacuum ARC ion sources

International Nuclear Information System (INIS)

Anders, A.; Brown, I.; MacGill, R.; Dickinson, M.

1996-01-01

Ions of the cathode material are formed at vacuum arc cathode spots and extracted by a grid system. The ion charge states (typically 1-4) depend on the cathode material and only little on the discharge current as long as the current is low. Here the authors report on experiments with short pulses (several μs) and high currents (several kA); this regime of operation is thus approaching a more vacuum spark-like regime. Mean ion charge states of up to 6.2 for tungsten and 3.7 for titanium have been measured, with the corresponding maximum charge states of up to 8+ and 6+, respectively. The results are discussed in terms of Saha calculations and freezing of the charge state distribution

High ion charge states in a high-current, short-pulse, vacuum arc ion source

International Nuclear Information System (INIS)

Anders, A.; Brown, I.; MacGill, R.; Dickinson, M.

1995-09-01

Ions of the cathode material are formed at vacuum arc cathode spots and extracted by a grid system. The ion charge states (typically 1--4) depend on the cathode material and only little on the discharge current as long as the current is low. Here the authors report on experiments with short pulses (several micros) and high currents (several kA); this regime of operation is thus approaching a more vacuum spark-like regime. Mean ion charge states of up to 6.2 for tungsten and 3.7 for titanium have been measured, with the corresponding maximum charge states of up to 8+ and 6+, respectively. The results are discussed in terms of Saha calculations and freezing of the charge state distribution

Copper Mountain, Wyoming, intermediate-grade uranium resource assessment project. Final report. National Uranium Resource Evaluation

International Nuclear Information System (INIS)

Madson, M.E.; Ludlam, J.R.; Fukui, L.M.

1982-11-01

Intermediate-grade uranium resources were delineated and estimated for Eocene and Precambrian host rock environments in the 39.64 mi 2 Copper Mountain, Wyoming, assessment area. Geologic reconnaissance and geochemical, geophysical, petrologic, borehole, and structural data were interpreted and used to develop a genetic model for uranium mineralization in these environments. Development of a structural scoring system and application of computer graphics in a high-confidence control area established the basis for estimations of uranium resources in the total assessment area. 8 figures, 5 tables

Baccharis Salicifolia development in the presence of high concentrations of uranium in the arid environment of San Marcos, Chihuahua

Energy Technology Data Exchange (ETDEWEB)

Luna P, M. Y.; Alarcon H, M. T.; Silva S, M.; Renteria V, M; Rodriguez V, M. A.; Herrera P, E.; Reyes C, M.; Montero C, M. E., E-mail: elena.montero@cimav.edu.m [Centro de Investigacion en Materiales Avanzados, S. C., Miguel de Cervantes 120, Complejo Industrial Chihuahua, 31109 Chihuahua (Mexico)

2011-02-15

In humid zones and marine environments the bio indicator contaminants by trace elements are well established. However, in arid zones it is more difficult to find these tools because there is less biodiversity. The objective of this paper was to analyze the behavior of the Baccharis salicifolia plant in areas with high uranium concentration in arid zones, to determine the characteristics of tolerance and possible use as a bio monitor for the presence of such contaminants. For this project a uraniferous zone was selected in San Marcos, located northwest of the City of Chihuahua. A total of 8 sampling points of the plant and soil were located here. Each sample was divided into the root and the stem and leaves to determine the specific activity of the uranium in both parts of the plant and its sediments. The determination of the specific activities of the total uranium in the samples was obtained by liquid scintillation with alpha-beta separation. The results indicate a tendency for the plant to accumulate the uranium in its different parts, and to trans locate it to its stem and leaves. The plant is resistant to high concentrations of uranium, not showing any specific changes in relation to non contaminated areas that might indicate the presence of the contaminant. Therefore, its use as a bio monitor species is limited. (Author)

Baccharis Salicifolia development in the presence of high concentrations of uranium in the arid environment of San Marcos, Chihuahua

International Nuclear Information System (INIS)

Luna P, M. Y.; Alarcon H, M. T.; Silva S, M.; Renteria V, M; Rodriguez V, M. A.; Herrera P, E.; Reyes C, M.; Montero C, M. E.