WorldWideScience

Sample records for americium

  1. Preparation of americium amalgam

    International Nuclear Information System (INIS)

    The authors describe a method for the electrochemical preparation of an americium amalgam from americium dioxide and americium 241 and 243 for use in determining the physicochemical properties of the alloy. Moessbauer spectra were made using neptunium dioxide, in the neptunium 237 form, as an absorber. Results show that electrolysis produces a homogeneous amalgam that gives an unoxidized product on vacuum distillation at 200 degrees C

  2. Americium recovery from reduction residues

    Science.gov (United States)

    Conner, W.V.; Proctor, S.G.

    1973-12-25

    A process for separation and recovery of americium values from container or bomb'' reduction residues comprising dissolving the residues in a suitable acid, adjusting the hydrogen ion concentration to a desired level by adding a base, precipitating the americium as americium oxalate by adding oxalic acid, digesting the solution, separating the precipitate, and thereafter calcining the americium oxalate precipitate to form americium oxide. (Official Gazette)

  3. Preparation of americium amalgam

    International Nuclear Information System (INIS)

    Using the method of NGR-spectroscopy with the aid of 241Am isotope chemical state of transuranium elements in the volume and on the surface of amalgams is studied. Amalgam preparation was realized in a simplified electrolytic cell. It is shown that in the process of amalgam preparation the first order of reaction as to actinide is observed; americium is distributed gradually over the volume and it is partially sorbed by the surface of glass capillary. NGR spectrum of dry residue after mercury distillation at 200 deg C points to the presence of americium-mercury intermetal compounds

  4. Chemistry of americium

    Energy Technology Data Exchange (ETDEWEB)

    Schulz, W.W.

    1976-01-01

    Essential features of the descriptive chemistry of americium are reviewed. Chapter titles are: discovery, atomic and nuclear properties, collateral reading, production and uses, chemistry in aqueous solution, metal, alloys, and compounds, and, recovery, separation, purification. Author and subject indexes are included. (JCB)

  5. Americium-241 - ED 4308

    International Nuclear Information System (INIS)

    This sheet presents the characteristics of Americium-241, its origin, and its radio-physical and biological properties. It briefly describes its use in nuclear medicine. It indicates its dosimetric parameters for external exposure, cutaneous contamination, and internal exposure due to acute contamination or to chronic contamination. It indicates and comments the various exposure control techniques: ambient dose rate measurement, surface contamination measurement, atmosphere contamination. It addresses the means of protection: premise design, protection against external exposure and against internal exposure. It describes how areas are delimited and controlled within the premises: regulatory areas, controls to be performed. It addresses the personnel classification, training and medical survey. It addresses the issue of wastes and effluents. It briefly recalls the administrative procedures related to the authorization and declaration of possession and use of sealed and unsealed sources. It indicates regulatory aspects related to the road transport of Americium-241, describes what is to be done in case of incident or accident (for the different types of contamination or exposure)

  6. The Biokinetic Model of Americium

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    To improve in vivo measurements for detecting internal exposure from transuranium radio nuclides, such as neptunium, plutonium, americium, the bioknetic model was studied. According to ICRP report (1993, 1995, 1997) and other research, the

  7. Americium product solidification and disposal

    International Nuclear Information System (INIS)

    The americium product from the TRUEX processing plant needs to be converted into a form suitable for ultimate disposal. An evaluation of the disposal based on safety, number of process steps, demonstrated operability of the processes, production of low-level alpha waste streams, and simplicity of maintenance with low radiation exposures to personnel during maintenance, has been made. The best process is to load the americium on a cation exchange resin followed by calcination or oxidation of the resin after loading

  8. Science and Technology for Americium Transmutation

    International Nuclear Information System (INIS)

    Americium could be seen as the most troublesome element that is present in nuclear fuel. This thesis offers different points of view on the possibility of americium transmutation. The first point of view elaborates simulations of americium-bearing facilities, namely nuclear data, a popular computational code and modeling techniques. The second point of view is focused on practical usage of the simulations to examine upper limit of americium in a specific reactor

  9. Transmutation of Americium in Fast Neutron Facilities

    OpenAIRE

    Zhang, Youpeng

    2011-01-01

    In this thesis, the feasibility to use a medium sized sodium cooled fast reactor fully loaded with MOX fuel for efficient transmutation of americium is investigated by simulating the safety performance of a BN600-type fast reactor loaded with different fractions of americium in the fuel, using the safety parameters obtained with the SERPENT Monte Carlo code. The focus is on americium mainly due to its long-term contribution to the radiotoxicity of spent nuclear fuel and its deterioration on c...

  10. Production of americium isotopes in France

    International Nuclear Information System (INIS)

    The program of productions of americium 241 and 243 isotopes is based respectively on the retreatment of aged plutonium alloys or plutonium dioxide and on the treatment of plutonium targets irradiated either in CELESTIN reactors for Pu-Al alloys or OSIRIS reactor for plutonium 242 dioxide. All the operations, including americium final purifications, are carried out in hot cells equipped with remote manipulators. The chemical processes are based on the use of extraction chromatography with hydrophobic SiO2 impregnated with extracting agents. Plutonium targets and aged plutonium alloys are dissolved in nitric acid using conventional techniques while plutonium dioxide dissolutions are performed routine at 300 grams scale with electrogenerated silver II in 4M HNO3 at room temperature. The separation between plutonium and americium is performed by extraction of Pu(IV) either on TBP/SiO2 or TOAHNO3/SiO2 column. Americium recovery from waste streams rid of plutonium is realized by chromatographic extraction of Am(III) using mainly TBP and episodically DHDECMP as extractant. The final purification of both americium isotopes uses the selective extraction of Am(VI) on HDDiBMP/SiO2 column at 60 grams scale. Using the overall process a total amount of 1000 grams of americium 241 and 100 grams of americium 243 has been produced nowadays and the AmO2 final product indicates a purity better than 98.5%

  11. Study of americium sorption by humic acids

    International Nuclear Information System (INIS)

    The results of investigation of influence of the cation content and acidity of soil solution on americium sorption by the humic acids have been shown. The most influence on the interphase distribution coefficient in the system 'humic acid - model soil solution' is caused by the presence of the iron (III), calcium ions and acidity of the solution. The increase of the sodium ions concentration in the solution makes an insignificant impact on the americium sorption. (Authors)

  12. Spectrochemical analysis of curium and americium samples

    International Nuclear Information System (INIS)

    Spectrochemical procedures have been developed to determine impurities in americium and curium samples. The simultaneous separation of many impurity elements from the base material (americium and curium) is carried out with extraction and extraction-chromatographic methods using di-2-ethylhexylphosphoric acid. It is shown that part of the elements are separated with extraction or sorption of americium and curium; the other part with the Talspeak process. Two fractions in the extraction chromatography and three fractions in the extraction separation of americium and curium, containing impurities, are analyzed separately by a.c. or d.c. arc spectrography. To increase the sensitivity of the spectrographic analysis and accelerate the burn-up of impurities from the crater of the carbon electrode bismuth fluoride and sodium chloride were used as chemically active substances. The extraction of impurities from weighed quantities of americium and curium samples of 5 to 10 mg permits the lower limit of determined impurity concentrations to be extended to 1 x 10-4 to 5 x 10-3% m/m. (author)

  13. Aqueous Chloride Operations Overview: Plutonium and Americium Purification/Recovery

    Energy Technology Data Exchange (ETDEWEB)

    Kimball, David Bryan [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Skidmore, Bradley Evan [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-06-22

    Acqueous Chloride mission is to recover plutonium and americium from pyrochemical residues (undesirable form for utilization and storage) and generate plutonium oxide and americium oxide. Plutonium oxide is recycled into Pu metal production flowsheet. It is suitable for storage. Americium oxide is a valuable product, sold through the DOE-OS isotope sales program.

  14. Pyrochemical technology of plutonium and americium preparation and purification

    International Nuclear Information System (INIS)

    Pyrochemical tecnology of metallic plutonium and americium preparation and purification is considered. Investigations into plutonium dioxide reduction up to metal; plutonium electrolytic refining in molten salts; plutonium extraction from the molten salts and preparation of americium dioxide and metallic americium from its tetrafluoride are described

  15. Formation of americium and europium humate complexes

    International Nuclear Information System (INIS)

    Binding constants of americium and europium with a humic acid were determined to study if complex formation of trivalent actinide-humates affects dissolved species of the actinides in hydrosphere. The purified humic acid was characterized by means of UV-vis, IR, and pH titration, indicating high carboxylate capacity and low aromaticity. Binding constants of americium and europium humates were determined at pH 4.6 and 6.0 by solvent extraction using 241Am or 152Eu as a tracer. The binding constants for americium-humate obtained preliminarily suggest that complexes with humic acid are not negligible in speciation of trivalent actinides in hydrosphere. The obtained binding constants were nearly identical with those determined previously by the same procedures, but with humic acids of different origin and compositions. (author)

  16. Preparation of americium source for smoke detector

    International Nuclear Information System (INIS)

    This report describes the method developed for the preparation of 241Am source for smoke detector. Americium was electrodeposited from iso-propyl alcohol medium on silver backing. Thin layer of gold (few hundred micro gram thick) was plated on the americium source to make it safe for handling. The thickness of plated gold was such that the alpha radiations from the 241Am source could escape out of the gold layer and cause ionisation in the surrounding air. The performance of the prepared sources were checked in a smoke detector and was found to be satisfactory and comparable to the imported sources. (author). 1 refs., 2 figs., 1 tab

  17. Recovery of americium-241 from raffinates of plutonium purification columns

    International Nuclear Information System (INIS)

    Recovery and purification of americium from ion exchange raffinates generated during purification of aged plutonium is described. The method consists of the following stages: (i) co-precipitation of americium with kilogramme quantities of rare earth oxalates, (ii) destruction of oxalate and removal of residual plutonium from nitric acid medium using anion exchange process, (iii) preliminary separation of americium making use of its preferential uptake on an anion exchange column from thiocyanate medium and (iv) extraction of americium and remaining rare earths into di-(2-ethyl hexyl) phosphoric acid followed by preferential back washing of americium by lactic acid medium containing DTPA. (author)

  18. 1976 Hanford americium exposure incident: psychological aspects

    International Nuclear Information System (INIS)

    Accidents involving exposure to radiation or radioactive materials may involve an unusual degree of emotional trauma. Methods that may be employed in dealing with such trauma are discussed in relation to a specific accident in which a radiation worker was injured and seriously contaminated with americium-241

  19. Americium separations from high salt solutions

    International Nuclear Information System (INIS)

    Americium (III) exhibits an unexpectedly high affinity for anion-exchange material from the high-salt evaporator bottoms solutions--an effect which has not been duplicated using simple salt solutions. Similar behavior is observed for its lanthanide homologue, Nd(III), in complex evaporator bottoms surrogate solutions. There appears to be no single controlling factor--acid concentration, total nitrate concentration or solution ionic strength--which accounts for the approximately 2-fold increase in retention of the trivalent ions from complex solutions relative to simple solutions. Calculation of species activities (i.e., water, proton and nitrate) in such concentrated mixed salt solutions is difficult and of questionable accuracy, but it is likely that the answer to forcing formation of anionic nitrate complexes of americium lies in the relative activities of water and nitrate. From a practical viewpoint, the modest americium removal needs (ca. 50--75%) from nitric acid evaporator bottoms allow sufficient latitude for the use of non-optimized conditions such as running existing columns filled with older, well-used Reillex HPQ. Newer materials, such as HPQ-100 and the experimental bifunctional resins, which exhibit higher distribution coefficients, would allow for either increased Am removal or the use of smaller columns. It is also of interest that one of the experimental neutral-donor solid-support extractants, DHDECMP, exhibits a similarly high level of americium (total alpha) removal from EV bottoms and is much less sensitive to total acid content than commercially-available material

  20. Decontaminaion of metals containing plutonium and americium

    International Nuclear Information System (INIS)

    Melt-slagging (melt-refining) techniques were evaluated as a decontamination and consolidation step for metals contaminated with oxides of plutonium and americium. Experiments were performed in which mild steel, stainless steel, and nickel contaminated with oxides of plutonium and americium were melted in the presence of silicate slags of various compositions. The metal products were low in contamination, with the plutonium and americium strongly fractionated to the slags. Partition coefficients (plutonium in slag/plutonium in steel) of 7 x 106 were measured with boro-silicate slag and of 3 x 106 with calcium, magnesium silicate slag. Decontamination of metals containing as much as 14,000 ppM plutonium appears to be as efficient as for metals with plutonium levels of 400 ppM. Staged extraction, that is, a remelting of processed metal with clean slag, results in further decontamination of the metal. The second extraction is effective with either resistance-furnace melting or electric-arc melting. Slag adhering to the metal ingots and in defects within the ingots is in the important contributors to plutonium retained in processed metals. If these sources of plutonium are controlled, the melt-refining process can be used on a large scale to convert highly contaminated metals to homogeneous and compact forms with very low concentrations of plutonium and americium. A conceptual design of a melt-refining process to decontaminate plutonium- and americium-contaminated metals is described. The process includes single-stage refining of contaminated metals to produce a metal product which would have less than 10 nCi/g of TRU-element contamination. Two plant sizes were considered. The smaller conceptual plant processes 77 kg of metal per 8-h period and may be portable.The larger one processes 140 kg of metal per 8-h period, is stationary, and may be near te maximum size that is practical for a metal decontamination process

  1. Status of Americium-241 recovery at Rocky Flats Plant

    International Nuclear Information System (INIS)

    This paper is presented in two parts: Part I, Molten Salt Extraction of Americium from Molten Plutonium Metal, and Part II, Aqueous Recovery of Americium from Extraction Salts. The Rocky Flats recovery process used for waste salts includes (1) dilute hydrochloric acid dissolution of residues; (2) cation exchange to convert from the chloride to the nitrate system and to remove gross amounts of monovalent impurities; (3) anion exchange separation of plutonium; (4) oxalate precipitation of americium; and (5) calcination of the oxalate at 6000C to yield americium oxide. The aqueous process portion describes attempts to improve the recovery of americium. The first part deals with modifications to the cation exchange step; the second describes development of a solvent extractions process that will recovery americium from residues containing aluminium as well as other common impurities. Results of laboratory work are described. 3 figures, 6 tables. (DP)

  2. Plutonium and americium in soil organic matter

    International Nuclear Information System (INIS)

    A gley soil from west Cumbria, with specific activities in its surface horizon of 5-10 kBq kg-1239,240Pu and comparable 241Am levels, has been used as a source of actinide-enriched organic fractions. Humic and fulvic acids were isolated by conventional alkali extraction and investigated by gel filtration, treatment with organic solvents and differential flocculation procedures. All these techniques are capable of resolving the organics into two or more fractions, with specific activities up to 80 kBq kg-239,240Pu. There is evidence for differentiation of plutonium and americium, with americium being concentrated, to some extent, in the lower molecular weight fractions from gel filtration. (author)

  3. Incentives for transmutation of americium in thermal reactors

    International Nuclear Information System (INIS)

    This report describes possible benefits when americium is irradiated in a thermal reactor. If all plutonium is partitioned from spent fuel, americium is the main contributor to the radiotoxicity of spent fuel upto several thousands of years of storage. It is shown that americium can be transmuted to other nuclides upon irradiation in a thermal reactor, leading to a 50% reduction of the radiotoxicity of neptunium, which can be an important contributor to the dose due to leakage of nuclides after one million years of storage. The radiotoxicity of americium can be reduced considerably after irradiation for 3 to 6 years in a thermal reactor with thermal neutron flux of 1014 cm-2s-1. The strongly α and neutron emitting transmutation products can most probably not be recycled again, so a transmutation process is suggested in which americium is irradiated for 3 to 6 years and then put to final storage. It is shown that the radiotoxicity of the transmuation products after a storage time of about one hundred years can be considerably reduced compared to the radiotoxicity of the initial americium. The same holds for the α activity and heat emission of the transmutation products. Because plutonium in spent fuel contributes for about 80% to the radiotoxicity upto 105 years of storage, recycling and transmutation of plutonium has first priority. Transmutation of americium is only meaningful when the radiotoxicity of plutonium is reduced far below the radiotoxicity of americium. (orig.)

  4. Americium transfer studies using hollow fiber/extractant membranes

    International Nuclear Information System (INIS)

    Americium can be removed from low acid/high nitrate feeds using hollow fiber membrane modules. Americium can be concentrated in the stripping solution. (Maximum observed concentration was a factor of 3.1). Accurel hollow fibers are less prone to leakage problems

  5. Electronic structure of compressed americium metal

    Czech Academy of Sciences Publication Activity Database

    Kolorenč, Jindřich; Shick, Alexander; Caciuffo, R.

    Cambridge: Cambridge University Press,, 2012 - (Anderson, D.; Boot, C.; Burns, P.), s. 177-182. (Materials Research Society Symposium Proceedings. 1444). ISBN 978-1-60511-421-7. ISSN 0272-9172. [2012 MRS Spring Meeting. Sacramento (CA), 09.04.2012-13.04.2012] R&D Projects: GA ČR(CZ) GAP204/10/0330; GA AV ČR IAA100100912 Institutional research plan: CEZ:AV0Z10100520 Keywords : americium * X-ray spectroscopy * LDA+DMFT Subject RIV: BM - Solid Matter Physics ; Magnetism http://journals.cambridge.org/article_S1946427412009463

  6. Electrochemical oxidation of americium in nitric medium: study of reaction mechanisms; Oxydation de l'americium par voie electrochimique: etude des mecanismes

    Energy Technology Data Exchange (ETDEWEB)

    Picart, S.; Chartier, D.; Donnet, L.; Adnet, J.M. [CEA Valrho, (DCC/DRRV/SPHA), 30 - Marcoule (France)

    2000-07-01

    One alternative selected by the CEA for partitioning minor actinides from aqueous solutions containing fission products is the selective extraction of oxidized americium. This is the SESAME process (Selective Extraction and Separation of Americium by Means of Electrolysis) aimed to convert americium to oxidation state (VI) and then extract it with a specific extractant of high valences. This paper presents the study of the electrochemical oxidation of americium in nitric medium which represents an important stage of the process. The reaction can be divided into two main steps: oxidation of americium (III) to americium (IV), and then of americium (IV) to americium (VI). For the first oxidation step, a ligand L is needed to stabilize the intermediate species americium (IV) which disproportionates in its free form into americium (III) and (V). Phospho-tungstate or silico-tungstate are appropriate ligands because they are stable in concentrated nitric acid and show a great affinity for metallic cations at oxidation state (IV) (Table 1 lists the stability constants of americium (IV) complexes). The presence of the lacunary poly-anion lowers the potential of the americium (IV) / americium (Ill) redox pair (see Figure 5 for the diagram of the apparent formal potential of americium versus ligand concentration). This makes it thermodynamically possible to oxidize americium (III) into americium (IV) at the anode of an electrolyzer in nitric acid. For the second oxidation step, a strong oxidant redox mediator, like silver (II), is needed to convert complexed americium at oxidation state (IV) to oxidation state (V). The AmVL complex is then hydrolyzed to yield americyle (V) aqua ion. A spectroscopic Raman study with {sup 18}O labeled species showed that the oxygen atoms of the americyle moiety came from water. This indicates that water hydrolyzes the americium (V) complex to produce americyle (V) aqua ion, AmO{sub 2}{sup +}. This cation reacts with silver (Il) to give

  7. Modelling of americium stripping in the EXAm process

    International Nuclear Information System (INIS)

    The EXAm process aims at recovering americium alone contained in the PUREX raffinate. The americium stripping model has been revised to take into account a change of stripping aqueous phase and up-to-date experimental results conducted within DRCP to improve knowledge about complexes. This work represents a first approximation at modelling americium stripping. The modelling work has led to synthesize the knowledge on chemical phenomenology and adopt assumptions that best reflect experimental results. The modelling has been implemented in PAREX code in order to simulate this step to prepare and understand tests to be carried out in mixer settlers. (authors)

  8. Higher Americium Oxidation State Research Roadmap

    Energy Technology Data Exchange (ETDEWEB)

    Mincher, Bruce J. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Law, Jack D. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Goff, George S. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Moyer, Bruce A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Burns, Jon D. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Lumetta, Gregg J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Sinkov, Sergey I. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Shehee, Thomas C. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Hobbs, David T. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2015-12-18

    The partitioning of hexavalent Am from dissolved nuclear fuel requires the ability to efficiently oxidize Am(III) to Am(VI) and to maintain that oxidation state for a length of time sufficient to perform the separation. Several oxidants have been, or are being developed. Chemical oxidants include Ag-catalyzed ozone, Ag-catalyzed peroxydisulfate, Cu(III) periodate, and sodium bismuthate. Hexavalent americium has also now successfully been prepared by electrolysis, using functionalized electrodes. So-called auto-reduction rates of Am(VI) are sufficiently slow to allow for separations. However, for separations based on solvent extraction or ion exchange using organic resins, the high valence state must be maintained under the reducing conditions of the organic phase contact, and a holding oxidant is probably necessary. Until now, only Cu(III) periodate and sodium bismuthate oxidation have been successfully combined with solvent extraction separations. Bismuthate oxidation provided the higher DAm, since it acts as its own holding oxidant, and a successful hot test using centrifugal contactors was performed. For the other oxidants, Ag-catalyzed peroxydisulfate will not oxidize americium in nitric acid concentrations above 0.3 M, and it is not being further investigated. Peroxydisulfate in the absence of Ag catalysis is being used to prepare Am(V) in ion exchange work, discussed below. Preliminary work with Ag-catalyzed ozone has been unsuccessful for extractions of Am(VI) from 6.5 M HNO3, and only one attempt at extraction, also from 6.5 M HNO3, using the electrolytic oxidation has been attempted. However, this high acid concentration was based on the highest Am extraction efficiency using the bismuthate oxidant; which is only sparingly soluble, and thus the oxidation yield is based on bismuthate solubility. Lower acid concentrations may be sufficient with alternative oxidants and work with Ag-ozone, Cu(III) and electrolysis is on-going. Two non

  9. Mixed chelation therapy for removal of plutonium and americium

    International Nuclear Information System (INIS)

    Iron-binding compounds, 2,3-dihydroxybenzoic acid (DHBA), 2-hydroxybenzoic acid (HBA), and 2-(acetyloxy)benzoic acid (ABA), were tested for their ability to remove americium and plutonium from rats following intraperitioneal injection of the radionuclides as citrates (pH 5). Treatments, 2 mmol/kg, were given on days 3, 6, 10, 12 and 14 following the actinide injection. DHBA and HBA caused about a 20% decrease in liver retention of americium compared to the control value, and DHB caused a similar effect for plutonium. The above agents, co-administered with 0.5 mmol polyaminopolycarboxylic acid (PAPCA)-type chelons, did not change tissue retention of americium and plutonium from that due to the PAPCAs alone. Administration of americium and plutonium to the same rats is useful for studying removal agents since the two actinides behave independently in their biological disposition and response to removal

  10. Plutonium and Americium Geochemistry at Hanford: A Site Wide Review

    Energy Technology Data Exchange (ETDEWEB)

    Cantrell, Kirk J.; Felmy, Andrew R.

    2012-08-23

    This report was produced to provide a systematic review of the state-of-knowledge of plutonium and americium geochemistry at the Hanford Site. The report integrates existing knowledge of the subsurface migration behavior of plutonium and americium at the Hanford Site with available information in the scientific literature regarding the geochemistry of plutonium and americium in systems that are environmentally relevant to the Hanford Site. As a part of the report, key research needs are identified and prioritized, with the ultimate goal of developing a science-based capability to quantitatively assess risk at sites contaminated with plutonium and americium at the Hanford Site and the impact of remediation technologies and closure strategies.

  11. Americium/Curium Disposition Life Cycle Planning Study

    International Nuclear Information System (INIS)

    At the request of the Department of Energy Savannah River Office (DOE- SR), Westinghouse Savannah River Company (WSRC) evaluated concepts to complete disposition of Americium and Curium (Am/Cm) bearing materials currently located at the Savannah River Site (SRS)

  12. Gamma-sources on the basis of metallic americium-241

    International Nuclear Information System (INIS)

    A batch of gamma-radiation sources has been manufactured from metallic americium-241 of isotopic purity, its activity varying from 0.08 to 0.93 GBq. The cores of the sources are high-purity americium metal condensate on a tantalum or stainless steel substrate prepared by thermal decomposition of 241Pu-241Am alloy in a high vacuum. 7 refs., 1 tab

  13. Pyrochemical investigations into recovering plutonium from americium extraction salt residues

    International Nuclear Information System (INIS)

    Progress into developing a pyrochemical technique for separating and recovering plutonium from spent americium extraction waste salts has concentrated on selective chemical reduction with lanthanum metal and calcium metal and on the solvent extraction of americium with calcium metal. Both techniques are effective for recovering plutonium from the waste salt, although neither appears suitable as a separation technique for recycling a plutonium stream back to mainline purification processes. 17 refs., 13 figs., 2 tabs

  14. 1976 Hanford americium-exposure incident: external decontamination procedures

    International Nuclear Information System (INIS)

    An accident resulted in the deposition on an injured workman's skin surfaces, in acid-burned areas and in lacerations, of something in excess of 6 mCi americium-241. The external decontamination procedures used, the change in americium content of the skin during the course of treatment, and some of the unusual problems encountered from the extrusion of foreign material and flaking of skin and scar tissue are described

  15. Electrochemical oxidation of americium in nitric medium: study of reaction mechanisms

    International Nuclear Information System (INIS)

    One alternative selected by the CEA for partitioning minor actinides from aqueous solutions containing fission products is the selective extraction of oxidized americium. This is the SESAME process (Selective Extraction and Separation of Americium by Means of Electrolysis) aimed to convert americium to oxidation state (VI) and then extract it with a specific extractant of high valences. This paper presents the study of the electrochemical oxidation of americium in nitric medium which represents an important stage of the process. The reaction can be divided into two main steps: oxidation of americium (III) to americium (IV), and then of americium (IV) to americium (VI). For the first oxidation step, a ligand L is needed to stabilize the intermediate species americium (IV) which disproportionates in its free form into americium (III) and (V). Phospho-tungstate or silico-tungstate are appropriate ligands because they are stable in concentrated nitric acid and show a great affinity for metallic cations at oxidation state (IV) (Table 1 lists the stability constants of americium (IV) complexes). The presence of the lacunary poly-anion lowers the potential of the americium (IV) / americium (Ill) redox pair (see Figure 5 for the diagram of the apparent formal potential of americium versus ligand concentration). This makes it thermodynamically possible to oxidize americium (III) into americium (IV) at the anode of an electrolyzer in nitric acid. For the second oxidation step, a strong oxidant redox mediator, like silver (II), is needed to convert complexed americium at oxidation state (IV) to oxidation state (V). The AmVL complex is then hydrolyzed to yield americyle (V) aqua ion. A spectroscopic Raman study with 18O labeled species showed that the oxygen atoms of the americyle moiety came from water. This indicates that water hydrolyzes the americium (V) complex to produce americyle (V) aqua ion, AmO2+. This cation reacts with silver (Il) to give americyle (VI) ion. Figure

  16. Complexation of americium with humic acid

    International Nuclear Information System (INIS)

    As a part of the interlaboratory comparison exercise for the complexation of humic acid and colloid generation (COCO-Club activities) in the CEC project MIRAGE-II, the complexation of americium with humic acid has been studied in our laboratory. Two humic acids were used for the study: Aldrich-HA(H+) which is a reference humic acid of the COCO-Club and Bradford-HA(H+) from Lake Bradford, Florida. A wide concentration range of humic acid and different ratios of Am to humic acid have been investigated between pH 5 and 6 with the ionic strength of 0.1 M and 1.0 M. The complexation has been studied by UV-spectroscopy, Laser-induced Photoacoustic Spectroscopy (LPAS) and ultrafiltration. LPAS is used for the submicromolar concentration range where the sensitivity of UV spectroscopy is not accessible. Ultrafiltration is used for low Am to humic acid ratios where both spectroscopic methods are not applicable. Varying the humic acid concentration over three orders of magnitude, only a 1:1 type of binding is observed. No significant variation of the stability constant is found in the investigated range of pH and ionic strength. However, the precipitation tendency and the loading capacity of humic acid are found to depend sensitively on pH and ionic strength. The complexation study provides a deep insight into the influence of humic acid on the migration behaviour of fission products and actinides in the geosphere. (orig.)

  17. Analysis of BWR lattices to recycle americium

    International Nuclear Information System (INIS)

    This study was carried out to assess the ability to eliminate meaningful quantities of americium in a primarily thermal neutron flux by 'spiking' modern BWR fuel with this minor actinide (MA). The studies carried out so far include the simulation of modern 10 x 10 BWR lattices employing the Westinghouse lattice physics code PHOENIX-4 alongside validation studies using MCNP5 models of the same lattices that were spatially depleted via the MONTEBURNS code coupling to ORIGEN. When considering the total inventory of minor actinides in Am-spiked pins, excluding isotopes of uranium and plutonium, the results indicate that a reduction of approximately 50% or more in the total mass inventory of these minor actinides is viable within the selected pins. Therefore, these preliminary results have encouraged the extension of this work to the development of improved lattice designs to help optimize the transmutation rates as well as absolute MA inventory reductions. The ultimate goal being to design batches of these advanced BWR bundles alongside multi-cycle core reload strategies. (authors)

  18. Applicability of insoluble tannin to treatment of waste containing americium

    International Nuclear Information System (INIS)

    The applicability of insoluble tannin adsorbent to the treatment of aqueous waste contaminated with americium has been investigated. Insoluble tannin is considered highly applicable because it consists of only carbon, hydrogen and oxygen and so its volume can be easily reduced by incineration. This report describes measurements of the americium distribution coefficient in low concentration nitric acid. The americium distribution coefficients were found to decrease with increasing concentration of nitric acid and sodium nitrate, and with increasing temperature. At 25 C in 2.0 x 10-3 M HNO3, the distribution coefficient was found to be 2000 ml g-1. The adsorption capacity was determined by column experiments using europium as a simulant of americium, and found to be 7 x 10-3 mmol g-1-dried tannin in 0.01 M HNO3 at 25 C, which corresponds to approximately 1.7 mg-241Am/g-adsorbent(dried). The prospect of applying the adsorbent to the treatment of aqueous waste contaminated with americium appears promising. (orig.)

  19. A TRUEX-based separation of americium from the lanthanides

    Energy Technology Data Exchange (ETDEWEB)

    Bruce J. Mincher; Nicholas C. Schmitt; Mary E. Case

    2011-03-01

    Abstract: The inextractability of the actinide AnO2+ ions in the TRUEX process suggests the possibility of a separation of americium from the lanthanides using oxidation to Am(V). The only current method for the direct oxidation of americium to Am(V) in strongly acidic media is with sodium bismuthate. We prepared Am(V) over a wide range of nitric acid concentrations and investigated its solvent extraction behavior for comparison to europium. While a separation is achievable in principal, the presence of macro amounts of cerium competes for the sparingly soluble oxidant and the oxidant itself competes for CMPO complexation. These factors conspire to reduce the Eu/Am separation factor from ~40 using tracer solutions to ~5 for extractions from first cycle raffinate simulant solution. To separate pentavalent americium directly from the lanthanides using the TRUEX process, an alternative oxidizing agent will be necessary.

  20. Salvage of plutonium-and americium-contaminated metals

    International Nuclear Information System (INIS)

    Melt-slagging techniques were evaluated as a decontamination and consolidation step for metals contaminated with oxides of plutonium and americium. Experiments were performed in which mild steel, stainless steel, and nickel metals contaminated with oxides of plutonium and americium were melted in the presence of silicate slags of various compositions. The metal products were low in contamination, with the plutonium and americium strongly fractionated to the slags. Partition coefficients (plutonium in slag/plutonium in steel) of 7*10/sup 6/ with borosilicate slag and 3*10/sup 6/ for calcium, magnesium silicate slag were measured. Decontamination of metals containing as much as 14,000 p.p.m. plutonium appears to be as efficient as that of metals with plutonium levels of 400 p.p.m. Staged extraction, that is, a remelting of processed metal with clean slag, results in further decontamination of the metal. 10 refs

  1. Uptake of americium-241 by algae and bacteria

    International Nuclear Information System (INIS)

    The uptake of americium by three algae, scenedesmus obliquus, selenastrum capricomutum and chlorella pyrenosdosa and a bacterium aeromonas hydrophila was studied. Live and fixed cells of each algal species and live bacterial cells were used. it is shown that algae and bacteria concentrate americium 241 to a high degree which makes them important links in the biomagnification phenomenon which may ultimately lead to a human hazard and be potentially important in recycling Am 241 in the water column and mobilization from sediments. Chemical fixation of algal cells caused increased uptake which indicated that uptake is by passive diffusion and probably due to chemical alteration of surface binding sites. (U.K.)

  2. Americium incineration by recycling in target rods using coated particles

    International Nuclear Information System (INIS)

    This paper proposes a type of target rod based on the use of coated particles, for an efficient incineration of americium in nuclear reactors. The analysis takes advantage of the experience gained in the past from long duration irradiation without damage of coated particles with plutonium oxide kernels. A conservative theoretical evaluation of the gas pressure inside the coated particles at the end of irradiation allows comparing the well known conditions of the plutonium oxide particles which were successfully irradiated to high burn-up, with a preliminary design of americium oxide particles. (authors)

  3. 1976 Hanford americium exposure incident: overview and perspective

    International Nuclear Information System (INIS)

    Salient features of the 1976 Hanford americium exposure incident are discussed. Comparisons are made with previous human and animal exposure data, and conclusions drawn relative to the injured workman, to health physics practices, and to the adequacy of current exposure limits

  4. Americium retention by the smectite hectorite

    International Nuclear Information System (INIS)

    Document available in extended abstract form only. Clay minerals may play an important role in a high level nuclear waste disposal site. Smectites may be major components of backfill material used to enhance the retention properties of engineered barriers. Furthermore, they have also been detected in the alteration layer of nuclear waste glass corroded in laboratory experiments. For example, the smectite hectorite (Na0.33[Mg2.67Li0.33Si4O10(OH)2]) was identified as phase forming upon waste matrix dissolution and subsequent reprecipitation. Smectites are known to be highly reactive with respect to cations in aqueous systems. Several distinct molecular scale binding mechanisms may operate, but the most effective retention may occur by incorporation in the bulk structure, especially if a (meta)stable solid solution forms. Investigations showed the possibility to incorporate Lu(III) in a clay-like octahedral site in hectorite by coprecipitation. Furthermore, luminescence studies on hectorite synthesized in the presence of Cm(III) or Eu(III) were consistent with an incorporation in the bulk structure. However, structural data such as coordination numbers and bond lengths are still missing for the actinides. In the present study, Am(III) was coprecipitated with and adsorbed on hectorite to decipher the actual retention mechanism(s). Hectorite was synthesized in the presence of Am(III) (sample AmCopHec) from an Am-containing brucite precursor phase. Briefly, brucite was freshly precipitated in the presence of Am(III) (Am:Mg molar ratio of 1:1175) and washed. The resulting sol was aged in a tightly closed vessel in the presence of LiF and silica sol for several days at 90 C. Separately, an Am-containing brucite phase (sample AmCopBru) was prepared under identical conditions as described above, and the americium aqua ions were adsorbed on hectorite (m/V = 2 g/L, [Am(III)]tot = 105 μmol/L, 0.5 mol/L NaClO4, pH = 6.4(1), sample AmSorbHec) and used as reference samples. X

  5. Synthesis and characterization of uranium-americium mixed oxides

    International Nuclear Information System (INIS)

    Americium isotopes represent a significant part of high-level and long-lived nuclear waste in spent fuels. Among the envisaged reprocessing scenarios, their transmutation in fast neutron reactors using uranium-americium mixed-oxide pellets (U1-xAmxO2±δ) is a promising option which would help decrease the ecological footprint of ultimate waste repository sites. In this context, this thesis is dedicated to the study of such compounds over a wide range of americium contents (7.5 at.% ≤ Am/(U+Am) ≤ 70 at.%), with an emphasis on their fabrication from single-oxide precursors and the assessment of their structural and thermodynamic stabilities, also taking self-irradiation effects into account. Results highlight the main influence of americium reduction to Am(+III), not only on the mechanisms of solid-state formation of the U1-xAmxO2±δ solid solution, but also on the stabilization of oxidized uranium cations and the formation of defects in the oxygen sublattice such as vacancies and cub-octahedral clusters. In addition, the data acquired concerning the stability of U1-xAmxO2±δ compounds (existence of a miscibility gap, vaporization behavior) were compared to calculations based on new thermodynamic modelling of the U-Am-O ternary system. Finally, α-self-irradiation-induced structural effects on U1-xAmxO2±δ compounds were analyzed using XRD, XAS and TEM, allowing the influence of americium content on the structural swelling to be studied as well as the description of the evolution of radiation-induced structural defects. (author)

  6. Reduction Rates for Higher Americium Oxidation States in Nitric Acid

    Energy Technology Data Exchange (ETDEWEB)

    Grimes, Travis Shane [Idaho National Lab. (INL), Idaho Falls, ID (United States); Mincher, Bruce Jay [Idaho National Lab. (INL), Idaho Falls, ID (United States); Schmitt, Nicholas C [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2015-09-30

    The stability of hexavalent americium was measured using multiple americium concentrations and nitric acid concentrations after contact with the strong oxidant sodium bismuthate. Contrary to our hypotheses Am(VI) was not reduced faster at higher americium concentrations, and the reduction was only zero-order at short time scales. Attempts to model the reduction kinetics using zero order kinetic models showed Am(VI) reduction in nitric acid is more complex than the autoreduction processes reported by others in perchloric acid. The classical zero-order reduction of Am(VI) was found here only for short times on the order of a few hours. We did show that the rate of Am(V) production was less than the rate of Am(VI) reduction, indicating that some Am(VI) undergoes two electron-reduction to Am(IV). We also monitored the Am(VI) reduction in contact with the organic diluent dodecane. A direct comparison of these results with those in the absence of the organic diluent showed the reduction rates for Am(VI) were not statistically different for both systems. Additional americium oxidations conducted in the presence of Ce(IV)/Ce(III) ions showed that Am(VI) is reduced without the typical growth of Am(V) observed in the systems sans Ce ion. This was an interesting result which suggests a potential new reduction/oxidation pathway for Am in the presence of Ce; however, these results were very preliminary, and will require additional experiments to understand the mechanism by which this occurs. Overall, these studies have shown that hexavalent americium is fundamentally stable enough in nitric acid to run a separations process. However, the complicated nature of the reduction pathways based on the system components is far from being rigorously understood.

  7. Liquid-liquid extraction separation and determination of plutonium and americium

    International Nuclear Information System (INIS)

    A procedure is described for the determination of plutonium and americium after their initial separation on barium sulfate. The barium sulfate is dissolved in perchloric acid and the antinides and lanthanides are extracted into bis(2-ethylhexyl)phosphoric acid (HDEHP). Americium along with other tervalent actinides and lanthanides is stripped from HDEHP with nitric acid. The lanthanides are removed on a column of HDEHP supported on Teflon powder, and the americium and other tervalent actinides are electrodeposited for their determination by α spectrometry. The plutonium is stripped with nitric acid after reduction to the tervalent state with 2,5-di-tert-butylhydroquinone and electrodeposited for α spectrometry. Decontamination factors for plutonium and americium from each other and from other α emitters are 104 to 105. Two hours are required for the liquid-liquid extraction separations of plutonium and americium from eight samples. Recoveries of americium and plutonium through the HDEHP separatons are 99% and 95%, respectively

  8. Calculational study on irradiation of americium fuel samples in the Petten High Flux Reactor

    International Nuclear Information System (INIS)

    A calculational study on the irradiation of americium samples in the Petten High Flux Reactor (HFR) has been performed. This has been done in the framework of the international EFTTRA cooperation. For several reasons the americium in the samples is supposed to be diluted with a neutron inert matrix, but the main reason is to limit the power density in the sample. The low americium nuclide density in the sample (10 weight % americium oxide) leads to a low radial dependence of the burnup. Three different calculational methods have been used to calculate the burnup in the americium sample: Two-dimensional calculations with WIMS-6, one-dimensional calculations with WIMS-6, and one-dimensional calculations with SCALE. The results of the different methods agree fairly well. It is concluded that the radiotoxicity of the americium sample can be reduced upon irradiation in our scenario. This is especially the case for the radiotoxicity between 100 and 1000 years after storage. (orig.)

  9. Neptunium and americium control for international non-proliferation regime

    International Nuclear Information System (INIS)

    It was decided in the IAEA Board of Governors Meeting held in Sept. 1999 that Neptunium and Americium could be diverted for manufacturing nuclear weapon or explosives, so that appropriate measures should be taken for the prevention of proliferation of these materials. It is expected to take relatively long time for settling down the aligned system dealing with the above materials because the present regulatory statement was prepared on the basis of voluntary offers from the States concerned. The necessity of preventive measures is being convinced among Member States, but it would not be easy to take voluntary participation in detail because of their respective interests. It is expected that this paper could contribute to the effective response as to the international commitments as well as for protecting the domestic nuclear industry and R and D area through analysis on the IAEA's approach on Neptunium and Americium

  10. Thermophysical properties of americium-containing barium plutonate

    International Nuclear Information System (INIS)

    Polycrystalline specimens of americium-containing barium plutonate have been prepared by mixing the appropriate amounts of (Pu0.91Am0.09)O2 and BaCO3 powders followed by reacting and sintering at 1600 K under the flowing gas atmosphere of dry-air. The sintered specimens had a single phase of orthorhombic perovskite structure and were crack-free. Elastic moduli were determined from longitudinal and shear sound velocities. Debye temperature was also determined from sound velocities and lattice parameter measurements. Thermal conductivity was calculated from measured density at room temperature, literature values of heat capacity and thermal diffusivity measured by laser flash method in vacuum. Thermal conductivity of americium-containing barium plutonate was roughly independent of temperature and registered almost the same magnitude as that of BaPuO3 and BaUO3. (author)

  11. 1976 Hanford americium-exposure incident: decontamination and treatment facility

    International Nuclear Information System (INIS)

    An injured worker, contaminated with over 6 mCi of americium-241, required special treatment and housing for 4 months. This paper is a description of the design and management of the facility in which most of the treatment and housing occurred. The problems associated with contamination control, waste handling, supplies, and radiological concerns during the two-stage transfer of the patient from a controlled situation to his normal living environment are discussed in detail

  12. Recycling heterogeneous americium targets in a boiling water reactor

    International Nuclear Information System (INIS)

    One of the limiting contributors to the heat load constraint for a long term spent fuel repository is the decay of americium-241. A possible option to reduce the heat load produced by Am-241 is to eliminate it via transmutation in a light water reactor thermal neutron environment, in particular, by taking advantage of the large thermal fission cross section of Am-242 and Am-242m. In this study we employ lattice loading optimization techniques to define the loadings and arrangements of fuel pins with blended americium and uranium oxide in boiling water reactor bundles, specifically, by defining the incineration of pre-loaded americium as an objective function to maximize americium transmutation. Subsequently, the viability of these optimized lattices is tested by assembling them into bundles with Am-spiked fuel pins and by loading these bundles into realistic three-dimensional BWR core-wide simulations that model multiple reload cycles and observe standard operational constraints. These simulations are possible via our collaboration with the Westinghouse Electric Co. which facilitates the use of industrial-caliber design tools such as the PHOENIX-4/POLCA-7 sequence and the Core Master 2 GUI work environment for fuel management. The resulting analysis confirms the ability to axially uniformly eliminating roughly 90% of the pre-loaded inventory of recycled Am-241 in BWR bundles with heterogeneous target pins. This high level of incineration was achieved within three to four 18-month operational cycles, which is equivalent to a typical in-core residence time of a BWR bundle.

  13. Ingestion Pathway Transfer Factors for Plutonium and Americium

    Energy Technology Data Exchange (ETDEWEB)

    Blanchard, A.

    1999-07-28

    Overall transfer factors for major ingestion pathways are derived for plutonium and americium. These transfer factors relate the radionuclide concentration in a given foodstuff to deposition on the soil. Equations describing basic relationships consistent with Regulatory Guide 1.109 are followed. Updated values and coefficients from IAEA Technical Reports Series No. 364 are used when a available. Preference is given to using factors specific to the Savannah River Site.

  14. Gut uptake factors for plutonium, americium and curium

    International Nuclear Information System (INIS)

    Data on estimates of the absorption of plutonium, americium and curium from the human gut based on measurements of uptake in other mammalian species are reviewed. It is proposed that for all adult members of the public ingesting low concentrations of plutonium in food and water, 0.05% would be an appropriate value of absorption except when the conditions of exposure are known and a lower value can be justified. For dietary intakes of americium and curium, the available data do not warrant a change from the ICRP value of 0.05%. For newborn children ingesting americium, curium and soluble forms of plutonium, a value of 1% absorption is proposed for the first 3 months of life during which the infant is maintained on a milk diet. It is proposed that a value of 0.5% should be used for the first year of life to take account of the gradual maturation of the gut. In considering the ingestion of insoluble oxides of plutonium by infants, it is proposed that absorption is taken as 0.1% for the first 3 months and 0.05% for the first year. (author)

  15. Airborne plutonium-239 and americium-241 concentrations measured from the 125-meter Hanford Meteorological Tower

    International Nuclear Information System (INIS)

    Airborne plutonium-239 and americium-241 concentrations and fluxes were measured at six heights from 1.9 to 122 m on the Hanford meteorological tower. The data show that plutonium-239 was transported on nonrespirable and small particles at all heights. Airborne americium-241 concentrations on small particles were maximum at the 91 m height

  16. Effect of 241-americium on bone marrow stroma

    International Nuclear Information System (INIS)

    The regulation of haemopoiesis occurs via complex interactions between the stroma and the haemopoietic cells. An attempt to further clarifying the mechanisms and the exact role of the stroma in the regulation was made in a study. Results revealed that the murine bone marrow stromal cells are highly radiosensitive after injection with 241-americium and can thus be considered as a target population after internal contamination. In addition, observations are made which may be important for risk estimation for the developing animal and during pregnancy. Contamination in utero and by lactation shows persistent damage up to 1 year after contamination at an average annual dose of 5 cGy. (author)

  17. Recovery of americium-241 from aged plutonium metal

    International Nuclear Information System (INIS)

    After separation and purification, both actinides were precipitated as oxalates and calcined. A large-scale process was developed using dissolution, separation, purification, precipitation, and calcination. Efforts were made to control corrosion, to avoid product contamination, to keep the volume of process and waste solutions manageable, and to denitrate solutions with formic acid. The Multipurpose Processing Facility (MPPF), designed for recovery of transplutonium isotopes, was used for the first time for the precipitation and calcination of americium. Also, for the first time,, large-scale formic acid denitration was performed in a canyon vessel at SRP

  18. Preferential decorporation of americium by pulmonary administration of DTPA dry powder after inhalation of aged PuO2 containing americium in rats

    International Nuclear Information System (INIS)

    After inhalation of plutonium oxides containing various percentages of americium in rats, we identified an acellular transient pulmonary compartment, the epithelial lining fluid (ELF), in which a fraction of actinide oxides dissolve prior to absorption and subsequent extrapulmonary deposit. Chelation therapy is usually considered to be poorly efficient after inhalation of actinide oxides. However, in the present study, prompt pulmonary administration of diethylenetriaminepentaacetic acid (DTPA) as a dry powder led to a decrease in actinide content in ELF together with a limitation of bone and liver deposits. Because americium is more soluble than plutonium, higher amounts of americium were found in ELF, extrapulmonary tissues and urine. Our results also demonstrated that the higher efficacy of DTPA on americium compared to plutonium in ELF induced a preferential inhibition of extrapulmonary deposit and a greater urinary excretion of americium compared to plutonium. All together, our data justify the use of an early and local DTPA treatment after inhalation of plutonium oxide aerosols in which americium can be in high proportion such as in aged compounds. (authors)

  19. Analytical performance of radiochemical method for americium determination in urine

    International Nuclear Information System (INIS)

    This paper presents an analytical method developed and adapted for separation and analysis of Plutonium (Pu) isotopes and Americium (Am) in urine samples. The proposed method will attend the demand of internal exposure monitoring program for workers involved mainly with dismantling rods and radioactive smoke detectors. In this experimental procedure four steps are involved as preparation of samples, sequential radiochemical separation, preparation of the source for electroplating and quantification by alpha spectrometry. In the first stage of radiochemical separation, plutonium is conventionally isolated employing the anion exchange technique. Americium isolation is achieved sequentially by chromatographic extraction (Tru.spec column) from the load and rinse solutions coming from the anion exchange column. The 243Am tracer is added into the sample as chemical yield monitors and to correct the results improving the precision and accuracy. The mean recovery obtained is 60%, and the detection limit for 24h urine sample is 1.0 mBq L-1 in accordance with the literature. Based in the preliminary results, the method is appropriate to be used in monitoring programme of workers with a potential risk of internal contamination. (author)

  20. Placental transfer of americium and plutonium in mice

    International Nuclear Information System (INIS)

    Actinide element release to the environment and subsequent transfer through food chains to pregnant women may present a radiation hazard to fetuses in utero. To measure americium incorporation, four groups of pregnant mice were intravenously dosed with four concentrations of 243Am citrate in late pregnancy. Concentrations of 243Am in fetuses, placentas, and maternal femur, liver, carcass and pelt were determined 48 hr after injection. Doses were chosen so that the number of atoms of 243Am in each injected dose was equal to the number of atoms of 239Pu used in an earlier study of transplacental movement. Results indicate that, atom for atom, americium is incorporated into fetal tissue in lesser amounts (10-25 times) than is plutonium when intravenously administered to pregnant mice in equal atom amounts. Tissue analyses indicated that, at low dose levels, the average fraction of the dose incorporated into the fetuses decreased as the dose to the pregnant mouse was increased. A similar pattern was noted for placentas and maternal femurs. Data indicate that one must make extrapolations from low dose data only to make reasonable and realistic estimates of the transplacental movement and fetal incorporation of environmental levels of actinide elements in man and other species. (author)

  1. Development of separation techniques of americium from reprocessing solution

    International Nuclear Information System (INIS)

    Americium(Am) and neptunium(Np) finally transfer to the waste stream in the current PUREX reprocessing process. As an option, some methods have been developed to recover Am and Np from the waste stream to decrease long-term toxicity of the high level waste. The most stable valence state of Am is III, but TBP (tri-n-butyl phosphate) which is an extractant used in the PUREX reprocessing does not extract Am(III). Therefore, some special extractants have been developed to recover Am(III). However, they also extract rare-earth elements(REs), which necessitates the separation process for Am from REs. We have been developing a separation process which consists of valence control of Am to the VI state and its extraction with TBP. This process allows Am recovery from reprocessing solution and Am separation from REs simultaneously. Americium(III) is oxidized to Am(VI) by electrochemical oxidation and chemical oxidation using peroxodisulfate ammonium and silver nitrate. The latter was adopted here because the chemical oxidation reaction proceeds faster than the electrochemical method. Reaction mechanisms of oxidation and extraction were investigated. Based on the mechanisms, we found that extraction efficiency could be improved and waste generation could be minimized. (author)

  2. Solubility of Plutonium (IV) Oxalate During Americium/Curium Pretreatment

    Energy Technology Data Exchange (ETDEWEB)

    Rudisill, T.S.

    1999-08-11

    Approximately 15,000 L of solution containing isotopes of americium and curium (Am/Cm) will undergo stabilization by vitrification at the Savannah River Site (SRS). Prior to vitrification, an in-tank pretreatment will be used to remove metal impurities from the solution using an oxalate precipitation process. Material balance calculations for this process, based on solubility data in pure nitric acid, predict approximately 80 percent of the plutonium in the solution will be lost to waste. Due to the uncertainty associated with the plutonium losses during processing, solubility experiments were performed to measure the recovery of plutonium during pretreatment and a subsequent precipitation process to prepare a slurry feed for a batch melter. A good estimate of the plutonium content of the glass is required for planning the shipment of the vitrified Am/Cm product to Oak Ridge National Laboratory (ORNL).The plutonium solubility in the oxalate precipitation supernate during pretreatment was 10 mg/mL at 35 degrees C. In two subsequent washes with a 0.25M oxalic acid/0.5M nitric acid solution, the solubility dropped to less than 5 mg/mL. During the precipitation and washing steps, lanthanide fission products in the solution were mostly insoluble. Uranium, and alkali, alkaline earth, and transition metal impurities were soluble as expected. An elemental material balance for plutonium showed that greater than 94 percent of the plutonium was recovered in the dissolved precipitate. The recovery of the lanthanide elements was generally 94 percent or higher except for the more soluble lanthanum. The recovery of soluble metal impurities from the precipitate slurry ranged from 15 to 22 percent. Theoretically, 16 percent of the soluble oxalates should have been present in the dissolved slurry based on the dilution effects and volumes of supernate and wash solutions removed. A trace level material balance showed greater than 97 percent recovery of americium-241 (from the beta dec

  3. Solubility of Plutonium (IV) Oxalate During Americium/Curium Pretreatment

    International Nuclear Information System (INIS)

    Approximately 15,000 L of solution containing isotopes of americium and curium (Am/Cm) will undergo stabilization by vitrification at the Savannah River Site (SRS). Prior to vitrification, an in-tank pretreatment will be used to remove metal impurities from the solution using an oxalate precipitation process. Material balance calculations for this process, based on solubility data in pure nitric acid, predict approximately 80 percent of the plutonium in the solution will be lost to waste. Due to the uncertainty associated with the plutonium losses during processing, solubility experiments were performed to measure the recovery of plutonium during pretreatment and a subsequent precipitation process to prepare a slurry feed for a batch melter. A good estimate of the plutonium content of the glass is required for planning the shipment of the vitrified Am/Cm product to Oak Ridge National Laboratory (ORNL).The plutonium solubility in the oxalate precipitation supernate during pretreatment was 10 mg/mL at 35 degrees C. In two subsequent washes with a 0.25M oxalic acid/0.5M nitric acid solution, the solubility dropped to less than 5 mg/mL. During the precipitation and washing steps, lanthanide fission products in the solution were mostly insoluble. Uranium, and alkali, alkaline earth, and transition metal impurities were soluble as expected. An elemental material balance for plutonium showed that greater than 94 percent of the plutonium was recovered in the dissolved precipitate. The recovery of the lanthanide elements was generally 94 percent or higher except for the more soluble lanthanum. The recovery of soluble metal impurities from the precipitate slurry ranged from 15 to 22 percent. Theoretically, 16 percent of the soluble oxalates should have been present in the dissolved slurry based on the dilution effects and volumes of supernate and wash solutions removed. A trace level material balance showed greater than 97 percent recovery of americium-241 (from the beta dec

  4. Americium Transmutation Feasibility When Used as Burnable Absorbers - 12392

    International Nuclear Information System (INIS)

    The use of plutonium in Mixed Oxide (MOX) fuel in traditional Pressurized Water Reactor (PWR) assemblies leads to greater americium production which is not addressed in MOX recycling. The transuranic nuclides (TRU) contribute the most to the radiotoxicity of nuclear waste and a reduction of the TRU stockpile would greatly reduce the overall radiotoxicity of what must be managed. Am-241 is a TRU of particular concern because it is the dominant contributor of total radiotoxicity for the first 1000 years in a repository. This research explored the feasibility of transmuting Am-241 by using varying amounts in MOX rods being used in place of burnable absorbers and evaluated with respect to the impact on incineration and transmutation of transuranics in MOX fuel as well as the impact on safety. This research concludes that the addition of americium to a non-uniform fuel assembly is a viable method of transmuting Am-241, holding down excess reactivity in the core while serving as a burnable poison, as well as reducing the radiotoxicity of high level waste that must be managed. The use of Am/MOX hybrid fuel assemblies to transmute americium was researched using multiple computer codes. Am-241 was shown in this study to be able to hold down excess reactivity at the beginning of cycle and shape the power distribution in the core with assemblies of varying americium content loaded in a pattern similar to the traditional use of assemblies with varying amounts of burnable absorbers. The feasibility, safety, and utility of using americium to create an Am/MOX hybrid non-uniform core were also evaluated. The core remained critical to a burnup of 22,000 MWD/MTM. The power coefficient of reactivity as well as the temperature and power defects were sufficiently negative to provide a prompt feedback mechanism in case of a transient and prevent a power excursion, thus ensuring inherent safety and protection of the core. As shown here as well as many other studies, this non

  5. Removal of americium from effluent generated during the purification of plutonium by anion exchange

    Energy Technology Data Exchange (ETDEWEB)

    Noronha, Donald M.; Pius, Illipparambil C.; Chaudhury, Satyajeet [Bhabha Atomic Research Centre, Mumbai (India). Fuel Chemistry Div.

    2015-07-01

    Studies have been carried out on removal of americium from the effluent generated during anion exchange purification of plutonium. Americium 241, generated by the beta decay of Plutonium-241, is the major source of a activity in this highly acidic effluent and its removal would render the waste easily disposable. A simple and effective co-precipitation method, using thorium oxalate has been investigated for the treatment of this alpha active aqueous waste. Experiments have been carried out to identify optimum conditions to obtain high percentage co-precipitation with minimum amount of co-precipitant. Efforts were carried out to correlate the optimum conditions of co-precipitation of americium obtained in these experiments with solubility of thorium oxalate and americium oxalate calculated from solubility products of these compounds, stability constants of thorium and americium oxalate complexes taken from literature. The saturation capacity of thorium oxalate for Am(III) was also calculated by analyzing the K{sub d} value data using Langmuir adsorption equation. The strong tendency of americium to get co-precipitated and the high capacity exhibited by thorium oxalate for the uptake of americium indicate feasibility of using this method for the treatment of anion exchange effluent.

  6. Removal of americium from effluent generated during the purification of plutonium by anion exchange

    International Nuclear Information System (INIS)

    Studies have been carried out on removal of americium from the effluent generated during anion exchange purification of plutonium. Americium 241, generated by the beta decay of Plutonium-241, is the major source of a activity in this highly acidic effluent and its removal would render the waste easily disposable. A simple and effective co-precipitation method, using thorium oxalate has been investigated for the treatment of this alpha active aqueous waste. Experiments have been carried out to identify optimum conditions to obtain high percentage co-precipitation with minimum amount of co-precipitant. Efforts were carried out to correlate the optimum conditions of co-precipitation of americium obtained in these experiments with solubility of thorium oxalate and americium oxalate calculated from solubility products of these compounds, stability constants of thorium and americium oxalate complexes taken from literature. The saturation capacity of thorium oxalate for Am(III) was also calculated by analyzing the Kd value data using Langmuir adsorption equation. The strong tendency of americium to get co-precipitated and the high capacity exhibited by thorium oxalate for the uptake of americium indicate feasibility of using this method for the treatment of anion exchange effluent.

  7. Selective leaching studies of deep-sea sediments loaded with americium, neptunium and plutonium

    International Nuclear Information System (INIS)

    A series of selective leaching experiments were undertaken to investigate the solid phase speciation and distribution of americium, neptunium and plutonium which had been experimentally loaded onto different marine sediment types. The chemical leaches employed showed rather poor selectivity but certain trends were evident. Adsorption was not by ion exchange. Americium showed a preferential affinity for carbonate and plutonium for organic matter. Neptunium appeared to have no preferential affinities. Americium was sorbed by acetic acid residues (CaCO3 removed) and by unleached carbonate-rich sediments with equal efficiency. This indicates that it is able to diversify its solid phase affinity/distribution depending upon which solid phases are available. (author)

  8. Solubility of americium collected on an aerosol filter

    International Nuclear Information System (INIS)

    Kinetics of dissolution of undefined americium aerosol in simulated serum ultrafiltrate was studied. 241Am was present in aerosol collected at a workplace, where an intake of 241Am had occurred formerly. Dissolution experiments in four parts of an aerosol filter were carried out either in ambient air or under CO2 and pH was kept within physiological range. Two?phase kinetics was found in both cases with dissolution half?times for rapid and slow phases ranging from 0.16 to 0.23 d and from 150 to 500 d, respectively. Regardless data dispersion, found half?times justify use of class M model in intake assessment. (author)

  9. The 1976 Hanford Americium Accident: Then and Now

    Energy Technology Data Exchange (ETDEWEB)

    Carbaugh, Eugene H.

    2013-10-02

    The 1976 chemical explosion of an 241Am ion exchange column at a Hanford Site waste management facility resulted in the extreme contamination of a worker with 241Am, nitric acid and debris. The worker underwent medical treatment for acid burns, as well as wound debridement, extensive personal skin decontamination and long-term DTPA chelation therapy for decorporation of americium-241. Because of the contamination levels and prolonged decontamination efforts, care was provided for the first three months at the unique Emergency Decontamination Facility with gradual transition to the patient’s home occurring over another two months. The medical treatment, management, and dosimetry of the patient have been well documented in numerous reports and journal articles. The lessons learned with regard to patient treatment and effectiveness of therapy still form the underlying philosophy of treatment for contaminated injuries. Changes in infrastructure and facilities as well as societal expectations make for interesting speculation as to how responses might differ today.

  10. Separation of americium from curium by oxidation and ion exchange.

    Science.gov (United States)

    Burns, Jonathan D; Shehee, Thomas C; Clearfield, Abraham; Hobbs, David T

    2012-08-21

    Nuclear energy has the potential to be a clean alternative to fossil fuels, but in order for it to play a major role in the US, many questions about the back end of the fuel cycle must be addressed. One of these questions is the difficult separation of americium from curium. Here, we report the oxidation of Am in two systems, perchloric acid and nitric acid and the affect of changing the acid has on the oxidation. K(d) values were observed and a direct separation factor was calculated and was seen to be as high as 20 for four metal(IV) pillared phosphate phosphonate inorganic organic hybrid ion exchange materials. These ion exchangers are characterized by very low selectivity for cations with low charge but extremely high uptake of ions of high charge. PMID:22827724

  11. Monte Carlo modeling of spallation targets containing uranium and americium

    International Nuclear Information System (INIS)

    Neutron production and transport in spallation targets made of uranium and americium are studied with a Geant4-based code MCADS (Monte Carlo model for Accelerator Driven Systems). A good agreement of MCADS results with experimental data on neutron- and proton-induced reactions on 241Am and 243Am nuclei allows to use this model for simulations with extended Am targets. It was demonstrated that MCADS model can be used for calculating the values of critical mass for 233,235U, 237Np, 239Pu and 241Am. Several geometry options and material compositions (U, U + Am, Am, Am2O3) are considered for spallation targets to be used in Accelerator Driven Systems. All considered options operate as deep subcritical targets having neutron multiplication factor of k∼0.5. It is found that more than 4 kg of Am can be burned in one spallation target during the first year of operation

  12. Pretreatment of americium/curium solutions for vitrification

    International Nuclear Information System (INIS)

    Vitrification will be used to stabilize an americium/curium (Am/Cm) solution presently stored in F-Canyon for eventual transport to the heavy isotope programs at Oak Ridge National Laboratory. Prior to vitrification, an in-tank oxalate precipitation and a series of oxalic/nitric acid washes will be used to separate these elements and lanthanide fission products from the bulk of the uranium and metal impurities present in the solution. Pretreatment development experiments were performed to understand the behavior of the lanthanides and the metal impurities during the oxalate precipitation and properties of the precipitate slurry. The results of these experiments will be used to refine the target glass composition allowing optimization of the primary processing parameters and design of the solution transfer equipment

  13. Plutonium and americium in sediments of Lithuanian lakes

    International Nuclear Information System (INIS)

    The assessment of contribution of the global and the Chernobyl NPP (Nuclear Power Plant) accident plutonium and americium to plutonium pollution in sediments of Lithuanian lakes is presented. Theoretical evaluation of activity ratios of 238Pu/239+240Pu and 241Pu/239+240Pu in the reactor of unit 4 of the Chernobyl NPP before the accident was performed by means of the ORIGEN-ARP code from the SCALE 4.4A program package. Non-uniform distribution of radionuclides in depositions on the Lithuanian territory after nuclear weapon tests and the Chernobyl NPP accident is experimentally observed by measuring the lake sediment pollution with actinides. The activity concentration of sediments polluted with plutonium ranges from 2.0 ± 0.5 Bq/kg d.w. (dry weight) in Lake Asavelis to 14 ± 2 Bq/kg d.w. in Lake Juodis. The ratio of activity concentrations of plutonium isotopes 238Pu/239+240Pu measured by α-spectrometry in the 10-cm-thick upper layer of bottom sediment varies from 0.03 in Lake Juodis to 0.3 in Lake Zuvintas. The analysis of the ratio values shows that the deposition of the Chernobyl origin plutonium is prevailing in southern and south-western regions of Lithuania. Plutonium of nuclear weapon tests origin in sediments of lakes is observed on the whole territory of Lithuania, and it is especially distinct in central Lithuania. The americium activity due to 241Pu decay after the Chernobyl NPP accident and global depositions in bottom sediments of Lithuanian lakes has been evaluated to be from 0.9 to 5.7 Bq/kg. (author)

  14. Kinetic parameters of transformation of americium and plutonium physicochemical forms in podsol soils

    International Nuclear Information System (INIS)

    Kinetic parameters of transformation of americium and plutonium physicochemical forms have been estimated and the prognosis of fixing and remobilization of these nuclides in podsol soils have been made on that basis in the work. (authors)

  15. Calibration procedures for in vivo sodium iodide spectrometry of plutonium and americium in the human lung

    International Nuclear Information System (INIS)

    This paper describes the calibration techniques and associated error analysis for the in vivo measurement by NaI spectrometry of heavy elements in the lung, specifically plutonium and americium. A very brief description of the instrumentation system is included

  16. Relativistic density functional theory modeling of plutonium and americium higher oxide molecules

    Science.gov (United States)

    Zaitsevskii, Andréi; Mosyagin, Nikolai S.; Titov, Anatoly V.; Kiselev, Yuri M.

    2013-07-01

    The results of electronic structure modeling of plutonium and americium higher oxide molecules (actinide oxidation states VI through VIII) by two-component relativistic density functional theory are presented. Ground-state equilibrium molecular structures, main features of charge distributions, and energetics of AnO3, AnO4, An2On (An=Pu, Am), and PuAmOn, n = 6-8, are determined. In all cases, molecular geometries of americium and mixed plutonium-americium oxides are similar to those of the corresponding plutonium compounds, though chemical bonding in americium oxides is markedly weaker. Relatively high stability of the mixed heptoxide PuAmO7 is noticed; the Pu(VIII) and especially Am(VIII) oxides are expected to be unstable.

  17. Distribution of uranium, americium and plutonium in the biomass of freshwater macrophytes

    Energy Technology Data Exchange (ETDEWEB)

    Zotina, T.A.; Kalacheva, G.S.; Bolsunovsky, A.YA. [Institute of Biophysics SB RAS, Akademgorodok, Krasnoyarsk (Russian Federation)

    2010-07-01

    Accumulation of uranium ({sup 238}U), americium ({sup 241}Am) and plutonium ({sup 242}Pu) and their distribution in cell compartments and biochemical components of the biomass of aquatic plants Elodea canadensis, Ceratophyllum demersum, Myrioplyllum spicatum and aquatic moss Fontinalis antipyretica have been investigated in laboratory batch experiments. Isotopes of uranium, americium and plutonium taken up from the water by Elodea canadensis apical shoots were mainly absorbed by cell walls, plasmalemma and organelles. A small portion of isotopes (about 6-13 %) could be dissolved in cytoplasm. The major portion (76-92 %) of americium was bound to cell wall cellulose-like polysaccharides of Elodea canadensis, Myriophyllum spicatum, Ceratophyllum demersum and Fontinalis antipyretica, 8-23 % of americium activity was registered in the fraction of proteins and carbohydrates, and just a small portion (< 1%) in lipid fraction. The distribution of plutonium in the biomass fraction of Elodea was similar to that of americium. Hence, americium and plutonium had the highest affinity to cellulose-like polysaccharides in Elodea biomass. Distribution of uranium in the biomass of Elodea differed essentially from that of transuranium elements: a considerable portion of uranium was recorded in the fraction of protein and carbohydrates (51 %). From our data we can assume that uranium has higher affinity to carbohydrates than proteins. (authors)

  18. Separation of curium and americium microquantities by chromatographic method with introduction of separating ions. 2. Effect of cadmium ion quantity and method of it introduction in the system on efficiency of curium and americium separation

    International Nuclear Information System (INIS)

    Effect of fractionating cadmium ion and a method of it introduction in the system on efficiency of separation of curium and americium with the use of NTA solutions as an eluent is investigated. It is established that in contrast to mutual sorption of curium, americium and cadmium their selective sorption contributes more complete separation of curium and americium. It is shown that growth of quantity of introduced cadmium increased efficiency of separation. Elution rate not products effect on separation process

  19. Americium(3) solvent extraction by oxides of dialkyl(diaryl)[dialkylcarbamoylmethyl]phosphines (CMPO) from perchloric acid solutions

    International Nuclear Information System (INIS)

    Extraction of americium(3) from perchloric acid solutions by CMPO was investigated. It is shown that americium(3) is much more effectively extracted from perchloric acid solutions, than from nitric acid ones, and increase in americium distribution coefficient depends considerably on reagent nature. As a consequence, anomalous aryl effect increases significantly in perchloric acid solutions. The value of anomalous aryl effect depends directly on stoichiometry of extracted complexes in nitric acid and perchloric acid media. Conditions for extractional concentration of americium up to the 100-fold one with small reagent consumption were suggested

  20. Extraction of Americium(III) by diglycolamides in ionic liquids

    International Nuclear Information System (INIS)

    In the present work, the extraction behavior of Am(lII) in the three isomeric DGAs, TODGA, DEHDODGA and TEHDGA in two ionic liquids, 1-butyl-3-methylimidazolium bis(triflouromethane sulphonyl)imide (C4mimNTf2) and 1-butyl-1-methylpyrrolidinium bis(triflouromethanesulphonyl)imide (C4mpyNTf2) is compared. The distribution ratio of americium was determined at various acidities ranging from 1M to 8M. The distribution values were found to decrease with increase in aqueous phase acidity upto 3M. The DAm values then marginally increased with increase of acidity from 3 to 4M followed by a decrease in distribution values. The distribution ratio obtained for various DGAs followed the order TEHDGA < TODGA < DEHDODGA at aqueous phase acidities ranging from 1-4 M. When the aqueous nitric acid concentration was higher than 4M, the distribution values followed the order DEHDODGA < TEHDGA < TODGA. The anomalous behaviour of unsymmetrical diglycolamide in ionic liquid medium was investigated by IR spectroscopy. The study revealed that the unprotonated fraction of DGA (i.e. the free DGA) increased in the order TEHDGA < TODGA < DEHDODGA, which seems to be responsible for the observed anomalous extraction trend in DEHDODGA in ionic liquid medium

  1. Extraction of americium and europium by CMPO-substituted adamantylcalixarenes

    International Nuclear Information System (INIS)

    Eight p-adamantylcalix[4]arene derivatives, bearing four CMPO-like functions [-(CH2)n-NH-C(O)-CH2-P(O)Ph2] at the wide (4a,b, n = 0, 1) or narrow (5a-c and 6a-c, n = 2-4) rims were synthesized for the first time. Studies of the extraction of americium(III) and europium(III) from 3 M HNO3 solutions to organic phases (dichloromethane, m-nitro-trifluoromethylbenzene) showed: (i) The extraction ability for all the adamantylcalixarene ligands is much better than for their monomeric analogues -N-(1-adamantyl)-, N-(1-adamantylmethyl)- and N,N-(dibutyl)carbamoylmethyldiphenylphosphine oxides 7a, 7b, 8; (ii) The extraction percentage increases strongly with increasing length of the spacer for all types of ligands 4-6, and best extraction results were found for 4b (n = 1) and 5c (n = 4); (iii) The separation coefficient DAm/DEu for the investigated compounds did not exceed 2, which is close to the narrow rim CMPO calixarenes, studied earlier; (iv) Variation of the spacer length between CMPO groups attached to the 1,3- and 2,4-positions of the calixarene platform in 6 did not lead to appreciably improved extractants, neither with respect to the extraction abilities (D) nor to the selectivities (DAm/DEu). (orig.)

  2. Effect of americium-241 on luminous bacteria. Role of peroxides

    Energy Technology Data Exchange (ETDEWEB)

    Alexandrova, M., E-mail: maka-alexandrova@rambler.r [Siberian Federal University, Svobodny 79, 660041 Krasnoyarsk (Russian Federation); Rozhko, T. [Siberian Federal University, Svobodny 79, 660041 Krasnoyarsk (Russian Federation); Vydryakova, G. [Institute of Biophysics SB RAS, Akademgorodok 50, 660036 Krasnoyarsk (Russian Federation); Kudryasheva, N. [Siberian Federal University, Svobodny 79, 660041 Krasnoyarsk (Russian Federation); Institute of Biophysics SB RAS, Akademgorodok 50, 660036 Krasnoyarsk (Russian Federation)

    2011-04-15

    The effect of americium-241 ({sup 241}Am), an alpha-emitting radionuclide of high specific activity, on luminous bacteria Photobacterium phosphoreum was studied. Traces of {sup 241}Am in nutrient media (0.16-6.67 kBq/L) suppressed the growth of bacteria, but enhanced luminescence intensity and quantum yield at room temperature. Lower temperature (4 {sup o}C) increased the time of bacterial luminescence and revealed a stage of bioluminescence inhibition after 150 h of bioluminescence registration start. The role of conditions of exposure the bacterial cells to the {sup 241}Am is discussed. The effect of {sup 241}Am on luminous bacteria was attributed to peroxide compounds generated in water solutions as secondary products of radioactive decay. Increase of peroxide concentration in {sup 241}Am solutions was demonstrated; and the similarity of {sup 241}Am and hydrogen peroxide effects on bacterial luminescence was revealed. The study provides a scientific basis for elaboration of bioluminescence-based assay to monitor radiotoxicity of alpha-emitting radionuclides in aquatic solutions. - Highlights: {yields} Am-241 in water solutions (A = 0.16-6.7 kBq/L) suppresses bacterial growth.{yields} Am-241 (A = 0.16-6.7 kBq/L) stimulate bacterial luminescence. {yields} Peroxides, secondary radiolysis products, cause increase of bacterial luminescence.

  3. Separation and determination of americium in low-level alkaline waste of NPP origin

    Science.gov (United States)

    Todorov, B.; Djingova, R.; Nikiforova, A.

    2006-01-01

    The aim of this work is to develop a short and cost-saving procedure for the determination of 241Am in sludge sample of the alkaline low-level radioactive waste (LL LRAW) collected from Nuclear Power Plant “Kozloduy”. The determination of americium was a part of a complex analytical approach, where group actinide separation was achieved. An anion exchange was used for separation of americium from uranium, plutonium and iron. For the separation of americium extraction with diethylhexyl phosphoric acid (DEHPA) was studied. The final radioactive samples were prepared by micro co-precipitation with NdF3, counted by alpha and gamma spectrometry. The procedure takes 2 hours. The recovery yield of the procedure amounts to (95 ± 1.5)% and the detection limit is 53 mBq/kg 241Am (t=150 000 s). The analytical procedure was applied for actual liquid wastes and results were compared to standard procedure.

  4. Americium 241 in vegetation of natural biocenoses and agrocenoses on Belarus territories contaminated with Chernobyl fall-out

    International Nuclear Information System (INIS)

    As a result of beta-decay of plutonium 241 the content of americium 241 increases progressively in soils, contaminated with Chernobyl trans uranium elements. Americium 241 displayed higher (0,5 - 1,5-fold) biological mobility than isotopes of plutonium 239, 240. Activity of americium 241 in surface phyto mass of wild and cultural plants varies from 0,04 to 5,9 Bq/kg of dry weight. Americium 241 contribution to the total trans uranium elements contamination of plants made up 60 - 80% in 1996 - 1998. Investigation of trials from the areas adjacent to the 30-km zone showed that mobility of americium 241 and plutonium was 5 - 15 times as high as in the zone

  5. Isotopic and elemental composition of plutonium/americium oxides influence pulmonary and extra-pulmonary distribution after inhalation in rats

    International Nuclear Information System (INIS)

    The biodistribution of plutonium and americium has been studied in a rat model after inhalation of two PuO2 powders in lungs and extra-pulmonary organs from 3 d to 3 mo. The main difference between the two powders was the content of americium (approximately 46% and 4.5% of total alpha activity). The PuO2 with a higher proportion of americium shows an accelerated transfer of activity from lungs to blood as compared to PuO2 with the lower americium content, illustrated by increased urinary excretion and higher bone and liver actinide retention. The total alpha activity measured reflects mostly the americium biological behavior. The activity contained in epithelial lining fluid, recovered in the acellular phase of broncho-alveolar lavages, mainly contains americium, whereas plutonium remains trapped in macrophages. Epithelial lining fluid could represent a transitional pulmonary compartment prior to translocation of actinides to the blood and subsequent deposition in extra-pulmonary retention organs. In addition, differential behaviors of plutonium and americium are also observed between the PuO2 powders with a higher dissolution rate for both plutonium and americium being obtained for the PuO2 with the highest americium content. Our results indicate that the biological behavior of plutonium and americium after translocation into blood differ two-fold: (1) for the two actinides for the same PuO2 aerosol, and (2) for the same actinide from the two different aerosols. These results highlight the importance of considering the specific behavior of each contaminant after accidental pulmonary intake when assessing extra-pulmonary deposits from the level of activity excreted in urine or for therapeutic strategy decisions. (authors)

  6. Determination of trace concentration of uranium in americium oxide samples by ICP-AES

    International Nuclear Information System (INIS)

    A solvent extraction method has been developed for the determination of uranium (200-2000 ppm) in americium oxide samples. The method involves the quantitative separation of uranium from americium matrix using mixed solvent comprising 1.1M tri-n-butyl phosphate (TBP) +1% trialkyl phosphine oxide (TRPO) + 0.3 M tertiary butyl hydroquinone (TBHQ) in n-dodecane. Uranium from the organic is stripped into the aqueous phase with 0.8 M oxalic acid and determined by ICP-AES. The reliability of the method was ascertained by analytical recovery, which is found to be nearly 100%. (author)

  7. Adsorption-desorption characteristics of plutonium and americium with sediment particles in the estuarine environment: studies using plutonium-237 and americium-241

    International Nuclear Information System (INIS)

    The particle formation of plutonium and americium, their adsorption onto fresh water sediments and the desorption from the sediments in sea water were studied in the Laboratory under simulated river-estuary conditions, using γ-emitting plutonium-237 and americium-241. The results of the experiments show that the particle formation of plutonium depends on its valence states, on pH and on the salinity of the medium. For river water at pH4, some 25%, 20% and 30% of the added 237Pu was in particulate form, larger than 0.45 μm, for Pu (III), Pu (IV) and Pu (VI), respectively, while 65%, 90% and 50% of the respective valence states was associated with particles at pH 8. In sea water the general pattern remains similar, although Pu (VI) is more soluble in sea water owing to higher ligand concentrations for carbonate and bicarbonate complexes. The pH-dependency of particle formation of Am (III) is more steep than that of plutonium and seems to be influenced by colloidal substances occurring in the experimental media. The adsorption-desorption characteristics of plutonium and americium with the sediment in river water as well as sea water reflect the characteristics of their particle formation, being dependent upon such properties as valence states, the pH and salinity of the medium. A sewage effluent added to the media has small but measurable effects on the adsorption-desorption processes of plutonium. (author)

  8. Impact of ionic liquids on europium and americium extraction by an upper rim phosphorylated calixarene

    International Nuclear Information System (INIS)

    The solvent extraction of europium and americium using the calixarene 5,11,17,23-tetrakis[dipropylphosphinylmethyl] 25,26,27,28-tetrapropoxycalix[4]arene (conical conformation) in the presence of ionic liquids with different natures was studied. It was shown that upper rim phosphorylated calixarene is able to extract europium and americium from nitric acid to dichloroethane by forming a 1:1 complex without the addition of ionic liquids. The distribution coefficients of americium are higher than those of europium in this case, but the isolation degrees of both elements are insufficient for this system to be useful in extraction technologies. The addition of the ionic liquid trihexyl(tetradecyl)phosphonium hexafluorophosphate increases the europium distribution coefficient by values ranging from twofold to more than two orders of magnitude at ionic liquid concentrations of 1 and 50 %, respectively. The values of the distribution coefficients for americium are increased by approximately 25-fold after a 50 % addition of the ionic liquid. (author)

  9. Understanding the Chemistry of Uncommon Americium Oxidation States for Application to Actinide/Lanthanide Separations

    Energy Technology Data Exchange (ETDEWEB)

    Leigh Martin; Bruce J. Mincher; Nicholas C. Schmitt

    2007-09-01

    A spectroscopic study of the stability of Am(V) and Am(VI) produced by oxidizing Am(III) with sodium bismuthate is presented, varying the initial americium concentration, temperature and length of the oxidation was seen to have profound effects on the resultant solutions.

  10. Speciation and bioavailability of plutonium and americium in the Irish Sea and other marine ecosystems

    International Nuclear Information System (INIS)

    Since the late 1960s, the Irish Sea has become a repository for a variety of radio-elements originating mainly in discharges from the British Nuclear Fuels (BNF) plc. Sellafield reprocessing complex located on the Cumbrian coast. In particular, transuranium nuclides such as plutonium, americium and curium (the main constituents of the α-emitting discharges) have become incorporated into every marine compartment by a variety of mechanisms, many of which are not well understood. Although extensive studies have been carried out in the near-field (eastern Irish Sea, especially in the vicinity of the discharge point and collateral muddy sediments), comparatively little had been done to assess the long-term behaviour and bioavailability of plutonium and americium in the far-field, e.g., the western Irish Sea, prior to the present study. In this dissertation, the results of an extensive research programme, undertaken in order to improve and refine our understanding of the behaviour of plutonium and americium in the marine environment, are presented. Specifically, the thesis details the results of (and conclusions deduced from) a series of experiments in which the physical and chemical speciation, colloidal association, mobility and bioavailability of plutonium and americium were examined in diverse environments including the Irish Sea and the Mediterranean. (author)

  11. Evaluation of the readsorption of plutonium and americium in dynamic fractionations of environmental solid samples

    DEFF Research Database (Denmark)

    Petersen, Roongrat; Hou, Xiaolin; Hansen, Elo Harald

    2008-01-01

    extractions. The degree of readsorption in dynamic and conventional batch extraction systems are compared and evaluated by using a double-spiking technique. A high degree of readsorption of plutonium and americium (>75%) was observed in both systems, and they also exhibited similar distribution patterns...

  12. Extraction chromatographic recovery of americium from acidic raffinate solutions using CMPO adsorbed on Chromosorb-102

    International Nuclear Information System (INIS)

    Microgram amounts of americium have been separated and purified from large amounts of uranium present in effluent solutions resulting from the anion-exchange columns during the purification and recovery of plutonium by using TBP extraction followed by extraction chromatography using CMPO adsorbed on Chromosorb-102. (author). 4 refs., 1 tab

  13. Cesium-137 and americium-241 distribution by granulometric fractions of soil at Azgir test site grounds

    International Nuclear Information System (INIS)

    In measurements of radionuclide specific content in surface soil layer of contaminated territories it is important to determine in what agglomerations of soil particles there is the highest radionuclide concentration. For this purpose granulometric composition of soil at Azgir test site was studied and cesium-137 and americium-241 distribution by soil fractions was researched. (author)

  14. Development of analytical methods for the separation of plutonium, americium, curium and neptunium from environmental samples

    OpenAIRE

    Salminen, Susanna

    2009-01-01

    In this work, separation methods have been developed for the analysis of anthropogenic transuranium elements plutonium, americium, curium and neptunium from environmental samples contaminated by global nuclear weapons testing and the Chernobyl accident. The analytical methods utilized in this study are based on extraction chromatography. Highly varying atmospheric plutonium isotope concentrations and activity ratios were found at both Kurchatov (Kazakhstan), near the former Semipalatinsk...

  15. Determination of specific activity of americium and plutonium in selected environmental samples

    International Nuclear Information System (INIS)

    The aim of this work was development of method for determination of americium and plutonium in environmental samples. Developed method was evaluated on soil samples and after they was applied on selected samples of fishes (smoked mackerel, herring and fillet from Alaska hake). The method for separation of americium is based on liquid separation with Aliquate-336, precipitation with oxalic acid and using of chromatographic material TRU-SpecTM.The intervals of radiochemical yields were from 13.0% to 80.9% for plutonium-236 and from 10.5% to 100% for americium-241. Determined specific activities of plutonium-239,240 were from (2.3 ± 1.4) mBq/kg to (82 ± 29) mBq/kg, the specific activities of plutonium-238 were from (14.2 ± 3.7) mBq/kg to (708 ± 86) mBq/kg. The specific activities of americium-241 were from (1.4 ± 0.9) mBq/kg to (3360 ± 210) mBq/kg. The fishes from Baltic Sea as well as from North Sea show highest specific activities then fresh-water fishes from Slovakia. Therefore the monitoring of alpha radionuclides in foods imported from territories with nuclear testing is recommended

  16. Application of hollow fiber supported liquid membrane for the separation of americium from the analytical waste

    International Nuclear Information System (INIS)

    Americium from analytical solid waste containing U and metallic impurities was separated using hollow fiber supported liquid membrane (HFSLM) technique impregnated with DHOA-TODGA from nitric acid medium. An aliquot of 5 g of the solid waste containing Am (19.95 mg) as minor actinide and of U (2,588 mg), Fe (1,360 mg), Ca (1,810 mg) and Na (3,130 mg) as major impurities was processed. The feed solution obtained after the dissolution of the residue in ∼4 M HNO3 was passed through HFSLM module. In the first stage using 1 M DHOA-dodecane was used for the separation of Am from other impurities. Though, majority of the elements were separated in this cycle, Ca was co extracted along with the americium. CMPO extraction chromatographic technique was used for further separation of americium from Ca. Significant decontamination factors were achieved in this three step separation process with respect to U, Fe, Na and Ca with ∼77 % recovery of americium. (author)

  17. Determination of α-emitters (plutonium, americium, curium ...) in feces and urine ashes

    International Nuclear Information System (INIS)

    A description is given of the methods used to determine a number of radionuclides to be found in feces and urine, and obtain samples thin enough for counting and α-spectrometry. These methods can be applied to plutonium, americium and curium especially

  18. Upper Limits to Americium Concentration in Medium Size Sodium Cooled Fast Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Y.P.; Wallenius, J. [Royal Institute of Technology (KTH), AlbaNova University Centre, S-106 91, Stockholm (Sweden)

    2009-06-15

    The fastest way to realize transmutation of minor actinides would be using existing reactor types, adding some proper modifications to allow for insertion of MA in the fuel. According to calculations by Fazio and co-workers, the consumption rate of TRU in a low conversion ratio fast reactor may reach 70-75 % of that of an ADS with uranium free fuel [1]. However, americium introduction brings a negative influence on several safety parameters such as {beta}{sub eff}, Doppler coefficient, coolant temperature coefficient and void worth. Therefore the upper limit of americium that can be included into the fuel needs to be carefully evaluated. In this paper, fast reactor fuels with various minor actinide fractions are loaded into a SAS4A model of the semi-commercial BN600 reactor. Unprotected loss of flow (ULOF) and transient over power (UTOP) accidents are modelled using safety parameters obtained from Monte Carlo simulations as well as from the deterministic calculations published by Fazio et al. Applying the latter parameters (obtained with VARI3D), the upper limit to MA concentration in the fuel of a medium sized SFR of BN-600 type appears at 12%, corresponding to 8% of americium. We note however that the Doppler constants displayed by Fazio et al for MA concentrations above 10% have a considerably larger magnitude than those obtained with MCNP. Applying the safety parameters obtained with Monte Carlo simulations and updated nuclear data evaluations, we find that the upper limit to the americium concentration allowing to survive a ULOF is about half of that inferred by the use of parameters from VARI-3D. Since such a difference has a major impact on the predicted americium transmutation capability of SFR, it is of high priority to analyse the reasons for the apparent discrepancies. We note here that the major contribution to the Doppler feedback comes from capture resonance in U-238 and Pu-240 residing below the sodium scattering resonance located at 3 keV, and that

  19. Effect of bone-status on retention and distribution of americium-241 in bones of small rodents

    International Nuclear Information System (INIS)

    Forced physical exercise before and after application of americium-241 resulted in only small changes in bone-structure and behaviour of the radionuclide in bone. Feeding of a low phosphorus or low calcium diet resulted in an increased excretion of americium from bone, whereby Zn-DTPA as chelating agent removed an additional fraction of the radionuclide from bone. Low calcium diet and simultaneous continuous infusion of pharmacological doses of vitamin D-hormones didn't increase the excretion of americium more than the low calcium diet alone. (orig.)

  20. Interaction and diffusion transport of americium in soils

    International Nuclear Information System (INIS)

    The final disposal of High Level Radioactive Wastes (HLRW) is based on its long-term storage in underground facilities located in geological stable sites with a multi-barrier system, the so called Deep Geological Repositories (DGR), that will keep HLRW confined for >10.000 years. After this period of time, leachates rich in long-live radioisotopes might escape from DGR and start to transport towards the biosphere. There is still a lack of information concerning the interaction and transport in soils of some radionuclides present in HLRW, especially for radionuclides that present a high sorption, such as americium (Am). Having reliable information about the mobility of radionuclides in soils is crucial in order to develop risk assessment models and to take proper decisions in case of soil contamination. The aim of the present work was, by means of laboratory scale experiments, to study the interaction and, for first time, to evaluate the diffusion transport of 241Am in soils. The 241Am interaction in soils was assessed by applying sorption batch assays to 20 soil samples with contrasted edaphic properties which allowed us to quantify the solid-liquid distribution coefficient (Kd) and desorption percentage. Kd (Am) values ranged from 103 to 105 L kg-1 and desorption percentages were always less than 2% which denoted a high capacity of the soil to incorporate the Am and a low reversibility of the sorption process. The influence of soil properties in 241Am interaction was studied by means of multiple linear and multivariate regressions. Although a single correlation between Kd (Am) values and a soil property was not found, the main properties affecting 241Am interaction in soils were soil pH, carbonate and organic matter contents in the soil. Finally, additional batch assays at different controlled pH were done to study Am sorption as a function of the contact solution pH. A variation of the Am sorption capacity was observed in all soils due to the dissolution of soil

  1. Interaction and diffusion transport of americium in soils

    Energy Technology Data Exchange (ETDEWEB)

    Ramirez-Guinart, Oriol; Rigol, Anna; Vidal, Miquel [Analytical Chemistry department, Faculty of Chemistry, University of Barcelona, Marti i Franques 1-11, 08028, Barcelona (Spain)

    2014-07-01

    The final disposal of High Level Radioactive Wastes (HLRW) is based on its long-term storage in underground facilities located in geological stable sites with a multi-barrier system, the so called Deep Geological Repositories (DGR), that will keep HLRW confined for >10.000 years. After this period of time, leachates rich in long-live radioisotopes might escape from DGR and start to transport towards the biosphere. There is still a lack of information concerning the interaction and transport in soils of some radionuclides present in HLRW, especially for radionuclides that present a high sorption, such as americium (Am). Having reliable information about the mobility of radionuclides in soils is crucial in order to develop risk assessment models and to take proper decisions in case of soil contamination. The aim of the present work was, by means of laboratory scale experiments, to study the interaction and, for first time, to evaluate the diffusion transport of {sup 241}Am in soils. The {sup 241}Am interaction in soils was assessed by applying sorption batch assays to 20 soil samples with contrasted edaphic properties which allowed us to quantify the solid-liquid distribution coefficient (K{sub d}) and desorption percentage. K{sub d} (Am) values ranged from 10{sup 3} to 10{sup 5} L kg{sup -1} and desorption percentages were always less than 2% which denoted a high capacity of the soil to incorporate the Am and a low reversibility of the sorption process. The influence of soil properties in {sup 241}Am interaction was studied by means of multiple linear and multivariate regressions. Although a single correlation between K{sub d} (Am) values and a soil property was not found, the main properties affecting {sup 241}Am interaction in soils were soil pH, carbonate and organic matter contents in the soil. Finally, additional batch assays at different controlled pH were done to study Am sorption as a function of the contact solution pH. A variation of the Am sorption

  2. SKIN DOSIMETRY IN CONDITIONS OF ITS CONSTANT SURFACE CONTAMINATION WITH SOLUTIONS OF PLUTONIUM-239 AND AMERICIUM-241

    Directory of Open Access Journals (Sweden)

    E. B. Ershov

    2012-01-01

    Full Text Available The article considers, on the basis of experimental data, the issue of assessing dose burdens to the skin basal layer in conditions of its permanent contamination with solutions of plutonium-239 and americium-241 and subsequent decontamination.

  3. Metabolism of americium-241 in man: an unusual case of internal contamination of a child and his father

    International Nuclear Information System (INIS)

    The metabolism of americium-241 was studied during an 8-yr period of an adult male and his son who, at the ages of 50 and 4, respectively, were accidentally and unknowingly contaminated within their home by means of inhalation. Chelation therapy with Na3(Ca-DTPA) was more effective in enhancing the removal of americium-241 from the child than from his father

  4. Influence of biofilms on migration of uranium, americium and europium in the environment; Einfluss von Biofilmen auf das Migrationsverhalten von Uran, Americium und Europium in der Umwelt

    Energy Technology Data Exchange (ETDEWEB)

    Baumann, Nils; Zirnstein, Isabel; Arnold, Thuro

    2015-07-01

    The report on the influence of biofilms on migration of uranium, americium and europium in the environment deals with the contamination problems of uranium mines such as SDAG WISMUT in Saxonia and Thuringia. In mine waters microorganisms form a complex microbiological biocoenosis in spite of low pH values and high heavy metal concentrations including high uranium concentrations. The analyses used microbiological methods like confocal laser scanning microscopy and molecular-biological techniques. The interactions of microorganism with fluorescent radioactive heavy metal ions were performed with TRLFS (time resolved laser-induced fluorescence spectroscopy).

  5. Liquid-liquid extraction separation and sequential determination of plutonium and americium in environmental samples by alpha-spectrometry

    International Nuclear Information System (INIS)

    A procedure is described by which plutonium and americium can be determined in environmental samples. The sample is leached with nitric acid and hydrogen peroxide, and the two elements are co-precipitated with ferric hydroxide and calcium oxalate. The calcium oxalate is incinerated at 4500 and the ash is dissolved in nitric acid. Plutonium is extracted with tri-n-octylamine solution in xylene from 4M nitric acid and stripped with ammonium iodide/hydrochloric acid. Americium is extracted with thenoyltrifluoroacetone solution in xylene at pH 4 together with rare-earth elements and stripped with 1M nitric acid. Americium and the rare-earth elements thus separated are sorbed on Dowex 1 x 4 resin from 1M nitric acid in 93% methanol, the rare-earth elements are eluted with 0.1M hydrochloric acid/0.5M ammonium thiocyanate/80% methanol and the americium is finally eluted with 1.5M hydrochloric acid in 86% methanol. Plutonium and americium in each fraction are electro-deposited and determined by alpha-spectrometry. Overall average recoveries are 81% for plutonium and 59% for americium. (author)

  6. Electrodeposition of americium on a liquid cadmium cathode from a molten salt bath

    International Nuclear Information System (INIS)

    A high-activity experiment involving the electrode position of americium on a liquid cadmium cathode from a LiCl-KCl eutectic with about 3 g of AmO2 was conducted in a shielded cell in the ATALANTE complex. After describing the electrolyzer and the experimental conditions, the authors discuss the preparation of the LiCl-KCl-AmCl3 solution and briefly review its electrochemical properties. It was clearly confirmed that Am(III) reduction on an inert solid cathode occurs in two steps forming Am(II) before Am(0), whereas only one reduction step was observed on liquid cadmium. The main results of this study concern americium electrode position on the liquid cadmium cathode (recovery yields, current densities, problems encountered). The solvent properties of cadmium for actinide/lanthanide separation are discussed. (authors)

  7. Experimental Insight into the Radiation Resistance of Zirconia-Based Americium Ceramics

    International Nuclear Information System (INIS)

    Our works shows that the americium pyrochlore 241Am2Zr2O7 undergoes a phase transition to a defect-fluorite structure along with an unusual volume contraction when subjected to internal radiation from α-emitting actinides. Disorder relaxation proceeds through the simultaneous formation of cation anti sites and oxygen Frenkel pairs. X-ray absorption spectroscopy at the Am-LII and the Zr-K edges reveals that Am-O polyhedra show an increasing disorder with increasing exposure. In contrast, the Zr-O polyhedral units remain highly ordered, while rotating along edges and corners, thereby reducing the structural strain imposed by the growing disorder around americium. We believe it is this particular property of the compound that provides the remarkable resistance to radiation (≥9.4 * 1018) α-decay events g-1 or 0.80 dpa). (authors)

  8. Influence of some organic additives on the extractive separation of americium(III) by sulfoxides

    International Nuclear Information System (INIS)

    The solvent extraction behavior of americium(III) from aqueous nitrate media by two long-chain aliphatic sulfoxides has been examined systematically in the presence of several water-miscible organic solvents to study their possible synergistic effect on metal ion extraction. Methanol, ethanol, n- and isopropanol, n-butanol, dioxane, acetone, as well as acetonitrile, were employed as the organic component of the mixed (polar) phase. These additives affected the extraction to varying degrees. Extractability of Am increased 5 to 10-fold with increasing concentration of some of these additives, with the maximum enhancement being observed in the presence of acetone or acetonitrile. However, alcohols are generally very poor in this respect. Possible reasons for such behavior are briefly discussed. The distribution of several common contaminants was also investigated at the optimum condition for americium extraction

  9. Transmutation of americium and curium incorporated in zirconia-based host materials

    International Nuclear Information System (INIS)

    Presented are studies involving the incorporation of americium and curium in zirconia-based materials. First explored was the pseudo ternary system AmO2-ZrO2-Y2O3. It was determined that selected Y-CSZ materials can incorporate significant quantities of americium oxide and remain cubic single-phase. The cell parameters of these fluorite-type products were established to be linear with the AmO2 content. The Cm2O3-ZrO2 system was also investigated. It was found that at 25 mol% of CmO1.5, the Cm(III) stabilized zirconia in its cubic form (a = 5.21 ±0.01 Angstrom). At higher and lower concentrations, diphasic materials were encountered. At 50 mol% of CmO1.5, a pyrochlore oxide - Cm2Zr2O7 - is formed (a = 10.63 ±0.02 Angstrom). (author)

  10. Americium and samarium determination in aqueous solutions after separation by cation-exchange

    International Nuclear Information System (INIS)

    The concentration of trivalent americium and samarium in aqueous samples has been determined by means of alpha-radiometry and UV-Vis photometry, respectively, after chemical separation and pre-concentration of the elements by cation-exchange using Chelex-100 resin. Method calibration was performed using americium (241Am) and samarium standard solutions and resulted in a high chemical recovery for cation-exchange. Regarding, the effect of physicochemical parameters (e.g. pH, salinity, competitive cations and colloidal species) on the separation recovery of the trivalent elements from aqueous solutions by cation-exchange has also been investigated. The investigation was performed to evaluate the applicability of cation-exchange as separation and pre-concentration method prior to the quantitative analysis of trivalent f-elements in water samples, and has shown that the method could be successfully applied to waters with relatively low dissolved solid content. (author)

  11. Analysis of americium-beryllium neutron source composition using the FRAM code

    Energy Technology Data Exchange (ETDEWEB)

    Hypes, P. A. (Philip A.); Bracken, D. S. (David S.); Sampson, Thomas E.; Taylor, W. A. (Wayne A.)

    2002-01-01

    The FRAM code was originally developed to analyze high-resolution gamma spectra from plutonium items. Its capabilities have since been expanded to include analysis of uranium spectra. The flexibility of the software also enables a capable spectroscopist to use FRAM to analyze spectra in which neither plutonium nor uranium is present in significant amounts. This paper documents the use of FRAM to determine the {sup 239}Pu/{sup 241}Am, {sup 243}Am/{sup 241}Am, {sup 237}Np/{sup 241}Am, and {sup 239}Np/{sup 241}Am ratios in americium-beryllium neutron sources. The effective specific power of each neutron source was calculated from the ratios determined by FRAM in order to determine the americium mass of each of these neutron sources using calorimetric assay. We will also discuss the use of FRAM for the general case of isotopic analysis of nonplutonium, nonuranium items.

  12. Influence of environmental factors on the gastrointestinal absorption of plutonium and americium

    International Nuclear Information System (INIS)

    The absorption of plutonium and americium from the gastrointestinal tract was studied, using adult hamsters and rabbits. Both actinides were administered as inorganic compounds, as organic complexes with naturally occurring chelating agents, and in a biologically incorporated form in liver tissues. The absorption of the tetravalent and hexavalent forms of plutonium were compared and the effect of protracted administration at very low concentrations was investigated. In addition, plutonium uptake from contaminated sediments and grass, collected near a nuclear-fuel reprocessing plant, was measured. The results of these studies suggest that chronic exposure of man to plutonium and americium in food and water will not lead to any substantial increase in their gastrointestinal absorption above the values currently recommended by the International Commission on Radiological Protection to define the occupational exposure of workers

  13. Contemporary state of plutonium and americium in the soils of Palesse state radiation-ecological reserve

    International Nuclear Information System (INIS)

    Full text: At present, the most important alpha-emitting radionuclides of Chernobyl origin are Pu 238, Pu 239, Pu 240 and Am 241. They are classified as the most dangerous group of radionuclides in view of the long half-lives and high radiotoxicity. The main part of alpha-emitted radionuclides is located within the Palesse State Radiation-Ecological Reserve. One of the most important factors determining the radioecological situation in the contaminated ecosystems is the physicochemical forms of radionuclides in a soil medium. Radionuclide species determine the radionuclide entrance into the soil solutions, their redistribution in soil profiles and the 'soil - plant' and the 'soil - surface, ground or underground water' systems as well as spreading beyond the contaminated area. The present work is devoted to investigation of state and migration ability of plutonium and americium in soils of the Palesse state radiation-ecological reserve after more than 20 years from the Chernobyl accident. The objects of investigation were mineral and organic soils sampled in 2008 with the step of 5 cm to the depth of 25-30 cm. The forms of plutonium and americium distinguishing by association with the different components of soil and by potential for migration in the soil medium were studied using the method of sequential selective extraction according to the modified Tessier scheme. Activities of Pu 238, Pu 239, Pu 240 and Am 241 in the samples were determined by the method of radiochemical analysis with alpha-spectrometer radionuclide identification. The dominant part of plutonium and americium in the soils is in immobile forms. Nowadays, radionuclide portions in water soluble and reversibly bound forms do not exceed 9.4 % of radionuclide content in the soil. In mineral soil samples, the radionuclide portions in these fractions exceed the corresponding portions in organic ones. In both mineral and organic soils, the portions of mobile americium are higher than plutonium. The

  14. Standard test method for quantitative determination of americium 241 in plutonium by Gamma-Ray spectrometry

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    1994-01-01

    1.1 This test method covers the quantitative determination of americium 241 by gamma-ray spectrometry in plutonium nitrate solution samples that do not contain significant amounts of radioactive fission products or other high specific activity gamma-ray emitters. 1.2 This test method can be used to determine the americium 241 in samples of plutonium metal, oxide and other solid forms, when the solid is appropriately sampled and dissolved. 1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

  15. Fabrication of neptunium, plutonium, americium and curium metals for fuel research

    International Nuclear Information System (INIS)

    The techniques for the fabrication of actinide metals; neptunium, americium and curium called as minor actinides, and plutonium, are surveied in a viewpoint of the preparation of starting materials for fuel property measurements. In this report, the processes of the conversion to metals, purification et al. are reviewed. The concept related to the apparatus design is also proposed and the considerable subjects are discussed. (author)

  16. Final Radiological Assessment of External Exposure for CLEAR-Line Americium Recovery Operations

    Energy Technology Data Exchange (ETDEWEB)

    Davis, Adam C. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Belooussova, Olga N. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Hetrick, Lucas Duane [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2014-11-12

    Los Alamos National Laboratory is currently planning to implement an americium recovery program. The americium, ordinarily isotopically pure 241Am, would be extracted from existing Pu materials, converted to an oxide and shipped to support fabrication of americium oxide-beryllium neutron sources. These operations would occur in the currently proposed Chloride Extraction and Actinide Recovery (CLEAR) line of glove boxes. This glove box line would be collocated with the currently-operational Experimental Chloride Extraction Line (EXCEL). The focus of this document is to provide an in-depth assessment of the currently planned radiation protection measures and to determine whether or not further design work is required to satisfy design-goal and ALARA requirements. Further, this document presents a history of americium recovery operations in the Department of Energy and high-level descriptions of the CLEAR line operations to provide a basis of comparison. Under the working assumptions adopted by this study, it was found that the evaluated design appears to mitigate doses to a level that satisfies the ALARA-in-design requirements of 10 CFR 835 as implemented by the Los Alamos National Laboratory procedure P121. The analyses indicate that extremity doses would also meet design requirements. Dose-rate calculations were performed using the radiation transport code MCNP5 and doses were estimated using a time-motion study developed in consort with the subject matter expert. A copy of this report and all supporting documentation are located on the Radiological Engineering server at Y:\\Rad Engineering\\2013 PROJECTS\\TA-55 Clear Line.

  17. Fabrication of uranium–americium mixed oxide pellet from microsphere precursors: Application of CRMP process

    International Nuclear Information System (INIS)

    Highlights: • Dust free process for (U,Am)O2 transmutation target fabrication. • Synthesis of U0.9Am0.1O2 mixed oxide microspheres from ion exchange resin. • Fabrication of dense U0.9Am0.1O2 pellet with 95% TD from mixed oxide microspheres. - Abstract: Mixed uranium–americium oxides are one of the materials envisaged for Americium Bearing Blankets dedicated to transmutation in fast neutron reactors. Recently, several processes have been developed in order to validate fabrication flowchart in terms of material specifications such as density and homogeneity but also to suggest simplifications for lowering industrial costs and hazards linked to dust generation of highly contaminating and irradiating compounds. This study deals with the application of an innovative route using mixed oxide microspheres obtained from metal loaded resin bead calcination, called Calcined Resin Microsphere Pelletization (CRMP). The synthesis of mixed oxide microsphere precursor of U0.9Am0.1O2±δ is described as well as its characterisation. The use of this free-flowing precursor allows the pressing and sintering of one pellet of U0.9Am0.1O2±δ. The ceramic obtained was characterised and results showed that its microstructure is dense and homogeneous and its density attains 95% of the theoretical density. This study validates the scientific feasibility of the CRMP process applied to the fabrication of uranium and americium-containing materials

  18. Influence of dissolved organic substances in groundwater on sorption behavior of americium and neptunium

    International Nuclear Information System (INIS)

    Groundwaters typically contain dissolved organic carbon consisting largely of high molecular weight compounds of humic and fulvic acids. To evaluate whether these dissolved organic substances can enhance the tranport of radionuclides through the groundwater system, experiments were conducted to examine the sorption of americium and neptunium onto crushed basalt in the presence of dissolved humic- and fulvic-acid organic carbon introduced into synthetic groundwater. The partitioning experiments with synthetic groundwater show that increasing the concentration of either humic or fulvic acid in the water has a significant inhibiting effect on sorption of both americium and neptunium. At 220C, adsorption of these radionuclides, as measured by distribution ratios (the ratio of nuclide sorbed onto the solid to nuclide in solution at the end of the experiment), decreased by 25% to 50% by addition of as little as 1 mg/L dissolved organic carbon and by one to two orders of magnitude by addition of 100 to 200 mg/L dissolved organic carbon. Distribution ratios measured in solutions reacted at 900C similarly decreased with the addition of dissolved organic carbon but generally ranged from one to two orders of magnitude higher than those determined in the 220C experiment. These results suggest that organic carbon dissolved in deep groundwaters may significantly enhance the mobility of radionuclides of americium and neptunium. 23 references, 5 figures, 11 tables

  19. Bidentate organophosphorus extraction of americium and plutonium from Hanford Plutonium Reclamation Facility waste

    Energy Technology Data Exchange (ETDEWEB)

    Schulz, W.W.

    1974-09-01

    Applicability of bidentate organiphosphorus reagents to recovery of americium and plutonium from Hanford's Plutonium Reclamation Facility acid (approx. 2M HNO/sub 3/) waste stream (CAW solution) was studied. A solvent extraction process which employs a 30% DHDECMP (dihexyl-N, N-diethylcarbamylmethylene phosphonate)-CCl/sub 4/ extractant was devised and successfully tested in mixer-settler runs with actual CAW solution. Substitution of DHDECMP for DBBP eliminates the need to perform careful neutralization of unbuffered CAW soluton and increases overall americium recovery from the present 60 to 80% level to greater than or equal to 90%. Disadvantages to such substitution include the high cost (approx. $50/liter) of DHDECMP and the need to purify it (by acid (6M HCl) hydrolysis and alkaline washing) from small amounts of an unidentified impurity which prevents stripping of americium with dilute HNO/sub 3/. Distribution data obtained in this study confirm Siddall's earlier contention that bidentate organophosphorus regents can be used to remove actinides from concentrated high-level Purex process acid waste; a conceptual flowsheet for such an extraction process is given.

  20. Selective recovery of americium alone from PUREX or COEXTM raffinate by the EXAm process

    International Nuclear Information System (INIS)

    Americium is the main contributor to the long-term radiotoxicity and to the heat generation of glasses used for the HLW conditioning. To decrease both impact on the ultimate waste and to avoid the difficult recycling of curium, the CEA has developed the EXAm process for the the separation and the recovery of the sole americium directly from PUREX or COEXTM raffinates. The principle of the EXAm process is to extract americium and light lanthanides from high nitric acid media, leaving curium and heavy lanthanides in the raffinate. A water-soluble amide molecule, TEDGA, is added in aqueous phase to increase Am/Cm and Am/heavy lanthanides selectivity, because of the preferential complexation of curium and heavy lanthanides by this diglycolamide. Many experimental data have been acquired mainly at the extraction-scrubbing step (Am/Cm separation) and were used for the development of a phenomenological model implemented in the PAREX process simulation code. The scientific feasibility demonstration of the EXAm process was then performed on a genuine PUREX raffinate in Atalante CBP hot cell in 2010. (author)

  1. Uptake and effects of americium-241 on a brackish-water amphipod

    International Nuclear Information System (INIS)

    The present paper reports the results of experimental work undertaken using the brackish-water amphipod Gammarus duebeni duebeni and the transuranium nuclide americium-241. Data on the accumulation of this actinide showed that the larger fraction of the total body burden is associated with the exoskeleton. It was found that the body burden remained constant in the range pH 8.0-6.5 even though the water concentration changed markedly. It would thus appear that the concept of a concentration factor should be re-examined and it is proposed that a factor should be defined in terms of environmental and chemical parameters which represent the bioavailable fraction of the actinide. The effect of americium on survival and moulting was studied at two activity concentrations; the dose rates and absorbed doses under the experimental conditions employed have been estimated. The differences in survival rates between the control and irradiated groups were statistically analyzed and the significant difference at the higher concentration is believed to be due to a synergism between physiological stress and radiotoxicity of americium rather than the chemical toxicity of the element. (orig.)

  2. About the reaction between uranium-americium mixed oxides and sodium

    International Nuclear Information System (INIS)

    The recycling and fission of the highly toxic minor actinides neptunium and americium is only possible in a liquid metal cooled fast breeder reactor, for nuclear physical reasons. The present work is part of a research program dealing with the fuel-coolant interaction. Fuel pellets with equal parts of americium and uranium and varying oxygen-metal ratio were investigated. A behaviour comparable to that of uranium-plutonium mixed oxides was suggested as a first approach. The reaction of sodium with (U0.5Am0.5)O2-x results in a complete desintegration of the sintered pellet whereas (U, Pu)O2-x pellets show a small increase in volume. A first explanation of the strong reaction of uranium-americium mixed oxides compared to (U, Pu)O2-x or (U, Np)O2-x could be provided by the less negative oxygen potential of the former. Ternary and polynary oxides which are possible products of the fuel-coolant reaction were prepared and characterised by X-ray diffraction. Their oxygen potentials were measured using a solid state e.m.f. cell. Neither Na2AmO3 nor Na3AmO4 can coexist with sodium metal. The measured ΔGO2 values of the Am(IV) and Am (V)-compounds are much higher than those of the sodium uranates(VI) or sodium neptunates(VI). Only Na2O seems to be likely as product of the fuel-coolant interactions. It could be determined in reacted samples by X-ray diffraction. The relatively high oxygen potentials of (U0.5Am0.5)O2-x that are responsible for the reaction could be explained by a binding model which is based on an americium valency state of + 3 and U5+. The existence of both valency states could be proved by XPS measurements. Due to the similar behaviour of neptunium and uranium the problems that are expected for the recycling of Np are much smaller than for americium

  3. Americium(3) coordination chemistry: An unexplored diversity of structure and bonding

    Energy Technology Data Exchange (ETDEWEB)

    Fedosseev, A.M.; Grigoriev, M.S.; Budantseva, N.A. [A.N. Frumkin Institute of Physical Chemistry and Electrochemistry, Moscow (Russian Federation); Guillaumont, D.; Den Auwer, Ch.; Moisy, Ph. [CEA Marcoule, Nuclear Energy Division, RadioChemistry and Processes Department, 30 (France); Le Naour, C.; Simoni, E. [CNRS, University Paris-11 Orsay, IPN, 91 - Orsay (France)

    2010-06-15

    The comparison of the physicochemical behavior of the actinides with that of the lanthanides can be justified by the analogy of their electronic structure, as each of the series is made up of elements corresponding to the filling of a given (n)f atomic shell. However relatively few points of comparison are available, given the lack of available structure for trans-plutonium(III) elements and the additional difficulty of stabilizing coordination complexes of uranium(III) to plutonium(III). This contribution is a focal point of trans-plutonium(III) chemistry and, more specifically, of some americium compounds that have been recently synthesized, all related with hard acid oxygen donor ligands that may be involved in the reprocessing chain of nuclear fuel. After a brief review of the solid hydrates and aquo species for the lanthanide and actinide families, we discuss two types of ligands that have in common three carboxylic groups, namely the amino-tri-acetic acid and the citric acid anions. The additional roles of the nitrogen atom for the first one and of the hydroxy function for the second one are discussed. Accordingly, five new complexes with either americium or lanthanides elements are described: [Co(NH{sub 3}){sub 6}][M(NTA){sub 2}(H{sub 2}O)].8H{sub 2}O with M Nd, Yb and Am, and [Co(NH{sub 3}){sub 6}]{sub 2}K[M{sub 3}(Cit){sub 4}(H{sub 2}O){sub 3}].18H{sub 2}O with Nd and Am cations. In all cases the americium complexes are isostructural with their lanthanide equivalents. (authors)

  4. Americium(3) coordination chemistry: An unexplored diversity of structure and bonding

    International Nuclear Information System (INIS)

    The comparison of the physicochemical behavior of the actinides with that of the lanthanides can be justified by the analogy of their electronic structure, as each of the series is made up of elements corresponding to the filling of a given (n)f atomic shell. However relatively few points of comparison are available, given the lack of available structure for trans-plutonium(III) elements and the additional difficulty of stabilizing coordination complexes of uranium(III) to plutonium(III). This contribution is a focal point of trans-plutonium(III) chemistry and, more specifically, of some americium compounds that have been recently synthesized, all related with hard acid oxygen donor ligands that may be involved in the reprocessing chain of nuclear fuel. After a brief review of the solid hydrates and aquo species for the lanthanide and actinide families, we discuss two types of ligands that have in common three carboxylic groups, namely the amino-tri-acetic acid and the citric acid anions. The additional roles of the nitrogen atom for the first one and of the hydroxy function for the second one are discussed. Accordingly, five new complexes with either americium or lanthanides elements are described: [Co(NH3)6][M(NTA)2(H2O)].8H2O with M Nd, Yb and Am, and [Co(NH3)6]2K[M3(Cit)4(H2O)3].18H2O with Nd and Am cations. In all cases the americium complexes are isostructural with their lanthanide equivalents. (authors)

  5. Speciation of americium in seawater and accumulation in the marine sponge Aplysina cavernicola.

    Science.gov (United States)

    Maloubier, Melody; Michel, Hervé; Solari, Pier Lorenzo; Moisy, Philippe; Tribalat, Marie-Aude; Oberhaensli, François R; Dechraoui Bottein, Marie Yasmine; Thomas, Olivier P; Monfort, Marguerite; Moulin, Christophe; Den Auwer, Christophe

    2015-12-21

    The fate of radionuclides in the environment is a cause of great concern for modern society, seen especially in 2011 after the Fukushima accident. Among the environmental compartments, seawater covers most of the earth's surface and may be directly or indirectly impacted. The interaction between radionuclides and the marine compartment is therefore essential for better understanding the transfer mechanisms from the hydrosphere to the biosphere. This information allows for the evaluation of the impact on humans via our interaction with the biotope that has been largely undocumented up to now. In this report, we attempt to make a link between the speciation of heavy elements in natural seawater and their uptake by a model marine organism. More specifically, because the interaction of actinides with marine invertebrates has been poorly studied, the accumulation in a representative member of the Mediterranean coralligenous habitat, the sponge Aplysina cavernicola, was investigated and its uptake curve exposed to a radiotracer (241)Am was estimated using a high-purity Ge gamma spectrometer. But in order to go beyond the phenomenological accumulation rate, the speciation of americium(III) in seawater must be assessed. The speciation of (241)Am (and natural europium as its chemically stable surrogate) in seawater was determined using a combination of different techniques: Time-Resolved Laser-Induced Fluorescence (TRLIF), Extended X-ray Absorption Fine Structure (EXAFS) at the LIII edge, Attenuated Total Reflectance Fourier Transform Infrared (ATR-FTIR) spectroscopy and Scanning Electron Microscopy (SEM) and the resulting data were compared with the speciation modeling. In seawater, the americium(III) complex (as well as the corresponding europium complex, although with conformational differences) was identified as a ternary sodium biscarbonato complex, whose formula can be tentatively written as NaAm(CO3)2·nH2O. It is therefore this chemical form of americium that is

  6. Fabrication of uranium–americium mixed oxide pellet from microsphere precursors: Application of CRMP process

    Energy Technology Data Exchange (ETDEWEB)

    Remy, E. [Radiochemistry and Processes Department, CEA, Nuclear Energy Division, F-30207 Bagnols-sur-Cèze (France); Picart, S., E-mail: sebastien.picart@cea.fr [Radiochemistry and Processes Department, CEA, Nuclear Energy Division, F-30207 Bagnols-sur-Cèze (France); Delahaye, T. [Fuel Cycle Technology Department, CEA, Nuclear Energy Division, F-30207 Bagnols-sur-Cèze (France); Jobelin, I. [Radiochemistry and Processes Department, CEA, Nuclear Energy Division, F-30207 Bagnols-sur-Cèze (France); Lebreton, F.; Horlait, D. [Fuel Cycle Technology Department, CEA, Nuclear Energy Division, F-30207 Bagnols-sur-Cèze (France); Bisel, I. [Radiochemistry and Processes Department, CEA, Nuclear Energy Division, F-30207 Bagnols-sur-Cèze (France); Blanchart, P. [Heterogeneous Materials Research Group, Centre Européen de la Céramique, F-87068 Limoges (France); Ayral, A. [Institut Européen des Membranes, CNRS-ENSCM-UM2, CC47, University Montpellier 2, F-34095 Montpellier cedex 5 (France)

    2014-10-15

    Highlights: • Dust free process for (U,Am)O{sub 2} transmutation target fabrication. • Synthesis of U{sub 0.9}Am{sub 0.1}O{sub 2} mixed oxide microspheres from ion exchange resin. • Fabrication of dense U{sub 0.9}Am{sub 0.1}O{sub 2} pellet with 95% TD from mixed oxide microspheres. - Abstract: Mixed uranium–americium oxides are one of the materials envisaged for Americium Bearing Blankets dedicated to transmutation in fast neutron reactors. Recently, several processes have been developed in order to validate fabrication flowchart in terms of material specifications such as density and homogeneity but also to suggest simplifications for lowering industrial costs and hazards linked to dust generation of highly contaminating and irradiating compounds. This study deals with the application of an innovative route using mixed oxide microspheres obtained from metal loaded resin bead calcination, called Calcined Resin Microsphere Pelletization (CRMP). The synthesis of mixed oxide microsphere precursor of U{sub 0.9}Am{sub 0.1}O{sub 2±δ} is described as well as its characterisation. The use of this free-flowing precursor allows the pressing and sintering of one pellet of U{sub 0.9}Am{sub 0.1}O{sub 2±δ}. The ceramic obtained was characterised and results showed that its microstructure is dense and homogeneous and its density attains 95% of the theoretical density. This study validates the scientific feasibility of the CRMP process applied to the fabrication of uranium and americium-containing materials.

  7. Americium characterization by X-ray fluorescence and absorption spectroscopy in plutonium uranium mixed oxide

    International Nuclear Information System (INIS)

    Plutonium uranium mixed oxide (MOX) fuels are currently used in nuclear reactors. The actinides in these fuels need to be analyzed after irradiation for assessing their behaviour with regard to their environment and the coolant. In this work the study of the atomic structure and next-neighbour environment of Am in the (Pu,U)O2 lattice in an irradiated (60 MW d kg−1) MOX sample was performed employing micro-X-ray fluorescence (µ-XRF) and micro-X-ray absorption fine structure (µ-XAFS) spectroscopy. The chemical bonds, valences and stoichiometry of Am (∼0.66 wt%) are determined from the experimental data gained for the irradiated fuel material examined in its peripheral zone (rim) of the fuel. In the irradiated sample Am builds up as Am3+ species within an [AmO8]13− coordination environment (e.g. >90%) and no (III XAFS spectra recorded for the irradiated MOX sub-sample in the rim zone for a 300 μm×300 μm beam size area investigated over six scans of 4 h. The records remain constant during multi-scan. The analysis of the XAFS signal shows that Am is found as trivalent in the UO2 matrix. This analytical work shall open the door of very challenging analysis (speciation of fission product and actinides) in irradiated nuclear fuels. - Highlights: • Americium was characterized by microX-ray absorption spectroscopy in irradiated MOX fuel. • The americium redox state as determined from XAS data of irradiated fuel material was Am(III). • In the sample, the Am3+ face an AmO813− coordination environment in the (Pu,U)O2 matrix. • The americium dioxide is reduced by the uranium dioxide matrix

  8. Recovery of Americium-241 from lightning rod by the method of chemical treatment

    International Nuclear Information System (INIS)

    About 95% of the lightning rods installed in the Peruvian territory have set in their structures, pose small amounts of radioactive sources such as Americium-241 (241Am), fewer and Radium 226 (226Ra) these are alpha emitters and have a half life of 432 years and 1600 years respectively. In this paper describes the recovery of radioactive sources of 241Am radioactive lightning rods using the conventional chemical treatment method using agents and acids to break down the slides. The 241Am recovered was as excitation source and alpha particle generator for analysing samples by X Ray Fluorescence, for fixing the stainless steel 241Am technique was used electrodeposition. (author)

  9. Report of scouting study on precipitation of strontium, plutonium, and americium from Hanford complexant concentrate waste

    International Nuclear Information System (INIS)

    A laboratory scouting test was conducted of precipitation methods for reducing the solubility of radionuclides in complexant concentrate (CC) waste solution. The results show that addition of strontium nitrate solution is effective in reducing the liquid phase activity of 90Sr (Strontium) in CC waste from tank 107-AN by 94% when the total strontium concentration is adjusted to 0.1 M. Addition of ferric nitrate solution effective in reducing the 241Am (Americium) activity in CC waste by 96% under the conditions described in the report. Ferric nitrate was also marginally effective in reducing the solubility of 239/240Pu (Plutonium) in CC waste

  10. Plutonium and americium in arctic waters, the North Sea and Scottish and Irish coastal zones

    DEFF Research Database (Denmark)

    Hallstadius, L.; Aarkrog, Asker; Dahlgaard, Henning;

    1986-01-01

    Plutonium and americium have been measured in surface waters of the Greenland and Barents Seas and in the northern North Sea from 1980 through 1984. Measurements in water and biota, Fucus, Mytilus and Patella, were carried out in North-English and Scottish waters in 1982 and Fucus samples were...... plutonium from the latter to Spitsbergen waters. Fallout plutonium in Arctic waters has a residence time of the order of several years, while for Pu from Sellafield we estimate mean residence times of 11–15 months in Scottish waters and, tentatively, 1·5-3 y during transport from the North Channel (north...

  11. Americium and curium heterogeneous transmutation in moderated S/ A in the framework of CNE scenarios studies

    International Nuclear Information System (INIS)

    This paper presents the transmutation of Americium and Curium in a heterogeneous mode in the framework of the 1991 French Law concerning waste management. Two scenarios with moderated targets are presented: a 100% frit reactor (EFR) scenario multi-recycling Pu+Np with targets of Am+Cm placed in core and a mixed PWR (UOX fuel) and fast reactor (50% of EFR) multi-recycling Pu+Np and containing targets in core and in the blanket region. The design of the target is based on classical fast fuel S/A technology (pins, spacer wires,...) and should reach the goal of 90% fission rate. (authors)

  12. Laboratory investigation of the role of desorption kinetics on americium transport associated with bentonite colloids.

    Science.gov (United States)

    Dittrich, Timothy Mark; Boukhalfa, Hakim; Ware, Stuart Douglas; Reimus, Paul William

    2015-10-01

    Understanding the parameters that control colloid-mediated transport of radionuclides is important for the safe disposal of used nuclear fuel. We report an experimental and reactive transport modeling examination of americium transport in a groundwater-bentonite-fracture fill material system. A series of batch sorption and column transport experiments were conducted to determine the role of desorption kinetics from bentonite colloids in the transport of americium through fracture materials. We used fracture fill material from a shear zone in altered granodiorite collected from the Grimsel Test Site (GTS) in Switzerland and colloidal suspensions generated from FEBEX bentonite, a potential repository backfill material. The colloidal suspension (100 mg L(-1)) was prepared in synthetic groundwater that matched the natural water chemistry at GTS and was spiked with 5.5 × 10(-10) M (241)Am. Batch characterizations indicated that 97% of the americium in the stock suspension was adsorbed to the colloids. Breakthrough experiments conducted by injecting the americium colloidal suspension through three identical columns in series, each with mean residence times of 6 h, show that more than 95% of the bentonite colloids were transported through each of the columns, with modeled colloid filtration rates (k(f)) of 0.01-0.02 h(-1). Am recoveries in each column were 55-60%, and Am desorption rate constants from the colloids, determined from 1-D transport modeling, were 0.96, 0.98, and 0.91 h(-1) in the three columns, respectively. The consistency in Am recoveries and desorption rate constants in each column indicates that the Am was not associated with binding sites of widely-varying strengths on the colloids, as one binding site with fast kinetics represented the system accurately for all three sequential columns. Our data suggest that colloid-mediated transport of Am in a bentonite-fracture fill material system is unlikely to result in transport over long distance scales because

  13. Purification of used scintillation liquids containing the alpha emitters americium and plutonium

    International Nuclear Information System (INIS)

    In Sweden, alpha radioactive waste liquids with an activity over some kBq per waste container cannot be sent for final storage. Therefore, in this work, a method for a purification of alpha active scintillation cocktails was developed. Until today (March, 2013) more than 20 L of scintillation liquids have successfully been purified from americium and plutonium. The products of the process are a solid fraction that can be sent to final storage and a practically non-radioactive liquid fraction that can be sent to municipal incineration. (author)

  14. Comparison of acid leachate and fusion methods to determine plutonium and americium in environmental samples

    International Nuclear Information System (INIS)

    The Analytical Chemistry Laboratory at Argonne National Laboratory performs radiochemical analyses for a wide variety of sites within the Department of Energy complex. Since the chemical history of the samples may vary drastically from site to site, the effectiveness of any analytical technique may also vary. This study compares a potassium fluoride-pyrosulfate fusion technique with an acid leachate method. Both normal and high-fired soils and vegetation samples were analyzed for both americium and plutonium. Results show both methods work well, except for plutonium in high-fired soils. Here the fusion method provides higher accuracy

  15. Plutonium and americium in arctic waters, the North Sea and Scottish and Irish coastal zones

    DEFF Research Database (Denmark)

    Hallstadius, L.; Aarkrog, Asker; Dahlgaard, Henning; Holm, E.; Boelskifte, S.; Duniec, S.; Persson, B.

    1986-01-01

    Plutonium and americium have been measured in surface waters of the Greenland and Barents Seas and in the northern North Sea from 1980 through 1984. Measurements in water and biota, Fucus, Mytilus and Patella, were carried out in North-English and Scottish waters in 1982 and Fucus samples were...... plutonium from the latter to Spitsbergen waters. Fallout plutonium in Arctic waters has a residence time of the order of several years, while for Pu from Sellafield we estimate mean residence times of 11–15 months in Scottish waters and, tentatively, 1·5-3 y during transport from the North Channel (north of...

  16. Influence of biofilms on migration of uranium, americium and europium in the environment

    International Nuclear Information System (INIS)

    The report on the influence of biofilms on migration of uranium, americium and europium in the environment deals with the contamination problems of uranium mines such as SDAG WISMUT in Saxonia and Thuringia. In mine waters microorganisms form a complex microbiological biocoenosis in spite of low pH values and high heavy metal concentrations including high uranium concentrations. The analyses used microbiological methods like confocal laser scanning microscopy and molecular-biological techniques. The interactions of microorganism with fluorescent radioactive heavy metal ions were performed with TRLFS (time resolved laser-induced fluorescence spectroscopy).

  17. Numerical simulation for concentration profiles of americium and lanthanides in the CMPO-TBP solvent extraction system

    International Nuclear Information System (INIS)

    A numerical simulation code is developed to predict the extraction behavior of americium and lanthanides in the TRUEX (TRansUranium EXtraction)process. This code gives the concentration profiles of the components at steady state. The stage efficiency is included in this code as a parameter in order to simulate the extraction behavior of the components accurately. Concentration profiles of americium and typical lanthanides in some counter current experiments are calculated by means of the present code. The calculated concentration profiles are compared with the experimental results. The efficiency value for the mixer-settlers, which gives good agreement between the calculated and the experimental profiles, is evaluated. (author)

  18. Numerical simulation for concentration profiles of americium and lanthanides in the CMPO-TBP solvent extraction system

    International Nuclear Information System (INIS)

    A numerical simulation code for the TRUEX (TRansUranium EXtraction) process is developed to predict the extraction behavior of americium and lanthanides. This code gives the concentrations of the components at the steady state of the TRUEX process. The stage efficiency is applied to this code in order to simulate the extraction behavior of the components accurately. Concentration profiles of americium and typical lanthanides in some counter current experiments are calculated by means of the present code. The calculated profiles are compared with the experimental ones. The efficiency value for the mixer-settlers, which gives the best agreement between the two profiles, is investigated

  19. Study of the extraction and the purification of americium and trivalent actinides contained in effluents with supported liquid membranes

    International Nuclear Information System (INIS)

    The supported liquid membrane technique is studied and developed for americium recovery from uranium or plutonium matrices and decontamination of liquid radioactive wastes. First tests on uranium-nickel solutions with a flat membrane showed the easiness of the operation and the efficiency of the process. Acid-resistant (10 N), interchangeable elements with hollow fibers, are developed and also a computerized automatic device. The different tests on americium solutions demonstrate the feasibility and the reliability of the system. Influence of various parameters on transfer kinetics is investigated

  20. Experimental and in situ investigations on americium, curium and plutonium behaviour in marine benthic species: transfer from water or sediments

    International Nuclear Information System (INIS)

    The tranfer of transuranic elements -americium, curium and plutonium- from the sediments containing them to some marine benthic species (endofauna and epifauna) was studied with a twofold approach - laboratory and in-situ investigation. The experimental investigations, divided into three parts, made it possible to specify concentration factors (F.C.), transfer factors (F.T.) and to understand the process involved for 5 benthic species. The result were refined by an in-situ study that brought new data on the marine distribution of the transuranic elements released by the La Hague plant. Finally, the localization of americium and plutonium in the tissues and cells of these species was determined by autoradiography

  1. Vitrification of F-area americium/curium: feasibility study and preliminary process recommendation

    International Nuclear Information System (INIS)

    Work was performed to identify a process to vitrify the contents of F- canyon Tank 17.1. Tank 17.1 contains the majority of americium (Am) and curium (Cm) contained in the DOE Complex. Oak Ridge National Laboratory (ORNL) has made a formal request for this material as fuel for production of Cf252 and other transplutonium actinides. The Am and Cm (and associated lanthanide fission products) are currently in nitric acid solution. Transportation of the intensely radioactive Am/Cm in liquid form is not considered possible. As a result, the material will either be solidified and shipped to ORNL or discarded to the Tank Farm. Nuclear Materials Processing Technology (NMPT), therefore, requested Defense Waste Processing Technology (DWPT) to determine if the Tank 17.1 material could be vitrified, and if it was vitrified could the americium and curium be successfully recovered. Research was performed to determine if the Tank 17.1 contents could indeed be mixed with glass formers and vitrified. Additional studies identified critical process parameters such as heat loading, melter requirements, off-gas evolution, etc. Discussions with NMPT personnel were initiated to determine existing facilities where this work could be accomplished safely. A process has been identified which will convert the Am/Cm material into approximately 300kg of glass

  2. Transfer of radiocaesium, plutonium and americium to sheep after ingestion of contaminated soil

    International Nuclear Information System (INIS)

    A dual isotope method has been used to study the transfer of 137Cs, 239/240Pu and 241Am to sheep following ingestion of contaminated soil. Two soils were used; an alluvial gley contaminated by Sellafield discharges, and an organic soil, artificially contaminated in a lysimeter. Values of the true absorption coefficient of radiocaesium of 0.19 +/- 0.03 and 0.03 +/- 0.01 respectively were obtained for these soils. This implies an availability factor for soil-associated radiocaesium of up to about 20 pc compared to radiocaesium ingested in soluble form. The absorption of plutonium and americium was not significantly different for the two soils tested. Absorption of both plutonium and americium was in the range 10-5 - 10-4, with mean values of 7 x 10-5 and 4 x 10-5 obtained respectively. These values imply availability factors of around 10 pc, compared to the value of 5 x 10-4 recommended by ICRP for plutonium ingested in a comparatively available form. These results are compared with estimates of availability made using an in-vitro approach

  3. Transfer of radiocaesium, plutonium and americium to sheep after ingestion of contaminated soil

    Energy Technology Data Exchange (ETDEWEB)

    Cooke, A.I.; Weekes, T.E.C. [Newcastle upon Tyne Univ. (United Kingdom). Dept. of Biological and Nutritional Sciences; Rimmer, D.L. [Newcastle upon Tyne Univ. (United Kingdom). Dept. of Agricultural and Environmental Science; Green, N.; Wilkins, B.T. [National Radiological Protection Board, Chilton (United Kingdom)

    1997-12-31

    A dual isotope method has been used to study the transfer of {sup 137}Cs, {sup 239/240}Pu and {sup 241}Am to sheep following ingestion of contaminated soil. Two soils were used; an alluvial gley contaminated by Sellafield discharges, and an organic soil, artificially contaminated in a lysimeter. Values of the true absorption coefficient of radiocaesium of 0.19 +/- 0.03 and 0.03 +/- 0.01 respectively were obtained for these soils. This implies an availability factor for soil-associated radiocaesium of up to about 20 pc compared to radiocaesium ingested in soluble form. The absorption of plutonium and americium was not significantly different for the two soils tested. Absorption of both plutonium and americium was in the range 10{sup -5} - 10{sup -4}, with mean values of 7 x 10{sup -5} and 4 x 10{sup -5} obtained respectively. These values imply availability factors of around 10 pc, compared to the value of 5 x 10{sup -4} recommended by ICRP for plutonium ingested in a comparatively available form. These results are compared with estimates of availability made using an in-vitro approach

  4. Americium and europium extraction from carbonate solutions by 1-phenyl-3-methyl-4-benzoylpyrazolone -5

    International Nuclear Information System (INIS)

    Trivalent TPEs and REEs are extractable from carbonate solutions by 1-pheny-3-methyl-4-benzoylpyrazolone-5 (PMBP). The effect of concentration of KHCO3 and K2CO3, extractant, metal, and other factors on the extent of extraction of the elements has been clarified. The kinetics of extraction of the elements from carbonate solutions has been studied. It has been shown that in the KHCO3 concentration range 0.2-2.0 M americium and europium are extracted by PMBP solutions in different diluents with distribution coefficients lying within n x 102-n x 103. From K2CO3 solutions the elements are extracted better by PMBP solutions in methyl isobutyl ketone (MIBK). It has been shown that metal concentration in the range 1x10-5. 5x10-3 g-ion x liter-1 does not affect extraction (log E = 3). Extracts based on PMBP with a metal content higher than 5x10-3g-ion x liter-1 were obtained by absolute concentrating method and were used for the study of 13C NMR spectra. The composition of thecompounds extracted by PMBP from carbonate solutions was determined by 13C NMR spectroscopy and extraction. The conditions of europium and americium reextraction from extracts based on PMBP by complexones, their mixtures with alkalis and other substances were studied. The scopes for using the system PMBP-carbonate solutions to separate and concentrate TPEs and REEs has been examined

  5. Evaluation of americium-241 toxicity influence on the microbial growth of organic wastes

    International Nuclear Information System (INIS)

    Available in abstract form only. Full text of publication follows: Since the licenses for using radioactive sources in radioactive lightning rods were lifted by the Brazilian national nuclear authority, in 1989, the radioactive devices have been replaced by Franklin type and collected as radioactive waste. However, only 20 percent of the estimated total number of installed rods was delivered to Brazilian Nuclear Commission. This situation causes concern, due to, first, the possibility of the rods being disposed as domestic waste, and second, the americium, the most commonly employed radionuclide, is classified as a high-toxicity element. In the present study, Am-241 migration experiments were performed by a lysimeter system, in order to evaluate the risk of contamination caused by radioactive lightning rods disposed as a common solid waste. Besides the risk evaluation, it is important to know the mechanism of the Am-241 release or retention in waste as well as its influence in the waste decomposition processes. Many factors are involved, but microorganisms present in the waste play an important role in its degradation, which control the physical and chemical processes. The objective of this work was to evaluate the Am-241 influence on the microbial population by counting number of cells in lysimeters leachate. Preliminary results suggest that americium may influence significantly the bacteria growth in organic waste, evidenced by culture under aerobiosis and an-aerobiosis and the antimicrobial resistance test. (authors)

  6. Contribution to the prediction of americium, plutonium and neptunium behaviour in the geosphere: chemical data

    International Nuclear Information System (INIS)

    An exhaustive bibliographic review on hydrolysis of americium gives the stability constants, at zero ionic strength. No evidence of Am(OH)4- formation was found by solubility studies up to pH 2 (CO3)3 characterised by its X-ray diffraction pattern is studied at a high ionic strength. All the published results on Am in carbonate media are reinterpreted using these stability constants (Am-OH-CO3 complexes are not needed). No evidence of Am(CO3)45- formation was found by spectrophotometry up to 3M. Literature results are used to determine the formal redox potentials at pH = 9.4 and to calculate the formation constants, at zero ionic strength. The formation of complexes between americium and humic materials (purified fulvic and humic acids) has been studied by a spectrophotometric technique. The results are interpreted by the formation of a 1:1 complexe. Solubility of the solid PuO2(CO3) is measured in bicarbonate media at high ionic strength, to obtain the solubility product and formation constants of the PuO2(CO3)i2-2i complexes

  7. EURADOS intercomparison on measurements and Monte Carlo modelling for the assessment of Americium in a USTUR leg phantom

    International Nuclear Information System (INIS)

    A collaboration of the EURADOS working group on 'Internal Dosimetry' and the United States Transuranium and Uranium Registries (USTUR) has taken place to carry out an intercomparison on measurements and Monte Carlo modelling determining americium deposited in the bone of a USTUR leg phantom. Preliminary results and conclusions of this intercomparison exercise are presented here. (authors)

  8. An economic analysis of a light and heavy water moderated reactor synergy: burning americium using recycled uranium

    International Nuclear Information System (INIS)

    An economic analysis is presented for a proposed synergistic system between 2 nuclear utilities, one operating light water reactors (LWR) and another running a fleet of heavy water moderated reactors (HWR). Americium is partitioned from LWR spent nuclear fuel (SNF) to be transmuted in HWRs, with a consequent averted disposal cost to the LWR operator. In return, reprocessed uranium (RU) is supplied to the HWRs in sufficient quantities to support their operation both as power generators and americium burners. Two simplifying assumptions have been made. First, the economic value of RU is a linear function of the cost of fresh natural uranium (NU), and secondly, plutonium recycling for a third utility running a mixed oxide (MOX) fuelled reactor fleet has been already taking place, so that the extra cost of americium recycling is manageable. We conclude that, in order for this scenario to be economically attractive to the LWR operator, the averted disposal cost due to partitioning americium from LWR spent fuel must exceed 214 dollars per kg, comparable to estimates of the permanent disposal cost of the high level waste (HLW) from reprocessing spent LWR fuel. (authors)

  9. Effects of Hanford high-level waste components on sorption of cobalt, strontium, neptunium, plutonium, and americium on Hanford sediments

    Energy Technology Data Exchange (ETDEWEB)

    Delegard, C H; Barney, G S

    1983-03-01

    To judge the feasibility of continued storage of high-level waste solutions in existing tanks, effects of chemical waste components on the sorption of hazardous radioelements were determined. Experiments identified the effects of 12 Hanford high-level waste-solution components on the sorption of cobalt, strontium, neptunium, plutonium, and americium on 3 Hanford 200 Area sediments. The degree of sorption of strontium, neptunium, plutonium, and americium on two Hanford sediments was then quantified in terms of the concentrations of the influential waste components. Preliminary information on the influence of the waste components on radioelement solubility was gathered. Of the 12 Hanford waste-solution components studied, the most influential on radioelement sorption were NaOH, NaAlO/sub 2/, HEDTA, and EDTA. The chelating complexants, HEDTA and EDTA, generally decreased sorption by complexation of the radioelement metal ions. The components NaOH and NaAlO/sub 2/ decreased neptunium and plutonium sorption and increased cobalt sorption. Americium sorption was increased by NaOH. The three Hanford sediments' radioelement sorption behaviors were similar, implying that their sorption reactions were also similar. Sorption prediction equations were generated for strontium, neptunium, plutonium, and americium sorption reactions on two Hanford sediments. The equations yielded values of the distribution coefficient, K/sub d/, as quadratic functions of waste-component concentrations and showed that postulated radioelement migration rates through Hanford sediment could change by factors of 13 to 40 by changes in Hanford waste composition.

  10. Effects of Hanford high-level waste components on sorption of cobalt, strontium, neptunium, plutonium, and americium on Hanford sediments

    International Nuclear Information System (INIS)

    To judge the feasibility of continued storage of high-level waste solutions in existing tanks, effects of chemical waste components on the sorption of hazardous radioelements were determined. Experiments identified the effects of 12 Hanford high-level waste-solution components on the sorption of cobalt, strontium, neptunium, plutonium, and americium on 3 Hanford 200 Area sediments. The degree of sorption of strontium, neptunium, plutonium, and americium on two Hanford sediments was then quantified in terms of the concentrations of the influential waste components. Preliminary information on the influence of the waste components on radioelement solubility was gathered. Of the 12 Hanford waste-solution components studied, the most influential on radioelement sorption were NaOH, NaAlO2, HEDTA, and EDTA. The chelating complexants, HEDTA and EDTA, generally decreased sorption by complexation of the radioelement metal ions. The components NaOH and NaAlO2 decreased neptunium and plutonium sorption and increased cobalt sorption. Americium sorption was increased by NaOH. The three Hanford sediments' radioelement sorption behaviors were similar, implying that their sorption reactions were also similar. Sorption prediction equations were generated for strontium, neptunium, plutonium, and americium sorption reactions on two Hanford sediments. The equations yielded values of the distribution coefficient, K/sub d/, as quadratic functions of waste-component concentrations and showed that postulated radioelement migration rates through Hanford sediment could change by factors of 13 to 40 by changes in Hanford waste composition

  11. Anomalous aryl strengthening of americium and europium complexes during extraction by alkylenediphosphine dioxides from perchloric acid media

    International Nuclear Information System (INIS)

    Extraction of americium and europium from perchlorate environments by solutions of three types of methylenediphosphine dioxides, namely (C6H5)P(O)(CH2)sub(n)(O)P(C6H5)2, (C6H5)2P(O)CH2(O)P(C8H17)2 and (C8H17)2P(O)(CH2)sub(n)(O)P(C8H17)2 has been studied (n is 1 or 2 ) The diluents used have been dichlorethane and chloroform. In perchlorate environments the distribuiton coefficients of americium and europium have proved to be by about 3 orders of magnitude higher than in nitric acid environments, i.e. in perchlorate media the complexes are far more stable. Separation coefficients of americium and REE in perchloric acid soutions are much higher than in nitrate environments. The average value of Am/Eu separation coeffecient at 1-5 M acidity was about 6 (with dichlorethane as diluent) or about 7 (with chloroform as diluent). The complexes essentially exist as trisolvated. Americium complexes display anomalous stability increase upon being diluted: by about 2 orders of magnitude with dichlorethane and by up to 3 orders of magnitude with chloroform used as diluent

  12. Investigations of neutron characteristics for salt blanket models; integral fission cross section measurements of neptunium, plutonium, americium and curium isotopes

    International Nuclear Information System (INIS)

    Neutron characteristics of salt blanket micromodels containing eutectic mixtures of sodium, zirconium, and uranium fluorides were measured on FKBN-2M, BIGR and MAKET facilities. The effective fission cross sections of neptunium, plutonium, americium, and curium isotopes were measured on the neutron spectra formed by micromodels. (author)

  13. The distribution of plutonium-239 and americium-241 in the Syrian hamster following its intravenous administration as citrate

    International Nuclear Information System (INIS)

    Actinide distribution in various tissues and the skeleton of hamsters by liquid scintillation counting or isotope dilution. For plutonium 57% of activity was concentrated in the skeleton and more than 90% in the liver and skeleton after seven days. For americium the liver retained more than 50% of total activity and 25% was excreted in urine within seven days. (U.K.)

  14. Application of ion-exchange chromatography to eliminate the curium from americium by his determination by the method of liquid scintillation spectrometry

    International Nuclear Information System (INIS)

    The aim of this work is to eliminate curium in determining of americium by the method of liquid scintillation spectrometry. The paper introduces a method that has been done to eliminate curium from americium by determining of americium with liquid scintillation spectrometry method. In the research we used ion-exchange chromatography and ion-exchange sorbents DOWEX. We also observed the effect of geometry organization of column on the separation course. Resources for alpha spectrometry were prepared by micro-precipitation with neodymium chloride. High radiochemical yields were achieved, but separation did not take place according to a pre-separation scheme. (authors)

  15. Purification of scintillation cocktails containing the alpha emitters americium and plutonium

    International Nuclear Information System (INIS)

    One efficient way of measuring alpha emitters is by the usage of liquid scintillation counting (LSC). A liquid sample is placed in a vial containing a scintillation cocktail. The alpha particles excite electrons in the surrounding liquid, and when they are de-excited photons are emitted. The photons are detected and the activity can be quantified. LSC has a high efficiency for alpha radiation and is therefore a fast and easy way for measuring alpha emitting samples. One drawback is that it does not differentiate very well between alpha energies; measurements of for example curium and plutonium simultaneously are impossible and demand other techniques. Another drawback is the production of a liquid alpha active waste. In Sweden alpha radioactive waste liquids with an activity over some kBq per waste container cannot be sent for final storage. If, however, the activity of the liquids could be reduced by precipitation of the actinides, it would be possible to send away the liquid samples to municipal incineration. In this work a method for a purification of alpha active scintillation cocktails was developed. The method was first tried on a lab scale, and then scaled up. Until today (March, 2013) more than 20 liters of scintillation liquids have successfully been purified from americium and plutonium at Chalmers University of Technology in Sweden. The four scintillation cocktails used were Emulsifier Safe®, Hionic-Fluor®, Ultima Gold AB® and Ultima Gold XR®. The scintillation cocktails could all be purified from americium with higher yield than 95%. The yield was kept when the liquids were mixed. Also plutonium could be precipitated with a yield over 95% in all cocktails except in Hionic-Fluor® (>55%). However, that liquid in particular could be purified (>95%) by mixing it with the three other cocktails. Up-scaling was performed to a batch size of 6-8 L of scintillation cocktail. In neither the americium nor the plutonium system, adverse effects of increasing the

  16. Imitators of plutonium and americium in a mixed uranium- plutonium nitride fuel

    Science.gov (United States)

    Nikitin, S. N.; Shornikov, D. P.; Tarasov, B. A.; Baranov, V. G.; Burlakova, M. A.

    2016-04-01

    Uranium nitride and mix uranium nitride (U-Pu)N is most popular nuclear fuel for Russian Fast Breeder Reactor. The works in hot cells associated with the radiation exposure of personnel and methodological difficulties. To know the main physical-chemical properties of uranium-plutonium nitride it necessary research to hot cells. In this paper, based on an assessment of physicochemical and thermodynamic properties of selected simulators Pu and Am. Analogues of Pu is are Ce and Y, and analogues Am - Dy. The technique of obtaining a model nitride fuel based on lanthanides nitrides and UN. Hydrogenation-dehydrogenation- nitration method of derived powders nitrides uranium, cerium, yttrium and dysprosium, held their mixing, pressing and sintering, the samples obtained model nitride fuel with plutonium and americium imitation. According to the results of structural studies have shown that all the samples are solid solution nitrides rare earth (REE) elements in UN.

  17. Recovery of plutonium and americium from chloride salt wastes by solvent extraction

    International Nuclear Information System (INIS)

    Plutonium and americium can be recovered from aqueous waste solutions containing a mixture of HCl and chloride salt wastes by the coupling of two solvent extraction systems: tributyl phosphate (TBP) in tetrachloroethylene (TCE) and octyl(phenyl)-N,N-diisobutylcarbamoylmethylphosphine oxide (CMPO) in TCE. In the flowsheet developed, the salt wastes are dissolved in HCl, the Pu(III) is oxidized to the IV state with NaClO2 and recovered in the TBP-TCE cycle, and the Am is then removed from the resultant raffinate by the CMPO-TCE cycle. The consequences of the feed solution composition and extraction behavior of these species on the process flowsheet design, the Pu-product purity, and the decontamination of the aqueous raffinate from transuranic elements are discussed. 16 refs., 6 figs

  18. Recovery of plutonium and americium from chloride salt wastes by solvent extraction

    International Nuclear Information System (INIS)

    Plutonium and americium can be recovered from aqueous waste solutions containing a mixture of HCl and chloride salt wastes by the coupling of two solvent extraction systems: tributyl phosphate (TBP) in tetrachloroethylene (TCE) and octyl(phenyl)-N,N-diisobutyl-carbamoylmethylphosphine oxide (CMPO) in TCE. In the flowsheet developed, the salt wastes are dissolved in HCl, the Pu(III) is oxidized to the IV state with NaClO2 and recovered in the TBP-TCE cycle, and the Am is then removed from the resultant raffinate by the CMPO-TCE cycle. The consequences of the feed solution composition and extraction behavior of these species on the process flowsheet design, the Pu-product purity, and the decontamination of the aqueous raffinate from transuranic elements are discussed

  19. The uptake of plutonium-239, 240, americium-241, strontium-90 into plants

    International Nuclear Information System (INIS)

    This report describes the results of measurements on the uptake of plutonium, americium, strontium-90 and caesium-137 into peas, beet, oats, sweet corn, tomatoes and vegetable marrow grown in tubs containing radioactively-contaminated silts. The silts had been taken from an area of West Cumbria commonly referred to as the Ravenglass estuary. The experiments are categorised as being carried out under non-standard conditions because of the manner in which the radioactivity came to be incorporated into the growth medium. The growth medium was representative of conditions which could arise when the estuarine silt moves inland under the influence of wind and tide and mixes with the adjacent farm land. The silt had been contaminated by radioactive effluents from the nuclear fuels reprocessing plant at Sellafield and this contamination had been brought about by natural means. (Auth.)

  20. Mutual separation of americium(III) and europium(III) using glycolamic acid and thioglycolamic acid

    International Nuclear Information System (INIS)

    The extractants, bis(2-ethylhexyl)diglycolamicacid (HDEHDGA) and bis(2-ethylhexy)thiodiglycolamic acid (HDEHSDGA) were synthesized and characterized by 1H and 13C NMR, mass and IR spectroscopy. The extraction behaviour of (152+154)Eu(III) and 241Am(III) from nitric acid medium by a solution of HDEHDGA (or HDEHSDGA) in n-dodecane (n-DD) was studied for the mutual separation of actinides and lanthanides. The effect of various parameters such as the pH, concentrations of HDEHDGA, HDEHSDGA, sodium nitrate, N,N,N',N'-tetrakis(2-pyridylmethyl)ethylenediamine (TPEN) and diethylenetriaminepentaacetic acid (DTPA) on the separation factor (SF) of americium(III) over europium(III) and vice versa was studied, and the conditions needed for the preferential separation were optimised. The results show that HDEHDGA exhibits higher extraction for (152+154)Eu(III) and HDEHSDGA shows the superior selectivity for 241Am(III). (orig.)

  1. Laboratory investigation of the role of desorption kinetics on americium transport associated with bentonite colloids

    International Nuclear Information System (INIS)

    Understanding the parameters that control colloid-mediated transport of radionuclides is important for the safe disposal of used nuclear fuel. We report an experimental and reactive transport modeling examination of americium transport in a groundwater–bentonite–fracture fill material system. A series of batch sorption and column transport experiments were conducted to determine the role of desorption kinetics from bentonite colloids in the transport of americium through fracture materials. We used fracture fill material from a shear zone in altered granodiorite collected from the Grimsel Test Site (GTS) in Switzerland and colloidal suspensions generated from FEBEX bentonite, a potential repository backfill material. The colloidal suspension (100 mg L−1) was prepared in synthetic groundwater that matched the natural water chemistry at GTS and was spiked with 5.5 × 10−10 M 241Am. Batch characterizations indicated that 97% of the americium in the stock suspension was adsorbed to the colloids. Breakthrough experiments conducted by injecting the americium colloidal suspension through three identical columns in series, each with mean residence times of 6 h, show that more than 95% of the bentonite colloids were transported through each of the columns, with modeled colloid filtration rates (kf) of 0.01–0.02 h−1. Am recoveries in each column were 55–60%, and Am desorption rate constants from the colloids, determined from 1-D transport modeling, were 0.96, 0.98, and 0.91 h−1 in the three columns, respectively. The consistency in Am recoveries and desorption rate constants in each column indicates that the Am was not associated with binding sites of widely-varying strengths on the colloids, as one binding site with fast kinetics represented the system accurately for all three sequential columns. Our data suggest that colloid-mediated transport of Am in a bentonite-fracture fill material system is unlikely to result in transport over long distance

  2. Comparative study of plutonium and americium bioaccumulation from two marine sediments contaminated in the natural environment

    International Nuclear Information System (INIS)

    Plutonium and americium sediment-animal transfer was studied under controlled laboratory conditions by exposure of the benthic polychaete Nereis diversicolor (O. F. Mueller) to marine sediments contaminated by a nuclear bomb accident (near Thule, Greenland) and nuclear weapons testing (Enewetak Atoll). In both sediment regimes, the bioavailability of plutonium and 241Am was low, with specific activity in the tissues 241Am occurred and 241Am uptake from the Thule sediment was enhanced compared to that from lagoon sediments of Enewetak Atoll. Autoradiography studies indicated the presence of hot particles of plutonium in the sediments. The results highlight the importance of purging animals of their gut contents in order to obtain accurate estimates of transuranic transfer from ingested sediments into tissue. It is further suggested that enhanced transuranic uptake by some benthic species could arise from ingestion of highly activity particles and organic-rich detritus present in the sediments. (author)

  3. A thermodynamic study of actinide oxide targets/fuels for americium transmutation

    International Nuclear Information System (INIS)

    A thermodynamic study was performed on the systems Am-O, AmOx-MgO, AmOx-MgAl2O4, Pu-Mg-O and U-Mg-O. Both experimental work (X-ray analyses, oxygen potential measurements etc.) and calculations on the phase diagrams involved were made. The reaction between americium oxide and spinel is expected to form the compound AmAlO3. Isothermal sections have been calculated for AmOx-(MgO, Al2O3), Pu-Mg-O and U-Mg-O at 2000 K using the software package ''Thermo-Calc''. Thermodynamic equilibrium data were used to predict the behaviour of actinide oxides in a reactor. The implication of the results for the technological application is discussed, with emphasis on the effects of the high oxygen potential of AmO2 as compared to the conventional fuel, i.e. UO2. (author)

  4. EURADOS action for determination of americium in skull measures in vivo and Monte Carlo simulation

    International Nuclear Information System (INIS)

    From the Group of WG7 internal dosimetry of the EURADOS Organization (European Radiation Dosimetry group, e.V.) which It coordinates CIEMAT, international action for the vivo measurement of americium has been conducted in three mannequins type skull with detectors of Germanium by gamma spectrometry and simulation by Monte Carlo methods. Such action has been raised as two separate exercises, with the participation of institutions in Europe, America and Asia. Other actions similar precede this vivo intercomparison of measurement and modeling Monte Carlo1. The preliminary results and associated findings are presented in this work. The laboratory of the body radioactivity (CRC) of service counter of dosimetry staff internal (DPI) of the CIEMAT, it has been one of the participants in vivo measures exercise. On the other hand part, the Group of numerical dosimetry of CIEMAT is participant of the Monte Carlo2 simulation exercise. (Author)

  5. Ab initio modelling of the behaviour of helium in americium and plutonium oxides

    International Nuclear Information System (INIS)

    By means of an ab initio plane wave pseudo potential method, plutonium dioxide and americium dioxide are modelled, and the behaviour of helium in both these materials is studied. We first show that a pseudo potential approach in the Generalized Gradient Approximation (GGA) can satisfactorily describe the cohesive properties of PuO2 and AmO2. We then calculate the formation energies of point defects (vacancies and interstitials), as well as the incorporation and solution energies of helium in PuO2 and AmO2. The results are discussed according to the incorporation site of the gas atom in the lattice and to the stoichiometry of PuO2±x and AmO2±x. (authors)

  6. Removal of plutonium and americium from hydrochloric acid waste stream using extraction chromatography

    International Nuclear Information System (INIS)

    Extraction chromatography is under development as a method to lower actinide activity levels in hydrochloric acid (HCl) effluent streams. Successful application of this technique would allow recycle of the largest portion of HCl, while lowering the quantity and improving the form of solid waste generated. The extraction of plutonium and americium from HCl solutions was examined for several commercial and similar laboratory-produced resins coated with n-octyl(phenyl)-N,N-diisobutylcarbamoylmethyphosphine oxide (CMPO) and either tributyl phosphate (TBP), or diamyl amylphosphonate (DAAP). Distribution coefficients for Pu and Am were measured by contact studies in hydrochloric acid solutions over the range of 0.1 - 10.0 N HCl, whole varying REDOX conditions, actinide loading levels, and contact time intervals. Significant differences in the actinide distribution coefficients, and in the kinetics of actinide removal were observed as a function of resin formulation. The usefulness of these resins for actinide removal from HCl effluent streams is discussed

  7. Complex formation of trivalent americium with salicylic acid at very low concentrations

    International Nuclear Information System (INIS)

    For the first time, the complexation of americium(III) with salicylic acid was studied at trace metal concentrations using a 2.0 m Long Path Flow Cell for UV-vis spectroscopy. The detection limit of Am(III) in aqueous solution at pH 3.0 was found to be 5 x 10-9 M. Two Am(III)-salicylate complexes were formed at pH 5.0 in 0.1 M NaClO4, indicated by a clear red shift of the absorption maximum. The absorption spectra obtained from spectrophotometric titration were analyzed by means of factor analysis and complex stabilities were calculated to be log β110 = 2.56 ± 0.08 and log β120 = 3.93 ± 0.19. (author)

  8. Standard practice for The separation of americium from plutonium by ion exchange

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2001-01-01

    1.1 This practice describes the use of an ion exchange technique to separate plutonium from solutions containing low concentrations of americium prior to measurement of the 241Am by gamma counting. 1.2 This practice covers the removal of plutonium, but not all the other radioactive isotopes that may interfere in the determination of 241Am. 1.3 This practice can be used when 241Am is to be determined in samples in which the plutonium is in the form of metal, oxide, or other solid provided that the solid is appropriately sampled and dissolved (See Test Methods C758, C759, and C1168). 1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

  9. Transportability Class of Americium in K Basin Sludge under Ambient and Hydrothermal Processing Conditions

    Energy Technology Data Exchange (ETDEWEB)

    Delegard, Calvin H.; Schmitt, Bruce E.; Schmidt, Andrew J.

    2006-08-01

    This report establishes the technical bases for using a ''slow uptake'' instead of a ''moderate uptake'' transportability class for americium-241 (241Am) for the K Basin Sludge Treatment Project (STP) dose consequence analysis. Slow uptake classes are used for most uranium and plutonium oxides. A moderate uptake class has been used in prior STP analyses for 241Am based on the properties of separated 241Am and its associated oxide. However, when 241Am exists as an ingrown progeny (and as a small mass fraction) within plutonium mixtures, it is appropriate to assign transportability factors of the predominant plutonium mixtures (typically slow) to the Am241. It is argued that the transportability factor for 241Am in sludge likewise should be slow because it exists as a small mass fraction as the ingrown progeny within the uranium oxide in sludge. In this report, the transportability class assignment for 241Am is underpinned with radiochemical characterization data on K Basin sludge and with studies conducted with other irradiated fuel exposed to elevated temperatures and conditions similar to the STP. Key findings and conclusions from evaluation of the characterization data and published literature are summarized here. Plutonium and 241Am make up very small fractions of the uranium within the K Basin sludge matrix. Plutonium is present at about 1 atom per 500 atoms of uranium and 241Am at about 1 atom per 19000 of uranium. Plutonium and americium are found to remain with uranium in the solid phase in all of the {approx}60 samples taken and analyzed from various sources of K Basin sludge. The uranium-specific concentrations of plutonium and americium also remain approximately constant over a uranium concentration range (in the dry sludge solids) from 0.2 to 94 wt%, a factor of {approx}460. This invariability demonstrates that 241Am does not partition from the uranium or plutonium fraction for any characterized sludge matrix. Most

  10. Plutonium and americium concentrations and vertical profiles in some Italian mosses used as bioindicators

    International Nuclear Information System (INIS)

    We have examined the uptake of actinide elements Am and Pu by different species of lichen and moss collected in two locations (Urbino, Central Italy; Alps region, North-east Italy). Plutonium and americium were separated and determined by extraction chromatography, electrodeposition and alpha-spectrometry. This paper summarizes our results with a special emphasis on the vertical profiles of these actinides in two different species of mosses. Several 1-2 cm depth sections were obtained and dated by 210Pb method. A typical peak for 239,240Pu and 241Am was found in the very old moss species ('Sphagnum Compactum') at a depth corresponding to the period 1960-1970 which was the period characterized by the maximum nuclear weapon tests. In a younger moss species ('Neckeria Crispa') no peak was observed and the regression curves showed that Am is more mobile than 239,240Pu and 238Pu. (author)

  11. An electrochemical oxidation process of Am (III) into Am (VI) used to separate the americium of spent fuels reprocessing solutions

    International Nuclear Information System (INIS)

    The aim of this invention is to oxidize by an electrochemical process Am (III) to Am (VI). This process can be used to separate the americium of spent fuels reprocessing solutions. The method consists to add to the aqueous nitric solution containing Am (III) an heteropolyanion able to complex the americium (as for instance the potassium tungstophosphate) and the Ag (II) ion. The Ag (II) ion oxidizes the Am (III) and is reduced into an Ag (I) ion. It is then regenerated by the electrolysis of the solution. After the oxidation of Am (III) into Am (VI), this last ion can be extracted by an adapted organic solvent. With this electrochemical method a yield of 100% Am (VI) is obtained in half a hour. (O.M.). 5 refs., 5 figs., 2 tabs

  12. Separation of oxidized americium from lanthanides by use of pillared metal(IV) phosphate-phosphonate hybrid materials

    International Nuclear Information System (INIS)

    Closing the nuclear fuel cycle in the US poses many challenges, one of which is found in the waste streams, which contain both trivalent lanthanides and actinides. The separation of americium from the raffinate will dramatically reduce the long-term radiotoxicity of the waste. The sorption of americium in both the tri- and pentavalent oxidation states was observed for four M(IV) phosphate-phosphonate ion exchange materials in nitric acid at pH 2. High selectivity was observed for reduced Am(III) with Kd values ca. 6 x 105 mL/g, while the Kd values for Am(V) were much lower. A new method of synthesizing and stabilizing AmO2+ to yield a lifetime of at least 24 h in acidic media using a combination of sodium persulfate and calcium hypochlorite will be described.

  13. Effects of impurities on the size and form of crystals of thorium and americium oxalates and oxides

    International Nuclear Information System (INIS)

    The influence of impurity salts and certain surfactants on the shape and size of thorium and americium oxalate crystals, as well as crystals of their dioxides, prepared at thermolysis of oxalate precipitates, has been investigated. It is shown that during thorium oxalate deposition from solutions, containing 0.8 mol/l thorium and 2 mol/l nitric acid at 96 deg C in the presence of ammonium salts or surfactants larger and monodisperse crystals are grown than in the absence of the above-mentioned substances. Addition of ammonium nitrate in the amount of 0.6 mol/l to solution containing 7.6x10-3 mol/l of americium dioxide particles coincides with the shape of oxalate crystals but their size is reduced by (20-25)% as compared with the initial ones

  14. Combined radiochemical procedure for determination of plutonium, americium and strontium-90 in the soil samples from SNTS

    International Nuclear Information System (INIS)

    The results of combined radiochemical procedure for the determination of plutonium, americium and 90Sr (via measurement of 90Y) in the soil samples from SNTS (Semipalatinsk Nuclear Test Site) are presented. The processes of co-precipitation of these nuclides with calcium fluoride in the strong acid solutions have been investigated. The conditions for simultaneous separation of americium and yttrium using extraction chromatography have been studied. It follows from analyses of real soil samples that the procedure developed provides the chemical recovery of plutonium and yttrium in the range of 50-95 % and 60-95 %, respectively. The execution of the procedure requires 3.5 working days including a sample decomposition study. (author)

  15. Extraction of americium(III) from nitric acid medium by CMPO-TBP extractants in ionic liquid diluent

    International Nuclear Information System (INIS)

    Extraction of americium(III) from nitric acid medium by a solution of tri-n-butylphosphate (TBP) and n-octyl(phenyl)-N,N-diisobutylcarbamoylmethylphosphine oxide (CMPO) in room temperature ionic liquid, l-butyl-3-methyl-imidazolium bis(trifluoromethanesulfonyl)imide (bmimNTf2), was studied and the results were compared with that obtained with CMPO-TBP in n-doddecane (n-DD). The distribution ratio of 241Am(III) in TBP-CMPO/bmimNTf2 was measured as a function of various parameters such as concentrations of nitric acid, CMPO, bmimNO3, NaNO3 and TBP and temperature. Remarkably large distribution ratios were observed for the extraction of americium(III) when bmimNTf2 acted as diluent and the extraction was insignificant in the absence of CMPO. The stoichiometry of metal-solvate in organic phase was determined by the slope analysis of extraction data and it indicated the formation of 1:3 (Am: CMPO) complex in organic phase. Viscosity of TBP-CMPO/bmimNTf2 at various temperatures and enthalpy change accompanied by the extraction of americium(III) were determined and reported in this paper. (orig.)

  16. The behaviour under irradiation of molybdenum matrix for inert matrix fuel containing americium oxide (CerMet concept)

    Science.gov (United States)

    D'Agata, E.; Knol, S.; Fedorov, A. V.; Fernandez, A.; Somers, J.; Klaassen, F.

    2015-10-01

    Americium is a strong contributor to the long term radiotoxicity of high activity nuclear waste. Transmutation by irradiation in nuclear reactors or Accelerator Driven System (ADS, subcritical reactors dedicated to transmutation) of long-lived nuclides like 241Am is therefore an option for the reduction of radiotoxicity of waste packages to be stored in a repository. In order to safely burn americium in a fast reactor or ADS, it must be incorporated in a matrix that could be metallic (CerMet target) or ceramic (CerCer target). One of the most promising matrix to incorporate Am is molybdenum. In order to address the issues (swelling, stability under irradiation, gas retention and release) of using Mo as matrix to transmute Am, two irradiation experiments have been conducted recently at the High Flux Reactor (HFR) in Petten (The Netherland) namely HELIOS and BODEX. The BODEX experiment is a separate effect test, where the molybdenum behaviour is studied without the presence of fission products using 10B to "produce" helium, the HELIOS experiment included a more representative fuel target with the presence of Am and fission product. This paper covers the results of Post Irradiation Examination (PIE) of the two irradiation experiments mentioned above where molybdenum behaviour has been deeply investigated as possible matrix to transmute americium (CerMet fuel target). The behaviour of molybdenum looks satisfying at operating temperature but at high temperature (above 1000 °C) more investigation should be performed.

  17. Consideration of the effect of lymph-node deposition upon the measurement of plutonium and americium in the lungs

    International Nuclear Information System (INIS)

    Measurement of an inhaled radionuclide by external photon counting includes quantities which may be contained in lymph nodes, as well as quantities in the lungs. An overestimate of the lung burden can result, if a portion of the radionuclide were present in the lymph nodes. This problem is analyzed with respect to the measurement of inhaled plutonium containing plutonium-241 and americium-241, when americium-241 has been used as a tracer for the plutonium. Equations are derived which yield the amounts of americium and of plutonium in the lungs and in the lymph nodes as a function of time after exposure and for various translocation and retention parameters. Count histories (count profiles) of actual exposure cases are compared with calculated count profiles in order to gain insight into possible values of the translocation and retention parameters. Comparison is also made with calculated count profiles using values of translocation and retention parameters recommended by the International Commission on Radiological Protection (ICRP) for use with the Task Group Lung Model. The magnitude of the possible overestimate (error factor) was calculated for combinations o

  18. HELIOS: the new design of the irradiation of U-free fuels for americium transmutation

    Energy Technology Data Exchange (ETDEWEB)

    D' Agata, E. [European Commission, Joint Research Centre, Institute for Energy, P.O. Box 2, 1755 ZG Petten (Netherlands); Klaassen, F.; Sciolla, C. [Nuclear Research and Consultancy Group, Dept. Life Cycle and Innovations, P.O. Box 25 1755 ZG Petten (Netherlands); Fernandez-Carretero, A. [European Commission, Joint Research Centre, Institute for Transuranium Elements, P.O. Box 2340, 76125 Karlsruhe (Germany); Bonnerot, J.M. [Commissariat a l' Energie Atomique, DEC/SESC/LC2I CEA-Cadarache, 13108 St. Paul lez Durance Cedex (France)

    2009-06-15

    Americium is one of the radioactive elements that mostly contribute to the radiotoxicity of the nuclear spent fuel. Transmutation of long-lived nuclides like Americium is an option for the reduction of the mass, the radiotoxicity and the decay heat of nuclear waste. The HELIOS irradiation experiment is the last evolution in a series of experiments on americium transmutation. The previous experiments, EFTTRA-T4 and T4bis, have shown that the release or trapping of helium is the key issue for the design of such kind of target. In fact, the production of helium, which is characteristic of {sup 241}Am transmutation, is quite significant. The experiment is carried out in the framework of the 4-year project EUROTRANS of the EURATOM 6. Framework Programme (FP6). Therefore, the main objective of the HELIOS experiment is to study the in-pile behaviour of U-free fuels such as CerCer (Pu, Am, Zr)O{sub 2} and Am{sub 2}Zr{sub 2}O{sub 7}+MgO or CerMet (Pu, Am)O{sub 2}+Mo in order to gain knowledge on the role of the fuel microstructure and of the temperature on the gas release and on the fuel swelling. The experiment was planned to be conducted in the HFR (High Flux Reactor) in Petten (The Netherlands) starting the first quarter of 2007. Because of the innovative aspects of the fuel, the fabrication has had some delays as well as the final safety analyses of the original design showed some unexpected deviation. Besides, the HFR reactor has been unavailable since August 2008. Due to the reasons described above, the experiment has been postponed. HELIOS should start in the first quarter of 2009 and will last 300 full power days. The paper will cover the description of the new design of the irradiation experiment HELIOS. The experiment has been split in two parts (HELIOS1 and HELIOS2) which will be irradiated together. Moreover, due to the high temperature achieved in cladding and to the high amount of helium produced during transmutation the experiment previously designed for a

  19. Uptake of americium-241 by plants from contaminated Chernobyl exclusive zone test site soils

    International Nuclear Information System (INIS)

    Americium-241 was found to accumulate in soils and biological objects of the environment. Its concentration has increased many times after the Chernobyl disaster and can be expected to increase about 40 times in the future. This research concentrated on the contaminated exclusive Chernobyl zone polluted by trace radionuclides, their behavior and accumulation by various plant species. Special attention is devoted to the bioavailability of 241Am to the plants Galium rivale, G. tinctorium, G. aparine, G. intermedium, Berteroa incana, Artemisia absinthium, A. vulgaris, Centaurea borysthenica, C. arenaria, Cirsium arvense, Succissa pratensis, Solidago virgaurea, Linaria vulgaris, Lepidium ruderale, Stenactis annua, Veronica maxima, Verbascum lychnitis, Euphorbia cyparissias, Genista tinctoria, Erigeron canadensis, Oenothera biennis, Betula pendula and Quercus robur, which were collected from the Chernobyl, Kopachi, and Yanov districts. The plant samples of Oenothera biennis, Betula pendula and Quercus robur were collected from the Yanov district, where the soil contamination by 241Am and 137Cs was at the level of 660 and 27 MBq/m2, respectively. Gamma spectroscopy and radiochemical methods were used to estimate the activity concentration of 137Cs, 90Sr, 238Pu, 239+240Pu, 241Am. The radionuclides were measured in the dry green mass of the plant samples and in the dry soils. The contamination of the Oenothera biennis, Betula pendula and Quercus robur samples by 137Cs was (5.8±1,5)x106, (7.4±1.1)x105, and (2.6±0.2)x106 Bq/kg dry mass, respectively, and contamination by 241Am was 47±5, 45±3 and 3.2±0.2 Bq/kg, respectively. The soil-to-plant transfer ratio for 137Cs ranged lay within the interval of 0.2 to 0.03 Bq/kg : Bq/m2, the the transfer ratio for 241Am did not exceed 7x10-5 Bq/kg : Bq/m2. The coefficient of the relative contents of the 241Am/239+240Pu radionuclides in the various plant samples varied from 3.2 to 8.3, while for soil from the Yanov district this

  20. Anomalous aryl strengthening of complexes at americium and europium extraction with alkylenediphospine dioxide from perchloric media

    International Nuclear Information System (INIS)

    Studied was the extraction of americium(3) and europium(3) from perchlorate solutions(0.001 M) with dioxides of alkylenediphosphines of three types: aryl Ph2P(O)CH2(O)PPh2(briefly 4P), and Ph2P(O)(CH2)2(O)PPh2, mixed Ph2P(O)CH2(O)P(C8H17)2 (or 2Ph2Oct) and alkyl (C8H17)2P(O)CH2(O)P(C8H17)2 (or 4 Oct). Trisolvates of MeS3x(ClO4)3 are predominantly formed but americium disolvates are also present upon dilution with dichloroethane. For 4Ph,2Ph2Oct and 4 Oct the concentration is, respectively, 1015, 2x1014, and 1013; for disolvates by 4 orders of magnitude lower which is, nevertheless, by 2 orders of magnitude higher than for nitric acid solutions. The separation coefficient of β Am/Eu for 4Ph attains 6-8. As in the case of nitrate solutions, an anomalous aryl strengthening of the complexes is observed: an increase in the distribution coefficients and extraction constants in the series of 4 Oct - 2Ph 2 Oct - 4Ph, in spite of the introduction of electronegative aryl substituents into the dioxide molecule, which reduce electron density on oxygen atoms and basicity of dioxides. In contrast to nitric acid solutions, observed is a nonlinear effect of a change in basicity on extraction properties upon dilution with dichloroethane (dioxide of 2Ph2 Oct does not occupy an intermediate position but is close to 4Ph). Upon dilution with chloroform the dependence is linear and anomalous effect rises due to a different nature of interactions of dioxides with chloroform. When the bridge increases up to ethylene, an anomalous strengthening of the complexes disappears. However, the distribution coefficients upon extraction with alkyl dioxide are considerably lower, which can be explained by a stronger extraction of perchloric acid

  1. Americium and plutonium in water, biota, and sediment from the central Oregon coast

    International Nuclear Information System (INIS)

    Plutonium-239, 240 and americium-241 were measured in the mussel Mytilus californianus from the region of Coos Bay, OR. The flesh of this species has a plutonium concentration of about 90 fCi/kg, and an Am-241/Pu-239, 240 ratio that is high relative to mixed fallout, ranging between two and three. Transuranic concentrations in sediment, unfiltered water, and filterable particulates were also measured; none of these materials has an Am/Pu ratio as greatly elevated as the mussels, and there is no apparent difference in the Am/Pu ratio of terrestrial runoff and coastal water. Sediment core profiles do not allow accumulation rates or depositional histories to be identified, but it does not appear that material characterized by a high Am/Pu ratio has ever been introduced to this estuary. Other bivalves (Tresus capax and Macoma nasuta) and a polychaete (Abarenicola sp.) do not have an elevated Am/Pu ratio, although the absolute activity of plutonium in the infaunal bivalves is roughly four times that in the mussels

  2. Americium-based oxides: Dense pellet fabrication from co-converted oxalates

    Energy Technology Data Exchange (ETDEWEB)

    Horlait, Denis; Lebreton, Florent [CEA, DEN, DTEC/SDTC/LEMA, 30207 Bagnols-sur-Cèze (France); Gauthé, Aurélie [CEA, DEN, DRCP/SERA/LCAR, 30207 Bagnols-sur-Cèze (France); Caisso, Marie [CEA, DEN, DTEC/SDTC/LEMA, 30207 Bagnols-sur-Cèze (France); Arab-Chapelet, Bénédicte; Picart, Sébastien [CEA, DEN, DRCP/SERA/LCAR, 30207 Bagnols-sur-Cèze (France); Delahaye, Thibaud, E-mail: thibaud.delahaye@cea.fr [CEA, DEN, DTEC/SDTC/LEMA, 30207 Bagnols-sur-Cèze (France)

    2014-01-15

    Mixed oxides are used as nuclear fuels and are notably envisaged for future fuel cycles including plutonium and minor actinide recycling. In this context, processes are being developed for the fabrication of uranium–americium mixed-oxide compounds for transmutation. The purpose of these processes is not only the compliance with fuel specifications in terms of density and homogeneity, but also the simplification of the process for its industrialization as well as lowering dust generation. In this paper, the use of a U{sub 0.85}Am{sub 0.15}O{sub 2±δ} powder synthesized by oxalate co-conversion as a precursor for dense fuel fabrications is assessed. This study notably focuses on sintering, which yielded pellets up to 96% of the theoretical density, taking advantage of the high reactivity and homogeneity of the powder. As-obtained pellets were further characterized to be compared to those obtained via processes based on the UMACS (Uranium Minor Actinide Conventional Sintering) process. This comparison highlights several advantages of co-converted powder as a precursor for simplified processes that generate little dust.

  3. Influence of organic additives on the colour reaction between trivalent americium and arsenazo III

    International Nuclear Information System (INIS)

    The colour reaction of Am(III) with arsenazo III in several hydroorganic media has been examined systematically on the addition of certain polar water-miscible organic solvents in the course of a search for improved and simple spectrophotometric methods for the estimation of americium. Addition of these substances resulted in the stabilization of colour and brought about a drastic enhancement in the absorbance values. The organic additives studied include acetone, acetonitrile, dimethylformamide, dioxane and ethanol. Among the many solvents tested, alcohol and dioxane proved to be the most effective, the highest sensitivity is obtained by using a 60% dioxane-ethanol (1:1) mixture. The apparent molar absorptivity based on Am content is 184616+-9931 mol-1 cm-1 at 655 nm which is about 3 times higher than that attained for the reaction in aqueous medium (65178+-1243). Moreover, this is the highest value reported as yet for its determination. Beer's law is obeyed both in mixed and aqueous media. The effects of some experimental variables on colour development have also been studied to optimize the conditions for the assay of Am. (author)

  4. Speciation and bioavailability of Americium-241 in the fresh water environment

    International Nuclear Information System (INIS)

    Due to its anthropogenic origin, the transuranic americium 241 confronts physiologists with the intriguing question, which mechanisms are involved in the incorporation or elimination of such artificial elements in biological cycles. The investigations on the speciation and bioavailability of 241Am in the freshwater environment aim to establish a relation between the behavior of 241Am in freshwater ecosystems and its availability for biota. In the limnic environment, most often characterized by a high organic load and a low conductivity, the effect of complexation of 241Am with humic acids and competition with trivalent cations such as A1 and Fe, were proven to be significant on the speciation of 241Am. Based on the registration of the 241Am uptake by a large number of freshwater organisms, the crayfish Astacus leptodactylus Eschscholtz was chosen to study the whole-body uptake of 241Am, its corresponding organ distribution and its retention in the animal. The share of external fixation and ingestion in the global uptake, and the effect of speciation on it, were studied more carefully. Other aspects in this physiological part were: the kinetics of 241Am in the hemolymph and the hepatopancreas, and its subcellular distribution in the digestive gland. Finally, by comparing the physiology of 241Am with some other metals (240Pu, 64Cu, 198Au) with analogous or contradictional properties, we tried to find out whether the behavior of 241Am in organisms can be explained from its chemical characteristics

  5. Development and Testing of an Americium/Lanthanide Separation Flowsheet Using Sodium Bismuthate

    Energy Technology Data Exchange (ETDEWEB)

    Jack Law; Bruce Mincher; Troy Garn; Mitchell Greenhalgh; Nicholas Schmitt; Veronica Rutledge

    2014-04-01

    The separation of Am from the lanthanides and curium is a key step in proposed advanced fuel cycle scenarios. The partitioning and transmutation of Am is desirable to minimize the long-term heat load of material interred in a future high-level waste repository. A separation process amenable to process scale-up remains elusive. Given only subtle chemistry differences within and between the ions of the trivalent actinide and lanthanide series this separation is challenging ; however, higher oxidation states of americium can be prepared using sodium bismuthate and separated via solvent extraction using diamylamylphosphonate (DAAP) extraction. Among the other trivalent metals only Ce is also oxidized and extracted. Due to the long-term instability of Am(VI) , the loaded organic phase is readily selectively stripped to partition the actinide to a new acidic aqueous phase. Batch extraction distribution ratio measurements were used to design a flowsheet to accomplish this separation. Additionally, crossflow filtration was investigated as a method to filter the bismuthate solids from the feed solution prior to extraction. Results of the filtration studies, flowsheet development work and flowsheet performance testing using a centrifugal contactor are detailed.

  6. Determination of plutonium americium and curium in soil samples by solvent extraction with trioctylphosphine oxide

    International Nuclear Information System (INIS)

    A method of Pu, Am and Cm determination in soil samples, which was developed for analyzing samples from territories subjected to radioactive contamination as a result of the Chernobyl accident is described. After preliminary treatment the samples were leached by solution of 7 mol/l HNO23+0.3 mol/l KBrO3 during heating. Pu was isolated by extraction with 0.05 mol TOPO from 7 mol/l HNO3. 144Ce and partially remaining in water phase isotopes of Zr, U and Th were isolated in an extraction-chromatographic column with TOPO and PbO2. Then Am and Cm were extracted by 0.2 mol/l TOPO from solution 1 mol/l HLact+0.07 mol/l DTPA+1 mol/l Al(NO3)3. Alpha-activity of both extracted products was determined in liquid scintillation counter. Chemical yield of plutonium counted to 85±10%, that of americium and curium -75±10%. 17 refs

  7. Assessment of radiation doses from residential smoke detectors that contain americium-241

    International Nuclear Information System (INIS)

    External dose equivalents and internal dose commitments were estimated for individuals and populations from annual distribution, use, and disposal of 10 million ionization chamber smoke detectors that contain 110 kBq (3 μCi) americium-241 each. Under exposure scenarios developed for normal distribution, use, and disposal using the best available information, annual external dose equivalents to average individuals were estimated to range from 4 fSv (0.4 prem) to 20 nSv (2 μrem) for total body and from 7 fSv to 40 nSv for bone. Internal dose commitments to individuals under post disposal scenarios were estimated to range from 0.006 to 80 μSv (0.0006 to 8 mrem) to total body and from 0.06 to 800 μSv to bone. The total collective dose (the sum of external dose equivalents and 50-year internal dose commitments) for all individuals involved with distribution, use, or disposal of 10 million smoke detectors was estimated

  8. NMR Evidence for the 8.5 K Phase Transition in Americium Dioxide

    Science.gov (United States)

    Tokunaga, Yo; Nishi, Tsuyoshi; Kambe, Shinsaku; Nakada, Masami; Itoh, Akinori; Homma, Yoshiya; Sakai, Hironori; Chudo, Hiroyuki

    2010-05-01

    We report here the first NMR study of americium dioxide (AmO2). More than 30 years ago, a phase transition was suggested to occur in this compound at 8.5 K based on magnetic susceptibility data, while no evidence had been obtained from microscopic measurements. We have prepared a powder sample of 243AmO2 containing 90 at. % 17O and have performed 17O NMR at temperatures ranging from 1.5 to 200 K. After a sudden drop of the 17O NMR signal intensity below 8.5 K, at 1.5 K we have observed an extremely broad spectrum covering a range of ˜14 kOe in applied field. These data provide the first microscopic evidence for a phase transition as a bulk property in this system. In addition, the 17O NMR spectrum has been found to split into two peaks in the paramagnetic state, an effect which has not been reported for actinide dioxides studied up to now. We suggest that the splitting is induced by self-radiation damage from the alpha decay of 243Am.

  9. Study of biosorbents application on the treatment of radioactive liquid wastes with americium-241

    International Nuclear Information System (INIS)

    The use of nuclear energy for many different purposes has been intensified and highlighted by the benefits that it provides. Medical diagnosis and therapy, agriculture, industry and electricity generation are examples of its application. However, nuclear energy generates radioactive wastes that require suitable treatment ensuring life and environmental safety. Biosorption and bioaccumulation represent an emergent alternative for the treatment of radioactive liquid wastes, providing volume reduction and physical state change. This work aimed to study biosorbents for the treatment of radioactive liquid wastes contaminated with americium-241 in order to reduce the volume and change the physical state from liquid to solid. The biosorbents evaluated were Saccharomyces cerevisiae immobilized in calcium alginate beads, inactivated and free cells of Saccharomyces cerevisiae, calcium alginate beads, Bacillus subtilis, Cupriavidus metallidurans and Ochrobactrum anthropi. The results were quite satisfactory, achieving 100% in some cases. The technique presented in this work may be useful and viable for implementing at the Waste Management Laboratory of IPEN - CNEN/SP in short term, since it is an easy and low cost method. (author)

  10. In Vitro Dissolution Tests of Plutonium and Americium Containing Contamination Originating From ZPPR Fuel Plates

    Energy Technology Data Exchange (ETDEWEB)

    William F. Bauer; Brian K. Schuetz; Gary M. Huestis; Thomas B. Lints; Brian K. Harris; R. Duane Ball; Gracy Elias

    2012-09-01

    Assessing the extent of internal dose is of concern whenever workers are exposed to airborne radionuclides or other contaminants. Internal dose determinations depend upon a reasonable estimate of the expected biological half-life of the contaminants in the respiratory tract. One issue with refractory elements is determining the dissolution rate of the element. Actinides such as plutonium (Pu) and Americium (Am) tend to be very refractory and can have biological half-lives of tens of years. In the event of an exposure, the dissolution rates of the radionuclides of interest needs to be assessed in order to assign the proper internal dose estimates. During the November 2011 incident at the Idaho National Laboratory (INL) involving a ZPPR fuel plate, air filters in a constant air monitor (CAM) and a giraffe filter apparatus captured airborne particulate matter. These filters were used in dissolution rate experiments to determine the apparent dissolution half-life of Pu and Am in simulated biological fluids. This report describes these experiments and the results. The dissolution rates were found to follow a three term exponential decay equation. Differences were noted depending upon the nature of the biological fluid simulant. Overall, greater than 95% of the Pu and 93% of the Am were in a very slow dissolving component with dissolution half-lives of over 10 years.

  11. Solution speciation of plutonium and Americium at an Australian legacy radioactive waste disposal site.

    Science.gov (United States)

    Ikeda-Ohno, Atsushi; Harrison, Jennifer J; Thiruvoth, Sangeeth; Wilsher, Kerry; Wong, Henri K Y; Johansen, Mathew P; Waite, T David; Payne, Timothy E

    2014-09-01

    During the 1960s, radioactive waste containing small amounts of plutonium (Pu) and americium (Am) was disposed in shallow trenches at the Little Forest Burial Ground (LFBG), located near the southern suburbs of Sydney, Australia. Because of periodic saturation and overflowing of the former disposal trenches, Pu and Am have been transferred from the buried wastes into the surrounding surface soils. The presence of readily detected amounts of Pu and Am in the trench waters provides a unique opportunity to study their aqueous speciation under environmentally relevant conditions. This study aims to comprehensively investigate the chemical speciation of Pu and Am in the trench water by combining fluoride coprecipitation, solvent extraction, particle size fractionation, and thermochemical modeling. The predominant oxidation states of dissolved Pu and Am species were found to be Pu(IV) and Am(III), and large proportions of both actinides (Pu, 97.7%; Am, 86.8%) were associated with mobile colloids in the submicron size range. On the basis of this information, possible management options are assessed. PMID:25126837

  12. Comparative study of plutonium and americium bioaccumulation from two marine sediments contaminated in the natural environment

    Energy Technology Data Exchange (ETDEWEB)

    Hamilton, T.F.; Smith, J.D. (Melbourne Univ., Parkville (Australia). Dept. of Inorganic Chemistry); Fowler, S.W.; LaRosa, J.; Holm, E. (International Atomic Energy Agency, Monaco-Ville (Monaco). Lab. of Marine Radioactivity); Aarkrog, A.; Dahlgaard, H. (Risoe National Lab., Roskilde (Denmark))

    1991-01-01

    Plutonium and americium sediment-animal transfer was studied under controlled laboratory conditions by exposure of the benthic polychaete Nereis diversicolor (O. F. Mueller) to marine sediments contaminated by a nuclear bomb accident (near Thule, Greenland) and nuclear weapons testing (Enewetak Atoll). In both sediment regimes, the bioavailability of plutonium and {sup 241}Am was low, with specific activity in the tissues <1% (dry wt) than in the sediments. Over the first three months, a slight preference in transfer of plutonium over {sup 241}Am occurred and {sup 241}Am uptake from the Thule sediment was enhanced compared to that from lagoon sediments of Enewetak Atoll. Autoradiography studies indicated the presence of hot particles of plutonium in the sediments. The results highlight the importance of purging animals of their gut contents in order to obtain accurate estimates of transuranic transfer from ingested sediments into tissue. It is further suggested that enhanced transuranic uptake by some benthic species could arise from ingestion of highly activity particles and organic-rich detritus present in the sediments. (author).

  13. Use of radioisotopes in the study of tetracycline analytical application. Extraction of compounds formed between tetracycline and neptunium and americium elements

    International Nuclear Information System (INIS)

    The behavior of tetracycline as complexing agent, in solvent extraction studies of neptunium and americium, using benzyl alcohol as the organic phase, is presented. By using radioactive tracers of 239Np and 241Am the extraction percent of these elements were determined as a function of pH in the absence and in the presence of several masking agents. The influence of shaking time and the use of different types of supporting eletrolytes upon the extraction behavior was also studied. The extraction curves obtained using EDTA as masking agent show that tetracycline can be used for neptunium and americium separation. In this condition neptunium is extracted into the organic phase and americium remains in the aqueous phase. (Author)

  14. Sorption of plutonium and americium on repository, backfill and geological materials relevant to the JNFL low-level radioactive waste repository at Rokkasho-Mura

    International Nuclear Information System (INIS)

    An integrated program of batch sorption experiments and mathematical modeling has been carried out to study the sorption of plutonium and americium on a series of repository, backfill and geological materials relevant to the JNFL low-level radioactive waste repository at Rokkasho-Mura. The sorption of plutonium and americium on samples of concrete, mortar, sand/bentonite, tuff, sandstone and cover soil has been investigated. In addition, specimens of bitumen, cation and anion exchange resins, and polyester were chemically degraded. The resulting degradation product solutions, alongside solutions of humic and isosaccharinic acids were used to study the effects on plutonium sorption onto concrete, sand/bentonite and sandstone. The sorption behavior of plutonium and americium has been modeled using the geochemical speciation program HARPHRQ in conjunction with the HATCHES database

  15. Biosorption of Americium-242 by saccharomyces cerevisiae: preliminary evaluation and mechanism

    International Nuclear Information System (INIS)

    As an important radioisotope in nuclear industry and other fields, americium-241 is one of the most serious contamination concerns duo to its high radiation toxicity and long half-life. In this experiment, the biosorption of 241Am from solution by a fungus, Saccharomyces cerevisiae (S. cerevisiae), and the effects of various experimental conditions on the biosorption and the mechanism were explored. The preliminary results showed that S. cerevisiae is a very efficient biosorbent. An average of more than 99% of the total 241Am could be removed by S. cerevisiae of 2.1g/L (dry weight) from 241Am solutions of 2.22MBq/L -555 MBq/L (Co). The adsorption equilibrium was achieved within 1 hour and the optimum pH ranged 1-3. The culture times of more than 16 hours were suitable and the efficient adsorption of 241Am by the S. cerevisiae could be noted. The biosorption of 241Am by the decomposed cell wall, protoplasm or cell membrane of S. cerevisiae was same efficient as by the intact fungus, but the some components of S. cerevisiae, such as protein and acylation group had obvious effect on adsorption. When the concentrations of coexistent Eu3+, Nd3+ were 100 times more than that of 241Am, the adsorption rates would drop to 65%. However, most of the investigated acidic ions have no significant influence on the 241Am adsorption but minute change of pH value, while the saturated EDTA can strong inhibit the biosorption of 241Am.. (authors)

  16. Characterization of uranium, plutonium, neptunium, and americium in HLW supernate for LLW certification

    International Nuclear Information System (INIS)

    The 1S Manual requires that High Level Waste (HLW) implement a waste certification program prior to sending waste packages to the E-Area vaults. To support the waste certification plan, the HLW supernate inventory of uranium, plutonium, neptunium and americium have been characterized. This characterization is based on the chemical, isotopic and radiological properties of these elements in HLW supernate. This report uses process knowledge, solubility data, isotopic inventory data and sample data to determine if any isotopes of the aforementioned elements will exceed the minimum reportable quantity (MRQ) for waste packages contaminated with HLW supernate. If the MRQ can be exceeded for a particular nuclide, then a method for estimating the waste package content is provided. Waste packages contaminated from HLW supernate do not contain sufficient U-233, U-234, U-235, U-236, U-238, Pu-239, Pu-240, Pu-241, Pu-242 or Am-241 to warrant separate reporting on the shipping manifest. Calculations show that, on average, more than 100 gallons of supernate is required to exceed the PAC (package acceptance criteria) for each of these nuclides. Thus it is highly unlikely that the PAC would be exceeded for these nuclides and unlikely that the MRQ would be exceeded. These nuclides should be manifested as zero for waste packages contaminated with HLW supernate. The only actinide isotopes that may exceed the MRQ are Np-237 and Pu-238. The recommended method to calculate the amount of these two isotopes in waste packages contaminated with HLW supernate is to ratio them to the measured Cs-137 activity

  17. Some elements for a revision of the americium reference biokinetic model

    International Nuclear Information System (INIS)

    The interpretation of individual activity measurement after a contamination by 241Am or its parent nuclide 241Pu is based on the reference americium (Am) biokinetic model published by the International Commission on Radiological Protection in 1993 [International Commission on Radiological Protection. Age-dependent doses to members of the public from intake of radionuclides: Part 2 Ingestion dose coefficients. ICRP Publication 67. Ann. ICRP 23(3/4) (1993)]. The authors analysed the new data about Am biokinetics reported afterwards to propose an update of the current model. The most interesting results, from the United States Transuranium and Uranium Registries post-mortem measurement database [Filipy, R. E. and Russel, J. J. The United States Transuranium and Uranium Registries as sources for actinide dosimetry and bio-effects. Radiat. Prot. Dosim. 105(1-4), 185-187 (2003)] and the long-term follow-up of cases of inhalation intake [Malatova, I., Foltanova, S., Beckova, V., Filgas, R., Pospisilova, H. and Hoelgye, Z. Assessment of occupational doses from internal contamination with 241Am. Radiat. Prot. Dosim. 105(1-4), 325-328 (2003)], seemed to show that the current model underestimates the retention in the massive soft tissues and overestimates the retention in the skeleton and the late urinary excretion. However, a critical review of the data demonstrated that all were not equally reliable and suggested that only a slight revision of the model, possibly involving a change in the balance of activity between massive soft tissues, cortical and trabecular bone surfaces, may be required. (authors)

  18. The treatment of liquid radioactive waste containing Americium by using a cation exchange method

    International Nuclear Information System (INIS)

    A research in the treatment of a liquid radioactive waste containing americium has been done. The liquid radioactive waste used in this research was standard solution of U dan Ce with the initial activity of 100 ppm. The experimental investigation is aimed at a study of the effects of the waste pH, the column dimension of IR-120 cation exchanger which is expressed as L/D, the flow rate of a liquid waste and the influence of thiocyanate as a complex agent against the efficiency of a decontamination for uranium and cerium element. The experiment was done by passing downward the feed of uranium and cerium solution into an IR-120 type of cation exchanger with the L/D of 11.37. From the experimental parameters done in this research where the influence of waste pH was varied from 3 - 8, the geometric column (L/D) 11.37, the liquid flow rate was from 2.5 - 10 ml/m and the thiocyanate concentration was between 100 ppm-500 ppm can be concluded that the optimum operational condition for the ion exchange achieved were the waste pH for uranium = 4 and the waste pH for cerium = 6, the flow rate = 2.5 ml/men. From the given maximum value of DF for uranium = 24 (DE = 95.83%) and of DF for cerium = 40 (DE = 97.5%), it can also be concluded that this investigation is to be continued in order that the greater value of DF/DE can be achieved

  19. A study of plutonium and americium concentrations in seaspray on the southern Scottish coast

    International Nuclear Information System (INIS)

    Seaspray and seawater have been collected from the southern Scottish coast and, for comparison, Cumbria in northwest England during 1989 and 1991. The occurrence of sea-to-land transfer of the actinides plutonium and americium in seaspray was observed on these coasts using muslin screens (a semi-quantitative technique most efficient for collecting large spray droplets) and high volume conventional air samplers. The actinides and fine particulate in the spray were present in relatively higher concentrations than measured in the adjacent seawater, i.e. the spray was enriched in particulate actinides. The net efficiency of the muslim screens in collecting airborne plutonium isotopes and 241Am generally appeared to be about 20%. A review of earlier published concentrations of 239+240Pu and 241Am measured in aerosol and deposition for over a year several tens of metres inland was carried out. This suggested that airborne activities are up to a factor of 5 times higher in Cumbria than southern Scotland. However, neither the new data collected in 1989 and 1991 nor this older data suggests any enhancement of seaspray actinide enrichment in southern Scotland compared to Cumbria. This finding contrasts with earlier, more limited, comparisons that have been carried out which suggested such a difference. There is clear evidence of considerable localised spatial and temporal variability in aerosol actinide enrichment over the beaches in both areas. Enrichments varies between 20 and 500 relative to the adjacent surf zone waters. However, the average enrichment in spray based on the continuous measurements made further inland is likely to be at the lower end of this range. (author)

  20. Reduction of. systematic error of In-vivo measurement of americium 241 activity in the skull

    International Nuclear Information System (INIS)

    Excretion analysis and in vivo measuring methods are used for estimation of internal contamination by 241Am. In vivo measurements of the lung are suitable in short time after time of intake when the way of the intake is inhalation. In vivo measurements of the activity in the liver or in the skeleton could be performed at a later time. Detection of radionuclide activity in the liver is quite difficult because it is necessary to distinguish liver activity from the activity of surrounding tissues i.e. lung and skeleton. The skull or knees are the most suitable., for activity assessment in the skeleton. The skull is the most appropriate for measurements because it represents about 15% of total skeleton mass and contributions to measured activity of surrounding tissues are small. Americium activity in the skull could be measured with different instrumentation and in various geometries. Setting of two semiconductors detectors placed 3 cm over temporal region of the skull is used in NRPI. Calibration of the system was done by several head phantoms, in this process was observed that detection efficiencies depend on size of the phantoms. The aim of the paper is to express character of the efficiency as function of the size of skull in order to obtain more accurate value of the activity and decrees its uncertainty. Simulations of head by simplified geometric shapes, i.e. spheres and rotary ellipsoids, is in coherence with phantoms of big size (UCIN, BPAM-0001), but for small phantoms occurred quite serious discrepancy. Activity of real cases determined by calibration with phantom BPAM-0001 (reference phantom) is reduced from 9 to 44 %, when eq. 2 is used and relative uncertainty is reduced from 32% to maximum 12%. (authors)

  1. Transport of plutonium, americium, and curium from soils into plants by roots

    International Nuclear Information System (INIS)

    For assessing the dose from radionuclides in agricultural products by ingestion it is necessary to know the soil to plant transfer factors. The literature was entirely investigated, in order to judge the size of the soil to plant transfer factors. In total, 92 publications - from 1948 to 1978 -have been evaluated. As result, transfer factors from 10-9 to 10-3 have been found for Plutonium, and from 10-6 to 1 for Americium. For Curium only few data are available in literature. The considerable variation of the measured transfer factors is based on the dependence of these transfer factors from the ion exchange capacity of soils, from the amount of organic materials, from the pH-value, and from the mode of contamination. There are, in any case, contradictory data, although there has been detected a dependence of the transfer factors from these parameters. Chelating agenst increase the transfer factors to approximately 1300. As well, fertilizers have an influence on the size of the transfer factors - however, the relationships have been scarcely investigated. The distribution of actinides within the individual parts of plants has been investigated. The highest concentrations are in the roots; in the plant parts above ground the concentration of actinides decreases considerably. The most inferior transfer factors were measured for the respective seed or fruits. The soil to plant transfer factors of actinides are more dependend on the age of the plants within one growing period. At the beginning of the period, the transfer factor is considerably higher than at the end of this period. With respect to plants with a growing period of several years, correlations are unknown. (orig.)

  2. Inert matrices, uranium-free plutonium fuels and americium targets. Synthesis of CAPRA, SPIN and EFTTRA studies

    International Nuclear Information System (INIS)

    A first selection of inert-matrix materials, actinide support alone (Pu and Am based), and compound materials, U free plutonium burning fuels and heterogeneous americium targets are discussed. Basic properties, fabrication, and reprocessing studies, European in-pile and out-of-pile tests, performed recently in the framework of CAPRA, SPIN and EFTTRA programs, are reviewed here. Taking into account these studies and on the bases of the different requirements to be met in each of the fuels and targets, a number of materials have been selected as 'promising candidates'. Trends for further research on these materials are established. (author)

  3. Final Report on the Demonstration of Disposal of Americium and Curium Legacy Material Through the High Level Waste System

    International Nuclear Information System (INIS)

    This report provides the results of experimental demonstrations related to processing of a legacy solution containing americium and curium through the High Level Waste (HLW) system. The testing included eight experiments covering the baseline, mitigation, and enhanced nitrate processing studies. In general, each experiment studied the mixtures generated over a period of time to emulate the lifecycle of actual sludge in the High Level Waste system. While the data in previous reports remain valid, this report supercedes all the previous reports and provides a collective overview of the work

  4. Effect of a long-term release of plutonium and americium into an estuarine and coastal sea ecosystem

    International Nuclear Information System (INIS)

    This paper discusses the general problem of speciation of plutonium and americium in aquatic ecosystems and the implications relative to their fate in those systems. The following conclusions were reached: several oxidation states of plutonium coexist in the natural environment; the effect of environmental changes such as pH and Esub(h) values and complexes are probably the cause of these various oxidation states; a clearer definition of the 'concentration factor' should be given in view of the important role the sediments play in supplying plutonium for transfer through the food web. (author)

  5. Microstructure and elemental distribution of americium-containing MOX fuel under the short-term irradiation tests

    International Nuclear Information System (INIS)

    In order to investigate the effect of americium addition to MOX fuels on the irradiation behavior, the 'Am-1' program is being conducted in JAEA. The Am-1 program consists of two short-term irradiation tests of 10-minute and 24-hour irradiations and a steady-state irradiation test. The short-term irradiation tests were successfully completed and the post irradiation examinations (PIEs) are in progress. The PIEs for Am-containing MOX fuels focused on the microstructural evolution and redistribution behavior of Am at the initial stage of irradiation and the results to date are reported. (author)

  6. Development of a methodology for the determination of americium and thorium by ICP-AES and their inter-element effect

    International Nuclear Information System (INIS)

    Due to the scarcity of good quality uranium resources, the growth of nuclear technology in India is dependent on the utilization of the vast thorium resources. Therefore, Advance Heavy Water Reactor is going to acquire significant role in the scenario of Indian nuclear technology, where (Th, Pu)O2 will be utilized as fuel in the outermost ring of the reactor core. This will lead to a complex matrix containing thorium as well as americium, which is formed due to β-decay of plutonium. The amount of americium is dependent on the burn up and the storage time of the Pu based fuels. In the present case, attempt was made to develop a method for the determination of americium as well as thorium by ICP-AES. Two emission lines of americium were identified and calibration curves were established for determination of americium. Though the detection limit of 283.236 nm line (5 ng mL-1) of americium was found to be better than that of 408.930 nm (11 ng mL-1), the former line is significantly interfered by large amount of thorium. Three analytical lines (i.e. 283.242, 283.730 and 401.913 nm) of thorium were identified and calibration curves were established along with their detection limits. It was observed that 283.242 and 401.913 nm line are having similar detection limits (18 and 13 ng mL-1, respectively) which are better than that of 283.730 nm (60 ng mL-1). This can be attributed to the high background of 283.273 nm channel of thorium. The spectral interference study revealed that even small amount of americium has significant contribution on 283.242 nm channel of thorium while the other two channels remain practically unaffected. Considering both these facts, spectral interference and analytical performance (detection limits and sensitivity), it was concluded that 401.913 nm line is the best analytical line out of the three lines for determination of thorium in presence of americium. (author)

  7. Effect of radiolysis on leachability of plutonium and americium from 76-101 glass. [Glass containing 2 mole % plutonium

    Energy Technology Data Exchange (ETDEWEB)

    Nash, K.L.; Fried, S.; Friedman, A.M.; Susak, N.; Rickert, P.; Sullivan, J.C.; Karim, D.P.; Lam, D.J.

    1982-01-01

    One aspect of the leachability of actinide-bearing glass which has not been adequately addressed is the effect of radiolysis of the system (glass-water) on the amount of actinides liberated from the glass. In the present study, we have investigated the leaching of plutonium and americium from 76-101 glass samples (containing 2 mole % plutonium) in the presence of a one megaRad/hour gamma-radiation field. The presence of the radiation field was found to increase the leaching rate of both plutonium and americium by a factor of five. Speciation studies of the plutonium in the leachate indicate that the plutonium is present predominantly in the higher oxidation states, Pu(V) and Pu(VI) and that it is significantly associated with colloidal particles. Examination of the glass surfaces with x-ray photoemission spectroscopy, XPS, both before and after leaching was carried out; these studies showed lower surface concentrations of plutonium in the samples of glass leached in the radiation field. 1 figure, 3 tables.

  8. Osteosarcoma induction by plutonium-239, americium-241 and neptunium-237 : the problem of deriving risk estimates for man

    International Nuclear Information System (INIS)

    Spontaneous bone cancer (osteosarcoma) represents only about 0.3% of all human cancers, but is well known to be inducible in humans by internal contamination with radium-226 and radium-224. plutonium-239, americium-241 and neptunium-237 form, or will form, the principal long-lived alpha particle emitting components of high activity waste and burnt-up nuclear fuel elements. These three nuclides deposit extensively in human bone and although, fortunately, no case of a human osteosarcoma induced by any of these nuclides is known, evidence from animal studies suggests that all three are more effective than radium-226 in inducing osteosarcoma. The assumption that the ratio of the risk factors, the number of osteosarcoma expected per 10000 person/animal Gy, for radium-226 and any other bone-seeking alpha-emitter will be independent of animal species has formed the basis of all the important studies of the radiotoxicity of actinide nuclides in experimental animals. The aim of this communication is to review the risk factors which may be calculated from the various animal studies carried out over the last thirty years with plutonium-237, americium-241 and neptunium-237 and to consider the problems which may arise in extrapolating these risk factors to homo sapiens

  9. Plutonium and americium in Arctic waters, the North Sea and Scottish and Irish coastal zones (in Fucus, Mytilus and Patella)

    International Nuclear Information System (INIS)

    Plutonium and americium have been measured in surface waters of the Greenland and Barents Seas and in the northern North Sea from 1980 through 1984. Measurements in water and biota, Fucus, Mytilus and Patella, were carried out in North-English and Scottish waters in 1982 and Fucus samples were collected from the Irish coast in 1983. Fallout is found to dominate as a source of 239+240Pu north of latitude 650N, while for 238Pu a substantial fraction originates from European nuclear fuel reprocessing facilities. The 238Pu/239+240Pu isotope ratio provides clear evidence of the transport of effluent plutonium from the latter to Spitsbergen waters. Fallout plutonium in Arctic waters has a residence time of the order of several years, while for Pu from Sellafield we estimate mean residence times of 11-15 months in Scottish waters and, tentatively, 1.5-3 y during transport from the North Channel (north of the Irish Sea) to Spitsbergen. 241Am found in Arctic waters probably originates from the decay of fallout 241Pu and, like Pu, tentatively has a residence time of the order of several years. Americium from Sellafield has an estimated mean residence time of 4-6 months in Scottish waters. (author)

  10. Experimental Study on Behavior of Americium in Pyrochemical Process of Nitride Fuel Cycle

    International Nuclear Information System (INIS)

    R and D on the transmutation of long-lived minor actinides (MA) by the accelerator-driven system (ADS) using nitride fuels is underway at JAEA. In regard to reprocessing technology, pyrochemical process has several advantages in case of treating spent fuel with large decay heat and fast neutron emission, and recovering highly enriched N-15. In the pyrochemical reprocessing, plutonium and MA are dissolved in LiCl-KCl eutectic melts and selectively recovered into liquid cadmium (Cd) cathode by molten salt electrorefining. The electrochemical behavior in LiCl-KCl eutectic melts and the subsequent nitride formation behavior of plutonium and MA recovered in liquid Cd cathode are investigated. In this paper, recent results on electrochemical study of americium (Am) on electrolyses of AmN in LiCl-KCl eutectic melts and nitride formation of Am recovered in the liquid Cd cathode are presented. Electrochemical behavior of Am on anodic dissolution of AmN and recovery of Am into a liquid Cd cathode by electrolyses in LiCl-KCl eutectic melts was investigated by transient electrochemical techniques. The formal standard potential of Am(III)/Am(0) obtained with the liquid Cd electrode is more positive than that calculated for the solid metal electrode. The potential shift is considered to be attributed to the lowering of the activity of Am by the formation of the intermetallic compound with Cd. Potentiostatic electrolyses of AmN in LiCl-KCl eutectic melts containing AmCl3 at 773 K were carried out. Nitrogen gas generated by the anodic dissolution of AmN was observed, and the current efficiency was obtained from the ratio of the amount of released nitrogen gas and the passed electric charge to be 20 - 28 %. Am was recovered as Am-Cd alloy in the liquid Cd cathode, in which AmCd6 type phase was identified besides Cd phase. The recovered Am was converted to AmN by the nitridation-distillation combined method, in which the Am-Cd alloy was heated in nitrogen gas stream at 973 K. These

  11. Preconcentration of low levels of americium and plutonium from waste waters by synthetic water-soluble metal-binding polymers with ultrafiltration

    International Nuclear Information System (INIS)

    A preconcentration approach to assist in the measurement of low levels of americium and plutonium in waste waters has been developed based on the concept of using water-soluble metal-binding polymers in combination with ultrafiltration. The method has been optimized to give over 90% recovery and accountability from actual waste water. (author)

  12. Chemical behaviour of trivalent and pentavalent americium in saline NaCl-solutions. Studies of transferability of laboratory data to natural conditions. Interim report. Reported period: 1.2.1993-31.12.1993; Chemisches Verhalten von drei- und fuenfwertigem Americium in Salinen NaCl-Loesungen. Untersuchung der Uebertragbarkeit von Labordaten auf natuerliche Verhaeltnisse. Zwischenbericht. Berichtszeitraum 1.2.1993-31.12.1993

    Energy Technology Data Exchange (ETDEWEB)

    Runde, W.; Kim, J.I.

    1994-09-15

    In order to clarify the chemical behaviour of Americium in saline aqueous systems relevant for final storage this study deals with the chemical reactions of trivalent and pentavalent Americium in NaCl-solutions under the influence of radiolysis from its own alpha radiation. The focus of the study was on investigating the geologically relevant reactions, such as hydrolysis or carbonate- and chloride complexing in solid-liquid equilibriums. Comprehensive measurements on solubility and spectroscopic studies in NaCl-solutions were carried out in a CO{sub 2}-free atmosphere and 10{sup -2} atm CO{sub 2} partial pressure. Identification and characterisation of the AM (III) and AM(V) solid phases were supplemented by structural research with the chemically analogue EU (III) and Np(V) compounds. The alpha-radiation induced radiolysis in saline NaCl solutions and the redox behaviour of Americium which was influenced thereby were spectroscopically quantified. (orig.) [Deutsch] Zur Klaerung des chemischen Verhaltens von Americium in endlagerrelevanten salinen aquatischen Systemen befasst sich die vorliegende Arbeit mit den chemischen Reaktionen des drei- und fuenfwertigen Americiums in NaCl-Loesungen unter dem Einfluss der Radiolyse durch die eigene {alpha}-Strahlung. Der Schwerpunkt dieser Arbeit lag auf der Untersuchung der geologisch relevanten Reaktionen, wie Hydrolyse sowie Carbonat- und Chloridkomplexierung in fest-fluessig Gleichgewichtssystemen. Hierzu wurden umfassende Loeslichkeitsmessungen und spektroskopische Untersuchungen in NaCl-Loesungen, sowohl unter CO{sub 2}-freier Atmosphaere als auch unter 10{sup -2} atm CO{sub 2}-Partialdruck, durchgefuehrt. Die Identifizierung und Charakterisierung der Am(III)- und Am(V)-Festphasen wurde ergaenzt durch strukturelle Untersuchungen mit den chemisch analogen Eu(III)- und Np(V)-Verbindungen. Die von der {alpha}-Strahlung induzierte Radiolyse in salinen NaCl-Loesungen und das dadurch beeinflusste Redoxverhalten von Americium

  13. Influence of an alkoxy group on bis-triazinyl-pyridines for selective extraction of americium(III)

    International Nuclear Information System (INIS)

    The extraction of americium(III), curium(III), and lanthanides(III) from nitric acid by 2,6-bis-(5,6-dimethyl-[1,2,4]-triazin-3-yl)-pyridine and 2,6-bis-(5,6-dimethyl-[1,2,4]-triazin- 3-yl)-4-methoxy-pyridine was studied. The physico-chemical properties of these ligands, such as the protonation and complexation constants, were also determined to describe the influence of different substituent groups. The selectivity of substituted-BTP was confirmed both in complexation and in solvent extraction experiments. The presence of an alkoxy-group in position 4 of the pyridine decreases the BTP selectivity. Influence of a long alkyl chain on protonation and complexation constants was also studied with 2,6-bis-(5,6-dimethyl-[1,2,4]- triazin-3-yl)-4-dodecyloxy-pyridine. (authors)

  14. Solvent extraction of europium and americium into phenyltrifluoromethyl sulfone by using synergistic mixture of hydrogen dicarbollylcobaltate and 'classical' CMPO

    International Nuclear Information System (INIS)

    Extraction of microamounts of europium and americium by a phenyltrifluoromethyl sulfone (FS 13) solution of hydrogen dicarbollylcobaltate (H+B-) in the presence of octyl-phenyl-N,N-diisobutylcarbamoylmethyl phosphine oxide ('classical' CMPO, L) has been investigated. The equilibrium data have been explained assuming that the complexes HL+, HL2+, ML23+, ML33+ and ML43+ (M3+ Eu3+, Am3+) are extracted into the organic phase. The values of extraction and stability constants of the cationic complex species in FS 13 saturated with water have been determined. It was found that the stability constants of the corresponding complexes EuLn3+ and AmLn3+, where n 2, 3, 4 and L is 'classical' CMPO, in water-saturated FS 13 are comparable. (author)

  15. Recovery, purification and concentration of plutonium and americium from the aqueous wastes discharged in the reprocessing process studies

    International Nuclear Information System (INIS)

    For recovering and purifying plutonium and americium from the aqueous wastes occurring in the process studies on reprocessing, a standard procedure has been established for use in the laboratory works, through the preliminary tests of the precipitation as hydroxides and the anion exchange in nitrate media. The procedure was proven in the treatment of actual wastes, of which the results were contributed to determine the process conditions in the plutonium purification and product concentration of the JAERI Reprocessing Test Plant. The preliminary tests also include washing of U and Am recovery from the anion-exchanger in nitrate media, direct ion-exchange recovery of Pu from the TBP phase and elution of Am from the cation-exchanger. (auth.)

  16. Plutonium and americium in fish, shellfish and seaweed in the Irish environment and their contribution to dose

    International Nuclear Information System (INIS)

    Plutonium and americium activity concentrations in fish and shellfish landed in Ireland in the period 1988 to 1997 are presented. Activity concentrations in fish are low and often below detection limits, while those in mussels and oysters sampled on the northeast coast show no significant signs of decline. The estimated doses to hypothetical typical and heavy seafood consumers remain below 1 μSv yr-1 (committed effective dose).Plutonium activity concentrations measured in Fucus vesiculosus around the Irish coastline have not fallen appreciably in the ten year period between 1986 and 1996. Furthermore, the mean 238Pu/239,240Pu ratio of 0.17±0.05 in Fucus vesiculosus from the west coast of Ireland demonstrates the increasing significance of Sellafield-derived plutonium in those waters. (Copyright (c) 1999 Elsevier Science B.V., Amsterdam. All rights reserved.)

  17. The bone volume effect on the dosimetry of plutonium-239 and americium-241 in the skeleton of man and baboon

    International Nuclear Information System (INIS)

    Studies were undertaken using bone removed from young adult baboons, which had been contaminated with plutonium-239 at various times prior to sacrifice, and human bone from adult male (USTR Case 246), who had received an internal deposition of americium-241 as a result of a glove-box explosion 11 years prior to his death. The baboon bone was supplied by the CEA, France, and the human bone by the United States Transuranium registry. The bone samples, examined by qualitative and quantitative autoradiography with CR 39 detectors, demonstrated the rapid redistribution of bone surface-seeking radionuclides in younger primates due to growth and the slower, bone turnover driven redistribution in the adult human bone. In both species, primary and secondary surface deposits of radionuclide remained conspicious despite bone activity; true volumization of radionuclide was seldom seen. The dosimetric implications of these findings are discussed. (author) 21 refs.; 6 figs.; 4 tabs

  18. Comparative XRPD and XAS study of the impact of the synthesis process on the electronic and structural environments of uranium-americium mixed oxides

    Science.gov (United States)

    Prieur, D.; Lebreton, F.; Martin, P. M.; Caisso, M.; Butzbach, R.; Somers, J.; Delahaye, T.

    2015-10-01

    Uranium-americium mixed oxides are potential compounds to reduce americium inventory in nuclear waste via a partitioning and transmutation strategy. A thorough assessment of the oxygen-to-metal ratio is paramount in such materials as it determines the important underlying electronic structure and phase relations, affecting both thermal conductivity of the material and its interaction with the cladding and coolant. In 2011, various XAS experiments on U1-xAmxO2±δ samples prepared by different synthesis methods have reported contradictory results on the charge distribution of U and Am. This work alleviates this discrepancy. The XAS results confirm that, independently of the synthesis process, the reductive sintering of U1-xAmxO2±δ leads to the formation of similar fluorite solid solution indicating the presence of Am+III and U+V in equimolar proportions.

  19. Stability of penta- and hexavalent americium in the solutions of sodium peroxydisulfate and sodium bromate at intensive internal α-irradiation

    International Nuclear Information System (INIS)

    The spectrometric method has been used for studying the dependence of the rates of radiolytic reduction of Am(5) and (6) on the initial concentration of sodium persulfate and bromate, Am(5) and (6), acidity, and the dose rate of inner alpha-irradiation of the solutions. The high dose rates of inner alpha-irradiation of solutions (up to 3.25x1021 eV/lxmin-250Ci/l) have been attained with the aid of curium isotopes. The stability of americium (6) ions towards the action of ionizing radiation in solutions of sodium persulfate and bromate has been shown to be considerable lower than that of americium (5). The chemical difference has been shown in radiolytic behaviour between Am(5) and Am(6) ions in solutions of sodium persulfate and bromate. The equations have been derived showing the dependence of the rates of Am(6) and Am(5) reduction of different variables

  20. A Density Functional Study of Atomic Hydrogen and Oxygen Chemisorption on the Relaxed (0001) Surface of Double Hexagonal Close Packed Americium

    OpenAIRE

    Dholabhai, P. P.; Atta-Fynn, R.; A.K. Ray

    2009-01-01

    Ab initio total energy calculations within the framework of density functional theory have been performed for atomic hydrogen and oxygen chemisorption on the (0001) surface of double hexagonal packed americium using a full-potential all-electron linearized augmented plane wave plus local orbitals method. Chemisorption energies were optimized with respect to the distance of the adatom from the relaxed surface for three adsorption sites, namely top, bridge, and hollow hcp sites, the adlayer str...

  1. Distribution, retention and dosimetry of plutonium and americium in the rat, dog and monkey after inhalation of an industrial-mixed uranium and plutonium oxide aerosol

    International Nuclear Information System (INIS)

    This study provides information on patterns of radiation dose in laboratory animals after inhalation exposure to an aerosol of one form of mixed uranium and plutonium oxide. The aerosol contained a mixture of UO2 and 750 deg C heat-treated PuO2 obtained from the ball milling operation in a mixed-oxide fuel fabrication process. Americium-241 from the decay of 241Pu was also present in the PuO2 matrix. Fischer-344 rats, Beagle dogs, and Cynomolgus and Rhesus monkeys inhaled aerosols re-generated from dry mixed oxide powders with particle size distribution characteristics similar to those observed in samples collected at the industrial site. Clearance from the lung and distribution in other tissues of the plutonium from this UO2 + PuO2 admixture was similar to what has been observed for PuO2 from laboratory-produced aerosols. The UO2-PuO2 aerosol was relatively insoluble in the lungs of all species. Monkeys and rats cleared plutonium and americium from their lungs faster than dogs. Very little plutonium or americium translocated within the first 2 yr after exposure to tissues other than tracheobronchial lymph nodes. The greater accumulation of plutonium and americium in the tracheobronchial lymph nodes of dogs as compared to monkeys and rats combined with the more rapid initial clearance of these radionuclides from the lungs of rats and monkeys suggests that errors could result from using data from a single animal species to estimate risk to humans from inhalation of these industrial aerosols. (author)

  2. Experimental study of Americium-241 biokinetics in Homarus Gammarus lobster. Analysis of the accumulation and detoxication mechanisms at the sub-cellular level

    International Nuclear Information System (INIS)

    The Americium 241 radioelement accumulation and elimination rate and mechanisms in the lobster organism have been experimentally studied; incorporation and detoxification capacities of each organ are evaluated. The existence of various biological compartments is shown; the major role of the digestive gland in accumulation of the radioelement, its distribution towards the various organs, and its resorption is comprehensively described, with an analysis at the subcellular and molecular levels. 401 p., 65 fig., 43 tab., 428 ref

  3. Comparative XRPD and XAS study of the impact of the synthesis process on the electronic and structural environments of uranium–americium mixed oxides

    Energy Technology Data Exchange (ETDEWEB)

    Prieur, D., E-mail: dam.prieur@gmail.com [European Commission, Joint Research Centre, Institute for Transuranium Elements, P.O. Box 2340, D-76125 Karlsruhe (Germany); Lebreton, F. [CEA, DEN, DTEC/SDTC/LEMA, 30207 Bagnols-sur-Cèze cedex (France); Martin, P.M. [CEA, DEN, DEC/SESC/LLCC, 13108 Saint-Paul-Lez-Durance cedex (France); Caisso, M. [CEA, DEN, DTEC/SDTC/LEMA, 30207 Bagnols-sur-Cèze cedex (France); Butzbach, R. [Helmholtz Zentrum Dresden Rossendorf (HZDR), Institute of Radiochemistry, P.O. Box 10119, 01314 Dresden (Germany); Somers, J. [European Commission, Joint Research Centre, Institute for Transuranium Elements, P.O. Box 2340, D-76125 Karlsruhe (Germany); Delahaye, T. [CEA, DEN, DTEC/SDTC/LEMA, 30207 Bagnols-sur-Cèze cedex (France)

    2015-10-15

    Uranium–americium mixed oxides are potential compounds to reduce americium inventory in nuclear waste via a partitioning and transmutation strategy. A thorough assessment of the oxygen-to-metal ratio is paramount in such materials as it determines the important underlying electronic structure and phase relations, affecting both thermal conductivity of the material and its interaction with the cladding and coolant. In 2011, various XAS experiments on U{sub 1−x}Am{sub x}O{sub 2±δ} samples prepared by different synthesis methods have reported contradictory results on the charge distribution of U and Am. This work alleviates this discrepancy. The XAS results confirm that, independently of the synthesis process, the reductive sintering of U{sub 1−x}Am{sub x}O{sub 2±δ} leads to the formation of similar fluorite solid solution indicating the presence of Am{sup +III} and U{sup +V} in equimolar proportions. - Graphical abstract: Formation of (U{sup IV/V},Am{sup III})O{sup 2} solid solution by sol–gel and by powder metallurgy. - Highlights: • Uranium–americium mixed oxides were synthesized by sol–gel and powder metallurgy. • Fluorite solid solutions with similar local environment have been obtained. • U{sup V} and Am{sup III} are formed in equimolar proportions.

  4. An experimental study of americium-241 biokinetics in the Lobster Homarus Gammarus. Analysis of the accumulation/storage and detoxification processes at the subcellular level

    International Nuclear Information System (INIS)

    An experimental study of americium-241 kinetics has been conducted in the lobster Homarus gammmarus. The investigations were conducted at all the levels from the whole body to the subcellular and molecular levels. The animals were contaminated by a single or chronic ingestion of 241 Am labelled mussels. Assessments of accumulation, elimination and distribution of the radionuclide were established on organisms kept in the laboratory; they made it possible to demonstrate the importance of the digestive gland in the radionuclide transfer pathways. The preliminary results led to structural then ultrastructural investigations of the digestive gland in association with radioautographic studies and cellular extractions methods. Four cellular types were demonstrated, only two of them being implied in the radionuclide retention, the former being responsible for americium intake and the latter for its long-term retention. By means of biochemical techniques, subcellular accumulation was studied and the organelles implied in the nuclide retention were specified. Finally, a method of cellular nuclei dissociation was developed; it made it possible to analyse the molecular nature of americium ligands and to demonstrate the function of the protein nuclear matrix in the nuclide retention

  5. A new method for the determination of plutonium and americium using high pressure microwave digestion and alpha-spectrometry or ICP-SMS

    International Nuclear Information System (INIS)

    Plutonium and americium are radionuclides particularly difficult to measure in environmental samples because they are a-emitters and therefore necessitate a careful separation before any measurement, either using radiometric methods or ICP-SMS. Recent developments in extraction chromatography resins such as EichromR TRU and TEVA have resolved many of the analytical problems but drawbacks such as low recovery and spectral interferences still occasionally occur. Here, we report on the use of the new EichromR DGA resin in association with TEVA resin and high pressure microwave acid leaching for the sequential determination of plutonium and americium in environmental samples. The method results in average recoveries of 83 ± 15% for plutonium and 73 ± 22% for americium (n = 60), and a less than 10% deviation from reference values of four IAEA reference materials and three samples from intercomparisons exercises. The method is also suitable for measuring 239Pu in water samples at the μBq/l level, if ICP-SMS is used for the measurement. (author)

  6. Comparative XRPD and XAS study of the impact of the synthesis process on the electronic and structural environments of uranium–americium mixed oxides

    International Nuclear Information System (INIS)

    Uranium–americium mixed oxides are potential compounds to reduce americium inventory in nuclear waste via a partitioning and transmutation strategy. A thorough assessment of the oxygen-to-metal ratio is paramount in such materials as it determines the important underlying electronic structure and phase relations, affecting both thermal conductivity of the material and its interaction with the cladding and coolant. In 2011, various XAS experiments on U1−xAmxO2±δ samples prepared by different synthesis methods have reported contradictory results on the charge distribution of U and Am. This work alleviates this discrepancy. The XAS results confirm that, independently of the synthesis process, the reductive sintering of U1−xAmxO2±δ leads to the formation of similar fluorite solid solution indicating the presence of Am+III and U+V in equimolar proportions. - Graphical abstract: Formation of (UIV/V,AmIII)O2 solid solution by sol–gel and by powder metallurgy. - Highlights: • Uranium–americium mixed oxides were synthesized by sol–gel and powder metallurgy. • Fluorite solid solutions with similar local environment have been obtained. • UV and AmIII are formed in equimolar proportions

  7. Preliminary results from uranium/americium affinity studies under experimental conditions for cesium removal from NPP ''Kozloduy'' simulated wastes solutions

    International Nuclear Information System (INIS)

    We use the approach described by Westinghouse Savannah River Company using ammonium molybdophosphate (AMP) to remove elevated concentrations of radioactive cesium to facilitate handling waste samples from NPP Kozloduy. Preliminary series of tests were carried out to determine the exact conditions for sufficient cesium removal from five simulated waste solutions with concentrations of compounds, whose complexing power complicates any subsequent processing. Simulated wastes solutions contain high concentrations of nitrates, borates, H2C2O4, ethylenediaminetetraacetate (EDTA) and Citric acid, according to the composition of the real waste from the NPP. On this basis a laboratory treatment protocol was created. This experiment is a preparation for the analysis of real waste samples. In this sense the results are preliminary. Unwanted removal of non-cesium radioactive species from simulated waste solutions was studied with gamma spectrometry with the aim to find a compromise between on the one hand the AMP effectiveness and on the other hand unwanted affinity to AMP of Uranium and Americium. Success for the treatment protocol is defined by proving minimal uptake of U and Am, while at the same time demonstrating good removal effectiveness through the use of AMP. Uptake of U and Am were determined as influenced by oxidizing agents at nitric acid concentrations, proposed by Savannah River National laboratory. It was found that AMP does not significantly remove U and Am when concentration of oxidizing agents is more than 0.1M for simulated waste solutions and for contact times inherent in laboratory treatment protocol. Uranium and Americium affinity under experimental conditions for cesium removal were evaluated from gamma spectrometric data. Results are given for the model experiment and an approach for the real waste analysis is chosen. Under our experimental conditions simulated wastes solutions showed minimal affinity to AMP when U and Am are most probably in the

  8. Characteristics of plutonium and americium contamination at the former U.K. atomic weapons test ranges at Maralinga and Emu

    Energy Technology Data Exchange (ETDEWEB)

    Burns, P.A.; Cooper, M.B.; Lokan, K.H.; Wilks, M.J.; Williams, G.A. [Australian Radiation Lab., Melbourne, VIC (Australia)

    1995-11-01

    Physico-chemical studies on environmental plutonium are described, which provide data integral to an assessment of dose for the inhalation of artificial actinides by Australian Aborigines living a semi-traditional lifestyle at Maralinga and Emu, sites of U.K. atomic weapons tests between 1953 and 1963. The most significant area, from a radiological perspective, is the area contaminated by plutonium in a series of ``one point`` safety trials in which large quantities of plutonium were dispersed explosively at a location known as Taranaki. The activity distribution of plutonium and americium with particle size is quite different from the mass distribution, as a considerably higher proportion of the activity is contained in the finer (inhalable) fraction than of the mass. Except in areas which were disturbed through ploughing during a cleanup in 1967, most the activity remains in the top 1 cm of the surface. Much of the activity is in particulate form, even at distances > 20 km from the firing sites, and discrete particles have been located even at distances beyond 100 km. Data are presented which permit the assessment of annual committed doses through the inhalation pathway, for Aborigines living a semi-traditional lifestyle in the areas affected by the Taranaki firings in particular. (author).

  9. Evaluation of synthetic water-soluble metal-binding polymers with ultrafiltration for selective concentration of americium and plutonium

    International Nuclear Information System (INIS)

    Routine counting methods and ICP-MS are unable to directly measure the new US Department of Energy (DOE) regulatory level for discharge waters containing alpha-emitting radionuclides of 30 pCi/L total alpha or the 0.05 pCi/L regulatory level for Pu or Am activity required for surface waters at the Rocky Flats site by the State of Colorado. This inability indicates the need to develop rapid, reliable, and robust analytical techniques for measuring actinide metal ions, particularly americium and plutonium. Selective separation or preconcentration techniques would aid in this effort. Water-soluble metal-binding polymers in combination with ultrafiltration are shown to be an effective method for selectively removing dilute actinide ions from acidic solutions of high ionic strength. The actinide-binding properties of commercially available water-soluble polymers and several polymers which have been reported in the literature were evaluated. The functional groups incorporated in the polymers were pyrrolidone, amine, oxime, and carboxylic, phosphonic, or sulfonic acid. The polymer containing phosphonic acid groups gave the best results with high distribution coefficients and concentration factors for 241Am(III) and 238Pu(III)/(IV) at pH 4 to 6 and ionic strengths of 0.1 to 4

  10. Characterization of a Sealed Americium-Beryllium (AmBe) Source by Inductively Coupled Plasma Mass Spectrometry

    International Nuclear Information System (INIS)

    Two Americium-Beryllium neutron sources were dismantled, sampled (sub-sampled) and analyzed via inductively coupled plasma mass spectrometry (ICP-MS). Characteristics such as 'age' since purification, actinide content, trace metal content and inter and intra source composition were determined. The 'age' since purification of the two sources was determined to be 25.0 and 25.4 years, respectively. The systematic errors in the 'age' determination were ± 4 % 2s. The amount and isotopic composition of U and Pu varied substantially between the sub-samples of Source 2 (n=8). This may be due to the physical means of sub-sampling or the way the source was manufactured. Source 1 was much more consistent in terms of content and isotopic composition (n=3 sub-samples). The Be-Am ratio varied greatly between the two sources. Source 1 had an Am-Be ratio of 6.3 ± 52 % (1s). Source 2 had an Am-Be ratio of 9.81 ± 3.5 % (1s). In addition, the trace element content between the samples varied greatly. Significant differences were determined between Source 1 and 2 for Sc, Sr, Y, Zr, Mo, Ba and W.

  11. Use of radioanalytical methods for determination of uranium, neptunium, plutonium, americium and curium isotopes in radioactive wastes

    International Nuclear Information System (INIS)

    Activated charcoal is a common type of radioactive waste that contains high concentrations of fission and activation products. The management of this waste includes its characterization aiming the determination and quantification of the specific radionuclides including those known as Difficult-to-Measure Radionuclides (RDM). The analysis of the RDM's generally involves complex radiochemical analysis for purification and separation of the radionuclides, which are expensive and time-consuming. The objective of this work was to define a methodology for sequential analysis of the isotopes of uranium, neptunium, plutonium, americium and curium present in a type of radioactive waste, evaluating chemical yield, analysis of time spent, amount of secondary waste generated and cost. Three methodologies were compared and validated that employ ion exchange (TI + EC), extraction chromatography (EC) and extraction with polymers (ECP). The waste chosen was the activated charcoal from the purification system of primary circuit water cooling the reactor IEA-R1. The charcoal samples were dissolved by acid digestion followed by purification and separation of isotopes with ion exchange resins, extraction and chromatographic extraction polymers. Isotopes were analyzed on an alpha spectrometer, equipped with surface barrier detectors. The chemical yields were satisfactory for the methods TI + EC and EC. ECP method was comparable with those methods only for uranium. Statistical analysis as well the analysis of time spent, amount of secondary waste generated and cost revealed that EC method is the most effective for identifying and quantifying U, Np, Pu, Am and Cm present in charcoal. (author)

  12. Use of radioactive methods for determination of uranium, neptunium, plutonium, americium and curium isotopes in waste radioactive

    International Nuclear Information System (INIS)

    Activated charcoal is a common type of radioactive waste that contains high concentrations of fission and activation products. The management of this waste includes its characterization aiming the determination and quantification of the specific radionuclides including those known as Difficult-to-Measure Radionuclides (RDM). The analysis of the RDM's generally involves complex radiochemical analysis for purification and separation of the radionuclides, which are expensive and time-consuming. The objective of this work was to define a methodology for sequential analysis of the isotopes of uranium, neptunium, plutonium, americium and curium present in a type of radioactive waste, evaluating chemical yield, analysis of time spent, amount of secondary waste generated and cost. Three methodologies were compared and validated that employ ion exchange (TI+EC), extraction chromatography (EC) and extraction with polymers (ECP). The waste chosen was the activated charcoal from the purification system of primary circuit water cooling the reactor IEA-R1. The charcoal samples were dissolved by acid digestion followed by purification and separation of isotopes with ion exchange resins, extraction and chromatographic extraction polymers. Isotopes were analyzed on an alpha spectrometer, equipped with surface barrier detectors. The chemical yields were satisfactory for the methods TI+EC and EC. ECP method was comparable with those methods only for uranium. Statistical analysis as well the analysis of time spent, amount of secondary waste generated and cost revealed that EC method is the most effective for identifying and quantifying U, Np, Pu, Am and Cm present in charcoal. (author)

  13. Migration of the fission products strontium, technetium, iodine, cesium, and the actinides neptunium, plutonium, americium in granitic rock

    International Nuclear Information System (INIS)

    Rock samples were taken from drilling cores in granitic and granodioritic rock, and small (2x2x2 cm) rock tablets from the drilling cores were exposed to a groundwater solution containing one of the studied elements at race levels. The concentration of the element versus penetration depth in the rock tablet was measured radiometrically. The sorption on the mineral faces and the migration into the rock was studied, by an autoradiographic technique. The cationic fission products strontium and cesium had apparent diffusivities of 10-13-10-14 m2/s. They migrate mainly in fissures or filled fractures containing e.g., calcite, epidote or chlorite or in veins with hgih capacity minerals (e.g. biotite). The anionic fission products iodine and technetium had apparent diffusivities of about 10-14 m2/s. These species migrate along mineral boundaries and in open fractures and to a minor extent in high capacity mineral veins. The migration of the actinides neptunium, plutonium and americium is very slow (in the mm-range after 2-3 years contact time). The apparent diffusivities were about 10-15 m2/s. The actinide migration into the rock was largely confined to fissures. (orig./HP)

  14. Distribution of plutonium, americium, and several rare earth fission product elements between liquid cadmium and LiCl-KCl eutectic

    International Nuclear Information System (INIS)

    Separation factors were measured that describe the partition between molten cadmium and molten LiCl-KCl eutectic of plutonium, americium, praseodymium, neodymium, cerium, lanthanum, gadolinium, dysprosium, and yttrium. The temperature range was 753-788 K, and the range of concentrations was that allowed by the sensitivity of the chemical analysis methods. Mean separation factors were derived for Am-Pu, Nd-Am, Nd-Pu, Nd-Pr, Gd-La, Dy-La, La-Ce, La-Nd, Y-La, and Y-Nd. Where previously published data were available, agreement was good. For convenience, the following series of separation factors relative to plutonium was derived by combining the measured separation factors: Pu, 1.00 (basis); Am, 1.54; Pr, 22.0; Nd, 23.4; Ce, 26; La, 70; Gd, 77; Dy, 270; Y, 3000. These data are used in calculating the distribution of the actinide and rare earth elements in the prochemical reprocessing of spent fuel from the Integral Fast Reactor. (orig.)

  15. Characteristics of plutonium and americium contamination at the former U.K. atomic weapons test ranges at Maralinga and Emu

    International Nuclear Information System (INIS)

    Physico-chemical studies on environmental plutonium are described, which provide data integral to an assessment of dose for the inhalation of artificial actinides by Australian Aborigines living a semi-traditional lifestyle at Maralinga and Emu, sites of U.K. atomic weapons tests between 1953 and 1963. The most significant area, from a radiological perspective, is the area contaminated by plutonium in a series of ''one point'' safety trials in which large quantities of plutonium were dispersed explosively at a location known as Taranaki. The activity distribution of plutonium and americium with particle size is quite different from the mass distribution, as a considerably higher proportion of the activity is contained in the finer (inhalable) fraction than of the mass. Except in areas which were disturbed through ploughing during a cleanup in 1967, most the activity remains in the top 1 cm of the surface. Much of the activity is in particulate form, even at distances > 20 km from the firing sites, and discrete particles have been located even at distances beyond 100 km. Data are presented which permit the assessment of annual committed doses through the inhalation pathway, for Aborigines living a semi-traditional lifestyle in the areas affected by the Taranaki firings in particular. (author)

  16. Measured solubilities and speciations of neptunium, plutonium, and americium in a typical groundwater (J-13) from the Yucca Mountain region

    International Nuclear Information System (INIS)

    Solubility and speciation data are important in understanding aqueous radionuclide transport through the geosphere. They define the source term for transport retardation processes such as sorption and colloid formation. Solubility and speciation data are useful in verifying the validity of geochemical codes that are part of predictive transport models. Results are presented from solubility and speciation experiments of 237NpO2+, 239Pu4+, 241Am3+/Nd3+, and 243Am3+ in J-13 groundwater (from the Yucca Mountain region, Nevada, which is being investigated as a potential high-level nuclear waste disposal site) at three different temperatures (25 degree, 60 degree, and 90 degree C) and pH values (5.9, 7.0, and 8.5). The solubility-controlling steady-state solids were identified and the speciation and/or oxidation states present in the supernatant solutions were determined. The neptunium solubility decreased with increasing temperature and pH. Plutonium concentrations decreased with increasing temperature and showed no trend with pH. The americium solutions showed no clear solubility trend with increasing temperature and increasing pH

  17. The role of natural organic matter in the migration behaviour of americium in the Boom Clay - Part 1: migration experiments

    International Nuclear Information System (INIS)

    Full text of publication follows: In demonstrating the suitability of Boom Clay as reference site for studying the disposal of radioactive waste, the role of the relatively high amount of Natural Organic Matter (NOM) present in the Boom Clay on the mobility of critical radionuclides needs to be investigated thoroughly. It is generally accepted that trivalent actinides and lanthanides form strong complexes with humic substances. Complexation of these trivalent radionuclides with NOM present in the Boom Clay may therefore have two opposite effects. If complexed by the aqueous phase NOM (the mobile NOM), the radionuclide transport will be governed by the mobility of these dissolved radionuclide- NOM species. If complexed by the solid phase NOM (the immobile NOM) the migration will be retarded. One of the aims of the EC projects TRANCOM-Clay and TRANCOM-II was to investigate the role of mobile NOM as radionuclide carrier in order to develop a conceptual model for inclusion in a performance assessment (PA) model. The migration behaviour of Americium (used as an analogue for the critical radionuclide Pu) was investigated by complexing 241Am with radiolabelled (14C-labelled) NOM before passing through undisturbed Boom Clay cores contained in columns. The use of two different radionuclides, allows the migration behaviour of both the NOM and the Am to be followed. The results of the migration experiments showed that the Am-NOM complexes dissociated when they came into contact with Boom Clay and that the bulk of Am became immobilised (either as Am complexed to immobile NOM or sorbed to the mineral phase). Only a small percentage of the complex persisted as 'stabilised' Am-OM complex which exhibited slow dissociation kinetics upon moving through the Boom Clay. When the applied radionuclide source also contains Am in the form of an inorganic solid phase (when Am is applied above the solubility limit), a continuous source of Am exists to form 'temporarily stabilised' Am

  18. Molten salt extraction (MSE) of americium from plutonium metal in CaCl2-KCl-PuCl3 and CaCl2-PuCl3 salt systems

    International Nuclear Information System (INIS)

    Molten salt extraction (MSE) of americium-241 from reactor-grade plutonium has been developed using plutonium trichloride salt in stationary furnaces. Batch runs with oxidized and oxide-free metal have been conducted at temperature ranges between 750 and 945C, and plutonium trichloride concentrations from one to one hundred mole percent. Salt-to-metal ratios of 0.10, 0.15, and 0 30 were examined. The solvent salt was either eutectic 74 mole percent CaCl2 endash 26 mole percent KCl or pure CaCl2. Evidence of trivalent product americium, and effects of temperature, salt-to-metal ratio, and oxide contamination on the americium extraction efficiency are given. 24 refs, 20 figs, 13 tabs

  19. Plutonium, americium and radiocaesium in the marine environment close to the Vandellos I nuclear power plant before decommissioning

    International Nuclear Information System (INIS)

    The Vandellos nuclear power plant (NPP), releasing low-level radioactive liquid waste to the Mediterranean Sea, is the first to be decommissioned in Spain, after an incident which occurred in 1989. The presence, distribution and uptake of various artificial radionuclides (radiocaesium, plutonium and americium) in the environment close to the plant were studied in seawater, bottom sediments and biota, including Posidonia oceanica, fish, crustaceans and molluscs. Seawater, sediments and Posidonia oceanica showed enhanced levels in the close vicinity of the NPP, although the effect was restricted to its near environment. Maximum concentrations in seawater were 11.6±0.5 Bq m-3 and 16.9±1.2 mBq m-3 for 137Cs and 239,240Pu, respectively. When sediment concentrations were normalized to excess 210Pb, they showed both the short-distance transport of artificial radionuclides from the Vandellos plant and the long-distance transport of 137Cs from the Asco NPP. Posidonia oceanica showed the presence of various gamma-emitters attributed to the impact of the Chernobyl accident, on which the effect of the NPP was superimposed. Seawater, sediment and Posidonia oceanica collected near the plant also showed an enhancement of the plutonium isotopic ratio above the fallout value. The uptake of these radionuclides by marine organisms was detectable but limited. Pelagic fish showed relatively higher 137Cs concentrations and only in the case of demersal fish was the plutonium isotopic ratio increased. The reported levels constitute a set of baseline values against which the impact of the decommissioning operations of the Vandellos I NPP can be studied

  20. Determination by gamma-ray spectrometry of the plutonium and americium content of the Pu/Am separation scraps. Application to molten salts; Determination par spectrometrie gamma de la teneur en plutonium et en americium de produits issus de separation Pu/Am. Application aux bains de sels

    Energy Technology Data Exchange (ETDEWEB)

    Godot, A. [CEA Valduc, Dept. de Traitement des Materiaux Nucleaires, 21 - Is-sur-Tille (France); Perot, B. [CEA Cadarache, Dept. de Technologie Nucleaire, Service de Modelisation des Transferts et Mesures Nucleaires, 13 - Saint-Paul-lez-Durance (France)

    2005-07-01

    Within the framework of plutonium recycling operations in CEA Valduc (France), americium is extracted from molten plutonium metal into a molten salt during an electrolysis process. The scraps (spent salt, cathode, and crucible) contain extracted americium and a part of plutonium. Nuclear material management requires a very accurate determination of the plutonium content. Gamma-ray spectroscopy is performed on Molten Salt Extraction (MSE) scraps located inside the glove box, in order to assess the plutonium and americium contents. The measurement accuracy is influenced by the device geometry, nuclear instrumentation, screens located between the sample and the detector, counting statistics and matrix attenuation, self-absorption within the spent salt being very important. The purpose of this study is to validate the 'infinite energy extrapolation' method employed to correct for self-attenuation, and to detect any potential bias. We present a numerical study performed with the MCNP computer code to identify the most influential parameters and some suggestions to improve the measurement accuracy. A final uncertainty of approximately 40% is achieved on the plutonium mass. (authors)

  1. Recovery of plutonium and americium from laboratory acidic waste solutions using tri-n-octylamine and octylphenyl-N-N- diisobutylcarbamoylmethylphosphine oxide.

    Science.gov (United States)

    Michael, K M; Rizvi, G H; Mathur, J N; Kapoor, S C; Ramanujam, A; Iyer, R H

    1997-11-01

    Plutonium from acidic waste solutions has been recovered quantitatively using tri-n-octylamine (TnOA) in xylene and americium using a mixture of octylphenyl-N-N- diisobutylcarbamoylmethylphosphine oxide (CMPO) and TBP in dodecane by extraction and extraction chromatographic methods. The Pu ( IV ) TnOA species extracted into the organic phase from higher nitric acid concentrations has been confirmed as (R(3)NH)(2)Pu(NO(3))(6) (where R(3)N = TnOA by employing slope analysis as well as spectrophotometric studies. PMID:18966958

  2. Theoretical investigation of pressure-induced structural transitions in americium using GGA+U and hybrid density functional theory methods

    DEFF Research Database (Denmark)

    Verma, Ashok K.; Modak, P.; Sharma, Surinder M.;

    2013-01-01

    First-principles calculations have been performed for americium (Am) metal using the generalized gradient approximation + orbital-dependent onsite Coulomb repulsion via Hubbard interaction (GGA+U) and hybrid density functional theory (HYB-DFT) methods to investigate various ground state properties...... phase in order to match the experimental data. Thus, neither the GGA+U nor the HYB-DFT methods are able to describe the energetics of Am metal properly in the entire pressure range from 0 GPa to 50 GPa with a single choice of their respectiveU and α parameters. Low binding-energy peaks in the...

  3. Dissertation on the computer-based exploitation of a coincidence multi parametric recording. Application to the study of the disintegration scheme of Americium 241

    International Nuclear Information System (INIS)

    After having presented the meaning of disintegration scheme (alpha and gamma emissions, internal conversion, mean lifetime), the author highlights the benefits of the use of multi-parametric chain for the recording of correlated parameters, and of the use of a computer for the analysis of bi-parametric information based on contour lines. Using the example of Americium 241, the author shows how these information are obtained (alpha and gamma spectrometry, time measurement), how they are chosen, coded, analysed and stored, and then processed by contour lines

  4. Uptake of curium (244Cm) by five benthic marine species (Arenicola marina, Cerastoderma edule, Corophium volutator, Nereis diversicolor and Scrobicularia plana): comparison with americium and plutonium

    International Nuclear Information System (INIS)

    Curium (244Cm) uptake from contaminated sea water was studied in five benthic marine species: two bivalve molluscs (Scrobicularia plana and Cerastoderma edule), two polychaete annelids (Arenicola marina and Nereis diversicolor) and one amphidpod crustacean (Corophium volutator). The concentrations in the whole organisms relative to the concentration in the sea water (concentration factors) were: 700 for the amphipods (after 11 d of accumulation), 140 for the cockles (after 28 d), 80 for the scrobicularia (after 23d) and approx. 30 for the two annelids (after > 20 d). All species except S. plana accumulated americium and curium similarly; S. plana accumulated similar amounts of curium and plutonium. (author)

  5. Uptake of curium (/sup 244/Cm) by five benthic marine species (Arenicola marina, Cerastoderma edule, Corophium volutator, Nereis diversicolor and Scrobicularia plana): comparison with americium and plutonium

    Energy Technology Data Exchange (ETDEWEB)

    Miramand, P.; Germain, P.; Arzur, J.C.

    1987-01-01

    Curium (/sup 244/Cm) uptake from contaminated sea water was studied in five benthic marine species: two bivalve molluscs (Scrobicularia plana and Cerastoderma edule), two polychaete annelids (Arenicola marina and Nereis diversicolor) and one amphidpod crustacean (Corophium volutator). The concentrations in the whole organisms relative to the concentration in the sea water (concentration factors) were: 700 for the amphipods (after 11 d of accumulation), 140 for the cockles (after 28 d), 80 for the scrobicularia (after 23d) and approx. 30 for the two annelids (after > 20 d). All species except S. plana accumulated americium and curium similarly; S. plana accumulated similar amounts of curium and plutonium.

  6. Investigation of solubility of cesium, strontium, barium, rare-earth, uranium and americium fluorides in acid nitrosyl fluoride (NOFx3HF)

    International Nuclear Information System (INIS)

    Solubility of Am and other elements, which are fission products, in acid nitrosylfluoride has been studied. Cesium fluoride has maximum solubility; uranium tetrafluoride is also noticeably soluble; americium trifluoride is practically insoluble; fluorides of rare earth elements are slightly soluble in NOFx3HF. Analysis of the solid phase obtained after treating the mixture of the above fluorides with acid nitrosylfluoride has shown that cesium fluoride reacts with NOFx3HF with the formation of an acid salt (CsFxHF), whereas fluorides of alkaline and rare earth elements remain unchanged. The behaviour of a mixture of cesium, barium, and lanthanum fluorides in the process of three-multiple treating with acid nitrosylfluoride has been studied. It is shown that more than 98% of cesium fluoride and 5% of barium fluoride pass into the mother liquor while lanthanum fluoride remains completely in the solid phase. The data on americium fluoride solubility in acid nitrosylfluoride have indicated that it behaves in the same way as fluorides of rare earth elements; it is practically insoluble in HOFx3HF

  7. Determining the americium transmutation rate and fission rate by post-irradiation examination within the scope of the ECRIX-H experiment

    International Nuclear Information System (INIS)

    The ECRIX-H experiment aims to assess the feasibility of transmuting americium micro-dispersed in an inert magnesia matrix under a locally moderated neutron flux in the Phénix reactor. A first set of examinations demonstrated that pellet behaviour was satisfactory with moderate swelling at the end of the irradiation. Additional post-irradiation examinations needed to be conducted to confirm the high transmutation rate so as to definitively conclude on the success of the ECRIX-H experiment. This article presents and discusses the results of these new examinations. They confirm the satisfactory behaviour of the MgO matrix not only during the basic irradiation but also during post-irradiation thermal transients. These examinations also provide additional information on the behaviour of fission products both in the americium-based particles and in the MgO matrix. These results particularly validate the transmutation rate predicted by the calculation codes using several different analytical techniques. The fission rate is also determined

  8. Inhaled americium dioxide

    International Nuclear Information System (INIS)

    This project includes experiments to determine the effects of Zn-DTPA therapy on the retention, translocation and biological effects of inhaled 241AmO2. Beagle dogs that received inhalation exposure to 241AmO2 developed leukopenia, clincial chemistry changes associated with hepatocellular damage, and were euthanized due to respiratory insufficiency caused by radiation pneumonitis 120 to 131 days after pulmonary deposition of 22 to 65 μCi 241Am. Another group of dogs that received inhalation exposure to 241AmO2 and were treated daily with Zn-DTPA had initial pulmonary deposition of 19 to 26 μCi 241Am. These dogs did not develop respiratory insufficiency, and hematologic and clinical chemistry changes were less severe than in the non-DTPA-treated dogs

  9. Partitioning studies in China and the separation of americium and fission product rare earths with dialkyl phosphinic acid and its thio-substituted derivatives

    International Nuclear Information System (INIS)

    Studies on the TRPO extractions process for recovering actinides from highly active waste (HAW) and its application to the pretreatment of Chinese HAW are described. The removal of Sr by di-cyclohexyl 18 crown 6 and the removal of Cs by spherical titanium ferrous hexa-cyanate from acidic waste are also described. Results of the extraction of trivalent americium and fission product rare earths (FPREs) by dialkyl-phosphinic, dialkyl-mono-thio-phosphinic and dialkyl-di-thio-phosphinic acids are reported. Dialkyl-thio-phosphinic acid (commercial product Cyanex 301, alkyl =2, 4, 4-methyl-pentyl) shows very high selectivity towards Am. Using 1M Cyanex 301 -kerosene as extractant, 99.9 % Am can be separated from 0.5M(Pr+Nd)(NO3)3 solution with 3-4 extraction stages and 3-4 scrubbing stages. (authors)

  10. Theoretical and experimental study of the bio-geochemical behaviour of americium 241 in simplified rhizosphere conditions. Application to a calcareous agricultural soil

    International Nuclear Information System (INIS)

    Americium 241, is one of the most radio-toxic contaminant produced during the nuclear fuel cycle. It can be found in all environmental compartments, in particular the soils. The main goals of this study are to identify, quantify and model the effect of the main factors controlling the mobility of 241Am in the rhizosphere and the agricultural soils. The physico-chemical parameters of the soil and of the soil solution, the potential role of microorganisms on the sorption-desorption processes, and the speciation of americium in solution have been more particularly studied. 241Am remobilization has been studied at the laboratory using leaching experiments performed in controlled conditions on reworked calcareous soils artificially contaminated with 241Am. The soil samples have been washed out in different hydrodynamic conditions by solutions with various compositions. The eluted solution has been analyzed (pH, conductivity, ionic composition, Fetot, organic acids, 241Am) and its bacterial biomass content too. The overall results indicate that 241Am remobilization is contrasted and strongly linked with the condition under study (pH, ionic strength, glucose and/or citrate concentration). Therefore, a solution in equilibrium with the soil or containing small exudate concentrations (10-4 M) re-mobilizes only a very small part of the americium fixed on the solid phase. The desorption of 241Am corresponds to a solid/liquid coefficient of partition (Kd) of about 105 L.kg-1. A significant addition of glucose induces an important dissolution of soil carbonates by the indirect action of microorganisms, but does not significantly favor the 241Am remobilization. On the other hand, the presence of strong citrate concentrations (≥ 10-2 M) allows 300 to 10000 time greater re-mobilizations by the complexing of 241Am released after the dissolution of the carrying phases. Finally, the colloidal transport of 241Am has been systematically observed in a limited but significant extend and

  11. An evaluation of the VM/VF ratio to standard UO2 and MOX fuel with 4,5% enrichment and 1% of americium insertion

    International Nuclear Information System (INIS)

    A growing interest exists in the development of techniques for burning and transmuting minor actinides. Some indicate the possibility of differentiated burnup when studying different VM/VF. The VM/VF ratio, moderator volume/fuel volume, is directly related with the value obtained for the multiplication factor k. There is a VM/VF for which k is maximum, and this is directly related with the fuel composition. This work is a study to find a better value of VM/VF, using the WIMS-D5 code, considering a UO2 fuel and a MOX fuel, with 1% Americium insertion. The following parameters were appraised: spectrum hardening, boron worth, and reactivity temperature coefficients. (author)

  12. Recovery of Americium-241 from lightning rod by the method of chemical treatment; Recuperacion del Americio-241 provenientes de los pararrayos por el metodo de tratamiento quimico

    Energy Technology Data Exchange (ETDEWEB)

    Cruz, W.H., E-mail: wcruz@ipen.gob.pe [Instituto Peruano de Energia Nuclear (GRRA/IPEN), Lima (Peru). Division de Gestion de Residuos Radiactivos

    2013-07-01

    About 95% of the lightning rods installed in the Peruvian territory have set in their structures, pose small amounts of radioactive sources such as Americium-241 ({sup 241}Am), fewer and Radium 226 ({sup 226}Ra) these are alpha emitters and have a half life of 432 years and 1600 years respectively. In this paper describes the recovery of radioactive sources of {sup 241}Am radioactive lightning rods using the conventional chemical treatment method using agents and acids to break down the slides. The {sup 241}Am recovered was as excitation source and alpha particle generator for analysing samples by X Ray Fluorescence, for fixing the stainless steel {sup 241}Am technique was used electrodeposition. (author)

  13. Preliminary application of 241-Americium calcaneus bone mineral density measurement in osteoporosis. Comparison with double X-ray densitometry of the lumber spine

    International Nuclear Information System (INIS)

    Bone mineral density (BMD) of calcaneus in 54 normals, 45 Osteoporosis, 25 suspected osteoporosis and 16 other non-osteoporosis patients, a total of 140 cases were measured by HUAKE (HK-1) 241-Americium BMD absorpmetry, among them 43 were compared with that of lumber spine (L2 - L4) measured by Lunar Corporation's Expert-XL absorpmeter. BMD of normal group of calcaneus was (409.8 +- 79.4) mg/cm2. The BMD were decreased slowly with the increasing age. The BMD of osteoporosis, suspected osteoporosis and non-osteoporosis group were 230.3 +- 62.3, 395.7 +- 57.4 and 363.3 +- 51.9 mg/cm2 respectively. The BMD of osteoporosis group was much lower than that of normal group, and also lower than that of the other two groups, among 26 patients (57.78%) had bone fracture, all was in accordance with the clinical diagnosis of osteoporosis. The BMD of suspected osteoporosis and non-osteoporosis had no significant difference with normal group. The coefficient variation (CV) of BMD in repeated measurement in calcaneus of 4 participants was less than 1.2%. The correlative coefficient (r) between BMD of calcaneus and lumber spine (L2 - L4) group was 0.6824. The correlative coefficient of normal young adult-matched percentage and T value in 2 groups were 0.6863 and 0.6755 respectively, whereas aged-matched percentage, Z value were 0.4614 and 0.5009 respectively. In conclusion 241-Americium calcaneus BMD absorpmetry has the advantage of low price, easy to operate, reliable and valuable in diagnosis osteoporosis. The correlations of calcaneus and lumber spine BMD, normal young adult-matched percentage and T value were rather good

  14. Safe handling of kilogram amounts of fuel-grade plutonium and of gram amounts of plutonium-238, americium-241 and curium-244

    International Nuclear Information System (INIS)

    During the past 10 years about 600 glove-boxes have been installed at the Institute for Transuranium Elements at Karlsruhe. About 80% of these glove-boxes have been designed and equipped for handling 100-g to 1-kg amounts of 239Pu containing 8-12% 240Pu (low-exposure plutonium). A small proportion of the glove-boxes is equipped with additional shielding in the form of lead sheet or lead glass for work with recycled plutonium. In these glove-boxes gram-amounts of 241Am have also been handled for preparation of Al-Am targets using tongs and additional shielding inside the glove-boxes themselves. Water- and lead-shielded glove-boxes equipped with telemanipulators have been installed for routine work with gram-amounts of 241Am, 243Am and 244Cm. A prediction of the expected radiation dose for the personnel is difficult and only valid for a preparation procedure with well-defined preparation steps, owing to the fact that gamma dose-rates depend strongly upon proximity and source seize. Gamma radiation dose measurements during non-routine work for 241Am target preparation showed that handling of gram amounts leads to a rather high irradiation dose for the personnel, despite lead or steel glove-box shielding and shielding within the glove-boxes. A direct glove-hand to americium contact must be avoided. For all glove-handling of materials with gamma radiation an irradiation control of the forearms of the personnel by, for example, thermoluminescence dosimeters is necessary. Routine handling of americium and curium should be executed with master-slave equipment behind neutron and gamma shielding. (author)

  15. Actinide Oxidation State and O/M Ratio in Hypostoichiometric Uranium-Plutonium-Americium U0.750Pu0.246Am0.004O2-x Mixed Oxides.

    Science.gov (United States)

    Vauchy, Romain; Belin, Renaud C; Robisson, Anne-Charlotte; Lebreton, Florent; Aufore, Laurence; Scheinost, Andreas C; Martin, Philippe M

    2016-03-01

    Innovative americium-bearing uranium-plutonium mixed oxides U1-yPuyO2-x are envisioned as nuclear fuel for sodium-cooled fast neutron reactors (SFRs). The oxygen-to-metal (O/M) ratio, directly related to the oxidation state of cations, affects many of the fuel properties. Thus, a thorough knowledge of its variation with the sintering conditions is essential. The aim of this work is to follow the oxidation state of uranium, plutonium, and americium, and so the O/M ratio, in U0.750Pu0.246Am0.004O2-x samples sintered for 4 h at 2023 K in various Ar + 5% H2 + z vpm H2O (z = ∼15, ∼90, and ∼200) gas mixtures. The O/M ratios were determined by gravimetry, XAS, and XRD and evidenced a partial oxidation of the samples at room temperature. Finally, by comparing XANES and EXAFS results to that of a previous study, we demonstrate that the presence of uranium does not influence the interactions between americium and plutonium and that the differences in the O/M ratio between the investigated conditions is controlled by the reduction of plutonium. We also discuss the role of the homogeneity of cation distribution, as determined by EPMA, on the mechanisms involved in the reduction process. PMID:26907589

  16. Americium, plutonium and uranium contamination and speciation in well waters, streams and atomic lakes in the Sarzhal region of the Semipalatinsk Nuclear Test Site, Kazakhstan

    International Nuclear Information System (INIS)

    New data are reported on the concentrations, isotopic composition and speciation of americium, plutonium and uranium in surface and ground waters in the Sarzhal region of the Semipalatinsk Test Site, and an adjacent area including the settlement of Sarzhal. The data relate to filtered water and suspended particulate from (a) streams originating in the Degelen Mountains, (b) the Tel'kem 1 and Tel'kem 2 atomic craters, and (c) wells on farms located within the study area and at Sarzhal. The measurements show that 241Am, 239,240Pu and 238U concentrations in well waters within the study area are in the range 0.04-87 mBq dm-3, 0.7-99 mBq dm-3, and 74-213 mBq dm-3, respectively, and for 241Am and 239,240Pu are elevated above the levels expected solely on the basis of global fallout. Concentrations in streams sourced in the Degelen Mountains are similar, while concentrations in the two water-filled atomic craters are somewhat higher. Suspended particulate concentrations in well waters vary considerably, though median values are very low, at 0.01 mBq dm-3, 0.08 mBq dm-3 and 0.32 mBq dm-3 for 241Am, 239,240Pu and 238U, respectively. The 235U/238U isotopic ratio in almost all well and stream waters is slightly elevated above the 'best estimate' value for natural uranium worldwide, suggesting that some of the uranium in these waters is of test-site provenance. Redox analysis shows that on average most of the plutonium present in the microfiltered fraction of these waters is in a chemically reduced form (mean 69%; 95% confidence interval 53-85%). In the case of the atomic craters, the proportion is even higher. As expected, all of the americium present appears to be in a reduced form. Calculations suggest that annual committed effective doses to individual adults arising from the daily ingestion of these well waters are in the range 11-42 μSv (mean 21 μSv). Presently, the ground water feeding these wells would not appear to be contaminated with radioactivity from past

  17. Human bones obtained from routine joint replacement surgery as a tool for studies of plutonium, americium and 90Sr body-burden in general public

    International Nuclear Information System (INIS)

    The paper presents a new sampling method for studying in-body radioactive contamination by bone-seeking radionuclides such as 90Sr, 239+240Pu, 238Pu, 241Am and selected gamma-emitters, in human bones. The presented results were obtained for samples retrieved from routine surgeries, namely knee or hip joints replacements with implants, performed on individuals from Southern Poland. This allowed to collect representative sets of general public samples. The applied analytical radiochemical procedure for bone matrix is described in details. Due to low concentrations of 238Pu the ratio of Pu isotopes which might be used for Pu source identification is obtained only as upper limits other then global fallout (for example Chernobyl) origin of Pu. Calculated concentrations of radioisotopes are comparable to the existing data from post-mortem studies on human bones retrieved from autopsy or exhumations. Human bones removed during knee or hip joint surgery provide a simple and ethical way for obtaining samples for plutonium, americium and 90Sr in-body contamination studies in general public. - Highlights: → Surgery for joint replacement as novel sampling method for studying in-body radioactive contamination. → Proposed way of sampling is not causing ethic doubts. → It is a convenient way of collecting human bone samples from global population. → The applied analytical radiochemical procedure for bone matrix is described in details. → The opposite patient age correlations trends were found for 90Sr (negative) and Pu, Am (positive).

  18. The estimation of reactions of hematopoietic systems of organisms to the effect, caused by americium and plutonium, of nuclear industry workers

    Energy Technology Data Exchange (ETDEWEB)

    Gasteva, G. N.; Ivanova, T. A.; Gordeeva, A. A.; Suvorova, L. A.; Molokanov, A. A.; Badine, I.

    2004-07-01

    Object of research are the workers having in an organism radioactive substance (Am-241 and Pu-239). The purpose of work was the estimation of reaction hemopoietic systems of an organism on influence of americium and plutonium at workers of the nuclear industry. At the surveyed contingent of persons the determined effects caused by total influence Am-241 and Pu-239 are ascertained; chronic radiation disease with development, besides diffusive a pneumoscleoris and a chronic toxic-chemical radiating bronchitis, reactions of system of blood, jet hepatopathy which frequency accrued with increase doses loadings and essentially did not depend on age. In peripheral blood on the foreground jet changes act: hyperglobulia, the tendency to neutrophilus leukocytosis, monocytosis, increase ESR, decrease (reduction ?/G of factor reflecting weight and processing of defeat bronchus and pulmonary of system. Stable downstroke in number thrombocytes and reticulocytes in peripheral blood, their direct dependence on a doze of an irradiation, reflect hypoplastic a background hemogenesis, caused by long influence incorporatedin a bone and a bone brain of radioactive substances. At cytologic research punctate a bone brain jet changes which are expressed in increase of functional activity erythro-and myelopoiesiscome to light and provide compensatory reaction of peripheral blood. At histologic research of a bone brain and a bone fabric attributes of development atrophic process which is expressed in reduction of volume parenchyma a bone brain (a fatty atrophy) and dysplasia to a bone fabric are observed.

  19. Human bones obtained from routine joint replacement surgery as a tool for studies of plutonium, americium and {sup 90}Sr body-burden in general public

    Energy Technology Data Exchange (ETDEWEB)

    Mietelski, Jerzy W., E-mail: jerzy.mietelski@ifj.edu.pl [Henryk Niewodniczanski Institute of Nuclear Physics, Polish Academy of Sciences, Radzikowskiego 152, 31-342 Cracow (Poland); Golec, Edward B. [Traumatology and Orthopaedic Clinic, 5th Military Clinical Hospital and Polyclinic, Independent Public Healthcare Facility, Wroclawska 1-3, 30-901 Cracow (Poland); Orthopaedic Rehabilitation Department, Chair of Clinical Rehabilitation, Faculty of Motor of the Bronislaw Czech' s Academy of Physical Education, Cracow (Poland); Department of Physical Therapy Basics, Faculty of Physical Therapy, Administration College, Bielsko-Biala (Poland); Tomankiewicz, Ewa [Henryk Niewodniczanski Institute of Nuclear Physics, Polish Academy of Sciences, Radzikowskiego 152, 31-342 Cracow (Poland); Golec, Joanna [Orthopaedic Rehabilitation Department, Chair of Clinical Rehabilitation, Faculty of Motor of the Bronislaw Czech' s Academy of Physical Education, Cracow (Poland); Physical Therapy Department, Institute of Physical Therapy, Faculty of Heath Science, Jagiellonian University, Medical College, Cracow (Poland); Nowak, Sebastian [Traumatology and Orthopaedic Clinic, 5th Military Clinical Hospital and Polyclinic, Independent Public Healthcare Facility, Wroclawska 1-3, 30-901 Cracow (Poland); Orthopaedic Rehabilitation Department, Chair of Clinical Rehabilitation, Faculty of Motor of the Bronislaw Czech' s Academy of Physical Education, Cracow (Poland); Szczygiel, Elzbieta [Physical Therapy Department, Institute of Physical Therapy, Faculty of Heath Science, Jagiellonian University, Medical College, Cracow (Poland); Brudecki, Kamil [Henryk Niewodniczanski Institute of Nuclear Physics, Polish Academy of Sciences, Radzikowskiego 152, 31-342 Cracow (Poland)

    2011-06-15

    The paper presents a new sampling method for studying in-body radioactive contamination by bone-seeking radionuclides such as {sup 90}Sr, {sup 239+240}Pu, {sup 238}Pu, {sup 241}Am and selected gamma-emitters, in human bones. The presented results were obtained for samples retrieved from routine surgeries, namely knee or hip joints replacements with implants, performed on individuals from Southern Poland. This allowed to collect representative sets of general public samples. The applied analytical radiochemical procedure for bone matrix is described in details. Due to low concentrations of {sup 238}Pu the ratio of Pu isotopes which might be used for Pu source identification is obtained only as upper limits other then global fallout (for example Chernobyl) origin of Pu. Calculated concentrations of radioisotopes are comparable to the existing data from post-mortem studies on human bones retrieved from autopsy or exhumations. Human bones removed during knee or hip joint surgery provide a simple and ethical way for obtaining samples for plutonium, americium and {sup 90}Sr in-body contamination studies in general public. - Highlights: > Surgery for joint replacement as novel sampling method for studying in-body radioactive contamination. > Proposed way of sampling is not causing ethic doubts. > It is a convenient way of collecting human bone samples from global population. > The applied analytical radiochemical procedure for bone matrix is described in details. > The opposite patient age correlations trends were found for 90Sr (negative) and Pu, Am (positive).

  20. The recycling of the actinides neptunium, americium and curium in a fast power reactor to reduce the long term activity in a final store

    International Nuclear Information System (INIS)

    The starting point for the considerations and calculations given in this dissertation is the inevitable production of radioactive materials in the use of nuclear energy, which creates a considerable potential danger in a final store for a very long period. As one possibility of alleviating this problem, a concept for recycling the waste actinides neptunium, americium and curium was proposed. The waste actinides are separated in the reprocessing of burnt-up fuel elements and reach a further irradiation circuit. There they pass through the stages 'manufacture of irradiation elements', 'use in a fast power reactor' and reprocessing of irradiation elements' several times. In each irradiation and subsequent storage, about 17% of the waste actinides are removed by fission or by conversion into nuclides which can be reused as fuel, so that during the life of 40 years of the fast recycling reacor, the waste actinides can be reduced in mass by one half. In order to determine this mass reduction effect, a model calculation was developed, which includes the representation of the neutron physics and thermal properties of the reactor core and the storage and reprocessing of the irradiation elements. (orig./RB)

  1. Actinide and lanthanum accumulation by immobilized cells of a citrobacter sp. and application to the decontamination of solutions containing americium and plutonium

    International Nuclear Information System (INIS)

    Phosphatase-mediated metal bioaccumulation by a Citrobacter sp. underlies a bioprocess for the removal of heavy metals from solution, as cell-bound metal phosphate. Deposition of uranyl ion indicated a role in the biotechnological removal of americium and plutonium from wastes generated from the nuclear fuel cycle. Preliminary studies suggested a recalcitrance of tetravalent species of U(IV), Th(IV) and Zr(IV) and, by implication, Pu(IV), probably attributable to the stability of metal-ligand complexes in solution. Trials with the trivalent model, La(III), indicated probable bioaccumulation of Pu(III) and Am(III), which was confirmed by the removal of 241Am by cells immobilized in a cartridge incorporated into a flow supplemented with Am. Pu(V) and Pu(IV) wastes may be treatable via prior reduction to Pu(III), with simultaneous removal of the latter with the co-contaminant Am(III). An oxidative route, to Pu(VI), with desolubilization as HPuO2PO4 was also considered, but experiments using the analogous U(VI) (uranyl ion) demonstrated a greater efficiency of M(III) removal. Initial experiments utilized polyacrylamide gel-immobilized cells. 241Am removal also occurred with Citrobacter sp. immobilized as biofilm on reticulated foam supports, more amenable to large-scale processes

  2. Characterization of americium(III) and lanthanide(III) complexes in mixed solvent extraction systems containing a malonamide and a dialkyl-phosphoric acid

    International Nuclear Information System (INIS)

    In order to further reduce toxicity of nuclear waste, the French Commissariat a l'energie atomique et aux energies alternatives (CEA) is developing processes that allow separation of minor actinides from fission products. The DIAMEX (Diamide extraction) - SANEX (Selective actinide extraction) process is based on a mixture of two organic extractants: a malonamide, the N,N'-dimethyl-N,N'-dioctyl-hexyl-ethoxy-malonamide (DMDOHEMA) and a dialkyl-phosphoric acid, the di(2-ethylhexyl)phosphoric acid (HDEHP), dissolved in an alkane. The mechanisms of its extraction process are still not completely understood. Various complementary analytical techniques were used to identify and characterize americium(III) and lanthanide(III) metallic complexes formed in the organic phase after solvent extraction (UV-Visible, Infrared, NMR and Time Resolved Laser-Induced Fluorescence spectroscopy, as well as Electro-spray Ionization Mass Spectrometry). These speciation studies were performed under a variety of experimental conditions (influence of the extractants concentration, acidity of the aqueous phase..) and mixed species including the two extractants were observed. (authors)

  3. Extraction and chromatographic separation and concentration of plutonium and americium from natural matrices. Author-review of dissertation submitted for fulfillment of the scientific degree 'Philosophiae doctor' (PhD.)

    International Nuclear Information System (INIS)

    We followed the optimization of separation progress of americium (241Am) from environmental samples - soil from surroundings nuclear power plant Jaslovske Bohunice, in our work. Selection and optimization of separation progresses had to verify the condition for preparation of samples on spectral measurement with coprecipitation of americium or plutonium with NdF3 (undesirable presence of calcium, magnesium, lanthanides) and condition of spectral purity (spectral overlapping 228Th, 238Pu, 241Am and 222Rn of energy). Very important step was the realization of existing goal and learn suitable isolation techniques of plutonium. We are choosing technique separation of plutonium base upon amine liquid extraction, for a digest consider qualitative quantitative factor of separation. Extraction reagent has been Aliquat-336, which extracts nitric complex of plutonium [Pu(NO3)62-] from 7-8 M solution HNO3. Use method separate off quantitative the plutonium, thorium and uranium from americium. Background sample formed the sample of soil from surroundings Velke Kostolany. Real samples were sampling from surroundings of pollute river Dudvah. Average value mass activities of 239,240Pu in the background sample had value 0.28 ± 0.10 Bq · kg-1. Value mass activities of 239,240Pu in sample from surroundings river Dudvah were in the range (0,6 - 39.4) Bq · kg-1. Methodical side separation of americium we step by step by using ion exchange methods, liquid extraction with extraction reagent TOPO, or combination of them and extraction chromatography with TOPO. We find out: (a) on exchange procedure are suitable on obtainable basis extract tracer of radionuclide, also is very up to time. Optimal method was indicate techniques using the formation of rhodanide complex of americium, with following adsorption on stark acidity anionic exchanger (lanthanides were non-absorbing); (b) t liquid extraction formed emulsion, the third phase on the interface of phases. If we treat the molar of

  4. The construction of TRIGA-TRAP and direct high-precision Penning trap mass measurements on rare-earth elements and americium

    Energy Technology Data Exchange (ETDEWEB)

    Ketelaer, Jens

    2010-06-14

    The construction of TRIGA-TRAP and direct high-precision Penning trap mass measurements on rare-earth elements and americium: Nuclear masses are an important quantity to study nuclear structure since they reflect the sum of all nucleonic interactions. Many experimental possibilities exist to precisely measure masses, out of which the Penning trap is the tool to reach the highest precision. Moreover, absolute mass measurements can be performed using carbon, the atomic-mass standard, as a reference. The new double-Penning trap mass spectrometer TRIGA-TRAP has been installed and commissioned within this thesis work, which is the very first experimental setup of this kind located at a nuclear reactor. New technical developments have been carried out such as a reliable non-resonant laser ablation ion source for the production of carbon cluster ions and are still continued, like a non-destructive ion detection technique for single-ion measurements. Neutron-rich fission products will be available by the reactor that are important for nuclear astrophysics, especially the r-process. Prior to the on-line coupling to the reactor, TRIGA-TRAP already performed off-line mass measurements on stable and long-lived isotopes and will continue this program. The main focus within this thesis was on certain rare-earth nuclides in the well-established region of deformation around N {proportional_to} 90. Another field of interest are mass measurements on actinoids to test mass models and to provide direct links to the mass standard. Within this thesis, the mass of {sup 241}Am could be measured directly for the first time. (orig.)

  5. 6,6 '-bis (5,5,8,8-tetramethyl-5,6,7,8-tetra-hydro-benzo 1,2,4 triazine-3-yl) 2,2 ' bipyridine, an effective extracting agent for the separation of americium(III) and curium(III) from the lanthanides

    International Nuclear Information System (INIS)

    The extraction of americium(III), curium(III), and the lanthanides(III) from nitric acid by 6,6'- bis (5,5,8,8-tetramethyl-5,6,7,8-tetra-hydro-benzo[1,2,4]triazine-3-yl)-[2,2'] bipyridine (CyMe4-BTBP) has been studied. Since the extraction kinetics were slow, N,N'-dimethyl-N,N'-di-octyl-2-(2-hexyl-oxy-ethyl)malonamide (DMDOHEMA) was added as a phase transfer reagent. With a mixture of 0.01 M CyMe4-BTBP + 0.25 M DMDOHEMA in n -octanol, extraction equilibrium was reached within 5 min of mixing. At a nitric acid concentration of 1 M, an americium(III) distribution ratio of approx. 10 was achieved. Americium(III)/lanthanide(III) separation factors between 50 (dysprosium) and 1500 (lanthanum) were obtained. Whereas americium(III) and curium(III) were extracted as di-solvates, the stoichiometries of the lanthanide(III) complexes were not identified unambiguously, owing to the presence of DMDOHEMA. In the absence of DMDOHEMA, both americium(III) and europium(III) were extracted as di-solvates. Back-extraction with 0.1 M nitric acid was thermodynamically possible but rather slow. Using a buffered glycolate solution of pH=4, an americium(III) distribution ratio of 0.01 was obtained within 5 min of mixing. There was no evidence of degradation of the extractant, for example, the extraction performance of CyMe4-BTBP during hydrolysis with 1 M nitric acid did not change over a two month contact. (authors)

  6. Thermodynamic parameters of MeO2+ + H+ reversible MeO22+ + 1/2 H2 reaction for americium and neptunium ions in solution of potassium phosphotungstates

    International Nuclear Information System (INIS)

    Formal oxidation potentials of MeO22+-MeO2+ pair are measured for americium and neptunium ions in solutions of potassium phosphotungstates in 23-51 deg C temperature range at solution pH values equal to 1.0 and 4.0 by differential coulopotentiometric and potentiometric methods. Based on the data obtained Gibbs energy change values; enthalpies and enthropies for MeO2+ + H+ ↔ MeO22+ + 1/2H2 reaction are calculated

  7. Update of JAEA-TDB. Additional selection of thermodynamic data for solid and gaseous phases on nickel, selenium, zirconium, technetium, thorium, uranium, neptunium plutonium and americium, update of thermodynamic data on iodine, and some modifications

    International Nuclear Information System (INIS)

    We additionally selected thermodynamic data for solid and gaseous phases of nickel, selenium, zirconium, technetium, thorium, uranium, neptunium, plutonium and americium to our thermodynamic database JAEA-TDB for geological disposal of radioactive waste of high-level and TRU wastes. We thermodynamically obtained equilibrium constant from addition and subtraction of Gibbs free energy of formation on nickel, selenium, zirconium, technetium, thorium, uranium, neptunium plutonium and americium, which were selected in the Thermochemical Database Project by the Nuclear Energy Agency in the Organisation for Economic Co-operation and Development. Furthermore, we collected and updated thermodynamic data on iodine, changed master species of technetium(IV), and added thermodynamic data on selenium due to improving reliability of the thermodynamic database. We prepared text files of the updated thermodynamic database (JAEA-TDB) for geochemical calculation programs of PHREEQC, EQ3/6 and Geochemist's Workbench. These text files are contained in the attached CD-ROM and will be available on our Website (http://migrationdb.jaea.go.jp/). (author)

  8. Impact of the cation distribution homogeneity on the americium oxidation state in the U{sub 0.54}Pu{sub 0.45}Am{sub 0.01}O{sub 2−x} mixed oxide

    Energy Technology Data Exchange (ETDEWEB)

    Vauchy, Romain [CEA, DEN, DEC, Centre d’études nucléaires de Cadarache, Saint Paul Lez Durance 13108 (France); Robisson, Anne-Charlotte, E-mail: anne-charlotte.robisson@cea.fr [CEA, DEN, DEC, Centre d’études nucléaires de Cadarache, Saint Paul Lez Durance 13108 (France); Martin, Philippe M.; Belin, Renaud C.; Aufore, Laurence [CEA, DEN, DEC, Centre d’études nucléaires de Cadarache, Saint Paul Lez Durance 13108 (France); Scheinost, Andreas C. [Helmholtz Zentrum Dresden-Rossendorf (HZDR), Institute of Radiochemistry, P.O. Box 510119, 01314 Dresden, Germany and Rossendorf Beamline at ESRF, BP 220, F-38043 Grenoble (France); Hodaj, Fiqiri [Science et Ingénierie des Matériaux et Procédés (SIMaP, associé au CNRS UMR 5266 – UJF/INP-Grenoble), Domaine Universitaire, 1130 rue de la piscine, BP 75, 38402 Saint Martin d’Hères (France)

    2015-01-15

    The impact of the cation distribution homogeneity of the U{sub 0.54}Pu{sub 0.45}Am{sub 0.01}O{sub 2−x} mixed oxide on the americium oxidation state was studied by coupling X-ray diffraction (XRD), electron probe micro analysis (EPMA) and X-ray absorption spectroscopy (XAS). Oxygen-hypostoichiometric Am-bearing uranium–plutonium mixed oxide pellets were fabricated by two different co-milling based processes in order to obtain different cation distribution homogeneities. The americium was generated from β{sup −} decay of {sup 241}Pu. The XRD analysis of the obtained compounds did not reveal any structural difference between the samples. EPMA, however, revealed a high homogeneity in the cation distribution for one sample, and substantial heterogeneity of the U–Pu (so Am) distribution for the other. The difference in cation distribution was linked to a difference in Am chemistry as investigated by XAS, with Am being present at mixed +III/+IV oxidation state in the heterogeneous compound, whereas only Am(IV) was observed in the homogeneous compound. Previously reported discrepancies on Am oxidation states can hence be explained by cation distribution homogeneity effects.

  9. Impact of the cation distribution homogeneity on the americium oxidation state in the U0.54Pu0.45Am0.01O2-x mixed oxide

    Science.gov (United States)

    Vauchy, Romain; Robisson, Anne-Charlotte; Martin, Philippe M.; Belin, Renaud C.; Aufore, Laurence; Scheinost, Andreas C.; Hodaj, Fiqiri

    2015-01-01

    The impact of the cation distribution homogeneity of the U0.54Pu0.45Am0.01O2-x mixed oxide on the americium oxidation state was studied by coupling X-ray diffraction (XRD), electron probe micro analysis (EPMA) and X-ray absorption spectroscopy (XAS). Oxygen-hypostoichiometric Am-bearing uranium-plutonium mixed oxide pellets were fabricated by two different co-milling based processes in order to obtain different cation distribution homogeneities. The americium was generated from β- decay of 241Pu. The XRD analysis of the obtained compounds did not reveal any structural difference between the samples. EPMA, however, revealed a high homogeneity in the cation distribution for one sample, and substantial heterogeneity of the U-Pu (so Am) distribution for the other. The difference in cation distribution was linked to a difference in Am chemistry as investigated by XAS, with Am being present at mixed +III/+IV oxidation state in the heterogeneous compound, whereas only Am(IV) was observed in the homogeneous compound. Previously reported discrepancies on Am oxidation states can hence be explained by cation distribution homogeneity effects.

  10. Fabrication of targets for transmutation of americium : synthesis of inertial matrix by sol-gel method. Procedure study on the infiltration of a radioactive solutions

    International Nuclear Information System (INIS)

    addition a new and unexpected phase formed by the reaction of americium with spinel during the high temperature synthesis process has been identified. This new phase could provide a unique menas to stabilise Am in one particular oxidation state. (Author)

  11. Sorption and diffusion of cobalt, nickel, strontium, iodine, cesium and americium in natural fissure surfaces and drill core cups studied by autoradiography, 3

    International Nuclear Information System (INIS)

    This report summarizes the studies on sorption and diffusion of Cs, Sr, Co, Ni, Am and I in common rocks in Finnish bedrock carried out in laboratory experiments. Samples used in these studies were sections of drill cores containing filled and unfilled natural fracture surfaces and drill cores with a diamond drilled longitudinal cavity in the middle of the sample (drill core cups). Samples originated from the two nuclear power plant sites in Finland: tonalite and mica gneiss from Olkiluoto in Eurajoki and rapakivi granite from Haestholmen in Loviisa. The water used in the experiments was synthetic groundwater spiked at a time with one of the radionuclides: Cs-134, Sr-90, Co-60, Ni-63, Am-241 and I-125. Contact times from one week to one year were used to evaluate time dependence of diffusion. An autoradiographic method was used for determination of the penetration depths and diffusion pathways of elements. For determination of diffusion coefficients a quantitative computerized autoradiographic method was used to get the concentration profiles of the radionuclides in the drill cores. Sorption on natural fracture surfaces was more effective than on freshly drilled core samples. Filling materials on natural fracture surfaces, except calcite, increased sorption. The distribution coefficients for drill core cups were about the same as those for unfilled natural fracture surfaces after a contact time of one week and the sorption tendency of radionuclides was: Ka(Cs) > Ka(Co) > Ka(Am) > Ka(Ni) > Ka(Sr) > Ka(I). Radionuclides were observed to penetrate into fissures of the rock matrix and high-capacity minerals. Strontium was found as far as 35 mm in a filled natural fracture surface sample of rapakivi granite after a contact time of one year. The corresponding values were 3.0 mm for cesium, 2.1 mm for cobalt and 2.6 mm for nickel. For americium no diffusion could be observed (a-values for strontium was 6.6 x 10-16-1.1 x 10-13 m2/s, for cesium 4.7 x 10-16-7.2 x 10-15 m2/s

  12. Separation by sequential chromatography of americium, plutonium and neptunium elements: application to the study of trans-uranian elements migration in a European lacustrine system

    International Nuclear Information System (INIS)

    The nuclear tests carried out in the atmosphere in the Sixties, the accidents and in particular that to the power station of Chernobyl in 1986, were at the origin of the dispersion of a significant quantity of transuranic elements and fission products. The study of a lake system, such that of the Blelham Tarn in Great Britain, presented in this memory, can bring interesting answers to the problems of management of the environment. The determination of the radionuclides in sediment cores made it possible not only to establish the history of the depositions and consequently the origin of the radionuclides, but also to evaluate the various transfers which took place according to the parameters of the site and the properties of the elements. The studied transuranic elements are plutonium 238, 239-240, americium 241 and neptunium 237. Alpha emitting radionuclides, their determination requires complex radiochemical separations. A method was worked out to successively separate the three radioelements by using a same chromatographic column. Cesium 137 is the studied fission product, its determination is done by direct Gamma spectrometry. Lead 210, natural radionuclide, whose atmospheric flow can be supposed constant. makes it possible to obtain a chronology of the various events. The detailed vertical study of sediment cores showed that the accumulation mode of the studied elements is the same one and that the methods of dating converge. The cesium, more mobile than transuranic elements in the atmosphere, was detected in the 1963 and 1986 fallout whereas an activity out of transuranic elements appears only for the 1963 fallout. The activity of the 1963 cesium fallout is of the same order of magnitude as that of 1986. The calculation of the diffusion coefficients of the elements in the sediments shows an increased migration of cesium compared to transuranic elements. An inventory on the whole of the lake made it possible to note that the atmospheric fallout constitute the

  13. Americium behaviour in plastic vessels

    Energy Technology Data Exchange (ETDEWEB)

    Legarda, F.; Herranz, M. [Departamento de Ingenieria Nuclear y Mecanica de Fluidos, Escuela Tecnica Superior de Ingenieria de Bilbao, Universidad del Pais Vasco (UPV/EHU), Alameda de Urquijo s/n, 48013 Bilbao (Spain); Idoeta, R., E-mail: raquel.idoeta@ehu.e [Departamento de Ingenieria Nuclear y Mecanica de Fluidos, Escuela Tecnica Superior de Ingenieria de Bilbao, Universidad del Pais Vasco (UPV/EHU), Alameda de Urquijo s/n, 48013 Bilbao (Spain); Abelairas, A. [Departamento de Ingenieria Nuclear y Mecanica de Fluidos, Escuela Tecnica Superior de Ingenieria de Bilbao, Universidad del Pais Vasco (UPV/EHU), Alameda de Urquijo s/n, 48013 Bilbao (Spain)

    2010-07-15

    The adsorption of {sup 241}Am dissolved in water in different plastic storage vessels was determined. Three different plastics were investigated with natural and distilled waters and the retention of {sup 241}Am by these plastics was studied. The same was done by varying vessel agitation time, vessel agitation speed, surface/volume ratio of water in the vessels and water pH. Adsorptions were measured to be between 0% and 70%. The adsorption of {sup 241}Am is minimized with no water agitation, with PET or PVC plastics, and by water acidification.

  14. Americium behaviour in plastic vessels

    International Nuclear Information System (INIS)

    The adsorption of 241Am dissolved in water in different plastic storage vessels was determined. Three different plastics were investigated with natural and distilled waters and the retention of 241Am by these plastics was studied. The same was done by varying vessel agitation time, vessel agitation speed, surface/volume ratio of water in the vessels and water pH. Adsorptions were measured to be between 0% and 70%. The adsorption of 241Am is minimized with no water agitation, with PET or PVC plastics, and by water acidification.

  15. EURADOS action for determination of americium in skull measures in vivo and Monte Carlo simulation; Accion EURADOS para la determinacion de americio en craneo mediante medidas in-vivo y simulacion Monte Carlo

    Energy Technology Data Exchange (ETDEWEB)

    Lopez Ponte, M. A.; Navarro Amaro, J. F.; Perez Lopez, B.; Navarro Bravo, T.; Nogueira, P.; Vrba, T.

    2013-07-01

    From the Group of WG7 internal dosimetry of the EURADOS Organization (European Radiation Dosimetry group, e.V.) which It coordinates CIEMAT, international action for the vivo measurement of americium has been conducted in three mannequins type skull with detectors of Germanium by gamma spectrometry and simulation by Monte Carlo methods. Such action has been raised as two separate exercises, with the participation of institutions in Europe, America and Asia. Other actions similar precede this vivo intercomparison of measurement and modeling Monte Carlo1. The preliminary results and associated findings are presented in this work. The laboratory of the body radioactivity (CRC) of service counter of dosimetry staff internal (DPI) of the CIEMAT, it has been one of the participants in vivo measures exercise. On the other hand part, the Group of numerical dosimetry of CIEMAT is participant of the Monte Carlo2 simulation exercise. (Author)

  16. Critical and shielding parametric studies with the Monte Carlo code TRIPOLI to identify the key points to take into account during the transportation of blanket assemblies with high ratio of americium

    International Nuclear Information System (INIS)

    In the framework of French research program on Generation IV sodium cooled fast reactor, one possible option consists in burning minor actinides in this kind of Advanced Sodium Technological Reactor. Two types of transmutation mode are studied in the world : the homogeneous mode of transmutation where actinides are scattered with very low enrichment ratio in fissile assemblies and the heterogeneous mode where fissile core is surrounded by blanket assemblies filled with minor actinides with ratio of incorporated actinides up to 20%. Depending on which element is considered to be burnt and on its content, these minor actinides contents imply constraints on assemblies' transportation between Nuclear Power Plants and fuel cycle facilities. In this study, we present some academic studies in order to identify some key constraints linked to the residual power and neutron/gamma load of such kind of blanket assemblies. To simplify the approach, we considered a modeling of a 'model cask' dedicated to the transportation of a unique irradiated blanket assembly loaded with 20% of Americium and basically inspired from an existent cask designed initially for the damaged fissile Superphenix assembly transport. Thermal calculations performed with EDF-SYRTHES code have shown that due to thermal limitations on cladding temperature, the decay time to be considered before transportation is 20 years. This study is based on explicit 3D representations of the cask and the contained blanket assembly with the Monte Carlo code TRIPOLI/JEFF3.1.1 library and concludes that after such a decay time, the transportation of a unique Americium radial blanket is feasible only if the design of our model cask is modified in order to comply with the dose limitation criterion. (author)

  17. Thermodynamics of extraction of plutonium(IV) and americium(III) in polyethylene glycol (PEG) and (NH4)2SO4 based aqueous biphasic system (ABS) using 18-crown-6

    International Nuclear Information System (INIS)

    Extraction of plutonium(IV) and americium(III) using PEG-2000/(NH4)2SO4 (40% w/w of each) aqueous biphasic system (ABS) with 18-crown-6 (18-C-6) was studied at four different temperatures in the range of 288 to 318 K. The species extracted are identified to be [Pu.2(18-C-6)](SO4)2 and [Am.2(18-C-6)](SO4)1.5 for Pu(IV) and Am(III), respectively, by the slope ratio method. The thermodynamic parameters evaluated at 298 K by the temperature coefficient approach show that the reaction is favoured by decrease of enthalpy and counteracted by decrease in entropy in the case of Pu(IV) as well as Am(III). The large decrease in the enthalpy observed indicates that there is direct bonding of crown ether to the central metal atom i.e. the formation of inner sphere complex for both Pu(IV) and Am(III) and is similar to that reported previously for Pu(VI). The order of equilibrium constant K and ΔG value is Pu(IV) > Pu(VI) > Am(III) and this is in accordance with the axial charge experienced by the incoming ligand. (orig.)

  18. Use of radioactive methods for determination of uranium, neptunium, plutonium, americium and curium isotopes in waste radioactive; Utilizacao de metodos radioanaliticos para determinacao de isotopos de uranio, netunio, plutonio, americio e curio em rejeitos radioativos

    Energy Technology Data Exchange (ETDEWEB)

    Geraldo, Bianca

    2012-07-01

    Activated charcoal is a common type of radioactive waste that contains high concentrations of fission and activation products. The management of this waste includes its characterization aiming the determination and quantification of the specific radionuclides including those known as Difficult-to-Measure Radionuclides (RDM). The analysis of the RDM's generally involves complex radiochemical analysis for purification and separation of the radionuclides, which are expensive and time-consuming. The objective of this work was to define a methodology for sequential analysis of the isotopes of uranium, neptunium, plutonium, americium and curium present in a type of radioactive waste, evaluating chemical yield, analysis of time spent, amount of secondary waste generated and cost. Three methodologies were compared and validated that employ ion exchange (TI+EC), extraction chromatography (EC) and extraction with polymers (ECP). The waste chosen was the activated charcoal from the purification system of primary circuit water cooling the reactor IEA-R1. The charcoal samples were dissolved by acid digestion followed by purification and separation of isotopes with ion exchange resins, extraction and chromatographic extraction polymers. Isotopes were analyzed on an alpha spectrometer, equipped with surface barrier detectors. The chemical yields were satisfactory for the methods TI+EC and EC. ECP method was comparable with those methods only for uranium. Statistical analysis as well the analysis of time spent, amount of secondary waste generated and cost revealed that EC method is the most effective for identifying and quantifying U, Np, Pu, Am and Cm present in charcoal. (author)

  19. Solubility and speciation studies of waste radionuclides pertinent to geologic disposal at Yucca Mountain: Results on neptunium, plutonium and americium in J-13 groundwater; Letter report (R707): Reporting period, October 1, 1985--September 30, 1987

    Energy Technology Data Exchange (ETDEWEB)

    Nitsche, H.; Standifer, E.M.; Lee, S.C.; Gatti, R.C.; Tucker, D.B.

    1988-01-01

    We have studied the solubilities of neptunium, plutonium, and americium in J-13 groundwater from Yucca Mountain (Nevada) at three temperatures and hydrogen ion concentrations. They are 25{degree}, 60{degree}C, and 90{degree}C and pH 5.9, 7.0, and 8.5. The results for 25{degree}C are from a study which we did during FY 1984. We included these previous results in the tables to give more information on the solubility temperature dependence; they were, however, done at only one pH (7.0). The solubilities were studied from oversaturation. The nuclides were added at the beginning of each experiment as NpO{sub 2}{sup +}, Pu{sup 4+}, and Am{sup 3+}. The neptunium solubility decreased with increasing temperature and with increasing pH. The soluble neptunium did not change oxidation state at steady state. The pentavalent neptunium was increasingly complexed by carbonate with increasing pH. All solids were crystalline and contained carbonate, except the solid formed at 90{degree}C and pH 5.9. We identified this solid as crystalline Np{sub 2}P{sub 5}. The 25{degree}C, pH 7 solid was Na{sub 3}NpO{sub 2}(CO{sub 3}){sub 2} {center_dot} nH{sub 2}O. Plutonium concentrations decreased with increasing temperature and showed no trend with pH. Pu(V) and Pu(VI) were the dominant oxidation states in the supernatant solution; as the amount of Pu(V) increased with pH, Pu(VI) decreed. The steady-state solids were mostly amorphous, although some contained a crystalline component. They contained Pu(IV) polymer and unknown carbonates.

  20. The proliferation potential of neptunium and americium

    International Nuclear Information System (INIS)

    It is recognized that some trans-uranic elements other than plutonium, in particular Np and Am, if will be available in sufficient quantities, could be used for nuclear explosive devices. The spent fuel has been accumulating in number of nuclear power plant and operation of large scale commercial reprocessing plants. However, these materials are not covered by the definition of special fissionable material in the Agency Statute. At the time when the Statute was adopted, the availability of meaningful quantities of separated Np and Am was remote and they were not included in the definition of special fissionable material. Then, IAEA Board decided a measure for control of Np and Am on September 1999. This report contains the control method and the characteristic of Np and Am for using domestic nuclear industries, and it can be useful for understanding how to report and account of Np and Am. (author)

  1. The proliferation potential of neptunium and americium

    Energy Technology Data Exchange (ETDEWEB)

    An, J. S.; Shin, J. S.; Kim, J. S.; Kwack, E. H.; Kim, B. K

    2000-05-01

    It is recognized that some trans-uranic elements other than plutonium, in particular Np and Am, if will be available in sufficient quantities, could be used for nuclear explosive devices. The spent fuel has been accumulating in number of nuclear power plant and operation of large scale commercial reprocessing plants. However, these materials are not covered by the definition of special fissionable material in the Agency Statute. At the time when the Statute was adopted, the availability of meaningful quantities of separated Np and Am was remote and they were not included in the definition of special fissionable material. Then, IAEA Board decided a measure for control of Np and Am on September 1999. This report contains the control method and the characteristic of Np and Am for using domestic nuclear industries, and it can be useful for understanding how to report and account of Np and Am. (author)

  2. Evaluation of neutron data for americium-241

    Energy Technology Data Exchange (ETDEWEB)

    Maslov, V.M.; Sukhovitskij, E.Sh.; Porodzinskij, Yu.V.; Klepatskij, A.B.; Morogovskij, G.B. [Radiation Physics and Chemistry Problems Inst., Minsk-Sosny (Belarus)

    1997-03-01

    The evaluation of neutron data for {sup 241}Am is made in the energy region from 10{sup -5} eV up to 20 MeV. The results of the evaluation are compiled in the ENDF/B-VI format. This work is performed under the Project Agreement CIS-03-95 with the International Science and Technology Center (Moscow). The Financing Party for the Project is Japan. The evaluation was requested by Y. Kikuchi (JAERI). (author). 60 refs.

  3. Recovery of americium by extraction chromatographic technique

    International Nuclear Information System (INIS)

    Acidic liquid waste (raffinate) was generated during continuous solvent extraction runs carried out in a countercurrent mode for the extraction of U(VI) and Pu(IV) by tri-isoamyl phosphate (TiAP) using an ejector mixer-settler. It contained Am (III) with a concentration of about 0.3 mg/mL in 1.6 M HNO3, over a volume of 2 liters. The objective of the present study was to develop a procedure for the recovery of Am from acidic solution and concentrate in a small volume. The compound, octyl(phenyl)-N,N-diisobutylcarbamoylmethylphosphine oxide (CMPO) was studied in detail for the extraction of actinides. Extraction chromatography is an important separation technique and is used for the recovery of various radionuclides

  4. Migration study of americium in porous medium

    International Nuclear Information System (INIS)

    Migration experiments of 241Am3+ had been performed by a column system, to investigate migration behavior of 241Am through a column packed porous sedimentary materials: a coastal sandy soil and a reddish soil. Most 241Am loaded into the column packed the reddish soil sorbed on the influent edge of the column. In the case of the sandy soil, however, considerable amount of 241Am was passed through the column. This shows that there is colloidal 241Am species which may move without effective interaction with the sandy soil. Such a migration behavior of colloidal 241Am in the sandy soil column could be evaluated by a sorption model based on filtration theory. Sorption mechanisms of 241Am on the sedimentary materials were examined by a chemical extraction method, for 241Am sorbed on the sandy soil and the reddish soil at any sections in the column. The 241Am sorbed on the reddish soil was mainly controlled by a reversible ion exchange reaction. On the other hand, the 241Am sorbed on the sandy soil ws controlled by irreversible reactions, such as the selective chemical sorptions onto Fe and Mn oxyhydroxide/oxide. The experimental results support that the migration of 241Am in the reddish soil layer can be estimated by using the Kd, whereas that in the sandy soil can not be explained by the Kd concept. (author)

  5. Fabrication of targets for transmutation of americium : synthesis of inertial matrix by sol-gel method. Procedure study on the infiltration of a radioactive solutions; Fabricacion de blancos para la transmutacion de americio: sintesis de matrices inertes por el metodo sol-gel. Estudio del procedimiento de infiltracion de disoluciones radiactivas

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez Carretero, A. [Universidad Complutense de Madrid (Spain)

    2002-07-01

    made. In addition a new and unexpected phase formed by the reaction of americium with spinel during the high temperature synthesis process has been identified. This new phase could provide a unique menas to stabilise Am in one particular oxidation state. (Author)

  6. Plutonium and americium behavior in coral atoll environments

    International Nuclear Information System (INIS)

    Inventories of 239+240Pu and 241Am greatly in excess of global fallout levels persist in the benthic environments of Bikini and Enewetak Atolls. Quantities of 239+240Pu and lesser amounts of 241Am are continuously mobilizing from these sedimentary reservoirs. The amount of 239+240Pu mobilized to solution at any time represents 0.08 to 0.09% of the sediment inventories to a depth of 16 cm. The mobilized 239+240Pu has solute-like characteristics and different valence states coexist in solution - the largest fraction of the soluble plutonium is in an oxidized form (+V,VI). The adsorption of plutonium to sediments is not completely reversible because of changes that occur in the relative amounts of the mixed oxidation states in solution with time. Further, any characteristics of 239+240Pu described at one location may not necessarily be relevant in describing its behavior elsewhere following mobilization and migration. The relative amounts of 241Am to 239+240Pu in the sedimentary deposits at Enewetak and Bikini may be altered in future years because of mobilization and radiological decay. Mobilization of 239+240Pu is not a process unique to these atolls, and quantities in solution derived from sedimentary deposits can be found at other global sites. These studies in the equatorial Pacific have significance in assessing the long-term behavior of the transuranics in any marine environment. 22 references, 1 figure, 13 tables

  7. Complex formation of americium (III) with humic acid

    International Nuclear Information System (INIS)

    The presence of humic substances in natural waters will modify the migration behavior of actinides in the geosphere due to the strong reaction properties of these ligands with actinides. Therefore, the possible reactions of humic acid with actinides have been studied widely in recent years. The complex formation of Am (III) with humic acid is studied with solvent extraction technique in this paper. The experiments are performed in the pH range from 4.0 to 8.0 in 0.1 M NaClO4 solution at ambient temperature. Experimental results show that the complex formation constants of Am (III) with humic acid are varied with the variation of pH value in solution. 1:2 complex is obtained in the experiments and the complex formation constants determined at each pH are: lgβ1=6.56±0.05, lgβ2=10.77±0.31 at pH=4.0; lgβ1=7.94±0.11, lgβ2=11.80±0.21 at pH=5.0; lgβ1=10.74±0.28, lgβ2=12.88±0.49 at pH=6.0; lgβ1=12.85±0.30, lgβ2=14.80±0.62 at pH=7.0; lgβ1=14.88±0.48, lgβ2=15.65±0.69 at pH=8.0, respectively. The dependence of the complex of the complex formation constant on pH is: lgβ1=2.16(±0.98)pH-2.34(±1.03), lgβ2=1.28(±1.04)pH+5.52(±1.21), respectively. (author)

  8. Europium (III) and americium (III) stability constants with humic acid

    International Nuclear Information System (INIS)

    The stability constants for tracer concentrations of Eu(III) and Am(III) complexes with a humic acid extracted from a lake-bottom sediment were measured using a solvent extraction system. The organic extractant was di(2-ethylhexyl)-phosphoric acid in toluene while the humate aqueous phase had a constant ionic strength of 0.1 M (NaClO4). Aqueous humic acid concentrations were monitored by measuring uv-visible absorbances at approx.= 380 nm. The total carboxylate capacity of the humic acid was determined by direct potentiometric titration to be 3.86 +- 0.03 meq/g. The humic acid displayed typical characteristics of a polyelectrolyte - the apparent pKsub(a), as well as the calculated metal ion stability constants increased as the degree of ionization (α) increased. The binding data required a fit of two stability constants, β1 and β2, such that for Eu, log β1 = 8.86 α + 4.39, log β2 = 3.55 α + 11.06 while for Am, log β1 = 10.58 α + 3.84, log β2 = 5.32 α + 10.42. With hydroxide, carbonate, and humate as competing ligands, the humate complex associated with the β1 constant is calculated to be the dominant species for the trivalent actinides and lanthanides under conditions present in natural waters. (orig.)

  9. complex formation of americium (III) with humic acid

    International Nuclear Information System (INIS)

    The presence of humic substances in natural waters will modify the migration behavior of actinides in the geosphere due to the strong reaction properties of these ligands with actinides. Therefore, the possible reactions of humic acid with actinides have been studied widely in recent years. The complex formation of Am(III) with humic acid is studied with solvent extraction technique. The experiments are performed in the pH range from 4.0 to 8.0 in 0.1 mol/kg NaClO4 solution at ambient temperature. Experimental results show that the complex formation constants of Am(III) with humic acid are varied with the variation of pH value in solution. 1:2 complex is obtained in the experiments and the complex formation constants determined at each pH are: lgβ1 = 6.56 +- 0.05, lgβ2 = 10.77 +- 0.31 at pH 4.0. lgβ1 = 7.94 +- 0.11, lgβ2 = 11.80 +- 0.21 at pH = 5.0. lgβ1 = 10.74 +- 0.28, lgβ2 = 12.88 +- 0.49 at pH = 6.0. lgβ1 = 12.85 +- 0.30, lgβ2 = 14.80 +- 0.62 at pH = 7.0. lgβ1 = 14.88 +- 0.48, lgβ2 = 15.65 +- 0.69 at pH = 8.0, respectively. The dependence of the complex formation constant on pH is: lgβ1 = 2.16 (+-0.98)pH-2.34(+-0.93),lgβ2 1.28(+-1.04)pH+5.52(+-1.21), respectively

  10. Further Studies of Plutonium and Americium at Thule, Greenland

    DEFF Research Database (Denmark)

    Aarkrog, Asker; Dahlgaard, Henning; Nilsson, Karen Kristina;

    1984-01-01

    Eleven years after the accidental loss of nuclear weapons in 1968, the fourth scientific expedition to Thule occurred. The estimated inventory of 1 TBq 239,240Pu in the marine sediments was unchanged when compared with the estimate based on the 1974 data. Plutonium from the accident had moved...

  11. 'Americium(III)/trivalent lanthanides' separation using organothiophosphinic acids

    International Nuclear Information System (INIS)

    The present paper describes the extraction of neodymium and other lanthanides by saponified Cyanex 301 acid. The saponification of commercial Cyanex 301 acid favoured the extraction of macro concentrations of neodymium from sodium nitrate aqueous solutions (pHeq ∼ 4). The amount of lanthanide extracted in the organic phase always reached the third of the initial concentration of saponified Cyanex 301 acid, which assumed a cation exchange mechanism to occur during the extraction. No nitrate anion took part in the complex formation. This paper also compares the abilities of purified Cyanex 301, Cyanex 302 and Cyanex 272 acids to extract and separate 241Am(III) from 152Eu(III). Very high separation factors S.F.Am/Eu were observed in the case of purified Cyanex 301 acid. Finally some studies are presented herein using tri-n-butylphosphate (TBP) as a synergistic extractant with Cyanex 301 acid to separate actinides from trivalent lanthanide. (author)

  12. `Americium(III)/trivalent lanthanides` separation using organothiophosphinic acids

    Energy Technology Data Exchange (ETDEWEB)

    Hill, C.; Madic, C.; Baron, P. [CEA Marcoule, 30 - Bagnols-sur-Ceze (France); Ozawa, Masaki; Tanaka, Yasumasa

    1997-12-31

    The present paper describes the extraction of neodymium and other lanthanides by saponified Cyanex 301 acid. The saponification of commercial Cyanex 301 acid favoured the extraction of macro concentrations of neodymium from sodium nitrate aqueous solutions (pH{sub eq} {approx} 4). The amount of lanthanide extracted in the organic phase always reached the third of the initial concentration of saponified Cyanex 301 acid, which assumed a cation exchange mechanism to occur during the extraction. No nitrate anion took part in the complex formation. This paper also compares the abilities of purified Cyanex 301, Cyanex 302 and Cyanex 272 acids to extract and separate {sup 241}Am(III) from {sup 152}Eu(III). Very high separation factors S.F.{sub Am/Eu} were observed in the case of purified Cyanex 301 acid. Finally some studies are presented herein using tri-n-butylphosphate (TBP) as a synergistic extractant with Cyanex 301 acid to separate actinides from trivalent lanthanide. (author)

  13. Preparation of americium targets for nuclear chemistry experiments at DANCE

    International Nuclear Information System (INIS)

    Using 1 gram of 241Am from LANL stocks, the purification steps required to obtain a solution of 241Am from the original material are described. Part of the purified solution was submitted for purity analysis by mass spectrometry, radiochemistry and trace metals analysis. The impurities were expected to be 239Pu and 237Np. A second fraction of this material was used for electroplating three samples onto titanium disks that were suitable for insertion into an instrument package to be placed into the DANCE detector. The purification methods used, the electroplating setup and the solutions to various problems that were encountered in making these targets are discussed. The analytical results are discussed as well as the yields from the electrodeposition process. Comparison of these yields with those from similar experiments utilizing 235U and 243Am are also discussed. (author)

  14. Recovery of neptunium, plutonium, and americium from highly active waste

    International Nuclear Information System (INIS)

    Trialkylphosphine oxides (TRPO) (alkyl is 6c-C8) were chosen as the extractant for the recovery of Np, Pu, and Am from highly active waste (HAW) because of its extraction ability, excellent solvent behavior, high radiolytic stability, and low cost. Process chemistry based on 30 vol % TRPO-kerosene as solvent is presented. Extraction of Am in the presence of macro amounts of neodymium, adjustment of Np valence by electrolytic reduction, selective stripping of actinides from loaded organic phase, and loading capacity of the solvent are included. Process parameters of multistage countercurrent extraction and stripping and the results of experimental verification are given. From HAW with ∼1 M nitric acid concentration, recovery of actinides is higher than 99.9%. The actinides extracted can be stripped out separately into Am, Np-Pu, and U fractions. The behavior of nonactinide HAW constituents, including Tc, is discussed

  15. Property Data for Simulated Americium/Curium Glasses

    International Nuclear Information System (INIS)

    The authors studied the properties of mixed lanthanide-alumino-borosilicate glasses. Fifty-five glasses were designed to augment a previous, Phase I, study by systematically varying the composition of Ln2O3 and the concentrations of Ln2O3, SiO2, B2O3, Al2O3, and SrO in glass. These glasses were designed and fabricated at the Savannah River Technology Center and tested at the Pacific Northwest National Laboratory. The properties measured include the high-temperature viscosity (η) as a function of temperature (T) and the liquidus temperature (TL) of Phase II test glasses

  16. The vapour pressure of americium(III) chloride

    International Nuclear Information System (INIS)

    Based on the method described by Fischer, an ultramicro-size appratus was developed for static determination of the saturation vapour pressure of highly radioactive materials. The apparatus was tested with MgCl2, MnCl2, HoCl3 and ScF3. The vapour pressure curves of MgCl2 and MnCl2 were in good agreement with other publications and thus proved the efficiency of the apparatus in spite of its difficulties of handling. The values measured for HoCl3 and ScF3 differed from those of earlier publications. However, these deviations have been observed before and may be the result of the different measuring principles of static and dynamic methods. For AmCl3, the following vapour pressure equation was established: log psub(Torr)=-(11826/T)+10.7. The thermodynamic parameters of the evaporation process were calculated on this basis, and the values for AmBr3 and PnCl3 were determined by extrapolation. (orig.)

  17. Pressure-induced americium valence fluctuations revealed by electrical resistivity

    Czech Academy of Sciences Publication Activity Database

    Kolomiets, A. V.; Griveau, J.C.; Heathman, S.; Shick, Alexander; Wastin, F.; Faure, P.; Klosek, V.; Genestier, C.; Baclet, N.; Havela, L.

    2008-01-01

    Roč. 82, č. 5 (2008), 57007/1-57007/5. ISSN 0295-5075 R&D Projects: GA MŠk OC 144; GA ČR GA202/07/0644 Grant ostatní: EU(XE) RITA-CT-2006-026176 Institutional research plan: CEZ:AV0Z10100520 Keywords : electrical conductivity * strong electron interactions * electronic structure Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.203, year: 2008

  18. 1976 Hanford americium-exposure incident: accident description

    International Nuclear Information System (INIS)

    An accident is described, involving the explosion of an ion-exchange column containing about 100 g of 241Am. A chemical operator was injured in this accident, receiving acid burns and superficial cuts on the upper part of his body. From 1 to 5 curies of 241Am is estimated to have been deposited on the injured worker and on his clothing

  19. Investigation of the retention and distribution of americium-241 in the baboon and the enhanced removal of americium-241 from the body by diethylenetriaminepentaacetic acid (DTPA)

    International Nuclear Information System (INIS)

    Experiments were performed to study the metabolism and distribution of intravenously administered 241Am in the adult and juvenile baboon; in addition, decorporation therapy using Na3-CaDTPA was performed on selected baboons to assess the efficacy of this drug in removing systemic burdens of 241Am from this primate species. Determination of the kinetics of 241Am was accomplished principally by in vivo methodologies and by radiochemical analysis of 241Am activity of biological material. The use of Na3-CaDTPA as a therapeutic agent for the removal of 241Am from the body proved to be an effective form of treatment in the case of early administration. (U.S.)

  20. An arm phantom for in vivo determination of Americium-241 in bone

    International Nuclear Information System (INIS)

    The focus of this research has been to construct a realistic arm phantom as a calibration tool in estimation of 241Am in the bone. The United States Transuranium Registry (USTR), through its program of whole body donations, continues to provide data on transuranic incorporation in man that would not otherwise be readily available (Norwood 1972; Breitenstein 1981; Swint, et al. 1985). This project uses well-characterized human bones loaned by the USTR for the construction of realistic phantoms for improvement of whole-body counter calibrations. 27 refs., 2 figs., 4 tabs

  1. Biosorption of radionuclide Americium-241 by A. niger spore and hyphae

    International Nuclear Information System (INIS)

    The biosorption of radionuclide 241Am from solution was studied by a. niger spore and hyphae, and the effects of the operational conditions on the treatment were investigated. The results showed the treatment by A. niger spore and hyphae were very efficient. An average of 96% of the total 241Am was removed from 241Am solutions of 5.6-111 MBq/L (C0), with adsorption capacities (W) of 7.2-142.4 MBq/g biomass, 5.2-106.5 MBq/g, respectively. The biosorption equilibrium was achieved within 1 h and the optimum pH value ranged 3-0.1 mol/L HNO3 and 3-2 for spore and hyphae of A. niger, respectively. No significant effects on 241Am biosorption were observed at 15 degree C-45 degree C, or challenged with containing Au3+ or Ag+, even 2000 times above 241Am amount. the index relationship between concentrations and adsorption capacities of 241Am indicated that the 241Am biosorption by A. niger spore and hyphae obey to Freundlich adsorption equation. The adsorption behavior of A. niger spore and hyphae were basically coincident

  2. Americium and plutonium release behavior from irradiated mixed oxide fuel during heating

    Science.gov (United States)

    Sato, I.; Suto, M.; Miwa, S.; Hirosawa, T.; Koyama, S.

    2013-06-01

    The release behavior of Pu and Am was investigated under the reducing atmosphere expected in sodium cooled fast reactor severe accidents. Irradiated Pu and U mixed oxide fuels were heated at maximum temperatures of 2773 K and 3273 K. EPMA, γ-ray spectrometry and α-ray spectrometry for released and residual materials revealed that Pu and Am can be released more easily than U under the reducing atmosphere. The respective release rate coefficients for Pu and Am were obtained as 3.11 × 10-4 min-1 and 1.60 × 10-4 min-1 at 2773 K under the reducing atmosphere with oxygen partial pressure less than 0.02 Pa. Results of thermochemical calculations indicated that the main released chemical forms would likely be PuO for Pu and Am for Am under quite low oxygen partial pressure.

  3. Effectiveness of mixed ligand chelation for the removal of plutonium and americium in the hamster

    International Nuclear Information System (INIS)

    DTPA and the combination of DTPA plus salicylic acid or other benzene derivatives which are ortho-di-substituted with functional groups containing one or more oxygen and/or nitrogen atoms as electron donors, were tested for their ability to remove 239Pu and/or 241Am from hamsters. Mixed ligand chelation of these actinides by combination of DTPA and any one of these compounds did not result in an increased efficacy for the removal of actinides, as has been reported elsewhere

  4. Fabrication of uranium-americium mixed oxide fuels: thermodynamical modeling and materials properties

    International Nuclear Information System (INIS)

    Fuel irradiation in pressurized water reactors lead to the formation of fission products and minor actinides (Np, Am, Cm) which can be transmuted in fast neutrons reactors. In this context, the aim of this work was to study the fabrication conditions of the U1-yAmyO2+x fuels which exhibit particular thermodynamical properties requiring an accurate monitoring of the oxygen potential during the sintering step. For this reason, a thermodynamical model was developed to assess the optimum sintering conditions for these materials. From these calculations, U1-yAmyO2+x (y=0.10; 0.15; 0.20; 0.30) were sintered in two range of atmosphere. In hyper-stoichiometric conditions at low temperature, porous and multiphasic compounds are obtained whereas in reducing conditions at high temperature materials are dense and monophasic. XAFS analyses were performed in order to obtain additional experimental data for the thermodynamical modeling refinement. These characterizations also showed the reduction of Am(+IV) to Am(+III) and the partial oxidation of U(+IV) to U(+V) due to a charge compensation mechanism occurring during the sintering. Finally, taking into account the high - activity of Am, self-irradiation effects were studied for two types of microstructures and two Am contents (10 and 15%). For each composition, a lattice parameter increase was observed without structural change coupled with a macroscopic swelling of the pellet diameter up to 1.2% for the dense compounds and 0.6% for the tailored porosity materials. (author)

  5. Interaction of americium (III) with humic acids and two synthetic analogues

    International Nuclear Information System (INIS)

    In this paper, a recent series of studies on complexation of Am3+ with humic acids and some analogues are summarized and the experimental procedures and method for data analysis applied are presented. The samples are: LBHA(mud-derived humic acid), BHA (humic acid from coastal marine sediments), ALHA (commercial humic acid), SHA (synthetic humic acid), and PMA (poly(maleic) acid). LBHA is the most extensively studied for actinide binding of this group of ligands. Comparison is made of the metal-binding properties of the BHA and ALHA humic acids with those of LBHA to learn the applicability of the results for a particular humic acid, LBHA, to others of different origin. SHA and PMA are often employed in metal-binding and other studies as analogues of natural humic acid. These analogues have a more regular structure and their data may be easier to interpret. Optical spectroscopy, potentiometric titration, and solvent extraction are used in the investigations. The present study supports with qualifications the similarity in actinide binding by humic acids of different origin. It has also indicated that the synthetic humic acid is a suitable analog of natural humic acids for actinide binding studies while PMA more closely mimics a fulvic acid. (N.K.)

  6. Complexation of americium with humic, fulvic and citric acids at high ionic strength

    International Nuclear Information System (INIS)

    The stability constants of the Am3+ complexes of humic, fulvic and citric acids (HA, FA and Cit) were determined as a function of ionic strength (NaCl) using a solvent extraction technique. At a HA degree of ionization of 0.7 for the carboxylate groups, the Am-HA binding constant, log β1, varies from 8.3 at I = 0.2 m to 7.2 at I = 6.0 m. The log β1 of Am-Cit varies from 5.9 at I = 0.3 m to 5.10 at I = 5.0 m. Comparison of the binding constants of Am with HA, FA and Cit shows that, at high ionic strength, log β1 (AmCit) ∼ log β1(AmFA) ∼ {log β1(AmHA) - 1}. Comparison of the values of other metals indicate that the log β1 values for Cit can serve to estimate HA and FA. (orig.)

  7. Complexation of americium(III) with humic acid by cation exchange and solvent extraction

    International Nuclear Information System (INIS)

    Complexation of Am(III) with humic acid was studied at various pHs in 0.1M NaClO4. The stability constants of the Am(III)-humate complexes were determined by a cation-exchange method. The values of logβ1 and logβ2 increased slightly with increases of pH from 4 to 6 and were found to be 6.9 and 11.6, respectively, at a pH of 5. Markedly larger values than these were obtained by a solvent extraction method. This discrepancy was also revealed by summarizing data from several literature sources. It is very likely that this can be ascribed to decreases in either humic acid and/or the extractant from the extraction system due to humate interactions at the aqueous-organic interface. (author)

  8. From Earth to Mars in 15 days with an americium-propelled space ship

    International Nuclear Information System (INIS)

    This digest paper presents the theoretical project of a fission engine for space ship as imagined by Y. Ronen from the Ben-Gourion Univ. (Israel). In this engine, the combustion chamber is covered with metastable 242Am thin sheets. The fission reaction is triggered with a bombardment of neutrons and the fission fragments ionize a gas (hydrogen, for instance) which is overheated and ejected through the engine nozzle. (J.S.)

  9. Chemical behaviour of americium in natural aquatic solutions: Hydrolysis, radiolysis and redox reactions

    International Nuclear Information System (INIS)

    Hydrolysis and redox reactions of the Am(III) and Am(V) ions have been investigated in NaClO4 and NaCl solutions as well as in natural saline groundwaters. The hydrolysis constants of Am(OH)n3-n species and the solubility product of Am(OH)3(s) have been determined in 0.1 M NaClO4, 0.1 M NaCl and 0.6 M NaCl solutions. As observed in concentrated NaCl solutions (> 3 M), the α-radiation induces the radiolytic oxidation of the Cl--ion to produce Cl2, HClO, ClO- and other oxidized species, which result in a strongly oxidizing medium. Consequently Am(III) is oxidized to Am(V). Under these conditions the hydrolysis constants of AmO2(OH)n1-n species and the solubility product are also determined. The α-radiation induced radiolysis reactions in NaCl solution and the subsequent oxidation reaction of Am(III) have been systematically investigated by varying pH, NaCl concentration and specific α-activity. Also included in the investigation are a few selected groundwaters of relatively high salinity from the Gorleben aquifer systems. (orig.)

  10. Effect of solvent on in vitro dissolution: Summary of results for uranium, americium, and cobalt aerosols

    International Nuclear Information System (INIS)

    The revised 10 CFR Part 20 has adopted the ICRP Publication 30 method for calculating the committed effective dose equivalent from intakes of radionuclides. This dosimetry scheme requires knowledge or assumptions about the chemical form of the radionuclide, its particle size, and its known or assumed solubility. The solubility is classified as being either D (relatively soluble), W, or Y (relatively insoluble), depending on whether the material dissolves over periods of days, weeks, or years. Although Nuclear Regulatory Commission licensees may wish to take advantage of material-specific knowledge in order to adjust annual limits on intake and derived air concentrations, relatively few radioactive materials to which workers and the general population may be exposed have been adequately characterized either in terms of physicochemical form or solubility. Experimental measurement of solubility using some type of in vitro dissolution measurement system is therefore needed. However, there is currently no clear consensus regarding the appropriate design of in vitro dissolution systems, particularly when considering the range of different radionuclides to be studied, and the complexity of the biological mechanisms involved in the retention and clearance of inhaled deposited radioactive particles. The purpose of this study was to evaluate the effect of the several solvents on the dissolution of four test aerosols (57Co3O4, 241AmO2, ammonium diuranate [ADU], and U3O8) selected to encompass a variety of chemical and biochemical properties in vivo. The results of this study provide some guidance on the usefulness of in vitro dissolution tests for estimating the solubility of unknown radionuclide particles within the context of a simple model such as the class D, W, and Y formulation of ICRP 30

  11. Bioaccumulation of heavy metals: Application to the decontamination of solutions containing americium, plutonium and neptunium

    International Nuclear Information System (INIS)

    Of the heavy metal-containing wastes discharged by industry to the environment, the low activity streams produced by nuclear fuel reprocessing activities represent a significant challenge due to the low concentrations and complex chemical speciation of the contaminating transuranic elements. A possible biological treatment system for such wastes uses a Citrobacter sp. which accumulates heavy metals as metal phosphate precipitates via the activity of an atypical acid-type phosphatase. Successful and sustained accumulation of the uranyl (UO22+) ion has been reported previously. In the present work La(III) and Th(IV) were used as analogues (surrogates) of the equivalent, more radiotoxic actinide oxidation states. Enzymatically-mediated removal of both surrogates and the corresponding actinide elements was demonstrated in a model flow-through system using immobilized cells within a fixed-bed cartridge bioreactor

  12. New Synthetic Methods and Structure-Property Relationships in Neptunium, Plutonium, and Americium Borates. Final report

    International Nuclear Information System (INIS)

    The past three years of support by the Heavy Elements Chemistry Program have been highly productive in terms of advanced degrees awarded, currently supported graduate students, peer-reviewed publications, and presentations made at universities, national laboratories, and at international conferences. Ph.D. degrees were granted to Shuao Wang and Juan Diwu, who both went on to post-doctoral appointments at the Glenn T. Seaborg Center at Lawrence Berkeley National Laboratory with Jeff Long and Ken Raymond, respectively. Pius Adelani completed his Ph.D. with me and is now a post-doc with Peter C. Burns. Andrea Alsobrook finished her Ph.D. and is now a post-doc at Savannah River with Dave Hobbs. Anna Nelson completed her Ph.D. and is now a post-doc with Rod Ewing at the University of Michigan. As can be gleaned from this list, students supported by the Heavy Elements Chemistry grant have remained interested in actinide science after leaving my program. This follows in line with previous graduates in this program such as Richard E. Sykora, who did his post-doctoral work at Oak Ridge National Laboratory with R. G. Haire, and Amanda C. Bean, who is a staff scientist at Los Alamos National Laboratory, and Philip M. Almond and Thomas C. Shehee, who are both staff scientists at Savannah River National Laboratory, Gengbang Jin who is a staff scientist at Argonne National Lab, and Travis Bray who has been a post-doc at both LBNL and ANL. Clearly this program is serving as a pipe-line for students to enter into careers in the national laboratories. About half of my students depart the DOE complex for academia or industry. My undergraduate researchers also remain active in actinide chemistry after leaving my group. Dan Wells was a productive undergraduate of mine, and went on to pursue a Ph.D. on uranium and neptunium chalcogenides with Jim Ibers at Northwestern. After earning his Ph.D., he went directly into the nuclear industry

  13. Concordant plutonium-241-americium-241 dating of environmental samples: results from forest fire ash

    Energy Technology Data Exchange (ETDEWEB)

    Goldstein, Steven J [Los Alamos National Laboratory; Oldham, Warren J [Los Alamos National Laboratory; Murrell, Michael T [Los Alamos National Laboratory; Katzman, Danny [Los Alamos National Laboratory

    2010-12-07

    We have measured the Pu, {sup 237}Np, {sup 241}Am, and {sup 151}Sm isotopic systematics for a set of forest fire ash samples from various locations in the western U.S. including Montana, Wyoming, Idaho, and New Mexico. The goal of this study is to develop a concordant {sup 241}Pu (t{sub 1/2} = 14.4 y)-{sup 241}Am dating method for environmental collections. Environmental samples often contain mixtures of components including global fallout. There are a number of approaches for subtracting the global fallout component for such samples. One approach is to use {sup 242}/{sup 239}Pu as a normalizing isotope ratio in a three-isotope plot, where this ratio for the nonglobal fallout component can be estimated or assumed to be small. This study investigates a new, complementary method of normalization using the long-lived fission product, {sup 151}Sm (t{sub 1/2} = 90 y). We find that forest fire ash concentrates actinides and fission products with {approx}1E10 atoms {sup 239}Pu/g and {approx}1E8 atoms {sup 151}Sm/g, allowing us to measure these nuclides by mass spectrometric (MIC-TIMS) and radiometric (liquid scintillation counting) methods. The forest fire ash samples are characterized by a western U.S. regional isotopic signature representing varying mixtures of global fallout with a local component from atmospheric testing of nuclear weapons at the Nevada Test Site (NTS). Our results also show that {sup 151}Sm is well correlated with the Pu nuclides in the forest fire ash, suggesting that these nuclides have similar geochemical behavior in the environment. Results of this correlation indicate that the {sup 151}Sm/{sup 239}Pu atom ratio for global fallout is {approx}0.164, in agreement with an independent estimate of 0.165 based on {sup 137}Cs fission yields for atmospheric weapons tests at the NTS. {sup 241}Pu-{sup 241}Am dating of the non-global fallout component in the forest fire ash samples yield ages in the late 1950's-early 1960's, consistent with a peak in NTS weapons testing at that time. The age results for this component are in agreement using both {sup 242}Pu and {sup 151}Sm normalizations, although the errors for the {sup 151}Sm correction are currently larger due to the greater uncertainty of their measurements. Additional efforts to develop a concordant {sup 241}Pu-{sup 241}Am dating method for environmental collections are underway with emphasis on soil cores.

  14. Rapid selective separation of americium/curium from simulated nuclear forensic matrices using triazine ligands

    Energy Technology Data Exchange (ETDEWEB)

    Higginson, Matthew A.; Livens, Francis R.; Heath, Sarah L. [Manchester Univ. (United Kingdom). Centre for Radiochemistry Research; Thompson, Paul; Marsden, Olivia J. [AWE, Aldermaston, Reading (United Kingdom); Harwood, Laurence M.; Hudson, Michael J. [Reading Univ. (United Kingdom). Dept. of Chemistry; Lewis, Frank W. [Reading Univ. (United Kingdom). Dept. of Chemistry; Northumbria Univ., Newcastle upon Tyne (United Kingdom). Dept. of Chemical and Forensic Sciences

    2015-07-01

    In analysis of complex nuclear forensic samples containing lanthanides, actinides and matrix elements, rapid selective extraction of Am/Cm for quantification is challenging, in particular due the difficult separation of Am/Cm from lanthanides. Here we present a separation process for Am/Cm(III) which is achieved using a combination of AG1-X8 chromatography followed by Am/Cm extraction with a triazine ligand. The ligands tested in our process were CyMe{sub 4}-BTPhen, CyMe{sub 4}-BTBP, CA-BTP and CA-BTPhen. Our process allows for purification and quantification of Am and Cm (recoveries 80% - 100%) and other major actinides in < 2 d without the use of multiple columns or thiocyanate. The process is unaffected by high level Ca(II)/Fe(III)/Al(III) (10 mg mL{sup -1}) and thus requires little pre-treatment of samples.

  15. Affinity of finely dispersed montmorillonite colloidal particles for americium and lanthanides

    International Nuclear Information System (INIS)

    We studied (i) the affinity of the finely dispersed montmorillonite colloidal particles (3+ and lanthanide ions (Ln3+: Nd3+, Eu3+, Gd3+), and (ii) the differences between the sorption behavior of Am3+ and Ln3+ onto the colloidal particles and that onto the massive montmorillonite solids. The ion-exchange stoichiometry of sorption reaction of Am3+ and Ln3+ onto the colloidal particles was 1:3 in the low Na+ concentration region. In the high Na+ concentration region, the sorption ratio was constant, and specific for Am3+ and each Ln3+. The influence of Na+ and Ca2+ on the sorption of Ln3+ onto the finely dispersed Na- and Ca-montmorillonite colloidal particles at different NaCl and CaCl2 concentrations was examined. It was found that the coverage of the sorption sites increased with the Ln3+ concentration. The affinity for Ln3+ was discussed by selectivity and a Langmuir-type isotherm. (orig.)

  16. Combined procedure using radiochemical separation of plutonium, americium and uranium radionuclides for alpha-spectrometry

    International Nuclear Information System (INIS)

    Radiochemical separation of Pu, Am and U was tested from synthetic solutions and evaporator concentrate samples from nuclear power plants for isolation of each of them for alpha-spectrometry analysis. The separation was performed by anion-exchange chromatography, extraction chromatography, using TRU resin, and precipitation techniques. The aim of the study was to develop a sensitive analytical procedure for the sequential determination of 242Pu, 238Pu, 239+240Pu, 241Am and 235,238U in radioactive wastes. 238Pu, 242Pu, 243Am and 232U were used as tracers. The measurements of α emitting radionuclides were performed by semiconductor detector that is used especially when spectrometric information is needed. For synthetic solutions the chemical recovery was based on associated iron concentration and was about 93%. (author)

  17. Supercritical fluid extraction of plutonium and americium from soil using thenoyltrifluoroacetone and tributylphosphate complexation

    International Nuclear Information System (INIS)

    Samples of clean soil from the source used to backfill pits at the Idaho National Engineering and Environmental Laboratory's Radioactive Waste Management Complex were spiked with 239Pu and 241Am to evaluate ligand-assisted supercritical fluid extraction as a decontamination method. The actual soil in the pits has been subject to approximately three decades of weathering since it was originally contaminated. No surrogate soil can perfectly simulate the real event, but actual contaminated soil was not available for research purposes. However, fractionation of Am and Pu in the surrogate soil was found to be similar to that previously measured in the real soil using a sequential aqueous extraction procedure. This suggests that Pu and Am behavior are similar in the two soils. The surrogate was subjected to supercritical carbon dioxide extraction, in the presence of the fluorinated beta diketone thenoyltrifluoroacetone (TTA), and tributylphosphate (TBP). As much as 69% of the Pu and 88% of the Am were removed from the soil using 3.2 mol % TTA and 2.7 mol % TBP, in a single 45 minute extraction. Extraction conditions employing a 5 mol % ethanol modifier with 0.33 mol % TTA and 0.27 mol % TBP resulted in 66% Pu and 68% Am extracted. To our knowledge, this is the first report of the use of supercritical fluid extraction (SFE) for the removal of actinides from soil. (orig.)

  18. Heat capacity, thermal conductivity and thermal diffusivity of uranium–americium mixed oxides

    International Nuclear Information System (INIS)

    Highlights: • The (U1-y,Amy)O2-x mixed oxides with y = 0.0877 and 0.1895 and x = 0.01–0.03 was studied. • Enthalpy increments measured from 425 K up to 1790 K by drop calorimetry. • Thermal diffusivity was measured from 500 to 1550 K. • Heat capacity of the (U, Am)O2-x solid solution was thus obtained for the first time. • For thermal conductivity a correlation using a classical phonon transport model is proposed. - Abstract: The enthalpy increments of (U1-y,Amy)O2-x mixed oxides with y = 0.0877 and 0.1895 and x = 0.01–0.03 were measured using drop calorimetry in the temperature range 425–1790 K and the heat capacity was obtained as differential of the obtained enthalpy increments with respect to temperature. The thermal diffusivity was measured using the laser flash technique from 500 to 1550 K. The thermal conductivity was calculated from the measured thermal diffusivity, density and heat capacity. Measured enthalpy increments of the (U1-y,Amy)O2-x solid solutions are very close to the end members, indicating no excess contribution. The derived heat capacities for the two intermediate compositions are slightly higher than that of UO2 and in a good agreement with literature data of AmO2 up to 1100 K. For the thermal conductivity of (U, Am)O2−x mixed oxides a correlation using the classical phonon transport model in crystal structures is proposed

  19. Mean squared slowing-down distance and age of americium-beryllium neutrons in perspex

    International Nuclear Information System (INIS)

    THe mean squared slowing-down distance 2>, and the age to thermal capture (Migration Area), M2, are direct measures of the slowing.down, and the spreading out, processes of neutrons in a medium. They also enter directly into reactor calculations. These parameters have been determined experimentally for Am-Be neutrons (mean energy 4.46 MeV), in a block of perspex, using the activities induced in thin indium foils from the 115In(n,γ)116In reactions. (author) 13 refs.; 5 figs.; 2 tabs

  20. A method for the in vivo measurement of americium-241 at long times post-exposure

    International Nuclear Information System (INIS)

    This study investigated an improved method for the quantitative measurement, calibration and calculation of 241Am organ burdens in humans. The techniques developed correct for cross-talk or count-rate contributions from surrounding and adjacent organ burdens and assures for the proper assignment of activity to the lungs, liver and skeleton. In order to predict the net count-rates for the measurement geometries of the skull, liver and lung, a background prediction method was developed. This method utilizes data obtained from the measurement of a group of control subjects. Based on this data, a linear prediction equation was developed for each measurement geometry. In order to correct for the cross-contributions among the various deposition loci, a series of surrogate human phantom structures were measured. The results of measurements of 241Am depositions in six exposure cases have been evaluated using these new techniques and have indicated that lung burden estimates could be in error by as much as 100 percent when corrections are not made for contributions to the count-rate from other organs

  1. Distribution of plutonium and americium in human and animal tissues after chronic exposures

    International Nuclear Information System (INIS)

    The distribution of plutonium in the tissues of a group of southern Finns was determined. Their Pu intake had been solely from fallout via inhalation. A group of northern Finns was also studied. They obtain most of the Pu from inhalation, but also some from their diet which is rich in reindeer liver. Reindeer obtain large amounts of transuranium elements in their natural winter diet, which mainly consists of lichen. Pu-239, 240 and Am-241 were also analyzed in elk because it is closely related to reindeer but does not feed on lichen. It was found that much of the Am-241 in reindeer tissues is due to ingrowth from Pu-241 in the animal. The aim of this study to establish whether this situation is also true for the human bone. (H.K.)

  2. Optimization conditions for the separation of rare earth elements, americium, curium and cesium with HPLC technique

    International Nuclear Information System (INIS)

    In order to validate the neutronic code calculations used in the nuclear field, it is necessary to quantify the isotopic composition of the nuclear irradiated fuels with high precision and accuracy. A separation step whose objective is to isolate the elements of interest in a fraction as pure as possible, is performed before mass spectrometry detection (MC-ICP-MS, TIMS), in order to eliminate isobaric interferences. In a first step, uranium and plutonium are separated from the fission products by ion exchange chromatography. Then, fission products are separated by high performance liquid chromatography (HPLC). A gradient separation with a silica sulphonated support as stationary phase and hydroxy-methyl butyric acid (HMB) as eluent solution provides a good degree of separation of the rare earth elements, Am, Cm and Cs. But, for a same manufacturer, the rate of sulphonated groups is variable from one column to another for a given production batch. For every replacement of column, it is necessary to adjust the separation conditions. Furthermore, the high radioactivity of the samples injected damages the stationary phase, dragging a regular renewal of the columns. The goal of this study is to determine the optimal separation conditions with a minimum of tests in order to limit the time assigned to this operation. A first Doehlert experimental design with pH and HMB concentration as variables has been implemented to optimize Gd, Eu separation, in isocratic initial conditions. A second one has been tested in order to separate the higher lanthanides and to fix the final conditions of the gradient separation. A last set of tests has been performed to characterize the cesium behaviour. Finally, the gradient conditions have been adjusted in order to perform the full separation of lanthanides, Cs, Am and Cm with nuclear facilities. (author)

  3. Separation of americium(III) from lanthanides(III) by nanofiltration-complexation in aqueous medium

    International Nuclear Information System (INIS)

    The separation of Am(III) from a mixture of lanthanides(III) was performed in aqueous medium by nanofiltration combined with a complexation step using a DTPA derivative as selective complexing agent. (author)

  4. Subsurface Behavior of Plutonium and Americium at Non-Hanford Sites and Relevance to Hanford

    Energy Technology Data Exchange (ETDEWEB)

    Cantrell, Kirk J.; Riley, Robert G.

    2008-02-01

    Seven sites where Pu release to the environment has raised significant environmental concerns have been reviewed. A summary of the most significant hydrologic and geochemical features, contaminant release events and transport processes relevant to Pu migration at the seven sites is presented.

  5. Extraction of europium and americium by a mixture of CMPO and dicarbollide

    International Nuclear Information System (INIS)

    The extraction of Eu3+ and Am3+ by a mixture of CMPO and dicarbollide in nitrobenzene has been studied. The synergetic effect of dicarbollide is pronounced at low acidities but still lower than for previously studied DBDECMP. Separation properties towards Am/Eu pair are small. (author) 6 refs.; 2 figs

  6. Separation of Americium from Fission Product Lanthanides Using Cyanex 301 Extraction

    Institute of Scientific and Technical Information of China (English)

    ZHU Yongjun; CHEN Jing

    2001-01-01

    The extraction behavior of bis (2,4,4-trimethylpentyl)dithiophosphinic acid (HBTMPDTP),purified from Cyanex 301,was studied for extracting Am3+ and trivalent lanthanides (Lns).HBTMPDTP shows very high selectivity for Am.Separation factor(SF)of Am and Eu,SF Am/Eu,(trace amount)reaches a high value of 5.9×103 and SF Am/(Pr+Nd) (macro amount)is about 2×103.The mathematical model for the distribution ratios and process parameters calculated for HBTMPDTP extraction was established and the calculated results were verified experimentally.In a five-stage countercurrent process,the extraction rates of Am and Lns were >99.999% and 0.14%,respectively,to fulfill the separation requirements.The efficiency of this process was also verified in a cross-flow extraction experiment using a genuine Am-FPLns fraction.In the presence of TBP,the extraction of Am and Eu is enhanced,but their separation is reduced to some extent.A fairly good separation was achieved in a fractional extraction process using a mixture of HBTMPDTP and TBP in kerosene at low pH.

  7. New Synthetic Methods and Structure-Property Relationships in Neptunium, Plutonium, and Americium Borates. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Albrecht-Schmitt, Thomas Edward

    2013-09-14

    The past three years of support by the Heavy Elements Chemistry Program have been highly productive in terms of advanced degrees awarded, currently supported graduate students, peer-reviewed publications, and presentations made at universities, national laboratories, and at international conferences. Ph.D. degrees were granted to Shuao Wang and Juan Diwu, who both went on to post-doctoral appointments at the Glenn T. Seaborg Center at Lawrence Berkeley National Laboratory with Jeff Long and Ken Raymond, respectively. Pius Adelani completed his Ph.D. with me and is now a post-doc with Peter C. Burns. Andrea Alsobrook finished her Ph.D. and is now a post-doc at Savannah River with Dave Hobbs. Anna Nelson completed her Ph.D. and is now a post-doc with Rod Ewing at the University of Michigan. As can be gleaned from this list, students supported by the Heavy Elements Chemistry grant have remained interested in actinide science after leaving my program. This follows in line with previous graduates in this program such as Richard E. Sykora, who did his post-doctoral work at Oak Ridge National Laboratory with R. G. Haire, and Amanda C. Bean, who is a staff scientist at Los Alamos National Laboratory, and Philip M. Almond and Thomas C. Shehee, who are both staff scientists at Savannah River National Laboratory, Gengbang Jin who is a staff scientist at Argonne National Lab, and Travis Bray who has been a post-doc at both LBNL and ANL. Clearly this program is serving as a pipe-line for students to enter into careers in the national laboratories. About half of my students depart the DOE complex for academia or industry. My undergraduate researchers also remain active in actinide chemistry after leaving my group. Dan Wells was a productive undergraduate of mine, and went on to pursue a Ph.D. on uranium and neptunium chalcogenides with Jim Ibers at Northwestern. After earning his Ph.D., he went directly into the nuclear industry.

  8. Distribution of plutonium and americium beneath a 33-year-old liquid waste disposal site

    International Nuclear Information System (INIS)

    The distribution of Pu, 241Am, and water in Bandelier Tuff beneath a former liquid waste disposal site at Los Alamos was investigated. The waste use history of the site was described, as well as the previous field and laboratory studies of radionuclide migration performed at this site. One of the absorption beds studied had 20.5 m of water added to it in 1961 in an aggressive attempt to change the distribution of radionuclides in the tuff beneath the bed. Plutonium and 241Am were detected to sampling depths of 30 m in this bed, but only found to depths of 6.5 to 13.41 m in an adjacent absorption bed (bed 2) not receiving additional water in 1961. After 17 yr of migration of the slug water added to bed 1, 0.3 to 5.1% of the Pu inventory and 3.0 to 49.6% of the 241Am inventory was mobilized within the 30-m sampling depth, as less than one column volume of water moved through the tuff profile under the bed. The results of similar lab and field studies performed since 1953 were compared with our 1978 data and site hydrologic data was used as a time marker to estimate how fast radionuclide migration occurred in the tuff beneath absorption bed 1. Most of the radionuclide migration appeared to have occurred within 1 yr of the 20.5-m water leaching in 1961. 16 references, 2 figures, 4 tables

  9. Coulometric Titration of Microgram Amounts of Americium at the Conducting Glass Electrode

    International Nuclear Information System (INIS)

    Coulograms of Am(III) in carbonate electrolyte exhibit a well-defined wave for the Am(III)-Am(V) oxidation step at the conduction glass electrode. This wave provides the basis of a method for the quantitative titration of this element at the 30-microgram level with a precision of 1.5 percent. The method is restricted to pure solutions; corrections are required for the partial oxidation of Am(V) to Am(VI) and the reduction of Am(VI) by water

  10. Americium and plutonium separation by extraction chromatography for determination by accelerator mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Kazi, Zakir H. [Department of Earth Science, University of Ottawa, 140 Louis Pasteur Avenue, Ottawa K1N 6N5 (Canada); Cornett, Jack R., E-mail: jack.cornett@uottawa.ca [Department of Earth Science, University of Ottawa, 140 Louis Pasteur Avenue, Ottawa K1N 6N5 (Canada); Zhao, Xaiolei; Kieser, Liam [Department of Physics, University of Ottawa, 140 Louis Pasteur Avenue, Ottawa K1N 6N5 (Canada)

    2014-06-01

    Highlights: • Am and Pu were adsorbed and separated using a single extraction chromatography DGA column. • Pu was eluted from the column completely using on-column reduction of Pu(IV) to Pu(III). • ²⁴¹Am and 239,240Pu measurements by accelerator mass spectrometry (AMS) agree with the certified values in two SRMs. Abstract: A simple method was developed to separate Pu and Am using single column extraction chromatography employing N,N,N',N'-tetra-n-octyldiglycolamide (DGA) resin. Isotope dilution measurements of Am and Pu were performed using accelerator mass spectrometry (AMS) and alpha spectrometry. For maximum adsorption Pu was stabilized in the tetra valent oxidation state in 8 M HNO₃ with 0.05 M NaNO₂ before loading the sample onto the resin. Am(III) was adsorbed also onto the resin from concentrated HNO₃, and desorbed with 0.1 M HCl while keeping the Pu adsorbed. The on-column reduction of Pu(IV) to Pu(III) with 0.02 M TiCl₃ facilitated the complete desorption of Pu. Interferences (e.g. Ca²⁺, Fe³⁺) were washed off from the resin bed with excess HNO₃. Using NdF₃, micro-precipitates of the separated isotopes were prepared for analysis by both AMS and alpha spectrometry. The recovery was 97.7 ± 5.3% and 95.5 ± 4.6% for ²⁴¹Am and ²⁴²Pu respectively in reagents without a matrix. The recoveries of the same isotopes were 99.1 ± 6.0 and 96.8 ± 5.3% respectively in garden soil. The robustness of the method was validated using certified reference materials (IAEA 384 and IAEA 385). The measurements agree with the certified values over a range of about 1–100 Bq kg⁻¹. The single column separation of Pu and Am saves reagents, separation time, and cost.

  11. Plutonium and americium in air on the coasts of the Irish Sea

    International Nuclear Information System (INIS)

    Measurements of artificial radionuclides in air, deposition and seawater were carried out at coastal and inland locations in Cumbria, south-west Scotland, Northern Ireland and North Wales. The measurements were undertaken to determine the distribution of artificial radionuclides in the coastal environment attributable to discharges from Sellafield and to investigate the mechanisms responsible for the increased radionuclide concentration in the marine aerosol and their subsequent transfer to land. A number of different sampling methods were used and the contribution each method could make to the understanding of the marine aerosol was assessed. Measurements of the size distribution of the marine aerosol was also undertaken. The measurements demonstrated that the actinide concentrations measured in the air and deposition at coastal locations could be related to near shore sea water concentrations, but that no direct proportionality existed. It was also determined that a significant proportion of the material transferred from sea to land was associated with larger particulate present in the marine aerosol during conditions of above average onshore winds. (author)

  12. Americium and plutonium association with magnesium hydroxide colloids in alkaline nuclear industry process environments

    Science.gov (United States)

    Maher, Zoe; Ivanov, Peter; O'Brien, Luke; Sims, Howard; Taylor, Robin J.; Heath, Sarah L.; Livens, Francis R.; Goddard, David; Kellet, Simon; Rand, Peter; Bryan, Nick D.

    2016-01-01

    The behaviours of Pu, Am and colloids in feed solutions to the Site Ion-exchange Effluent Plant (SIXEP) at the Sellafield nuclear reprocessing site in the U.K. have been studied. For both Pu and Am, fractions were found to be associated with material in the colloidal size range, with ˜50% of the Pu in the range 1-200 nm. The concentration of soluble Pu (brucite (magnesium hydroxide) colloids of different sizes was studied under alkaline conditions representative of nuclear fuel storage pond and effluent feed solution conditions. The morphology of the brucite particles in the bulk material observed by ESEM was predominantly hexagonal, while that of the carbonated brucite consisted of hexagonal species mixed with platelets. The association of 241Am(III) with the brucite colloids was studied by ultrafiltration coupled with gamma ray-spectrometry. For carbonate concentrations up to 10-3 M, the 241Am(III) was mainly associated with larger colloids (>300 kDa), and there was a shift from the smaller size fractions to the larger over a period of 6 months. At higher carbonate concentrations (10-2 M), the Am was predominantly detected in the true solution fraction (<3 kDa) and in smaller size colloidal fractions, in the range 3-100 kDa.

  13. Estimation of americium in cemented waste block using gamma ray spectrometry

    International Nuclear Information System (INIS)

    A method was developed for the estimation of 241Am present in the cemented waste block which was cylindrical in shape. In such large sample, the attenuation of gamma rays increases with size of the sample and density of the material present. Attenuation correction was incorporated using linear attenuation coefficients of 59.54 keV gamma ray of 241Am. Also in such large samples, error due to the distribution of activity is more. Estimation of 241Am in the cemented sample was carried out by applying corrections for attenuation and for the sample geometry. (author)

  14. Sorption of americium in tuff and pure minerals using synthetic and natural groundwaters

    International Nuclear Information System (INIS)

    The distribution of Am between selected solid and liquid phases has been studied using initial 241Am solutions with a molarity smaller than 1 x 10-11. The synthetic and natural groundwaters used have pH values in the 7--8 range and a total alkalinity of approximately 1 mN which is mainly due to bicarbonate. Mass spectrometric isotope dilution was utilized to determine the amount of Am in the solution phase initially and after equilibrium was attained. Using this sensitive technique, 7 x 108 atoms of 241Am were accurately measured. Our results indicate that the percent of Am lost to the walls of the container in the absence of geologic material varies from 35 to 84. The Am sorption coefficient determined is on the order of 103 ml/g for clinoptilolite, 104 ml/g for tuff consisting mainly of alkali feldspar and cristobalite, and 105 ml/g for romanechite. 12 refs

  15. Post irradiation examination of irradiated americium oxide and uranium dioxide in magnesium aluminate spinel

    International Nuclear Information System (INIS)

    To study MgAl2O4 spinel as inert matrix material for the transmutation of minor actinides, two capsules were irradiated at the high flux reactor in Petten, containing 12.5 wt% micro-dispersed 241AmOx in spinel and 25 wt% micro-dispersed enriched UO2 in spinel. During irradiation, the initially present 241Am was converted for 99.8% to fission products (50%), plutonium (30%), curium (16%) and 243Am (4%). The UO2 spinel target experienced a burn-up of 32% fission per initial metal atom. The post irradiation examination of the AmOx inert matrix target showed swelling of 27 vol.%, and a gas release of 48% for He and 16% for Xe and Kr. The UO2 inert matrix target also showed a large volumetric swelling of 11%, directed mainly radially. Ceramography on the UO2 inert matrix target revealed a complete restructuring of the spinel grains upon irradiation and the absence of porosity, suggesting that amorphisation is the main cause of the swelling

  16. Post irradiation examination of irradiated americium oxide and uranium dioxide in magnesium aluminate spinel

    Science.gov (United States)

    Klaassen, F. C.; Bakker, K.; Schram, R. P. C.; Klein Meulekamp, R.; Conrad, R.; Somers, J.; Konings, R. J. M.

    2003-06-01

    To study MgAl 2O 4 spinel as inert matrix material for the transmutation of minor actinides, two capsules were irradiated at the high flux reactor in Petten, containing 12.5 wt% micro-dispersed 241AmO x in spinel and 25 wt% micro-dispersed enriched UO 2 in spinel. During irradiation, the initially present 241Am was converted for 99.8% to fission products (50%), plutonium (30%), curium (16%) and 243Am (4%). The UO 2 spinel target experienced a burn-up of 32% fission per initial metal atom. The post irradiation examination of the AmO x inert matrix target showed swelling of 27 vol.%, and a gas release of 48% for He and 16% for Xe and Kr. The UO 2 inert matrix target also showed a large volumetric swelling of 11%, directed mainly radially. Ceramography on the UO 2 inert matrix target revealed a complete restructuring of the spinel grains upon irradiation and the absence of porosity, suggesting that amorphisation is the main cause of the swelling.

  17. Post irradiation examination of irradiated americium oxide and uranium dioxide in magnesium aluminate spinel

    Energy Technology Data Exchange (ETDEWEB)

    Klaassen, F.C. E-mail: klaassen@nrg-nl.com; Bakker, K.; Schram, R.P.C.; Klein Meulekamp, R.; Conrad, R.; Somers, J.; Konings, R.J.M

    2003-06-01

    To study MgAl{sub 2}O{sub 4} spinel as inert matrix material for the transmutation of minor actinides, two capsules were irradiated at the high flux reactor in Petten, containing 12.5 wt% micro-dispersed {sup 241}AmO{sub x} in spinel and 25 wt% micro-dispersed enriched UO{sub 2} in spinel. During irradiation, the initially present {sup 241}Am was converted for 99.8% to fission products (50%), plutonium (30%), curium (16%) and {sup 243}Am (4%). The UO{sub 2} spinel target experienced a burn-up of 32% fission per initial metal atom. The post irradiation examination of the AmO{sub x} inert matrix target showed swelling of 27 vol.%, and a gas release of 48% for He and 16% for Xe and Kr. The UO{sub 2} inert matrix target also showed a large volumetric swelling of 11%, directed mainly radially. Ceramography on the UO{sub 2} inert matrix target revealed a complete restructuring of the spinel grains upon irradiation and the absence of porosity, suggesting that amorphisation is the main cause of the swelling.

  18. A consistent set of thermodynamic constants for americium (III) species with hydroxyl and carbonate

    International Nuclear Information System (INIS)

    A consistent set of thermodynamic constants for aqueous species, and compounds of Am(III) with hydroxyl and carbonate ligands has been developed. The procedure used to develop these constants involved establishing a value for one formation constant at a time in a sequential order, starting with the hydrolysis products and hydroxide solids, and then proceeding to carbonate species. The EQ3NR chemical-equilibrium model was used to test the constants developed. These constants are consistent with most of the experimental data that form their basis; however, considerable uncertainty still exists in some aspects of the Am(III) data

  19. Americium-Curium Stabilization - 5'' Cylindrical Induction Melter System Design Basis

    International Nuclear Information System (INIS)

    Approximately 11,000 liters (3,600) gallons of solution containing isotopes of Am and Cm are currently stored in F-Canyon Tank 17.1. These isotopes were recovered during plutonium-242 production campaigns in the mid- and late-1970s. Experimental work for the project began in 1995 by the Savannah River Technology Center (SRTC). Details of the process are given in the various sections of this document

  20. Rapid selective separation of americium/curium from simulated nuclear forensic matrices using triazine ligands

    International Nuclear Information System (INIS)

    In analysis of complex nuclear forensic samples containing lanthanides, actinides and matrix elements, rapid selective extraction of Am/Cm for quantification is challenging, in particular due the difficult separation of Am/Cm from lanthanides. Here we present a separation process for Am/Cm(III) which is achieved using a combination of AG1-X8 chromatography followed by Am/Cm extraction with a triazine ligand. The ligands tested in our process were CyMe4-BTPhen, CyMe4-BTBP, CA-BTP and CA-BTPhen. Our process allows for purification and quantification of Am and Cm (recoveries 80% - 100%) and other major actinides in < 2 d without the use of multiple columns or thiocyanate. The process is unaffected by high level Ca(II)/Fe(III)/Al(III) (10 mg mL-1) and thus requires little pre-treatment of samples.

  1. Plutonium, americium and other actinides on Belarus territory: source, levels, risks

    International Nuclear Information System (INIS)

    For Belarus it was showed that in result of falling during nuclear trials happened contamination of upper soil layer by transuranium elements with medium level of contamination for 239,240Pu 53±17 Bq/m2. After Chernobyl accident this characteristic equal 1.1· Bq/m2 on the south of Belarus. In result accident it was revealed 17 actinides. For Chernobyl falling was determined big contents of 241Pu that will lead to maximum value of 241Am in 2059, which will be more in 2,5 times than 239,240Pu

  2. Effect of solvent on in vitro dissolution: Summary of results for uranium, americium, and cobalt aerosols

    Energy Technology Data Exchange (ETDEWEB)

    Guilmette, R.A.; Hoover, M.D.

    1995-12-01

    The revised 10 CFR Part 20 has adopted the ICRP Publication 30 method for calculating the committed effective dose equivalent from intakes of radionuclides. This dosimetry scheme requires knowledge or assumptions about the chemical form of the radionuclide, its particle size, and its known or assumed solubility. The solubility is classified as being either D (relatively soluble), W, or Y (relatively insoluble), depending on whether the material dissolves over periods of days, weeks, or years. Although Nuclear Regulatory Commission licensees may wish to take advantage of material-specific knowledge in order to adjust annual limits on intake and derived air concentrations, relatively few radioactive materials to which workers and the general population may be exposed have been adequately characterized either in terms of physicochemical form or solubility. Experimental measurement of solubility using some type of in vitro dissolution measurement system is therefore needed. However, there is currently no clear consensus regarding the appropriate design of in vitro dissolution systems, particularly when considering the range of different radionuclides to be studied, and the complexity of the biological mechanisms involved in the retention and clearance of inhaled deposited radioactive particles. The purpose of this study was to evaluate the effect of the several solvents on the dissolution of four test aerosols ({sup 57}Co{sub 3}O{sub 4}, {sup 241}AmO{sub 2}, ammonium diuranate [ADU], and U{sub 3}O{sub 8}) selected to encompass a variety of chemical and biochemical properties in vivo. The results of this study provide some guidance on the usefulness of in vitro dissolution tests for estimating the solubility of unknown radionuclide particles within the context of a simple model such as the class D, W, and Y formulation of ICRP 30.

  3. Photooxidation of americium(III) by water in bicarbonate-carbonate solutions

    International Nuclear Information System (INIS)

    The effects of ultraviolet (UV) and visible light on aqueous Am(III) solutions (1.1 x 10-4 mol/l) containing KHCO3 or K2CO3 or K2CO3 + KHCO3 were studied by spectrophotometry. It was found that Am(IV) was gradually formed upon irradiation with UV light. Its concentration settled at a value of approximately 60% of the initial Am(III) concentration within 6 h. Specially prepared Am (IV) was partially reduced to Am(III) concentration, pH, and total concentration of HCO3- and CO32-. The presence of oxygen had no effect on the rate of the process. Laser radiation of a wavelength of 510.6 nm produced no oxidation of Am(III). It was suggested that the excited complex ion of Am(III) forms an excimer with the unexcited ion Am(III); H2 elimnation from this excimer yields Am(IV)

  4. Influence of humic-acid complexing on the mobility of Americium in the soil aquatic environment

    International Nuclear Information System (INIS)

    Diffusion data indicate the Am, Cm and Np migrate 1.2, 0.8, and 26 centimeters, respectively, in a thousand years. Thus, excluding mass transport by moving water or wind, actinide elements, such as Cm, Am, and Np that find their way to the soil-aquatic environment are relatively immobile. Measured diffusion coefficients, corrected for distribution between the aqueous and soil phases, tortuosity, negative absorption, and relative fluidity are in reasonable agreement with aqueous diffusion coefficients. However, agreement depends strongly on measurement method used to determine distribution ratios. Two sets of experiments with 241Am and 152Eu tracers have been done to measure distribution ratios as a function of the aqueous humic acid concentration. In the first experiments the solid phase was kaolinite and in the second series of distribution ratios were measured with Burbank sandy loam. Both of these experiments indicated that Am(III) and Eu(III) form very strong humic acid complexes with formation constants of approximately 105. Additional experiments are being done to establish the average number of Am(III)s or Eu(III)s bound to the humic acid polymer

  5. Optimization of TRPO Process Parameters for Americium Extraction from High Level Waste

    Institute of Scientific and Technical Information of China (English)

    CHEN Jing; WANG Jianchen; SONG Chongli

    2001-01-01

    The numerical calculations for Am multistage fractional extraction by trialkyl phosphine oxide (TRPO) were verified by a hot test.1750 L/t-U high level waste (HLW) was used as the feed to the TRPO process.The analysis used the simple objective function to minimize the total waste content in the TRPO process streams.Some process parameters were optimized after other parameters were selected.The optimal process parameters for Am extraction by TRPO are:10 stages for extraction and 2 stages for scrubbing;a flow rate ratio of 0.931 for extraction and 4.42 for scrubbing;nitric acid concentration of 1.35 mol/L for the feed and 0.5 mol/L for the scrubbing solution.Finally,the nitric acid and Am concentration profiles in the optimal TRPO extraction process are given.

  6. Neutron capture and neutron-induced fission experiments on americium isotopes with DANCE

    International Nuclear Information System (INIS)

    Neutron capture cross section data on Am isotopes were measured using the Detector for Advanced Neutron Capture Experiments (DANCE) at Los Alamos National Laboratory. The neutron capture cross section was determined for 241Am for neutron energies between thermal and 320 keV. Preliminary results were also obtained for 243Am for neutron energies between 35 eV and 200 keV. The results on concurrent neutron-induced fission and neutron-capture measurements on 242mAm will be presented, where the fission events were actively triggered during the experiments. In these experiments, the Parallel-Plate Avalanche Counter (PPAC) detector that surrounds the target located in the center of the DANCE array was used as a fission-tagging detector to separate (n,γ) from (n,f) events. The first evidence of neutron capture on 242mAm in the resonance region in between 2 and 9 eV of the neutron energy was obtained.

  7. Role of natural dissolved organic compounds in determining the concentrations of americium in natural waters

    International Nuclear Information System (INIS)

    Concentrations of 241Am, both in solution and bound to suspended particulate matter, have been measured in several North American lakes. Dissolved concentrations vary from 0.4 μBq/L to 85 μBq/L. The 241Am in these lakes originated solely from global fallout and hence entered all lakes in the same physiocochemical form. The observed differences in solubility behavior must, therefore, be attributable to chemical and/or hydrological differences among the lakes. Concentrations of dissolved 241Am are highly correlated with the corresponding concentrations of /sup 239, 240/Pu(III,IV), suggesting that a common factor is responsible for maintaining both in solution. The K/sub D/ values for 241Am and /sup 239, 240/Pu(III,IV) are highly correlated with the concentrations of dissolved organic carbon (DOC) in the waters, suggesting that the common factor is the formation of soluble complexes with natural DOC for both elements. This hypothesis was tested in a series of laboratory experiments in which the DOC from several of the lakes was isolated by ultrafiltration. Plots of K/sub D/, as a function of DOC concentration, show K/sub D/ to be very high (approx.106) at low DOC concentrations. Above critical concentrations (a few mg/L DOC) the K/sub D/ values begin a progressive decrease with increasing DOC. We conclude that in most surface waters, the dissolved 241Am concentration is regulated by an adsorption/desorption equilibrium with the sediments (and suspended solids) and the value of K/sub D/ that characterizes this equilibrium is largely determined by the concentration of natural DOC in the water. 11 refs., 3 figs., 2 tabs

  8. Americium, curium and rare earths radionuclides in forest litter samples from Poland

    International Nuclear Information System (INIS)

    Twenty seven samples of forest litter or humus layers (A0 or A1) collected in 1991 in selected regions of Poland were analysed for the presence of 241Am, Cm isotopes and rare-earths alpha-emitters. Samples were originating from a large research project and were previously analysed for gamma-emitters and plutonium. The measurements were done using alpha spectrometry preceded by a radiochemical separation procedure. Additional low-level gamma spectrometric measurements were performed for the rare-earths fractions of samples with the aim to search for europium gamma-emitters. The applied radiochemical procedure, based on the IAEA recommendations, is described. The maximum observed specific activity of 241Am was found to be equal to (5.00 ± 0.19) Bq/kg, for 243+244Cm it was (0.25 ± 0.02) Bq/kg and for 147Sm it was (0.124 ± 0.009) Bq/kg. The possible origin of each isotope is discussed. The obtained results confirmed the presence of the non-volatile isotopes of the Chernobyl fallout in north-eastern Poland. (author)

  9. Transmutation of neptunium, americium, technetium, and iodine in fast spectrum cores driven by accelerated protons

    International Nuclear Information System (INIS)

    A neutronic analysis is presented of three incinerator subcritical lattices, driven by accelerated protons and designed to transmute the minor actinides, the 99Tc and the 129I, of light water reactor (LWR) waste. A calculational methodology must first be established to enable a neutronic burnup analysis of fission cores driven by high-energy protons. The methodology is based on the following codes: HERMES, the Forschungszentrum Juelich adaptation of HETC, for high-energy interactions; MCNP3, for neutron interactions below 20 MeV of neutron energy; and KORIGEN, the Forschungszentrum Karlsruhe adaptation of ORIGEN, for burnup analysis. A result of applying the methodology is that the minor actinides, the 99Tc, and the 129I, of LWR waste may be transmuted in subcritical cores, driven by the spallation neutrons emanating from the bombardment of the cores with 1600-MeV protons. Three cores types are required. Core type 1 is fueled by the minor actinides and is a modification of the Brookhaven National Laboratory PHOENIX. With a proton current of 20 mA, the core incinerates the minor actinide waste of 14 LWRs. Core type 2 contains the 99Tc, 129I, and plutonium waste of 19 LWRs. With a proton beam of 130 mA, the core incinerates the technetium and 60% of the iodine. With a faction of the plutonium coming out of this core, the remaining 40% of 129I is incinerated in core type 3. All three cores run to 100,000 MWd/tonne or slightly higher; on the average, no core is a net consumer of grid electricity; all are cooled by sodium but remain subcritical with the loss of coolant

  10. Efficient Separation of Europium Over Americium Using Cucurbit-[5]-uril Supramolecule: A Relativistic DFT Based Investigation.

    Science.gov (United States)

    Sadhu, Biswajit; Sundararajan, Mahesh; Bandyopadhyay, Tusar

    2016-01-19

    Achieving an efficient separation of chemically similar Am(3+)/Eu(3+) pair in high level liquid waste treatment is crucial for managing the long-term nuclear waste disposal issues. The use of sophisticated supramolecules in a rigid framework could be the next step toward solving the long-standing problem. Here, we have investigated the possibility of separating Am(3+)/Eu(3+) pair with cucurbit-[5]-uril (CB[5]), a macrocycle from the cucurbit-[n]-uril family, using relativistic density functional theory (DFT) based calculations. We have explored the structures, binding, and energetics of metal-CB[5] complexation processes with and without the presence of counterions. Our study reveals an excellent selectivity of Eu(3+) over Am(3+) with CB[5] (ion exchange free energy, ΔΔGAm/Eu > 10 kcal mol(-1)). Both metals bind with the carbonyl portals via μ(5) coordination arrangement with the further involvement of three external water molecules. The presence of counterions, particularly nitrate, inside the hydrophobic cavity of CB[5], induces a cooperative cation-anion binding, resulting in enhancement of metal binding at the host. The overall binding process is found to be entropy driven resembling the recent experimental observations (Rawat et al. Dalton Trans. 2015, 44, 4246-4258). The optimized structural parameters for Eu(3+)-CB[5] complexes are found to be in excellent agreement with the available experimental information. To rationalize the computed selectivity trend, electronic structures are further scrutinized using energy decomposition analysis (EDA), quantum theory of atom in molecules (QTAIM), Mülliken population analysis (MPA), Nalewajski-Mrojek (NM) bond order, and molecular orbital analyses. Strong electrostatic ion-dipole interaction along with efficient charge transfer between CB[5] and Eu(3+) outweighs the better degree of covalency between CB[5] and Am(3+) leading to superior selectivity of Eu(3+) over Am(3+). PMID:26741954

  11. Anomalous extraction behavior of Americium (III) in some diglycolamide isomers present in ionic liquid medium

    International Nuclear Information System (INIS)

    The alkyl derivatives of diglycolamide (DGA) such as N,N,N',N'-tetraoctyldiglycolamide (TODGA), N,N,N',N'-tetraethylhexyldiglycolamide (TEHDGA) and N,N-diethylhexyl- N',N'-dioctyldiglycolamide (DEHDODGA) are chain isomers differing only in the arrangement of carbon chain of the alkyl group. The extraction behavior of Am(III) in the solution of these diglycolamides in ionic liquid medium was studied as a function of concentration of nitric acid and diglycolamide. The results were compared with those obtained in a molecular diluent, n-dodecane. The extraction of Am(III) in ionic liquid medium increased in the order TEHDGA < TODGA < DEHDODGA, which was different from the customary trend of TEHDGA < DEHDODGA < TODGA obtained in n-DD. The anomaly observed in ionic liquid medium was probed by IR spectroscopy and measurement of stoichiometry. The stoichiometry of Am:DGA in each case was different and that exhibited a strong influence on the observed extraction trend. The unprotonated fraction of DGA, assessed from FTIR measurements, increased in the order TEHDGA < TODGA < DEHDODGA, which seems to be responsible for the observed anomalous extraction trend in DEHDODGA in ionic liquid medium. (author)

  12. Measurement of penetration depths of plutonium and americium in sediment from the ocean floor

    International Nuclear Information System (INIS)

    The clay-like sediment covering the ocean floor constitutes the last barrier that shields the biosphere from contamination by radionuclides stemming from the nuclear wastes of a subsea repository. In the event of a failure of the engineered barriers, the mobility of the released radionuclides in the sediment determines the rate and extent of entry into the water of the ocean. In this article, the initial results of measurements designed to determine the mobility of transuranium elements in sediment from the ocean floor are presented. Data indicate very low migration rates and imply strong chemisorptive interaction with the sediment

  13. Study on the uptake of Americium using PC88A - impregnated macroporous polymeric beads

    International Nuclear Information System (INIS)

    The prime objective of radioactive waste treatment in nuclear industry is to minimize the waste volume by efficient process without generating secondary radioactive waste for its final disposal. Among the currently available technologies, for separation and recovery of metal ions, solvent extraction, ion-exchange, membrane based technologies and solid sorbent materials are more popular means. Though, all these technologies play major role in all the bulk separation processes, their marked limitations force the separation scientists to think of advance, more efficient and technically feasible alternatives. The extractant impregnated polymeric beads (EIMPBs), impregnated with metal-specific extractants, exhibit reliable separation performances under column operation, and hence bridge the gap between solvent extraction and ion exchange techniques. In the present work, PC88A impregnated PES beads are prepared and the sorption of Am (III) from aqueous waste solutions is investigated. The synthesized EIMPBs were characterized by FTIR, TGA and SEM techniques. The physiochemical strength of the beads was found to be excellent. The sorption study of Am (III), using these beads, was carried out by batch equilibration method and the effect of various parameters, like pH, equilibration time, Am (III) concentration, etc., on the sorption process, was investigated. The synthesized polymeric beads presented fairly higher sorption capacity for Am (III) at pH 3. The kinetics of extraction is very fast. The saturation of sorption is achieved in about 60 minutes of equilibration. The sorption kinetics data fits well in the pseudo second-order model, indicating that the sorption is dominated by chemisorptions. The sorption of Am (III) is observed to follow Langmuir isotherm and the monolayer capacity was calculated as 2.498 mg/g. The quantitative stripping of the extracted Am (III) can be achieved by using 0.1M oxalic acid. The blank polymeric beads, without PC88A,have shown negligible sorption of Am (III) under the similar experimental conditions

  14. Americium and plutonium release behavior from irradiated mixed oxide fuel during heating

    International Nuclear Information System (INIS)

    The release behavior of Pu and Am was investigated under the reducing atmosphere expected in sodium cooled fast reactor severe accidents. Irradiated Pu and U mixed oxide fuels were heated at maximum temperatures of 2773 K and 3273 K. EPMA, γ-ray spectrometry and α-ray spectrometry for released and residual materials revealed that Pu and Am can be released more easily than U under the reducing atmosphere. The respective release rate coefficients for Pu and Am were obtained as 3.11 × 10−4 min−1 and 1.60 × 10−4 min−1 at 2773 K under the reducing atmosphere with oxygen partial pressure less than 0.02 Pa. Results of thermochemical calculations indicated that the main released chemical forms would likely be PuO for Pu and Am for Am under quite low oxygen partial pressure

  15. Kinetics of the oxidation-reduction reactions of uranium, neptunium, plutonium, and americium in aqueous solutions

    International Nuclear Information System (INIS)

    This is a review with about 250 references. Data for 240 reactions are cataloged and quantitative activation parameters are tabulated for 79 of these. Some empirical correlations are given. Twelve typical reactions are discussed in detail, along with the effects of self-irradiation and ionic strength. (U.S.)

  16. Americium and plutonium separation by extraction chromatography for determination by accelerator mass spectrometry.

    Science.gov (United States)

    Kazi, Zakir H; Cornett, Jack R; Zhao, Xaiolei; Kieser, Liam

    2014-06-01

    A simple method was developed to separate Pu and Am using single column extraction chromatography employing N,N,N',N'-tetra-n-octyldiglycolamide (DGA) resin. Isotope dilution measurements of Am and Pu were performed using accelerator mass spectrometry (AMS) and alpha spectrometry. For maximum adsorption Pu was stabilized in the tetra valent oxidation state in 8M HNO3 with 0.05 M NaNO2 before loading the sample onto the resin. Am(III) was adsorbed also onto the resin from concentrated HNO3, and desorbed with 0.1 M HCl while keeping the Pu adsorbed. The on-column reduction of Pu(IV) to Pu(III) with 0.02 M TiCl3 facilitated the complete desorption of Pu. Interferences (e.g. Ca(2+), Fe(3+)) were washed off from the resin bed with excess HNO3. Using NdF3, micro-precipitates of the separated isotopes were prepared for analysis by both AMS and alpha spectrometry. The recovery was 97.7±5.3% and 95.5±4.6% for (241)Am and (242)Pu respectively in reagents without a matrix. The recoveries of the same isotopes were 99.1±6.0 and 96.8±5.3% respectively in garden soil. The robustness of the method was validated using certified reference materials (IAEA 384 and IAEA 385). The measurements agree with the certified values over a range of about 1-100 Bq kg(-1). The single column separation of Pu and Am saves reagents, separation time, and cost. PMID:24856406

  17. Pressure-induced changes in the electronic structure of americium metal

    International Nuclear Information System (INIS)

    We have conducted electronic-structure calculations for Am metal under pressure to investigate the behavior of the 5f-electron states. Density-functional theory (DFT) does not reproduce the experimental photoemission spectra for the ground-state phase where the 5f electrons are localized, but the theory is expected to be correct when 5f delocalization occurs under pressure. The DFT prediction is that peak structures of the 5f valence band will merge closer to the Fermi level during compression indicating presence of itinerant 5f electrons. Existence of such 5f bands is argued to be a prerequisite for the phase transitions, particularly to the primitive orthorhombic AmIV phase, but does not agree with modern dynamical-mean-field theory (DMFT) results. Our DFT model further suggests insignificant changes of the 5f valence under pressure in agreement with recent resonant x-ray emission spectroscopy, but in contradiction to the DMFT predictions. The influence of pressure on the 5f valency in the actinides is discussed and is shown to depend in a non-trivial fashion on 5f band position and occupation relative to the spd valence bands.

  18. Neutron capture and neutron-induced fission experiments on americium isotopes with DANCE

    Energy Technology Data Exchange (ETDEWEB)

    Jandel, Marian [Los Alamos National Laboratory

    2008-01-01

    Neutron capture cross section data on Am isotopes were measured using the Detector for Advanced Neutron Capture Experiments (DANCE) at Los Alamos National Laboratory. The neutron capture cross section was determined for {sup 241}Am for neutron energies between thermal and 320 keV. Preliminary results were also obtained for {sup 243}Am for neutron energies between 35 eV and 200 keV. The results on concurrent neutron-induced fission and neutron-capture measurements on {sup 242m}Am will be presented, where the fission events were actively triggered during the experiments. In these experiments, the Parallel-Plate Avalanche Counter (PPAC) detector that surrounds the target located in the center of the DANCE array was used as a fission-tagging detector to separate (n,{gamma}) from (n,f) events. The first evidence of neutron capture on {sup 242m}Am in the resonance region in between 2 and 9 eV of the neutron energy was obtained.

  19. 1976 Hanford americium-exposure incident: histologic and autoradiographic observations on skin

    International Nuclear Information System (INIS)

    Examination of biopsies from exposed and relatively unexposed areas of the face revealed changes that were consistent with actinic elastic degeneration associated with solar exposure, except in the areas in which sources of alpha radiation were detected in the upper dermis. In those areas particles judged to be ion exchange resin were found within a few macrophages and extracellularly among connective tissue fibers. Elastic fibers in those areas showed more advanced degenerative change than fibers not closely associated with heavy concentrations of alpha radiation

  20. 1976 Hanford americium-exposure incident: urinary excretion of trace metals during DTPA treatments

    International Nuclear Information System (INIS)

    Urine samples from a person treated intravenously with diethylenetriaminepentaacetate (DPTA) salts for 3 years to promote the excretion of 241Am were assayed for 24 elements including almost all of the trace metals currently recognized as essential for good health. Zinc was found to be the only metal excreted more rapidly than normal. An 18-mg urinary loss of body zinc was found to be associated with each 1-g injection of Na3CaDTPA. Use of either Na3ZnDTPA or Na3CaDTPA combined with oral dosages of ZnSO4 appeared to completely compensate for this loss, and it is unlikely that the patient experienced any zinc deficiency due to the DTPA treatment

  1. Optimization of an analytical method using extraction chromatography for the determination of plutonium, americium and curium in soil samples; Optimierung eines extraktionschromatographischen Analyseverfahrens zur Bestimmung von Plutonium, Americium und Curium in Bodenproben

    Energy Technology Data Exchange (ETDEWEB)

    Gann, Cordula

    2000-09-01

    An analytical method for determination of the actinides {sup 238}Pu, {sup 239+240}Pu, {sup 241}Am and {sup 244}Cm in soil samples was developed and optimized to allow specific immission measurements of radionuclides in the vicinity of the recently constructed radwaste facility at Wuerenlingen/Switzerland. Following a rapid extraction from the soil sample, as well as a preconcentration step via calcium oxalate precipitation, the actinides are separated using extraction chromatography. Separation of the actinides is carrie out applying the specific resins U/TEVA, TRU and TEVA (Eichrom Technologies IL/USA) and the anion exchange resin BioRAD 1-X2. Measurements are then performed using an {alpha}-spectrometer equipped with ion-implanted silicon charged particle detectors. For counting times of less than three days a detection limit of less than 0.05 Bq/kg is obtained for the actinides {sup 238}Pu, {sup 239+240}Pu, {sup 241}Am and {sup 244}Cm. (author) [German] Im Rahmen von Immissionsmessungen auf den Radionuklidgehalt in der Umgebung des kuerzlich erbauten Zwischenlagers Wuerenlingen wurde eine Analysenmethode zur Bestimmung der Aktivitaetskonzentration der Aktiniden {sup 238}Pu, {sup 239+240}Pu, {sup 241}Am und {sup 244}Cm in Bodenproben entwickelt und optimiert. Die Aktiniden werden nach einer kurzen Extraktion der Bodenprobe und einer Vorkonzentration durch eine Calciumoxalatfaellung mittels Extraktionschromatographie separiert. Die Bodenprobe durchlaeuft mehrere Trennungsschritte ueber die Austauscherharze U/TEVA, TRU und TEVA der Firma Eichrom (Illinois, USA) sowie eine zusaetzliche Abtrennung mit dem Harz BioRAD 1-.X2. Die Aktivitaet wird anschliessend ueber die {alpha}-Spektrometrie mit ionen-implantierten Siliziumdetektoren bestimmt. Eine Nachweisgrenze von 0.05 Bq/kg wird fuer die Aktiniden {sup 238}Pu, {sup 239+240}Pu, {sup 241}Am und {sup 244}Cm mit Messzeiten von weniger als drei Tagen im {alpha}-Spektrometer probemlos unterschritten. (Autorin)

  2. Speciation of plutonium and americium in the soils affected by Kraton-3 accidental underground nuclear explosion in Yakutia (Russia)

    International Nuclear Information System (INIS)

    In calcareous soils from Yakutia only 0.1 % or less 239Pu and 241Am exist in water-soluble form, i.e., the mobility of these radionuclides is relatively low. In the top humus-containing layer (0-4 cm) 239Pu and 241Am are distributed uniformly between organic and inorganic soil components. In the bottom soil layer (20-30 cm) the radionuclides are present mainly in inorganic soil components. The estimation of the radionuclide mobility demonstrates that 241Am is potentially a more mobile element than 239Pu. In the considered calcareous soils collected from the top layer 239Pu and 241Am exist both in humic and fulvic acids (FA). 241Am is much stronger bound to the group of mobile FA than 239Pu. In the bottom soil layer 239Pu and 241Am have been found mainly in FA. (author)

  3. Radiocaesium, plutonium and americium partitioning and solid speciation in sized, inter-tidal sediments from Strangford Lough

    International Nuclear Information System (INIS)

    Fine-grained surface (0-2 cm) sediment was collected at an inter-tidal site (Mahee Island) in Strangford Lough, on the NE coast of Ireland in September 1997. The sediment was wet-sieved into standard sized fractions using Endecott test sieves and the fractions assayed for 137Cs, 239,240Pu and 241Am content. Sub-samples of each fraction were measured with a Malvern 2600 laser diffraction analyser, which confirmed that >90% of the particles in each fraction was in the defined size range

  4. The determination of americium, curium and californium in biological samples by combined solvent extraction-liquid scintillation counting

    International Nuclear Information System (INIS)

    A method has been developed to extract Am, Cm and Cf from ashed biological samples dissolved in 8 M LiN03-10-2 M HN03 into a liquid/scintillation cocktail. This new method reduces tissue and instrument background and allows use of a larger sample for analysis than when using a commercial gelling cocktail. The extractant cocktail is 20% N,N,N-trioctyl-N-methylammonium chloride dissolved in toluene containing the scintillators p-terphenyl and 1,4-bis-2-(5-phenyl-oxazolyl)-benzene. Several different types of biological samples were analyzed and radionuclide recoveries greater than 90% were obtained in all cases. (author)

  5. Oxidation-reduction properties of americium, curium, berkelium, californium, einsteinium and fermium, and thermodynamic consequences for the 5f series

    International Nuclear Information System (INIS)

    The amalgamation of 5f elements from Am to Fm has been studied by using 241Am, 244Cm, 249Bk, 249Cf, 252Cf, 253Es, 254Es, 252Fm and 255Fm with two electrochemical methods, radiocoulometry and radiopolarography, perfectly adapted to investigate extremely diluted solutions when the concentration of electroactive species is as low as 10-16M. The theory of radiocoulometry has been developed in the general cases of reversible and irreversible electrode process. It has been used to interpret the experimental data on the kinetic curves of amalgamation, and to estimate the standard rate constant of the electrode process in complexing medium (citric). On the other hand the radiopolarographic method has been applied to study the mechanism of reduction at the dropping mercury electrode of cations M3+ in aqueous medium to the metal M with formation of amalgam. The results are exploited into two directions: 1- Acquisition of some data concerning the oxidation-reduction properties of elements from Am to Fm. Therefore the standard electrode E0 [M(III-0)] potentials for Bk, Cf and Es, and the standard electrode E0 [M(II-0)] potential for Fm are estimated and the relative stability of each oxidation state (from II to VII) of 5f elements is discussed; 2- Acquisition of unknown thermodynamic data on transcalifornium elements. Correlations between 4f and 5f elements are precised and some divergences appear for the second half of 4f and 5f series (i.e. for 65<=Z<=71 and 97<=Z<=103)

  6. Effects of americium-241 and humic substances on Photobacterium phosphoreum: Bioluminescence and diffuse reflectance FTIR spectroscopic studies

    Science.gov (United States)

    Kamnev, Alexander A.; Tugarova, Anna V.; Selivanova, Maria A.; Tarantilis, Petros A.; Polissiou, Moschos G.; Kudryasheva, Nadezhda S.

    The integral bioluminescence (BL) intensity of live Photobacterium phosphoreum cells (strain 1883 IBSO), sampled at the stationary growth stage (20 h), was monitored for further 300 h in the absence (control) and presence of 241Am (an α-emitting radionuclide of a high specific activity) in the growth medium. The activity concentration of 241Am was 2 kBq l-1; [241Am] = 6.5 × 10-11 M. Parallel experiments were also performed with water-soluble humic substances (HS, 2.5 mg l-1; containing over 70% potassium humate) added to the culture medium as a possible detoxifying agent. The BL spectra of all the bacterial samples were very similar (λmax = 481 ± 3 nm; FWHM = 83 ± 3 nm) showing that 241Am (also with HS) influenced the bacterial BL system at stages prior to the formation of electronically excited states. The HS added per se virtually did not influence the integral BL intensity. In the presence of 241Am, BL was initially activated but inhibited after 180 h, while the system 241Am + HS showed an effective activation of BL up to 300 h which slowly decreased with time. Diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy, applied to dry cell biomass sampled at the stationary growth phase, was used to control possible metabolic responses of the bacteria to the α-radioactivity stress (observed earlier for other bacteria under other stresses). The DRIFT spectra were all very similar showing a low content of intracellular poly-3-hydroxybutyrate (at the level of a few percent of dry biomass) and no or negligible spectroscopic changes in the presence of 241Am and/or HS. This assumes the α-radioactivity effect to be transmitted by live cells mainly to the bacterial BL enzyme system, with negligible structural or compositional changes in cellular macrocomponents at the stationary growth phase.

  7. Separation of americium, curium, and rare earths from high-level wastes by oxalate precipitation: experiments with synthetic waste solutions

    International Nuclear Information System (INIS)

    The separation of trivalent actinides and rare earths from other fission products in high-level nuclear wastes by oxalate precipitation followed by ion exchange (OPIX) was experimentally investigated using synthetic wastes and a small-scale, continuous-flow oxalic acid precipitation and solid-liquid separation system. Trivalent actinide and rare earth oxalates are relatively insoluble in 0.5 to 1.0 M HNO3 whereas other fission product oxalates are not. The continuous-flow system consisted of one or two stirred-tank reactors in series for crystal growth. Oxalic acid and waste solutions were mixed in the first tank, with the product solid-liquid slurry leaving the second tank. Solid-liquid separation was tested by filters and by a gravity settler. The experiments determined the fraction of rare earths precipitated and separated from synthetic waste streams as a function of number of reactors, system temperature, oxalic acid concentration, liquid residence time in the process, power input to the stirred-tank reactors, and method of solid-liquid separation. The crystalline precipitate was characterized with respect to form, size, and chemical composition. These experiments are only the first step in converting a proposed chemical flowsheet into a process flowsheet suitable for large-scale remote operations at high activity levels

  8. A Review of Subsurface Behavior of Plutonium and Americium at the 200-PW-1/3/6 Operable Units

    Energy Technology Data Exchange (ETDEWEB)

    Cantrell, Kirk J.; Riley, Robert G.

    2008-01-31

    This report begins with a brief summary of the history and current status of 200-PW-1/3/6 OUs in section 2.0. This is followed by a description of our concentual model of Pu/Am migration at the 200-PW-1/3/6 OUs, during both past artificial recharge conditions and current natural recharge condictions (section 3.0). Section 4.0 discusses data gaps and information needs. The final section (section 5.0) provides recommendations for futher work to address the data gaps and information needs identified in section 4.0.

  9. Evaluation of synthetic water-soluble metal-binding polymers with ultrafiltration for selective concentration of americium and plutonium

    International Nuclear Information System (INIS)

    Water-soluble metal-binding polymers in combination with ultrafiltration are shown to be an effective method for selectively removing dilute actinide ions from acidic solutions of high ionic strength. The actinide-binding properties of commercially available water-soluble polymers and several polymers which have been reported in the literature were evaluated. The functional groups incorporated in the polymers were pyrrolidone, amine, oxime, and carboxylic, phosphonic, or sulfonic acid. The polymer containing phosphonic acid groups gave the best results with high distribution coefficients and concentration factors for 241Am(III) and 238Pu(III)/(IV) at pH 4 to 6 and ionic strengths of 0.1 to 4. (author)

  10. The determination of alpha-emitting nuclides of plutonium, americium and curium in environmental materials: Pt. 1

    International Nuclear Information System (INIS)

    Within the Aquatic Environment Protection Division of the Directorate of Fisheries Research (DFR), the Radioanalytical Group routinely analyses a wide range of environmental materials for a substantial number of radionuclides. A wide variety of radiochemical procedures have been developed at different laboratories but there are no 'standard' methods because the methods are continually developing. Nevertheless, it is useful, as in this present series, periodically to draw together the methods which are in routine use at a laboratory and to discuss their development and application. (author)

  11. Rate and mechanism of facilitated americium(III) transport through a supported liquid membrane containing a bifunctional organophosphorus mobile carrier

    International Nuclear Information System (INIS)

    The facilitated transport of Am(III) from aqueous nitrate solutions to formic acid aqueous solutions through a supported liquid membrane (SLM) is described. The supported liquid membrane consists of a solution of a new (carbamoylmethyl)phosphine oxide in diethylbenzene (DEB) absorbed into a 48 μm thick microporous polypropylene film. The transport mechanism consists of a diffusion process through an aqueous diffusion film, a fast interfacial chemical reaction, and diffusion through the membrane itself. Equations describing the rate of transport are derived. They correlate the membrane permeability coefficient to diffusional parameters and to the chemical composition of the system. Different rate-controlling processes are shown to control the membrane permeability when the composition of the system is varied and as long as the transport occurs. The experimental data are quantitatively explained with the derived equations. The diffusion coefficient of the permeating species and the equilibrium constant of the fast interfacial reactions are evaluated. 13 figures, 1 table

  12. Studies on the binding and transport processes of americium-241 hydroxide polymers in rat lung and bovine alveolar macrophages

    International Nuclear Information System (INIS)

    The binding of Am-241 hydroxide polymers to the cell components of rat lung was investigated using differential centrifugation, density gradient centrifugation with different media, gel chromatography, free flow electrophoresis and electron microscopic autoradiography with Pu-241. The bovine alveolar macrophage cultures were introduced as an in vitro test system for Am-241 uptake. Form the biochemical and electron microscopic studies it can be concluded that Am-241 is taken up by pulmonary macrophages, where its first storage site is probably the lysosome. Then the Am-241 seems to be solubilized in the lysosomes and to be bound to the cytosolic ferritin of macrophages. Am-241 might be released from the cells and crosses the alveolar membranes as bound to transferrin or as low molecular weight form. (orig.)

  13. Assessment of americium and curium transmutation in magnesia based targets in different spectral zones of an experimental accelerator driven system

    Science.gov (United States)

    Haeck, W.; Malambu, E.; Sobolev, V. P.; Aït Abderrahim, H.

    2006-06-01

    The potential to incinerate minor actinides (MA) in a sub-critical accelerator-driven system (ADS) is a subject of study in several countries where nuclear power plants are present. The performance of the MYRRHA experimental ADS, as to the transmutation of Am and Cm in the inert matrix fuel (IMF) samples consisting of 40 vol.% (Cm0.1Am0.5Pu0.4)O1.88 fuel and 60 vol.% MgO matrix with a density of 6.077 g cm-3 in three various spectrum regions, were analysed at the belgian nuclear research centre SCK · CEN. The irradiation period of 810 effective full power days (EFPD) followed by a storage period of 2 years was considered. The ALEPH code system currently under development at SCK · CEN was used to carry out this study. The total amount of MA is shown to decrease in all three considered cases. For Am, the decrease is the largest in the reflector (89% decrease) but at the cost of a net Cm production (92% increase). In the two other positions (inside the core region), 20-30% of Am has disappeared but with a lower production of Cm (between 7% and 11%). In the reflector, a significant build-up of long-lived 245Cm, 246Cm, 247Cm and 248Cm was also observed while the production of these isotopes is 10-1000 times smaller in the core. The reduction of the Pu content is also the highest in the reflector position (41%). In the other positions the incinerated amount of Pu is much smaller: 1-5%.

  14. LITERATURE REVIEW ON THE SORPTION OF PLUTONIUM, URANIUM, NEPTUNIUM, AMERICIUM AND TECHNETIUM TO CORROSION PRODUCTS ON WASTE TANK LINERS

    Energy Technology Data Exchange (ETDEWEB)

    Li, D.; Kaplan, D.

    2012-02-29

    The Savannah River Site (SRS) has conducted performance assessment (PA) calculations to determine the risk associated with closing liquid waste tanks. The PA estimates the risk associated with a number of scenarios, making various assumptions. Throughout all of these scenarios, it is assumed that the carbon-steel tank liners holding the liquid waste do not sorb the radionuclides. Tank liners have been shown to form corrosion products, such as Fe-oxyhydroxides (Wiersma and Subramanian 2002). Many corrosion products, including Fe-oxyhydroxides, at the high pH values of tank effluent, take on a very strong negative charge. Given that many radionuclides may have net positive charges, either as free ions or complexed species, it is expected that many radionuclides will sorb to corrosion products associated with tank liners. The objective of this report was to conduct a literature review to investigate whether Pu, U, Np, Am and Tc would sorb to corrosion products on tank liners after they were filled with reducing grout (cementitious material containing slag to promote reducing conditions). The approach was to evaluate radionuclides sorption literature with iron oxyhydroxide phases, such as hematite ({alpha}-Fe{sub 2}O{sub 3}), magnetite (Fe{sub 3}O{sub 4}), goethite ({alpha}-FeOOH) and ferrihydrite (Fe{sub 2}O{sub 3} {center_dot} 0.5H{sub 2}O). The primary interest was the sorption behavior under tank closure conditions where the tanks will be filled with reducing cementitious materials. Because there were no laboratory studies conducted using site specific experimental conditions, (e.g., high pH and HLW tank aqueous and solid phase chemical conditions), it was necessary to extend the literature review to lower pH studies and noncementitious conditions. Consequently, this report relied on existing lower pH trends, existing geochemical modeling, and experimental spectroscopic evidence conducted at lower pH levels. The scope did not include evaluating the appropriateness of K{sub d} values for the Fe-oxyhydroxides, but instead to evaluate whether it is a conservative assumption to exclude this sorption process of radionuclides onto tank liner corrosion products in the PA model. This may identify another source for PA conservatism since the modeling did not consider any sorption by the tank liner.

  15. Solvent phase characterization of lanthanide and americium complexes with malonamide and ter-pyridine ligands. Comparison with single crystals

    Energy Technology Data Exchange (ETDEWEB)

    Den Auwer, C.; Grigoriev, M.S.; Charbonnel, M.C.; Presson, M.T. [CEA/VALRHO - site de Marcoule, Dept. de Recherche en Retraitement et en Vitrification, DRRV, 30 - Marcoule (France); Den Auwer, C. [Laboratoire pour l' Utilisation du Rayonnement Electromagnetique (LURE), Paris-11 Univ., 91 - Orsay (France); Grigoriev, M.S. [Institute of Physical Chemistry, Russian Academy of Sciences, Moscow (Russian Federation)

    2000-07-01

    This work presents our latest results on the coordination polyhedron of the tetranitrate lanthanide complexes with aza and carboxy ligands. Structures in the solid state have been determined by X-ray single crystal diffraction and solution studies have been carried out by X-ray Absorption Spectroscopy at the cation L{sub III} edge. Comparison is made with the Am cation. (authors)

  16. Solvent phase characterization of lanthanide and americium complexes with malonamide and ter-pyridine ligands. Comparison with single crystals

    International Nuclear Information System (INIS)

    This work presents our latest results on the coordination polyhedron of the tetranitrate lanthanide complexes with aza and carboxy ligands. Structures in the solid state have been determined by X-ray single crystal diffraction and solution studies have been carried out by X-ray Absorption Spectroscopy at the cation LIII edge. Comparison is made with the Am cation. (authors)

  17. Simultaneous separation and purification of plutonium and americium from aqueous nitrate solutions using extractant impregnated macroporous polymeric beads

    International Nuclear Information System (INIS)

    The removal of Pu(IV) and Am(III) ions from aqueous nitrate solutions was studied using indigenously synthesized Extractant Impregnated Macroporous Polymeric Beads (EIMPBs). These beads exhibited almost quantitative sorption of Pu(IV) at acid strength of >2 M HNO3 while that of Am(III) at pH 3. Langmuir sorption model was found suitable, with the sorption capacity of EIMPBs for Pu(IV) and Am(III) as 2.13 and 2.64 mg g-1 respectively. Its performance remained unchanged until seven cycles of extraction and stripping using 0.1 M oxalic acid. A flow sheet for Purification of Pu(IV)/Am(III) from its mixture is proposed. (author)

  18. Effects of Hanford high-level waste components on the solubility and sorption of cobalt, strontium, neptunium, plutonium, and americium

    International Nuclear Information System (INIS)

    High-level radioactive defense waste solutions, originating from plutonium recovery and waste processing operations at the U.S. Department of Energy's Hanford Site, currently are stored in mild steel-lined concrete tanks located in thick sedimentary beds of sand and gravel. Statistically designed experiments were used to identify the effects of 12 major chemical components of Hanford waste solution on radionuclide solubility and sorption. The chemical components with the most effect on radioelement solubility and sorption were NaOH, NaAl0/sub 2/, EDTA, and HEDTA. The EDTA and HEDTA increased Co, Sr, and Am solubility and decreased sorption for almost all radioelements studied. Sodium hydroxide and NaAlO/sub 2/ increased Pu solubility and decreased Np and Pu sorption. Sodium nitride decreased Np solubility, while Na/sub 2/CO/sub 3/ and HEDTA increased it. These observations give evidence for the formation of radioelement complexes which are soluble and are not strongly sorbed by the sediments near the waste tanks

  19. Extraction of americium and light rare earths by 2-ethyl hexyl phosphonic acid 2-ethyl hexyl ester

    International Nuclear Information System (INIS)

    The extraction behavior of trace Am(III) and Eu(III) from nitrate medium with HEHEHP in kerosene was studied. LgD/pH and lgD/[H2A2] dependence plots are given. Calculated values of lgKex for Eu, Nd and Am are -0.13+-0.08, -1.36+-0.10, -1.89+-0.18, respectively. Extraction equilibrium equations were deduced under proper conditions. Calculated values of DAm and DRE are in accordance with experimental ones

  20. Study of plutonium and americium contamination in agricultural area, radiological impact caused by consumption of vegetables of this area

    International Nuclear Information System (INIS)

    The transuranide concentration has been studied for 30 years in vegetable production, crops in wide extensions and in private-owned farms, all of them situated within the Pu-contaminated area of Palomares due to an air accident in 1966. Based on these studies, a preliminary estimation of the radiological risk caused by the consumption of these products by the inhabitants was possible. The results show that most of the fruits present a surface contamination, which disappears or is significantly reduced when they are washed. The contamination present in edible parts of the vegetables, as well as the contamination of other products included in the diet, has facilitated the estimation of the effective dose for ingestion and the committed effective dose for 50 years for the inhabitants. The main conclusions are: those plants, whose cultivation period is less than a year, present a low level of contamination; the green parts of the plants have a higher contamination than the fruits; the Pu soil to plant transfer factor is very low. In general, those plants that have remained in the contaminated land for several years present a high contamination level; the ingestion of products from Palomares does not represent an important risk for the population, even in the case that the products were totally consumed by a critical group.( author)

  1. Geographic and vertical distribution of global fallout americium 241, plutonium isotopes and cesium 137 in lake sediments

    International Nuclear Information System (INIS)

    In this study, we present results concerning the activity concentrations of 241Am, 239-240Pu, 238Pu and 137Cs in lake sediments. Bulk cores for radionuclide inventories and high resolution cores for depth distribution are analysed

  2. Salicylic acid failed to increase the efficacy of Ca-DTPA in the decorporation of plutonium and americium

    International Nuclear Information System (INIS)

    Male and female C57BL/Do mice were each given a single i.p. injection of 237+239Pu + 241Am as the citrate complex at 45 days of age. Twice weekly i.p. injecctions of either 500 μmol/kg Ca-DTPA or 500 μmol/kg Ca-DTPA, mixed just before injection with 2000 μmol/kg salicylic acid (SA), were begun 3 days after nuclide administration and continued for 5 weeks. Control mice were injected each time with isotonic saline. Nuclide retention was determined by in vivo counting using NaI(T1) spectrometry. At the end of treatment, total-body retention of Pu or Am in the mice given Ca-DTPA was significantly lower (P < 0.001) than in the control animals. Mice treated with Ca-DTPA + SA were statistically indistinguishable from mice treated with Ca-DTPA

  3. Salicylic acid failed to increase the efficacy of Ca-DTPA in the decorporation of plutonium and americium

    International Nuclear Information System (INIS)

    Male and female C57BL/Do mice were each given a single ip injection of /sup 237 + 239/Pu + 241Am as the citrate complex at 45 days of age. Twice-weekly ip injections of either 500 μmole/kg Ca-DTPA or 500 μmole/kg Ca-DTPA mixed just before injection with 2000 μmole/kg salicylic acid (SA) were begun 3 days after nuclide administration and continued for 5 weeks. Control mice were injected each time with isotonic saline. Nuclide retention was determined by in vivo γ-ray counting using a NaI(Tl) crystal spectrometer. At the end of treatment, total-body retention of Pu or Am in the mice given Ca-DTPA was significantly lower (P < 0.001) than that in the control animals. Mice treated with Ca-DTPA plus SA were statistically indistinguishable from mice treated with Ca-DTPA alone

  4. Handling of a glove box accident. Surgical treatment of a wound contaminated by a mixture of plutonium-239 and americium

    International Nuclear Information System (INIS)

    An employee of the Valduc Centre (France) suffered an injury to his right thumb when working in a glove-box on a pipeline which had contained a solution of 239Pu and Am. The lesion was slight but attempts at decontamination were fruitless. The contamination was deep-seated (activity of not less than 18nCi). DTPA was injected intravenously, and it was decided to excise the lesion surgically. Thanks to the quality of its physical facilities and the professional quality of its radiation medicine and surgery team, the Valduc Centre was able to carry out the operation successfully. The result was excellent, and the contamination was eliminated to the satisfaction of both the patient and the physician. (author)

  5. Optimization of an analytical method using extraction chromatography for the determination of plutonium, americium and curium in soil samples

    International Nuclear Information System (INIS)

    An analytical method for determination of the actinides 238Pu, 239+240Pu, 241Am and 244Cm in soil samples was developed and optimized to allow specific immission measurements of radionuclides in the vicinity of the recently constructed radwaste facility at Wuerenlingen/Switzerland. Following a rapid extraction from the soil sample, as well as a preconcentration step via calcium oxalate precipitation, the actinides are separated using extraction chromatography. Separation of the actinides is carrie out applying the specific resins U/TEVA, TRU and TEVA (Eichrom Technologies IL/USA) and the anion exchange resin BioRAD 1-X2. Measurements are then performed using an α-spectrometer equipped with ion-implanted silicon charged particle detectors. For counting times of less than three days a detection limit of less than 0.05 Bq/kg is obtained for the actinides 238Pu, 239+240Pu, 241Am and 244Cm. (author)

  6. Concentration and speciation of plutonium, americium, uranium, thorium, potassium and 137Cs in a venice canal sediment sample

    Science.gov (United States)

    Testa, C.; Desideri, D.; Guerra, F.; Meli, M. A.; Roselli, C.; Degetto, S.

    1999-01-01

    A sequential extraction method consisting of six operationally-defined fractions has been developed for determining the geochemical partitioning of natural (U, Th, 40K) and antropogenic (Pu, Am, 137Cs) radionuclides in a 40-50 cm deep sediment sample collected in a Venice canal. Extraction chromatography with Microthene-TOPO (U, Th), Microthene-TNOA (Pu) and Microthene-HDEHP (Am) column was used for the chemical separation of a single radionuclide; the final recoveries were calculated by adding 236U, 229Th, 242Pu and 243Am as the yield tracers. After electrodeposition the alpha spectrometry was carried out. 137Cs and 40K were measured by gamma spectrometry. The total concentrations in the wet sample (Bq/kgd), obtained by a complete disgregation of the matrix by wet and dry treatment, were the following: 239+240Pu=1.03±0.07, 238Pu=0.022±0.005, 241Am=0.337±0.027, 137Cs=9.78±0.78, 238U=28.84±1.62, 232Th=21.42±1.93, 40K=376.05±12.78. The mean ratio 238Pu/239+240Pu (0.02) shows a contamination due essentially to fall-out and U and Th alpha spectra indicate the natural origin of two elements. The absence of 134Cs in the sample proves that at 40-50 cm depth the sediment was not affected by the Chernobyl fall-out. As far as the speciation is concerned the following fractions were considered: water soluble, carbonates, Fe-Mn oxides, organic matter, acid soluble, residue. Pu (˜67%) an Am (˜95%) were present principally in the carbonate fraction; U was more distributed and about 30% and 45% appeared in the carbonate fraction and in the residue respectively; the majority of Th was present in the residue (˜60%); 40K was totally present in the residue; finally 137Cs was found mostly in the acid soluble fraction (˜53%) and in the residue (˜47%). Some stable elements (Fe, Mn, Al, Ti, Ca, Pb, Ba) were also determined in the different fractions to get more information about the chemical association of the single radionuclides.

  7. A Review of Subsurface Behavior of Plutonium and Americium at the 200-PW-1/3/6 Operable Units

    International Nuclear Information System (INIS)

    This report begins with a brief summary of the history and current status of 200-PW-1/3/6 OUs in section 2.0. This is followed by a description of our conceptual model of Pu/Am migration at the 200-PW-1/3/6 OUs, during both past artificial recharge conditions and current natural recharge conditions (section 3.0). Section 4.0 discusses data gaps and information needs. The final section (section 5.0) provides recommendations for further work to address the data gaps and information needs identified in section 4.0

  8. Determination of plutonium, uranium and americium/curium isotopes in environmental samples with anion exchange, UTEVA, Sr and DGA resin

    International Nuclear Information System (INIS)

    This study presents a quantitative sequential radiochemical separation method for the Pu, U, Sr and Am/Cm isotopes with an anion exchange resin, UTEVA resin, Sr resin and DGA resin in environmental samples. After the radionuclides were leached from samples with 8M HNO3, the Pu, U, Sr and Am/Cm isotopes were sequentially adsorbed on the anion exchange column, UTEVA column connected with Sr Spec column and DGA column. The Pu isotopes were purified from other nuclides through the anion exchange column, and the uranium isotopes were separated from other nuclides through the UTEVA column. Also, 90Sr was separated from other hindrance elements such as Ca2+, Ba2+ and Y3+ with the Sr Spec column. Finally, Am/Cm fractions were purified with the DGA and anion exchange resins. After α source preparation for the purified Pu, U and Am/Cm isotopes with the micro-coprecipitation method, the Pu, U and Am/Cm isotopes were measured by an alpha spectrometry. Strontium-90 was measured by a low level liquid scintillation counter. The radiochemical procedure for Pu, U and Am nuclides investigated in this study has been validated by application to IAEA Reference soils. (orig.)

  9. Evaluation of thermal neutron cross-sections and resonance integrals of protactinium, americium, curium, and berkelium isotopes

    International Nuclear Information System (INIS)

    Data on the thermal neutron fission and capture cross-sections as well as their corresponding resonance integrals are reviewed and analysed. The data are classified according to the form of neutron spectra under investigation. The weighted mean values of the cross-sections and resonance integrals for every type of neutron spectra were adopted as evaluated data. (author). 87 refs, 2 tabs

  10. Luminescence study on solvation of americium(III), curium(III) and several lanthanide(III) ions in nonaqueous and binary mixed solvents

    International Nuclear Information System (INIS)

    The luminescence lifetimes of An(III) and Ln(III) ions [An=Am and Cm; Ln=Nd, Sm, Eu, Tb and Dy] were measured in dimethyl sulfoxide(DMSO), N,N-dimethylformamide(DMF), methanol(MeOH), water and their perdeuterated solvents. Nonradiative decay rates of the ions were in the order of H2O > MeOH > DMF > DMSO, indicating that O-H vibration is more effective quencher than C-H, C=O, and S=O vibrations in the solvent molecules. Maximal lifetime ratios τD/τH were observed for Eu(III) in H2O, for Sm(III) in MeOH and DMF, and for Sm(III) and Dy(III) in DMSO. The solvent composition in the first coordination sphere of Cm(III) and Ln(III) in binary mixed solvents was also studied by measuring the luminescence lifetime. Cm(III) and Ln(III) were preferentially solvated by DMSO in DMSO-H2O, by DMF in DMF-H2O, and by H2O in MeOH-H2O over the whole range of the solvent composition. The order of the preferential solvation, i.e., DMSO > DMF > H2O > MeOH, correlates with the relative basicity of these solvents. The Gibbs free energy of transfer of ions from water to nonaqueous solvents was further estimated from the degree of the preferential solvation. (orig.)

  11. Removal of plutonium and americium from the rat using 3,4,3-LIHOPO and DTPA after simulated wound contamination: effect of delayed administration and mass of plutonium

    International Nuclear Information System (INIS)

    The comparative efficacies of treatment with 3,4,3-LIHOPO and DTPA have been investigated in the rat after their subcutaneous intramuscular injection. Commencement of treatment was delayed 30 min, 6 h or 1 d and the animals killed at 7 d. Under all conditions, 3,4,3-LIHOPO was considerably more effective than DTPA, although the efficacy of both ligands and their relative effectiveness decreased rapidly with their delay in administration. After early treatment of the intramuscular deposit of Pu and Am with 3,4,3-LIHOPO, the body content of Pu and Am was about 1% of those in untreated animals and about 30 times less than when using the same treatment regimen with DTPA. The value for Pu increased to 5% of controls when the amount deposited increased from 1.5 ng to 0.9 mg.kg-1 body mass. (author)

  12. The role of natural organic matter in the migration behaviour of americium in the Boom clay - Part II: analysis of migration experiments

    International Nuclear Information System (INIS)

    Full text of publication follows: In demonstrating the suitability of Boom Clay as a potential site for the disposal of radioactive waste in Belgium, the role of the relatively high amount of Natural Organic Matter (NOM) present in the Boom Clay on the mobility of critical radionuclides needs investigation. Trivalent actinides and lanthanides form strong complexes with humic substances. Complexation of these trivalent radionuclides with NOM present in the Boom Clay may have opposing effects. If complexed by the aqueous phase (mobile) NOM, radionuclide transport will be governed by the mobility of these dissolved radionuclide-NOM species. If complexed by the solid phase (immobile) NOM, migration will be retarded. One of the aims of the EC projects TRANCOM-Clay and TRANCOM-II was to investigate the role of mobile NOM as radionuclide carrier with the objective of deriving conceptual models that can be implemented in repository performance assessment (PA) models. A separate paper describes the results of column migration experiments involving the transport of 241Am-14C-NOM complexes through Boom Clay cores. This paper describes the transport model, POPCORN, that was developed to describe and evaluate the influence of NOM on radionuclide transport in clay, taking into account attachment/detachment rates of NOM to clay surfaces and the kinetics of RN complexation to, and destabilization from, NOM. The POPCORN model was used to evaluate diffusion experiments involving injection of 14C-labelled NOM in Boom Clay cores. Model fits were obtained by varying the rates of filtration of NOM by attachment to the surface of the clay matrix. POPCORN was then used to analyse the 241Am-14C-NOM migration experiments. The stability properties of the 241Am-NOM were characterised by kinetic constants, and good matches to the migration data were achieved for the experiments. The findings suggest that a small sub-population of the original 241Am-OM is the most stable, and that this sub-population has specific transport characteristics, including low dispersivity and a potential for filtering. Such characteristics may be representative of larger, more stable, but less mobile 241Am-OM complexes. In summary, the key processes governing 241Am migration are the rate of 241Am-OM destabilization and the rates of attachment and detachment of OM on the clay surfaces. Correlations between different transport parameters have been identified, and these findings offer means of extrapolating parameter values for application of the model to larger-scale problems. (authors)

  13. Methodology for the Inventory and Assessment of Americium Contamination Level in 1987 in an Area of Palomares Contaminated with Plutonium Weapon Grade

    International Nuclear Information System (INIS)

    This paper presents a methodology applied for the assessment of the ''241 Am coming from the decay of ''241 Pu isotope content in a contaminated area of Palomares, where the clean-up work done in 1966, given the negligible agricultural importance of such area at the time and its geographical characteristics, was not of the same magnitude as for the rest of the region. (Author) 4 refs

  14. DEVELOPMENT OF FUNDAMENTAL DATA ON CHEMICAL SPECIATION AND SOLUBILITY FOR STRONTIUM AND AMERICIUM IN HIGH LEVEL WASTE: PREDICTIVE MODELING OF PHASE PARTITIONING DURING TANK PROCESSING

    Science.gov (United States)

    Current strategies for reducing the total volume of radioactive tank waste requiring disposal at Hanford and other DOE sites call for the development of methods to selectively dissolve and remove non-radioactive elements such as Al, P, and Cr while retaining or precipitating the ...

  15. Americium(III) oxidation by copper(III) periodate in nitric acid solution as compared with the action of Bi(V) compounds of sodium, lithium, and potassium

    International Nuclear Information System (INIS)

    The oxidative action of a Cu(III) periodate compound toward Am(III) in nitric acid was studied. The extent of oxidation of Am(III) to Am(VI) was investigated using a constant initial Cu(III)-to-Am(III) molar ratio of 10:1 and varying nitric acid concentrations from 0.25 to 3.5 mol/L. From 0.25 to 3 mol/L HNO3, more than 98% of the Am(III) was oxidized to Am(VI); however, at 3.5 mol/L HNO3, the conversion to Am(VI) was only 80%. Increasing the Cu(III)-to-Am(III) molar ratio to 20:1 in 3.5 mol/L HNO3 resulted in 98% conversion to Am(VI). For comparison, oxidation of Am(III) with NaBiO3 was studied at 3.5 mol/L HNO3 and the same stoichiometric excess of Bi(V) oxidant over Am(III) (stoichiometric ratio of 3.33:1). With NaBiO3, the extent of Am(III) conversion to Am(VI) was only 19%, while with the Cu(III) compound this value was found to be about 4 times higher under otherwise identical conditions. Similar results were obtained with other Bi(V) salts. These results show that the Cu(III) periodate compound is a superior oxidant to NaBiO3, yielding rapid conversion to Am(VI) in a homogeneous acidic solution, and is, therefore, an excellent candidate for further development of Am separation systems.

  16. Solubility limits of radionuclides in interstitial water. Americium in cement. Task 3. Characterization of radioactive waste forms. A series of final reports (1985-89). No 34

    International Nuclear Information System (INIS)

    The migration of actinides inside cement (or concrete) is very slow, even when the material is saturated with water: precipitation of actinide hydroxide explains this retention phenomenon. The aim of this work is to measure Am solubility in aqueous solutions equilibrated with CPA55 cement to: (i) compare it with thermodynamic predictions; and (ii) correlate it to (future) migration measurements of Am through cement discs. 12 figs.; 8 tabs.; 3 refs

  17. Studies on the feasibility of using completely incinerable reagents for the single-cycle separation of americium(III) from simulated high-level liquid waste

    International Nuclear Information System (INIS)

    The extraction and stripping behavior of various metal ions present in the fast reactor simulated high-level liquid waste (FR-SHLLW) was studied using a solvent phase composed of a neutral extractant, N,N,-didodecyl-N',N'-dioctyl-3-oxapentane-1,5-diamide (D3DODGA) and an acidic extractant, di-2-ethylhexyl diglycolamic acid (HDEHDGA) in n-dodecane (n-DD). The third phase formation behavior of the solvent formulation D3DODGA + HDEHDGA/n-DD, was studied when it was contacted with FR-SHLLW, and the concentration of neutral and acidic extractant needed to avoid the third phase formation was optimized. The distribution ratio of various metal ions present in FR-SHLLW was measured in a solution of 0.1 M D3DODGA + 0.2 M HDEHDGA/n-DD. The extraction of Am(III) was accompanied by the co-extraction of lanthanides and unwanted metal ions such as Zr(IV), Y(III), and Pd(II). A procedure was developed to minimize the extraction of unwanted metal ions by using aqueous soluble complexing agents in FR-SHLLW. Based on those results, the counter-current mixer-settler run was performed in a 20-stage mixer-settler. Quantitative extraction of Am(III), Ln(III), Y(III), and Sr(II) in 0.1 M D3DODGA + 0.2 M HDEHDGA/n-DD was observed. The recovery of Am(III) from the loaded organic phase was carried out by the optimized aqueous formulation composed of 0.01 M diethylenetriaminepentaacetic acid (DTPA) + 0.5 M citric acid (CA) at pH 1.5. The stripping of Am(III) was accompanied by co-stripping of some early lanthanides. However the later lanthanides (Eu(III) and beyond) were not back extracted to Am(III) product. Therefore, the studies foresee the possibility of intra-lanthanides as well as lanthanide-actinide separation in a single-processing cycle.

  18. Sorption and diffusion of cobalt, strontium, cesium and americium in natural fissure surfaces and drill core cups studied by autoradiography, 1

    International Nuclear Information System (INIS)

    A method based on autoradiography was developed to determine the diffusion of radionuclides into the rock matrix. To investigate the diffusion the samples, which has been in contact with radioactive tracer solution up to 6 months, were splitted by sawing. From the autoradiograms of the cross sections the penetration depths of radionuclides were determined and the apparent diffusion coefficient Dsup(a) calculated. The filled and unfilled natural fissure surfaces chosen to this study were bars of drilling cores and drill core cups of tonalite, mica gneiss and rapakivi granite. After contact time of 3 months the highest penetration depths of cesium were observed for natural fissure surface sample of rapakivi granite up to 2.5 mm and of mica gneiss up to 3.7 mm. For strontium the penetration depths of 6 mm and 11 mm for unfilled and filled natural fissure samples of rapakivi granite were found. Dsup(a)-values for cesium varied between 1.5 x 10-15 and 3.2 x 10-14, for strontium between 3.5 x 10-14 and 2.1 x 10-13 m2/s. D-value obtained for cobalt (drill core cup sample, tonalite) was 5.4 x 10-17 m2/s. 241Am was only sorbed on the surface of the sample and thus no apparent diffusion coefficient could be calculated. Filling materials, chlorite and secondary minerals in tonalite and rapakivi granite increased diffusion into the mother rock. Radionuclides were sorbed both into the filling material and through fillers into the rock matrix. Cs and Sr penetrated though calcite filling material in mica gneiss into the mother rock. Calcite didn't influence on diffusion of radionuclides. Penetration depths of Cs and Sr were about the same for filled and unfilled samples

  19. Sorption and diffusion of cobalt, nickel, strontium, iodine, cesium and americium in natural fissure surfaces and drill core cups studied by autoradiography, 2

    International Nuclear Information System (INIS)

    Theoretical studies on geological disposal of radioactive waste in fractured crystalline rock and migration of radionuclides in groundwater circulating through the fractured zones have indicated the importance of diffusion into the rock matrix. Samples chosen for this study were filled and unfilled natural fracture surfaces and drill cores having a central drilled cavity ('drill core cups'). Samples originated from the two nuclear power plant sites in Finland: mica gneiss and tonalite from Olkiluoto and rapakivi granite from Haestholmen in Loviisa. An autoradiographic method was used for determination of the penetration depths and calculation of diffusion coefficients of Cs-134, Sr-90, Co-60, Ni-63, I-125 and Am-241. Emphasis was also directed to testing the quantitative autoradiographic method for diffusion coefficient measurements. After one year's contact time the penetration depths of strontium in tonalite were 15 mm and 10 mm for the filled and unfilled natural fracture surface samples and 5 mm for drill core cups. In the filled natural fracture surface sample of rapakivi granite the penetration depth of strontium was 35 mm. For cesium penetration depths in tonalite from 2.0 mm (unfilled natural surface) to 3.0 mm (drill core cup) were observed. For cobalt a penetration depth of 0.9 mm was found in the drill core cup sample of tonalite after contact time of one year and 1.5 mm in the filled natural fracture surface of rapakivi granite after contact time of six months. The range of Da-values of strontium was 1.4 x 10-14 - 1.1 x 10-13 m2/s. The Da-values for cesium and cobalt in tonalite (drill core cup samples) were 7 x 10-15 m2/s and 5 x 10-16 m2/s, respectively

  20. Sequential isotopic determination of plutonium, thorium, americium and uranium in the air filter and drinking water samples around the WIPP site

    International Nuclear Information System (INIS)

    The simultaneous determination of actinides in air filter and water samples around the WIPP site have been demonstrated. The analytical method is based on the selective separation and purification by anion exchange and Eichrome-TEVA, TRU and DGA-resin followed by determination of actinides by alpha spectrometry. Counting sources for alpha spectrometric measurements were prepared by microcoprecipitation on neodymium fluoride (NdF3). Radiochemical yields were determined using 242Pu, 229Th, 243Am and 232U as tracers. The validation of the method is performed through the analysis of reference materials or participating in laboratory intercomparison programs. The plutonium concentrations in aerosols varied seasonally, being highest in spring and summer due to the spring-time enhanced wind-storm transportation of radioactive aerosols from the stratosphere to the troposphere. The 238Pu/239+240Pu activity ratio in the aerosol samples is typically close to that of global fallout from historic above-ground nuclear weapons testing. The results presented here indicate that the source of plutonium in the WIPP environment results mainly from global nuclear fallout and there is no evidence of increases in radiological contaminants in the region that could be attributed to releases from the WIPP. (author)

  1. Separation of americium(III) and europium(III) from nitrate medium using a binary mixture of Cyanex-301 with neutral donor ligands

    International Nuclear Information System (INIS)

    Separation behaviour of Am3+ and Eu3+ was investigated from aqueous nitrate medium using a binary mixture of Cyanex-301 (bis(2,4,4- trimethylpentyl) dithiophosphinic acid) and several N, O or S donor ligands such as 1,10-phenanthroline (phen), TPTZ (2,4,6- tri(2-pyridyl)- 1,3,5- triazine), 2,2'-bipyridyl(bipy), hexa thia 18 crown 6 (S618C6), TBP (tri-n-butyl phosphate), TBTP (tri-n-butyl thiophosphate) in toluene. The S.F. values of >40,000 obtained with bipy and phen are the highest reported to date. (author)

  2. Bis(2-ethylhexyl)diglycolamic acid for the mutual separation of Europium (III) and Americium (III) from citric acid - nitric acid medium

    International Nuclear Information System (INIS)

    High-level liquid waste arises from fast reactor fuel reprocessing contains significant quantities of lanthanides and trivalent minor actinides. Recently, the partitioning of minor actinides from fast reactor-high active waste (FR-HAW) using a TRUEX solvent, composed of a solution of 0.2 M octyl(phenyl)-N,N-diisobutylcarbamoylmethylphosphine oxide (CMPO)-1.2 M tri-n-butylphosphate (TBP) in n-dodecane is demonstrated. A new stripping formulation composed of a solution of 0.1 M citric acid in 0.1 M nitric acid was employed for back extraction of trivalents from the loaded TRUEX solvent. Thus the mutual separation lanthanides and actinides requires a suitable extractant for separating them from citric acid medium

  3. I. Nuclear Production Reaction and Chemical Isolation Procedure for Americium-240 II. New Superheavy Element Isotopes: Plutonium-242(Calcium-48,5n)(285)114

    Science.gov (United States)

    Ellison, Paul Andrew

    2011-12-01

    Part I discusses the study of a new nuclear reaction and chemical separation procedure for the production of 240Am. Thin 242Pu, natTi, and natNi targets were coincidently activated with protons from the 88-Inch Cyclotron, producing 240Am, 48V, and 57Ni, respectively. The radioactive decay of these isotopes was monitored using high-purity Ge gamma ray detectors in the weeks following irradiation. The excitation function for the 242 Pu(p, 3n)240Am nuclear reaction was measured to be lower than theoretical predictions, but high enough to be the most viable nuclear reaction for the large-scale production of 240 Am. Details of the development of a chemical separation procedure for isolating 240Am from proton-irradiated 242Pu are discussed. The separation procedure, which includes two anion exchange columns and two extraction chromatography columns, was experimentally investi- gated using tracer-level 241Am, 239Pu, and model proton-induced fission products 95Zr, 95Nb, 125Sb, and 152Eu. The separation procedure was shown to have an Am/Pu separation factor of >2x10 7 and an Am yield of ˜70%. The separation procedure was found to purify the Am sample from >99.9% of Eu, Zr, Nb, and Sb. The procedure is well suited for the processing of ˜1 gram of proton-irradiated 242Pu to produce a neutron-induced fission target consisting of tens of nanograms of 240Am. Part II describes the use of the Berkeley Gas-filled Separator at the Lawrence Berkeley National Laboratory 88-Inch Cyclotron for the study of the 242Pu(48Ca,5n)285114 nuclear re- action. The new, neutron-deficient, superheavy element isotope 285114 was produced in 48Ca irradiations of 242Pu targets at a center-of-target beam energy of 256 MeV ( E* = 50 MeV). The alpha decay of 285114 was followed by the sequential alpha decay of four daughter nuclides, 281Cn, 277Ds, 273Hs, and 269 Sg. 265Rf was observed to decay by spontaneous fission. The measured alpha-decay Q-values were compared with those from a macroscopic-microscopic nuclear mass model to give insight into superheavy element shell effects. The 242Pu(48Ca, 5n)285114 cross section was 0.6-0.2 +1.3 pb.

  4. Simulation of loading conditions for a type A package containing Americium-241 involved in an airplane crash at Detroit Metro Airport in January 1983

    International Nuclear Information System (INIS)

    On January 11, 1983, a United Airlines DC-8F cargo aircraft crashed shortly after takeoff from Detroit Metro Airport. A lower rear cargo pit had a type A package containing 10,000 241Am solid-form sources, each of 1.5-μCi strength, used in smoke detectors. Although burned and somewhat battered, the 1-gal metal can holding all these sources was recovered completely intact with no release of radioactive material to the environment or loss of any sources. This report describes Lawrence Livermore National Laboratory's attempt to reconstruct, as closely as practical, the mechanical and thermal environments experienced by this can during and immediately after the accident. Mechanical loading of the metal can in a shipping carton was simulated by impacts from a 16-lb pendulum mass falling through vertical displacements of up to 6 ft. Internal damage ranged from imperceptible to sufficient to demolish internal plastic jars and to produce major deformation of the metal can. The thermal environment was best reproduced by the simple burning of the outer shipping carton. 6 references, 27 figures

  5. Chemical speciation of strontium, americium, and curium in high level waste: Predictive modeling of phase partitioning during tank processing. Annual progress report, October 1996--September 1997

    International Nuclear Information System (INIS)

    'The program at Florida State University was funded to collaborate with Dr. A. Felmy (PNNL) on speciation in high level wastes and with Dr. D. Rai (PNNL) on redox of Pu under high level waste conditions. The funding provided support for 3 research associates (postdoctoral researchers) under Professor G. R. Choppin as P.I. Dr. Kath Morris from U. Manchester (Great Britain), Dr. Dean Peterman and Dr. Amy Irwin (both from U. Cincinnati) joined the laboratory in the latter part of 1996. After an initial training period to become familiar with basic actinide chemistry and radiochemical techniques, they began their research. Dr. Peterman was assigned the task of measuring Th-EDTA complexation prior to measuring Pu(IV)-EDTA complexation. These studies are associated with the speciation program with Dr. Felmy. Drs. Morris and Irwin initiated research on redox of plutonium with agents present in the Hanford Tanks as a result of radiolysis or from use in separations. The preliminary results obtained thus far are described in this report. It is expected that the rate of progress will continue to increase significantly as the researchers gain more experience with plutonium chemistry.'

  6. Americium, Cesium, and Plutonium Colloid-Facilitated Transport in a Groundwater/Bentonite/Fracture Fill Material System: Column Experiments and Model Results

    Science.gov (United States)

    Dittrich, T. M.; Boukhalfa, H.; Reimus, P. W.

    2014-12-01

    The objective of this study was to investigate and quantify the effects of desorption kinetics and colloid transport on radionuclides with different sorption affinities. We focused on quantifying transport mechanisms important for upscaling in time and distance. This will help determine the long-term fate and transport of radionuclides to aid in risk assessments. We selected a fractured/weathered granodiorite at the Grimsel Test Site (GTS) in Switzerland as a model crystalline rock repository system because the system has been thoroughly studied and field experiments involving radionuclides have already been conducted. Working on this system provides a unique opportunity to compare lab experiments with field-scale observations. Weathered fracture fill material (FFM) and bentonite used as backfill at the GTS were characterized (e.g., BET, SEM/EDS, QXRD), and batch and breakthrough column experiments were conducted. Solutions were prepared in synthetic groundwaters that matched the natural water chemistry. FFM samples were crushed, rinsed, sieved (150-355 μm), and equilibrated with synthetic groundwater. Bentonite was crushed, sodium-saturated, equilibrated with synthetic groundwater, and settled to yield a stable suspension. Suspensions were equilibrated with Am, Cs, or Pu. All experiments were conducted with Teflon®materials to limit sorption to system components. After radionuclide/colloid injections reached stability, radionuclide-free solutions were injected to observe the desorption and release behavior. Aliquots of effluent were measured for pH, colloid concentration, and total and dissolved radionuclides. Unanalyzed effluent from the first column was then injected through a second column of fresh material. The process was repeated for a third column and the results of all three breakthrough curves were modeled with a multi-site/multi-rate MATLAB code to elucidate the sorption rate coefficients and binding site densities of the bentonite colloids and fracture fill material. Nearly 50% of the sorbed Am was exchanged from the colloids to the fracture filling material in each of the three columns; whereas, less Cs and Pu was desorbed with each pass through a new column. Using a two-site kinetic model allowed for interrogation of desorption rates and dominant transport parameters.

  7. Extraction and separation of uranium, plutonium and americium from MOX fuel rejected waste and analytical phosphoric acid based waste using organophosphorus extractants

    International Nuclear Information System (INIS)

    The extraction of U, Pu and Am from HNO3 solutions using tri-n-butyl phosphate (TBP), a mixture of 0.2M CMPO + 1.2M TBP and Cyanex-923 in dodecane has been carried out. The mixed oxide (MOX) fuel rejected during fabrication, termed as dirty rejected oxide (DRO) sludge was dissolved in HNO3 and a procedure has been developed to recover U, Pu and Am from this waste using the above extractants. Also, a procedure has been developed to recover almost quantitatively the U, Pu and Am content from one of the difficult analytical wastes generated after the Davies and Gray analysis of U, in presence of Pu containing H3PO4, H2SO4, and HNO3, by using a mixture of 30% Cyanex-923 + 20% TBP in dodecane. (author)

  8. Uncertainty induced by chest wall thickness assessment methods on lung activity estimation for plutonium and americium: a large population-based study

    International Nuclear Information System (INIS)

    In vivo lung counting aims at assessing the retained activity in the lungs. The calibration factor relating the measured counts to the worker’s specific retained lung activity can be obtained by several means and strongly depends on the chest wall thickness. Here we compare, for 374 male nuclear workers, the activity assessed with a reference protocol, where the material equivalent chest wall thickness is known from ultrasound measurements, with two other protocols. The counting system is an array of four germanium detectors. It is found that non site-specific equations for the assessment of the chest wall thickness induce large biases in the assessment of activity. For plutonium isotopes or 241Am the proportion of workers for whom the retained activity is within ± 10% of the reference one is smaller than 10%. The use of site-specific equations raises this proportion to 20% and 58% for plutonium and 241Am, respectively. Finally, for the studied population, when site-specific equations are used for the chest wall thickness, the standard uncertainties for the lung activity are 42% and 12.5%, for plutonium and 241Am, respectively. Due to the relatively large size of the studied population, these values are a relatively robust estimate of the uncertainties due to the assessment of the chest wall thickness for the current practice at this site. (paper)

  9. Nuclear and Physical Methods of Control For soil and Near-ground Air Contamination With Plutonium and Americium-241 in Belarus

    International Nuclear Information System (INIS)

    As a result of the Chernobyl NPP accident considerable territories of Belarus have been contaminated with Pu and 241Am. The absence of instrumental techniques for a direct analysis of transuranium elements (TUE) in the objects of the environment has made the using of laborious radiochemical methods inevitable what, in its turn, has limited a necessary scale of investigations on TUE problem. The paper presents the more cheap and express instrumental nuclear and physical techniques for Pu and 241Am analysis in soils and near-ground layer of air having been developed at the Institute of Power Engineering Problems / National Academy of Sciences of Belarus (IPEP NASB), as well as some results having been obtained using these techniques

  10. Modeling of neptunium(V), plutonium(IV) and americium(III) sorption on soils in the presence of humic acid

    International Nuclear Information System (INIS)

    Sorption experiments of 237Np(V)O2+, 238Pu(IV)4+ and 241Am(III)3+ onto soils in the presence of humic acid have been performed by a batch system, in order to clarify effects of humic acid on sorption of the radionuclides on soils. Soils used in the present experiments were a coastal sand which does not sorb humic acid, and an ando soil which sorbs humic acid very well and is known to have a high content of humic substances. The distribution coefficient of 237Np for both soils was not affected by the presence of humic acid, since 237Np much little interact with humic acid. The distribution coefficient of 241Am for both soils decreased as the humic acid concentration increased. Also the distribution coefficient of 238Pu for the coastal sand decreased with increasing humic acid concentration. On the other hand, as to the ando soil, the distribution coefficient of 238Pu in the presence of humic acid was larger than that in the absence of humic acid, in the humic acid concentration range below 5 mg/dm3, although it decreased with increasing humic acid concentration over 5 mg/dm3. These results suggest that apparent sorption behavior of 238Pu and 241Am on the soils may be dependent on the sorption ability of their humic complexes. The distribution coefficient of the three radionuclides for the soils could be evaluated by the sorption equilibrium model taking account of the effects of the sorption of both humic acid itself and humic complexes of radionuclide on the value of the distribution coefficient, besides the complexation in aqueous phase. (author)

  11. Chemical speciation of strontium, americium, and curium in high level waste: Predictive modeling of phase partitioning during tank processing. Annual progress report, October 1996--September 1997

    Energy Technology Data Exchange (ETDEWEB)

    Felmy, A.R. [Pacific Northwest National Lab., Richland, WA (US); Choppin, G. [Florida State Univ., Tallahassee, FL (US)

    1997-12-31

    'The program at Florida State University was funded to collaborate with Dr. A. Felmy (PNNL) on speciation in high level wastes and with Dr. D. Rai (PNNL) on redox of Pu under high level waste conditions. The funding provided support for 3 research associates (postdoctoral researchers) under Professor G. R. Choppin as P.I. Dr. Kath Morris from U. Manchester (Great Britain), Dr. Dean Peterman and Dr. Amy Irwin (both from U. Cincinnati) joined the laboratory in the latter part of 1996. After an initial training period to become familiar with basic actinide chemistry and radiochemical techniques, they began their research. Dr. Peterman was assigned the task of measuring Th-EDTA complexation prior to measuring Pu(IV)-EDTA complexation. These studies are associated with the speciation program with Dr. Felmy. Drs. Morris and Irwin initiated research on redox of plutonium with agents present in the Hanford Tanks as a result of radiolysis or from use in separations. The preliminary results obtained thus far are described in this report. It is expected that the rate of progress will continue to increase significantly as the researchers gain more experience with plutonium chemistry.'

  12. Chemical speciation of strontium, americium, and curium in high level waste: Predictive modeling of phase partitioning during tank processing. 1998 annual progress report

    International Nuclear Information System (INIS)

    'In this research program, Pacific Northwest National Laboratory (PNNL) and Florida State University (FSU) are investigating the speciation of Sr and Am/Cm in the presence of selected organic chelating agents (ethylenediaminetetraacetic acid (EDTA), N-(2-hydroxyethyl)ethylenediaminetriacetic acid (HEDTA), nitrilotriacetic acid (NTA), and iminodiacetic acid (IDA)) over ranges of hydroxide, carbonate, ionic strength, and competing metal ion concentrations present in high level waste tanks. The fundamental understanding of chemical speciation reactions gained from these studies is also used to propose methodologies for removal of Sr and Am/Cm from organic chelates present in high level tank waste, via competition, displacement or other reactions, without the need for the development of costly and potentially hazardous organic destruction technologies.'

  13. Americium(III) oxidation by copper(III) periodate in nitric acid solution as compared with the action of Bi(V) compounds of sodium, lithium, and potassium

    Energy Technology Data Exchange (ETDEWEB)

    Sinkov, Sergey I.; Lumetta, Gregg J. [Pacific Northwest National Laboratory, Radiochemical Processing Lab., Richland, WA (United States)

    2015-07-01

    The oxidative action of a Cu(III) periodate compound toward Am(III) in nitric acid was studied. The extent of oxidation of Am(III) to Am(VI) was investigated using a constant initial Cu(III)-to-Am(III) molar ratio of 10:1 and varying nitric acid concentrations from 0.25 to 3.5 mol/L. From 0.25 to 3 mol/L HNO3, more than 98% of the Am(III) was oxidized to Am(VI); however, at 3.5 mol/L HNO{sub 3}, the conversion to Am(VI) was only 80%. Increasing the Cu(III)-to-Am(III) molar ratio to 20:1 in 3.5 mol/L HNO{sub 3} resulted in 98% conversion to Am(VI). For comparison, oxidation of Am(III) with NaBiO{sub 3} was studied at 3.5 mol/L HNO{sub 3} and the same stoichiometric excess of Bi(V) oxidant over Am(III) (stoichiometric ratio of 3.33:1). With NaBiO{sub 3}, the extent of Am(III) conversion to Am(VI) was only 19%, while with the Cu(III) compound this value was found to be about 4 times higher under otherwise identical conditions. Similar results were obtained with other Bi(V) salts. These results show that the Cu(III) periodate compound is a superior oxidant to NaBiO{sub 3}, yielding rapid conversion to Am(VI) in a homogeneous acidic solution, and is, therefore, an excellent candidate for further development of Am separation systems.

  14. The construction of TRIGA-TRAP and direct high-precision Penning trap mass measurements on rare-earth elements and americium

    OpenAIRE

    Ketelaer, J.

    2010-01-01

    Kernmassen sind eine wichtige Größe zur Untersuchung der Kernstruktur, da sie die Summe aller Wechselwirkungen im Atomkern widerspiegeln. Es gibt viele Möglichkeiten zur präzisen Massenmessung unter denen die Penningfalle die höchste Präzision erreicht. Darüber hinaus können damit absolute Massenmessungen unter Verwendung des atomaren Massenstandards Kohlenstoff als Referenz durchgeführt werden. Im Rahmen dieser Arbeit wurde das neue Doppel-Penningfallen-Massenspektrometer TRIGA-TRAP aufgebau...

  15. Ionization cross section measurement of heavy atom L levels (Z>=72) with Americium 241 γ radiation at 59.6 keV

    International Nuclear Information System (INIS)

    The cross-sections for L X-ray production by the 59.6 keV γ radiation of 241Am have been measured for heavy elements (Z > 70). The L subshell ionization cross-sections have been calculated on the basis of these measurements

  16. Solubility and speciation results from oversaturation experiments on neptunium, plutonium and americium in a neutral electrolyte with a total carbonate similar to water from Yucca Mountain Region Well UE- 25p No. 1

    Energy Technology Data Exchange (ETDEWEB)

    Torretto, P.; Becraft, K.; Prussin, T.; Roberts, K.; Carpenter, S.; Hobart, D.; Nitsche, H. [Lawrence Berkeley Lab., CA (United States)

    1995-12-01

    Solubility and speciation are important in understanding aqueous radionuclide transport through the geosphere. They define the source term for transport retardation processes such as sorption and colloid formation. Solubility and speciation data are useful in verifying the validity of geochemical codes that are a part of predictive transport models. Solubility experiments will approach solution equilibrium from both oversaturation and undersaturation. In these experiments, we have approached the solubility equilibrium from oversaturation, Results are given for solubility and speciation experiments from oversaturation of {sup 237} NpO{sub 2}{sup +} {sup 239}Pu{sup 4+}, and {sup 241}Am{sup 3+}/Nd{sup 3+} in a neutral electrolyte containing a total carbonate concentration similar to groundwater from the Yucca Mountain region, Nevada, which is being investigated as a potential high-level nuclear waste disposal site, at 25{degrees}C and three pH values. In these experiments, the solubilitycontrolling steady-state solids were identified and the speciation and/or oxidation states present in the supernatant solutions were determined.

  17. Sorption of americium(III) and europium(III) from nitric acid solutions by a novel diglycolamide-grafted silica-based resins. Pt. 2. Sorption isotherms, column and radiolytic stability studies

    International Nuclear Information System (INIS)

    Two novel diglycolamide-grafted silica-based resins (DGSRs) were used for the sorption of trivalent actinides and lanthanides from 3 M nitric acid solutions. The sorption of Am(III) onto the resin containing one diglycolamide (DGA) moiety (DGSR-I) was less efficient than the resin containing two DGA moieties (DGSR-II) with Lagergren first order rate constants of (1.20 ± 0.03) x 10-3s-1 and (2.01 ± 0.05) x 10-3s-1, respectively. The maximum sorption of Eu(III) (used as a representative of the trivalent lanthanide/actinide ions in radioactive wastes) was 10.4 ± 1.1 mg g-1 and 13.9 ± 1.3 mg g-1 by the DGSR-I and DGSR-II, respectively. The sorption of Eu(III) on the grafted silica resins followed the Langmuir monolayer sorption phenomenon with sorption energies of 16.5 ± 2.05 and 17.8 ± 1.6 kJ mol-1 for DGSR-I and DGSR-II, respectively. Column experiments revealed that the breakthrough capacity of Eu(III) on the DGSR-II column was higher than that on the DGSR-I column. Efficient elution could be achieved with a 0.01 M EDTA solution. The radiolytic stability of the resins was ascertained by exposing the resins to a gamma ray dose up to 1030 kGy resulting in a decrease of the Kd values with about 50%; at doses d values remained unaffected.

  18. Sorption of americium(III) and europium(III) from nitric acid solutions by a novel diglycolamide-grafted silica-based resins. Pt. 2. Sorption isotherms, column and radiolytic stability studies

    Energy Technology Data Exchange (ETDEWEB)

    Ansari, Seraj A.; Mohapatra, Prasanta K. [Bahabha Atomic Research Centre, Trombay, Mumbai (India). Radiochemistry Div.; Iqbal, Mudassir; Huskens, Jurriaan; Verboom, Willem [Twente Univ. (Netherlands). Lab. of Molecular Nanofabrication

    2014-07-01

    Two novel diglycolamide-grafted silica-based resins (DGSRs) were used for the sorption of trivalent actinides and lanthanides from 3 M nitric acid solutions. The sorption of Am(III) onto the resin containing one diglycolamide (DGA) moiety (DGSR-I) was less efficient than the resin containing two DGA moieties (DGSR-II) with Lagergren first order rate constants of (1.20 ± 0.03) x 10{sup -3}s{sup -1} and (2.01 ± 0.05) x 10{sup -3}s{sup -1}, respectively. The maximum sorption of Eu(III) (used as a representative of the trivalent lanthanide/actinide ions in radioactive wastes) was 10.4 ± 1.1 mg g{sup -1} and 13.9 ± 1.3 mg g{sup -1} by the DGSR-I and DGSR-II, respectively. The sorption of Eu(III) on the grafted silica resins followed the Langmuir monolayer sorption phenomenon with sorption energies of 16.5 ± 2.05 and 17.8 ± 1.6 kJ mol{sup -1} for DGSR-I and DGSR-II, respectively. Column experiments revealed that the breakthrough capacity of Eu(III) on the DGSR-II column was higher than that on the DGSR-I column. Efficient elution could be achieved with a 0.01 M EDTA solution. The radiolytic stability of the resins was ascertained by exposing the resins to a gamma ray dose up to 1030 kGy resulting in a decrease of the K{sub d} values with about 50%; at doses <500 kGy the K{sub d} values remained unaffected.

  19. Interaction and transport of actinides in natural clay rock with consideration of humic substances and clay organics. Characterization and quantification of the influence of clay organics on the interaction and diffusion of uranium and americium in the clay. Joint project

    Energy Technology Data Exchange (ETDEWEB)

    Bernhard, Gert [Helmholtz-Zentrum Dresden-Rossendorf e.V. (Germany). Inst. of Radiochemistry; Schmeide, Katja; Joseph, Claudia; Sachs, Susanne; Steudtner, Robin; Raditzky, Bianca; Guenther, Alix

    2011-07-01

    The objective of this project was the study of basic interaction processes in the systems actinide - clay organics - aquifer and actinide - natural clay - clay organics - aquifer. Thus, complexation, redox, sorption and diffusion studies were performed. To evaluate the influence of nitrogen, phosphorus and sulfur containing functional groups of humic acid (HA) on the complexation of actinides in comparison to carboxylic groups, the Am(III) and U(VI) complexation by model ligands was studied by UV-Vis spectroscopy and TRLFS. The results show that Am(III) is mainly coordinated via carboxylic groups, however, probably stabilized by nitrogen groups. The U(VI) complexation is dominated by carboxylic groups, whereas nitrogen and sulfur containing groups play a minor role. Phosphorus containing groups may contribute to the U(VI) complexation by HA, however, due to their low concentration in HA they play only a subordinate role compared to carboxylic groups. Applying synthetic HA with varying sulfur contents (0 to 6.9 wt.%), the role of sulfur functionalities of HA for the U(VI) complexation and Np(V) reduction was studied. The results have shown that sulfur functionalities can be involved in U(VI) humate complexation and act as redox-active sites in HA for the Np(V) reduction. However, due to the low content of sulfur in natural HA, its influence is less pronounced. In the presence of carbonate, the U(VI) complexation by HA was studied in the alkaline pH range by means of cryo-TRLFS (-120 C) and ATR FT-IR spectroscopy. The formation of the ternary UO{sub 2}(CO{sub 3}){sub 2}HA(II){sup 4-} complex was detected. The complex formation constant was determined with log {beta}{sub 0.1} M = 24.57 {+-} 0.17. For aqueous U(VI) citrate and oxalate species, luminescence emission properties were determined by cryo-TRLFS and used to determine stability constants. The existing data base could be validated. The U(VI) complexation by lactate, studied in the temperature range 7 to 65 C, was found to be endothermic and entropy-driven. In contrast, the complex stability constants determined for U(VI) humate complexation at 20 and 40 C are comparable, however, decrease at 60 C. For aqueous U(IV) citrate, succinate, mandelate and glycolate species stability constants were determined. These ligands, especially citrate, increase solubility and mobility of U(IV) in solution due to complexation. The U(VI) sorption onto crushed Opalinus Clay (OPA, Mont Terri, Switzerland) was studied in the absence and presence of HA or low molecular weight organic acids, in dependence on temperature and CO2 presence using OPA pore water as background electrolyte. Distribution coefficients (K{sub d}) were determined for the sorption of U(VI) and HA onto OPA with (0.0222 {+-} 0.0004) m{sup 3}/kg and (0.129 {+-} 0.006) m{sup 3}/kg, respectively. The U(VI) sorption is not influenced by HA ({<=}50 mg/L), however, decreased by low molecular weight organic acids ({>=} 1 x 10{sup -5} M), especially by citrate and tartrate. With increasing temperature, the U(VI) sorption increases both in the absence and in the presence of clay organics. The U(VI) diffusion in compacted OPA is not influenced by HA at 25 and 60 C. Predictions of the U(VI) diffusion show that an increase of the temperature to 60 C does not accelerate the migration of U(VI). With regard to uranium-containing waste, it is concluded that OPA is suitable as host rock for a future nuclear waste repository since OPA has a good retardation potential for U(VI). (orig.)

  20. Monitored Natural Attenuation of Inorganic Contaminants in Ground Water Volume 3 Assessment for Radionuclides IncludingTritium, Radon, Strontium, Technetium, Uranium, Iodine, Radium, Thorium, Cesium, and Plutonium-Americium

    Science.gov (United States)

    The current document represents the third volume of a set of three volumes that address the technical basis and requirements for assessing the potential applicability of MNA as part of a ground-water remedy for plumes with nonradionuclide and/or radionuclide inorganic contamina...

  1. Study of plutonium and americium contamination in agricultural area, radiological impact caused by consumption of vegetables of this area; Estudio de la contaminacion de plutonio y americio en un area agricola, impacto radiologico ocasionado por consumo de vegetales contaminados

    Energy Technology Data Exchange (ETDEWEB)

    Espinosa, Assuncion; Aragon, Antonio; Cruz, Berta de la; Gutierrez, Jose [Centro de Investigaciones Energeticas Medioambientales y Tecnologicas, Madrid (Spain). Dept. de Impacto Ambiental de la Energia

    2001-07-01

    The transuranide concentration has been studied for 30 years in vegetable production, crops in wide extensions and in private-owned farms, all of them situated within the Pu-contaminated area of Palomares due to an air accident in 1966. Based on these studies, a preliminary estimation of the radiological risk caused by the consumption of these products by the inhabitants was possible. The results show that most of the fruits present a surface contamination, which disappears or is significantly reduced when they are washed. The contamination present in edible parts of the vegetables, as well as the contamination of other products included in the diet, has facilitated the estimation of the effective dose for ingestion and the committed effective dose for 50 years for the inhabitants. The main conclusions are: those plants, whose cultivation period is less than a year, present a low level of contamination; the green parts of the plants have a higher contamination than the fruits; the Pu soil to plant transfer factor is very low. In general, those plants that have remained in the contaminated land for several years present a high contamination level; the ingestion of products from Palomares does not represent an important risk for the population, even in the case that the products were totally consumed by a critical group.( author)

  2. Uptake of actinides by sulphonated phosphinic acid resin from acid medium

    International Nuclear Information System (INIS)

    The removal of uranium and americium from nitric acid solutions by sulphonated phosphinic acid resin has been investigated. The capacity of the sulphonated resin exceeds the capacities of phosphinic acid resin and commercial cation exchange resin. Other advantages of the sulphonated resin for uranium and americium removal include reduced sensitivity to acidity and inert salt concentration. (author)

  3. Process for cleaning a nitric acid U/Pu-solution

    International Nuclear Information System (INIS)

    The impure starting solution is passed through a cation exchange column following oxidation of the U/Pu ions present to the hexavalent state. Here the impurities, in particular Americium, are retained and after subsequent elution are handled by known waste treatments or waste utilization (Americium). (orig.)

  4. Calculated Atomic Volumes of the Actinide Metals

    DEFF Research Database (Denmark)

    Skriver, H.; Andersen, O. K.; Johansson, B.

    1979-01-01

    The equilibrium atomic volume is calculated for the actinide metals. It is possible to account for the localization of the 5f electrons taking place in americium.......The equilibrium atomic volume is calculated for the actinide metals. It is possible to account for the localization of the 5f electrons taking place in americium....

  5. Chemistry research and development progress report, May-October, 1978

    International Nuclear Information System (INIS)

    Work in progress includes: calorimetry and thermodynamics of nuclear materials; americium recovery and purification; optimization of the cation exchange process for recovering americium and plutonium from molten salt extraction residues, photochemical separations of actinides; advanced ion exchange materials and techniques; secondary actinide recovery; removal of plutonium from lathe coolant oil; evaluation of tributyl phosphate-impregnated sorbent for plutonium-uranium separations; plutonium recovery in advance size reduction facility; plutonium peroxide precipitation; decontamination of Rocky Flats soil; soil decontamination at other Department of Energy sites; recovery of actinides from combustible wastes; induction-heated, tilt-pour furnace; vacuum melting; determination of plutonium and americium in salts and alloys by calorimetry; plutonium peroxide precipitation process; silica removal study; a comparative study of annular and Raschig ring-filled tanks; recovery of plutonium and americium from a salt cleanup alloy; and process development for recovery of americium from vacuum melt furnace crucibles

  6. Chemistry research and development progress report, May-October, 1978

    Energy Technology Data Exchange (ETDEWEB)

    Miner, F. J.

    1979-08-30

    Work in progress includes: calorimetry and thermodynamics of nuclear materials; americium recovery and purification; optimization of the cation exchange process for recovering americium and plutonium from molten salt extraction residues, photochemical separations of actinides; advanced ion exchange materials and techniques; secondary actinide recovery; removal of plutonium from lathe coolant oil; evaluation of tributyl phosphate-impregnated sorbent for plutonium-uranium separations; plutonium recovery in advance size reduction facility; plutonium peroxide precipitation; decontamination of Rocky Flats soil; soil decontamination at other Department of Energy sites; recovery of actinides from combustible wastes; induction-heated, tilt-pour furnace; vacuum melting; determination of plutonium and americium in salts and alloys by calorimetry; plutonium peroxide precipitation process; silica removal study; a comparative study of annular and Raschig ring-filled tanks; recovery of plutonium and americium from a salt cleanup alloy; and process development for recovery of americium from vacuum melt furnace crucibles.

  7. Effect of industrial pollution on the distribution of Pu and Am in soil and on soil-to-plant transfer of Pu and Am in a pine forest in SW Finland

    International Nuclear Information System (INIS)

    The effect of industrial pollution on the behavior of plutonium and americium was evaluated in a pine forest in the vicinity of a Cu-Ni smelter in SW Finland. Soil and vegetation were sampled at distances of 0.5, 2, 4 and 8 km from the smelter. The vertical distribution of plutonium and americium was studied in litter, organic layer and mineral layers. The amount of Pu and Am in the litter layer increased and that in the organic layer decreased towards the smelter. Concentrations of plutonium and americium in different vegetation species decreased in the order mushrooms > lichens (Cladina spp., Cetraria islandica) > Empetrum nigrum > Vaccinium vitis-idaea. (author)

  8. The behaviour of Eu, Pu, Am radionuclide at burning radioactive graphite in an oxygen atmosphere. Computer experiments

    Directory of Open Access Journals (Sweden)

    Kolbin T.S.

    2015-01-01

    Full Text Available Be means of the method of computer thermodynamic simulation we studied the behaviour of the europium, plutonium and americium from the combustion of radioactive graphite in oxygen. Europe is in the form of condensed EuOCl, Eu2O3 and vapour EuO. Pluto is in the form of condensed vapour PuO2 and PuO2. Americium is a condensed AmO2, Am2O3 and vapour Am. The basic reactions occurring compounds with europium, plutonium and americium. Equilibrium constants of the reactions have been determined.

  9. Alpha self-irradiation effects in ternary oxides of actinides elements: The zircon-like phases AmIIIVO4 and AIINpIV(VO4)2 (A=Sr, Pb)

    International Nuclear Information System (INIS)

    We report the experimental studies of irradiation damage from alpha decay in neptunium and americium vanadates versus cumulative dose. The isotopes used were the transuranium α-emitter 237Np and the α,γ-emitter 241Am. Neptunium and americium vanadates self-irradiation was studied by X-ray diffraction method (XRD). The comparison of the powder diffraction patterns reveal that the irradiation has no apparent effect on the neptunium phases while the americium vanadate swells and becomes metamict as a function of cumulative dose

  10. Methodology for the Inventory and Assessment of Americium Contamination Level in 1987 in an Area of Palomares Contaminated with Plutonium Weapon Grade; Estimacion del Contenido de Americio Existente en el Ano 1987 en una Zona de Palomares Contaminada en 1966 por Material de Plutonio Grado Bomba

    Energy Technology Data Exchange (ETDEWEB)

    Espinosa, A.; Aragon, A.; Cruz de la, B.

    2001-07-01

    This paper presents a methodology applied for the assessment of the ''241 Am coming from the decay of ''241 Pu isotope content in a contaminated area of Palomares, where the clean-up work done in 1966, given the negligible agricultural importance of such area at the time and its geographical characteristics, was not of the same magnitude as for the rest of the region. (Author) 4 refs.

  11. Electroprecipitation of potassium americyl carbonate from potassium carbonate solutions

    International Nuclear Information System (INIS)

    Precipitation of potassium americyl carbonate was carried out at multigram scale by oxidizing americium(III) at the platinum anode in 3M K2CO3 solutions. Early investigations were conducted on pure americium 241 solutions on the 10 to 40 mg scale, in order to study the different parameters of the electrolysis, and to prove the feasibility of the process. Further experiments were performed on the 20 g scale, in impure americium 241 solutions. Electrolysis performed at 600C with a platinum grid as the anode, and a tantalum rod immersed in a cathodic compartment, precipitated 20 g of americium 241 with yields above 99% in 2 h. The electroprecipitation process presents the advantage of being clean and suitable for automation techniques in comparison with the chemical oxidation process using potassium persulphate. (orig.)

  12. Literatuuronderzoek plutoniumanalyses

    NARCIS (Netherlands)

    Glastra P; Kwakman PJM; LSO

    1997-01-01

    Dit rapport beschrijft de laatste ontwikkelingen in de radiochemische bepaling van plutonium in monstermatrices zoals luchtstoffilters, regenwater, gras en bodem. De radiochemische scheiding van plutonium van storende alfastralers, zoals americium en curium, is door de recente ontwikkeling van spec

  13. The TRUSPEAK Concept: Combining CMPO and HDEHP for Separating Trivalent Lanthanides from the Transuranic Elements

    Energy Technology Data Exchange (ETDEWEB)

    Lumetta, Gregg J.; Gelis, Artem V.; Braley, Jenifer C.; Carter, Jennifer C.; Pittman, Jonathan W.; Warner, Marvin G.; Vandegrift, George F.

    2013-04-08

    Combining octyl(phenyl)-N,N-diisobutyl-carbamoylmethyl-phosphine oxide (CMPO) and bis-(2-ethylhexyl) phosphoric acid (HDEHP) into a single process solvent for separating transuranic elements from liquid high-level waste is explored. Co-extraction of americium and the lanthanide elements from nitric acid solution is possible with a solvent mixture consisting of 0.1-M CMPO plus 1-M HDEHP in n-dodecane. Switching the aqueous-phase chemistry to a citrate-buffered solution of diethylene triamine pentaacetic acid (DTPA) allows for selective stripping of americium, separating it from the lanthanide elements. Potential strategies for managing molybdenum and zirconium (both of which co-extract with americium and the lanthanides) have been developed. The work presented here demonstrates the feasibility of combining CMPO and HDEHP into a single extraction solvent for recovering americium from high-level waste and its separation from the lanthanides.

  14. Integrated study of the behavior of transuranic elements in the marine environment

    International Nuclear Information System (INIS)

    In order to construct a model of radionuclide kinetics in an aquatic ecosystem, americium ions were chosen for study. Results will be applied to thorium, plutonium, neptunium and uranium for comparison of environmental behavior

  15. Rubbia proposes a speedier voyage to Mars and back

    CERN Multimedia

    Abbott, A

    1999-01-01

    Carlo Rubbia has designed a propulsion engine that uses fission fragments of americium to directly heat a propulsion gas. He estimates it would allow a manned trip to Mars and back in around a year (8 paragraphs).

  16. Medical grade 238Pu from 241Am: progress report

    International Nuclear Information System (INIS)

    Shielding requirements for fabrication of americium targets were evaluated, a preliminary flowsheet for processing the irradiated Am targets was developed, and the AMRAD computer program, which models the irradiation cycle, was improved

  17. An investigation into radiological health and safety at the Ministry of Defence (Procurement Executive) Atomic Weapons Research Establishment, Aldermaston

    International Nuclear Information System (INIS)

    The report is in sections, as follows: introduction; radiation exposure (sources of radiation exposure, monitoring methods, protection criteria, plutonium, uranium, americium, tritium, external exposure, environmental releases, general); problems of staffing; buildings; conclusions. (U.K.)

  18. Actinide recovery from pyrochemical residues

    International Nuclear Information System (INIS)

    We demonstrated a new process for recovering plutonium and americium from pyrochemical waste. The method is based on chloride solution anion exchange at low acidity, or acidity that eliminates corrosive HCl fumes. Developmental experiments of the process flow chart concentrated on molten salt extraction (MSE) residues and gave >95% plutonium and >90% americium recovery. The recovered plutonium contained 62- from high-chloride low-acid solution. Americium and other metals are washed from the ion exchange column with lN HNO3-4.8M NaCl. After elution, plutonium is recovered by hydroxide precipitation, and americium is recovered by NaHCO3 precipitation. All filtrates from the process can be discardable as low-level contaminated waste. Production-scale experiments are in progress for MSE residues. Flow charts for actinide recovery from electro-refining and direct oxide reduction residues are presented and discussed

  19. Chemistry research and development. Progress report, November 1978-April 1979

    International Nuclear Information System (INIS)

    The status of the following studies is given: calorimetry and thermodynamics of nuclear materials; americium recovery and purification; optimization of the cation exchange process for recovering americium and plutonium from molten net extraction residues; evaluation and comparison of bidentate extractants and methods for actinide recovery; a combined anion exchange-bidontate organophosphorus extraction process for molten salt extraction residues; a combined anion exchange-extraction chromatography technique for secondary recovery; plutonium recovery in the Advanced Size Reduction Facility; decontamination of Rocky Flats soil; separating lead and calcium from americium by chromate and oxalate precipitation; demonstration of the pyroredox process in the induction-heated, tilt-pour furnace; process development for recovery of americium from vacuum melt furnace crucibles; plutonium peroxide precipitation process; and a comparative study of annular and Raschig ring-filled tanks

  20. Miniature DIAMEX processes in a hollow fibre module micro-plant: process development and optimisation

    International Nuclear Information System (INIS)

    A hollow fibre module (HFM) micro-plant was built to perform continuous liquid-liquid extraction tests with very small feed volumes, using miniature HFM as phase contactors. Spiked DIAMEX tests (i.e., co-extraction of americium, curium, and lanthanides from PUREX raffinate) were performed in this plant. Following some flow sheet modifications, raffinate decontamination factors of up to 30 000 and 900 were achieved for americium and curium, respectively. (orig.)

  1. Ascophyllum nodosum (L.) Le Jolis as a bioindicator of radioactivity in the Irish Sea

    OpenAIRE

    Bourne, G S; Assinder, D J

    1991-01-01

    The response of Ascophyllum nodosum to a sudden increase in radioactivity analogous to a nuclear incident is examined in the field. super(137)Cs, super(241)Am and super(239+240)Pu showed net accumulation with exposure time, unlike natural super(228)Th, which was used as a control. Caesium had the highest accumulation rate followed by americium and finally plutonium. Younger plant sections were found to accumulate all the radionuclides significantly faster than older plant sections. Americium ...

  2. Hybrid chemical and nondestructive-analysis technique

    Energy Technology Data Exchange (ETDEWEB)

    Hsue, S.T.; Marsh, S.F.; Marks, T.

    1982-01-01

    A hybrid chemical/NDA technique has been applied at the Los Alamos National Laboratory to the assay of plutonium in ion-exchange effluents. Typical effluent solutions contain low concentrations of plutonium and high concentrations of americium. A simple trioctylphosphine oxide (TOPO) separation can remove 99.9% of the americium. The organic phase that contains the separated plutonium can be accurately assayed by monitoring the uranium L x-ray intensities.

  3. Sorption studies of radioelements on geological materials

    OpenAIRE

    Berry, J. A; 油井 三和; 北村 暁

    2007-01-01

    Batch sorption experiments have been carried out to study the sorption of uranium, technetium, curium, neptunium, actinium, protactinium, polonium, americium and plutonium onto bentonite, granodiorite and tuff. Mathematical modelling using the HARPHRQ program and the HATCHES database was carried out to predict the speciation of uranium and technetium in the equilibrated seawater, and neptunium, americium and plutonium in the rock equilibrated water. Review of the literature for thermodynamic ...

  4. Dynamic tests for actinide/lanthanide separation by CMPO solvent in fluorinated diluents

    Energy Technology Data Exchange (ETDEWEB)

    Tkachenko, L.; Babain, V.; Alyapyshev, M.; Vizniy, A.; Il' in, A. [V. G. Khlopin Radium Institute, 2nd Murinskiy Ave 28., St. Petersburg 194021 (Russian Federation); Shadrin, A. [A.A. Bochvar High-technology Research Institute of Inorganic Materials, 5-a, Rogova str., Moscow 123098 (Russian Federation)

    2013-07-01

    Actinide and lanthanide extraction by new solvent: 0.2 M phenyl-octyl-N,N-diiso-butylcarbamoyl-phosphine oxide (CMPO) + 30% TBP + formal of octafluoro-pentanol was studied. A dynamic test with this solvent was performed. It was shown that americium and lanthanides are effectively extracted from PUREX process raffinate. The separation of americium from light lanthanides was confirmed in the modified SETFICS flowsheet with this new solvent. (authors)

  5. Inhaled transuranics in rodents

    International Nuclear Information System (INIS)

    The purpose of this project is to examine, in small animals, the fate and effects of inhaled transuranic compounds including plutonium dioxide, americium oxides, americium nitrates and curium oxides. This project should provide data for hazard evaluation and establishment of permissible exposure limits to man for inhaled transuranics, particularly with respect to the effects of radiation dose and dose distribution. Inhalation carcinogenesis was the primary effect evaluated

  6. Hybrid chemical and nondestructive analysis technique

    International Nuclear Information System (INIS)

    A hybrid chemical/NDA technique has been applied at the Los Alamos National Laboratory to the assay of plutonium in ion-exchange effluents. Typical effluent solutions contain low concentrations of plutonium and high concentrations of americium. A simple trioctylphosphine oxide (TOPO) separation can remove 99.9% of the americium. The organic phase that contains the separated plutonium can be accurately assayed by monitoring the uranium L x-ray intensities

  7. Concentrations of 239,240Pu and 241Am of marine products in coastal waters of Ibaraki

    International Nuclear Information System (INIS)

    More than 200 samples of marine products have been collected and analyzed for plutonium and almost 100 samples for americium around Hitachi, Tokai and Oarai in the pacific coast of Ibaraki prefecture. The data have shown that the concentration factor (CF) values for plutonium were 330 for bivalve, 770 for abalone (muscle) and 610 for brown algae. For americium, the CF was calculated as 2400 for bivalve, 1000 for abalone (muscle) and 420 for brown algae. (author)

  8. Technetium(VII) extraction with calix[4]arene tetraketones and tetraesters from acid and alkaline media

    International Nuclear Information System (INIS)

    Extraction of technetium(VII) and americium(III) by tetrasubstituted by lower edge calix[4]arenes containing carbonyl and ester groups in the cone conformation was studied for choosing extractants for fractionation of liquid radioactive waste produced as a results of nuclear fuel reprocessing. It was established that both types of extractants are selective and highly effective agents for technetium(VII) extraction both from acid and alkaline solutions. Under the conditions studied no extraction of americium(III) takes place

  9. Dynamic tests for actinide/lanthanide separation by CMPO solvent in fluorinated diluents

    International Nuclear Information System (INIS)

    Actinide and lanthanide extraction by new solvent: 0.2 M phenyl-octyl-N,N-diiso-butylcarbamoyl-phosphine oxide (CMPO) + 30% TBP + formal of octafluoro-pentanol was studied. A dynamic test with this solvent was performed. It was shown that americium and lanthanides are effectively extracted from PUREX process raffinate. The separation of americium from light lanthanides was confirmed in the modified SETFICS flowsheet with this new solvent. (authors)

  10. AM(VI) PARTITIONING STUDIES: FY14 FINAL REPORT

    Energy Technology Data Exchange (ETDEWEB)

    Bruce J Mincher

    2014-10-01

    The use of higher oxidation states of americium in partitioning from the lanthanides is under continued investigation by the sigma team. This is based on the hypothesis that Am(VI) can be produced and remain stable in irradiated first cycle raffinate solution long enough to perform solvent extraction for separations. The stability of Am(VI) to autoreduction was measured using millimolar americium concentrations in a 1-cm cell with a Cary 6000 UV/Vis spectrophotometer for data acquisition. At millimolar americium concentrations, Am(VI) is stable enough against its own autoreduction for separations purposes. A second major accomplishment during FY14 was the hot test. Americium oxidation and extraction was performed using a centrifugal contactor-based test bed consisting of an extraction stage and two stripping stages. Sixty-three percent americium extraction was obtained in one extraction stage, in agreement with batch contacts. Promising electrochemical oxidation results have also been obtained, using terpyridine ligand derivatized electrodes for binding of Am(III). Approximately 50 % of the Am(III) was oxidized to Am(V) over the course of 1 hour. It is believed that this is the first demonstration of the electrolytic oxidation of americium in a non-complexing solution. Finally, an initial investigation of Am(VI) extraction using diethylhexylbutyramide (DEHBA) was performed.

  11. Distribution of 239Pu and 241Am in the human skeleton

    International Nuclear Information System (INIS)

    The 241Am and 239Pu distribution in the skeletons of two former nuclear workers has been measured. The skeletons of both individuals appear to be within normal limits for Caucasian men about 50 y old. Both had lower limb bones that were heavier than the age controls and Case I had upper-body bones that were lighter than the age control group. The distribution of americium in the skeleton of Case I, 25 years post exposure, indicated that a more rapid turnover of initially deposited americium on the bone surfaces of cancellous bone, as compared to that deposited on the bone surfaces of compact bone, had occurred. This resulted in a larger proportion of americium located in the compact bone of the extremities and a lesser quantity in the more cancellous bones of the vertebral column, pelvis and rib cage. A similar shift in the distribution of plutonium occurred in Case II in the 35 y since initial deposition, but at a slower rate than that for americium. The ratio of each actinide in the liver to that in the systemic system (liver content/systemic system content) was 0.065 and 0.436, for americium and plutonium, respectively, suggesting that a much more rapid turnover of americium in the liver, compared to plutonium, provided a much larger fraction of that nuclide for circulatory feedback to the remodeling skeletal system. 8 references, 3 tables

  12. Radiation protection - radionuclides - Synthesis sheets: Thorium-232 (ED 4317), Gallium-67 (ED 4314), Indium-111 (ED 4315), Chromium-51 (ED 4313), Thallium-201 (ED 4312), Phosphorus-33 (ED 4316), Fluorine- 18 (ED 4311), Yttrium-90 (ED 4310), Americium-241 (ED 4308), Strontium-90 (ED 4309), Sulfur-35 (ED 4307), Iodine-125 (ED 4306), Phosphorus-32 (ED 4305), Iodine-123 (ED 4304), Tritium (ED 4303), Carbon-14 (ED 4302), Technetium-99m (ED 4301), Iodine-131 (ED 4300)

    International Nuclear Information System (INIS)

    For each radionuclide, this document presents its characteristics (origin, radio-physical properties, biological properties), gives an overview of its uses, indicates and discusses its dosimetric parameters (for internal or external exposure), indicates radiation detection and contamination measurement techniques, gives an overview of means of protection (for premises, against external or internal exposure), describes the delimitation and control of premises, describes aspects related to personnel classification, training and medical monitoring, comments the issue of effluents and wastes, indicates administrative procedures related to the authorization and declaration of possession and use of sealed and unsealed sources, addresses the issue of transport, and describes what is to be done in case of incident or accident

  13. Porous metal oxide microspheres from ion exchange resin

    Science.gov (United States)

    Picart, S.; Parant, P.; Caisso, M.; Remy, E.; Mokhtari, H.; Jobelin, I.; Bayle, J. P.; Martin, C. L.; Blanchart, P.; Ayral, A.; Delahaye, T.

    2015-07-01

    This study is devoted to the synthesis and the characterization of porous metal oxide microsphere from metal loaded ion exchange resin. Their application concerns the fabrication of uranium-americium oxide pellets using the powder-free process called Calcined Resin Microsphere Pelletization (CRMP). Those mixed oxide ceramics are one of the materials envisaged for americium transmutation in sodium fast neutron reactors. The advantage of such microsphere precursor compared to classical oxide powder is the diminution of the risk of fine dissemination which can be critical for the handling of highly radioactive powders such as americium based oxides and the improvement of flowability for the filling of compaction chamber. Those millimetric oxide microspheres incorporating uranium and americium were synthesized and characterizations showed a very porous microstructure very brittle in nature which occurred to be adapted to shaping by compaction. Studies allowed to determine an optimal heat treatment with calcination temperature comprised between 700-800 °C and temperature rate lower than 2 °C/min. Oxide Precursors were die-pressed into pellets and then sintered under air to form regular ceramic pellets of 95% of theoretical density (TD) and of homogeneous microstructure. This study validated thus the scientific feasibility of the CRMP process to prepare bearing americium target in a powder free manner.

  14. Porous metal oxide microspheres from ion exchange resin

    International Nuclear Information System (INIS)

    This study is devoted to the synthesis and the characterization of porous metal oxide microsphere from metal loaded ion exchange resin. Their application concerns the fabrication of uranium-americium oxide pellets using the powder-free process called Calcined Resin Microsphere Pelletizing (CRMP). Those mixed oxide ceramics are one of the materials envisaged for americium transmutation in sodium fast neutron reactors. The advantage of such microsphere precursor compared to classical oxide powder is the diminution of the risk of fine dissemination which can be critical for the handling of highly radioactive powders such as americium based oxides and the improvement of the ability to flow for the filling of the compaction chamber. Those millimetric oxide microspheres incorporating uranium and americium were synthesized and characterizations showed a very porous microstructure very brittle in nature which occurred to be adapted to shaping by compaction. Studies allowed to determine an optimal heat treatment with calcination temperature comprised between 700-800 Celsius degrees and temperature rate lower than 2 Celsius degrees/min. Oxide Precursors were die-pressed into pellets and then sintered under air to form regular ceramic pellets of 95% of theoretical density and of homogeneous microstructure. This study validated thus the scientific feasibility of the CRMP process to prepare bearing americium target in a powder free manner. (authors)

  15. On the transmutation of Am in a fast lead-cooled system

    Indian Academy of Sciences (India)

    B P Kochurov; V N Konev; A Yu Kwaretzkheli

    2007-02-01

    Characteristics of the equilibrium fuel cycle for the core or a blanket of ADS having the structure of the core of a fast lead-cooled reactor of type BREST (Russian abbreviation for `Bystryy Reaktor so Svintsovym Teplonositelem') in a mode of americium transmutation are calculated. Americium loading was taken 5% of heavy atoms. Keeping the average multiplication factor the same as in a standard equilibrium cycle, reactivity swing over 1 year's microcycle is about 1%, that demands partial fuel reloading with a periodicity of about one month. For one year of operation, 61 kg of americium is destroyed, and due to increased 238Pu content, americium is mainly converted to fission products. Thus in a system of 1 GWt (thermal), 87 kg of americium can be transmuted yearly. The estimate of the reactivity void effect has shown that it increases to 0.6% almost linearly with the void fraction increasing up to 25% and reaches its maximum of 0.7% at a void fraction of about 50%. Application of similar strategy for ADS with a sub-criticality level ≈ 0.96–0.98 can essentially relax safety problems related to positive void effects.

  16. Development of reduction technology for oxide fuels. Lithium reduction of a simulated spent oxide fuel

    International Nuclear Information System (INIS)

    The mixed oxide pellet was reduced with lithium metal in molten lithium chloride at 923 K. The pellet was a sintered product meant to simulate spent oxide fuel containing twelve elements, which are uranium, plutonium, americium, neptunium, curium, cerium, neodymium, samarium, barium, zirconium, molybdenum, and palladium. The pellet remained intact during the reaction and most of lithium oxide, which is the by-product, dissolved in the molten salt. More than 95% of the uranium and plutonium were reduced to metal, while rare-earth elements formed an oxide solid solution in the pellet. Several percent of the initial amount of plutonium and americium was exuded from the pellet and precipitated on the bottom of the crucible. That is different from the result of the previous reduction test using a MOX (uranium-plutonium-americium ternary) pellet in which approximately 80% of the americium was exuded. The exudation of americium is considered to be suppressed by the formation of solid solution with rare-earth oxides. 10 to 30% of rare earth elements were exuded and dissolved in the molten salt. The concentrations of cerium and neodymium in the salt were consistent with the values which were calculated thermodynamically using their solubilities in lithium chloride-lithium oxide mixed molten salt. Most of the barium dissolved in the molten salt as a chloride; on the other hand, palladium remained in the pellet to form an alloy with plutonium. (author)

  17. Application of insoluble tannin adsorbent to alpha aqueous waste treatment in NUCEF

    International Nuclear Information System (INIS)

    The use of insoluble tannin adsorbent has been investigated as a means to reduce the volume of aqueous waste contaminated with americium. This work is aimed at reducing the volume of TRU waste generated within NUCEF where experiments related to back end of the nuclear fuel cycle are performed. Insoluble tannin adsorbent is a gelled material consisting of C, H and O which can be easily incinerated. The distribution coefficient and adsorption capacity of americium in insoluble tannin have been investigated and found to be 1000 ml/g in 0.02 M HNO3 and 0.013 mmol/g-dried tannin, respectively. The prospect of applying the adsorbent to the treatment of aqueous waste contaminated with americium appears promising. (author)

  18. Thermo-chemical modelling of uranium-free nitride fuels

    International Nuclear Information System (INIS)

    A production process for americium-bearing, uranium-free nitride fuels was modelled using the newly developed ALCHYMY thermochemical database. The results suggested that the practical difficulties with yield and purity are of a kinetic rather than a thermodynamical nature. We predict that the immediate product of the typical decarburisation step is not methane, but hydrogen cyanide. HCN may then undergo further reactions upon cooling, explaining the difficulty in observing any carbophoric molecules in the gaseous off stream. The thermal stability of nitride fuels in different environments was also estimated. We show that sintering of nitride compounds containing americium should be performed under nitrogen atmosphere in order to the avoid the excessive losses of americium reported from sintering under inert gas. Addition of nitrogen in small amounts to fuel pin filling gas also appears to significantly improve the in-pile stability of transuranium nitride fuels. (author)

  19. Oxidation of microquantities of transplutonium elements to tetravalent state in mineral acid solutions and their stability

    International Nuclear Information System (INIS)

    Kinetics of americium(3) microquantity oxidation and stability of forming americium(4), as well as possibility of curium and californium oxidation to tetravalent state in solutions of sulfuric and nitric acids depending on the concentration of mineral acid, potassium tungstophosphate and ammonium persulfate are studied by the extraction method. It is shown that curium(3) and californium(3) in solutions of 0.05-2.5 mol/l H2SO4 and HNO3 containing 10-3 mol/l potassium tungstophosphate is not practically oxidized by the mixture of silver nitrate and ammonium persulfate. Americium(3) is oxidized to the utmost to Am(4) for 2-3 min at room temperature, but stability of Am(4) depends on the concentration of sulfuric acid and potassium tungstophosphate

  20. Transuranic separation using organophophorus extractants adsorbed onto superparamagnetic carriers

    International Nuclear Information System (INIS)

    Polymeric coated ferromagnetic carriers with an absorbed layer of octyl(phenyl)-N,N-diisobutylcarbamoylmethylphosphine oxide (CMPO) diluted by tributyl phosphate (TBP) are being evaluated for application in the separation and the recovery of low concentrations of americium, plutonium, and uranium from nuclear waste solutions. Due to their chemical nature, these extractants selectively complex americium and plutonium contaminants onto the particles and the complexed particles can be recovered from the solution using a magnet. Physical and chemical characterization of the extractant-absorbed particles were performed by gamma and liquid scintillation counting, scanning electron microscopic (SEM) micrograph, and other physical measurements. Plutonium, americium, and uranium separations have been performed at various HNO3 and HCl concentrations. Parameters were studied to determine the limitations and capacity of the process. The status of the chemistry and application of the process to Department of Energy (DOE) remediation efforts for actinide decontamination are discussed

  1. Recovery of trans-plutonium elements

    International Nuclear Information System (INIS)

    The object of this work is to study the recovery of americium and curium from the fission-product solution obtained from the processing of irradiated fuel elements made of natural metallic uranium alloyed with aluminium, iron and silicon; these elements have been subjected to an average irradiation of 4000 MW days/ton in a gas-graphite type reactor having a thermal power of 3.7 MW/ton of uranium. The process used consists of 3 extraction cycles and one americium-curium separation: - 1) extraction cycle in 40 per cent TBP: extraction of actinides and lanthanides; elimination of fission products; - 2) extraction cycle in 8 per cent D2EHPA: decontamination from the fission products, decontamination of actinides from lanthanides; - 3) extraction cycle in 40 per cent TBP: separation of the complexing agent and concentration of the actinides; - 4) americium-curium separation by precipitation. (authors)

  2. Electroprecipitation of potassium americyl carbonate from potassium carbonate solutions

    International Nuclear Information System (INIS)

    Precipitation of potassium americyl carbonate was carried out at multigram scale by oxidizing at platinum anode Am(III) in 3 M K2CO3 solutions. Early investigations were conducted on pure americium 241 solutions on 10 to 40 mg scale, in order to study the different parameters of the electrolysis, and to prove the faisability of the process. Further experiments have been performed on the 20 grams scale, in impure americium 241 solutions. Electrolysis performed at 600C with platinum grid as anode, and tantalum rod immersed in a cathodic compartment, precipitates 20 grams of americium 241 with yields above 99% in two hours. The electroprecipitation process presents the advantage to be clean and suitable for automation technique in comparison with the chemical oxidation process using potassium persulfate

  3. Facilities for preparing actinide or fission product-based targets

    CERN Document Server

    Sors, M

    1999-01-01

    Research and development work is currently in progress in France on the feasibility of transmutation of very long-lived radionuclides such as americium, blended with an inert medium such as magnesium oxide and pelletized for irradiation in a fast neutron reactor. The process is primarily designed to produce ceramics for nuclear reactors, but could also be used to produce targets for accelerators. The Actinide Development Laboratory is part of the ATALANTE complex at Marcoule, where the CEA investigates reprocessing, liquid and solid waste treatment and vitrification processes. The laboratory produces radioactive sources; after use, their constituents are recycled, notably through R and D programs requiring such materials. Recovered americium is purified, characterized and transformed for an experiment known as ECRIX, designed to demonstrate the feasibility of fabricating americium-based ceramics and to determine the reactor transmutation coefficients.

  4. Accumulation of 241Am by suspended matter, diatoms and aquatic weeds of the Yenisei River

    International Nuclear Information System (INIS)

    In this work we experimentally estimated the capacities of the key components of the Yenisei River (Russia): particulate suspended matter (seston), diatom microalgae, and submerged macrophytes for accumulating 241Am from water. In our experiments large particles of seston (>8 μm), comparable in size with diatoms, took up most of americium from water. The accumulation of americium by isolated diatom algae (Asterionella formosa and Diatoma vulgare) was lower than by total seston. The concentration factors (CFs) of 241Am for seston of the Yenisei River in our experiments were (2.8-6.9).105; for diatoms - (1.5-4.2).104. The CFs for aquatic plant Elodea canadensis were within the same order of magnitude as those for diatoms. Activity concentration and CFs of 241Am were nearly the same in experiments under dark and light conditions. This is indicative of an energy independent mechanism of americium uptake from the water by diatoms and submerged macrophytes.

  5. Volatile species retention during metallic fuel casting

    Energy Technology Data Exchange (ETDEWEB)

    Fielding, Randall S., E-mail: randall.fielding@inl.gov; Porter, Douglas L.

    2013-10-15

    Metallic nuclear fuels are candidate transmutation fuel forms for advanced fuel cycles. Through the operation of the Experimental Breeder Reactor II metallic nuclear fuels have been shown to be robust and easily manufactured. However, concerns have been raised concerning loss of americium during the casting process because of its high vapor pressure. In order to address these concerns a gaseous diffusion model was developed and a series of experiments using both manganese and samarium as surrogates for americium were conducted. The modeling results showed that volatility losses can be controlled to essentially no losses with a modest overpressure. Experimental results also showed volatile species retention down to no detectable losses through overpressure, and although the loss values varied from the model results the same trend was seen. Based on these results it is very probable that americium losses through volatility can be controlled to no detectable losses through application of a modest overpressure during casting.

  6. Consideration of uncertain nuclear data in the computation of the reduction of waste actinides by irradiation

    International Nuclear Information System (INIS)

    The most promising physical measure for quantity reduction of long-lived radiation sources and thus for the reduction of long-term risks at the ultimate store is further irradiation of the waste actinide nuclides in the neutron field of the reactor. In order to determine whether the nuclear data base now available on waste actinides (neptunium 237, plutonium 238, americium 241, americium 242, and americium 243) allows even now the actual design of reactors for further irradiation of such actinides, burn-up calculations must be made taking into consideration the uncertain character of nuclear data. For this purpose, an improved method for the computation of error propagation had to be elaborated. (orig./DG)

  7. Speciation of U and Am in sol-gel derived borosilicate glasses by photoluminescence lifetime spectroscopy

    International Nuclear Information System (INIS)

    Borosilicate glasses are intended to be the barrier in between the high level nuclear waste and the geosphere. The oxidation state and the coordination geometry of a particular element in the glass influences its solubility, migration and complexation behavior, which in turn influences its long term leaching behavior. In this context, uranium and americium containing barium borosilicate glasses were prepared by sol-gel route and the speciation studies of U and Am in the glasses were carried out using photoluminescence lifetime spectroscopic technique. It was observed that in the matrix the uranium is stabilised as (UO6)6- and the americium as Am3+. (author)

  8. Actinide removal from nitric acid waste streams

    International Nuclear Information System (INIS)

    Actinide separations research at the Rocky Flats Plant (RFP) has found ways to significantly improve plutonium secondary recovery and americium removal from nitric acid waste streams generated by plutonium purification operations. Capacity and breakthrough studies show anion exchange with Dowex 1x4 (50 to 100 mesh) to be superior for secondary recovery of plutonium. Extraction chromatography with TOPO(tri-n-octyl-phosphine oxide) on XAD-4 removes the final traces of plutonium, including hydrolytic polymer. Partial neutralization and solid supported liquid membrane transfer removes americium for sorption on discardable inorganic ion exchangers, potentially allowing for non-TRU waste disposal

  9. Kinetic aspects of the behavior of a continuous electrolyzer dedicated to actinides and lanthanides oxidation applied to their separation

    International Nuclear Information System (INIS)

    As part of SESAME developments, a continuous electrochemical reactor has been tested for the in-line oxidation of various species as americium, ruthenium or cerium. The cerium(III) case has been chosen as a model to develop a predictive kinetic modeling of the reactor performances for oxidations. The optimal effect of an oxidation mediator may be described and the importance of some parameters was pointed out like the residence time, the anode material and the concentrations ratio between the substrate to oxidize and the mediator. This modeling will be extrapolated to the optimal electrolyzer design for the americium oxidation in the presence of lacunary heteropolyanions. (authors)

  10. Transuranium element production. II. Chemical processing of targets

    International Nuclear Information System (INIS)

    The chemical processing described concerns small experimental targets irradiated in OSIRIS or EL-III and industrial targets irradiated in the CELESTIN reactors. In view of the difficulties encountered when processing highly irradiated targets (760MWd.kg-1) by liquid-liquid extraction (interface sludges leading to stable emulsion) the new processes developed are based on inverse phase chromatography. This technique applied to targets of americium 241, plutonium 239 and a plutonium mixture rich in isotope 242 has given tens of milligrams of curium 242, grams of americium 243 and curium 244 and micrograms of californium 252

  11. Isolation of actinides and lanthanides by flotation from nitric acid solutions in the form of the complexes with diphosphinedioxides

    International Nuclear Information System (INIS)

    Isolation of europium, plutonium (4) and americium by ionic flotation from nitric acid solutions (1-5 mol/l HNO3), using diphosphinedioxides as surfactant-precipitator, was investigated. Increase in the metal isolation degree with an increase in flotation agent consumption was ascertained. When flotation agent is in excess, required for precipitation completeness, the metals studied are noticeably extracted from moderately concentrated solutions of nitric acid (3-3.5 mol/l), moreover, tolyl-containing diphosphinedioxide per one flotation operation extracts ∼90 % of plutonium, ∼75 % of americium and >75 % of europium

  12. Colloid formation during waste form reaction: implications for nuclear waste disposal

    Science.gov (United States)

    Bates, J. K.; Bradley, J.; Teetsov, A.; Bradley, C. R.; ten Brink, Marilyn Buchholtz

    1992-01-01

    Insoluble plutonium- and americium-bearing colloidal particles formed during simulated weathering of a high-level nuclear waste glass. Nearly 100 percent of the total plutonium and americium in test ground water was concentrated in these submicrometer particles. These results indicate that models of actinide mobility and repository integrity, which assume complete solubility of actinides in ground water, underestimate the potential for radionuclide release into the environment. A colloid-trapping mechanism may be necessary for a waste repository to meet long-term performance specifications.

  13. Development and validation of the EXAm separation process for single Am recycling

    International Nuclear Information System (INIS)

    The EXAm process aims at recovering americium alone. The principle of the EXAm process is based on the extraction of americium together with some light lanthanides having close values of distribution coefficients in high nitric acidity, while curium and other lanthanides remain in the aqueous phase. The TEDGA amide molecule is added in the aqueous phase to increase Am/Cm and Am/heavy Ln selectivity, because of the preferential complexation of curium and heavy lanthanides by this diglycolamide. The Am is subsequently selectively stripped from the light lanthanides. The full approach aiming at validating this complex process is illustrated in this paper. (authors)

  14. Sequential radiochemical separations from Alpine Wetland soils (Boreon, France) with emphasis on 90Sr measurement

    International Nuclear Information System (INIS)

    A radiochemical procedure to extract plutonium, americium and strontium from soils is presented. Strontium was separated from americium and plutonium fraction at the beginning of the method to increase the Sr recovery. The studied soils coming from an Alpine wetland site contain a big amount of iron which was eliminated by an oxalate precipitation before the column step. The hydroxide precipitation should be made by adding iron of known quantity to avoid interference. The procedure was validated by reference soils from IAEA. Plutonium-238, 239, 240, 241Am, 90Sr and 137Cs activities are given and some isotopic ratios are calculated in order to know the origin of the radionuclides. (author)

  15. The influence of temperature on migration of radionuclides in deep-sea sediments: Simulation experiments concerning sorption and heat flow related to deep-sea disposal of high-level radioactive waste

    International Nuclear Information System (INIS)

    This report presents the results of a study on the effects of temperatures up to 900C on the migration of the radionuclides plutonium, neptunium and americium through marine sediments in the near field of a canister with radioactive waste. Topics entered were; (i) the influence of temperature on the distribution coefficients of the transuranics plutonium, americium and neptunium, (ii) the effect of temperature on the composition and characteristics of interstitial water and (iii) the effects of a point heat source on the temperature distributions and flow velocities in interstitial water of sediments. (Auth.)

  16. Isolating 241Am from waste solutions containing Al, Ca, Fe, and Cr

    International Nuclear Information System (INIS)

    About 2.4 kg of 241Am contaminated with calcium and aluminum had been recovered from low-activity waste during recycle of 11% 240Pu. A process was developed and demonstrated to purify the americium before shipment as 241AmO2. The americium and some of the calcium were batch extracted into 50% TBP-n-paraffin from 2.2M Al(NO3)3 - 0.3M HNO3 solution in a canyon tank. Pregnant solvent was scrubbed first with 2.1M Al3+-0.3M Li+-6.7M NO3- and then with 7M LiNO3 to reduce the calcium content and to displace the aluminum. Americium was then stripped from the solvent with water and concentrated by evaporation. Before precipitating the americium with oxalic acid, the nitric acid was adjusted with NH4OH to yield a 1M NH4NO3 solution. Recovery across the batch extraction step was 97.8%, while 93% of the calcium and >99% of the aluminum was rejected. Recovery across precipitation averaged >96% while producing a product which was >99.3% pure 241AmO2. The major impurities were water, carbon, calcium, iron, and zinc

  17. Coordination chemistry of several radius-sensitive complexones and applications to lanthanide-actinide separations

    International Nuclear Information System (INIS)

    The relationships between the lanthanide complex formation equilibria and the lanthanide-actinide separation application of three radius sensitive ligands have been studied. The consecutive stepwise formation constants of the 1:1, 2:1, and 3:1 chelate species formed by the interaction of DHDMB and the tripositive lanthanides and yttrium were determined potentiometrically at 0.1 M ionic strength and 250C. Results indicate that three different coordination modes, one tridentate and two bidentate are in evidence. Tracer level 241Am - 155Eu cation-exchange experiments utilizing DHDMB eluents indicate that this dihydroxycarboxylate does not form a sufficiently strong americium complex to elute that actinide ahead of europium. The overall stability of the americium 3:1 complex appears intermediate between samarium and europium. Cation-exchange elutions of 241Am, 155Eu, and 160Tb mixtures with EEDTA solutions prove that the EEDTA ligand is capable of eluting americium ahead of all of the tripositive lanthanide cations. The minimum separation occurs with terbium, where the Am-Tb separation factor is 1.71. 1,5-diaminopentane-N,N,N',N'-tetraacetic acid (PMDTA) was synthesized using cation exchange. A mathematical method was developed for the formation constants of the protonated and unprotonated lanthanide-PMDTA complexes from potentiometry. Cation-exchange elutions of tracer quantities of Am, Eu, and Tb revealed that terbium is eluted ahead of both americium and europium

  18. Radiological analysis of materials sampled on the old nuclear test site of In Ekker (Algeria); Analyses radiologiques de materiaux preleves sur l'ancien site d'essais nucleaires d'In Ekker (Algerie)

    Energy Technology Data Exchange (ETDEWEB)

    Chareyron, Bruno

    2010-02-11

    After having recalled the context of the French nuclear test campaign in Algeria between 1961 and 1966, this document reports and comments radiological measurements performed on the site of In Ekker, and also results of analysis performed in laboratory (contamination by cesium 137, americium 241, plutonium); recommendations are given

  19. Report on the scientifical feasibility of advanced separation

    International Nuclear Information System (INIS)

    The advanced separation process Purex has been retained for the recovery of neptunium, technetium and iodine from high level and long lived radioactive wastes. Complementary solvent extraction processes will be used for the recovery of americium, curium and cesium from the high activity effluents of the spent fuel reprocessing treatment. This document presents the researches carried out to demonstrate the scientifical feasibility of the advanced separation processes: the adaptation of the Purex process would allow the recovery of 99% of the neptunium, while the association of the Diamex and Sanex (low acidity variant) processes, or the Paladin concept (single cycle with selective de-extraction of actinides) make it possible the recovery of 99.8% of the actinides III (americium and curium) with a high lanthanides decontamination factor (greater than 150). The feasibility of the americium/curium separation is demonstrated with the Sesame process (extraction of americium IV after electrolytic oxidation). Iodine is today recovered at about 99% with the Purex process and the dissolved fraction of technetium is also recovered at 99% using an adaptation of the Purex process. The non-dissolved fraction is retained by intermetallic compounds in dissolution residues. Cesium is separable from other fission products with recovery levels greater than 99.9% thanks to the use of functionalized calixarenes. The scientifical feasibility of advanced separation is thus demonstrated. (J.S.)

  20. Presence and Character of the 5f Electrons in the Actinide Metals

    DEFF Research Database (Denmark)

    Johansson, B.; Skriver, Hans Lomholt; Mårtensson, N.;

    1980-01-01

    The sensitivity of the Image level binding energy to the occupation of the 5f orbital is pointed out and used to demonstrate the presence of 5f electrons in the uranium metal. It is suggested that the valence band spectrum of uranium might contain satellites originating from excitations to locali...... and the critical separation is found to take place between plutonium and americium....

  1. Electronic Structure of the Actinide Metals

    DEFF Research Database (Denmark)

    Johansson, B.; Skriver, Hans Lomholt

    1982-01-01

    itinerant to localized 5f electron behaviour calculated to take place between plutonium and americium. From experimental data it is shown that the screening of deep core-holes is due to 5f electrons for the lighter actinide elements and 6d electrons for the heavier elements. A simplified model for the full...

  2. Literatuuronderzoek plutoniumanalyses

    NARCIS (Netherlands)

    Glastra P; Kwakman PJM; LSO

    1997-01-01

    This report describes recent developments in the radiochemical determination of plutonium in samples from the environment such as aerosols, rainwater, grass and soil. The radiochemical separation of plutonium from interfering alpha emitters, such as americium and curium, was found to be simplified b

  3. Isotopic ratios and effective power determined by gamma-ray spectroscopy vs mass spectroscopy for molten salt extraction residues

    International Nuclear Information System (INIS)

    Impure plutonium metal is routinely processed by molten salt extraction (MSE) to reduce the amount of americium in the metal product. Throughput at various facilities where similar processes are performed has made it essential to evaluate uncertainties and possible discrepancies in the analyses of these difficult MSE materials. In an effort to evaluate the plutonium isotopic ratios and americium concentrations obtained from gamma-ray spectral data analyzed by the computer code GRPAUT, measurements were made on ten MSE salts as received and after pulverization and blending. These results were then compared to the specific powers obtained from isotopic ratios determined by mass spectrometry on these same ten samples. Americium values ranged from a few thousand parts-per-million of total plutonium to greater than 50,000 ppM. Our results indicate a small discrepancy between specific powers as determined by GRPAUT on ''as received'' vs pulverized and blended MSE salts. The specific powers obtained via GRPAUT on the pulverized salts agree somewhat better with specific powers obtained from the mass spectroscopy data. This work may indicate that a small discrepancy exists in the specific powers by using GRPAUT on heterogeneous, high americium samples. 5 refs., 6 tabs

  4. Methodology of integrated land as containing transuranic

    International Nuclear Information System (INIS)

    The determination of the activity concentration of soil contaminated with transuranic on significant volumes is not trivial, is a technique that is necessary to evaluate the extent of large amounts of land (thousand m3) in restoration projects or to land contain americium or plutonium due to activities or incidents of the past.

  5. Methodology of integrated land as containing transuranic; Metodologia de medida integrada de tierras con contenido de transuranidos

    Energy Technology Data Exchange (ETDEWEB)

    Correa Garces, E.; Saez Vergara, J. C.; Burgos Garcia, D.; Sancho Llerandi, C.

    2011-07-01

    The determination of the activity concentration of soil contaminated with transuranic on significant volumes is not trivial, is a technique that is necessary to evaluate the extent of large amounts of land (thousand m3) in restoration projects or to land contain americium or plutonium due to activities or incidents of the past.

  6. Historical review of californium-252 discovery and development

    International Nuclear Information System (INIS)

    This paper discusses the discovery and history of californium 252. This isotope may be synthesized by irradiating plutonium 239, plutonium 242, americium 243, or curium 244 with neutrons in a nuclear reactor. Various experiments and inventions involving 252Cf conducted at the Savannah River Plant are discussed. The evolution of radiotherapy using californium 252 is reviewed

  7. A study on modeling and numerical simulation of extraction in the CMPO-TBP system

    International Nuclear Information System (INIS)

    A numerical simulation code for the TRUEX (Transuranium Extraction) process was developed. Concentration profiles of americium and europium were calculated for some experiments of the counter current extraction system those were carried out in CPF (Chemical Processing Facility) by using the code. Calculation profiles were in agreement with the experimental results. Operational conditions were also examined for the americium recovery experiment by the TRUEX process carried out in the Plutonium Fuel Center. It was shown that lowering the concentration of nitric acid in the scrub solution and decreasing the flow rate of solvent and strip solution was effective for improving the performance of the stripping step and reducing the volume of the waste solution. In order to find the optimum conditions for various experiments, this simulation code was modified to calculate the concentration profiles of other metal elements such as zirconium and iron and the effect of oxalic acid on the extraction behavior of the metal elements. The calculated concentration profiles of americium and europium were varied by this modification. In the experiment at CPF, the calculations were carried out to obtain recovery ratio of americium in the product stream with the amount of oxalic acid added to the process. This calculation result showed that it was possible to improve the performance of decontamination of fission products by increasing oxalic acid concentration added to the process. The calculation was also carried out for finding the optimum conditions of oxalic acid concentration added to the europium recovery process. (author)

  8. 75 FR 34774 - Notice of Availability of Environmental Assessment and Finding of No Significant Impact for...

    Science.gov (United States)

    2010-06-18

    ...-lives greater than 120 days: Barium 133, cesium 137, americium 241, and uranium 238. Prior to performing... 20 for unrestricted release. Because NRC has not established a screening value for barium 133, the licensee developed a DCGL for barium 133 for its Facility. The Licensee developed the barium 133 DCGL...

  9. Bidentate organophosphorus compounds as extractants from acidic waste solutions: a comparative and systematic study

    Energy Technology Data Exchange (ETDEWEB)

    Shoun, R.R.; McDowell, W.J.; Weaver, B.

    1977-01-01

    A comparative study has been made of several bidentate organophosphorus compounds. Tetraalkyl carbamoylmethylphosphonates and tetraalkylalkyl diphosphonates were tested for their ability to extract americium from nitric acid. Aromatic, aliphatic, and mixed diluents were compared as to the effect on extraction behavior, aqueous-phase solubility, and organic-phase solubility. Reagent and acid dependences are presented for selected compounds.

  10. Determination of 241Am and 244Cm in environmental samples

    International Nuclear Information System (INIS)

    The present technique describes a method to separate, purify and measure low levels of americium and curium in different environmental samples such as sediments, soils, water, vegetables, and air filters. The determination of radionuclides in theses environmental matrices have analytical problems, since a simple method doesn't exist for the purification, which is indispensable for its later measuring alpha spectrometry. The developed technique consist on taking an aliquot of the sample to analyze, to add tracer as americium 243 and curium 242, and to dissolve the matrix in a such way to have a clear solution. For the isolation of the americium and curium of the other actinides ar used as separation techniques: precipitation with Fe3+, anionic and cationic exchange, and extraction with a appropriate organic solvent. The purification of the americium and curium is followed by the electrodeposition habitually used. The measurement is carried out by alpha spectrometry with a detector of implanted ion. The detection limit for this techniques is of 0,002 Bq/l or 0,2 mBq in the case of filters. (author)

  11. The unique high-pressure behavior of curium probed further using alloys

    International Nuclear Information System (INIS)

    The changing role of the 5f electrons across the actinide series has been of prime interest for many years. The remarkable behavior of americium's 5f electrons under pressure was determined experimentally a few years ago and it precipitated a strong interest in the heavy element community. Theoretical treatments of americium's behavior under pressure followed and continue today. Experimental and theoretical findings regarding curium's behavior under pressure have shown that the pressure behavior of curium was not a mirror image of that for americium. Rather, one of the five crystallographic phases observed with curium (versus four for americium) was a unique monoclinic structure whose existence is due to a spin stabilization effect by curium's 5f7 electronic configuration and its half-filled 5f-shell. We review briefly the behavior of pure curium under pressure but focus on the pressure behaviors of three curium alloys with the intent of comparing them with pure curium. An important experimental finding confirmed by theoretical computations, is that dilution of curium with its near neighbors is sufficient to prevent the formation of the unique C2/c phase that appears in pure Cm metal under pressure. As this unique C2/c phase is very sensitive to having a 5f7 configuration to maximize the magnetic spin polarization, dilution of this state with adjacent actinide neighbors reduces its stability

  12. Chemical transformation kinetics of Pu and Am in soils of Belarus

    International Nuclear Information System (INIS)

    On the basis of available experimental data the constant of destruction rate of fuel particles and constants of formation rate of plutonium and americium fulvates which determine migration kinetics of metals - ions in a soil - plant system are calculated. The long-term forecast of accumulation of mobile forms of Pu and Am in soil is carried out. (authors)

  13. Fifteen years after accident

    International Nuclear Information System (INIS)

    This book is devoted to 15th anniversary of the Chernobyl accident. Four problems have been reflected in the book: contamination of territories of Western Europe, Belarus, Ukraine and Russian Federation by cesium-137; plutonium, americium and other actinides on territory of Belarus; problems of radioactive wastes management of Chernobyl origin; influence of various factors on oncology morbidity in the Republic of Belarus

  14. The Methods Sampling, Measurement and Analysis in Impression of Environment Radioactivity

    International Nuclear Information System (INIS)

    This document relates to radionuclides, analytic methods, analytic quality control, equipment and person el necessities for laboratories, gamma-ray spectroscopic method, radiostrontium and strontium-90, standard test method for tritium, strontium-89 and strontium-90, plutonium and americium, systems of international unit

  15. Estimates of dose to systematic organs and GI tract based on data from miniature swine orally intubated with a single dose of Am-241 citrate

    International Nuclear Information System (INIS)

    A model is presented for the internal radiation dose to the small intestine wall of miniature swine given Americium 241 citrate by oral intubation. The model incorporates the uptake of the Am-241 by the intestinal wall. About equal contributions of dose to the small intestine were observed from the intestinal contents and the wall itself

  16. Experimental findings on actinide recovery utilizing oxidation by peroxydisulfate followed by ion exchange: Fuel cycle research & development

    Energy Technology Data Exchange (ETDEWEB)

    Hobbs, D. T. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Shehee, T. C. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2015-08-31

    Our research seeks to determine if inorganic ion-exchange materials can be exploited to provide effective minor actinide (Am, Cm) separation from lanthanides. Previous work has established that a number of inorganic and UMOF ion-exchange materials exhibit varying affinities for actinides and lanthanides, which may be exploited for effective separations. During FY15, experimental work focused on investigating methods to oxidize americium in dilute nitric and perchloric acid with subsequent ion-exchange performance measurements of ion exchangers with the oxidized americium in dilute nitric acid. Ion-exchange materials tested included a variety of alkali titanates. Americium oxidation testing sought to determine the influence that other redox active components may have on the oxidation of AmIII. Experimental findings indicated that CeIII, NpV, and RuII are oxidized by peroxydisulfate, but there are no indications that the presence of CeIII, NpV, and RuII affected the rate or extent of americium oxidation at the concentrations of peroxydisulfate being used.

  17. Experimental findings on actinide recovery utilizing oxidation by peroxydisulfate followed by ion exchange: Fuel cycle research & development

    Energy Technology Data Exchange (ETDEWEB)

    Hobbs, D. T. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Shehee, T. C. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2015-08-31

    Our research seeks to determine if inorganic ion-exchange materials can be exploited to provide effective minor actinide (Am, Cm) separation from lanthanides. Previous work has established that a number of inorganic and UMOF ion-exchange materials exhibit varying affinities for actinides and lanthanides, which may be exploited for effective separations. During FY15, experimental work focused on investigating methods to oxidize americium in dilute nitric and perchloric acid with subsequent ion-exchange performance measurements of ion exchangers with the oxidized americium in dilute nitric acid. Ion-exchange materials tested included a variety of alkali titanates. Americium oxidation testing sought to determine the influence that other redox active components may have on the oxidation of AmIII. Experimental findings indicated that CeIII, NpV, and RuII are oxidized by peroxydisulfate, but there are no indications that the presence of CeIII, NpV, and RuII affected the rate or extent of americium oxidation at the concentrations of peroxydisulfate being used.

  18. Discovery of Isotopes of the Transuranium Elements with 93 <= Z <= 98

    OpenAIRE

    Fry, C; Thoennessen, M

    2012-01-01

    One hundred and five isotopes of the transuranium elements neptunium, plutonium, americium, curium, berkelium and californium have so far been observed; the discovery of these isotopes is discussed. For each isotope a brief summary of the first refereed publication, including the production and identification method, is presented.

  19. The complementary role of advanced fuel cycles and waste disposal

    International Nuclear Information System (INIS)

    The paper deals with possibilities to increase the waste disposal acceptability by separation of neptunium, americium and curium from high-level radioactive wastes. The author's remarks are mainly based on French studies. The second topic of the presentation deals with transmutation. (author) figs

  20. A Novel Experiment to Investigate the Attenuation of Alpha Particles in Air

    Science.gov (United States)

    Andrews, D. G. H.

    2008-01-01

    A simple student experiment investigating dependence on air pressure of the attenuation of alpha particles in air is described. An equation giving the pressure needed to absorb all alpha particles of a given energy is derived from the Bethe-Bloch formula. Results are presented for the attenuation of alpha particles from americium 241 and radium…