WorldWideScience

Sample records for americium 236

  1. 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)

  2. Accidental exposure to americium

    International Nuclear Information System (INIS)

    Heid, K.R.

    1985-04-01

    This report desribes an accident in which a 64-year old Hanford nuclear worker was exposed to high levels of americium while working in an americium recovery facility in 1976. As a result of the accident, he was heavily externally contaminated with americium, sustained with a substantial internal deposition of this isotope, and was burned with concentrated nitric acid and injured by flying debris about the face and neck. The immediate and longer-term treatment given the patient, including the decontamination efforts and clinical laboratory studies, are discussed. Special in-vivo equipment and techniques were used to measure the americium deposited in the patient. These and subsequent in-vivo measurements were used to estimate the dose rates and the accumulated doses to body organs. Urinary and fecal excreta were collected and analyzed for americium content. The interpretation of these data was complicated by the fact that the intake resulted both from inhalation and from solubilization of the americium embedded in facial tissues as a result of the accident. A total of 1100 μCi was excreted in urine and feces during the first 2 years following the accident. The long-term use of diethylenetriaminepentaacetic acid (DTPA), used principally as the zinc salt, is discussed including the method, route of administration, and effectiveness. To date, the patient has apparently experienced no complications attributable to this extensive course of therapy, even though he was given approximately 560 g of DTPA. 6 refs

  3. Determination of americium in urine

    International Nuclear Information System (INIS)

    Shvydko, N.S.; Mikhajlova, O.A.; Popov, D.K.

    1988-01-01

    A technique has been developed for the determination of americium 241 in urine by a raiochemical purification of the nuclide from uranium (upon co-precipitation of americium 241 with calcium and lanthanum), plutonium, thorum, and polonium 210 (upon co-precipitation of these radionuclides with zirconium iodate). α-Radioactivity was measured either in a thick layer of the americium 241 precipitate with a nonisotope carrier or in thin-layer preparations after electrolytic precipitation of americium 241 on a cathode

  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. 1976 Hanford americium accident

    International Nuclear Information System (INIS)

    Heid, K.R.; Breitenstein, B.D.; Palmer, H.E.; McMurray, B.J.; Wald, N.

    1979-01-01

    This report presents the 2.5-year medical course of a 64-year-old Hanford nuclear chemical operator who was involved in an accident in an americium recovery facility in August 1976. He was heavily externally contaminated with americium, sustained a substantial internal deposition of this isotope, and was burned with concentrated nitric acid and injured by flying debris about the face and neck. The medical care given the patient, including the decontamination efforts and clinical laboratory studies, are discussed. In-vivo measurements were used to estimate the dose rates and the accumulated doses to body organs. Urinary and fecal excreta were collected and analyzed for americium content. Interpretation of these data was complicated by the fact that the intake resulted both from inhalation and from solubilization of the americium embedded in facial tissues. A total of 1100 μCi was excreted in urine and feces during the first 2 years following the accident. The long-term use of diethylenetriaminepentate (DTPA), used principally as the zinc salt, is discussed including the method, route of administration, and effectiveness. To date, the patient has apparently experienced no complications attributable to this extensive course of therapy, even though he has been given approximately 560 grams of DTPA. 4 figures, 1 table

  6. On the americium oxalate solubility

    International Nuclear Information System (INIS)

    Zakolupin, S.A.; Korablin, Eh.V.

    1977-01-01

    The americium oxalate solubility at different nitric (0.0-1 M) and oxalic (0.0-0.4 M) acid concentrations was investigated in the temperature range from 14 to 60 deg C. The dependence of americium oxalate solubility on the oxalic acid concentration was determined. Increasing oxalic acid concentration was found to reduce the americium oxalate solubility. The dependence of americium oxalate solubility on the oxalic acid concentration was noted to be a minimum at low acidity (0.1-0.3 M nitric acid). This is most likely due to Am(C 2 O 4 ) + , Am(C 2 O 4 ) 2 - and Am(C 2 O 4 ) 3 3- complex ion formation which have different unstability constants. On the basis of the data obtained, a preliminary estimate was carried out for the product of americium oxalate solubility in nitric acid medium (10 -29 -10 -31 ) and of the one in water (6.4x10 -20 )

  7. Recycling of americium

    International Nuclear Information System (INIS)

    Hagstroem, Ingela

    1999-12-01

    Separation of actinides from spent nuclear fuel is a part of the process of recycling fissile material. Extracting agents for partitioning the high level liquid waste (HLLW) from conventional PUREX reprocessing is studied. The CTH-process is based on three consecutive extraction cycles. In the first cycle protactinium, uranium, neptunium and plutonium are removed by extraction with di-2-ethylhexyl-phosphoric acid (HDEHP) from a 6 M nitric acid HLLW solution. Distribution ratios for actinides, fission products and corrosion products between HLLW and 1 M HDEHP in an aliphatic diluent have been investigated. To avoid addition of chemicals the acidity is reduced by a tributylphosphate (TBP) extraction cycle. The distribution ratios of elements present in HLLW have been measured between 50 % TBP in an aliphatic diluent and synthetic HLLW in range 0.1-6 M nitric acid. In the third extraction cycle americium and curium are extracted. To separate trivalent actinides from lanthanides a method based on selective stripping of the actinides from 1 M HDEHP is proposed. The aqueous phase containing ammonia, diethylenetriaminepentaacetic acid (DTPA) and lactic acid is recycled in a closed loop after reextraction of the actinides into a second organic phase also containing 1 M HDEHP. Distribution ratios for americium and neodymium have been measured at varying DTPA and lactic acid concentrations and at varying pH. Nitrogen-donor reagents have been shown to have a potential to separate trivalent actinides from lanthanides. 2,2':6,2''-terpyridine as extractant follows the CHON-principle and can in synergy with 2-bromodecanoic acid separate americium from europium. Distribution ratios for americium and europium, in the range of 0.02-0.12 M nitric acid, between nitric acid and 0.02 M terpyridine with 1 M 2-bromodecanoic acid in tert-butylbenzene (TBB) was investigated. Comparison with other nitrogen-donor reagents show that increasing lipophilicity of the molecule, by substitution of

  8. Americium-241 - ED 4308

    International Nuclear Information System (INIS)

    Ammerich, M.; Frot, P.; Gambini, D.; Gauron, C.; Moureaux, P.; Herbelet, G.; Lahaye, T.; Le Guen, B.; Pihet, P.; Rannou, A.; Vidal, E.

    2012-12-01

    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)

  9. Americium product solidification and disposal

    International Nuclear Information System (INIS)

    Mailen, J.C.; Campbell, D.O.; Bell, J.T.; Collins, E.D.

    1987-01-01

    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

  10. Americium in the Finnish environment

    Energy Technology Data Exchange (ETDEWEB)

    Lehto, J. (Helsinki Univ., Lab. of Radiochemistry (Finland))

    2009-07-01

    This paper reviews studies on environmental americium,241 Am, in Finland. There are two sources of americium in the Finnish environment: fallouts from nuclear weapons tests in the 1950s and 1960s and from the Chernobyl accident in 1986, the former constituting around 98% of the total environmental load. The weapons test fallout was distributed more or less uniformly over Finland, while the Chernobyl fallout was deposited on a sector from southwestern coast to northeast. The total deposition of 241 Am in Finland is approximately 20 Bq m-2 and the amount is still somewhat increasing due to decay of 241 Pu. In this paper, the distribution and migration of americium in forest and aquatic environments is described. Americium concentrations in natural waters, sediments, soils, vegetation and fishes are given. In addition, the behaviour of americium in the food chain from lichen via reindeer into man is discussed. Radiation doses to humans due to the environmental americium in Finland are of no practical importance (orig.)

  11. Plutonium and americium separation from salts

    International Nuclear Information System (INIS)

    Hagan, P.G.; Miner, F.J.

    1976-01-01

    Salts or materials containing plutonium and americium are dissolved in hydrochloric acid, heated, and contacted with an alkali metal carbonate solution to precipitate plutonium and americium carbonates which are thereafter readily separable from the solution

  12. Isolation of high purity americium metal via distillation

    Science.gov (United States)

    Squires, Leah N.; King, James A.; Fielding, Randall S.; Lessing, Paul

    2018-03-01

    Pure americium metal is a crucial component for the fabrication of transmutation fuels. Unfortunately, americium in pure metal form is not available; however, a number of mixed metals and mixed oxides that include americium are available. In this manuscript a method is described to obtain high purity americium metal from a mixture of americium and neptunium metals with lead impurity via distillation.

  13. 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...

  14. Analysis of Americium in Transplutonium Process Solutions

    International Nuclear Information System (INIS)

    Ferguson, R.B.

    2001-01-01

    One of the more difficult analyses in the transplutonium field is the determination of americium at trace levels in a complex matrix such as a process dissolver solution. Because of these conditions a highly selective separation must precede the measurement of americium. The separation technique should be mechanically simple to permit remote operation with master-slave manipulators. For subsequent americium measurement by the mass spectroscopic isotopic-dilution technique, plutonium and curium interferences must also have been removed

  15. Metabolism of americium-241 in dairy animals

    International Nuclear Information System (INIS)

    Sutton, W.W.; Patzer, R.G.; Mullen, A.A.; Hahn, P.B.; Potter, G.D.

    1978-10-01

    Groups of lactating cows and goats were used to examine americium-241 metabolism in dairy animals. Following either single oral or intravenous nuclide doses, samples of milk, urine, blood, and feces were taken over a 168-hr collection period and the americium concentrations were determined by gamma counting. Gastrointestinal uptake of americium by both cows and goats was estimated to be 0.014% of the respective oral doses. The cumulative percentage of oral dose transported to milk and urine was 4.4 x 10 -4 and 1.1 x 10 -3 respectively for cows and 4.4 x 10 -3 and 1.2 x 10 -3 respectively for goats. The relatively high americium concentrations noted in caprine milk following the oral doses are discussed. Plasma concentrations of americium decreased rapidly following all intravenous injections. The average percentage of injected americium transferred to milk, urine, and feces was 3, 6, and 2% respectively for cows and 2, 4, and 2% respectively for goats. In both intravenously dosed groups, approximately 30% of all americium released from the body was found in the urine during the first 24 hrs after injection. All animals were sacrificed 8 to 9 days after dosing. Bovine bone retained the greatest fraction of the administered dose followed by the liver. However, liver retained the greatest amount of americium in the goats following both oral and intravenous doses. Comparisons are presented between americium-241 and plutonium-238 transport in dairy cows

  16. Metabolism of americium-241 in dairy animals

    International Nuclear Information System (INIS)

    Sutton, W.W.; Patzer, R.G.; Mullen, A.A.; Hahn, P.B.; Potter, G.D.

    1978-01-01

    Groups of lactating cows and goats were used to examine americium-241 metabolism in dairy animals. Following either single oral or intravenous nuclide doses, samples of milk, urine, blood, and feces were taken over a 168-hour collection period, and the americium concentrations were determined by gamma counting. Gastrointestinal uptake of americium by cows and goats was estimated to be 0.014 and 0.016% of the oral dose, respectively. The cumulative percentage of oral dose transported to milk and urine was 4.4 x 10 -4 and 1.1 x 10 -3 , respectively, for cows and 5.6 x 10 -4 and 1.2 x 10 -3 , respectively, for goats. Plasma concentrations of americium decreased rapidly following all intravenous injections. The average percentage of injected americium transferred to milk, urine, and feces was 3, 6, and 2%, respectively, for cows, and 2, 4, and 2%, respectively, for goats. In both intravenously dosed groups, approximately 30% of all americium released from the body was found in the urine during the first 24 hours after injection. All animals were sacrificed 8 to 9 days after dosing. Bovine bone retained the greatest fraction of the administered dose followed by liver and kidney. However, liver retained the greatest amount of americium in the goats following both oral and intravenous doses. Comparisons are presented between americium-241 and plutonium-238 transport in dairy cows

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

    International Nuclear Information System (INIS)

    Trebunova, T.

    1999-01-01

    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-Spec TM .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

  18. Production of americium isotopes in France

    International Nuclear Information System (INIS)

    Koehly, G.; Bourges, J.; Madic, C.; Nguyen, T.H.; Lecomte, M.

    1984-12-01

    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 SiO 2 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 HNO 3 at room temperature. The separation between plutonium and americium is performed by extraction of Pu(IV) either on TBP/SiO 2 or TOAHNO 3 /SiO 2 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/SiO 2 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 AmO 2 final product indicates a purity better than 98.5%

  19. Contributions to the preparation of 241americium metal and a few 241americium silicides

    International Nuclear Information System (INIS)

    Wittmann, F.D.

    1980-01-01

    In order to take a closer look at the americium-silicon system, three further silicides of americium: Am 5 Si 3 , Am 2 Si 3 and AmSi 2 were prepared in addition to the already known americium monosilicide and starting from the knowledge gained from the latters preparation. Radiographic investigations were carried out into the temperature region of 900 0 C. They showed no change of structure in the three compounds. It was possible to prepare residue-free americium metal by reducing AmF 3 with Si, whereby the SiF 4 formed can be easily separated off as volatile compound, and the Am metal is brought into a very pure form by sublimation suitable for spectrochemical investigations. Attempts to prepare binary germanides and gallides of 241 americium were unsuccessful. (RB) [de

  20. Americium removal from nitric acid waste streams

    International Nuclear Information System (INIS)

    Muscatello, A.C.; Navratil, J.D.

    1986-01-01

    Separations research at the Rocky Flats Plant (RFP) has found ways to significantly improve americium removal from nitric acid (7M) waste streams generated by plutonium purification operations. Partial neutralization of the acid waste followed by solid supported liquid membranes (SLM) are useful in transferring and concentrating americium from nitrate solutions. Specifically, DHDECMP (dihexyl-N,N-diethylcarbamoylmethylphosphonate) supported on Accurel polypropylene hollow fibers assembled in modular form transfers >95% of the americium from high nitrate (6.9M), low acid (0.1M) feeds into 0.25M oxalic acid stripping solution. Maximum permeabilities were observed to be 0.001 cm/sec, consistent with typical values for other systems. The feed:strip volume ratio shows an inverse relationship to the fraction of metal ion transferred. Cation exchangers may be used to concentrate americium from the strip solution. Furthermore, O0D (iB)CMPO (or CMPO) (octylphenyl-N-N-diisobutylcarbamoylmethylphosphine oxide) has been tested in an extraction chromatography mode. Preliminary results show CMPO to be effective in removing americium if the feed is neutralized to 1.0M acidity and iron(III) is complexed with 0.20M oxalic acid. 3 figs

  1. Americium thermodynamic data for the EQ3/6 database

    International Nuclear Information System (INIS)

    Kerrisk, J.F.

    1984-07-01

    Existing thermodynamic data for aqueous and solid species of americium have been reviewed and collected in a form that can be used with the EQ3/6 database. Data that are important in solubility calculations for americium at a proposed Yucca Mountain nuclear waste repository were emphasized. Conflicting data exist for americium complexes with carbonates. Essentially no data are available for americium solids or complexes at temperatures greater than 25 0 C. 17 references, 4 figures

  2. 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.

  3. Formation of americium and europium humate complexes

    International Nuclear Information System (INIS)

    Minai, Y.; Tominaga, T.; Meguro, Y.

    1991-01-01

    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 241 Am or 152 Eu 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)

  4. Biosorption of americium by alginate beads

    International Nuclear Information System (INIS)

    Borba, Tania Regina de; Marumo, Julio Takehiro; Goes, Marcos Maciel de; Ferreira, Rafael Vicente de Padua; Sakata, Solange Kazumi

    2009-01-01

    The use of biotechnology to remove heavy metals from wastes plays great potential in treatment of radioactive wastes and therefore the aim of this study was to evaluate the biosorption of americium by alginate beads. Biosorption has been defined as the property of certain biomolecules to bind and remove selected ions or other molecules from aqueous solutions. The calcium alginate beads as biosorbent were prepared and analyzed for americium uptaking. The experiments were performed in different solution activity concentrations, pH and exposure time. The results suggest that biosorption process is more efficient at pH 4 and for 75, 150, 300 Bq/mL and 120 minutes were necessary to remove almost 100% of the americium-241 from the solution. (author)

  5. Transmutation of Americium in Fast Neutron Facilities

    International Nuclear Information System (INIS)

    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 core's safety parameters. Applying the SAS4A/SASSYS transient analysis code, it is demonstrated that the power rating needs to be reduced by 6% for each percent additional americium introduction into the reference MOX fuel, maintaining 100 K margin to fuel melting, which is the most limiting failure mechanism. Safety analysis of a new Accelerator Driven System design with a smaller pin pitch-to-diameter ratio comparing to the reference EFIT-400 design, aiming at improving neutron source efficiency, was also performed by simulating performance for unprotected loss of flow, unprotected transient overpower, and protected loss-of-heat-sink transients, using neutronic parameters obtained from MCNP calculations. Thanks to the introduction of the austenitic 15/15Ti stainless steel with enhanced creep rupture resistance and acceptable irradiation swelling rate, the suggested ADS design loaded with nitride fuel and cooled by lead-bismuth eutectic could survive the full set of transients, preserving a margin of 130 K to cladding rupture during the most limiting transient. The thesis concludes that efficient transmutation of americium in a medium sized sodium cooled fast reactor loaded with MOX fuel is possible but leads to a severe power penalty. Instead, preserving transmutation rates of minor actinides up to 42 kg/TWh th , the suggested ADS design with enhanced proton source efficiency appears like a better option for americium transmutation

  6. Preparation of americium source for smoke detector

    International Nuclear Information System (INIS)

    Ramaswami, A.; Singh, R.J.; Manohar, S.B.

    1994-01-01

    This report describes the method developed for the preparation of 241 Am 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 241 Am 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

  7. Redox chemistry of americium in nitric acid media

    Energy Technology Data Exchange (ETDEWEB)

    Picart, S.; Jobelin, I.; Armengol, G.; Adnet, JM

    2004-07-01

    The redox properties of the actinides are very important parameters for speciation studies and spent nuclear fuel reprocessing based on liquid-liquid extraction of actinides at different oxidation states (as in the Purex or Sesame process). They are also very useful for developing analytical tools including coulometry and redox titration. This study addressed the americium(IV)/americium(III) and americium(VI)/americium(V) redox couples, focusing on exhaustive acquisition of the thermodynamic and kinetic parameters of americium oxidation at an electrode in a complexing nitric acid medium. (authors)

  8. Redox chemistry of americium in nitric acid media

    International Nuclear Information System (INIS)

    Picart, S.; Jobelin, I.; Armengol, G.; Adnet, JM.

    2004-01-01

    The redox properties of the actinides are very important parameters for speciation studies and spent nuclear fuel reprocessing based on liquid-liquid extraction of actinides at different oxidation states (as in the Purex or Sesame process). They are also very useful for developing analytical tools including coulometry and redox titration. This study addressed the americium(IV)/americium(III) and americium(VI)/americium(V) redox couples, focusing on exhaustive acquisition of the thermodynamic and kinetic parameters of americium oxidation at an electrode in a complexing nitric acid medium. (authors)

  9. Americium separations from high salt solutions

    International Nuclear Information System (INIS)

    Barr, Mary E.; Jarvinen, Gordon D.; Schulte, Louis D.; Stark, Peter C.; Chamberlin, Rebecca M.; Abney, Kent D.; Ricketts, Thomas E.; Valdez, Yvette E.; Bartsch, Richard A.

    2000-01-01

    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

  10. 1976 Hanford americium exposure incident: psychological aspects

    International Nuclear Information System (INIS)

    Brown, W.R.

    1982-01-01

    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

  11. Transmutation of americium in critical reactors

    International Nuclear Information System (INIS)

    Wallenius, J.

    2005-01-01

    Already in 1974, a Los Alamos report suggested that the recycling of higher actinides would be detrimental for the safety of critical reactors. Later investigations confirmed this understanding, and stringent limits on the fraction of minor actinides allowed to be present in the fuel of fast neutron reactors were established. In recent years, and in particular in connection with the generation IV initiative, it has been advocated that recycling of americium in critical reactors is not only feasible, but also a recommendable approach. In the present contribution, it is shown, to the contrary, that introduction of americium into reactors with uranium based fuels deteriorates the safety margin of these reactors to a degree that will not allow consumption of the americium sources present in any economically competitive nuclear fuel cycle. Further, it is shown that uranium and thorium free cores with plutonium based fuels may be designed, that features excellent safety characteristics, as long as americium is not present in the feed. Hence, a closed fuel cycle is suggested, that consists of commercial power production in light water reactors, plutonium burning in uranium and thorium free fast neutron critical reactors, and higher actinide consumption in accelerator driven systems with inert matrix fuel. It is argued that such a fuel cycle (being a refinement of the Double Strata fuel cycle proposed by JAERI and further developed by M. Salvatores) provides a minimum cost penalty for implementing P and T under realistic boundary conditions. (author)

  12. Decontaminaion of metals containing plutonium and americium

    International Nuclear Information System (INIS)

    Seitz, M.G.; Gerding, T.J.; Steindler, M.J.

    1979-06-01

    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 10 6 were measured with boro-silicate slag and of 3 x 10 6 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

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

    International Nuclear Information System (INIS)

    Knighton, J.B.; Hagan, P.G.; Navratil, J.D.; Thompson, G.H.

    1981-01-01

    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 600 0 C 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)

  14. Americium migration in basalt and implications to repository risk analysis

    International Nuclear Information System (INIS)

    Rickert, P.G.

    1980-01-01

    Experiments were performed with americium as a minor component in groundwater. Batch adsorption, migration through column, and filtration experiments were performed. It was determined in batch experiments that americium is strongly adsorbed from solution. It was determined with filtration experiments that large percentages of the americium concentrations suspended by the contact solutions in batch experiments and suspended by the infiltrating groundwater in migration experiments were associated with particulate. Filtration was determined to be the primary mode of removal of americium from infiltrating groundwater in a column of granulated basalt (20 to 50 mesh) and an intact core of permeable basalt. Fractionally, 0.46 and 0.22 of the americium component in the infiltrating groundwater was transported through the column and core respectively. In view of these filtration and migration experiment results, the concept of K/sub d/ in the chromatographic sense is meaningless for predicting americium migration in bedrock by groundwater transport at near neutral pH

  15. Procedure for the analysis of americium in complex matrices

    International Nuclear Information System (INIS)

    Knab, D.

    1978-02-01

    A radioanalytical procedure for the analysis of americium in complex matrices has been developed. Clean separations of americium can be obtained from up to 100 g of sample ash, regardless of the starting material. The ability to analyze large masses of material provides the increased sensitivity necessary to detect americium in many environmental samples. The procedure adequately decontaminates from rare earth elements and natural radioactive nuclides that interfere with the alpha spectrometric measurements

  16. Recovery and purification of americium from molten salt extraction residues

    International Nuclear Information System (INIS)

    Navratil, J.D.; Martella, L.L.; Thompson, G.H.

    1980-01-01

    Americium recovery and purification development at Rocky Flats involves the testing of a combined anion exchange - bidentate organophosphorus liquid - liquid extraction or extraction chromatography process for separating americium from molten salt extraction residues. Laboratory-scale and preliminary pilot-plant results have shown that americium can be effectively recovered and purified from impurity elements such as aluminum, calcium, magnesium, plutonium, potassium, sodium, and zinc. The purified americium oxide product from the liquid - liquid extraction process contained greater than 95% AmO 2 with less than 1% of any individual impurity element

  17. Investigation of americium-241 metal alloys for target applications

    International Nuclear Information System (INIS)

    Conner, W.V.; Rockwell International Corp., Golden, CO

    1982-01-01

    Several 241 Am metal alloys have been investigated for possible use in the Lawrence Livermore National Laboratory Radiochemical Diagnostic Tracer Program. Several properties were desired for an alloy to be useful for tracer program applications. A suitable alloy would have a fairly high density, be ductile, homogeneous and easy to prepare. Alloys investigated have included uranium-americium, aluminium-americium, and cerium-americium. Uranium-americium alloys with the desired properties proved to be difficult to prepare, and work with this alloy was discontinued. Aluminium-americium alloys were much easier to prepare, but the alloy consisted of an aluminium-americium intermetallic compound (AmAl 4 ) in an aluminum matrix. This alloy could be cast and formed into shapes, but the low density of aluminum, and other problems, made the alloy unsuitable for the intended application. Americium metal was found to have a high solid solubility in cerium and alloys prepared from these two elements exhibited all of the properties desired for the tracer program application. Cerium-americium alloys containing up to 34 wt% americium have been prepared using both co-melting and co-reduction techniques. The latter technique involves co-reduction of cerium tetrafluoride and americium tetrafluoride with calcium metal in a sealed reduction vessel. Casting techniques have been developed for preparing up to eight 2.2 cm (0.87 in) diameter disks in a single casting, and cerium-americium metal alloy disks containing from 10 to 25 wt% 241 Am have been prepared using these techniques. (orig.)

  18. Investigation of factors affecting the quality of americium electroplating.

    Science.gov (United States)

    Trdin, M; Benedik, L; Samardžija, Z; Pihlar, B

    2012-09-01

    Four different electrolyte solutions were used in the electrodeposition of americium and their influences on the quality of the thin layer of deposited americium isotopes in combination with three different cathode disc materials were investigated. The relations between alpha spectral resolution and disc surface properties were established. Copyright © 2012 Elsevier Ltd. All rights reserved.

  19. Americium/curium bushing melter drain tests

    International Nuclear Information System (INIS)

    Smith, M.E.; Hardy, B.J.; Smith, M.E.

    1997-01-01

    Americium and curium were produced in the past at the Savannah River Site (SRS) for research, medical, and radiological applications. They have been stored in a nitric acid solution in an SRS reprocessing facility for a number of years. Vitrification of the americium/curium (Am/Cm) solution will allow the material to be safely stored or transported to the DOE Oak Ridge Reservation. Oak Ridge is responsible for marketing radionuclides for research and medical applications. The bushing melter technology being used in the Am/Cm vitrification research work is also under consideration for the stabilization of other actinides such as neptunium and plutonium. A series of melter drain tests were conducted at the Savannah River Technology Center to determine the relationship between the drain tube assembly operating variables and the resulting pour initiation times, glass flowrates, drain tube temperatures, and stop pour times. Performance criteria such as ability to start and stop pours in a controlled manner were also evaluated. The tests were also intended to provide support of oil modeling of drain tube performance predictions and thermal modeling of the drain tube and drain tube heater assembly. These drain tests were instrumental in the design of subsequent melter drain tube and drain tube heaters for the Am/Cm bushing melter, and therefore in the success of the Am/Cm vitrification and plutonium immobilization programs

  20. Investigation of factors affecting the quality of americium electroplating

    International Nuclear Information System (INIS)

    Trdin, M.; Benedik, L.; Samardžija, Z.; Pihlar, B.

    2012-01-01

    Four different electrolyte solutions were used in the electrodeposition of americium and their influences on the quality of the thin layer of deposited americium isotopes in combination with three different cathode disc materials were investigated. The relations between alpha spectral resolution and disc surface properties were established. - Highlights: ► Compared alpha spectra of americium radioisotopes obtained by electrodeposition. ► Various cathode materials and electrolyte solutions were used. ► Homogeneity and peak area resolution were investigated. ► Electron microscope images show surface structure of electrodeposited material.

  1. Measurement of plutonium and americium in molten salt residues

    International Nuclear Information System (INIS)

    Haas, F.X.; Lawless, J.L.; Herren, W.E.; Hughes, M.E.

    1979-01-01

    The measurement of plutonium and americium in molten salt residues using a segmented gamma-ray scanning device is described. This system was calibrated using artificially fabricated as well as process generated samples. All samples were calorimetered and the americium to plutonium content of the samples determined by gamma-ray spectroscopy. For the nine samples calorimetered thus far, no significant biases are present in the comparison of the segmented gamma-ray assay and the calorimetric assay. Estimated errors are of the order of 10 percent and is dependent on the americium to plutonium ratio determination

  2. Behavior of americium in aqueous carbonate systems

    Energy Technology Data Exchange (ETDEWEB)

    Silva, R.J.

    1983-11-01

    The solubilities of crystalline Am(OH)/sub 3/ and AmOHCO/sub 3/ were measured at 25/sup 0/C in aqueous solutions of 0.1 M NaClO/sub 4/ by determination of the solution concentrations of Am. Prior to use in the measurements, the solid materials were characterized by their x-ray powder diffraction patterns. The solubility product quotients were calculated from the experimental data. The hydrolysis quotients of Am/sup 3 +/ were also estimated from the hydroxide solubility data. Using the thermodynamic data derived from these experiments and the recently reported formation constants for the Am/sup 3 +/ carbonate complexes, the solid phases and concentrations of solution species of americium in several aqueous carbonate systems were calculated using the computer code MINEQL. 20 references, 1 figure, 1 table.

  3. 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

  4. Uptake of americium-241 by algae and bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Geisy, J P; Paine, D

    1978-01-01

    Algae and bacteria are important factors in the transport and mobilization of elements in the biosphere. These factors may be involved in trophic biomagnification, resulting in a potential human hazard or environmental degradation. Although americium, one of the most toxic elements known, is not required for plant growth, it may be concentrated by algae and bacteria. Therefore, the availability of americium-241 to algae and bacteria was studied to determine their role in the ultimate fate of this element released into the environment. Both algae and bacteria concentrated americium-241 to a high degree, making them important parts of the biomagnification process. The ability to concentrate americium-241 makes algae and bacteria potentially significant factors in cycling this element in the water column. (4 graphs, numerous references, 3 tables)

  5. PROCESS FOR SEPARATING AMERICIUM AND CURIUM FROM RARE EARTH ELEMENTS

    Science.gov (United States)

    Baybarz, R.D.; Lloyd, M.H.

    1963-02-26

    This invention relates to methods of separating americium and curium values from rare earth values. In accordance with the invention americium, curium, and rare earth values are sorbed on an anion exchange resin. A major portion of the rare earth values are selectively stripped from the resin with a concentrated aqueous solution of lithium chloride, and americium, curium, and a minor portion of rare earth values are then stripped from the resin with a dilute aqueous solution of lithium chloride. The americium and curium values are further purified by increasing the concentration of lithium chloride in the solution to at least 8 molar and selectively extracting rare earth values from the resulting solution with a monoalkylphosphoric acid. (AEC)

  6. Sorption of americium and neptunium by deep-sea sediments

    International Nuclear Information System (INIS)

    Higgo, J.J.W.; Rees, L.V.C.; Cronan, D.S.

    1983-01-01

    The sorption and desorption of americium and neptunium by a wide range of deep-sea sediments from natural sea water at 4 0 C has been studied using a carefully controlled batch technique. All the sediments studied should form an excellent barrier to the migration of americium since distribution coefficients were uniformly greater than 10 5 and the sorption-desorption reaction may not be reversible. The sorption of neptunium was reversible and, except for one red clay, the distribution coefficients were greater than 10 3 for all the sediments investigated. Nevertheless the migration of neptunium should also be effectively retarded by most deep-sea sediments even under relatively oxidizing conditions. The neptunium in solution remained in the V oxidation state throughout the experiments. Under the experimental conditions used colloidal americium was trapped by the sediment and solubility did not seem to be the controlling factor in the desorption of americium. (Auth.)

  7. Americium/Curium Disposition Life Cycle Planning Study

    International Nuclear Information System (INIS)

    Jackson, W.N.; Krupa, J.; Stutts, P.; Nester, S.; Raimesch, R.

    1998-01-01

    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)

  8. Comparative behavior of americium and plutonium in wastewater

    International Nuclear Information System (INIS)

    Tsvetaeva, N.E.; Filin, V.M.; Ragimov, T.K.; Rudaya, L.Y.; Shapiro, K.Y.; Shcherbakov, B.Y.

    1986-01-01

    This paper studies the behavior of trace americium and plutoniumin wastewater fed into purification systems. Activities of the elements were determined on a semiconductive alpha-ray spectrometer. the distributio nonuniformity, or heterogeneity, of americium and plutonium per unit volume of wastewater was determined quantitatively before and after passage through filter papers. The two elements were found to be in a colloidal or pseudocolloidal state in the original wastewater sample at pH 6. On acidifying the wastewater from pH 4 to 1 M nitric acid the americium passed quantitatively into the water phase but the most plutonium remained in the colloidal or pseudocolloidal state. the plutonium also passed quantitatively into the water phase in wastewater at a 1 M nitric acid acidity but only after a prolonged (12-day) hold. A knowledge of the heterogeneity of plutonium and americium in wastewaters made it possible to quickly distinguish their state, i.e., colloidal, pseudocolloidal, or in true solution

  9. 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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Gardner, Kyle Shelton [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); 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)

    2016-09-28

    These are a set of slides intended for an information session as part of recruiting activities at Brigham Young University. It gives an overview of aqueous chloride operations, specifically on plutonium and americium purification/recovery. This presentation details the steps taken perform these processes, from plutonium size reduction, dissolution, solvent extraction, oxalate precipitation, to calcination. For americium recovery, it details the CLEAR (chloride extraction and actinide recovery) Line, oxalate precipitation and calcination.

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

    International Nuclear Information System (INIS)

    Fife, K.W.; West, M.H.

    1987-05-01

    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

  12. 1976 Hanford americium-exposure incident: external decontamination procedures

    International Nuclear Information System (INIS)

    Jech, J.J.; Berry, J.R.; Breitenstein, B.D.

    1982-01-01

    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

  13. Preparation of americium metal of high purity and determination of the heat of formation of the hydrated trivalent americium ion

    International Nuclear Information System (INIS)

    Spirlet, J.C.

    1975-10-01

    In order to redetermine some physical and chemical properties of americium metal, several grams of Am-241 have been prepared by two independent methods: lanthanum reduction of the oxide and thermal dissociation of the intermetallic compound Pt 5 Am. After its separation from excess lanthanum or alloy constituent by evaporation, americium metal was further purified by sublimation at 1100 deg C and 10 -6 Torr. Irrespective of the method of preparation, the americium samples displayed the same d.h.c.p. crystal structure. As determined by vacuum hot extraction, the oxygen, nitrogen and hydrogen contents are equal to or smaller than 250, 50 and 20 ppm, respectively. The heats of solution of americium metal (d.c.h.p. structure) in aqueous hydrochloric acid solutions have been measured at 298.15+-0.05K. The standard enthalpy of formation of Am 3+ (aq) is obtained as -616.7+-1.2 kJ mol -1 [fr

  14. 49 CFR 236.563 - Delay time.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Delay time. 236.563 Section 236.563 Transportation... Cab Signal Systems Rules and Instructions; Locomotives § 236.563 Delay time. Delay time of automatic... requirements of § 236.24 shall take into consideration the delay time. ...

  15. 49 CFR 236.588 - Periodic test.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Periodic test. 236.588 Section 236.588..., Train Control and Cab Signal Systems Inspection and Tests; Locomotive § 236.588 Periodic test. Except as provided in § 236.586, periodic test of the automatic train stop, train control, or cab signal apparatus...

  16. Citric complexes, neodymium citrate and americium citrate

    International Nuclear Information System (INIS)

    Bouhlassa, Saidati.

    1981-06-01

    The behaviour of neodymium and americium has been studied in citric aqueous medium by two methods: solvent extraction of elements at tracer scale as chelates and by potentiometry. So range of pH and concentrations of elements and citric acid never reached before have been explored: 10 -7 -1 M, 10 -10 -3 , Csub(H3 Cit) -1 M, 1 2 O; AmCit, xH 2 O; NdCit 2 Co(NH 3 ) 6 , 8H 2 O; AmCit 2 Co(NH 3 ) 6 , xH 2 O and Nd 3 (OH) 4 (Cit) 4 NH 4 (Co(NH 3 ) 6 ) 2 , 18H 2 O. Their spectroscopic and crystallographic characteristics have been listed and studied. The nephelauxetic effect has been estimated from citric complexes as well as from citrates of these elements. The structure of the complexes in solution has been discussed on the basis of analysis of hypersensitive transition in different complexes [fr

  17. Biosorption of americium-241 by Candida sp

    International Nuclear Information System (INIS)

    Luo Shunzhong; Zhang Taiming; Liu Ning; Yang Yuanyou; Jin Jiannan; Liao Jiali

    2003-01-01

    As an important radioisotope in nuclear industry and other fields, americium-241 is one of the most serious contamination concerns duo to its high toxicity and long half-life. In this experiment, the biosorption of 241 Am from solution by Candida sp., and the effects of various experimental conditions on the adsorption were investigated. The preliminary results showed that the adsorption of 241 Am by Candida sp. was efficient. 241 Am could be removed by Candida sp. of 0.82 g/L (dry weight) from 241 Am solutions of 5.6-111 MBq/L (44.3-877.2 μg/L)(C 0 ), with maximum adsorption rate (R) of 98% and maximum adsorption capacities (W) of 63.5 MBq/g biomass (dry weight) (501.8 μg/g). The biosorption equilibrium was achieved within 4 hour and the optimum pH was pH = 2. No significant differences on 241 Am adsorption were observed at 10 C-45 C, or in solutions containing Au 3+ or Ag + , even 1500 times or 4500 times above the 241 Am concentration, respectively. The relationship between concentrations and adsorption capacities of 241 Am indicated the biosorption process should be described by a Langmuir adsorption isotherm. (orig.)

  18. Americium-curium vitrification process development

    International Nuclear Information System (INIS)

    Fellinger, A.P.; Baich, M.A.; Hardy, B.J

    1999-01-01

    The successful demonstration of sequentially drying, calcining and vitrifying an oxalate slurry in the Drain Tube Test Stand (DTTS) vessel provided the process basis for testing on a larger scale in a cylindrical induction heated melter. A single processing issue, that of batch volume expansion, was encountered during the initial stage of testing. The increase in batch volume centered on a sintered frit cap and high temperature bubble formation. The formation of a sintered frit cap expansion was eliminated with the use of cullet. Volume expansions due to high temperature bubble formation (oxygen liberation from cerium reduction) were mitigated in the DTTS melter vessel through a vessel temperature profile that effectively separated the softening point of the glass cullet and the evolving oxygen from cerium reduction. An increased processing temperature of 1,470 C and a two hour hold time to find any remaining bubbles successfully reduced bubbles in the poured glass to an acceptable level. The success of the preliminary process demonstrations provided a workable process basis that was directly applicable to the newly installed Cylindrical Induction Melter (CIM) system, making the batch flowsheet the preferred option for vitrification of the americium-curium surrogate feed stream

  19. Supported extractant membranes for americium and plutonium recovery

    International Nuclear Information System (INIS)

    Muscatello, A.C.; Navratil, J.D.; Killion, M.E.; Price, M.Y.

    1987-01-01

    Solid supported liquid membranes(SLM) are useful in transferring and concentrating americium and plutonium from nitrate solutions. Specifically, DHDECMP(dihexyl-N,N-diethylcarbamoylmethylphosphonate) supported on Accurel or Celgard polypropylene hollow fibers assembled in modular form transfers >95% of the americium and >70% of the plutonium from high nitrate (6.9 M), low acid (0.1 M) feeds into 0.25 M oxalic acid stripping solution. Membranes supporting TBP (tri-n-butylphosphate) also transfer these metal ions. Maximum permeabilities were observed to be 1 x 10 -3 cm sec -1 , similar to the values for other systems. The feed:strip volume ratio shows an inverse relationship to the fraction of metal ion transferred. Cation exchangers may be used to concentrate americium from the strip solution

  20. Synergistic extraction behaviour of americium from simulated acidic waste solutions

    International Nuclear Information System (INIS)

    Pathak, P.N.; Veeraraghavan, R.; Mohapatra, P.K.; Manchanda, V.K.

    1998-01-01

    The extraction behaviour of americium has been investigated with mixtures of 3-phenyl-4-benzoyl-5-isoxazolone (PBI) and oxodonors viz. tri-n-butyl phosphate (TBP), tri-n-octyl phosphine oxide (TOPO) and di-n-butyl octanamide (DBOA) using dodecane as the diluent from 1-6 M HNO 3 media. It is observed that D Am remains unaltered with PBI concentration (in the range 0.06-0.1 M) at 1.47 M TBP in the entire range of HNO 3 concentration. PBI and TBP in combination appears more promising compared to other synergistic systems. The possibility of using this mixture for americium removal from high level liquid waste solution has been explored. Extraction studies indicated that prior removal of uranium by 20% TBP in dodecane is helpful in the quantitative recovery of americium in three contacts. Effect of lanthanides on D Am is found to be marginal. (orig.)

  1. Uptake of americium-241 by algae and bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Giesy, Jr, J P; Paine, D [Savannah River Ecology Lab., Aiken, S.C. (USA)

    1978-01-01

    The uptake of americium by three algae, Scenedesmus obliguus, 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 /sup 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.

  2. The ingestion of plutonium and americium by range cattle

    International Nuclear Information System (INIS)

    Blincoe, C.; Bohman, V.R.; Smith, D.D.

    1981-01-01

    The intake of plutonium and americium in the diet of cattle grazing on plutonium contaminated desert range was determined. Daily feed intake of the grazing animals was also determined so that the amount of nuclides ingested daily could be ascertained. Soil ingested by range cattle constituted the principal and possibly only source of ingested plutonium and americium and resulted in a daily intake of 3600-6600 pCi 238 Pu, 85,000-400,000 pCi 239 Pu, and 11,000-31,000 pCi 241 Am daily. Determining transuranic intake by direct measurement and from the composition and contamination of the diet gave identical results. (author)

  3. Method of isolation of traces of americium by using the +6 oxidation state properties

    International Nuclear Information System (INIS)

    Kwinta, Jean; Michel, Jean-Jacques

    1969-05-01

    The authors present a method to separate traces of americium from a solution containing fission products and actinides. This method comprises the following steps: firstly, the oxidation of americium at the +6 state by ammonium persulfate and carrying over of actinides and III and IV lanthanides by lanthanum fluoride; secondly, the reduction by hydrazine of the oxidized americium and carrying over of the reduced americium by lutetium fluoride; and thirdly, the americium-lutetium separation by selective extractions either with di 2 ethyl hexyl phosphoric acid, or by fractionated elution on an anionic resin column by a mixture of nitric acid and methanol [fr

  4. 49 CFR 236.705 - Bar, locking.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Bar, locking. 236.705 Section 236.705..., MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Definitions § 236.705 Bar, locking. A bar in an interlocking machine to which the locking dogs are attached. ...

  5. 49 CFR 236.516 - Power supply.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Power supply. 236.516 Section 236.516..., Train Control and Cab Signal Systems Standards § 236.516 Power supply. Automatic cab signal, train stop, or train control device hereafter installed shall operate from a separate or isolated power supply...

  6. 36 CFR 2.36 - Gambling.

    Science.gov (United States)

    2010-07-01

    ... 36 Parks, Forests, and Public Property 1 2010-07-01 2010-07-01 false Gambling. 2.36 Section 2.36 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR RESOURCE PROTECTION, PUBLIC USE AND RECREATION § 2.36 Gambling. (a) Gambling in any form, or the operation of gambling...

  7. 8 CFR 236.13 - Ineligible aliens.

    Science.gov (United States)

    2010-01-01

    ... 8 Aliens and Nationality 1 2010-01-01 2010-01-01 false Ineligible aliens. 236.13 Section 236.13 Aliens and Nationality DEPARTMENT OF HOMELAND SECURITY IMMIGRATION REGULATIONS APPREHENSION AND DETENTION OF INADMISSIBLE AND DEPORTABLE ALIENS; REMOVAL OF ALIENS ORDERED REMOVED Family Unity Program § 236...

  8. 49 CFR 236.105 - Electric lock.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Electric lock. 236.105 Section 236.105 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION...: All Systems Inspections and Tests; All Systems § 236.105 Electric lock. Electric lock, except forced...

  9. 42 CFR 438.236 - Practice guidelines.

    Science.gov (United States)

    2010-10-01

    ... 42 Public Health 4 2010-10-01 2010-10-01 false Practice guidelines. 438.236 Section 438.236 Public... Improvement Standards § 438.236 Practice guidelines. (a) Basic rule: The State must ensure, through its...) Adoption of practice guidelines. Each MCO and, when applicable, each PIHP and PAHP adopts practice...

  10. 49 CFR 236.718 - Chart, dog.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Chart, dog. 236.718 Section 236.718 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF... OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Definitions § 236.718 Chart, dog. A...

  11. 49 CFR 236.742 - Dog, locking.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Dog, locking. 236.742 Section 236.742 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION..., MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Definitions § 236.742 Dog...

  12. 49 CFR 236.743 - Dog, swing.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Dog, swing. 236.743 Section 236.743 Transportation... OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Definitions § 236.743 Dog, swing. A locking dog mounted in such a manner that it is free to rotate on a trunnion which is riveted to a locking...

  13. 49 CFR 236.712 - Brake pipe.

    Science.gov (United States)

    2010-10-01

    ... OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Definitions § 236.712 Brake pipe. A pipe running from the engineman's brake valve through the train, used for the transmission of air under... 49 Transportation 4 2010-10-01 2010-10-01 false Brake pipe. 236.712 Section 236.712 Transportation...

  14. 49 CFR 236.384 - Cross protection.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Cross protection. 236.384 Section 236.384 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION... and Tests § 236.384 Cross protection. Cross protection shall be tested at least once every six months...

  15. 24 CFR 236.901 - Audit.

    Science.gov (United States)

    2010-04-01

    ... 24 Housing and Urban Development 2 2010-04-01 2010-04-01 false Audit. 236.901 Section 236.901... AND INTEREST REDUCTION PAYMENT FOR RENTAL PROJECTS Audits § 236.901 Audit. Where a State or local... mortgagor of a mortgage insured or held by the Commissioner under this part, it shall conduct audits in...

  16. 49 CFR 236.587 - Departure test.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Departure test. 236.587 Section 236.587..., Train Control and Cab Signal Systems Inspection and Tests; Locomotive § 236.587 Departure test. (a) The...: (1) Operation over track elements; (2) Operation over test circuit; (3) Use of portable test...

  17. 24 CFR 236.60 - Excess Income.

    Science.gov (United States)

    2010-04-01

    ... 24 Housing and Urban Development 2 2010-04-01 2010-04-01 false Excess Income. 236.60 Section 236... § 236.60 Excess Income. (a) Definition. Excess Income consists of cash collected as rent from the... Rent. The unit-by-unit requirement necessitates that, if a unit has Excess Income, the Excess Income...

  18. 49 CFR 236.717 - Characteristics, operating.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Characteristics, operating. 236.717 Section 236.717 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD... § 236.717 Characteristics, operating. The measure of electrical values at which electrical or electronic...

  19. 49 CFR 236.721 - Circuit, control.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Circuit, control. 236.721 Section 236.721..., MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Definitions § 236.721 Circuit, control. An electrical circuit between a source of electric energy and a device which it operates. ...

  20. 49 CFR 236.777 - Operator, control.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Operator, control. 236.777 Section 236.777..., MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Definitions § 236.777 Operator, control. An employee assigned to operate the control machine of a traffic control system. ...

  1. 49 CFR 236.814 - Station, control.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Station, control. 236.814 Section 236.814..., MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Definitions § 236.814 Station, control. The place where the control machine of a traffic control system is located. ...

  2. 49 CFR 236.771 - Machine, control.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Machine, control. 236.771 Section 236.771..., MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Definitions § 236.771 Machine, control. An assemblage of manually operated devices for controlling the functions of a traffic...

  3. 49 CFR 236.708 - Block.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Block. 236.708 Section 236.708 Transportation... OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Definitions § 236.708 Block. A length of track of defined limits, the use of which by trains is governed by block signals, cab signals, or both. ...

  4. 49 CFR 236.801 - Shoe, latch.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Shoe, latch. 236.801 Section 236.801 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION..., MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Definitions § 236.801...

  5. On the role of different biocomponents of bile and excretions in the elimination of plutonium and americium from the body

    International Nuclear Information System (INIS)

    Shvydko, N.S.

    1986-01-01

    A study was made of the role of biocomponents of bile, urine and feces in the elimination of plutonium and americium from the organism. Plutonium 239 and americium 241 were separated in bile due to higher tropism of plutonium to low molecular weight addends, and of americium, to a protein-containing fraction. The status of plutonium excreted in feces was the same as the physicochemical status of americium. Plutonium 239 and americium 241 eliminated in urine were in a completely ultrafiltered state

  6. Determination of plutonium, americium and curium in the marine environment

    International Nuclear Information System (INIS)

    Grenaut, CLaude; Germain, Pierre; Miramand, Pierre.

    1982-01-01

    The method used in the Laboratory for plutonium, americium and curium determination in marine samples (water, sediments, animals, plants) is presented. It is a modification of a procedure based on adsorption on ion exchange resins developed by other authors. The preliminary preparation of the samples, the radiochemical procedures and electrodeposition are described so as to be used as a practical handbook [fr

  7. Recovery of americium-241 from aged plutonium metal

    International Nuclear Information System (INIS)

    Gray, L.W.; Burney, G.A.; Reilly, T.A.; Wilson, T.W.; McKibben, J.M.

    1980-12-01

    About 5 kg of ingrown 241 Am was recovered from 850 kg of aged plutonium using a process developed specifically for Savannah River Plant application. The aged plutonium metal was first dissolved in sulfamic acid. Sodium nitrite was added to oxidize the plutonium to Pu(IV) and the residual sulfamate ion was oxidized to nitrogen gas and sulfate. The plutonium and americium were separated by one cycle of solvent extraction. The recovered products were subsequently purified by cation exchange chromatography, precipitated as oxalates, and calcined to the oxides. Plutonium processng was routine. Before cation exchange purification, the aqueous americium solution from solvent extraction was concentrated and stripped of nitric acid. More than 98% of the 241 Am was then recovered from the cation exchange column where it was effectively decontaminated from all major impurities except nickel and chromium. This partially purified product solution was concentrated further by evaporation and then denitrated by reaction with formic acid. Individual batches of americium oxalate were then precipitated, filtered, washed, and calcined. About 98.5% of the americium was recovered. The final product purity averaged 98% 241 AmO 2 ; residual impurities were primarily lead and nickel

  8. 1976 Hanford americium exposure incident: overview and perspective

    International Nuclear Information System (INIS)

    Thompson, R.C.

    1982-01-01

    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

  9. Thermodynamic systematics of oxides of americium, curium, and neighboring elements

    International Nuclear Information System (INIS)

    Morss, L.R.

    1984-01-01

    Recently-obtained calorimetric data on the sesquioxides and dioxides of americium and curium are summarized. These data are combined with other properties of the actinide elements to elucidate the stability relationships among these oxides and to predict the behavior of neighboring actinide oxides. 45 references, 4 figures, 5 tables

  10. 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.

  11. 236-Z canyon utilization study

    International Nuclear Information System (INIS)

    Dixon, D.R.

    1977-01-01

    The 236-Z canyon contains equipment for repurification of plutonium and recovery of plutonium from scrap material. To meet production requirements of Fast Flux Test Facility/Clinch River Breeder Reactor oxide with the existing plant, several new pieces of equipment will be needed in the future. More storage space and a better accountability system are needed to support this increased production. The available canyon space needs to be utilized to its fullest in order to accommodate the new equipment. The purpose of this document is to identify the new pieces of equipment, show how they fit into the flowsheet, and locate them in the canyon

  12. Contribution to the study of higher valency states of americium

    International Nuclear Information System (INIS)

    Langlet, Jean.

    1976-01-01

    Study of the chemistry of the higher valencies of americium in aqueous solutions and especially the autoreduction phenomenon. First a purification method of americium solutions is studied by precipitation, solvent extraction and ion exchange chromatography. Studies of higher valency states chemical properties are disturbed by the autoreduction phenomenon changing Am VI and Am V in Am III more stable. Stabilization of higher valency states, characterized by a steady concentration of Am VI in solution, can be done by complexation of Am VI and Am V ions or by a protecting effect of foreign ions. The original medium used has a complexing effect by SO 4 2- ions and a protecting effect by the system S 2 O 8 2- -Ag + consuming H 2 O 2 main reducing agent produced by water radiolysis. These effects are shown by the study of Am VI in acid and basic solutions. A mechanism of the stabilization effect is given [fr

  13. Research program on development of advanced treatment technology for americium-containing aqueous waste in NUCEF

    Energy Technology Data Exchange (ETDEWEB)

    Mineo, Hideaki; Matsumura, Tatsuro; Tsubata, Yasuhiro [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1996-10-01

    A research program was prepared on the development of an advanced treatment process for the americium-containing concentrated aqueous waste in NUCEF, than allows americium recovery for the reuse and the reduction of TRU waste generation. A preliminary analysis was conducted on the separation requirements based on the components estimated for the waste. An R and D strategy was proposed from the view to reduce TRU waste generated in the processing that the highest priority is given on the control of TRU leakage such as americium into the effluent stream after americium recovery and the minimization of salt used in the separation over the decontamination of impurities from americium. The extraction chromatographic method was selected as a candidate technology for americium separation under the principle to use reagents that are functional in acidic conditions such as bidentate extractants of DHEDECMP, CMPO or diamides, considering the larger flexibilities in process modification and possible multi-component separation with compact equipment and the past achievements on the recovery of kg quantities of americium. Major R and D items extracted are screening and evaluation of extractants for americium and plutonium, optimization of separation conditions, selection of denitration method, equipment developments and development of solidification methods of discarded americium after reuse and of various kinds of separation residues. In order to cope these items, four steps of R and D program were proposed, i.e., fundamental experiment in beaker-scale on screening and evaluation of extractants, flowsheet study in bench-scale using simulated and small amount of americium aqueous waste solution to evaluate candidate process, americium recovery test in iron-shielded cell to be installed in NUCEF. It is objected to make recovery of 100g orders of americium used for research on fundamental TRU fuel properties. (J.P.N.)

  14. Separation of Americium from plutonium, Annex 3; Prilog 3: Odvajanje amercijuma od plutonijuma

    Energy Technology Data Exchange (ETDEWEB)

    Cvjeticanin, D; Milic, N; Janicijevic, P; Ratkovic, S [Institute of Nuclear Sciences Boris Kidric, Laboratorija za visoku aktivnost, Vinca, Beograd (Serbia and Montenegro)

    1963-12-15

    Since there was the possibility of working with plutonium milligram quantities, it was possible to study plutonium with contents of americium, which was expected in the about two years old plutonium solutions. Method for separation of the micro quantities of americium and plutonium was needed as well as a multichannel alpha-pulse analyzer. Method for separation of americium from plutonium by thenol trifluoro-acetone (TTA) and anion exchange was adopted.

  15. Transfer of environmental plutonium and americium across the human gut

    International Nuclear Information System (INIS)

    Hunt, G.J.; Leonard, D.R.P.; Lovett, M.B.

    1989-01-01

    Following the ingestion of winkles obtained from a coastal area near Sellafield nuclear reprocessing plant, a group of volunteers provided urine for the next 7 days to be analysed for plutonium and americium. From this, estimates of the intake and gut transfer factors for these isotopes were determined. Preliminary estimates of gut transfer factors from a previous study by the same authors were then re-interpreted and combined with the results from the present study. (UK)

  16. 1976 Hanford americium-exposure incident: decontamination and treatment facility

    International Nuclear Information System (INIS)

    Berry, J.R.; McMurray, B.J.; Jech, J.J.; Breitenstein, B.D.; Quigley, E.J.

    1982-01-01

    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

  17. Ingestion Pathway Transfer Factors for Plutonium and Americium

    International Nuclear Information System (INIS)

    Blanchard, A.

    1999-01-01

    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

  18. Extraction separation of americium and curium. A review

    International Nuclear Information System (INIS)

    Petrzilova, H.

    1976-11-01

    A survey is given of extraction systems suitable for transplutonium element separation and preparation as well as for the practical application of their nuclear properties. Methods are discussed in detail of separating the actinide and the lanthanide fractions from fission and corrosion products and of separating americium from curium. The description is completed with flowsheets showing the separation of transplutonium elements from irradiated targets and waste solutions after spent fuel reprocessing. (L.K.)

  19. Americium-241: the most useful isotope of the actinide elements

    International Nuclear Information System (INIS)

    Navratil, J.D.

    1984-01-01

    Used extensively in nuclear gauges and in many other areas, this man-made element (Atomic Number 95) was first isolated in weighable amounts during World War II. Americium is now a very useful by-product of the nuclear industry and is produced in kilogram amounts by appropriate recovery, separation and purification processes. A review will be presented of its discovery, nuclear and chemical properties, and uses, with emphasis on its production process and separations chemistry

  20. Supercritical Fluid Extraction of Plutonium and Americium from Soil

    International Nuclear Information System (INIS)

    Fox, R.V.; Mincher, B.J.

    2002-01-01

    Supercritical fluid extraction (SFE) of plutonium and americium from soil was successfully demonstrated using supercritical fluid carbon dioxide solvent augmented with organophosphorus and beta-diketone complexants. Spiked Idaho soils were chemically and radiologically characterized, then extracted with supercritical fluid carbon dioxide at 2,900 psi and 65 C containing varying concentrations of tributyl phosphate (TBP) and thenoyltrifluoroacetone (TTA). A single 45 minute SFE with 2.7 mol% TBP and 3.2 mol% TTA provided as much as 88% ± 6.0 extraction of americium and 69% ± 5.0 extraction of plutonium. Use of 5.3 mol% TBP with 6.8 mol% of the more acidic beta-diketone hexafluoroacetylacetone (HFA) provided 95% ± 3.0 extraction of americium and 83% ± 5.0 extraction of plutonium in a single 45 minute SFE at 3,750 psi and 95 C. Sequential chemical extraction techniques were used to chemically characterize soil partitioning of plutonium and americium in pre-SFE soil samples. Sequential chemical extraction techniques demonstrated that spiked plutonium resides primarily (76.6%) in the sesquioxide fraction with minor amounts being absorbed by the oxidizable fraction (10.6%) and residual fractions (12.8%). Post-SFE soils subjected to sequential chemical extraction characterization demonstrated that 97% of the oxidizable, 78% of the sesquioxide and 80% of the residual plutonium could be removed using SFE. These preliminary results show that SFE may be an effective solvent extraction technique for removal of actinide contaminants from soil

  1. Extraction of americium from acid aqueous solutions by diethyl-2-hexyl-pyro-phosphoric acid

    International Nuclear Information System (INIS)

    Guillaume, Bernard

    1971-02-01

    After having outlined the interesting properties of americium and the difficulties of its recovery, the author reports the study of the mechanism of extraction of americium from acid aqueous solutions by using the diethyl-2hexyl-pyro-phosphoric acid. Several aspects are thus discussed: influence of concentration of H 2 DEHPP, influence of the acidity of the aqueous phase, saturation of extracting agent, influence of the diluting agent, complexing of americium, influence of other cations. In a second part, the author reports the application to the recovery of americium from effluents, and discusses the obtained results

  2. Americium Separations from High-Salt Solutions Using Anion Exchange

    International Nuclear Information System (INIS)

    Barr, Mary E.; Jarvinen, Gordon D.; Stark, Peter C.; Chamberlin, Rebecca M.; Bartsch, Richard A.; Zhang, Z.Y.; Zhao, W.

    2001-01-01

    The aging of the US nuclear stockpile presents a number of challenges, including the increasing radioactivity of plutonium residues due to the ingrowth of 241 Am from the β-decay of 241 Pu. We investigated parameters that affect the sorption of Am onto anion-exchange resins from concentrated effluents derived from nitric acid processing of plutonium residues. These postevaporator wastes are nearly saturated solutions of acidic nitrate salts, and americium removal is complicated by physical factors, such as solution viscosity and particulates, as well as by the presence of large quantities of competing metals and acid. Single- and double-contact batch distribution coefficients for americium and neodymium from simple and complex surrogate solutions are presented. Varied parameters include the nitrate salt concentration and composition and the nitric acid concentration. We find that under these extremely concentrated conditions, Am(III) removal efficiencies can surpass 50% per contact. Distribution coefficients for both neodymium and americium are insensitive to solution acidity and appear to be driven primarily by low water activities of the solutions

  3. Gut uptake factors for plutonium, americium and curium

    International Nuclear Information System (INIS)

    Harrison, J.D.

    1982-01-01

    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)

  4. On the structure of thorium and americium adenosine triphosphate complexes

    International Nuclear Information System (INIS)

    Mostapha, Sarah; Berton, Laurence; Boubals, Nathalie; Zorz, Nicole; Charbonnel, Marie-Christine; Fontaine-Vive, Fabien; Den Auwer, Christophe; Solari, Pier Lorenzo

    2014-01-01

    The actinides are chemical poisons and radiological hazards. One challenge to better appraise their toxicity and develop countermeasures in case of exposure of living organisms is to better assess pathways of contamination. Because of the high chemical affinity of those actinide elements for phosphate groups and the ubiquity of such chemical functions in biochemistry, nucleotides and in particular adenosine triphosphate nucleotide (ATP) may be considered critical target building blocks for actinides. Combinations of spectroscopic techniques (Fourier transformed Infra Red [FTIR], Electro-spray Ionization Mass Spectrometry [ESI-MS], and Extended X-ray Absorption Fine Structure [EXAFS]) with quantum chemical calculations have been implemented in order to assess the actinides coordination arrangement with ATP. We describe and compare herein the interaction of ATP with thorium and americium; thorium(IV) as a representative of actinide(IV) like plutonium(IV) and americium(III) as a representative of all heavier actinides. In the case of thorium, an insoluble complex is readily formed. In the case of americium, a behavior identical to that described previously for lutetium has been observed with insoluble and soluble complexes. The comparative study of ATP complexation with Th(IV) and Am(III) shows their ability to form insoluble complexes for which a structural model has been proposed by analogy with previously described Lu(III) complexes. (authors)

  5. On the structure of thorium and americium adenosine triphosphate complexes.

    Science.gov (United States)

    Mostapha, Sarah; Fontaine-Vive, Fabien; Berthon, Laurence; Boubals, Nathalie; Zorz, Nicole; Solari, Pier Lorenzo; Charbonnel, Marie Christine; Den Auwer, Christophe

    2014-11-01

    The actinides are chemical poisons and radiological hazards. One challenge to better appraise their toxicity and develop countermeasures in case of exposure of living organisms is to better assess pathways of contamination. Because of the high chemical affinity of those actinide elements for phosphate groups and the ubiquity of such chemical functions in biochemistry, nucleotides and in particular adenosine triphosphate nucleotide (ATP) may be considered critical target building blocks for actinides. Combinations of spectroscopic techniques (Fourier transformed Infra Red [FTIR], Electrospray Ionization Mass Spectrometry [ESI-MS], and Extended X-ray Absorption Fine Structure [EXAFS]) with quantum chemical calculations have been implemented in order to assess the actinides coordination arrangement with ATP. We describe and compare herein the interaction of ATP with thorium and americium; thorium(IV) as a representative of actinide(IV) like plutonium(IV) and americium(III) as a representative of all heavier actinides. In the case of thorium, an insoluble complex is readily formed. In the case of americium, a behavior identical to that described previously for lutetium has been observed with insoluble and soluble complexes. The comparative study of ATP complexation with Th(IV) and Am(III) shows their ability to form insoluble complexes for which a structural model has been proposed by analogy with previously described Lu(III) complexes.

  6. Americium-241 and -243 as an ion-engine propellant

    International Nuclear Information System (INIS)

    Schachter, M.M.

    1994-01-01

    Commercially available americium-241 and -243 can be obtained as the mixture of the two isotopes in 100-gram quantities--a product of reprocessing spent nuclear powerplant fuel elements along with plutonium. The half-lives of the isotopes are 450 years for the -241 and 8,000 years for the -243 (the plutonium half-life isotope so obtained is 24,000 years). Americium rolled out in thin foil sheets emits alpha-rays (helium-4 ions) and beta-rays--2 valence electrons for each helium ion. Electrons are also considered as ions. As a foil, the americium radiates only a minimal amount of gamma-rays via the Curie effect. With appropriately designed permanent magnet rings insulated with Wood's alloy, the + and - ions can be accelerated from their already 5.5 million electron-Volts to billion and even trillions of electron-Volts by electronic control grids powered by the magnetohydrodynamic effect of electrons and helium ions streaming at the post-rocket nozzle of the ion engine. Protocol for the estimated thrust of this ion rocket engine is more than ten kilograms continuously sustainable for several thousand years

  7. Americium-241 radioisotope thermoelectric generator development for space applications

    International Nuclear Information System (INIS)

    Ambrosi, Richard; Williams, Hugo; Samara-Ratna, Piyal

    2013-01-01

    Space nuclear power systems are under development in the UK in collaboration with European partners as part of a European Space Agency (ESA) programme. Radioisotope thermoelectric generators (RTG) are an important element of this new capability in Europe. RTG systems being developed in Europe are targeting the 10 W electric to 50 W electric power generation range adopting a modular scalable approach to the design. Radiogenic decay heat from radioisotopes can be converted to electrical power by using appropriate semiconductor based thermoelectric materials. The plan for Europe is to develop radioisotope space nuclear power systems based on both thermoelectric and Stirling power conversion systems. Although primarily focused on delivering up to 50 W of electrical power, the European radioisotope thermoelectric system development programme is targeting americium-241 as a fuel source and is maximizing the use of commercially available thermoelectric manufacturing processes in order to accelerate the development of power conversion systems. The use of americium provides an economic solution at high isotopic purity and is product of a separation process from stored plutonium produced during the reprocessing of civil nuclear fuel. A laboratory prototype that uses electrical heating as a substitute for the radioisotope was developed to validate the designs. This prototype has now been tested. This paper outlines the requirements for a European americium-241 fuelled RTG, describes the most recent updates in system design and provides further insight into recent laboratory prototype test campaigns. (author)

  8. Americium-241 radioisotope thermoelectric generator development for space applications

    Energy Technology Data Exchange (ETDEWEB)

    Ambrosi, Richard; Williams, Hugo; Samara-Ratna, Piyal, E-mail: rma8@le.ac.uk [University of Leicester, (United Kingdom); and others

    2013-07-01

    Space nuclear power systems are under development in the UK in collaboration with European partners as part of a European Space Agency (ESA) programme. Radioisotope thermoelectric generators (RTG) are an important element of this new capability in Europe. RTG systems being developed in Europe are targeting the 10 W electric to 50 W electric power generation range adopting a modular scalable approach to the design. Radiogenic decay heat from radioisotopes can be converted to electrical power by using appropriate semiconductor based thermoelectric materials. The plan for Europe is to develop radioisotope space nuclear power systems based on both thermoelectric and Stirling power conversion systems. Although primarily focused on delivering up to 50 W of electrical power, the European radioisotope thermoelectric system development programme is targeting americium-241 as a fuel source and is maximizing the use of commercially available thermoelectric manufacturing processes in order to accelerate the development of power conversion systems. The use of americium provides an economic solution at high isotopic purity and is product of a separation process from stored plutonium produced during the reprocessing of civil nuclear fuel. A laboratory prototype that uses electrical heating as a substitute for the radioisotope was developed to validate the designs. This prototype has now been tested. This paper outlines the requirements for a European americium-241 fuelled RTG, describes the most recent updates in system design and provides further insight into recent laboratory prototype test campaigns. (author)

  9. 49 CFR 236.765 - Locking, mechanical.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Locking, mechanical. 236.765 Section 236.765 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION... Locking, mechanical. An arrangement of locking bars, dogs, tappets, cross locking and other apparatus by...

  10. 49 CFR 236.776 - Movement, trailing.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Movement, trailing. 236.776 Section 236.776 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION... Movement, trailing. The movement of a train over the points of a switch which face in the direction in...

  11. 49 CFR 236.774 - Movement, facing.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Movement, facing. 236.774 Section 236.774 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION... Movement, facing. The movement of a train over the points of a switch which face in a direction opposite to...

  12. 49 CFR 236.702 - Arm, semaphore.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Arm, semaphore. 236.702 Section 236.702 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION..., semaphore. The part of a semaphore signal displaying an aspect. It consists of a blade fastened to a...

  13. 49 CFR 236.707 - Blade, semaphore.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Blade, semaphore. 236.707 Section 236.707 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION... Blade, semaphore. The extended part of a semaphore arm which shows the position of the arm. ...

  14. 48 CFR 552.236-80 - Heat.

    Science.gov (United States)

    2010-10-01

    ... 48 Federal Acquisition Regulations System 4 2010-10-01 2010-10-01 false Heat. 552.236-80 Section... SOLICITATION PROVISIONS AND CONTRACT CLAUSES Text of Provisions and Clauses 552.236-80 Heat. As prescribed in 536.570-11, insert the following clause: Heat (APR 1984) Unless otherwise specified or unless already...

  15. 49 CFR 236.761 - Locking, electric.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Locking, electric. 236.761 Section 236.761 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION... Locking, electric. The combination of one or more electric locks and controlling circuits by means of...

  16. 49 CFR 236.757 - Lock, electric.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Lock, electric. 236.757 Section 236.757... Lock, electric. A device to prevent or restrict the movement of a lever, a switch or a movable bridge, unless the locking member is withdrawn by an electrical device, such as an electromagnet, solenoid or...

  17. 28 CFR 2.36 - Rescission guidelines.

    Science.gov (United States)

    2010-07-01

    ... 28 Judicial Administration 1 2010-07-01 2010-07-01 false Rescission guidelines. 2.36 Section 2.36... guidelines. (a) The following guidelines shall apply to the sanctioning of disciplinary infractions or new... such period of confinement has resulted from initial parole to a detainer). These guidelines specify...

  18. 49 CFR 236.787 - Protection, cross.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Protection, cross. 236.787 Section 236.787 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION... Protection, cross. An arrangement to prevent the improper operation of a signal, switch, movable-point frog...

  19. 49 CFR 236.768 - Locking, time.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Locking, time. 236.768 Section 236.768... Locking, time. A method of locking, either mechanical or electrical, which, after a signal has been caused to display an aspect to proceed, prevents, until after the expiration of a predetermined time...

  20. 49 CFR 236.790 - Release, time.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Release, time. 236.790 Section 236.790... Release, time. A device used to prevent the operation of an operative unit until after the expiration of a predetermined time interval after the device has been actuated. ...

  1. 15 CFR 23.6 - Definitions.

    Science.gov (United States)

    2010-01-01

    ... 15 Commerce and Foreign Trade 1 2010-01-01 2010-01-01 false Definitions. 23.6 Section 23.6 Commerce and Foreign Trade Office of the Secretary of Commerce USE OF PENALTY MAIL IN THE LOCATION AND... entities outside the Office of the Secretary charged with carrying out specified substantive functions (i.e...

  2. 49 CFR 236.791 - Release, value.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Release, value. 236.791 Section 236.791 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION... Release, value. The electrical value at which the movable member of an electromagnetic device will move to...

  3. 8 CFR 236.14 - Filing.

    Science.gov (United States)

    2010-01-01

    ... 8 Aliens and Nationality 1 2010-01-01 2010-01-01 false Filing. 236.14 Section 236.14 Aliens and Nationality DEPARTMENT OF HOMELAND SECURITY IMMIGRATION REGULATIONS APPREHENSION AND DETENTION OF INADMISSIBLE... initial denial, to allow the alien the opportunity to file a new Form I-817 application in order to...

  4. 49 CFR 236.806 - Signal, home.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Signal, home. 236.806 Section 236.806 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION... Signal, home. A roadway signal at the entrance to a route or block to govern trains in entering and using...

  5. 49 CFR 236.804 - Signal, block.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Signal, block. 236.804 Section 236.804 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION... Signal, block. A roadway signal operated either automatically or manually at the entrance to a block. ...

  6. 48 CFR 53.236-1 - Construction.

    Science.gov (United States)

    2010-10-01

    ... 48 Federal Acquisition Regulations System 2 2010-10-01 2010-10-01 false Construction. 53.236-1... AND FORMS FORMS Prescription of Forms 53.236-1 Construction. The following forms are prescribed, as stated below, for use in contracting for construction, alteration, or repair, or dismantling, demolition...

  7. 48 CFR 552.236-72 - Specialist.

    Science.gov (United States)

    2010-10-01

    ... 48 Federal Acquisition Regulations System 4 2010-10-01 2010-10-01 false Specialist. 552.236-72... FORMS SOLICITATION PROVISIONS AND CONTRACT CLAUSES Text of Provisions and Clauses 552.236-72 Specialist. As prescribed in 536.570-3, insert the following clause: Specialist (APR 1984) The term “Specialist...

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

    International Nuclear Information System (INIS)

    Sehmel, G.A.

    1978-01-01

    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

  9. The transmutation of americium: the Ecrix experiments in Phenix

    International Nuclear Information System (INIS)

    Garnier, J.C.; Schmidt, N.; Croixmarie, Y.; Ottaviani, J.P.; Varaine, F.; Saint Jean, C. de

    1999-01-01

    The first americium transmutation experiment in a specific target in PHENIX will occur with the ECRIX-B and ECRIX-H experiments. Beside material testing, the objective is also to represent a concept of transmutation whose specificity is to enhance the kinetics of transmutation by using a moderated spectrum. The moderator materials will be 11 B 4 C and CaH 2 for ECRIX-B and ECRIXH respectively, the irradiation conditions have been predicted for both the neutronics and thermal. The targets (MgO-AmO X pellets) are manufactured in the ATALANTE laboratory and the design is performed according to the PHENIX operating conditions. (authors)

  10. Robotic sample preparation for radiochemical plutonium and americium analyses

    International Nuclear Information System (INIS)

    Stalnaker, N.; Beugelsdijk, T.; Thurston, A.; Quintana, J.

    1985-01-01

    A Zymate robotic system has been assembled and programmed to prepare samples for plutonium and americium analyses by radioactivity counting. The system performs two procedures: a simple dilution procedure and a TTA (xylene) extraction of plutonium. To perform the procedures, the robotic system executes 11 unit operations such as weighing, pipetting, mixing, etc. Approximately 150 programs, which require 64 kilobytes of memory, control the system. The system is now being tested with high-purity plutonium metal and plutonium oxide samples. Our studies indicate that the system can give results that agree within 5% at the 95% confidence level with determinations performed manually. 1 ref., 1 fig., 1 tab

  11. Effect of 241-americium on bone marrow stroma

    International Nuclear Information System (INIS)

    Heuvel, R. van den

    1990-01-01

    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)

  12. Implications of plutonium and americium recycling on MOX fuel fabrication

    International Nuclear Information System (INIS)

    Renard, A.; Pilate, S.; Maldague, Th.; La Fuente, A.; Evrard, G.

    1995-01-01

    The impact of the multiple recycling of plutonium in power reactors on the radiation dose rates is analyzed for the most critical stage in a MOX fuel fabrication plant. The limitation of the number of Pu recycling in light water reactors would rather stem from reactor core physics features. The case of recovering americium with plutonium is also considered and the necessary additions of shielding are evaluated. A comparison between the recycling of Pu in fast reactors and in light water reactors is presented. (author)

  13. Recovery of americium-241 from aged plutonium metal

    International Nuclear Information System (INIS)

    Gray, L.W.; Burney, G.A.; Reilly, T.A.; Wilson, T.W.; McKibben, J.M.

    1980-01-01

    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

  14. Analysis of americium, plutonium and technetium solubility in groundwater

    International Nuclear Information System (INIS)

    Takeda, Seiji

    1999-08-01

    Safety assessments for geologic disposal of radioactive waste generally use solubilities of radioactive elements as the parameter restricting the dissolution of the elements from a waste matrix. This study evaluated americium, plutonium and technetium solubilities under a variety of geochemical conditions using the geochemical model EQ3/6. Thermodynamic data of elements used in the analysis were provided in the JAERI-data base. Chemical properties of both natural groundwater and interstitial water in buffer materials (bentonite and concrete) were investigated to determine the variations in Eh, pH and ligand concentrations (CO 3 2- , F - , PO 4 3- , SO 4 2- , NO 3 - and NH 4 + ). These properties can play an important role in the complexation of radioactive elements. Effect of the groundwater chemical properties on the solubility and formation of chemical species for americium, plutonium and technetium was predicted based on the solubility analyses under a variety of geochemical conditions. The solubility and speciation of the radioactive elements were estimated, taking into account the possible range of chemical compositions determined from the groundwater investigation. (author)

  15. Plutonium and americium extraction studies with bifunctional organophosphorus extractants

    International Nuclear Information System (INIS)

    Navratil, J.D.

    1985-01-01

    Neutral bifunctional organophosphorus extractants, such as octylphenyl-N,N-diisobutylcarbamoylmethylphosphine oxide (CMPO) and dihexyl-N,N-diethylcarbamoylmethylphosphonate (CMP), are under study at the Rocky Flats Plant (RFP) to remove plutonium and americium from the 7M nitric acid waste. These compounds extract trivalent actinides from strong nitric acid, a property which distinguishes them from monofunctional organiphosphorus reagents. Furthermore, the reagents extract hydroytic plutonium (IV) polymer which is present in the acid waste stream. The compounds extract trivalent actinides with a 3:1 stoichiometry, whereas tetra- and hexavalent actinides extract with a stoichiometry of 2:1. Preliminary studies indicate that the extracted plutonium polymer complex contains one to two molecules of CMP per plutonium ion and the plutonium(IV) maintains a polymeric structure. Recent studies by Horwitz and co-workers conclude that the CMPO and CMP reagents behave as monodentate ligands. At RFP, three techniques are being tested for using CMP and CMPO to remove plutonium and americium from nitric acid waste streams. The different techniques are liquid-liquid extraction, extraction chromatography, and solid-supported liquid membranes. Recent tests of the last two techniques will be briefly described. In all the experiments, CMP was an 84% pure material from Bray Oil Co. and CMPO was 98% pure from M and T Chemicals

  16. Lifetime followup of the 1976 americium accident victim: [Final report

    International Nuclear Information System (INIS)

    Breitenstein, B.D. Jr.; Palmer, H.E.

    1988-05-01

    This report describes the 11 year medical course of Harold R. McCluskey, a Hanford nuclear chemical operator, who, at age 64, was involved in an accident in an americium recovery facility in August 1976. As a result of the accident, he was heavily contaminated with americium (Am-241), sustained a substantial internal deposition of this isotope, and was burned with concentrated nitric acid and injured by flying debris about the face and neck. The immediate and long-term medical care is summarized, including decontamination procedures, chelation therapy, and routine and special clinical laboratories studies. The estimates of the operator's Am-241 deposition, post accident and during the remainder of his life and the special techniques and equipment used to make the estimates, are reported. Post-accident, the total amount of Am-241 excreted in his urine and feces was 41 MBq (1.1 mCi). He died of complications of chronic coronary artery disease on August 17, 1987. 20 refs., 2 figs

  17. Plant uptake of americium, curium, and the chemical analog neodymium

    International Nuclear Information System (INIS)

    Weimer, W.C.; Laul, J.C.; Kutt, J.C.; Bondietti, E.A.

    1977-01-01

    The plant uptake from several bulk soils has been determined for neodymium, a chemical analog to the transuranium elements americium and curium, and several other native rare earth elements as well. These investigations have demonstrated that neodymium, which has very similar chemical properties to amercium and curium and should have a similar environmental behavior, does behave indistinguishably under both laboratory and field conditions. The uptake of the weathered or mobile forms of these elements from soils is expected to be governed primarily by their identical oxidation states and nearly identical ionic radii. This hypothesis is strongly supported by the chondritic (primordial) normalized rare earth element patterns in several plants. In these samples, the entire series of rare earth elements behaves as a smooth function of the REE ionic radii, as is also seen in the contiguous soils. This behavior suggests that the plant uptake of other ions with similar chemical properties (i.e., americium and curium) would also be governed by ionic size and charge

  18. Uptake and recovery of americium and uranium by Anacystis biomass

    International Nuclear Information System (INIS)

    Liu, H.H.; Jiunntzong Wu

    1993-01-01

    The optimum conditions for the uptake of americium and uranium from wastewater solutions by Anacystis nidulans cells, and the recovery of these radionuclides were studied. The optimum pH range for both actinides was in the acidic region between 3.0 and 5.0. In a pH 3.5 solution with an algal biomass of 70 μg/mL, up to 95% of the Am and U were taken up by the cells. However, the uptake levels were lowered considerably when ethylene dinitrilotetraacetic acid (EDTA) or iron or calcium ions were present in the solutions. Most of the radionuclides taken up by the cells could also be desorbed by washing with salt solutions. Of nine salt solutions tested, ammonium carbonate was the most effective. Our experiments using algal biomass to remove radionuclides from wastewater showed that about 92% of americium and 85% of uranium in wastewater could be taken up by algal biomass, from which about 46% of the Am and 82% of the U originally present in the wastewater could be recovered by elution with a salt solution. 17 refs., 7 figs., 2 tabs

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

    International Nuclear Information System (INIS)

    Rudisill, T.S.

    1999-01-01

    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

  20. Rare earth elements during diagenesis of abyssal sediments: analogies with a transuranic element americium

    International Nuclear Information System (INIS)

    Boust, D.

    1987-03-01

    One of the possibilities for the storage of high-level radioactive wastes consists in burying them into abyssal sediments, the sediments being supposed to barrier out radionuclides migration. The objective of the work was to estimate the efficiency of sediment barrier with respect to americium. As there is no americium in abyssal sediments, an indirect approach was used: the behaviour of the rare earth elements, the best natural analogs of americium. They were analysed in a 15 m long core, from the Cap Verde abyssal plateau. The terrigenous phase derived from the African continent was modified by short-term processes (1-1000 years); the intermediate rare earth elements were dissolved. Mineral coatings, enriched in rare earth appeared. After burial, the evolution continued at a much slower rate (10 5 - 10 6 years). The rare elements of the mineral coatings derived from the dissolution of the terrigenous phase and from an additional source, deeper in the sediment column. The fluxes of rare earth elements from sediment to water column were estimated. In suboxic sediments, the dissolved particulate equilibrium was related to redox conditions. The short-term reactivity of americium was studied in laboratory experiments. Simple americium migration models showed that the sediments barrier was totally efficient with respect to americium. In the conditions, neptunium 237 a daughter product of americium 241 could induce fluxes of 10 16 atoms per year per ton of stored waste (10 -8 Ci y-1), during millions years, towards the water column [fr

  1. Modelling of curium and americium behaviour during separation with displacing complexing chromatography

    International Nuclear Information System (INIS)

    Chuveleva, Eh.A.; Kharitonov, O.V.; Firsova, L.A.

    1994-01-01

    Certain heavy rare earths, curium and americium were separated by the method of displacement complexing chromatography using DTPA solutions and solutions containing DTPA and citric acid as eluents. Separation factors of rare earths and curium (americium) were calculated. Imitators for curium and americium separation were suggested: thulium for curium elution using 0.025 mol/l DTPA, holmium-for curium elution using 0.025 mol/l DTPA in the presence of 0.025 mol/l citric acid; terbium can serve as the imitator in both cases. 5 refs., 5 figs

  2. Influence of organic components on plutonium and americium speciation in soils and soil solutions

    International Nuclear Information System (INIS)

    Sokolik, G.A.; Ovsyannikova, S.V.; Kimlenko, I.M.

    2003-01-01

    Group composition of humic substances of organic and mineral soils sampled in the 30-km zone of the Chernobyl accident was analyzed for studying influence of organic components on migration properties of plutonium and americium in soils and soil solutions by the method of gel-chromatography and chemical fractionation. It was ascertained that humus of organic soils binds plutonium and americium stronger than humus of mineral soils. Elevated mobility of americium compared to plutonium one stems from lower ability of the latter to from hard to solve organic and organomineral complexes, as well as from its ability to form anionic complexes in soil solutions [ru

  3. Analytical separation of americium and curium, using high performance liquid chromatography

    International Nuclear Information System (INIS)

    Billon, A.

    1978-01-01

    Americium and curium are separated on a column of cation exchange resin (Aminex) using hydroxyisobutyric acid (α HIBA) as eluent, at a temperature of 80 0 C. Americium and curium were detected in line using their α emission: the separation was performed in a shielded glove box whose setting-up is given. Finally, the time necessary for a separation is comprised between 30 min and 1 hr. The purity of separated fractions was assayed by mass-spectrometry. An application in the determination of isotopic composition of americium and curium in fuels is described

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

    International Nuclear Information System (INIS)

    Cole, T.G.; Higgo, J.J.W.; Cronan, D.S.; Rees, L.V.C.

    1984-07-01

    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 (CaCO 3 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)

  5. Americium/Curium Vitrification Pilot Tests - Part II

    International Nuclear Information System (INIS)

    Marra, J.E.; Baich, M.A.; Fellinger, A.P.; Hardy, B.J.; Herman, D.T.; Jones, T.M.; Miller, C.B.; Miller, D.H.; Snyder, T. K.; Stone, M.E.

    1998-05-01

    Isotopes of americium (Am) and curium (Cm) were produced in the past at the Savannah River Site (SRS) for research, medical, and radiological applications. These highly radioactive and valuable isotopes have been stored in an SRS reprocessing facility for a number of years. Vitrification of this solution will allow the material to be more safely stored until it is transported to the DOE Oak Ridge Reservation for use in research and medical applications. A previous paper described operation results from the Am-Cm Melter 2A pilot system, a full-scale non-radioactive pilot facility. This paper presents the results from continued testing in the Pilot Facility and also describes efforts taken to look at alternative vitrification process operations and flowsheets designed to address the problems observed during melter 2A pilot testing

  6. Elimination of americium-241 after a case of accidental inhalation

    International Nuclear Information System (INIS)

    Edvardsson, K.A.; Lindgren, L.

    1976-01-01

    In handling a 241 Am source one person received an internal contamination of about 140 nCi of americium oxide, which was deposited in the lung region. Elimination of the activity was followed for more than 3 months by external gamma counting and excreta analyses. During the first week after the inhalation about 80% of the total intake was eliminated with an effective half-life of less than 2 days. The remaining activity, deposited in the lung region, was eliminated with an effective half-life of about 17 days. About 15% of the activity eliminated from the lung region from the 10th to the 50th day was eliminated in the faeces. (author)

  7. Pretreatment of americium/curium solutions for vitrification

    International Nuclear Information System (INIS)

    Rudisill, T.S.

    1996-01-01

    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

  8. The biokinetics and radiotoxicology of curium: A comparison with americium

    Energy Technology Data Exchange (ETDEWEB)

    Menetrier, F. [CEA, Fontenay-aux-Roses (France); Taylor, D.M. [School of Chemistry, Cardiff University, Cardiff CF10 3AT (United Kingdom)], E-mail: davtay@btinternet.com; Comte, A. [CEA, Fontenay-aux-Roses (France)

    2008-05-15

    The human and animal data on the biokinetics of {sup 242}Cm and {sup 244}Cm are reviewed and shown to be very similar to those for {sup 241}Am. Liver and skeleton are the main organs of deposition and the retention of curium in the skeleton is very prolonged in all the species examined. Retention of both curium and americium in the liver appears to be species-dependent, being relatively rapidly removed from the liver of rats, and probably humans, but being tenaciously retained in dogs and some other species. The radiotoxicity of curium is also reviewed and it is shown that, as with {sup 241}Am, lung and bone tumour induction are the major hazards from inhaled and systemically deposited {sup 244}Cm. The use of chelating agents for the treatment of accidental contamination of the human body with {sup 242,244}Cm is also discussed.

  9. Determination of the oxygen-metal-ratio of uranium-americium mixed oxides

    International Nuclear Information System (INIS)

    Bartscher, W.

    1982-01-01

    During the dissolution of uranium-americium mixed oxides in phosphoric acid under nitrogen tetravalent uranium is oxidized by tetravalent americium. The obtained hexavalent uranium is determined by constant potential coulometry. The coulombs measured are equivalent to the oxygen in excess of the minimum composition of UO 2 x AmO 1 . 5 . The total uranium content of the sample is determined in a subsequent coulometric titration. The oxygen-metal ratio of the sample can be calculated for a given uranium-americium ratio. An excess of uranium dioxide is necessary in order to suppress the oxidation of water by tetravalent americium. The standard deviation of the method is 0.0017 O/M units. (orig.) [de

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

    International Nuclear Information System (INIS)

    Umbarger, C.J.; Jett, J.H.

    1976-01-01

    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

  11. Kinetics of americium(VI) mass transfer through solid supported liquid membrane with HDEHP

    International Nuclear Information System (INIS)

    Mikheeva, M.N.; Novicoov, P.; Myasoedov, B.F.; Tikhomirov, S.V.

    1994-01-01

    The main regularities of membrane extraction of americium under conditions of different redox potentials in aqueous phases have been studied. The physico-chemical model of the process including steps of americium oxidation in feed solution, extraction by membrane, partial reduction on membrane surface, trans-membrane diffusion and reextraction to strip solution has been developed. The calculation of reduction rate constant on membrane surface has been carried out. (author) 9 refs.; 4 figs.; 3 tabs

  12. In-line measurement of plutonium and americium in mixed solutions

    International Nuclear Information System (INIS)

    Li, T.K.

    1981-01-01

    A solution assay instrument (SAI) has been developed at the Los Alamos National Laboratory and installed in the plutonium purification and americium recovery process area in the Los Alamos Plutonium Processing Facility. The instrument is designed for accurate, timely, and simultaneous nondestructive analysis of plutonium and americium in process solutions that have a wide range of concentrations and Am/Pu ratios. For a 25-mL sample, the assay precision is 5 g/L within a 2000-s count time

  13. Radiation protection data sheets for the use of Americium 241 in unsealed sources

    International Nuclear Information System (INIS)

    Anon.

    1993-01-01

    This radiation protection data sheet is intended for supervisors and staff in the different medical, hospital, pharmaceutical, university and industrial laboratories and departments where Americium 241 is handled, and also for all those involved in risk prevention in this field. It provides essential data on radiation protection measures during the use of Americium 241 in unsealed sources: physical characteristics, risk assessment, administrative procedures, recommendations, regulations and bibliography

  14. The transmutation of americium: the Ecrix experiments in Phenix; Transmutation de l'americium: les experiences ecrix dans Phenix

    Energy Technology Data Exchange (ETDEWEB)

    Garnier, J.C.; Schmidt, N. [CEA Cadarache, Dept. d' Etudes des Combustibles (DEC/SESC), 13 - Saint-Paul-lez-Durance (France); Croixmarie, Y.; Ottaviani, J.P. [CEA Cadarache, Dept. d' Etudes des Combustibles (DEC/SPUA), 13 - Saint-Paul-lez-Durance (France); Varaine, F.; Saint Jean, C. de [CEA Cadarache, Dept. d' Etudes des Reacteurs (DER/SPRC), 13 - Saint-Paul-lez-Durance (France)

    1999-07-01

    The first americium transmutation experiment in a specific target in PHENIX will occur with the ECRIX-B and ECRIX-H experiments. Beside material testing, the objective is also to represent a concept of transmutation whose specificity is to enhance the kinetics of transmutation by using a moderated spectrum. The moderator materials will be {sup 11}B{sub 4}C and CaH{sub 2} for ECRIX-B and ECRIXH respectively, the irradiation conditions have been predicted for both the neutronics and thermal. The targets (MgO-AmO{sub X} pellets) are manufactured in the ATALANTE laboratory and the design is performed according to the PHENIX operating conditions. (authors)

  15. The transmutation of americium: the Ecrix experiments in Phenix; Transmutation de l'americium: les experiences ecrix dans Phenix

    Energy Technology Data Exchange (ETDEWEB)

    Garnier, J C; Schmidt, N [CEA Cadarache, Dept. d' Etudes des Combustibles (DEC/SESC), 13 - Saint-Paul-lez-Durance (France); Croixmarie, Y; Ottaviani, J P [CEA Cadarache, Dept. d' Etudes des Combustibles (DEC/SPUA), 13 - Saint-Paul-lez-Durance (France); Varaine, F; Saint Jean, C de [CEA Cadarache, Dept. d' Etudes des Reacteurs (DER/SPRC), 13 - Saint-Paul-lez-Durance (France)

    1999-07-01

    The first americium transmutation experiment in a specific target in PHENIX will occur with the ECRIX-B and ECRIX-H experiments. Beside material testing, the objective is also to represent a concept of transmutation whose specificity is to enhance the kinetics of transmutation by using a moderated spectrum. The moderator materials will be {sup 11}B{sub 4}C and CaH{sub 2} for ECRIX-B and ECRIXH respectively, the irradiation conditions have been predicted for both the neutronics and thermal. The targets (MgO-AmO{sub X} pellets) are manufactured in the ATALANTE laboratory and the design is performed according to the PHENIX operating conditions. (authors)

  16. Biochemical fractionation and cellular distribution of americium and plutonium in the biomass of freshwater macrophytes

    International Nuclear Information System (INIS)

    Zotina, T.A.; Kalacheva, G.S.; Bolsunovsky, A.Ya.

    2011-01-01

    Accumulation of americium ( 241 Am) and plutonium ( 238,242 Pu) and their distribution in cell compartments and biochemical components of the biomass of freshwater aquatic plants Elodea canadensis, Ceratophyllum demersum and Myrioplyllum spicatum and aquatic moss Fontinalis antipyretica have been investigated in laboratory experiments. Americium and plutonium taken up from water by Elodea canadensis apical shoots were mainly absorbed by structural components of plant cells (90% for 241 Am; 89% for 238 Pu and 82-87% for 242 Pu). About 10-18% of isotope activity was recorded in the cytosol fraction. The major concentration (76-92%) of americium was bound to cell wall cellulose-like polysaccharides of Elodea canadensis, Myriophyllum spicatum, Ceratophyllum demersum and Fontinalis antipyretica, 8-24% of americium activity was registered in the fraction of proteins and carbohydrates, and just a minor concentration (<1%) in the lipid fraction. The distribution of plutonium in the biomass fractions of Elodea was similar to that of americium. Hence, americium and plutonium had the highest affinity to cellulose-like polysaccharides of cell walls of freshwater submerged macrophytes. (author)

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

    International Nuclear Information System (INIS)

    Zotina, T.A.; Kalacheva, G.S.; Bolsunovsky, A.YA.

    2010-01-01

    Accumulation of uranium ( 238 U), americium ( 241 Am) and plutonium ( 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. 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)

  19. 48 CFR 236.604 - Performance evaluation.

    Science.gov (United States)

    2010-10-01

    ... 48 Federal Acquisition Regulations System 3 2010-10-01 2010-10-01 false Performance evaluation... Architect-Engineer Services 236.604 Performance evaluation. (a) Preparation of performance reports. Use DD Form 2631, Performance Evaluation (Architect-Engineer), instead of SF 1421. (2) Prepare a separate...

  20. Resolved resonance parameters for 236Np

    International Nuclear Information System (INIS)

    Morogovskij, G.B.; Bakhanovich, L.A.

    2002-01-01

    Multilevel Breit-Wigner parameters were obtained for fission cross-section representation in the 0.01-33 eV energy region from evaluation of a 236 Np experimental fission cross-section in the resolved resonance region. (author)

  1. Reference: 236 [Arabidopsis Phenome Database[Archive

    Lifescience Database Archive (English)

    Full Text Available 236 http://metadb.riken.jp/db/SciNetS_ria224i/cria224u4ria224u15992545i Dharmasiri...5 Jul Developmental cell Dharmasiri Nihal|Dharmasiri Sunethra|Ehrismann Jasmin S|Estelle Mark|Hobbie Lawrence|J端rgens Gerd|Lechner Esther|Weijers Dolf|Yamada Masashi

  2. 49 CFR 236.809 - Signal, slotted mechanical.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Signal, slotted mechanical. 236.809 Section 236.809 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD... § 236.809 Signal, slotted mechanical. A mechanically operated signal with an electromagnetic device...

  3. 49 CFR 236.52 - Relayed cut-section.

    Science.gov (United States)

    2010-10-01

    ..., MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Rules and Instructions: All Systems Track Circuits § 236.52 Relayed cut-section. Where relayed cut-section is used in... 49 Transportation 4 2010-10-01 2010-10-01 false Relayed cut-section. 236.52 Section 236.52...

  4. 46 CFR 169.236 - Inspection and testing required.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Inspection and testing required. 169.236 Section 169.236... Inspection and Certification Repairs and Alterations § 169.236 Inspection and testing required. (a) The... involving riveting, welding, burning, or other fire-producing actions may be made— (1) Within or on the...

  5. 48 CFR 552.236-77 - Specifications and Drawings

    Science.gov (United States)

    2010-10-01

    ... Drawings 552.236-77 Section 552.236-77 Federal Acquisition Regulations System GENERAL SERVICES....236-77 Specifications and Drawings As prescribed in 536.570-8, insert the following clause: Specifications and Drawings (SEP 1999) The requirements of the clause entitled “Specifications and Drawings for...

  6. 48 CFR 52.236-6 - Superintendence by the Contractor.

    Science.gov (United States)

    2010-10-01

    ... Contractor. 52.236-6 Section 52.236-6 Federal Acquisition Regulations System FEDERAL ACQUISITION REGULATION....236-6 Superintendence by the Contractor. As prescribed in 36.506, insert the following clause: Superintendence by the Contractor (APR 1984) At all times during performance of this contract and until the work...

  7. 48 CFR 852.236-78 - Government supervision.

    Science.gov (United States)

    2010-10-01

    ... 48 Federal Acquisition Regulations System 5 2010-10-01 2010-10-01 false Government supervision. 852.236-78 Section 852.236-78 Federal Acquisition Regulations System DEPARTMENT OF VETERANS AFFAIRS CLAUSES AND FORMS SOLICITATION PROVISIONS AND CONTRACT CLAUSES Texts of Provisions and Clauses 852.236-78 Government supervision. As prescribed in...

  8. 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.

  9. Density of simulated americium/curium melter feed solution

    International Nuclear Information System (INIS)

    Rudisill, T.S.

    1997-01-01

    Vitrification will be used to stabilize an americium/curium (Am/Cm) solution presently stored in F-Canyon for eventual transport to Oak Ridge National Laboratory and use in heavy isotope production programs. Prior to vitrification, a series of in-tank oxalate precipitation and nitric/oxalic 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. Following nitric acid dissolution and oxalate destruction, the solution will be denitrated and evaporated to a dissolved solids concentration of approximately 100 g/l (on an oxide basis). During the Am/Cm vitrification, an airlift will be used to supply the concentrated feed solution to a constant head tank which drains through a filter and an in-line orifice to the melter. Since the delivery system is sensitive to the physical properties of the feed, a simulated solution was prepared and used to measure the density as a function of temperature between 20 to 70 degrees C. The measured density decreased linearly at a rate of 0.0007 g/cm3/degree C from an average value of 1.2326 g/cm 3 at 20 degrees C to an average value of 1.1973g/cm 3 at 70 degrees C

  10. Americium/Curium Melter 2A Pilot Tests

    International Nuclear Information System (INIS)

    Smith, M.E.; Fellinger, A.P.; Jones, T.M.; Miller, C.B.; Miller, D.H.; Snyder, T.K.; Stone, M.E.; Witt, D.C.

    1998-05-01

    Isotopes of americium (Am) and curium (Cm) were produced in the past at the Savannah River Site (SRS) for research, medical, and radiological applications. These highly radioactive and valuable isotopes have been stored in an SRS reprocessing facility for a number of years. Vitrification of this solution will allow the material to be more safely stored until it is transported to the DOE Oak Ridge Reservation for use in research and medical applications. To this end, the Am/Cm Melter 2A pilot system, a full-scale non- radioactive pilot plant of the system to be installed at the reprocessing facility, was designed, constructed and tested. The full- scale pilot system has a frit and aqueous feed delivery system, a dual zone bushing melter, and an off-gas treatment system. The main items which were tested included the dual zone bushing melter, the drain tube with dual heating and cooling zones, glass compositions, and the off-gas system which used for the first time a film cooler/lower melter plenum. Most of the process and equipment were proven to function properly, but several problems were found which will need further work. A system description and a discussion of test results will be given

  11. Americium adsorption on the surface of macrophytic algae

    Energy Technology Data Exchange (ETDEWEB)

    Carvalho, F.P.; Fowler, S.W.

    1985-01-01

    Data are presented on the rates at which americium (Am) deposits upon blade surfaces of three benthic algal species (Ulva rigida, Fucus vesiculosus and Gigartina stellata) following short-term exposures (1-6 h). Am is taken up in direct proportion to the ambient radionuclide concentration in sea water. Uptake by the green alga was 3 to 5 times greater than that for the brown and red species. Experimental evidence indicated that Am accumulation is a passive process and that adsorption takes place mainly on the thin outer organic coating of the seaweed. The Am transport coefficients are quite similar to that previously found for the naturally occurring ..cap alpha..-emitter /sup 210/Po, but are an order of magnitude lower than a plutonium transport coefficient reported in the literature. Release of labelled extracellular products associated with the algal surface coating is considered to be responsible for the rapid loss of Am observed previously in macroalgae and may in fact serve as a mechanism for transferring Am to filter feeding zooplankton. (author).

  12. Americium adsorption on the surface of macrophytic algae

    International Nuclear Information System (INIS)

    Carvalho, F.P.; Fowler, S.W.

    1985-01-01

    Data are presented on the rates at which americium (Am) deposits upon blade surfaces of three benthic algal species (Ulva rigida, Fucus vesiculosus and Gigartina stellata) following short-term exposures (1-6 h). Am is taken up in direct proportion to the ambient radionuclide concentration in sea water. Uptake by the green alga was 3 to 5 times greater than that for the brown and red species. Experimental evidence indicated that Am accumulation is a passive process and that adsorption takes place mainly on the thin outer organic coating of the seaweed. The Am transport coefficients are quite similar to that previously found for the naturally occurring α-emitter 210 Po, but are an order of magnitude lower than a plutonium transport coefficient reported in the literature. Release of labelled extracellular products associated with the algal surface coating is considered to be responsible for the rapid loss of Am observed previously in macroalgae and may in fact serve as a mechanism for transferring Am to filter feeding zooplankton. (author)

  13. Density of simulated americium/curium melter feed solution

    Energy Technology Data Exchange (ETDEWEB)

    Rudisill, T.S.

    1997-09-22

    Vitrification will be used to stabilize an americium/curium (Am/Cm) solution presently stored in F-Canyon for eventual transport to Oak Ridge National Laboratory and use in heavy isotope production programs. Prior to vitrification, a series of in-tank oxalate precipitation and nitric/oxalic 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. Following nitric acid dissolution and oxalate destruction, the solution will be denitrated and evaporated to a dissolved solids concentration of approximately 100 g/l (on an oxide basis). During the Am/Cm vitrification, an airlift will be used to supply the concentrated feed solution to a constant head tank which drains through a filter and an in-line orifice to the melter. Since the delivery system is sensitive to the physical properties of the feed, a simulated solution was prepared and used to measure the density as a function of temperature between 20 to 70{degrees} C. The measured density decreased linearly at a rate of 0.0007 g/cm3/{degree} C from an average value of 1.2326 g/cm{sup 3} at 20{degrees} C to an average value of 1.1973g/cm{sup 3} at 70{degrees} C.

  14. Molecular localisation of americium, technetium and cesium in edible marine animals. Their metabolic behavior and their consequences; Localisation moleculaire de l'americium, du technetium et du cesium chez des animaux marins comestibles leur comportement metabolique et ses consequences

    Energy Technology Data Exchange (ETDEWEB)

    Pieri, J; Goudard, F; Milcent, M C [Laboratoire de Biochimie et Radiochimie, Faculte des Sciences et des Techniques, Nantes Cedex (France)

    1992-07-01

    We show the molecular behavior of americium, technetium and cesium on the chromatographic pattern of each cytosol in the digestive gland of eel and lobster. The contamination by cadmium seems to compete with americium in the fractions of MW 10,000. Cesium shows an ionic behavior. (author)

  15. Environmental impact of a teratogenic actinide: a case study of americium-241

    Energy Technology Data Exchange (ETDEWEB)

    Wang, J.; Yang, J.Y.

    1985-10-16

    Americium-241 is widely used as a radiation source, but it also has some potential risk if taken into the body. Although the radiotoxicity of americium-241 is small compared to other transuranic actinides, its effects on the reproductive system and on development of the placenta are more damaging than the effects of plutonium-239. A previous report based on a worst-case scenario involving a hypothetical fire accident in a contaminated facility indicated that there could have been a significant impact on nearby residents from a unit release of americium-241 via atmospheric dispersion. However, because the facility is located in a rural region where most drinking water supplies are drawn from private wells, it is believed that deposition of americium-241 from the atmosphere might also have impacts via the groundwater pathway by infiltration of rainwater. In this analysis, a three-dimensional analytical mathematical model is used to assess several aspects of americium-241 contamination of groundwater, including radioactive transformation, advection, dispersion, and soil sorption. Simulation results indicate that no significant radiological impacts would occur to the nearby residents via the groundwater pathway. 15 refs., 2 figs., 2 tabs.

  16. The availability of plutonium and americium in Irish Sea sediments for re-dissolution

    International Nuclear Information System (INIS)

    McDonald, P.; Vives i Batlle, J.; Bousher, A.; Whittall, A.; Chambers, N.

    2001-01-01

    The availability of plutonium and americium, for re-dissolution from offshore sediments into Irish Sea water, has been examined. Sediments collected from the mud-patch near the Cumbrian coast were characterized in terms of spatial location, particle size, partitioning of radionuclides with respect to physico-chemical bonds and availability of actinides for release into seawater. Sequential extraction investigations revealed that plutonium was predominantly associated with strongly bound sesquioxide and organic complex fractions. Americium was associated mainly with the organic complex fraction, but a significant fraction was in carbonate form. Sediment/water re-dissolution experiments with and without stirring were compared to simulate the effect of disturbing bed sediment. After 1 week, neither set of re-dissolution data provided significant trends between dissolved activity and time. Stirred systems appeared to release 2.5 times more plutonium and americium into seawater than unstirred systems. Measured 239,240Pu and 241Am distribution coefficients (K d values) were both typically approximately 10 5 l kg -1 . 241Am K d values are an order of magnitude lower than previously reported for the north-eastern Irish Sea, but similar to western Irish Sea values. Overall, the fractions of plutonium and americium available for re-dissolution from bed sediment are very low at <0.1%, with proportionally more plutonium being released than americium. These findings lend further support for the extrapolation of laboratory-derived information to environmental conditions

  17. Environmental impact of a teratogenic actinide: a case study of americium-241

    International Nuclear Information System (INIS)

    Wang, J.; Yang, J.Y.

    1985-01-01

    Americium-241 is widely used as a radiation source, but it also has some potential risk if taken into the body. Although the radiotoxicity of americium-241 is small compared to other transuranic actinides, its effects on the reproductive system and on development of the placenta are more damaging than the effects of plutonium-239. A previous report based on a worst-case scenario involving a hypothetical fire accident in a contaminated facility indicated that there could have been a significant impact on nearby residents from a unit release of americium-241 via atmospheric dispersion. However, because the facility is located in a rural region where most drinking water supplies are drawn from private wells, it is believed that deposition of americium-241 from the atmosphere might also have impacts via the groundwater pathway by infiltration of rainwater. In this analysis, a three-dimensional analytical mathematical model is used to assess several aspects of americium-241 contamination of groundwater, including radioactive transformation, advection, dispersion, and soil sorption. Simulation results indicate that no significant radiological impacts would occur to the nearby residents via the groundwater pathway. 15 refs., 2 figs., 2 tabs

  18. Mobility of plutonium and americium through a shallow aquifer in a semiarid region

    International Nuclear Information System (INIS)

    Penrose, W.R.; Polzer, W.L.; Essington, E.H.; Nelson, D.M.; Orlandini, K.A.

    1990-01-01

    Treated liquid wastes containing traces of plutonium and americium are released into Mortandad Canyon, within the site of Los Alamos National Laboratory, NM. The wastes infiltrate a small aquifer within the canyon. Although laboratory studies have predicted that the movement of actinides in subsurface environments will be limited to less than a few meters, both plutonium and americium are detectable in monitoring wells as far as 3,390 m downgradient from the discharge. Between the first and last monitoring wells (1.8 and 3.4 km from the discharge), plutonium concentrations decreased exponentially from 1,400 to 0.55 mBq/L. Americium concentrations ranged between 94 and 1,240 mBq/L, but did not appear to vary in a systematic way with distance. Investigation of the properties of the mobile actinides indicates that the plutonium and part of the americium are tightly or irreversibly associated with colloidal material between 25 and 450 nm in size. The colloidally bound actinides are removed only gradually from the groundwater. The fraction of the americium not associated with colloids exists in a low molecular weight form (diameter, ≤ 2 nm) and appears to be a stable, anionic complex of unknown composition. The mobile forms of these actinides defeat the forces that normally act to retard their movement through groundwater systems

  19. Molecular localisation of americium, technetium and cesium in edible marine animals. Their metabolic behavior and their consequences

    International Nuclear Information System (INIS)

    Pieri, J.; Goudard, F.; Milcent, M.C.

    1992-01-01

    We show the molecular behavior of americium, technetium and cesium on the chromatographic pattern of each cytosol in the digestive gland of eel and lobster. The contamination by cadmium seems to compete with americium in the fractions of MW 10,000. Cesium shows an ionic behavior. (author)

  20. Organic components and plutonium and americium state in soils and soil solutions

    International Nuclear Information System (INIS)

    Sokolik, G.A.; Ovsyannikova, S.V.; Kimlenko, I.M.

    2002-01-01

    The fraction composition of humus substances of different type soils and soil solutions have been studied. A distribution of Pu 239, 240 and Am 241 between humus substances fractions of different dispersity and mobility in soil-vegetation cover has been established. It was shown that humus of organic soils fixes plutonium and americium in soil medium in greater extent than humus of mineral soils. That leads to lower migration ability of radionuclides in organic soils. The lower ability of americium to form difficultly soluble organic and organic-mineral complexes and predomination of its anion complexes in soil solutions may be a reason of higher mobility and biological availability of americium in comparison to plutonium during soil-plant transfer (authors)

  1. Transmutation of Americium in Light and Heavy Water Reactors

    Energy Technology Data Exchange (ETDEWEB)

    Hyland, B.; Dyck, G.R.; Edwards, G.W.R. [Chalk River Laboratories, Atomic Energy of Canada Limited (Canada); Ellis, R.J.; Gehin, J.C. [Oak Ridge National Laboratory (ORNL), Oak Ridge, Tennessee (United States); Maldonado, G.I. [University of Tennessee (Knoxville)/ORNL, Tennessee (United States)

    2009-06-15

    There is interest worldwide in reducing the burden on geological nuclear fuel disposal sites. In most disposal scenarios the decay heat loading of the surrounding rock limits the capacity of these sites. On the long term, this decay heat is generated primarily by actinides, and a major contributor 100 to 1000 years after discharge from the reactor is {sup 241}Am. One possible approach to reducing the decay-heat burden is to reprocess spent reactor fuel and use thermal spectrum reactors to 'burn' the Am nuclides. The viability of this approach is dependent upon the detailed changes in chemical and isotopic composition of actinide-bearing fuels after irradiation in thermal reactor spectra. The currently available thermal spectrum reactor options include light water-reactors (LWRs) and heavy-water reactors (HWRs) such as the CANDU{sup R} designs. In addition, as a result of the recycle of spent LWR fuel, there would be a considerable amount of potential recycled uranium (RU). One proposed solution for the recycled uranium is to use it as fuel in Candu reactors. This paper investigates the possibilities of transmuting americium in 'spiked' bundles in pressurized water reactors (PWRs) and in boiling water reactors (BWRs). Transmutation of Am in Candu reactors is also examined. One scenario studies a full core fuelled with homogeneous bundles of Am mixed with recycled uranium, while a second scenario places Am in an inert matrix in target channels in a Candu reactor, with the rest of the reactor fuelled with RU. A comparison of the transmutation in LWRs and HWRs is made, in terms of the fraction of Am that is transmuted and the impact on the decay heat of the spent nuclear fuel. CANDU{sup R} is a registered trademark of Atomic Energy of Canada Limited (AECL). (authors)

  2. The rapid determination of americium curium, and uranium in urine by ultrafiltration

    International Nuclear Information System (INIS)

    Stradling, G.N.; Popplewell, D.S.; Ham, G.J.; Griffin, R.

    1975-01-01

    The rapid ultrafiltration method developed for the assay of plutonium has been extended to the determination of americium, curium and uranium in urine. The limits of detection for americium and curium, and uranium are 0.09 and 0.12 dm -1 l -1 respectively, and the analysis time excluding counting less than 2 hours. The method can therefor be effectively used as a rapid screening procedure. When the reference level for plutonium is exceeded, the α activity may require to be characterised. The single ultrafiltration technique must be modified for turbid urine samples. The method is inappropriate, except for uranium, when the urine contains DTPA. (author)

  3. Carbamoyl methylphosphine oxide derivatives of adamantane as americium and europium extractants

    International Nuclear Information System (INIS)

    Babain, V.A.; Alyapyshev, M.Yu.; Novakov, I.A.; Orlinson, B.S.; Savel'ev, E.N.; Shokova, Eh.A.; Serebrayannikova, A.E.; Kovalev, V.V.

    2007-01-01

    Adamantane di-1,3-carbamoyl methylphosphine oxide (CMPO) derivatives, where CMPO-groups connect with 1,3-positions of rigid adamantane platform by methylene and ethylene bridges, are synthesized, and their efficiency as extractants of americium(III) and europium(III) from nitric acid solutions is demonstrated. Distribution function of Am 3+ and Eu + during extraction from 3M HNO 3 are measured in the investigation of extraction properties. It is noted that first synthesized adamantane CMPO derivatives are more effective for the extraction of americium(III) and europium(III) from 3MHNO 3 [ru

  4. Airborne plutonium and americium concentrations measured from the top of Rattlesnake Mountain

    International Nuclear Information System (INIS)

    Sehmel, G.A.

    1979-01-01

    Airborne plutonium-239+240 and americium-241 blowing from offsite was measured in an initial experiment at the top of Rattlesnake Mountain. Average airborne concentration measured was similar to fallout concentrations. Airborne plutonium concentrations were independent of wind speed for seven wind speed increments between 0.5 and 31 m/sec. In contrast the airborne americium concentration was a minimum at a wind speed of approximately 7 m/sec. Similarly, the airborne solids concentration in μg/m 3 was a minimum at an intermediate wind speed increment of 7 to 11 m/sec

  5. Experimental studies to validate model calculations and maximum solubility limits for Plutonium and Americium; Experimentelle Arbeiten zur Absicherung von Modellrechnungen und Maximalkonzentrationen fuer Plutonium und Americium

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2017-02-16

    This report focuses on studies of KIT-INE to derive a significantly improved description of the chemical behaviour of Americium and Plutonium in saline NaCl, MgCl{sub 2} and CaCl{sub 2} brine systems. The studies are based on new experimental data and aim at deriving reliable Am and Pu solubility limits for the investigated systems as well as deriving comprehensive thermodynamic model descriptions. Both aspects are of high relevance in the context of potential source term estimations for Americium and Plutonium in aqueous brine systems and related scenarios. Americium and Plutonium are long-lived alpha emitting radionuclides which due to their high radiotoxicity need to be accounted for in a reliable and traceable way. The hydrolysis of trivalent actinides and the effect of highly alkaline pH conditions on the solubility of trivalent actinides in calcium chloride rich brine solutions were investigated and a thermodynamic model derived. The solubility of Plutonium in saline brine systems was studied under reducing and non-reducing conditions and is described within a new thermodynamic model. The influence of dissolved carbonate on Americium and Plutonium solubility in MgCl{sub 2} solutions was investigated and quantitative information on Am and Pu solubility limits in these systems derived. Thermodynamic constants and model parameter derived in this work are implemented in the Thermodynamic Reference Database THEREDA owned by BfS. According to the quality assurance approach in THEREDA, is was necessary to publish parts of this work in peer-reviewed scientific journals. The publications are focused on solubility experiments, spectroscopy of aquatic and solid species and thermodynamic data. (Neck et al., Pure Appl. Chem., Vol. 81, (2009), pp. 1555-1568., Altmaier et al., Radiochimica Acta, 97, (2009), pp. 187-192., Altmaier et al., Actinide Research Quarterly, No 2., (2011), pp. 29-32.).

  6. 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)

    Murray, C.N.; Fukai, R.

    1975-01-01

    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 237 Pu 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)

  7. Determination of uranium isotopic composition and 236U content of soil samples and hot particles using inductively coupled plasma mass spectrometry.

    Science.gov (United States)

    Boulyga, S F; Becker, J S

    2001-07-01

    As a result of the accident at the Chernobyl nuclear power plant (NPP) the environment was contaminated with spent nuclear fuel. The 236U isotope was used in this study to monitor the spent uranium from nuclear fallout in soil samples collected in the vicinity of the Chernobyl NPP. Nuclear track radiography was applied for the identification and extraction of hot radioactive particles from soil samples. A rapid and sensitive analytical procedure was developed for uranium isotopic ratio measurement in environmental samples based on double-focusing inductively coupled plasma mass spectrometry (DF-ICP-MS) with a MicroMist nebulizer and a direct injection high-efficiency nebulizer (DIHEN). The performance of the DF-ICP-MS with a quartz DIHEN and plasma shielded torch was studied. Overall detection efficiencies of 4 x 10(-4) and 10(-3) counts per atom were achieved for 238U in DF-ICP-QMS with the MicroMist nebulizer and DIHEN, respectively. The rate of formation of uranium hydride ions UH+/U+ was 1.2 x 10(-4) and 1.4 x 10(-4), respectively. The precision of short-term measurements of uranium isotopic ratios (n = 5) in 1 microg L(-1) NBS U-020 standard solution was 0.11% (238U/235U) and 1.4% (236U/238U) using a MicroMist nebulizer and 0.25% (235U/238U) and 1.9% (236U/P38U) using a DIHEN. The isotopic composition of all investigated Chernobyl soil samples differed from those of natural uranium; i.e. in these samples the 236U/238U ratio ranged from 10(-5) to 10(-3). Results obtained with ICP-MS, alpha- and gamma-spectrometry showed differences in the migration properties of spent uranium, plutonium, and americium. The isotopic ratio of uranium was also measured in hot particles extracted from soil samples.

  8. Determination of uranium isotopic composition and 236U content of soil samples and hot particles using inductively coupled plasma mass spectrometry

    International Nuclear Information System (INIS)

    Boulyga, S.F.; Becker, J.S.

    2001-01-01

    As a result of the accident at the Chernobyl nuclear power plant (NPP) the environment was contaminated with spent nuclear fuel. The 236 U isotope was used in this study to monitor the spent uranium from nuclear fallout in soil samples collected in the vicinity of the Chernobyl NPP. Nuclear track radiography was applied for the identification and extraction of hot radioactive particles from soil samples. A rapid and sensitive analytical procedure was developed for uranium isotopic ratio measurement in environmental samples based on double-focusing inductively coupled plasma mass spectrometry (DF-ICP-MS) with a MicroMist nebulizer and a direct injection high-efficiency nebulizer (DIHEN). The performance of the DF-ICP-MS with a quartz DIHEN and plasma shielded torch was studied. Overall detection efficiencies of 4 x 10 -4 and 10 -3 counts per atom were achieved for 238 U in DF-ICP-QMS with the MicroMist nebulizer and DIHEN, respectively. The rate of formation of uranium hydride ions UH + /U + was 1.2 x 10 -4 and 1.4 x 10 -4 , respectively. The precision of short-term measurements of uranium isotopic ratios (n = 5) in 1 μg L -1 NBS U-020 standard solution was 0.11% ( 238 U/ 235 U) and 1.4% ( 236 U/ 238 U) using a MicroMist nebulizer and 0.25% ( 235 U/ 238 U) and 1.9% ( 236 U/ 238 U) using a DIHEN. The isotopic composition of all investigated Chernobyl soil samples differed from those of natural uranium; i.e. in these samples the 236 U/ 238 U ratio ranged from 10 -5 to 10 -3 . Results obtained with ICP-MS, α- and γ-spectrometry showed differences in the migration properties of spent uranium, plutonium, and americium. The isotopic ratio of uranium was also measured in hot particles extracted from soil samples. (orig.)

  9. 49 CFR Appendix A to Part 236 - Civil Penalties 1

    Science.gov (United States)

    2010-10-01

    ... 1,000 2,000 236.329Bolt lock 1,000 2,000 236.330Locking dog of switch and lock movement 1,000 2,000....338Mechanical locking required in accordance with locking sheet and dog chart 1,000 2,000 236.339Mechanical... next available point of communication after automatic train stop, train control, or cab signal device...

  10. Plutonium-239 and americium-241 uptake by plants from soil. Final report

    International Nuclear Information System (INIS)

    Brown, K.W.

    1979-03-01

    Alfalfa was grown in soil contaminated with plutonium-239 dioxide (239PuO2) at a concentration of 29.7 nanocuries per gram (nCi/g). In addition to alfalfa, radishes, wheat, rye, and tomatoes were grown in soils contaminated with americium-241 nitrate (241Am(NO3)3) at a concentration of 189 nCi/g. The length of exposure varied from 52 days for the radishes to 237 days for the alfalfa. The magnitude of plutonium incorporation by the alfalfa as indicated by the concentration ratio, 0.0000025, was similar to previously reported data using other chemical forms of plutonium. The results did indicate, however, that differences in the biological availability of plutonium isotopes do exist. All of the species exposed to americium-241 assimilated and translocated this radioisotope to the stem, leaf, and fruiting structures. The magnitude of incorporation as signified by the concentration ratios varied from 0.00001 for the wheat grass to 0.0152 for the radishes. An increase in the uptake of americium also occurred as a function of time for four of the five plant species. Evidence indicates that the predominant factor in plutonium and americium uptake by plants may involve the chelation of these elements in soils by the action of compounds such as citric acid and/or other similar chelating agents released from plant roots

  11. Possibility of obtaining enriched americium-242g by the elution of recoil atoms from zeolite

    Energy Technology Data Exchange (ETDEWEB)

    Shafiev, A I; Vityutnev, V M; Ivanov, V M; Yakovlev, G N

    1974-12-31

    On the example of production the possibility of obtaining enriched actinide isotopes by the elution of recotl atoms with the use of a zeolite- americium-241 target was shown. The enrichment factor and the recoil atoms of / sup 242g/Am yield depend on preliminary target treatment and solution composition used for elution. (auth)

  12. Environmental impacts of the release of a transuranic actinide, americium-241, from a contaminated facility

    Energy Technology Data Exchange (ETDEWEB)

    Want, J.; Merry-Libby, P.

    1985-10-29

    Americium-241 is widely used as a radiation source, but it also has some potential risk if taken into the body because of its high dose conversion factor. Although the radiotoxicity of americium-241 is small compared to other transuranic actinides, its effects on the reproductive system and on development of the placenta are more damaging than the effects of plutonium-239. In Ohio, a gemologist's laboratory was contaminated with americium-241. Prior to decontamination of the laboratory, potential radiological impacts to the surrounding environment were assessed. A hypothetical fire accident resulting in a unit release (1 curie) was assumed. Potential radiological impacts were simulated using an atmospheric dispersion and dosimetry model with local meteorological data, population census data, and detailed information regarding the neighborhood. The results indicate that there could have been a significant impact on nearby residents from americium-241 via atmospheric dispersion if a major catastrophic release had occurred prior to contamination and decommissioning of the laboratory. 14 refs., 3 figs., 2 tabs.

  13. Explosion of cation exchange column in americium recovery service, Hanford plant, August 30, 1976

    International Nuclear Information System (INIS)

    1976-01-01

    This document is a collection of thirty references related to the explosion of the cation exchange column in the Americium Recovery Service of the Hanford Atomic Products Operation, Richland, Washington, on August 30, 1976. Some of the documents are related to the design and safety studies, while others refer to the accident and resulting decontamination efforts, investigations, and legal consequences

  14. Total and Compound Formation Cross Sections for Americium Nuclei: Recommendations for Coupled-Channels Calculations

    Energy Technology Data Exchange (ETDEWEB)

    Escher, J. E. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2017-04-11

    Calculations for total cross sections and compound-nucleus (CN) formation cross sections for americium isotopes are described, for use in the 2017 NA-22 evaluation effort. The code ECIS 2006 was used in conjunction with Frank Dietrich's wrapper `runtemplate'.

  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

    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 co...

  16. National low-level waste management program radionuclide report series, Volume 14: Americium-241

    International Nuclear Information System (INIS)

    Winberg, M.R.; Garcia, R.S.

    1995-09-01

    This report, Volume 14 of the National Low-Level Waste Management Program Radionuclide Report Series, discusses the radiological and chemical characteristics of americium-241 ( 241 Am). This report also includes discussions about waste types and forms in which 241 Am can be found and 241 Am behavior in the environment and in the human body

  17. Radiochemical separation and alpha-spectrometric determination of Americium in different matrixes

    International Nuclear Information System (INIS)

    Radenkovic, M.; Joksic, J.; Paligoric, D.

    2009-01-01

    A method of separation and alpha-spectrometric determination of americium, developed in VINCA Institute of Nuclear Sciences is described in the paper. The procedure is convenient to be used for 241 Am determination in environmental matrixes as well as samples of human origin if a very small concentrations are expected, using 243 Am as a tracer for radiochemical yield recovery. (author) [sr

  18. Biokinetic study of plutonium and americium associated to the particulates of soil

    International Nuclear Information System (INIS)

    Espinosa, A.; Aragon, A.; Martinez, J.; Iranzo, C.E.

    1996-01-01

    The object of this study is to determine the biokinetic parameters of different Plutonium isotopes and Americium inhaled in the state in which they are found in the environment as a result of their deposition in the soil, from an aviation accident that generated different plutonium oxides. to achieve this objective, two lines of work planned. One was the determination of the mineralogical composition and associations that plutonium and americium present in that soil 22 years after the nuclear accident. Other studies were directed to determine the biokinetic of the plutonium isotopes and americium (contained in the dust) deposited tracheally and inhaled by laboratory animals (rats) and in vitro experiments by pulmonary leaching simulation. The in vivo tests have been developed in NRPB (U.K.) and the in vitro experiment, geochemical associations studies, assessment of internal doses to humans resulting from intake of plutonium and americium bearing dusts present in the contaminated area and establishment of ALIs for inhalation, were carried out in CIEMAT (Spain). In this work only determinations and experiments carried out by CIEMAT are includes as a part of the EU Project ''INHALATION AND INGESTION OF RADIONUCLIDES'' contract: FI3P-CT920064a. (Author) 10 refs

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

    International Nuclear Information System (INIS)

    Vives i Batlle, J.

    1993-12-01

    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)

  20. 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

  1. 7 CFR 205.236 - Origin of livestock.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 3 2010-01-01 2010-01-01 false Origin of livestock. 205.236 Section 205.236... livestock. (a) Livestock products that are to be sold, labeled, or represented as organic must be from livestock under continuous organic management from the last third of gestation or hatching: Except, That: (1...

  2. 7 CFR 2.36 - Director, Office of Communications.

    Science.gov (United States)

    2010-01-01

    ... are made by the Secretary of Agriculture to Director, Office of Communications: (1) Related to public...) Organize and direct the activities of a public affairs office to include press relations of the secretary... 7 Agriculture 1 2010-01-01 2010-01-01 false Director, Office of Communications. 2.36 Section 2.36...

  3. 49 CFR 236.825 - System, automatic train control.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false System, automatic train control. 236.825 Section..., INSPECTION, MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Definitions § 236.825 System, automatic train control. A system so arranged that its operation will automatically...

  4. 49 CFR 236.813a - State, most restrictive.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false State, most restrictive. 236.813a Section 236.813a Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION... State, most restrictive. The mode of an electric or electronic device that is equivalent to a track...

  5. 49 CFR 236.766 - Locking, movable bridge.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Locking, movable bridge. 236.766 Section 236.766... Locking, movable bridge. The rail locks, bridge locks, bolt locks, circuit controllers, and electric locks used in providing interlocking protection at a movable bridge. ...

  6. 8 CFR 236.5 - Fingerprints and photographs.

    Science.gov (United States)

    2010-01-01

    ... 8 Aliens and Nationality 1 2010-01-01 2010-01-01 false Fingerprints and photographs. 236.5 Section... to Order of Removal § 236.5 Fingerprints and photographs. Every alien 14 years of age or older... photographs shall be made available to Federal, State, and local law enforcement agencies upon request to the...

  7. 8 CFR 236.2 - Confined aliens, incompetents, and minors.

    Science.gov (United States)

    2010-01-01

    ... 8 Aliens and Nationality 1 2010-01-01 2010-01-01 false Confined aliens, incompetents, and minors. 236.2 Section 236.2 Aliens and Nationality DEPARTMENT OF HOMELAND SECURITY IMMIGRATION REGULATIONS APPREHENSION AND DETENTION OF INADMISSIBLE AND DEPORTABLE ALIENS; REMOVAL OF ALIENS ORDERED REMOVED Detention...

  8. 49 CFR 236.102 - Semaphore or searchlight signal mechanism.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Semaphore or searchlight signal mechanism. 236.102... Instructions: All Systems Inspections and Tests; All Systems § 236.102 Semaphore or searchlight signal mechanism. (a) Semaphore signal mechanism shall be inspected at least once every six months, and tests of...

  9. 49 CFR 236.810 - Spectacle, semaphore arm.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Spectacle, semaphore arm. 236.810 Section 236.810 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION... Spectacle, semaphore arm. That part of a semaphore arm which holds the roundels and to which the blade is...

  10. 49 CFR 236.527 - Roadway element insulation resistance.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Roadway element insulation resistance. 236.527 Section 236.527 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD... element insulation resistance. Insulation resistance between roadway inductor and ground shall be...

  11. 27 CFR 24.236 - Losses of spirits.

    Science.gov (United States)

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Losses of spirits. 24.236... OF THE TREASURY LIQUORS WINE Spirits § 24.236 Losses of spirits. Losses by theft or any other cause... the losses are discovered. A physical inventory of the spirits storage tanks will be taken at the...

  12. 49 CFR 236.786 - Principle, closed circuit.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Principle, closed circuit. 236.786 Section 236.786 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION... Principle, closed circuit. The principle of circuit design where a normally energized electric circuit which...

  13. 49 CFR 236.1043 - Task analysis and basic requirements.

    Science.gov (United States)

    2010-10-01

    ... Train Control Systems § 236.1043 Task analysis and basic requirements. (a) Training structure and... classroom, simulator, computer-based, hands-on, or other formally structured training designed to impart the... 49 Transportation 4 2010-10-01 2010-10-01 false Task analysis and basic requirements. 236.1043...

  14. 49 CFR 236.923 - Task analysis and basic requirements.

    Science.gov (United States)

    2010-10-01

    ... for Processor-Based Signal and Train Control Systems § 236.923 Task analysis and basic requirements... structured training designed to impart the knowledge, skills, and abilities identified as necessary to... 49 Transportation 4 2010-10-01 2010-10-01 false Task analysis and basic requirements. 236.923...

  15. 49 CFR 236.1033 - Communications and security requirements.

    Science.gov (United States)

    2010-10-01

    ... Train Control Systems § 236.1033 Communications and security requirements. (a) All wireless... 49 Transportation 4 2010-10-01 2010-10-01 false Communications and security requirements. 236.1033... exceeding the security strength required to protect the data as defined in the railroad's PTCSP and required...

  16. 7 CFR 58.236 - Pasteurization and heat treatment.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 3 2010-01-01 2010-01-01 false Pasteurization and heat treatment. 58.236 Section 58... Service 1 Operations and Operating Procedures § 58.236 Pasteurization and heat treatment. All milk and... is handled according to sanitary conditions approved by the Administrator. (a) Pasteurization. (1...

  17. 49 CFR 236.18 - Software management control plan.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Software management control plan. 236.18 Section... Instructions: All Systems General § 236.18 Software management control plan. (a) Within 6 months of June 6, 2005, each railroad shall develop and adopt a software management control plan for its signal and train...

  18. Excess of {sup 236}U in the northwest Mediterranean Sea

    Energy Technology Data Exchange (ETDEWEB)

    Chamizo, E., E-mail: echamizo@us.es [Centro Nacional de Aceleradores, Universidad de Sevilla, Consejo Superior de Investigaciones Científicas, Junta de Andalucía, Thomas Alva Edison 7, 41092 Seville (Spain); López-Lora, M., E-mail: mlopezlora@us.es [Centro Nacional de Aceleradores, Universidad de Sevilla, Consejo Superior de Investigaciones Científicas, Junta de Andalucía, Thomas Alva Edison 7, 41092 Seville (Spain); Bressac, M., E-mail: matthieu.bressac@utas.edu.au [IAEA-Environment Laboratories, Monte Carlo 98000 (Monaco); Institute for Marine and Antarctic Studies, University of Tasmania, Hobart, TAS (Australia); Levy, I., E-mail: I.N.Levy@iaea.org [IAEA-Environment Laboratories, Monte Carlo 98000 (Monaco); Pham, M.K., E-mail: M.Pham@iaea.org [IAEA-Environment Laboratories, Monte Carlo 98000 (Monaco)

    2016-09-15

    In this work, we present first {sup 236}U results in the northwestern Mediterranean. {sup 236}U is studied in a seawater column sampled at DYFAMED (Dynamics of Atmospheric Fluxes in the Mediterranean Sea) station (Ligurian Sea, 43°25′N, 07°52′E). The obtained {sup 236}U/{sup 238}U atom ratios in the dissolved phase, ranging from about 2 × 10{sup −9} at 100 m depth to about 1.5 × 10{sup −9} at 2350 m depth, indicate that anthropogenic {sup 236}U dominates the whole seawater column. The corresponding deep-water column inventory (12.6 ng/m{sup 2} or 32.1 × 10{sup 12} atoms/m{sup 2}) exceeds by a factor of 2.5 the expected one for global fallout at similar latitudes (5 ng/m{sup 2} or 13 × 10{sup 12} atoms/m{sup 2}), evidencing the influence of local or regional {sup 236}U sources in the western Mediterranean basin. On the other hand, the input of {sup 236}U associated to Saharan dust outbreaks is evaluated. An additional {sup 236}U annual deposition of about 0.2 pg/m{sup 2} based on the study of atmospheric particles collected in Monaco during different Saharan dust intrusions is estimated. The obtained results in the corresponding suspended solids collected at DYFAMED station indicate that about 64% of that {sup 236}U stays in solution in seawater. Overall, this source accounts for about 0.1% of the {sup 236}U inventory excess observed at DYFAMED station. The influence of the so-called Chernobyl fallout and the radioactive effluents produced by the different nuclear installations allocated to the Mediterranean basin, might explain the inventory gap, however, further studies are necessary to come to a conclusion about its origin. - Highlights: • First {sup 236}U results in the northwest Mediterranean Sea are reported. • Anthropogenic {sup 236}U dominates the whole seawater column at DYFAMED station. • {sup 236}U deep-water column inventory exceeds by a factor of 2.5 the global fallout one. • Saharan dust intrusions are responsible for an annual

  19. Local Structure in Americium and Californium Hexa-cyanoferrates - Comparison with Their Lanthanide Analogues

    International Nuclear Information System (INIS)

    Dupouy, G.; Bonhoure, I.; Dumas, Th.; Moisy, Ph.; Petit, S.; Den Auwer, Ch.; Conradson, St.D.; Hennig, Ch.; Scheinost, A.C.; Le Naour, C.; Simoni, E.

    2011-01-01

    Metal hexa-cyanoferrates are well known molecular solids for a large variety of cations, although very little has been described for actinide adducts. Two new members of actinide(III) hexa-cyanoferrates were synthesized with the cations americium and californium. They were structurally characterized by infrared and X-ray absorption spectroscopy. Combined EXAFS data at the iron K edge and actinide L 3 edge provide evidence for a three-dimensional model for these two new compounds. Structural data in terms of bond lengths were compared to those reported for the parent lanthanide(III) compounds, neodymium and gadolinium hexa-cyanoferrates, respectively: the americium compound with (KNd(III)Fe(II)-Fe-III(CN) 6 .4H 2 O and the californium compound with (KGd(III)Fe(II)(CN) . 3.5H 2 O and (KGd(III)Fe(II)(CN) 6 .3H 2 O. This comparison between actinide and lanthanide homologues has been carried out on the basis of ionic radii considerations. The americium and neodymium environments appear to be very similar and are arranged in a tri-capped trigonal prism polyhedron of coordination number 9 (CN: 9), in which the americium atom is bonded to six nitrogen atoms and to three water molecules. For the californium adduct, a similar comparison and bond length and angle values derived from EXAFS studies suggest that the californium cation sits in a bi-capped trigonal prism (CN: 8) as in (KGd(III)Fe(II)(CN) 6 . 3H 2 O. This arrangement differs from that in the structure of (KGd(III)Fe(II)(CN) 6 .3.5H 2 O, in which the gadolinium atom is surrounded by 9 atoms. This is one of the rare pieces of information revealed by EXAFS spectroscopy for americium and californium in comparison to lanthanide atoms in molecular solid compounds. A discussion on the decrease in bond length and coordination number from americium to californium is also provided, on the basis of crystallographic results reported in the literature for actinide(III) and lanthanide(III) hydrate series. (authors)

  20. Electric resistivity of 241-americium and 244-curium metals. Creation of defects and isochronous annealing of 241-americium metal after self-irradiation

    International Nuclear Information System (INIS)

    Schenkel, R.

    1977-03-01

    The temperature dependence of the electrical resistivity of thin films of bulk 241 Am metal were measured between 300 and 4.5 K. The room temperature resistivity was found to be 68.90μΩcm. At room temperature the electrical resistivity of americium increases with pressure (3% up to 13 kbar). The application of 13 kbar pressure did not change the low temperature power law in the electrical resistivity. The resistivity vs temperature curve can be explained by assuming s-d scattering of conduction electrons. The localized 5f electrons are considered to be about 5eV below the Fermi level. Americium therefore should be the first lanthanide-like element in the actinide series. The defect production due to self-irradiation damage was studied by measuring the increase of the resistivity at 4.2 K over a period of 738 h. A saturation resistivity of 16.036 μΩcm was found corresponding to a defect concentration of about 0.22 a/o. After isochronal annealing two recovery stages were observed at about 65 and 145 K. The two stages shift with increasing initial defect concentration to lower temperatures. Estimates of the activation energies and the reaction order were made and possible defect reactions suggested. The magnetic contribution to the electrical resistivity of curium, which shows an antiferromagnetic transition at 52.5 k, was obtained by subtracting the resistivity of americium (to be considered as phonon part). Comparison with theoretical models were made. At low temperatures the measurements are strongly affected by self-irradiation damage [drho/dt(t=0)=9.8μΩcm/h

  1. Structural characterisations and mechanistic investigations of the selective dissolution of americium by the ferricyanide ions in alkaline media. Application for the partitioning americium curium

    International Nuclear Information System (INIS)

    Fouchard, Sebastien

    2000-01-01

    Americium exhibits a high solubility form in basic media under oxidant conditions, unlike the other Transplutonium elements (TPE). This property can be used in the frame of High Level Liquid Waste (HLLW) treatment in order to extract preferentially the americium element, the main responsible of the long term radiotoxicity of the nuclear waste. This soluble compound can be obtained by addition of a concentrated basic solution of Fe(CN) 6 3- ions on Am(OH) 3 precipitates. This technique enables a rapid extraction of Am by the synthesis of this soluble form in alkaline solutions. Under these conditions, the other TPE remain in the solid state as trivalent hydroxide solids, strongly insoluble. In the case of dissolutions involving large amounts of Am(OH) 3 , the formation of the soluble complex is concomitant with the appearance of a reddish precipitate in the basic solution. Dissolution experiments which were carried out on this solid in NaOH/Fe(CN) 6 3- have demonstrated the dependency of the solubility equilibria with the media. Spectroscopic studies (UV Visible, XAS) on the precipitate have enabled the determination of the chemical structure and the oxidation state of the americium in the solid: Na 2 Am(V)O 2 (OH) 3 ,nH 2 O. Electrochemical studies on the americium solution have confirmed that the oxidation of Am(OH) 3 by the Fe(CN) 6 3- ions in basic media could only lead to the pentavalent form. A stoichiometric study carries out between a AmO 2 + ion and one Fe(CN) 6 3- ion and the spectroscopic characterisation of this reaction have demonstrated that the Fe(CN) 6 3- ion didn't remain as an un-complexed form in solution after the alkaline mixing. These results tend to prove that this dissolution of Am(OH) 3 is much more complex than a simple oxidation by the Fe(CN) 6 3- ions. The existence of molecular interactions between AmO 2 + and Fe(CN) 6 3- has been postulated and a mechanistic scheme has been proposed in order to explain the appearance of the soluble

  2. 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).

  3. Mycoremediation. The study of transfer factor for plutonium and americium uptake from the ground

    International Nuclear Information System (INIS)

    Dusan Galanda; Lubomir Matel; Jana Strisovska; Silvia Dulanska

    2014-01-01

    In our scientific research we have monitored mycoremediation's properties of oyster mushrooms in cultivation on the soil what is contaminated by solutions with radioactive isotopes of 239 Pu and 241 Am with known activity. We monitored specific activities of absorbed radionuclides in fruiting bodies and chemical forms of radionuclides which were compared to calculated specific activities of two background samples of oyster mushrooms intended for consumer purpose. We determined distributive coefficients between the ground and the fruiting body of oyster mushrooms. The average value which was obtained for the transfer factor for plutonium was 0.72 and for americium 3.97. To evaluate a quantity of absorbed radionuclides we used a method of liquid extraction. The emitting alpha radiation of alpha radionuclides was detected by spectrometry. For defining individual fractions of plutonium and americium that are contained in mushroom bodies was used the sequential leaching method. (author)

  4. 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.

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

    International Nuclear Information System (INIS)

    Raison, P.E.

    2001-01-01

    Presented are studies involving the incorporation of americium and curium in zirconia-based materials. First explored was the pseudo ternary system AmO 2 -ZrO 2 -Y 2 O 3 . 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 AmO 2 content. The Cm 2 O 3 -ZrO 2 system was also investigated. It was found that at 25 mol% of CmO 1.5 , 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 CmO 1.5 , a pyrochlore oxide - Cm 2 Zr 2 O 7 - is formed (a = 10.63 ±0.02 Angstrom). (author)

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

    International Nuclear Information System (INIS)

    Papenia, M.V.; Sokolik, G.A.; Ovsiannikova, S.V.; Voinikava, E.V.; Svirschevsky, S.F.; Brown, J.; Skipperud, L.

    2010-01-01

    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

  7. High-purity germanium detection system for the in vivo measurement of americium and plutonium

    International Nuclear Information System (INIS)

    Tyree, W.H.; Falk, R.B.; Wood, C.B.; Liskey, R.W.

    1976-01-01

    A high-purity germanium (HPGe) array, photon-counting system has been developed for the Rocky Flats Plant Body-Counter Medical Facility. The newly improved system provides exceptional resolutions of low-energy X-ray and gamma-ray spectra associated with the in vivo deposition of plutonium and americium. Described are the operational parameters of the system and some qualitative results illustrating detector performance for the photon emissions produced from the decay of plutonium and americium between energy ranges from 10 to 100 kiloelectron volts. Since large amounts of data are easily generated with the system, data storage, analysis, and computer software developments continue to be an essential ingredient for processing spectral data obtained from the detectors. Absence of quantitative data is intentional. The primary concern of the study was to evaluate the effects of the various physical and electronic operational parameters before adding those related entirely to a human subject

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

    International Nuclear Information System (INIS)

    Laplace, A.; Lacquement, J.; Maillard, C.; Donner, L.

    2004-01-01

    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 AmO 2 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-AmCl 3 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)

  9. Quantitative determination of americium and curium in solutions using potassium tungstophosphate

    International Nuclear Information System (INIS)

    Chistyakov, V.M.; Baranov, A.A.; Erin, E.A.; Timoaeev, G.A.

    1990-01-01

    Two methods of americium (4) and curium (4) titration-replacement and redox ones - have been considered. According to the replacement method thorium nitrate solution was used as a titrant and the final point of titration was determined spectophotometrically. Using the method developed, on the basis of experimental data, the composition of thorium (4) complex with potassium tungstophosphate was determined. In case of the redox titration sodium nitrite was used, and the final titration point was indicated either spectrophotometrically or potentiometrically

  10. Determination of americium and plutonium in autopsy tissue: methods and problems

    International Nuclear Information System (INIS)

    Boyd, H.A.; Eutsler, B.C.; McInroy, J.F.

    1979-01-01

    The current methods used by the tissue analysis program at LASL for the determination of americium and plutonium in autopsy tissue are described. Problems affecting radiochemical yield are discussed. Included are problems associated with sample preparation, separation of plutonium from large amounts of bone ash, and reagent contamination. The average 242 Pu tracer yield for 1800 Pu determinations is 78 +- 12%. The average 242 Am tracer yield is 85 +- 7% for 40 determinations

  11. 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.

  12. Experimental studies to validate model calculations and maximum solubility limits for Plutonium and Americium

    International Nuclear Information System (INIS)

    2017-01-01

    This report focuses on studies of KIT-INE to derive a significantly improved description of the chemical behaviour of Americium and Plutonium in saline NaCl, MgCl 2 and CaCl 2 brine systems. The studies are based on new experimental data and aim at deriving reliable Am and Pu solubility limits for the investigated systems as well as deriving comprehensive thermodynamic model descriptions. Both aspects are of high relevance in the context of potential source term estimations for Americium and Plutonium in aqueous brine systems and related scenarios. Americium and Plutonium are long-lived alpha emitting radionuclides which due to their high radiotoxicity need to be accounted for in a reliable and traceable way. The hydrolysis of trivalent actinides and the effect of highly alkaline pH conditions on the solubility of trivalent actinides in calcium chloride rich brine solutions were investigated and a thermodynamic model derived. The solubility of Plutonium in saline brine systems was studied under reducing and non-reducing conditions and is described within a new thermodynamic model. The influence of dissolved carbonate on Americium and Plutonium solubility in MgCl 2 solutions was investigated and quantitative information on Am and Pu solubility limits in these systems derived. Thermodynamic constants and model parameter derived in this work are implemented in the Thermodynamic Reference Database THEREDA owned by BfS. According to the quality assurance approach in THEREDA, is was necessary to publish parts of this work in peer-reviewed scientific journals. The publications are focused on solubility experiments, spectroscopy of aquatic and solid species and thermodynamic data. (Neck et al., Pure Appl. Chem., Vol. 81, (2009), pp. 1555-1568., Altmaier et al., Radiochimica Acta, 97, (2009), pp. 187-192., Altmaier et al., Actinide Research Quarterly, No 2., (2011), pp. 29-32.).

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

    Energy Technology Data Exchange (ETDEWEB)

    Hoppenheit, M.; Murray, C.N.; Woodhead, D.S.

    1980-01-01

    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.

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

    International Nuclear Information System (INIS)

    Hoppenheit, M.; Murray, C.N.; Woodhead, D.S.

    1980-01-01

    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.) [de

  15. Adsorption-Desorption Characteristics of Plutonium and Americium with Sediment Particles in the Estuarine Environment

    International Nuclear Information System (INIS)

    Murray, C.N.; Fukai, R.

    1976-01-01

    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 237 Pu was in particulate form, larger than 0.45pm, 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)

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

    Energy Technology Data Exchange (ETDEWEB)

    Salminen, S.

    2009-07-01

    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 test site, and Sodankylae (Finland). The origin of plutonium is almost impossible to identify at Kurchatov, since hundreds of nuclear tests were performed at the Semipalatinsk test site. In Sodankylae, plutonium in the surface air originated from nuclear weapons testing, conducted mostly by USSR and USA before the sampling year 1963. The variation in americium, curium and neptunium concentrations was great as well in peat samples collected in southern and central Finland in 1986 immediately after the Chernobyl accident. The main source of transuranium contamination in peats was from global nuclear test fallout, although there are wide regional differences in the fraction of Chernobyl-originated activity (of the total activity) for americium, curium and neptunium. The separation methods developed in this study yielded good chemical recovery for the elements investigated and adequately pure fractions for radiometric activity determination. The extraction chromatographic methods were faster compared to older methods based on ion exchange chromatography. In addition, extraction chromatography is a more environmentally friendly separation method than ion exchange, because less acidic waste solutions are produced during the analytical procedures. (orig.)

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

    International Nuclear Information System (INIS)

    Boggs, S. Jr.; Seitz, M.G.

    1984-01-01

    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 22 0 C, 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 90 0 C 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 22 0 C 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

  18. Remobilization of americium in soil columns under experimental rhizo-spheric conditions

    Energy Technology Data Exchange (ETDEWEB)

    Perrier, T.; Martin-Garin, A.; Morello, M. [CEA Cadarache (DEI/SECRE/LRE), Laboratory of Radioecology and Ecotoxicology, Institute for Radioprotection and Nuclear Safety, 13 - Saint-Paul-lez-Durance (France)

    2004-07-01

    The biogeochemical behaviour of americium in subsurface soils plays a dominant role on the potential migration of this actinide, but is currently poorly known. The identification and understanding of these processes is of major concern for this highly (radio)toxic element and can allow the determination of its impact on the natural media. This research investigates the relevant processes controlling americium biogeochemical speciation in the rhizosphere of an agricultural soil. Lixiviation tests were performed on columns packed with a 2 mm-sieved calcareous soil contaminated with {sup 241}Am (500 Bq.g{sup -1}), under steady-state unsaturated or saturated hydric flow conditions. The columns were percolated with soil solution of varied compositions, containing citrate and/or glucose simulating root exudates in non-sterile conditions. The physico-chemical parameters of the outlet solution (pH, conductivity, major ions, organic acids) were monitored, as well as the microbial activity. Inorganic and organic speciation of {sup 241}Am is supported by geochemical modeling with JChess, using a thermodynamic database based on NEA database and the latest PSI recommendations. The percolation of a solution in equilibrium with the soil released small amount of americium (<5 mBq/cm{sup 3}), as predicted by the high {sup 241}Am K{sub d} values. 10{sup -4} M concentrations of citrate, glucose or both combined did not enhance remobilization either. Poor remobilization was also observed at high glucose concentrations (10{sup -2} M), despite an effective glucose microbial degradation, the production of ligands such as acetate, and important changes in the chemistry of the solution. On the contrary, high concentrations of citrate (10{sup -2} M) released 1000 times more americium, which is in accordance with previous studies. Even greater releases (10000 times) were observed when 10{sup -2} M glucose was added to 10{sup -2} M citrate. The remobilization of americium resulting from the

  19. Phenotype abnormality: 236 [Arabidopsis Phenome Database[Archive

    Lifescience Database Archive (English)

    Full Text Available 236 http://metadb.riken.jp/db/SciNetS_ria224i/cria224u1ria224u742i decreased susceptibility... in response to organism Agrobacterium ... Agrobacterium ... decreased susceptibility toward ...

  20. 48 CFR 852.236-89 - Buy American Act.

    Science.gov (United States)

    2010-10-01

    ... contained in this clause 852.236-89 are waived for World Trade Organization (WTO) Government Procurement... not anticipate accepting an offer that includes foreign construction material, other than WTO GPA...

  1. Dicty_cDB: SFH236 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available SF (Link to library) SFH236 (Link to dictyBase) - G00315 DDB0191340 Contig-U16349-1...brary) Clone ID SFH236 (Link to dictyBase) Atlas ID - NBRP ID G00315 dictyBase ID DDB0191340 Link to Contig ...Contig-U16349-1 Original site URL http://dictycdb.biol.tsukuba.ac.jp/CSM/SF/SFH2-...VDCVTNSSDASCTNFQYPLANITADINNL CGSMPYMPVCTIQQSCNQESSTSGICDPFSILGDSCLHDMPGMSG--- ---ASGSVVEQCSSVDSISNLPTTMQLFAGIKSICT...ii yvvaclicqfvpfnnhviknpqqvvfvihsqflvivvfticqa*vv--- ---ASGSVVEQCSSVDSISNLPTTMQLFAGIKSICTEMAMDGCEKCSGNSPTTTC

  2. An experimental investigation of accumulation and transmutation behavior of americium in the MOX fuel irradiated in a fast reactor

    International Nuclear Information System (INIS)

    Osaka, Masahiko; Koyama, Shin-ichi; Maeda, Shigetaka; Mitsugashira, Toshiaki

    2005-01-01

    Americium isotopes generated in the MOX fuel irradiated in the experimental fast reactor JOYO were analyzed by applying a sophisticated radiochemical technique. Americium was isolated from the irradiated MOX fuel by a combined method of anion-exchange chromatography and oxidation of Am. The isotopic ratios of americium and its content were determined by thermal ionization mass spectroscopy and α-spectrometry, respectively. The americium isotopic ratio was similar for all the specimens, but was significantly different from that of PWR-MOX. On the basis of present analytical results, the accumulation and transmutation behavior of americium nuclides in a fast reactor is discussed from the viewpoints of neutron spectrum dependence and the isomeric ratio of the 241 Am capture reaction. The estimated isomeric ratio is about 87%, which is close to the latest evaluated value. A rapid estimation method of Am content by using the 240 Pu to 239 Pu ratio was adopted and proved to be valid for the spent fuel irradiated in the fast reactor

  3. 48 CFR 252.236-7000 - Modification proposals-price breakdown.

    Science.gov (United States)

    2010-10-01

    ...-price breakdown. 252.236-7000 Section 252.236-7000 Federal Acquisition Regulations System DEFENSE... CLAUSES Text of Provisions And Clauses 252.236-7000 Modification proposals—price breakdown. As prescribed in 236.570(a), use the following clause: Modification Proposals—Price Breakdown (DEC 1991) (a) The...

  4. Accumulation of americium-241 in the biomass of aquatic plants of the Yenisei river: experimental study

    Energy Technology Data Exchange (ETDEWEB)

    Zotina, T.A.; Bolsunovsky, A.Y.A.; Bondareva, L.G. [Institute of Biophysics SB RAS, Akademgorodok, Krasnoyarsk (Russian Federation)

    2004-07-01

    Due to the operation of the Mining-and-Chemical Combine (Krasnoyarsk-26), which has been manufacturing weapons-grade plutonium for several decades, the Yenisei River is contaminated with transuranic elements (including {sup 241}Am). {sup 241}Am was found in the riverside soil, sediment and in the biomass of aquatic plants (Bolsunovsky et al., 1999, 2002). Aquatic plants are an important link in the migration of radionuclides in an aquatic ecosystem. In laboratory experiments, we investigated accumulation of {sup 241}Am by the submerged macrophyte from the Yenisei River: the pond weed (Elodea canadensis) and the aquatic moss (Fontinalis antipyretica), and release of {sup 241}Am from the biomass. The content of {sup 241}Am was measured on a Canberra (USA) gamma-spectrometer. The experiments showed that specific accumulation and concentration factors of {sup 241}Am in the plants were in inverse proportion to their biomass. We obtained new data on release of {sup 241}Am from the biomass of macrophyte. Americium-241 was more firmly fixed in the biomass of the aquatic moss. In 12 months, the biomass of the aquatic moss released about 30% of the initial americium activity into the water. To compare, the biomass of the pond weed released into the water medium up to 64% of the initial {sup 241}Am activity in 1.5 4 months. The release rate was dependent on the decomposition rate of the plant biomass. The experiments showed that submerged macrophyte of the Yenisei River can accumulate considerable activities of {sup 241}Am and retain americium for long periods of time in biomass. (author)

  5. Accumulation of americium-241 in the biomass of aquatic plants of the Yenisei river: experimental study

    International Nuclear Information System (INIS)

    Zotina, T.A.; Bolsunovsky, A.Y.A.; Bondareva, L.G.

    2004-01-01

    Due to the operation of the Mining-and-Chemical Combine (Krasnoyarsk-26), which has been manufacturing weapons-grade plutonium for several decades, the Yenisei River is contaminated with transuranic elements (including 241 Am). 241 Am was found in the riverside soil, sediment and in the biomass of aquatic plants (Bolsunovsky et al., 1999, 2002). Aquatic plants are an important link in the migration of radionuclides in an aquatic ecosystem. In laboratory experiments, we investigated accumulation of 241 Am by the submerged macrophyte from the Yenisei River: the pond weed (Elodea canadensis) and the aquatic moss (Fontinalis antipyretica), and release of 241 Am from the biomass. The content of 241 Am was measured on a Canberra (USA) gamma-spectrometer. The experiments showed that specific accumulation and concentration factors of 241 Am in the plants were in inverse proportion to their biomass. We obtained new data on release of 241 Am from the biomass of macrophyte. Americium-241 was more firmly fixed in the biomass of the aquatic moss. In 12 months, the biomass of the aquatic moss released about 30% of the initial americium activity into the water. To compare, the biomass of the pond weed released into the water medium up to 64% of the initial 241 Am activity in 1.5 4 months. The release rate was dependent on the decomposition rate of the plant biomass. The experiments showed that submerged macrophyte of the Yenisei River can accumulate considerable activities of 241 Am and retain americium for long periods of time in biomass. (author)

  6. Physics of plutonium and americium recycling in PWR using advanced fuel concepts

    International Nuclear Information System (INIS)

    Hourcade, E.

    2004-01-01

    PWR waste inventory management is considered in many countries including Frances as one of the main current issues. Pu and Am are the 2 main contents both in term of volume and long term radio-toxicity. Waiting for the Generation IV systems implementation (2035-2050), one of the mid-term solutions for their transmutation involves the use of advanced fuels in Pressurized Water Reactors (PWR). These have to require as little modification as possible of the core internals, the cooling system and fuel cycle facilities (fabrication and reprocessing). The first part of this paper deals with some neutronic characteristics of Pu and/or Am recycling. In a second part, 2 technical solutions MOX-HMR and APA-DUPLEX-84 are presented and the third part is devoted to the study of a few global strategies. The main neutronic parameters to be considered for Pu and Am recycling in PWR are void coefficient, Doppler coefficient, fraction of delayed neutrons and power distribution (especially for heterogeneous configurations). The modification of the moderation ratio, the opportunity to use inert matrices (targets), the optimisation of Uranium, Plutonium and Americium contents are the key parameters to play with. One of the solutions (APA-DUPLEX-84) presented here is a heterogeneous assembly with regular moderation ratio composed with both target fuel rods (Pu and Am embedded in an inert matrix) and standard UO 2 fuel rods. An EPR (European Pressurised Reactor) type reactor, loaded only with assemblies containing 84 peripheral targets, can reach an Americium consumption rate of (4.4; 23 kg/TWh) depending on the assembly concept. For Pu and Am inventories stabilisation, the theoretical fraction of reactors loaded with Pu + Am or Pu assemblies is about 60%. For Americium inventory stabilisation, the fraction decreases down to 16%, but Pu is produced at a rate of 18.5 Kg/TWh (-25% compared to one through UOX cycle)

  7. Separation of americium and plutonium from nuclear wastes by the TRUEX process

    International Nuclear Information System (INIS)

    Leonard, R.A.; Vandegrift, G.F.; Manry, C.W.

    1986-01-01

    Americium and plutonium can be removed from a transuranic (TRU) waste stream to <10 nCi/g by the TRUEX process. The resulting waste is nontransuranic, greatly reducing disposal costs. An overview is given of the TRUEX process and of centrifugal contactors used to implement this process. Then, a plan for the deployment of TRUEX at the Hanford Site is discussed. Finally, details are given on the proposed use of TRUEX to treat the liquid wastes from the Plutonium Finishing Plant at the Hanford Site

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

    International Nuclear Information System (INIS)

    Smith, L.L.; Markun, F.; TenKate, T.

    1992-06-01

    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

  9. Standardization of a method to study the distribution of Americium in purex process

    International Nuclear Information System (INIS)

    Dapolikar, T.T.; Pant, D.K.; Kapur, H.N.; Kumar, Rajendra; Dubey, K.

    2017-01-01

    In the present work the distribution of Americium in PUREX process is investigated in various process streams. For this purpose a method has been standardized for the determination of Am in process samples. The method involves extraction of Am with associated actinides using 30% TRPO-NPH at 0.3M HNO 3 followed by selective stripping of Am from the organic phase into aqueous phase at 6M HNO 3 . The assay of aqueous phase for Am content is carried out by alpha radiometry. The investigation has revealed that 100% Am follows the HLLW route. (author)

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

    International Nuclear Information System (INIS)

    Tanaka, Kosuke; Hirosawa, Takashi; Obayashi, Hiroshi; Koyama, Shin Ichi; Yoshimochi, Hiroshi; Tanaka, Kenya

    2008-01-01

    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

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

    International Nuclear Information System (INIS)

    Cruz, W.H.

    2013-01-01

    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 ( 241 Am), fewer and Radium 226 ( 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 241 Am radioactive lightning rods using the conventional chemical treatment method using agents and acids to break down the slides. The 241 Am recovered was as excitation source and alpha particle generator for analysing samples by X Ray Fluorescence, for fixing the stainless steel 241 Am technique was used electrodeposition. (author)

  12. Distribution coefficients for plutonium and americium on particulates in aquatic environments

    International Nuclear Information System (INIS)

    Sanchez, A.L.; Schell, W.R.; Sibley, T.H.

    1982-01-01

    The distribution coefficients of two transuranic elements, plutonium and americium, were measured experimentally in laboratory systems of selected freshwater, estuarine, and marine environments. Gamma-ray emitting isotopes of these radionuclides, 237 Pu and 241 Am, were significantly greater than the sorption Ksub(d) values, suggesting some irreversibility in the sorption of these radionuclides onto sediments. The effects of pH and of sediment concentration on the distribution coefficients were also investigated. There were significant changes in the Ksub(d) values as these parameters were varied. Experiments using sterilized and nonsterilized samples for some of the sediment/water systems indicate possible bacterial effects on Ksub(d) values. (author)

  13. Recovery of americium from slag and crucible wastes and its purification

    International Nuclear Information System (INIS)

    Michael, K.M.; Dabholkar, G.M.; Vijayan, K.; Ramamoorthy, N.; Narayanan, C.V.; Jambunathan, U.; Kapoor, S.C.

    1990-01-01

    A method of recovery and purification of americium-241 from slag waste streams is described. Extraction of Am from slag solution of 0.16 M HNO 3 was carried out by tri-n-butyl phosphate. After stripping with acetic acid, Am was precipitated at pH 1. This was followed by metathesis to remove Ca. Final separation of Pu from Am solution was achieved by anion exchange method using Dowex 1x4 anion exchange resin. Details of large scale recovery of Am from slag are also described. (author). 12 refs., 11 tabs., 1 fig

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

    International Nuclear Information System (INIS)

    Baumann, Nils; Zirnstein, Isabel; Arnold, Thuro

    2015-01-01

    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).

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

    International Nuclear Information System (INIS)

    Guillou, P.

    1990-12-01

    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

  16. Natural and anthropogenic {sup 236}U in environmental samples

    Energy Technology Data Exchange (ETDEWEB)

    Steier, Peter [VERA Laboratory, Fakultaet fuer Physik - Isotopenforschung, Universitaet Wien, Waehringer Strasse 17, A-1090 Wien (Austria)], E-mail: peter.steier@univie.ac.at; Bichler, Max [Atominstitut der Osterreichischen Universitaeten, Technische Universitaet Wien, Stadionallee 2, Wien A-1020 (Austria); Keith Fifield, L. [Department of Nuclear Physics, RSPhysSE, Australian National University, Canberra, ACT 0200 (Australia); Golser, Robin; Kutschera, Walter; Priller, Alfred [VERA Laboratory, Fakultaet fuer Physik - Isotopenforschung, Universitaet Wien, Waehringer Strasse 17, A-1090 Wien (Austria); Quinto, Francesca [Dipartimento di Scienze Ambientali, Seconda Universita di Napoli, via Vivaldi 43, Caserta 81100 (Italy); Richter, Stephan [Euopean Commission, Directorate-General Joint Research Centre, Institute for Reference Materials and Measurements (IRMM), Retieseweg 111, B-2440 Geel (Belgium); Srncik, Michaela [Institut fuer Anorganische Chemie, Universitaet Wien, Waehringer Strasse 42, A-1090 Wien (Austria); Terrasi, Philippo [Dipartimento di Scienze Ambientali, Seconda Universita di Napoli, via Vivaldi 43, Caserta 81100 (Italy); Wacker, Lukas [Institute for Particle Physics, HPK H25, Schafmattstrasse 20, CH-8093 Zuerich (Switzerland); Wallner, Anton [VERA Laboratory, Fakultaet fuer Physik - Isotopenforschung, Universitaet Wien, Waehringer Strasse 17, A-1090 Wien (Austria); Wallner, Gabriele [Institut fuer Anorganische Chemie, Universitaet Wien, Waehringer Strasse 42, A-1090 Wien (Austria); Wilcken, Klaus M. [Scottish Universities Environmental Research Centre, Scottish Enterprise Technology Park, East Kilbride G75 OQF (United Kingdom); Maria Wild, Eva [VERA Laboratory, Fakultaet fuer Physik - Isotopenforschung, Universitaet Wien, Waehringer Strasse 17, A-1090 Wien (Austria)

    2008-05-15

    The interaction of thermal neutrons with {sup 235}U results in fission with a probability of {approx}85% and in the formation of {sup 236}U (t{sub 1/2} = 2.3 x 10{sup 7} yr) with a probability of {approx}15%. While anthropogenic {sup 236}U is, therefore, present in spent nuclear fuel at levels of {sup 236}U/U up to 10{sup -2}, the expected natural ratios in the pre-anthropogenic environment range from 10{sup -14} to 10{sup -10}. At VERA, systematic investigations suggest a detection limit below {sup 236}U/U = 5 x 10{sup -12} for samples of 0.5 mg U, while chemistry blanks of {approx}2 x 10{sup 7} atoms {sup 236}U per sample limit the sensitivity for smaller samples. We have found natural isotopic ratios in uranium reagents separated before the onset of human nuclear activities, in uranium ores from various origins and in water from a subsurface well in Bad Gastein, Austria. Anthropogenic contamination was clearly visible in soil and rivulet samples from Salzburg, Austria, whereas river sediments from Garigliano river (Southern Italy) were close to the detection limit. Finally, our natural in-house standard Vienna-KkU was calibrated against a certified reference material (IRMM REIMEP-18 A)

  17. Plutonium-236 traces determination in plutonium-238 by α spectrometry

    International Nuclear Information System (INIS)

    Acena, M.L.; Pottier, R.; Berger, R.

    1969-01-01

    Two methods are described in this report for the determination of plutonium-236 traces in plutonium-238 by a spectrometry using semi-conductor detectors. The first method involves a direct comparison of the areas under the peaks of the α spectra of plutonium-236 and plutonium-238. The electrolytic preparation of the sources is carried out after preliminary purification of the plutonium. The second method makes it possible to determine the 236 Pu/ 238 Pu ratio by comparing the areas of the α peaks of uranium-232 and uranium-234, which are the decay products of the two plutonium isotopes respectively. The uranium in the source, also deposited by electrolysis, is separated from a 1 mg amount of plutonium either by a T.L.A. extraction, or by the use of ion-exchange resins. The report ends with a discussion of the results obtained with plutonium of two different origins. (authors) [fr

  18. Determination of uranium isotopic composition and {sup 236}U content of soil samples and hot particles using inductively coupled plasma mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Boulyga, S.F. [Radiation Physics and Chemistry Problems Inst., Minsk (Belarus); Becker, J.S. [Central Department for Analytical Chemistry, Research Centre Juelich (Germany)

    2001-07-01

    As a result of the accident at the Chernobyl nuclear power plant (NPP) the environment was contaminated with spent nuclear fuel. The {sup 236}U isotope was used in this study to monitor the spent uranium from nuclear fallout in soil samples collected in the vicinity of the Chernobyl NPP. Nuclear track radiography was applied for the identification and extraction of hot radioactive particles from soil samples. A rapid and sensitive analytical procedure was developed for uranium isotopic ratio measurement in environmental samples based on double-focusing inductively coupled plasma mass spectrometry (DF-ICP-MS) with a MicroMist nebulizer and a direct injection high-efficiency nebulizer (DIHEN). The performance of the DF-ICP-MS with a quartz DIHEN and plasma shielded torch was studied. Overall detection efficiencies of 4 x 10{sup -4} and 10{sup -3} counts per atom were achieved for {sup 238}U in DF-ICP-QMS with the MicroMist nebulizer and DIHEN, respectively. The rate of formation of uranium hydride ions UH{sup +}/U{sup +} was 1.2 x 10{sup -4} and 1.4 x 10{sup -4}, respectively. The precision of short-term measurements of uranium isotopic ratios (n = 5) in 1 {mu}g L{sup -1} NBS U-020 standard solution was 0.11% ({sup 238}U/{sup 235}U) and 1.4% ({sup 236}U/{sup 238}U) using a MicroMist nebulizer and 0.25% ({sup 235}U/{sup 238}U) and 1.9% ({sup 236}U/{sup 238}U) using a DIHEN. The isotopic composition of all investigated Chernobyl soil samples differed from those of natural uranium; i.e. in these samples the {sup 236}U/{sup 238}U ratio ranged from 10{sup -5} to 10{sup -3}. Results obtained with ICP-MS, {alpha}- and {gamma}-spectrometry showed differences in the migration properties of spent uranium, plutonium, and americium. The isotopic ratio of uranium was also measured in hot particles extracted from soil samples. (orig.)

  19. Production of a square geometry Americium standard source for use with photodiodes

    Energy Technology Data Exchange (ETDEWEB)

    Costa, Priscila; Geraldo, Bianca; Raele, Marcus P.; Marumo, Júlio T.; Vicente, Roberto; Zahn, Guilherme S.; Genezini, Frederico A., E-mail: priscila3.costa@usp.br, E-mail: fredzini@ipen.br [Instituto de Pesquisas Energéticas e Nucleares (IPEN/CNEN-SP), São Paulo, SP (Brazil)

    2017-07-01

    In the development of a thermal neutron detector using a square photodiode and a thin boron film, a radioactive calibration source with the same geometry was needed. An americium-243 standard source was produced by electrodeposition aiming at the calibration of a PIN-type silicon photodiode with a detection area of 10 x 10 mm{sup 2}. To produce the samples two tests were performed. In the first test, a square stainless steel plate (10 x 10 mm{sup 2}) was fixed on the surface of the conventional plate, which was removed after deposition. To reduce the loss of activity of the source, in the second test nail polish was applied on the silver plate leaving only an area of 10 x 10 mm{sup 2} without varnish coating. Once the electrodeposition process was completed, the activity concentration measurement was performed by alpha particle spectrometry. The first method presented a lower activity when compared to the total activity of Am-243 added initially. For the second method, the total activity was concentrate in the exposed square region (without nail polish). The results showed that it is possible to obtain a square geometry source; furthermore, the surrounding nail polish was not contaminated by {sup 243}Am. The comparison of these two approaches indicated that the second method was more efficient as it was possible to concentrate all the americium activity in the delimited square area. (author)

  20. Application of extraction chromatography to the recovery of neptunium, plutonium and americium from an industrial waste

    International Nuclear Information System (INIS)

    Madic, C.; Kertesz, C.; Sontag, R.; Koehly, G.

    1980-01-01

    A pilot scale investigation was made to evaluate the possible application of the extraction chromatographic method (LLC) to the partitioning of alpha emitters from liquid wastes containing traces of transuranium elements. A secondary purpose was to obtain pure Am0 2 , which is used to produce alpha, gamma, and neutron sources. The process developed for alpha partitioning consists essentially of the extraction of macro amounts of uranium with 30% TBP in dodecane in mixer-settlers, then coextraction of Np-237, Pu-239, and Am-241 by LLC on a macro column filled with di-n-hexyl-octoxy-methyl-phosphine oxide (POX.11) adsorbed on an inert support. In each run about 200 liters of initial waste are decontaminated of alpha emitters. The loading step is followed by selective elution of americium, neptunium, and plutonium. The americium eluate is then subjected to the following operations: (1) separation of Am from Fe and Cd by LLC on a TBP column and (2) separation of Am from lanthanide traces by LLC on an HD(DiBM)P column after oxidation of Am(III) to Am(VI). The Am in the eluate is subsequently reduced to Am(III) and precipitated as oxalate with oxalic acid. The oxalate is then filtered and calcined to yield pure AmO 2

  1. Fuel cycle covariance of plutonium and americium separations to repository capacity using information theoretic measures

    International Nuclear Information System (INIS)

    Scopatz, Anthony; Schneider, Erich; Li, Jun; Yim, Man-Sung

    2011-01-01

    A light water reactor, fast reactor symbiotic fuel cycle scenario was modeled and parameterized based on thirty independent inputs. Simultaneously and stochastically choosing different values for each of these inputs and performing the associated fuel cycle mass-balance calculation, the fuel cycle itself underwent Monte Carlo simulation. A novel information theoretic metric is postulated as a measure of system-wide covariance. This metric is the coefficient of variation of the set of uncertainty coefficients generated from 2D slices of a 3D contingency table. It is then applied to the fuel cycle, taking fast reactor used fuel plutonium and americium separations as independent variables and the capacity of a fully-loaded tuff repository as the response. This set of parameters is known from prior studies to have a strong covariance. When measured with all 435 other input parameters possible, the fast reactor plutonium and americium separations pair was found to be ranked the second most covariant. This verifies that the coefficient of variation metric captures the desired sensitivity of sensitivity effects in the nuclear fuel cycle. (author)

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

    International Nuclear Information System (INIS)

    Robouch, P.

    1989-01-01

    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 (CO 3 ) 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-CO 3 complexes are not needed). No evidence of Am(CO 3 ) 4 5- 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 PuO 2 (CO 3 ) is measured in bicarbonate media at high ionic strength, to obtain the solubility product and formation constants of the PuO 2 (CO 3 ) i 2-2i complexes [fr

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

    International Nuclear Information System (INIS)

    Ramsey, W.G.; Miller, D.; Minichan, R.; Coleman, L.; Schumacher, R.; Hardy, B.; Jones, R.

    1994-01-01

    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

  4. A simple approach to determine the diffusivity of americium in granite

    International Nuclear Information System (INIS)

    Song, L.; Feng, X.; Liang, J.; Zhang, Y.; Wang, J.

    2009-01-01

    The diffusivities of the key radionuclides in host rock are important for the performance assessment of repositories. One of the conventional methods for determining the diffusivities of radionuclides is to grind the rock tablet layer by layer and then to measure the radioactivity remaining on the rock tablet before each grinding cycle. Since grinding hard rock samples, especially those with radioactivity, is very difficult, we developed a new approach to determine the diffusivity of americium in granite. The new approach mainly includes two parts: one is to measure the radioactivities from both sides of a rock disk sample by autoradiography with phosphor imaging technique; the other is to study the relationship between the radioactivities and the apparent diffusivity of americium in granite by computer modelling. Because the high contamination risk of grinding radioactive rock samples has been avoided, the new approach is much simpler than the conventional method. It may be a better choice of measuring the diffusivities of radionuclides in rock, especially for those laboratories in which grinding radioactive rock samples is inconvenient. (orig.)

  5. Measurements of α-emitting plutonium and americium in the intertidal sands of west Cumbria, UK

    International Nuclear Information System (INIS)

    Eakins, J.D.; Morgan, A.; Baston, G.M.N.; Pratley, F.W.; Strange, L.P.; Burton, P.J.

    1990-01-01

    Samples of surface sand and sand cores were collected from intertidal regions of west Cumbria between Silloth and Walney Island (including the Duddon Estuary) between 1982 and 1984 and analysed for 238 Pu, 239+240 Pu and 241 Am. Generally, more than 95% of the α-emitting transuranic nuclides were associated with the sand and less than 5% with entrained silt. The greatest concentrations of both plutonium and americium were found at Braystones. Concentrations declined with distance from the Sellafield Works. The largest actinide deposits occurred at Drigg (320 and 720 kBq m -2 of 239+240 Pu and 241 Am respectively). The integrated deposits in intertidal sand between Silloth and Walney Island were about 4.2 and 7.0 TBq respectively, which represent about 1% of the total α-emitting activity discharged to sea from Sellafield Works up to 1982. The corresponding value for the Duddon Estuary is about 0.3%. Only on beaches close to Sellafield did levels of man-made α-emitters exceed those of natural α-emitting nuclides. The radiological consequences of the intertidal inventory of plutonium and americium are shown to be very small and much less than from the seafood pathway. (author)

  6. Measurements of. alpha. -emitting plutonium and americium in the intertidal sands of west Cumbria, UK

    Energy Technology Data Exchange (ETDEWEB)

    Eakins, J.D.; Morgan, A.; Baston, G.M.N.; Pratley, F.W.; Strange, L.P.; Burton, P.J. (UKAEA Harwell Lab. (UK). Environmental and Medical Science Div.)

    1990-01-01

    Samples of surface sand and sand cores were collected from intertidal regions of west Cumbria between Silloth and Walney Island (including the Duddon Estuary) between 1982 and 1984 and analysed for {sup 238}Pu, {sup 239+240}Pu and {sup 241}Am. Generally, more than 95% of the {alpha}-emitting transuranic nuclides were associated with the sand and less than 5% with entrained silt. The greatest concentrations of both plutonium and americium were found at Braystones. Concentrations declined with distance from the Sellafield Works. The largest actinide deposits occurred at Drigg (320 and 720 kBq m{sup -2} of {sup 239+240}Pu and {sup 241}Am respectively). The integrated deposits in intertidal sand between Silloth and Walney Island were about 4.2 and 7.0 TBq respectively, which represent about 1% of the total {alpha}-emitting activity discharged to sea from Sellafield Works up to 1982. The corresponding value for the Duddon Estuary is about 0.3%. Only on beaches close to Sellafield did levels of man-made {alpha}-emitters exceed those of natural {alpha}-emitting nuclides. The radiological consequences of the intertidal inventory of plutonium and americium are shown to be very small and much less than from the seafood pathway. (author).

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

    Energy Technology Data Exchange (ETDEWEB)

    Raison, P.E. [CEA Cadarache, 13 - Saint-Paul-lez-Durance (France). Dept. d' Etudes des Combustibles; Haire, R.G. [Oak Ridge National Lab., TN (United States)

    2001-07-01

    Presented are studies involving the incorporation of americium and curium in zirconia-based materials. First explored was the pseudo ternary system AmO{sub 2}-ZrO{sub 2}-Y{sub 2}O{sub 3}. 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 AmO{sub 2} content. The Cm{sub 2}O{sub 3}-ZrO{sub 2} system was also investigated. It was found that at 25 mol% of CmO{sub 1.5}, 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 CmO{sub 1.5}, a pyrochlore oxide - Cm{sub 2}Zr{sub 2}O{sub 7} - is formed (a = 10.63 {+-}0.02 Angstrom). (author)

  8. Comparison of Americium-Beryllium neutron spectrum obtained using activation foil detectors and NE-213 spectrometer

    International Nuclear Information System (INIS)

    Sunny, Sunil; Subbaiah, K.V.; Selvakumaran, T.S.

    1999-01-01

    Neutron spectrum of Americium - Beryllium (α,n) source is measured with two different spectrometers vis-a-vis activation foils (foil detectors) and NE-213 organic scintillator. Activity induced in the foils is measured with 4π-β-γ sodium iodide detector by integrating counts under photo peak and the saturation activity is found by correcting to elapsed time before counting. The data on calculated activity is fed into the unfolding code, SAND-II to obtain neutron spectrum. In the case of organic scintillator, the pulse height spectrum is obtained using MCA and this is processed with unfolding code DUST in order to get neutron spectrum. The Americium - Beryllium (α,n) neutron spectrum thus obtained by two different methods is compared. It is inferred that the NE-213 scintillator spectrum is in excellent agreement with the values beyond 1MeV. Neutron spectrum obtained by activation foils depends on initial guess spectrum and is found to be in reasonable agreement with NE-213 spectrum. (author)

  9. Buildup of 236U in the gaseous diffusion plant product

    International Nuclear Information System (INIS)

    Ford, J.S.

    1975-01-01

    A generalized projection of the average annual 236 U concentration that can be expected in future enriched uranium product from the US-ERDA gaseous diffusion plants when reprocessed fuels become available for cascade feeding is given. It is concluded that the buildup of 236 U is not an ever-increasing function, but approaches a limiting value. Projected concentrations result in only slight separative work losses and present no operational problem to ERDA in supplying light water reactor requirements. The use of recycle uranium from power reactor spent fuels will result in significant savings in natural uranium feed

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

    International Nuclear Information System (INIS)

    Lopez, M. A.; Broggio, D.; Capello, K.; Cardenas-Mendez, E.; El-Faramawy, N.; Franck, D.; James, A. C.; Kramer, G. H.; Lacerenza, G.; Lynch, T. P.; Navarro, J. F.; Navarro, T.; Perez, B.; Ruehm, W.; Tolmachev, S. Y.; Weitzenegger, E.

    2011-01-01

    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)

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

    International Nuclear Information System (INIS)

    Rodwell, P.; Stather, J.W.

    1978-01-01

    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.)

  12. The weak acid resin process: a dustless conversion route for the synthesis of americium bearing-blanket precursors

    International Nuclear Information System (INIS)

    Picart, S.; Gauthe, A.; Parant, P.; Remy, E.; Jobelin, I.; Pomared, J.M.; Grangaud, P.; Dauby, J.; Delahaye, T.; Caisso, M.; Bataille, M.; Bayle, J.P.; Frost, C.; Delage, C.; Martin, C.L.; Ayral, E.

    2016-01-01

    Mixed uranium-americium oxides are one of the materials envisaged for Americium Bearing Blankets dedicated to transmutation in fast neutron reactors. Conversion and fabrication processes are currently developed to make those materials in the form of dense and homogeneous oxide ceramic pellets or dense granulates incorporating uranium and americium. Their development points out the need of a simplified and optimized process which could lower hazards linked to dust generation of highly contaminating and irradiating compounds and facilitate material transfer in remote handling operations. This reason motivated the development of innovative 'dustless' route such as the Weak Acid Resin route (WAR) which provides the oxide precursors in the form of sub-millimeter-sized microspheres with optimal flowability and limits dust generation during conversion and fabrication steps. This study is thus devoted to the synthesis of mixed uranium-americium oxide microspheres by the WAR process and to the characterization of such precursors. This work also deals with their application to the fabrication of dense or porous pellets and with their potential use as dense spherules to make Sphere-Pac fuel. (authors)

  13. On the influence of the americium isotopic vector on the cooling time of minor actinides bearing blankets in fast reactors

    Directory of Open Access Journals (Sweden)

    Kooyman Timothée

    2018-01-01

    Full Text Available In the heterogeneous minor actinides transmutation approach, the nuclei to be transmuted are loaded in dedicated targets often located at the core periphery, so that long-lived heavy nuclides are turned into shorter-lived fission products by fission. To compensate for low flux level at the core periphery, the minor actinides content in the targets is set relatively high (around 20 at.%, which has a negative impact on the reprocessing of the targets due to their important decay heat level. After a complete analysis of the main contributors to the heat load of the irradiated targets, it is shown here that the choice of the reprocessing order of the various feeds of americium from the fuel cycle depends on the actual limit for fuel reprocessing. If reprocessing of hot targets is possible, it is more interesting to reprocess first the americium feed with a high 243Am content in order to limit the total cooling time of the targets, while if reprocessing of targets is limited by their decay heat, it is more interesting to wait for an increase in the 241Am content before loading the americium in the core. An optimization of the reprocessing order appears to lead to a decrease of the total cooling time by 15 years compared to a situation where all the americium feeds are mixed together when two feeds from SFR are considered with a high reprocessing limit.

  14. The weak acid resin process: a dustless conversion route for the synthesis of americium bearing-blanket precursors

    Energy Technology Data Exchange (ETDEWEB)

    Picart, S.; Gauthe, A.; Parant, P.; Remy, E.; Jobelin, I.; Pomared, J.M.; Grangaud, P.; Dauby, J.; Delahaye, T. [CEA, Centre de Marcoule, DEN/MAR/DRCP, F-30207 Bagnols-sur-Ceze (France); Caisso, M.; Bataille, M.; Bayle, J.P. [CEA, Centre de Marcoule, DEN/MAR/DTEC, F-30207 Bagnols-sur-Ceze (France); Frost, C. [CEA, Centre de Marcoule, DEN/MAR/DRCP, F-30207 Bagnols-sur-Ceze (France); Institut Europeen des Membranes, CNRS-ENSCM-UM, CC47, University of Montpellier, F-34095 Montpellier (France); Delage, C. [CEA, Centre de Cadarache, DEN/CAD/DEC, Saint-Paul-lez-Durance (France); Martin, C.L. [Univ. Grenoble Alpes, CNRS, SIMAP, F-38000 Grenoble (France); Ayral, E. [Institut Europeen des Membranes, CNRS-ENSCM-UM, CC47, University of Montpellier, F-34095 Montpellier (France)

    2016-07-01

    Mixed uranium-americium oxides are one of the materials envisaged for Americium Bearing Blankets dedicated to transmutation in fast neutron reactors. Conversion and fabrication processes are currently developed to make those materials in the form of dense and homogeneous oxide ceramic pellets or dense granulates incorporating uranium and americium. Their development points out the need of a simplified and optimized process which could lower hazards linked to dust generation of highly contaminating and irradiating compounds and facilitate material transfer in remote handling operations. This reason motivated the development of innovative 'dustless' route such as the Weak Acid Resin route (WAR) which provides the oxide precursors in the form of sub-millimeter-sized microspheres with optimal flowability and limits dust generation during conversion and fabrication steps. This study is thus devoted to the synthesis of mixed uranium-americium oxide microspheres by the WAR process and to the characterization of such precursors. This work also deals with their application to the fabrication of dense or porous pellets and with their potential use as dense spherules to make Sphere-Pac fuel. (authors)

  15. 48 CFR 52.236-17 - Layout of Work.

    Science.gov (United States)

    2010-10-01

    ... 48 Federal Acquisition Regulations System 2 2010-10-01 2010-10-01 false Layout of Work. 52.236-17... Layout of Work. As prescribed in 36.517, insert the following clause in solicitations and contracts when... need for accurate work layout and for siting verification during work performance: Layout of Work (APR...

  16. 27 CFR 46.236 - Articles in a warehouse.

    Science.gov (United States)

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 2 2010-04-01 2010-04-01 false Articles in a warehouse... Tubes Held for Sale on April 1, 2009 Filing Requirements § 46.236 Articles in a warehouse. (a) Articles... articles will be offered for sale. (b) Articles offered for sale at several locations must be reported on a...

  17. 49 CFR 236.51 - Track circuit requirements.

    Science.gov (United States)

    2010-10-01

    ...: All Systems Track Circuits § 236.51 Track circuit requirements. Track relay controlling home signals shall be in deenergized position, or device that functions as a track relay controlling home signals... conditions exist: (a) When a rail is broken or a rail or switch-frog is removed except when a rail is broken...

  18. 48 CFR 552.236-74 - Working Hours.

    Science.gov (United States)

    2010-10-01

    ... 48 Federal Acquisition Regulations System 4 2010-10-01 2010-10-01 false Working Hours. 552.236-74... Hours. As prescribed in 536.570-5, insert the following clause: Working Hours (APR 1984) (a) It is contemplated that all work will be performed during the customary working hours of the trades involved unless...

  19. 49 CFR 236.919 - Operations and Maintenance Manual.

    Science.gov (United States)

    2010-10-01

    ..., INSPECTION, MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Standards for Processor-Based Signal and Train Control Systems § 236.919 Operations and Maintenance Manual. (a... identify all software versions, revisions, and revision dates. Plans must be legible and correct. (c...

  20. 49 CFR 236.1039 - Operations and Maintenance Manual.

    Science.gov (United States)

    2010-10-01

    ..., INSPECTION, MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Positive Train Control Systems § 236.1039 Operations and Maintenance Manual. (a) The railroad shall catalog and... software versions, revisions, and revision dates. Plans must be legible and correct. (c) Hardware, software...

  1. 48 CFR 52.236-13 - Accident Prevention.

    Science.gov (United States)

    2010-10-01

    ... 48 Federal Acquisition Regulations System 2 2010-10-01 2010-10-01 false Accident Prevention. 52....236-13 Accident Prevention. As prescribed in 36.513, insert the following clause: Accident Prevention... contracts for construction or dismantling, demolition, or removal of improvements, the Contractor shall— (1...

  2. Mass and abundance {sup 236}U sensitivities at CIRCE

    Energy Technology Data Exchange (ETDEWEB)

    De Cesare, M., E-mail: m.decesare@cira.it [Department of Nuclear Physics, Research School of Physics and Engineering, Australian National University, ACT 0200 Canberra (Australia); CIRCE and Dipartimento di Matematica e Fisica, Seconda Universitá di Napoli, via Vivaldi 43, 81100 Caserta (Italy); De Cesare, N.; D’Onofrio, A. [CIRCE and Dipartimento di Matematica e Fisica, Seconda Universitá di Napoli, via Vivaldi 43, 81100 Caserta (Italy); INFN Sezione di Napoli, via Cintia, Edificio G, 80126 Napoli (Italy); Fifield, L.K. [Department of Nuclear Physics, Research School of Physics and Engineering, Australian National University, ACT 0200 Canberra (Australia); Gialanella, L.; Terrasi, F. [CIRCE and Dipartimento di Matematica e Fisica, Seconda Universitá di Napoli, via Vivaldi 43, 81100 Caserta (Italy); INFN Sezione di Napoli, via Cintia, Edificio G, 80126 Napoli (Italy)

    2015-10-15

    The actinides (e.g. {sup 236}U and {sup x}Pu isotopes) are present in environmental samples at the ultra trace level since atmospheric tests of NWs (Nuclear Weapons) performed in the past, deliberate dumping of nuclear waste, nuclear fuel reprocessing, on a large scale and operation of NPPs (Nuclear Power Plants) on a small scale have led to the release of a wide range of radioactive nuclides in the environment. Their detection requires the most sensitive AMS (Accelerator Mass Spectrometry) techniques and at the Center for Isotopic Research on Cultural and Environmental heritage (CIRCE) in Caserta, Italy, an upgraded actinide AMS system, based on a 3-MV pelletron tandem accelerator, has been operated. In this paper the progress made in order to push the {sup 236}U mass sensitivity and {sup 236}U/{sup 238}U isotopic ratio down to the natural levels is reported. A uranium contamination mass of about 0.05 μg and a {sup 236}U/{sup 238}U isotopic ratio sensitivities at the level of 3.2 × 10{sup −13} are presently achievable.

  3. Mass and abundance 236U sensitivities at CIRCE

    Science.gov (United States)

    De Cesare, M.; De Cesare, N.; D'Onofrio, A.; Fifield, L. K.; Gialanella, L.; Terrasi, F.

    2015-10-01

    The actinides (e.g. 236U and xPu isotopes) are present in environmental samples at the ultra trace level since atmospheric tests of NWs (Nuclear Weapons) performed in the past, deliberate dumping of nuclear waste, nuclear fuel reprocessing, on a large scale and operation of NPPs (Nuclear Power Plants) on a small scale have led to the release of a wide range of radioactive nuclides in the environment. Their detection requires the most sensitive AMS (Accelerator Mass Spectrometry) techniques and at the Center for Isotopic Research on Cultural and Environmental heritage (CIRCE) in Caserta, Italy, an upgraded actinide AMS system, based on a 3-MV pelletron tandem accelerator, has been operated. In this paper the progress made in order to push the 236U mass sensitivity and 236U/238U isotopic ratio down to the natural levels is reported. A uranium contamination mass of about 0.05 μg and a 236U/238U isotopic ratio sensitivities at the level of 3.2 × 10-13 are presently achievable.

  4. 27 CFR 40.236 - Release from customs custody.

    Science.gov (United States)

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 2 2010-04-01 2010-04-01 false Release from customs... on Tobacco Products § 40.236 Release from customs custody. The release of tobacco products from customs custody, in bond, for transfer to the premises of a tobacco products factory, shall be in...

  5. 48 CFR 1852.236-73 - Hurricane plan.

    Science.gov (United States)

    2010-10-01

    ... 48 Federal Acquisition Regulations System 6 2010-10-01 2010-10-01 true Hurricane plan. 1852.236-73... Hurricane plan. As prescribed in 1836.570(c), insert the following clause: Hurricane Plan (DEC 1988) In the event of a hurricane warning, the Contractor shall— (a) Inspect the area and place all materials...

  6. 48 CFR 852.236-74 - Inspection of construction.

    Science.gov (United States)

    2010-10-01

    ...: (a) Inspection of materials and articles furnished under this contract will be made at the site by... 48 Federal Acquisition Regulations System 5 2010-10-01 2010-10-01 false Inspection of construction... CLAUSES AND FORMS SOLICITATION PROVISIONS AND CONTRACT CLAUSES Texts of Provisions and Clauses 852.236-74...

  7. 24 CFR 236.253 - Premiums-operating loss loans.

    Science.gov (United States)

    2010-04-01

    ... Obligations for Mortgage Insurance § 236.253 Premiums—operating loss loans. All of the provisions of § 207.252a of this chapter relating to mortgage insurance premiums on operating loss loans shall apply to... Act the mortgage insurance premiums due in accordance with § 207.252a shall be calculated on the basis...

  8. 48 CFR 53.236 - Construction and architect-engineer contracts.

    Science.gov (United States)

    2010-10-01

    ... 48 Federal Acquisition Regulations System 2 2010-10-01 2010-10-01 false Construction and architect-engineer contracts. 53.236 Section 53.236 Federal Acquisition Regulations System FEDERAL ACQUISITION...-engineer contracts. ...

  9. 49 CFR 236.338 - Mechanical locking required in accordance with locking sheet and dog chart.

    Science.gov (United States)

    2010-10-01

    ... locking sheet and dog chart. 236.338 Section 236.338 Transportation Other Regulations Relating to... in accordance with locking sheet and dog chart. Mechanical locking shall be in accordance with locking sheet and dog chart currently in effect. ...

  10. Worldwide bioassay data resources for plutonium/americium internal dosimetry studies

    International Nuclear Information System (INIS)

    Miller, G.; Bertelli, L.; Little, T.; Guilmette, R.; Riddell, T.; Filipy, R.

    2005-01-01

    Full text: Biokinetic models are the scientific underpinning of internal dosimetry. These models describe how materials of interest taken into the body by various routes (for example inhalation) are transported through the body, allowing the modelling of bioassay measurements and the estimation of radiation dose. The International Commission on Radiation Protection (ICRP) publishes biokinetic models for use in internal dosimetry. These models represent the consensus judgement of a committee of experts, based on human and animal data. Nonetheless, it is important to validate biokinetic models using directly applicable data, in a scientifically transparent manner, especially for internal dosimetry research purposes (as opposed to radiation protection), as in epidemiology studies. Two major goals would be to determine individual variations of model parameters for the purpose of assessing this source of uncertainty in internal dose calculations, and to determine values of workplace specific parameters (such as particle solubility in lung fluids) for different representative workplaces. Furthermore, data on the observed frequency of intakes under various conditions can be used in the interpretation of bioassay data. All of the above may be couched in the terminology of Bayesian statistical analysis and amount to the determination of the Bayesian prior probability distributions needed in a Bayesian interpretation of bioassay data. The authors have direct knowledge of several significant databases of plutonium/americium bioassay data (including autopsy data). The purpose of this paper is to acquaint the worldwide community with these resources and to invite others who may know of other such databases to participate with us in a publication that would document the content, form, and the procedures for seeking access to these databases. These databases represent a tremendous scientific resource in this field. Examples of databases known to the authors include: the

  11. XRD monitoring of α self-irradiation in uranium-americium mixed oxides.

    Science.gov (United States)

    Horlait, Denis; Lebreton, Florent; Roussel, Pascal; Delahaye, Thibaud

    2013-12-16

    The structural evolution under (241)Am self-irradiation of U(1-x)Am(x)O(2±δ) transmutation fuels (with x ≤ 0.5) was studied by X-ray diffraction (XRD). Samples first underwent a preliminary heat treatment performed under a reducing atmosphere (Ar/H2(4%)) aiming to recover the previously accumulated structural defects. Over all measurements (carried out over up to a full year and for integrated doses up to 1.5 × 10(18) α-decay events·g(-1)), only fluorite U(1-x)Am(x)O(2±δ) solid solutions were observed. Within a few days after the end of the heat treatment, each of the five studied samples was slowly oxidized as a consequence of their move to air atmosphere, which is evidenced by XRD by an initial sharp decrease of the unit cell parameter. For the compounds with x ≤ 0.15, this oxidation occurred without any phase transitions, but for U0.6Am0.4O(2±δ) and U0.5Am0.5O(2±δ), this process is accompanied by a transition from a first fluorite solid solution to a second oxidized one, as the latter is thermodynamically stable in ambient conditions. In the meantime and after the oxidation process, (241)Am α self-irradiation caused a structural swelling up to ∼0.8 vol %, independently of the sample composition. The kinetic constants of swelling were also determined by regression of experimental data and are, as expected, dependent on x and thus on the dose rate. The normalization of these kinetic constants by sample α-activity, however, leads to very close swelling rates among the samples. Finally, evolutions of microstrain and crystallite size were also monitored, but for the considered dose rates and cumulated doses, α self-irradiation was found, within the limits of the diffractometer used, to have almost no impact on these characteristics. Microstrain was found to be influenced instead by the americium content in the materials (i.e., by the impurities associated with americium starting material and the increase of cationic charge heterogeneity with

  12. 48 CFR 452.236-74 - Control of Erosion, Sedimentation, and Pollution.

    Science.gov (United States)

    2010-10-01

    ..., Sedimentation, and Pollution. 452.236-74 Section 452.236-74 Federal Acquisition Regulations System DEPARTMENT OF....236-74 Control of Erosion, Sedimentation, and Pollution. As prescribed in 436.574, insert the following clause: Control of Erosion, Sedimentation, and Pollution (NOV 1996) (a) Operations shall be...

  13. 33 CFR 2.36 - Navigable waters of the United States, navigable waters, and territorial waters.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Navigable waters of the United States, navigable waters, and territorial waters. 2.36 Section 2.36 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY GENERAL JURISDICTION Jurisdictional Terms § 2.36 Navigable waters...

  14. 49 CFR 236.312 - Movable bridge, interlocking of signal appliances with bridge devices.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Movable bridge, interlocking of signal appliances with bridge devices. 236.312 Section 236.312 Transportation Other Regulations Relating to... SYSTEMS, DEVICES, AND APPLIANCES Interlocking Standards § 236.312 Movable bridge, interlocking of signal...

  15. 48 CFR 52.236-23 - Responsibility of the Architect-Engineer Contractor.

    Science.gov (United States)

    2010-10-01

    ... Architect-Engineer Contractor. 52.236-23 Section 52.236-23 Federal Acquisition Regulations System FEDERAL... Provisions and Clauses 52.236-23 Responsibility of the Architect-Engineer Contractor. As prescribed in 36.609-2(b), insert the following clause: Responsibility of the Architect-Engineer Contractor (APR 1984) (a...

  16. 48 CFR 236.602 - Selection of firms for architect-engineer contracts.

    Science.gov (United States)

    2010-10-01

    ... 48 Federal Acquisition Regulations System 3 2010-10-01 2010-10-01 false Selection of firms for architect-engineer contracts. 236.602 Section 236.602 Federal Acquisition Regulations System DEFENSE... ARCHITECT-ENGINEER CONTRACTS Architect-Engineer Services 236.602 Selection of firms for architect-engineer...

  17. 48 CFR 952.236-71 - Inspection in architect-engineer contracts.

    Science.gov (United States)

    2010-10-01

    ... 48 Federal Acquisition Regulations System 5 2010-10-01 2010-10-01 false Inspection in architect-engineer contracts. 952.236-71 Section 952.236-71 Federal Acquisition Regulations System DEPARTMENT OF....236-71 Inspection in architect-engineer contracts. As prescribed at 936.609-3 insert the following...

  18. 48 CFR 853.236 - Construction and architect-engineer contracts.

    Science.gov (United States)

    2010-10-01

    ... 48 Federal Acquisition Regulations System 5 2010-10-01 2010-10-01 false Construction and architect-engineer contracts. 853.236 Section 853.236 Federal Acquisition Regulations System DEPARTMENT OF VETERANS AFFAIRS CLAUSES AND FORMS FORMS Prescription of Forms 853.236 Construction and architect-engineer...

  19. 48 CFR 52.236-24 - Work Oversight in Architect-Engineer Contracts.

    Science.gov (United States)

    2010-10-01

    ... Architect-Engineer Contracts. 52.236-24 Section 52.236-24 Federal Acquisition Regulations System FEDERAL... Provisions and Clauses 52.236-24 Work Oversight in Architect-Engineer Contracts. As prescribed in 36.609-3, insert the following clause: Work Oversight in Architect-Engineer Contracts (APR 1984) The extent and...

  20. 49 CFR 236.330 - Locking dog of switch-and-lock movement.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Locking dog of switch-and-lock movement. 236.330 Section 236.330 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD... Rules and Instructions § 236.330 Locking dog of switch-and-lock movement. Locking dog of switch-and-lock...

  1. 29 CFR 1952.236 - Where the plan may be inspected.

    Science.gov (United States)

    2010-07-01

    ... and copied during normal business hours at the following locations: Office of State Programs... 29 Labor 9 2010-07-01 2010-07-01 false Where the plan may be inspected. 1952.236 Section 1952.236..., DEPARTMENT OF LABOR (CONTINUED) APPROVED STATE PLANS FOR ENFORCEMENT OF STATE STANDARDS Kentucky § 1952.236...

  2. 24 CFR 236.755 - Housing owner's obligation under contract to report tenant income increase.

    Science.gov (United States)

    2010-04-01

    ... FOR RENTAL PROJECTS Rental Assistance Payments § 236.755 Housing owner's obligation under contract to... 24 Housing and Urban Development 2 2010-04-01 2010-04-01 false Housing owner's obligation under contract to report tenant income increase. 236.755 Section 236.755 Housing and Urban Development...

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

    International Nuclear Information System (INIS)

    Popplewell, D.S.; Ham, G.J.; Johnson, T.E.

    1984-01-01

    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.)

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

    International Nuclear Information System (INIS)

    Hamilton, T.F.; Smith, J.D.

    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 241 Am was low, with specific activity in the tissues 241 Am occurred and 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)

  5. 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

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

    International Nuclear Information System (INIS)

    Testa, C.; Desideri, D.; Meli, M.A.; Guerra, F.; Degetto, S.; Jia, G.; Gerdol, R.

    1998-01-01

    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 210 Pb method. A typical peak for 239,240 Pu and 241 Am 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 239,240 Pu and 238 Pu. (author)

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

    International Nuclear Information System (INIS)

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

    2013-01-01

    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)

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

    International Nuclear Information System (INIS)

    Melanie Mueller; Margret Acker; Steffen Taut; Gert Bernhard; Forschungszentrum Dresden-Rossendorf, Dresden

    2010-01-01

    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 NaClO 4 , 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 β 110 = 2.56 ± 0.08 and log β 120 = 3.93 ± 0.19. (author)

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

    International Nuclear Information System (INIS)

    Reichley-Yinger, L.; Vandegrift, G.F.

    1987-01-01

    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 NaClO 2 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

  10. Americium-241 in surface soil associated with the Hanford site and vicinity

    International Nuclear Information System (INIS)

    Price, K.R.; Gilbert, R.O.; Gano, K.A.

    1981-05-01

    Various kinds of surface soil samples were collected and analyzed for Americium-241 ( 241 Am) to examine the feasibility of improving soil sample data for the Hanford Surface Environmental Surveillance Program. Results do not indicate that a major improvement would occur if procedures were changed from the current practices. Conclusions from this study are somewhat tempered by the very low levels of 241 Am ( 241 Am in soil crust (0 to 1.0 cm deep) was greater than the corresponding subsurface layer (1.0 to 2.5 cm deep), and the average concentration of 241 Am in some onsite samples collected near the PUREX facility was greater than comparable samples collected 60 km upwind at an offsite location

  11. Separation and measurement of thorium, plutonium, americium, uranium and strontium in environmental matrices

    International Nuclear Information System (INIS)

    Harrison, Jennifer J.; Zawadzki, Atun; Chisari, Robert; Wong, Henri K.Y.

    2011-01-01

    A technique for the isolation of thorium (Th), plutonium (Pu), americium (Am), uranium (U) and strontium (Sr) isotopes from various environmental matrices has been adapted from a previously published method specific to water samples (). Separation and isolation of the various elemental fractions from a single sub-sample is possible, thereby eliminating the need for multiple analyses. The technique involves sample dissolution, concentration via calcium phosphate co-precipitation, rapid column extraction using TEVA TM , TRU TM and Sr-Spec TM resin cartridges, alpha spectrometry for Th, Pu, U and Am and Cerenkov counting for Sr. Various standard reference materials were analysed and chemical yields are in the range of 70-80% for Th, Am, U and Sr and 50-60% for Pu. Sample sizes of up to 10 L for water, 5 g for dry soil and sediment and 10 g for dry vegetation and seaweed can be processed using this technique.

  12. Separation and measurement of thorium, plutonium, americium, uranium and strontium in environmental matrices

    Energy Technology Data Exchange (ETDEWEB)

    Harrison, Jennifer J., E-mail: jennifer.harrison@ansto.gov.au [Australian Nuclear Science and Technology Organisation, PMB 1, Menai NSW 2234 (Australia); Zawadzki, Atun; Chisari, Robert; Wong, Henri K.Y. [Australian Nuclear Science and Technology Organisation, PMB 1, Menai NSW 2234 (Australia)

    2011-10-15

    A technique for the isolation of thorium (Th), plutonium (Pu), americium (Am), uranium (U) and strontium (Sr) isotopes from various environmental matrices has been adapted from a previously published method specific to water samples (). Separation and isolation of the various elemental fractions from a single sub-sample is possible, thereby eliminating the need for multiple analyses. The technique involves sample dissolution, concentration via calcium phosphate co-precipitation, rapid column extraction using TEVA{sup TM}, TRU{sup TM} and Sr-Spec{sup TM} resin cartridges, alpha spectrometry for Th, Pu, U and Am and Cerenkov counting for Sr. Various standard reference materials were analysed and chemical yields are in the range of 70-80% for Th, Am, U and Sr and 50-60% for Pu. Sample sizes of up to 10 L for water, 5 g for dry soil and sediment and 10 g for dry vegetation and seaweed can be processed using this technique.

  13. Liquid-liquid extraction of plutonium and americium by cekanoic acid from alkaline medium

    International Nuclear Information System (INIS)

    Venugopal Chetty, K.; Sagar, V.; Swarup, R.

    2001-01-01

    Liquid-liquid extraction studies of plutonium and americium from aqueous carbonate medium using a high molecular weight carboxylic acid namely cekanoic acid in different diluents has been carried out. The distribution ratio (D) values for Pu(IV) and Am(III) under various parameters such as concentration of extractant, Na 2 CO 3 and initial pH were obtained. Results indicated that Pu(IV) and Am(III) could be satisfactorily extracted together or individually from aqueous carbonate medium using cekanoic acid in different diluents like carbon tetrachloride, cyclohexane, toluene, n-dodecane or solvesso-100. The D values for Pu(IV) and Am(III) also indicated the possibility of their mutual separation. The back extraction of Pu and Am with different reagents was also studied. (orig.)

  14. Magnesium ionophore II as an extraction agent for trivalent europium and americium

    Energy Technology Data Exchange (ETDEWEB)

    Makrlik, Emanuel [Czech Univ. of Life Sciences, Prague (Czech Republic). Faculty of Environmental Sciences; Vanura, Petr [Univ. of Chemistry and Technology, Prague (Czech Republic). Dept. of Analytical Chemistry

    2016-11-01

    Solvent extraction of microamounts of trivalent europium and americium into nitrobenzene by using a mixture of hydrogen dicarbollylcobaltate (H{sup +}B{sup -}) and magnesium ionophore II (L) was studied. The equilibrium data were explained assuming that the species HL{sup +}, HL{sup +}{sub 2}, ML{sup 3+}{sub 2}, and ML{sup 3+}{sub 3} (M{sup 3+} = Eu{sup 3+}, Am{sup 3+}; L=magnesium, ionophore II) are extracted into the nitrobenzene phase. Extraction and stability constants of the cationic complex species in nitrobenzene saturated with water were determined and discussed. From the experimental results it is evident that this effective magnesium ionophore II receptor for the Eu{sup 3+} and Am{sup 3+} cations could be considered as a potential extraction agent for nuclear waste treatment.

  15. Shape Isomer in 236U Populated by Thermal Neutron Capture

    DEFF Research Database (Denmark)

    Andersen, Verner; Christensen, Carl Jørgen; Borggreen, J.

    1976-01-01

    The 116 ns shape isomer in 236U was populated by thermal neutron capture. Conversion electrons and X-rays were detected simultaneously in delayed coincidence with fission. The ratio of delayed to prompt fission was measured with the result, σIIf/σf = (1.0±0.2) × 10−5. A branching of the isomeric ...... decay σIIγ/σIIf = 7±2 was deduced from this number. No definite electron line structure was observed....

  16. Update neutron nuclear data evaluation for 236,238Np

    International Nuclear Information System (INIS)

    Chen, Guochang; Wang, Jimin; Yu, Baosheng; Cao, Wentian; Tang, Guo-you

    2015-01-01

    The nuclear data with high accuracy for actinides play an important role in nuclear technology applications, including reactor design and operation, fuel cycle, estimation of the amount of minor actinides (MAs) in high burnup reactors and to research to transmute the MAs to short half-lived nuclides or stable ones. The nuclides of 236 Np are generated via the α-decay of 240 Am or 237 Np(n, 2n) and 237 Np(d, t) reactions. And the nuclides of 238 Np are generated via the α-decay of 242 Am or 237 Np(n, γ) and 237 Np(d, p) reactions. In the present work, according to the systematic trend of the total cross section and elastic cross section etc. of different Np isotopes, and based on the neutron optical model parameters (OMP) of 237 Np, a new set of neutron optical model parameters were obtained for 236,238 Np. Based on the new set OMP and the systematic trend of the cross sections of different Np isotopes, a full set of 236,238 Np neutron nuclear data has been updated and improved by theoretical calculation. The present result has significant improvements over the data in CENDL-3.1

  17. 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)

    Miramand, P.

    1984-06-01

    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 [fr

  18. Annual report for FY 1976 on project AN0115A: the migration of plutonium and americium in the lithosphere

    International Nuclear Information System (INIS)

    Fried, S.; Friedman, A.M.; Hines, J.J.; Atcher, R.W.; Quarterman, L.A.; Volesky, A.

    1976-12-01

    Studies have been carried out on the migration of plutonium and americium in solutions flowing through porous and crushed rock and through fissures. The migration process can be described in terms of the surface absorption of these elements. In addition, chemical effects on the absorption have been observed. One of these effects is possibly due to the presence of a plutonium polymer that migrates at a more rapid rate than normal plutonium

  19. Upper limits to americium concentration in large sized sodium-cooled fast reactors loaded with metallic fuel

    International Nuclear Information System (INIS)

    Zhang, Youpeng; Wallenius, Janne

    2014-01-01

    Highlights: • The americium transmutation capability of Integral Fast Reactor was investigated. • The impact from americium introduction was parameterized by applying SERPENT Monte Carlo calculations. • Higher americium content in metallic fuel leads to a power penalty, preserving consistent safety margins. - Abstract: Transient analysis of a large sized sodium-cooled reactor loaded with metallic fuel modified by different fractions of americium have been performed. Unprotected loss-of-offsite power, unprotected loss-of-flow and unprotected transient-over-power accidents were simulated with the SAS4A/SASSYS code based on the geometrical model of an IFR with power rating of 2500 MW th , using safety parameters obtained with the SERPENT Monte Carlo code. The Ti-modified austenitic D9 steel, having higher creep rupture strength, was considered as the cladding and structural material apart from the ferritic/martensitic HT9 steel. For the reference case of U–12Pu–1Am–10Zr fuel at EOEC, the margin to fuel melt during a design basis condition UTOP is about 50 K for a maximum linear rating of 30 kW/m. In order to maintain a margin of 50 K to fuel failure, the linear power rating has to be reduced by ∼3% and 6% for 2 wt.% and 3 wt.% Am introduction into the fuel respectively. Hence, an Am concentration of 2–3 wt.% in the fuel would lead to a power penalty of 3–6%, permitting a consumption rate of 3.0–5.1 kg Am/TW h th . This consumption rate is significantly higher than the one previously obtained for oxide fuelled SFRs

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

    Energy Technology Data Exchange (ETDEWEB)

    D' Agata, E., E-mail: elio.dagata@ec.europa.eu [European Commission, Joint Research Centre, Institute for Energy and Transport, P.O. Box 2, 1755 ZG Petten (Netherlands); Knol, S.; Fedorov, A.V. [Nuclear Research and Consultancy Group, P.O. Box 25, 1755 ZG Petten (Netherlands); Fernandez, A.; Somers, J. [European Commission, Joint Research Centre, Institute for Transuranium Elements, P.O. Box 2340, 76125 Karlsruhe (Germany); Klaassen, F. [Nuclear Research and Consultancy Group, P.O. Box 25, 1755 ZG Petten (Netherlands)

    2015-10-15

    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 {sup 241}Am 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 {sup 10}B 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.

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

    International Nuclear Information System (INIS)

    Falk, R.B.; Lagerquist, C.R.

    1975-01-01

    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 []parameters which yielded matches to the observed count histories. (auth)

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

    International Nuclear Information System (INIS)

    Rashydov, N.M.

    2002-01-01

    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 241 Am 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 241 Am and 137 Cs was at the level of 660 and 27 MBq/m 2 , respectively. Gamma spectroscopy and radiochemical methods were used to estimate the activity concentration of 137 Cs, 90 Sr, 238 Pu, 239+240 Pu, 241 Am. 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 137 Cs was (5.8±1,5)x10 6 , (7.4±1.1)x10 5 , and (2.6±0.2)x10 6 Bq/kg dry mass, respectively, and contamination by 241 Am was 47±5, 45±3 and 3.2±0.2 Bq/kg, respectively. The soil-to-plant transfer ratio for 137 Cs ranged lay within the interval of 0.2 to 0.03 Bq/kg : Bq/m 2 , the the transfer ratio for 241 Am did not exceed 7x10 -5 Bq/kg : Bq/m 2 . The coefficient of the relative contents of the 241 Am/ 239+240 Pu radionuclides in the various plant samples varied from 3.2 to 8.3, while for soil from

  3. 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

    2014-09-02

    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.

  4. Cleanex process: a versatile solvent extraction process for recovery and purification of lanthanides, americium, and curium

    International Nuclear Information System (INIS)

    Bigelow, J.E.; Collins, E.D.; King, L.J.

    1979-01-01

    At a concentration of 1 M in straight-chain hydrocarbon diluent, HDEHP will extract americium, curium, and other trivalent actinide and lanthanide elements from dilute acid or salt solutions. The solute is back-extracted with more concentrated acid, either nitric or hydrochloric. The process has been used in the continuous, countercurrent mode, but its greatest advantage arises in batch extractions where the excess acid can be titrated with NaOH to produce a final acidity of about 0.03 M. Under these conditions, 99% recovery can be achieved, usually in one stage. Cleanex was used on the 50-liter scale at the Transuranium Processing Plant at Oak Ridge for 12 years to provide a broad spectrum cleanup to transuranium elements before applying more sophisticated techniques for separating individual products. The process is also used routinely to recover excessive losses of curium and/or californium from plant waste streams. The solvent system is relatively resistant to radiation damage, being usable up to 200 W-h/liter

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

    International Nuclear Information System (INIS)

    Borba, Tania Regina de

    2010-01-01

    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)

  6. Experimental studies on the biokinetics of plutonium and americium in the cephalopod Octopus vulgaris

    International Nuclear Information System (INIS)

    Guary, J.C.; Fowler, S.W.

    1982-01-01

    Radiotracer experiments using the photon-emitters 237 Pu and 241 Am were performed to examine uptake, tissue distribution and retention of plutonium and americium in the cephalopod Octopus vulgaris Cuvier. A 2 wk exposure in contaminated sea water resulted in twice as much 237 Pu being taken up by whole octopus as 241 Am. Immediately following uptake approximately 41% and 73% of the 237 Pu and 241 Am respectively were located in the branchial hearts. Depuration rates for both radionuclides were identical; approximately 46% of both radionuclides initially incorporated were associated with a long-lived compartment which turned over very slowly (Tbsub(1/2) = 1.5 yr). Longer exposures to 241 Am resulted in an increase in the size of the slowly exchanging 241 Am pool in the octopus. After 2 mo depuration, the majority of the residual activity of both radionuclides was in the branchial hearts. On average 33% of the 241 Am ingested with food was assimilated into tissues, primarily the hepatopancreas. Different whole-body 241 Am excretion rates were observed at different times following assimilation and were related to transfer processes taking place within internal tissues, most notably between hepatopancreas and the branchial hearts. Relationships between circulatory and excretory functions of these 2 organs are discussed and a physiological mechanism is proposed to explain the observed patterns of 241 Am excretion in O. vulgaris. (orig.)

  7. Experimental studies on the biokinetics of plutonium and americium in the cephalopod Octopus vulgaris

    Energy Technology Data Exchange (ETDEWEB)

    Guary, J.C.; Fowler, S.W.

    1982-03-05

    Radiotracer experiments using the photon-emitters /sup 237/Pu and /sup 241/Am were performed to examine uptake, tissue distribution and retention of plutonium and americium in the cephalopod Octopus vulgaris Cuvier. A 2 wk exposure in contaminated sea water resulted in twice as much /sup 237/Pu being taken up by whole octopus as /sup 241/Am. Immediately following uptake approximately 41% and 73% of the /sup 237/Pu and /sup 241/Am respectively were located in the branchial hearts. Depuration rates for both radionuclides were identical; approximately 46% of both radionuclides initially incorporated were associated with a long-lived compartment which turned over very slowly (Tbsub(1/2) = 1.5 yr). Longer exposures to /sup 241/Am resulted in an increase in the size of the slowly exchanging /sup 241/Am pool in the octopus. After 2 mo depuration, the majority of the residual activity of both radionuclides was in the branchial hearts. On average 33% of the /sup 241/Am ingested with food was assimilated into tissues, primarily the hepatopancreas. Different whole-body /sup 241/Am excretion rates were observed at different times following assimilation and were related to transfer processes taking place within internal tissues, most notably between hepatopancreas and the branchial hearts. Relationships between circulatory and excretory functions of these 2 organs are discussed and a physiological mechanism is proposed to explain the observed patterns of /sup 241/Am excretion in O. vulgaris.

  8. Contrasts between the marine and freshwater biological interactions of plutonium and americium

    International Nuclear Information System (INIS)

    Livingston, H.D.; Bowen, V.T.

    1975-01-01

    Whether in lakes or the oceans the transuranic elements plutonium and americium are taken up by marine organisms, with concentration factors that would class them as nice, typical heavy metals. There is no evidence for strong, widespread discrimination against the transuranics by either plant or animal absorptive surfaces. In both freshwater and marine situations the major reservoir of Pu and Am soon becomes the sediments, and organisms are more exposed to uptake of these nuclides the closer is their ecological involvement with the sediments. Although there is little evidence that this can be an ionic strength effect, it does appear that Pu may be somewhat more available, biologically, in marine environments, and Am, conversely, in fresh water. We incline to the belief that details of these behaviors are usually controlled by local availability of organic complexers. No compelling evidence exists of increase in Pu concentration at higher levels of food chains; in marine situations this appears true of Am as well, but a few data suggest that in fresh water fish there is a progressive increase, in higher trophic levels, in the ratio Am to Pu. Although marine and fresh water biogeochemistries of transuranics are much more similar than we had expected, it will generally be dangerous to extrapolate from one to the other. In both systems there appears to us no question that we are observing real element biogeochemistry, not the redistribution of inert, labelled, fallout fragments

  9. Americium-241 use of measurement lead equivalent thickness for medical x-ray room: A review

    International Nuclear Information System (INIS)

    Mohd Khalid Matori; Husaini Saleh; Abd Aziz Mhd Ramli; Muhammad Jamal Md Isa; Mohd Firdaus Abd Rahman; Zainal Jamaluddin

    2010-01-01

    Lead equivalent thickness measurement of a shielding material in diagnostic radiology is very important to ensure that requirements for the purpose of radiation protection of patients, employees and the public are met. The Malaysian Ministry of Health (MOH) has established that the irradiation room must have sufficient shielding thickness, for example for general radiography it must be at least equal to 2.0 mm of Pb, for panoramic dental radiography at least equal to 1.5 mm of Pb and for mammography should be a minimum of 1.0 mm of Pb. This paper presents a technique using americium-241 source to test and verify the integrity of the shielding thickness in term of lead equivalent for X-ray room at health centres. Results of measurement of 30 irradiation rooms conducted from 2009 to mid 2010 were analyzed for this presentation. Technical comparison of the attenuation of gamma rays from Am-241 source through the walls of the irradiation room and pieces of lead were used to assess the lead equivalent thickness of the walls. Results showed that 96.7 % of the irradiation rooms tested meet the requirements of the Ministry of Health and is suitable for the installation of the intended diagnostic X-ray apparatus. Some specific positions such as door knobs and locks, electrical plug sockets were identified with potential to not met the required lead equivalent thickness hence may contribute to higher radiation exposure to workers and the public. (author)

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

    International Nuclear Information System (INIS)

    Bierkens, J.

    1986-01-01

    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 241 Am in the freshwater environment aim to establish a relation between the behavior of 241 Am 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 241 Am with humic acids and competition with trivalent cations such as A1 and Fe, were proven to be significant on the speciation of 241 Am. Based on the registration of the 241 Am uptake by a large number of freshwater organisms, the crayfish Astacus leptodactylus Eschscholtz was chosen to study the whole-body uptake of 241 Am, 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 241 Am in the hemolymph and the hepatopancreas, and its subcellular distribution in the digestive gland. Finally, by comparing the physiology of 241 Am with some other metals ( 240 Pu, 64 Cu, 198 Au) with analogous or contradictional properties, we tried to find out whether the behavior of 241 Am in organisms can be explained from its chemical characteristics

  11. Plutonium and americium recovery from spent molten-salt-extraction salts with aluminum-magnesium alloys

    International Nuclear Information System (INIS)

    Cusick, M.J.; Sherwood, W.G.; Fitzpatrick, R.F.

    1984-01-01

    Development work was performed to determine the feasibility of removing plutonium and americium from spent molten-salt-extraction (MSE) salts using Al-Mg alloys. If the product buttons from this process are compatible with subsequent aqueous processing, the complex chloride-to-nitrate aqueous conversion step which is presently required for these salts may be eliminated. The optimum alloy composition used to treat spent 8 wt % MSE salts in the past yielded poor phase-disengagement characteristics when applied to 30 mol % salts. After a limited investigation of other alloy compositions in the Al-Mg-Pu-Am system, it was determined that the Al-Pu-Am system could yield a compatible alloy. In this system, experiments were performed to investigate the effects of plutonium loading in the alloy, excess magnesium, age of the spent salt on actinide recovery, phase disengagement, and button homogeneity. Experimental results indicate that 95 percent plutonium recoveries can be attained for fresh salts. Further development is required for backlog salts generated prior to 1981. A homogeneous product alloy, as required for aqueous processing, could not be produced

  12. 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.

  13. Preparation of curium-americium oxide microspheres by resin-bead loading

    International Nuclear Information System (INIS)

    Chattin, F.R.; Benker, D.E.; Lloyd, M.H.; Orr, P.B.; Ross, R.G.; Wiggins, J.T.

    1980-01-01

    Resin-bead loading and calcination techniques have been used to produce all curium and americium oxide feed material (about 2.2 kg) for HFIR targets since 1971. The process based on Dowex 50W resin has progressed from a series of test runs, through special production runs, into routine production in permanent equipment beginning in 1975. Key attributes of this process are its reliability, high yields, and ease of operation. The process is suited for remote operation in hot cells. Yields approaching 95% are routinely obtained and only one unacceptable product has been generated during routine production operations. There have been no problems in fabricating targets from this oxide or in the subsequent irradiation of these targets. The present scale of production of 150 to 250 g/y supplies the present need and is comparable with the level of other chemical process operations at TRU. Since the annual production is accomplished in two 8 to 12 day periods, there has been no reason to consider further scale-up. However, the rate of production could easily be doubled by simply adding a second set of calcination equipment

  14. 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).

  15. Multicompartment kinetic models for the metabolism of americium, plutonium and uranium in rats

    International Nuclear Information System (INIS)

    Sontag, W.

    1986-01-01

    To examine the kinetic behaviour of americium, plutonium and uranium in male and female rats, an extended mammillary model has been developed, composed of 10 compartments connected with 17 linear transfer coefficients. The 10 compartments describe the behaviour of the three nuclides in the blood, skeleton, liver and kidney; the remaining activity is assigned to one residual organ. Each organ is divided into two compartments, short- and long-term. In the skeleton the short-term compartment has been assumed to be the bone surface and marrow, and the long-term compartment the deep bone; in the liver, evidence suggests that the short-term compartment is physiologically associated with lysosomes and the long-term compartment identical with telolysosomes. Influence of age, sex and different nuclides on the transfer coefficients and the absorbed radiation dose are discussed. By using the transfer coefficients calculated for intravenous injection, the behaviour of the nuclides in skeleton and liver during continuous intake has been calculated. The behaviour of the three nuclides in skeleton and liver after intravenous injection has also been calculated with the additional assumption that from the fifth day the animals were treated continuously with a chelating agent. (UK)

  16. Incorporation of plutonium, americium and curium into the Irish Sea seabed by biological activity

    Energy Technology Data Exchange (ETDEWEB)

    Kershaw, P J; Swift, D J; Pentreath, R J; Lovett, M B

    1984-12-01

    Bioturbation was considered as a potentially significant mechanism for the incorporation of long-lived radionuclides into the seabed and in particular the activities of a large echiuran Maximulleria lankesteri. Radionuclides of the transuranium elements plutonium, americium and cirium are discharged into the Irish Sea under authorization as part of the low-level liquid effluent from the British Nuclear Fuels plc reprocessing plant at Sellafield, Cumbria, England. The distribution of Pu-239, 240, Pu-238, Am-241, Cm-244 and Cm-242 concentrations and the Pu-239, 240/Pu-238 quotient in samples taken in April and May 1983 from the sediment surface, burrow linings, sediments adjacent to burrows, and the gut contents and body of a large M. lankesteri clearly indicate that bioturbation is responsible, at least in part, for the incorporation of these radionuclides to depths of up to 140 cm. This area of sediments represents a significant present-day sink, but the permanence of this sink and the likelihood that radioactivity will be remobilized and be returned to man, depends on a large number of factors. 15 references, 18 figures.

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

    International Nuclear Information System (INIS)

    Nielsen, R.D.

    1982-06-01

    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

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

    International Nuclear Information System (INIS)

    O'Donnell, F.R.; Etnier, E.L.; Holton, G.A.; Travis, C.C.

    1981-10-01

    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

  19. Anthropogenic 236U recorded in annually banded coral skeleton at Majuro atoll, the equatorial Pacific

    International Nuclear Information System (INIS)

    Sakaguchi, Aya; Eto, Asuka; Takahashi, Yoshio; Steier, Peter; Yamazaki, Atsuko; Watanabe, Tsuyoshi; Sasaki, Keiichi; Yamano, Hiroya

    2013-01-01

    Historical 236 U/ 238 U atom ratio and concentration of 236 U were determined by Accelerator Mass Spectrometry (AMS) in skeletons of dated modern coral core sample collected from Majuro atoll, equatorial Pacific, to reconstruct anthropogenic 236 U inputs to the Equatorial Pacific. The maximum hydrogen bomb-pulses of 236 U/ 238 U and 236 U concentration, 2.83x10 -9 and 1.85x10 7 atom/g, in an annually resolved coral core were captured in 1954 (Operation Castle at Bikini and Enewetok atolls). The values were abruptly decreased in a few years, and they have been gradually decreased over time. Our results allow studies of not only the present distribution pattern, but gives access to the temporal evolution of 236 U in surface seawater of North Equatorial Current which is introduced to the Japan Sea and the North West Pacific Ocean as Kuroshio and Tsushima currents over the past decades. (author)

  20. Anthropogenic 236U in Danish Seawater: Global Fallout versus Reprocessing Discharge

    DEFF Research Database (Denmark)

    Qiao, Jixin; Steier, Peter; Nielsen, Sven Poul

    2017-01-01

    This work focuses on the occurrence of 236U in seawater along Danish coasts, which is the sole water-exchange region between the North Sea-Atlantic Ocean and the Baltic Sea. Seawater collected in 2013 and 2014 were analyzed for 236U (as well as 238U and 137Cs). Our results indicate that 236U...... seawater. However, unexpectedly high 236U/238U ratios as well as high 236U concentrations were observed at low-salinity locations of the Baltic Sea. While this feature might be interpreted as a clue for another significant 236U input in the Baltic Sea, it may also be caused by the complexity of water...... currents or slow turnover rate....

  1. Anthropogenic 236U in Danish Seawater: Global Fallout versus Reprocessing Discharge.

    Science.gov (United States)

    Qiao, Jixin; Steier, Peter; Nielsen, Sven; Hou, Xiaolin; Roos, Per; Golser, Robin

    2017-06-20

    This work focuses on the occurrence of 236 U in seawater along Danish coasts, which is the sole water-exchange region between the North Sea-Atlantic Ocean and the Baltic Sea. Seawater collected in 2013 and 2014 were analyzed for 236 U (as well as 238 U and 137 Cs). Our results indicate that 236 U concentrations in Danish seawater are distributed within a relatively narrow range of (3.6-8.2) × 10 7 atom/L and, to a certain extent, independent of salinity. 236 U/ 238 U atomic ratios in Danish seawater are more than 4 times higher than the estimated global fallout value of 1× 10 -9 . The levels of 236 U/ 238 U atomic ratios obtained are comparable to those reported for the open North Sea and much higher than several other open oceans worldwide. This indicates that besides the global fallout input, the discharges from the two major European nuclear reprocessing plants are dominating sources of 236 U in Danish seawater. However, unexpectedly high 236 U/ 238 U ratios as well as high 236 U concentrations were observed at low-salinity locations of the Baltic Sea. While this feature might be interpreted as a clue for another significant 236 U input in the Baltic Sea, it may also be caused by the complexity of water currents or slow turnover rate.

  2. The extraction of lanthanides and americium by benzyldiakylamines and benzyltrialkylammonium nitrates from the nitrate solutions; structure and aggregation of their salts

    International Nuclear Information System (INIS)

    Jedinakova, V.; Zilkova, J.; Dvorak, Z.; Vojtiskova, M.

    1982-01-01

    Benzyldialkylamine and benzyltrialkylammonium nitrates were used for the extraction of lanthanides and americium from aqueous nitrate solutions. The dependence of the extraction performance for Ln(III) and Am(III) on the concentration of nitric acid, the kind and concentration of salting-out agents in the aqueous phase, and the kind of solvent were investigated. The extraction of Am(III) is compared with the extraction of lanthanides. The difference in distribution coefficients for lanthanides and americium can be utilized for the separation of lanthanides and americium. Using vapor phase osmometry and cryoscopy the association of these compounds was measured at 5.5deg, 25deg and 37deg C, allowing rough estimates of ΔH and ΔS for the formation of the aggregates, monomers in the case of benzyldiethylamine, benzyldibutylamine, benzyldihexylamine and benzyldioctylamine, tetramers for the benzyldibutylamine nitrate and tetramers for benzyldimethyldodecylammonium nitrate. (author)

  3. 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)

    Baston, G.M.N.; Berry, J.A.; Brownsword, M.; Heath, T.G.; Tweed, C.J.; Williams, S.J.

    1995-01-01

    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

  4. SPHERE: Irradiation of sphere-pac fuel of UPuO2−x containing 3% Americium

    International Nuclear Information System (INIS)

    D’Agata, E.; Hania, P.R.; McGinley, J.; Somers, J.; Sciolla, C.; Baas, P.J.; Kamer, S.; Okel, R.A.F.; Bobeldijk, I.; Delage, F.; Bejaoui, S.

    2014-01-01

    Highlights: • SPHERE is designed to check the behaviour of MADF sphere-pac concept. • MADF sphere-pac are compared with MADF pellet. • Swelling, helium release and restructuring behaviour will be the main output of the experiment. • An experiment to check sphere-pac MABB fuel behaviour is now under design. - Abstract: Americium is a strong contributor to the long term radiotoxicity of high activity nuclear waste. Transmutation by irradiation in nuclear reactors of long-lived nuclides like 241 Am is therefore an option for the reduction of radiotoxicity of waste packages to be stored in a repository. The SPHERE irradiation experiment is the latest of a series of European experiments on americium transmutation (e.g. EFTTRA-T4, EFTTRA-T4bis, HELIOS, MARIOS) performed in the HFR (High Flux Reactor). The SPHERE experiment is carried out in the framework of the 4-year project FAIRFUELS of the EURATOM 7th Framework Programme (FP7). During the past years of experimental works in the field of transmutation and tests of innovative nuclear fuels, the release or trapping of helium as well as helium induced fuel swelling have been shown to be the key issues for the design of Am-bearing targets. The main objective of the SPHERE experiment is to study the in-pile behaviour of fuel containing 3% of americium and to compare the behaviour of sphere-pac fuel to pellet fuel, in particular the role of microstructure and temperature on fission gas release (mainly He) and on fuel swelling. The SPHERE experiment is being irradiated since September 2013 in the HFR in Petten (The Netherlands) and is expected to be terminated in spring 2015. The experiment has been designed to last up to 18 reactor cycles (corresponding to 18 months) but may reach its target earlier. This paper discusses the rationale and objective of the SPHERE experiment and provides a general description of its design

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

    International Nuclear Information System (INIS)

    Pimpl, M.; Schuettelkopf, H.

    1979-12-01

    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.) [de

  6. Experiments comparing the uptake of americium from chloride media using extraction chromatography

    International Nuclear Information System (INIS)

    FitzPatrick, J.R.; Schake, B.S.; Schulte, L.D.; Martinez, B.T.; Salazar, R.R.

    1995-01-01

    Clean-up of actinide effluent waste steams is of increasing importance at the Los Alamos Plutonium Facility, TA-55, and removing the actinide elements to very low levels allows less radioactivity to go the Los Alamos National Laboratory Water Treatment Facility, TA-50, thus reducing the number of drums of TRU waste. Americium (Am) is a difficult element to remove from chloride media because the +3 state is difficult to oxidize and chelating resins work better with elements such as plutonium which are more readily oxidized to the +4 and/or +6 state. Currently in hydrochloric acid (HC1) media, the acidic liquid waste is neutralized with potassium hydroxide to precipitate the metal hydroxides, before disposal to TA-50. This process is not very efficient. The removal of Am from chloride media was compared using a series of resins, some commercial and some made in our laboratory, using different percentages by weight of octyl(phenyl)-N,N-diiso- butylcarbamoyl-methylphosphine oxide (CMPO ) along with diamyl amylphosphonate (DAAP) or tributyl phosphate (TBP) as diluents. Resins were also made with no added diluent. Early comparisons using small-scale contact studies with 0.5 grams of resin in 0.1M-12M HC1, and subsequent small-scale flow experiments show a trend in which Am uptake is proportional to the amount of CMPO on the resins and the diluent plays a minor role in the uptake of Am from these solutions. Redox chemistry effects were also investigated. From these studies, it is possible to determine the best conditions for the removal of Am from HC1 media thus reducing the gross alpha content of the waste stream by a factor of 10-100 which reduces the number of barrels of waste produced at the Water Treatment Facility

  7. Concentrations of plutonium and americium in plankton from the western Mediterranean Sea.

    Science.gov (United States)

    Sanchez-Cabeza, Joan-Albert; Merino, Juan; Masqué, Pere; Mitchell, Peter I; Vintró, L León; Schell, William R; Cross, Lluïsa; Calbet, Albert

    2003-07-20

    Understanding the transfer of radionuclides through the food chain leading to man and in particular, the uptake of transuranic nuclides by plankton, is basic to assess the potential radiological risk of the consumption of marine products by man. The main sources of transuranic elements in the Mediterranean Sea in the past were global fallout and the Palomares accident, although at present smaller amounts are released from nuclear establishments in the northwestern region. Plankton from the western Mediterranean Sea was collected and analyzed for plutonium and americium in order to study their biological uptake. The microplankton fractions accounted for approximately 50% of the total plutonium contents in particulate form. At Garrucha (Palomares area), microplankton showed much higher 239,240 Pu activity, indicating the contamination with plutonium from the bottom sediments. Concentration factors were within the range of the values recommended by the International Atomic Energy Agency. Continental shelf mesoplankton was observed to efficiently concentrate transuranics. In open seawaters, concentrations were much lower. We speculate that sediments might play a role in the transfer of transuranics to mesoplankton in coastal waters, although we cannot discard that the difference in species composition may also play a role. In Palomares, both 239,240 Pu and 241Am showed activities five times higher than the mean values observed in continental shelf mesoplankton. As the plutonium isotopic ratios in the contaminated sample were similar to those found in material related to the accident, the contamination was attributed to bomb debris from the Palomares accident. Concentration factors in mesoplankton were also in relatively good agreement with the ranges recommended by IAEA. In the Palomares station the highest concentration factor was observed in the sample that showed predominance of the dynoflagellate Ceratium spp. Mean values of the enrichment factors showed, on

  8. Concentration and vertical distribution of plutonium and americium in Italian mosses and lichens

    International Nuclear Information System (INIS)

    Jia, G.; Desideri, D.; Guerra, F.; Meli, M.A.; Testa, C.

    1997-01-01

    The plutonium and americium concentration and vertical distribution in some Italian mosses and lichens have been determined. The 239,240 Pu, 238 Pu and 241 Am concentration ranges in tree trunk lichens 0.83-1.87, 0.052-0.154 and 0.180-0.770 Bq/kg, respectively. The corresponding values in tree mosses are higher and more scattered ranging from 0.321 to 4.96, from 0.029 to 0.171 and from 0.200 to 1.93 Bq/kg. The mean 238 Pu/ 239,240 Pu and 241 Am/ 239,240 Pu ratios are 0.088±0.037 and 0.38 ± 0.13 in lichens and 0.091±0.072 and 0.54±0.16 in tree mosses. The Pu and Am concentrations are relatively low in terrestrial mosses. The 239,240 Pu, 238 Pu and 241 Am vertical distributions in a terrestrial moss core (Neckera Crispa) collected near Urbino (central Italy) show an exponential decrease with the height. On the contrary the 241 Am vertical distribution in another terrestrial moss core (Sphagnum Compactum) collected in the Alps (northern Italy) shows an interesting peak at 16 cm which corresponds to the deposition of fallout from the nuclear weapon tests in 1960's. The 241 Am movement upward and downward in the moss core is also studied. The results show once again that both mosses and lichens are very effective accumulators of Pu and Am and that they can be used as good biological indicators of the radionuclide airborne pollution from nuclear facilities and nuclear weapon tests. They can play a very important role in cycling naturally or artificially enhanced radionuclides in the atmosphere over long time scales. (author)

  9. A review on the mass spectrometric studies of americium: Present status and future perspective.

    Science.gov (United States)

    Aggarwal, Suresh Kumar

    2018-01-01

    The manuscript reviews the various mass spectrometric techniques for analysis and chemical studies of Americium. These methods include thermal ionization mass spectrometry (TIMS), and inductively coupled plasma source mass spectrometry (ICPMS) for the determination of Am isotope ratios and concentration in nuclear fuel samples of interest in nuclear technology, and in complex biological and environmental samples. Ultra-sensitive mass spectrometric techniques of resonance-ionization mass spectrometry (RIMS), and accelerator-based mass spectrometry (AMS) are also discussed. The novel applications of electrospray ionization mass spectrometry (ESIMS) to understand the solution chemistry of Am and other actinides are presented. These studies are important in view of the world-wide efforts to develop novel complexing agents to separate lanthanides and minor actinides (Am, Np, and Cm) for partitioning and transmutation of minor actinides from the point of view of nuclear waste management. These mass spectrometry experiments are also of great interest to examine the covalent character of actinides with increasing atomic number. Studies on gas-phase chemistry of Am and its oxides with Knudsen effusion mass spectrometry (KEMS), Fourier-transform ion cyclotron resonance mass spectrometry (FTICR-MS), and laser-based experiments with reflectron time-of-flight mass spectrometer (R-ToF) are highlighted. These studies are important to understand the fundamental chemistry of 5f electrons in actinides. Requirement of certified isotopic reference materials of Am to improve the accuracy of experimental nuclear data (e.g., the half-life of 243 Am) is emphasized. © 2016 Wiley Periodicals, Inc. Mass Spec Rev. © 2016 Wiley Periodicals, Inc.

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

    International Nuclear Information System (INIS)

    McKay, W.A.; Strange, L.; Walker, M.I.; Halliwell, C.M.

    1992-01-01

    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 241 Am generally appeared to be about 20%. A review of earlier published concentrations of 239+240 Pu and 241 Am 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)

  11. Behavior of americium, curium, and certain fission products in fluoride melts in the presence of s olid extraction agents

    International Nuclear Information System (INIS)

    Alekseev, V.A.; Klokman, V.R.; Morozova, Z.E.; Ziv, V.S.

    1986-01-01

    The authors consider the behavior of americium, curium, and certain fission products (europium, cerium, yttrium, and strontium) in fluoride and chlode-fluoride melts in the presence of nonisomorphous solid phases: calcium fluoride and lanthanum and zirconium oxides. It is shown that the trace components enter the solid calcium fluoride in a regular fashion only in the presence of an adequate amount of oxygen in the melt. The effect of oxygen on the coprecipitation with calcium fluoride occurs because oxygen compounds of the elements must be formed in the melt, and these are then coprecipitated with the calcium fluoride

  12. 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......-I to Am-II transition. Good agreement was found between calculated and experimental equations of states for all phases, but the first three phases need larger U (α) parameters (where α represents the fraction of Hartree-Fock exchange energy replacing the DFT exchange energy) than the fourth phase in order...

  13. Determination of americium and curium using ion-exchange in the nitric-acid-methanol medium for environmental analysis

    International Nuclear Information System (INIS)

    Holm, E.; Fukai, R.

    1976-01-01

    While transplutonic elements are only slightly sorbed to anion exchangers from hydrochloric or nitric acid media, the presence of alcohol enhances the anionic exchange of these elements, especially in nitric and sulfuric solutions. In the present work a method has been developed for determining americium and curium in environmental samples, on the basis of the difference between the sorption characteristics to anion exchangers in the acid-methanol system of these transplutonic elements and those of plutonium, polonium and thorium. The method also permits us to perform sequential determination of plutonium, when necessary

  14. Co-precipitation of plutonium(IV) and americium(III) from nitric acid-oxalic acid solutions with bismuth oxalate

    International Nuclear Information System (INIS)

    Pius, I.C.; Noronha, D.M.; Chaudhury, Satyajeet

    2017-01-01

    Co-precipitation of plutonium and americium from nitric acid-oxalic acid solutions with bismuth oxalate has been investigated for the removal of these long lived α-active nuclides from waste solutions. Effect of concentration of bismuth and oxalic acid on the co-precipitation of Pu(IV) from 3 M HNO_3 has been investigated. Similar experiments were also carried out from 3.75 M HNO_3 on co-precipitation of Am(III) to optimize the conditions of precipitation. Strong co-precipitation of Pu(IV) and Am(III) with bismuth oxalate indicate feasibility of treatment of plutonium and americium bearing waste solutions. (author)

  15. 236 children with developmental hydrocephalus: causes and clinical consequences

    Science.gov (United States)

    Tully, Hannah M; Ishak, Gisele E; Rue, Tessa C; Dempsey, Jennifer C; Browd, Samuel R; Millen, Kathleen J; Doherty, Dan; Dobyns, William B

    2016-01-01

    Few systematic assessments of developmental forms of hydrocephalus exist. We reviewed MRIs and clinical records of patients with infancy-onset hydrocephalus. Among 411 infants, 236 had hydrocephalus with no recognizable extrinsic cause. These children were assigned to one of five subtypes and compared on the basis of clinical characteristics, developmental and surgical outcomes. At an average age of 5.3 years, 72% of children were walking independently and 87% could eat by mouth. 18% had epilepsy. Distinct patterns of associated malformations and syndromes were observed within each subtype. On average, children with aqueductal obstruction, cysts and encephaloceles had worse clinical outcomes than those with other forms of developmental hydrocephalus. 53% of surgically-treated patients experienced at least one shunt failure, but hydrocephalus associated with posterior fossa crowding required fewer shunt revisions. We conclude that each subtype of developmental hydrocephalus is associated with distinct clinical characteristics, syndromology, and outcomes, suggesting differences in underlying mechanisms. PMID:26184484

  16. Status of {sup 236}U analyses at ETH Zurich and the distribution of {sup 236}U and {sup 129}I in the North Sea in 2009

    Energy Technology Data Exchange (ETDEWEB)

    Christl, Marcus, E-mail: mchristl@ethz.ch [Laboratory of Ion Beam Physics, ETH Zurich, 8093 Zurich (Switzerland); Casacuberta, Nuria; Lachner, Johannes; Maxeiner, Sascha; Vockenhuber, Christof; Synal, Hans-Arno [Laboratory of Ion Beam Physics, ETH Zurich, 8093 Zurich (Switzerland); Goroncy, Ingo; Herrmann, Jürgen [Bundesamt für Seeschifffahrt und Hydrographie, Hamburg (Germany); Daraoui, Abdelouahed; Walther, Clemens; Michel, Rolf [Institut für Radioökologie und Strahlenschutz, Leibniz Universität Hannover (Germany)

    2015-10-15

    Compact, low energy accelerator mass spectrometry (AMS) has evolved over the past years as one of the most sensitive, selective, and robust techniques for the analysis of heavy and long lived radionuclides. In this study, we will first focus on the analytical capabilities of the compact AMS system TANDY, mainly for {sup 236}U analyses, and then present a new dual tracer approach, that combines {sup 129}I and {sup 236}U. The measured {sup 129}I/{sup 236}U ratios of samples collected in the North Sea in 2009 are in reasonable agreement with the expectations from documented or estimated releases from the two major nuclear reprocessing plants located at Sellafield (GB) and La Hague (F), suggesting that the {sup 129}I/{sup 236}U ratio can be used as a water mass tag in the North Atlantic region. However, our results indicate that, in contrast to {sup 129}I, additional contributions of bomb produced {sup 236}U cannot be neglected in the North Sea region. This complicates the simple and straight forward use of the {sup 129}I/{sup 236}U ratio as a quantitative tool for the calculation of transport times of North Sea water in the Arctic Ocean.

  17. 49 CFR 236.74 - Protection of insulated wire; splice in underground wire.

    Science.gov (United States)

    2010-10-01

    ... underground wire. 236.74 Section 236.74 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RULES, STANDARDS, AND INSTRUCTIONS GOVERNING... wire; splice in underground wire. Insulated wire shall be protected from mechanical injury. The...

  18. 42 CFR 435.236 - Individuals in institutions who are eligible under a special income level.

    Science.gov (United States)

    2010-10-01

    ... a special income level. 435.236 Section 435.236 Public Health CENTERS FOR MEDICARE & MEDICAID... in institutions who are eligible under a special income level. (a) If the agency provides Medicaid... not institutionalized; but (2) Have income below a level specified in the plan under § 435.722. (See...

  19. 49 CFR 236.16 - Electric lock, main track releasing circuit.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Electric lock, main track releasing circuit. 236... Rules and Instructions: All Systems General § 236.16 Electric lock, main track releasing circuit. When an electric lock releasing circuit is provided on the main track to permit a train or an engine to...

  20. 48 CFR 952.236 - Construction and architect-engineer contracts.

    Science.gov (United States)

    2010-10-01

    ... 48 Federal Acquisition Regulations System 5 2010-10-01 2010-10-01 false Construction and architect-engineer contracts. 952.236 Section 952.236 Federal Acquisition Regulations System DEPARTMENT OF ENERGY... Construction and architect-engineer contracts. ...

  1. 48 CFR 853.236-70 - VA Form 10-6298, Architect-Engineer Fee Proposal.

    Science.gov (United States)

    2010-10-01

    ... 48 Federal Acquisition Regulations System 5 2010-10-01 2010-10-01 false VA Form 10-6298, Architect-Engineer Fee Proposal. 853.236-70 Section 853.236-70 Federal Acquisition Regulations System DEPARTMENT OF...-Engineer Fee Proposal. VA Form 10-6298, Architect-Engineer Fee Proposal, shall be used as prescribed in 836...

  2. MODELING AND DESIGN STUDY USING HFC-236EA AS AN ALTERNATIVE REFRIGERANT IN A CENTRIFUGAL COMPRESSOR

    Science.gov (United States)

    The report gives results of an investigation of the operation of a centrifugal compressor--part of a chlorofluorocarbon (CFC)-114 chiller installation--with the new refrigerant hydrofluorocarbon (HFC)-236ea, a proposed alternative to CFC-114. A large set of CFC-236ea operating da...

  3. 48 CFR 852.236-82 - Payments under fixed-price construction contracts (without NAS).

    Science.gov (United States)

    2010-10-01

    ... manner; or (iv) Failure to comply in good faith with approved subcontracting plans, certifications, or... under other provisions of the contract or in accordance with the general law and regulations regarding... construction contracts (without NAS). 852.236-82 Section 852.236-82 Federal Acquisition Regulations System...

  4. 24 CFR 236.252 - First, second, and third mortgage insurance premiums.

    Science.gov (United States)

    2010-04-01

    ... insurance premiums. 236.252 Section 236.252 Housing and Urban Development Regulations Relating to Housing... insurance premiums. All of the provisions of § 207.252 of this chapter governing the first, second, and third mortgage insurance premiums shall apply to mortgages insured under this subpart, except: (a) Where...

  5. Excess of "2"3"6U in the northwest Mediterranean Sea

    International Nuclear Information System (INIS)

    Chamizo, E.; López-Lora, M.; Bressac, M.; Levy, I.; Pham, M.K.

    2016-01-01

    In this work, we present first "2"3"6U results in the northwestern Mediterranean. "2"3"6U is studied in a seawater column sampled at DYFAMED (Dynamics of Atmospheric Fluxes in the Mediterranean Sea) station (Ligurian Sea, 43°25′N, 07°52′E). The obtained "2"3"6U/"2"3"8U atom ratios in the dissolved phase, ranging from about 2 × 10"−"9 at 100 m depth to about 1.5 × 10"−"9 at 2350 m depth, indicate that anthropogenic "2"3"6U dominates the whole seawater column. The corresponding deep-water column inventory (12.6 ng/m"2 or 32.1 × 10"1"2 atoms/m"2) exceeds by a factor of 2.5 the expected one for global fallout at similar latitudes (5 ng/m"2 or 13 × 10"1"2 atoms/m"2), evidencing the influence of local or regional "2"3"6U sources in the western Mediterranean basin. On the other hand, the input of "2"3"6U associated to Saharan dust outbreaks is evaluated. An additional "2"3"6U annual deposition of about 0.2 pg/m"2 based on the study of atmospheric particles collected in Monaco during different Saharan dust intrusions is estimated. The obtained results in the corresponding suspended solids collected at DYFAMED station indicate that about 64% of that "2"3"6U stays in solution in seawater. Overall, this source accounts for about 0.1% of the "2"3"6U inventory excess observed at DYFAMED station. The influence of the so-called Chernobyl fallout and the radioactive effluents produced by the different nuclear installations allocated to the Mediterranean basin, might explain the inventory gap, however, further studies are necessary to come to a conclusion about its origin. - Highlights: • First "2"3"6U results in the northwest Mediterranean Sea are reported. • Anthropogenic "2"3"6U dominates the whole seawater column at DYFAMED station. • "2"3"6U deep-water column inventory exceeds by a factor of 2.5 the global fallout one. • Saharan dust intrusions are responsible for an annual "2"3"6U flux of 0.02 pg/m"2. • Further studies are necessary to explain the

  6. Uranium-236 in light water reactor spent fuel recycled to an enriching plant

    International Nuclear Information System (INIS)

    de la Garza, A.

    1977-01-01

    The introduction of 236 U to an enriching plant by recycling spent fuel uranium results in enriched products containing 236 U, a parasitic neutron absorber in reactor fuel. Convenient approximate methodology determines 235 236 U, and total uranium flowsheets with associated separative work requirements in enriching plant operations for use by investigators of the light water reactor fuel cycle not having recourse to specialized multicomponent cascade technology. Application of the methodology has been made to compensation of an enriching plant product for 236 U content and to the value at an enriching plant of spent fuel uranium. The approximate methodology was also confirmed with more exact calculations and with some experience with 236 U in an enriching plant

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

    International Nuclear Information System (INIS)

    Taylor, D.M.

    1988-01-01

    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

  8. Temperature and concentration dependences of the electrical resistivity for alloys of plutonium with americium under normal conditions

    Science.gov (United States)

    Tsiovkin, Yu. Yu.; Povzner, A. A.; Tsiovkina, L. Yu.; Dremov, V. V.; Kabirova, L. R.; Dyachenko, A. A.; Bystrushkin, V. B.; Ryabukhina, M. V.; Lukoyanov, A. V.; Shorikov, A. O.

    2010-01-01

    The temperature and concentration dependences of the electrical resistivity for alloys of americium with plutonium are analyzed in terms of the multiband conductivity model for binary disordered substitution-type alloys. For the case of high temperatures ( T > ΘD, ΘD is the Debye temperature), a system of self-consistent equations of the coherent potential approximation has been derived for the scattering of conduction electrons by impurities and phonons without any constraints on the interaction intensity. The definitions of the shift and broadening operator for a single-electron level are used to show qualitatively and quantitatively that the pattern of the temperature dependence of the electrical resistivity for alloys is determined by the balance between the coherent and incoherent contributions to the electron-phonon scattering and that the interference conduction electron scattering mechanism can be the main cause of the negative temperature coefficient of resistivity observed in some alloys involving actinides. It is shown that the great values of the observed resistivity may be attributable to interband transitions of charge carriers and renormalization of their effective mass through strong s-d band hybridization. The concentration and temperature dependences of the resistivity for alloys of plutonium and americium calculated in terms of the derived conductivity model are compared with the available experimental data.

  9. 49 CFR 236.401 - Automatic block signal system and interlocking standards applicable to traffic control systems.

    Science.gov (United States)

    2010-10-01

    ... TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Traffic Control Systems Standards § 236.401 Automatic... 49 Transportation 4 2010-10-01 2010-10-01 false Automatic block signal system and interlocking standards applicable to traffic control systems. 236.401 Section 236.401 Transportation Other Regulations...

  10. Plutonium, americium, and uranium in blow-sand mounds of safety-shot sites at the Nevada Test Site and the Tonopah Test Range

    International Nuclear Information System (INIS)

    Essington, E.H.; Gilbert, R.O.; Wireman, D.L.; Brady, D.N.; Fowler, E.B.

    1977-01-01

    Blow-sand mounds or miniature sand dunes and mounds created by burrowing activities of animals were investigated by the Nevada Applied Ecology Group (NAEG) to determine the influence of mounds on plutonium, americium, and uranium distributions and inventories in areas of the Nevada Test Site and Tonopah Test Range. Those radioactive elements were added to the environment as a result of safety experiments of nuclear devices. Two studies were conducted. The first was to estimate the vertical distribution of americium in the blow-sand mounds and in the desert pavement surrounding the mounds. The second was to estimate the amount or concentration of the radioactive materials accumulated in the mound relative to the desert pavement. Five mound types were identified in which plutonium, americium, and uranium concentrations were measured: grass, shrub, complex, animal, and diffuse. The mount top (that portion above the surrounding land surface datum), the mound bottom (that portion below the mound to a depth of 5 cm below the surrounding land surface datum), and soil from the immediate area surrounding the mound were compared separately to determine if the radioactive elements had concentrated in the mounds. Results of the studies indicate that the mounds exhibit higher concentrations of plutonium, americium, and uranium than the immediate surrounding soil. The type of mound does not appear to have influenced the amount of the radioactive material found in the mound except for the animal mounds where the burrowing activities appear to have obliterated distribution patterns

  11. In situ characterization of uranium and americium oxide solid solution formation for CRMP process: first combination of in situ XRD and XANES measurements.

    Science.gov (United States)

    Caisso, Marie; Picart, Sébastien; Belin, Renaud C; Lebreton, Florent; Martin, Philippe M; Dardenne, Kathy; Rothe, Jörg; Neuville, Daniel R; Delahaye, Thibaud; Ayral, André

    2015-04-14

    Transmutation of americium in heterogeneous mode through the use of U1-xAmxO2±δ ceramic pellets, also known as Americium Bearing Blankets (AmBB), has become a major research axis. Nevertheless, in order to consider future large-scale deployment, the processes involved in AmBB fabrication have to minimize fine particle dissemination, due to the presence of americium, which considerably increases the risk of contamination. New synthesis routes avoiding the use of pulverulent precursors are thus currently under development, such as the Calcined Resin Microsphere Pelletization (CRMP) process. It is based on the use of weak-acid resin (WAR) microspheres as precursors, loaded with actinide cations. After two specific calcinations under controlled atmospheres, resin microspheres are converted into oxide microspheres composed of a monophasic U1-xAmxO2±δ phase. Understanding the different mechanisms during thermal conversion, that lead to the release of organic matter and the formation of a solid solution, appear essential. By combining in situ techniques such as XRD and XAS, it has become possible to identify the key temperatures for oxide formation, and the corresponding oxidation states taken by uranium and americium during mineralization. This paper thus presents the first results on the mineralization of (U,Am) loaded resin microspheres into a solid solution, through in situ XAS analysis correlated with HT-XRD.

  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. Novel Americium Treatment Process for Surface Water and Dust Suppression Water

    International Nuclear Information System (INIS)

    Tiepel, E.W.; Pigeon, P.; Nesta, S.; Anderson, J.

    2006-01-01

    The Rocky Flats Environmental Technology Site (RFETS), a former nuclear weapons production plant, has been remediated under CERCLA and decommissioned to become a National Wildlife Refuge. The site conducted this cleanup effort under the Rocky Flats Cleanup Agreement (RFCA) that established limits for the discharge of surface and process waters from the site. At the end of 2004, while a number of process buildings were undergoing decommissioning, routine monitoring of a discharge pond (Pond A-4) containing approximately 28 million gallons of water was discovered to have been contaminated with a trace amount of Americium-241 (Am-241). While the amount of Am-241 in the pond waters was very low (0.5 - 0.7 pCi/l), it was above the established Colorado stream standard of 0.15 pCi/l for release to off site drainage waters. The rapid successful treatment of these waters to the regulatory limit was important to the site for two reasons. The first was that the pond was approaching its hold-up limit. Without rapid treatment and release of the Pond A-4 water, typical spring run-off would require water management actions to other drainages onsite or a mass shuttling of water for disposal. The second reason was that this type of contaminated water had not been treated to the stringent stream standard at Rocky Flats before. Technical challenges in treatment could translate to impacts on water and secondary waste management, and ultimately, cost impacts. All of the technical challenges and specific site criteria led to the conclusion that a different approach to the treatment of this problem was necessary and a crash treatability program to identify applicable treatment techniques was undertaken. The goal of this program was to develop treatment options that could be implemented very quickly and would result in the generation of no high volume secondary waste that would be costly to dispose. A novel chemical treatment system was developed and implemented at the RFETS to treat Am

  14. European roe deer antlers as an environmental archive for fallout 236U and 239Pu

    International Nuclear Information System (INIS)

    Froehlich, M.B.; Steier, P.; Wallner, G.; Fifield, L.K.

    2016-01-01

    Anthropogenic 236 U and 239 Pu were measured in European roe deer antlers hunted between 1955 and 1977 which covers and extends beyond the period of intensive nuclear weapons testing (1954–1962). The antlers were hunting trophies, and hence the hunting area, the year of shooting and the approximate age of each animal is given. Uranium and plutonium are known to deposit in skeletal tissue. Since antler histology is similar to bone, both elements were expected in antlers. Furthermore, roe deer shed their antlers annually, and hence antlers may provide a time-resolved environmental archive for fallout radionuclides. The radiochemical procedure is based on a Pu separation step by anion exchange (Dowex 1 × 8) and a subsequent U purification by extraction chromatography using UTEVA ® . The samples were measured by Accelerator Mass Spectrometry at the VERA facility (University of Vienna). In addition to the 236 U and 239 Pu concentrations, the 240 Pu/ 239 Pu isotopic ratios were determined with a mean value of 0.172 ± 0.023 which is in agreement with the ratio of global fallout (∼0.18). Rather high 236 U/ 238 U ratios of the order of 10 −6 were observed. These measured ratios, where the 236 U arises only from global fallout, have implications for the use of the 236 U/ 238 U ratio as a fingerprint for nuclear accidents or releases from nuclear facilities. Our investigations have shown the potential to use antlers as a temporally resolved archive for the uptake of actinides from the environment. - Highlights: • Roe deer antlers were studied as an environmental archive for the retrospective study of fallout isotopes 236 U and 239 Pu. • The rather high 236 U/ 238 U ratios of about 10 −6 suggest 236 U as a fingerprint tool for nuclear material releases. • The 240 Pu/ 239 Pu atom ratio underpins global fallout as the main anthropogenic contributor in antlers.

  15. Plutonium, americium, 90Sr and 137Cs in bones of red fox (Vulpes vulpes) from Eastern Poland

    International Nuclear Information System (INIS)

    Mietelski, J.W.; Tomankiewicz, E.; Gaca, P.; Blazej, S.; Kitowski, I.

    2008-01-01

    90 Sr, 238,239+240 Pu, 241 Am and 137 Cs activity concentrations are presented in the jaw bones of red fox (Vulpes vulpes) from eastern Poland. The short description of the applied radiochemical method is presented. Activity concentrations for 90 Sr ranged between 2.2±0.7 and 41.4±4.7 Bq/kg (aw = ash weight). Average results for plutonium and americium are on the level of 10 mBq/kg (aw). No clear relationship was observed among the radionuclide concentrations. The samples analyzed do not show elevated contamination levels when compared with results of bones of small animals (rodent or insectivorous mammals) determined previously, so no accumulation of bone seeking isotopes on higher step of food-chain is concluded. (author)

  16. Ecological distribution and fate of plutonium and americium in a processing waste pond on the Hanford Reservation

    International Nuclear Information System (INIS)

    Emergy, R.M.; Klopfer, D.C.; McShane, M.C.

    1978-01-01

    U Pond, located on the Hanford Reservation, has received low-level quantities of plutonium (Pu) and americium (Am) longer than any other aquatic environment in the world. Its ecological complexity and content of transuranics make it an ideal resource for information concerning the movement of these actinides within and out of an aquatic ecosystem. U Pond has been intensively inventoried for Pu concentrations in the ecological compartments and characterized limnologically in terms of its physicochemial parameters, biological productivity, and community structure. This work provides a basis for evaluating the pond's performance in retaining waste transuranics. The quantitative estimation of export routes developed by this study is important in determining how effectively such ponds act as retainers for transuranic wastes

  17. Comparative study of G2 delay and survival after /sup 241/Americium-. cap alpha. and /sup 60/Cobalt-. gamma. irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Luecke-Huhle, C.; Comper, W.; Hieber, L.; Pech, M.

    1982-06-01

    Survival and G2 delay following exposure to either /sup 60/Cobalt-..gamma..-rays or /sup 241/Americium-..cap alpha..-particles were studied in eight mammalian cell lines of human and animal origin including human fibroblasts from normal individuals and from patients with Ataxia telangiectasia or Fanconi's anemia. For both endpoints the effectiveness of alpha particle was greater as compared to ..gamma..-rays. RBE values for G2 delay (4.6-9.2) were in general comparable to RBE values derived from initial slopes of survival curves but higher compared to the ratio of mean inactivation doses. Ataxia cells were particularly sensitive to cell killing by ..gamma..-irradiation, however, showed average sensitivity to ..cap alpha..-particles of high LET. With the exception of Ataxia cells, cell killing and G2 delay seem to be related processes if individual cell cycle parameters are taken into account.

  18. Crystallographic and Spectroscopic Characterization of Americium Complexes Containing the Bis[(phosphino)methyl]pyridine-1-oxide (NOPOPO) Ligand Platform

    Energy Technology Data Exchange (ETDEWEB)

    Corbey, Jordan F. [Pacific Northwest National Laboratory, Richland, Washington 99354, United States; Rapko, Brian M. [Pacific Northwest National Laboratory, Richland, Washington 99354, United States; Wang, Zheming [Pacific Northwest National Laboratory, Richland, Washington 99354, United States; McNamara, Bruce K. [Pacific Northwest National Laboratory, Richland, Washington 99354, United States; Surbella, Robert G. [Pacific Northwest National Laboratory, Richland, Washington 99354, United States; Pellegrini, Kristi L. [Pacific Northwest National Laboratory, Richland, Washington 99354, United States; Schwantes, Jon M. [Pacific Northwest National Laboratory, Richland, Washington 99354, United States

    2018-02-06

    Abstract The crystal structures of americium species containing a common multi-functional phosphine oxide ligand, reported for its ability to extract f elements from acidic solutions, namely 2,6-[Ph2P(O)CH2]2C5H3-NO, L, have finally been determined after over three decades of separations studies involving these species and their surrogates. The molecular compounds Am(L)(NO3)3, Am 1:1, and [Am(L)2(NO3)][NO3]2, Am 2:1, along with their neodymium and europium analogs were synthesized and characterized using single-crystal X-ray crystallography, attenuated total reflectance Fourier transform infrared (ATR) spectroscopy and luminescence spectroscopy to provide a comprehensive comparison with new and known analogous complexes.

  19. Separation of americium by liquid-liquid extraction using diglycol-amides water-soluble complexing agents

    Energy Technology Data Exchange (ETDEWEB)

    Chapron, S.; Marie, C.; Pacary, V.; Duchesne, M.T.; Miguirditchian, M. [CEA, Centre de Marcoule, Nuclear Energy Division, RadioChemistry and Processses Departement, 30207 Bagnols-sur-Ceze (France); Arrachart, G.; Pellet-Rostaing, S. [Institut de Chimie Separative de Marcoule, LTSM, Bat 426, F-30207 Bagnols-sur- Ceze (France)

    2016-07-01

    Recycling americium (Am) alone from spent nuclear fuels is an important option studied for the future nuclear cycle (Generation IV systems) since Am belongs to the main contributors of the long-term radiotoxicity and heat power of final waste. Since 2008, a liquid-liquid extraction process called EXAm has been developed by the CEA to allow the recovery of Am alone from a PUREX raffinate (a dissolution solution already cleared from U, Np and Pu). A mixture of DMDOHEMA (N,N'-dimethyl-N,N'-dioctyl-2-(2-(hexyloxy)ethyl)-malonamide) and HDEHP (di-2-ethylhexylphosphoric acid) in TPH is used as the solvent and the Am/Cm selectivity is improved using TEDGA (N,N,N',N'-tetraethyl-diglycolamide) as a selective complexing agent to maintain Cm and heavier lanthanides in the acidic aqueous phase (5 M HNO{sub 3}). Americium is then stripped selectively from light lanthanides at low acidity (pH=3) with a poly-aminocarboxylic acid. The feasibility of sole Am recovery was already demonstrated during hot tests in ATALANTE facility and the EXAm process was adapted to a concentrated raffinate to optimize the process compactness. The speciation of TEDGA complexes formed in the aqueous phase with Am, Cm and lanthanides was studied to better understand and model the behavior of TEDGA in the process. Some Ln-TEDGA species are extracted into the organic phase and this specific chemistry might play a role in the Am/Cm selectivity improvement. Hence the hydrophilicity-lipophilicity balance of the complexing agent is an important parameter. In this comprehensive study, new analogues of TEDGA were synthesized and tested in the EXAm process conditions to understand the relationship between their structure and selectivity. New derivatives of TEDGA with different N-alkyl chain lengths and ramifications were synthesized. The impact of lipophilicity on ligand partitioning and Am/Cm selectivity was investigated. (authors)

  20. First measurements of (236)U concentrations and (236)U/(239)Pu isotopic ratios in a Southern Hemisphere soil far from nuclear test or reactor sites.

    Science.gov (United States)

    Srncik, M; Tims, S G; De Cesare, M; Fifield, L K

    2014-06-01

    The variation of the (236)U and (239)Pu concentrations as a function of depth has been studied in a soil profile at a site in the Southern Hemisphere well removed from nuclear weapon test sites. Total inventories of (236)U and (239)Pu as well as the (236)U/(239)Pu isotopic ratio were derived. For this investigation a soil core from an undisturbed forest area in the Herbert River catchment (17°30' - 19°S) which is located in north-eastern Queensland (Australia) was chosen. The chemical separation of U and Pu was carried out with a double column which has the advantage of the extraction of both elements from a relatively large soil sample (∼20 g) within a day. The samples were measured by Accelerator Mass Spectrometry using the 14UD pelletron accelerator at the Australian National University. The highest atom concentrations of both (236)U and (239)Pu were found at a depth of 2-3 cm. The (236)U/(239)Pu isotopic ratio in fallout at this site, as deduced from the ratio of the (236)U and (239)Pu inventories, is 0.085 ± 0.003 which is clearly lower than the Northern Hemisphere value of ∼0.2. The (236)U inventory of (8.4 ± 0.3) × 10(11) at/m(2) was more than an order of magnitude lower than values reported for the Northern Hemisphere. The (239)Pu activity concentrations are in excellent agreement with a previous study and the (239+240)Pu inventory was (13.85 ± 0.29) Bq/m(2). The weighted mean (240)Pu/(239)Pu isotopic ratio of 0.142 ± 0.005 is slightly lower than the value for global fallout, but our results are consistent with the average ratio of 0.173 ± 0.027 for the southern equatorial region (0-30°S). Copyright © 2014 Elsevier Ltd. All rights reserved.

  1. Chronology of Pu isotopes and 236U in an Arctic ice core.

    Science.gov (United States)

    Wendel, C C; Oughton, D H; Lind, O C; Skipperud, L; Fifield, L K; Isaksson, E; Tims, S G; Salbu, B

    2013-09-01

    In the present work, state of the art isotopic fingerprinting techniques are applied to an Arctic ice core in order to quantify deposition of U and Pu, and to identify possible tropospheric transport of debris from former Soviet Union test sites Semipalatinsk (Central Asia) and Novaya Zemlya (Arctic Ocean). An ice core chronology of (236)U, (239)Pu, and (240)Pu concentrations, and atom ratios, measured by accelerator mass spectrometry in a 28.6m deep ice core from the Austfonna glacier at Nordaustlandet, Svalbard is presented. The ice core chronology corresponds to the period 1949 to 1999. The main sources of Pu and (236)U contamination in the Arctic were the atmospheric nuclear detonations in the period 1945 to 1980, as global fallout, and tropospheric fallout from the former Soviet Union test sites Novaya Zemlya and Semipalatinsk. Activity concentrations of (239+240)Pu ranged from 0.008 to 0.254 mBq cm(-2) and (236)U from 0.0039 to 0.053 μBq cm(-2). Concentrations varied in concordance with (137)Cs concentrations in the same ice core. In contrast to previous published results, the concentrations of Pu and (236)U were found to be higher at depths corresponding to the pre-moratorium period (1949 to 1959) than to the post-moratorium period (1961 and 1962). The (240)Pu/(239)Pu ratio ranged from 0.15 to 0.19, and (236)U/(239)Pu ranged from 0.18 to 1.4. The Pu atom ratios ranged within the limits of global fallout in the most intensive period of nuclear atmospheric testing (1952 to 1962). To the best knowledge of the authors the present work is the first publication on biogeochemical cycles with respect to (236)U concentrations and (236)U/(239)Pu atom ratios in the Arctic and in ice cores. Copyright © 2013 Elsevier B.V. All rights reserved.

  2. Inspection report of unauthorized possession and use of unsealed americium-241 and subsequent confiscation, J.C. Haynes Company, Newark, Ohio

    International Nuclear Information System (INIS)

    1985-11-01

    This US Nuclear Regulatory Commission report documents the circumstances surrounding the March 26, 1985, confiscation and subsequent decontamination activities related to the use of unauthorized quantities of americium-241 at the John C. Haynes Company (licensee) of Newark, Ohio. It focuses on the period from early February to July 26, 1985. The incident started when NRC Region III recieved information that John C. Haynes possessed unauthorized quantities of americium-241 and was conducting unauthorized activities (diamond irradiation). By July 26, 1985, the decontamination activities at the licensee's laboratory were concluded. The licensee's actions with diamond irradiation resulted in contamination in restricted and unrestricted areas of the facility. The confiscation and decontamination activities required the combined efforts of NRC, Federal Bureau of Investigation, US Department of Energy, Oak Ridge Associated Universities, the State of Ohio, and the US Environmental Protection Agency. The report describes the factual information and significant findings associated with the confiscation and decontamination activities

  3. 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)

    Paquet, F.

    1991-12-01

    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

  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)

    Paquet, F.

    1993-01-01

    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)

    Luisier, F.; Corcho Alvarado, J.A.; Froidevaux, P.; Steinmann, P.; Krachler, M.

    2009-01-01

    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 Eichrom R 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 Eichrom R 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 239 Pu in water samples at the μBq/l level, if ICP-SMS is used for the measurement. (author)

  6. {sup 236}U and {sup 129}I as tracers of water masses in the Arctic Ocean

    Energy Technology Data Exchange (ETDEWEB)

    Casacuberta, Nuria; Christl, Marcus; Vockenhuber, Christof; Synal, Hans-Arno [Laboratory of Ion Beam Physics, ETH-Zurich (Switzerland); Walther, Clemens [Institut fuer Radiooekologie und Strahlenschutz, Leibniz Universitaet Hannover (Germany); Loeff, Michiel van der [AWI-Geochemistry, Alfred Wegener Institut Fuer Polar und Meeresforshung, Bremerhaven (Germany); Masque, Pere [Institut de Ciencia i Tecnologia Ambientals, Universitat Autonoma de Barcelona, Bellaterra (Spain)

    2014-07-01

    Recently {sup 236}U attested to be a new transient oceanographic tracer: it is conservative in seawater and far from having reached steady state in the oceans. Its main sources in the North Atlantic are global fallout and European reprocessing plants. In this study, concentrations of {sup 236}U and {sup 129}I of eight deep profiles in the Arctic Ocean collected in 2011-2012 were determined with a compact ETH Zurich AMS system (TANDY). Results on {sup 236}U/{sup 238}U show a steep gradient, from the lowest ever-reported {sup 236}U/{sup 238}U atomic ratio in open ocean water (5±5) x 10{sup -12} up to (3700±80) x 10{sup -12}. Whereas the very low ratios are indicative for deep old waters, high ratios in shallow and surface waters show a clear signature of Atlantic Waters (AW) penetrating to the Arctic Ocean. The combination of {sup 236}U with {sup 129}I, both being released by the nuclear reprocessing plants of Sellafield and La Hague, with a distinct temporal input function, is used to estimate transit time of AW distributions in the Arctic Ocean.

  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)

    Nikiforova, A.; Kinova, L.; Peneva, C.; Taskaeva, I.; Petrova, P.

    2005-01-01

    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 K ozloduy . 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, H 2 C 2 O 4 , 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

  8. Transfer of plutonium and americium to grass vegetation as a function of radionuclide solid - solution portioning in soil

    International Nuclear Information System (INIS)

    Sokolik, G.; Ovsiannikova, S.; Ivanova, T.; Leinova, S.; Kimlenka, I.; Zakharenkov, V.; Zakharenkova, N.

    2004-01-01

    The aim of investigation is to determine the main parameters influencing the plutonium and americium migration in the soil plant system including concentration factor Cf and distribution coefficient K d . The C f factor characterising the ratio of radionuclide activity concentration in the plant specie (A p , Bq/kg) and root-inhabited layer of soil (A s , Bq/kg) has been used as a measure of biological availability of TUE. The K d coefficient estimating the ratio between radionuclide activity concentration in the equilibrium solid phase (A s.ph. ) and pore solution (A sol. , Bq/l) is considered as a measure of sorption ability of soil in respect to the radionuclide. The biological availability of 239,240 Pu and 241 Am for different grass species in various mineral and organic soils of natural and agrarian systems has been studied. The soils and grass vegetation were sampled in 1994 - 2001 in Bragin, Narovla, Khoiniki districts of Belarus (12 - 53 km from ChNPP). Since plant uptake depends primarily on radionuclide portion in the pore soil solution the proper solutions were separated from the soil samples of root-inhabited layer with the method of high-speed centrifugation. 239,240 Pu and 241 Am in the samples were determined radiochemically using alpha-spectrometer ALPHA-KING 676 A. Influence of composition of soil solution on the radionuclide soil plant transfer has been analysed. The interrelationships between the concentration factor (C f ), portion of radionuclide in the soil solution and coefficient K d have been considered. The results of investigations clearly demonstrated the dependence of TUE concentration factors for meadow sedge-herbaceous association of soil sorbing complex. As a rule, C f of americium is higher than that of plutonium. Differentiating of soils according to the C f value and the forecast of grass vegetation contamination by TUE in the different periods after catastrophe has been done. The levels of various soils contamination to receive

  9. Chronology of Pu isotopes and {sup 236}U in an Arctic ice core

    Energy Technology Data Exchange (ETDEWEB)

    Wendel, C.C., E-mail: cato.wendel@umb.no [Isotope Laboratory, Department of Plant and Environmental Sciences, Agricultural University of Norway, P.O. Box 5003, N-1432 Aas (Norway); Oughton, D.H., E-mail: deborah.oughton@umb.no [Isotope Laboratory, Department of Plant and Environmental Sciences, Agricultural University of Norway, P.O. Box 5003, N-1432 Aas (Norway); Lind, O.C., E-mail: ole-christian.lind@umb.no [Isotope Laboratory, Department of Plant and Environmental Sciences, Agricultural University of Norway, P.O. Box 5003, N-1432 Aas (Norway); Skipperud, L., E-mail: lindis.skipperud@umb.no [Isotope Laboratory, Department of Plant and Environmental Sciences, Agricultural University of Norway, P.O. Box 5003, N-1432 Aas (Norway); Fifield, L.K., E-mail: keith.fifield@anu.edu.au [Department of Nuclear Physics, Australian National University, Canberra ACT 0200 (Australia); Isaksson, E., E-mail: elisabeth.isaksson@npolar.no [Norwegian Polar Institute, Fram Centre, Hjalmar Johansens Gate 14, N9296 Tromsø (Norway); Tims, S.G., E-mail: steve.tims@anu.edu.au [Department of Nuclear Physics, Australian National University, Canberra ACT 0200 (Australia); Salbu, B., E-mail: brit.salbu@umb.no [Isotope Laboratory, Department of Plant and Environmental Sciences, Agricultural University of Norway, P.O. Box 5003, N-1432 Aas (Norway)

    2013-09-01

    In the present work, state of the art isotopic fingerprinting techniques are applied to an Arctic ice core in order to quantify deposition of U and Pu, and to identify possible tropospheric transport of debris from former Soviet Union test sites Semipalatinsk (Central Asia) and Novaya Zemlya (Arctic Ocean). An ice core chronology of {sup 236}U, {sup 239}Pu, and {sup 240}Pu concentrations, and atom ratios, measured by accelerator mass spectrometry in a 28.6 m deep ice core from the Austfonna glacier at Nordaustlandet, Svalbard is presented. The ice core chronology corresponds to the period 1949 to 1999. The main sources of Pu and {sup 236}U contamination in the Arctic were the atmospheric nuclear detonations in the period 1945 to 1980, as global fallout, and tropospheric fallout from the former Soviet Union test sites Novaya Zemlya and Semipalatinsk. Activity concentrations of {sup 239+240}Pu ranged from 0.008 to 0.254 mBq cm{sup −2} and {sup 236}U from 0.0039 to 0.053 μBq cm{sup −2}. Concentrations varied in concordance with {sup 137}Cs concentrations in the same ice core. In contrast to previous published results, the concentrations of Pu and {sup 236}U were found to be higher at depths corresponding to the pre-moratorium period (1949 to 1959) than to the post-moratorium period (1961 and 1962). The {sup 240}Pu/{sup 239}Pu ratio ranged from 0.15 to 0.19, and {sup 236}U/{sup 239}Pu ranged from 0.18 to 1.4. The Pu atom ratios ranged within the limits of global fallout in the most intensive period of nuclear atmospheric testing (1952 to 1962). To the best knowledge of the authors the present work is the first publication on biogeochemical cycles with respect to {sup 236}U concentrations and {sup 236}U/{sup 239}Pu atom ratios in the Arctic and in ice cores. - Highlights: • Concentrations and atom ratios of Pu and {sup 236}U determined in an Arctic ice core. • Concentrations of U and Pu found to be higher pre- than post-moratorium. • U and Pu concentrations

  10. Recommendation on changing interfaces of W-058 and W-236A

    International Nuclear Information System (INIS)

    Light, J.M.

    1994-01-01

    This position paper recommends changes to improve the interface between the Cross-Site Transfer System (Project W-058) and the Multi-Function Waste Tank Facility (Project W-236A) to handle planned waste retrieval and storage operations. Appendix A includes cost estimates and schedule impacts for each project. The cost estimates, schedule impacts, and this position paper will be the basis for writing a change request to formally implement these changes on Project W-236A and Project W-058/W-028. Recommendations are made on pipeline rerouting, pump and configuration, and flushing configuration

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

    International Nuclear Information System (INIS)

    Smith, B.F.; Gibson, R.R.; Jarvinen, G.D.; Jones, M.M.; Lu, M.T.; Robison, T.W.; Schroeder, N.C.; Stalnaker, N.

    1997-01-01

    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 241 Am(III) and 238 Pu(III)/(IV) at pH 4 to 6 and ionic strengths of 0.1 to 4

  12. The distribution and remobilisation of plutonium and americium in estuaries of the eastern Irish Sea: a review

    International Nuclear Information System (INIS)

    Toole, J.

    1993-01-01

    The plutonium and americium components in the authorised discharges from BNFL Sellafield are rapidly removed from Irish Sea seawater onto the particulate phase. These actinides tend to be concentrated in fine sediment deposits on the Irish Sea bed and in estuaries where fine sediment accumulates. This paper focuses on these estuarine areas and brings together the available data on the levels and distributions of Pu and Am within the estuarine sediments. The results from field and laboratory experiments which have been undertaken in order to determine the degree of Pu and Am remobilisation, and the mechanism responsible, are also reviewed. These sediment-associated actinides may undergo both chemical and physical remobilisation, leading to increased dissolved concentrations in low-salinity waters and to apparent losses from the estuary on the sediment phase under certain conditions. Saltmarsh sediments are demonstrated to be the most important reservoirs for Pu and Am. The radiological significance of the levels of Pu and Am found in these and in other sediments is summarised, by comparison with GDLs. The appropriateness of GDLs for assessing the radiological significance of Pu and Am in these saltmarsh sediments is discussed. A more site-specific assessment methodology is recommended. (author)

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

    International Nuclear Information System (INIS)

    Burns, P.A.; Cooper, M.B.; Lokan, K.H.; Wilks, M.J.; Williams, G.A.

    1995-01-01

    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)

  14. Characterization of a sealed Americium-Beryllium (AmBe) source by inductively coupled plasma mass spectrometry

    International Nuclear Information System (INIS)

    Sommers, J.; Jimenez, M.; Adamic, M.; Giglio, J.; Carney, K.

    2009-01-01

    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 uncertainties in the 'age' determination were ±4% 2σ. 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% (1σ). Source 2 had an Am-Be ratio of 9.81 ± 3.5% (1σ). In addition, the trace element content between the samples varied greatly. Significant differences were determined between Sources 1 and 2 for Sc, Sr, Y, Zr, Mo, Ba and W. (author)

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

    International Nuclear Information System (INIS)

    Geraldo, Bianca

    2012-01-01

    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)

  16. Vertical transport of particulate-associated plutonium and americium in the upper water column of the Northeast Pacific

    International Nuclear Information System (INIS)

    Fowler, S.W.; Ballestra, S.; La Rosa, J.; Fukai, R.

    1983-01-01

    Concentrations of plutonium (Pu) and americium (Am) were determined in seawater, suspended particulate matter, sediment trap samples, and biogenic material collected at the VERTEX I site in the North Pacific off central California. From a vertical profile taken over the upper 1500 m, the presence of sub-surface maxima of sup(239+240)Pu and 241 Am were identified between 100 to 750 m and 250 to 750 m, respectively. A large fraction (32%) of the filterable sup(239+240)Pu in surface waters was associated with cells during a phytoplankton bloom; Pu:Am activity ratios in surface water and the suspended particles indicated that Pu was concentrated by the cells to a greater degree than Am. However, similar measurements beneath the surface layer showed an overall enrichment of Am over Pu on fine suspended particles with depth. Freshly produced zooplankton fecal pellets and large, fast sinking particles collected in PITS contained relatively high concentrations of Pu and Am. Both transuranic concentrations in trapped particles and transuranic flux tended to increase with depth down to 750 m, suggesting that their scavenging is in the upper water column. Am appeared to be scavenged by sinking biogenic particles to a greater extent than Pu. The results are discussed. (author)

  17. MINERALIZATION OF THE HERBICIDE 2,3,6-TRICHLOROBENZOIC ACID BY A COCULTURE OF ANAEROBIC AND AEROBIC-BACTERIA

    NARCIS (Netherlands)

    GERRITSE, J; GOTTSCHAL, JC

    1992-01-01

    Bacteria from an anaerobic enrichment reductively removed chlorine from the ortho- position of 2,3,6-trichlorobenzoic acid (2,3,6-TBA) producing 2,5-dichlorobenzoate (2,5-DBA). The strictly aerobic bacterium Pseudomonas aeruginosa JB2 subsequently used 2,5-DBA as a growth substrate in the presence

  18. HEAT TRANSFER EVALUATION OF HFC-236FA IN CONDENSATION AND EVAPORATION

    Science.gov (United States)

    The report gives results of an evaluation of the shell-side heat transfer performance of hydrofluorocarbon (HFC)-236fa, which is considered to be a potential substitute for chlorofluorocarbon (CFC)-114 in Navy shipboard chillers, for both conventional finned [1024- and 1575-fpm (...

  19. HEAT TRANSFER EVALUATION OF HFC-236EA WITH HIGH PERFORMANCE ENHANCED TUBES IN CONDENSATION AND EVAPORATION

    Science.gov (United States)

    The report gives results of an evaluation of the heat transfer performance of pure hydrofluorocarbon (HFC)-236ea for high performance enhanced tubes which had not been previously used in Navy shipboard chillers. Shell-side heat transfer coefficient data are presented for condensa...

  20. HEAT TRANSFER EVALUATION OF HFC-236EA AND CFC-114 IN CONDENSATION AND EVAPORATION

    Science.gov (United States)

    The report gives results of a heat transfer evaluation of the refrigerants hexafluoropropane (HFC-236ea) and 1,1,2,2-dichloro-tetrafluoroethane (CFC-114). (NOTE: With the mandatory phase-out of chlorofluorocarbons (CFCs), as dictated by the Montreal Protocol and Clean Air Act Ame...

  1. 49 CFR 236.335 - Dogs, stops and trunnions of mechanical locking.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Dogs, stops and trunnions of mechanical locking..., AND APPLIANCES Interlocking Rules and Instructions § 236.335 Dogs, stops and trunnions of mechanical locking. Driving pieces, dogs, stops and trunnions shall be rigidly secured to locking bars. Swing dogs...

  2. 49 CFR 236.207 - Electric lock on hand-operated switch; control.

    Science.gov (United States)

    2010-10-01

    ..., AND APPLIANCES Automatic Block Signal Systems Standards § 236.207 Electric lock on hand-operated switch; control. Electric lock on hand-operated switch shall be controlled so that it cannot be unlocked... 49 Transportation 4 2010-10-01 2010-10-01 false Electric lock on hand-operated switch; control...

  3. 48 CFR 652.236-71 - Foreign Service Buildings Act, as Amended.

    Science.gov (United States)

    2010-10-01

    ... 48 Federal Acquisition Regulations System 4 2010-10-01 2010-10-01 false Foreign Service Buildings....236-71 Foreign Service Buildings Act, as Amended. As prescribed in 636.570(a), insert the following provision: Foreign Service Buildings Act, as Amended (APR 2004) (a) This solicitation is subject to Section...

  4. 48 CFR 852.236-72 - Performance of work by the contractor.

    Science.gov (United States)

    2010-10-01

    ... 48 Federal Acquisition Regulations System 5 2010-10-01 2010-10-01 false Performance of work by the....236-72 Performance of work by the contractor. As prescribed in 836.501, insert the following clause: Performance of Work by the Contractor (JUL 2002) The clause entitled “Performance of Work by the Contractor...

  5. 48 CFR 52.236-1 - Performance of Work by the Contractor.

    Science.gov (United States)

    2010-10-01

    ... 48 Federal Acquisition Regulations System 2 2010-10-01 2010-10-01 false Performance of Work by the....236-1 Performance of Work by the Contractor. As prescribed in 36.501(b), insert the following clause... the work and customary or necessary specialty subcontracting (see 36.501(a)).] Performance of Work by...

  6. 49 CFR 236.206 - Battery or power supply with respect to relay; location.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Battery or power supply with respect to relay..., AND APPLIANCES Automatic Block Signal Systems Standards § 236.206 Battery or power supply with respect to relay; location. The battery or power supply for each signal control relay circuit, where an open...

  7. 49 CFR 236.308 - Mechanical or electric locking or electric circuits; requisites.

    Science.gov (United States)

    2010-10-01

    ..., AND APPLIANCES Interlocking Standards § 236.308 Mechanical or electric locking or electric circuits; requisites. Mechanical or electric locking or electric circuits shall be installed to prevent signals from... 49 Transportation 4 2010-10-01 2010-10-01 false Mechanical or electric locking or electric...

  8. 48 CFR 236.271 - Cost-plus-fixed-fee contracts.

    Science.gov (United States)

    2010-10-01

    ... 48 Federal Acquisition Regulations System 3 2010-10-01 2010-10-01 false Cost-plus-fixed-fee... CONTRACTS Special Aspects of Contracting for Construction 236.271 Cost-plus-fixed-fee contracts. Annual military construction appropriations acts restrict the use of cost-plus-fixed-fee contracts (see 216.306(c...

  9. 49 CFR 236.22 - Semaphore signal arm; clearance to other objects.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Semaphore signal arm; clearance to other objects... Rules and Instructions: All Systems Roadway Signals and Cab Signals § 236.22 Semaphore signal arm; clearance to other objects. At least one-half inch clearance shall be provided between semaphore signal arm...

  10. 48 CFR 53.236-2 - Architect-engineer services (SF's 252 and 330).

    Science.gov (United States)

    2010-10-01

    ... 48 Federal Acquisition Regulations System 2 2010-10-01 2010-10-01 false Architect-engineer... ACQUISITION REGULATION (CONTINUED) CLAUSES AND FORMS FORMS Prescription of Forms 53.236-2 Architect-engineer...-engineer and related services: (a) SF 252 (Rev. 10/83), Architect-Engineer Contract. SF 252 is prescribed...

  11. 17 CFR 230.236 - Exemption of shares offered in connection with certain transactions.

    Science.gov (United States)

    2010-04-01

    ... Exemptions § 230.236 Exemption of shares offered in connection with certain transactions. Shares of stock or... securities in lieu of issuing fractional shares, script certificates or order forms, in connection with a stock dividend, stock split, reverse stock split, conversion, merger or similar transaction, shall be...

  12. 49 CFR 236.925 - Training specific to control office personnel.

    Science.gov (United States)

    2010-10-01

    ... applicable to the train control system, including provision for movement and protection of roadway workers... 49 Transportation 4 2010-10-01 2010-10-01 false Training specific to control office personnel. 236... INSTALLATION, INSPECTION, MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES...

  13. 49 CFR 236.1045 - Training specific to office control personnel.

    Science.gov (United States)

    2010-10-01

    ... control system, including provision for movement and protection of roadway workers, unequipped trains... 49 Transportation 4 2010-10-01 2010-10-01 false Training specific to office control personnel. 236... INSTALLATION, INSPECTION, MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES...

  14. 24 CFR 1000.236 - What are eligible administrative and planning expenses?

    Science.gov (United States)

    2010-04-01

    ... administrative management; (2) Coordination monitoring and evaluation; (3) Preparation of the IHP including data... 24 Housing and Urban Development 4 2010-04-01 2010-04-01 false What are eligible administrative...) § 1000.236 What are eligible administrative and planning expenses? (a) Eligible administrative and...

  15. Radioisotope dilution analyses of geological samples using 236U and 229Th

    Science.gov (United States)

    Rosholt, J.N.

    1984-01-01

    The use of 236U and 229Th in alpha spectrometric measurements has some advantages over the use of other tracers and measurement techniques in isotope dilution analyses of most geological samples. The advantages are: (1) these isotopes do not occur in terrestrial rocks, (2) they have negligible decay losses because of their long half lives, (3) they cause minimal recoil contamination to surface-barrier detectors, (4) they allow for simultaneous determination of the concentration and isotopic composition of uranium and thorium in a variety of sample types, and (5) they allow for simple and constant corrections for spectral inferences, 0.5% of the 238U activity is subtracted for the contribution of 235U in the 236U peak and 1% of the 229Th activity is subtracted from the 230Th activity. Disadvantages in using 236U and 229Th are: (1) individual separates of uranium and thorium must be prepared as very thin sources for alpha spectrometry, (2) good resolution in the spectrometer system is required for thorium isotopic measurements where measurement times may extend to 300 h, and (3) separate calibrations of the 236U and 229Th spike solution with both uranium and thorium standards are required. The use of these tracers in applications of uranium-series disequilibrium studies has simplified the measurements required for the determination of the isotopic composition of uranium and thorium because of the minimal corrections needed for alpha spectral interferences. ?? 1984.

  16. Isotope shift of 234U, 236U, 238U in U I

    International Nuclear Information System (INIS)

    Gagne, J.M.; Nguyen Van, S.; Saint-Dizier, J.P.; Pianarosa, P.

    1976-01-01

    New and very accurate data of isotope shifts and relative isotope shifts in 234 U, 236 U, 238 U are presented. The invariance of the relative isotope shift, for the transitions we have investigated, supports the hypothesis that the so called specific mass effect is negligible in uranium

  17. Radioisotope dilution analyses of geological samples using 236U and 229Th

    International Nuclear Information System (INIS)

    Rosholt, J.N.

    1984-01-01

    The use of 236 U and 229 Th in alpha spectrometric measurements has some advantages over the use of other tracers and measurement techniques in isotope dilution analyses of most geological samples. The advantages are: 1) these isotopes do not occur in terrestrial rocks, 2) they have negligible decay losses because of their long half lives, 3) they cause minimal recoil contamination to surface-barrier detectors, 4) they allow for simultaneous determination of the concentration and isotopic composition of uranium and thorium in a variety of sample types, and 5) they allow for simple and constant corrections for spectral interferences, 0.5% of the 238 U activity is subtracted for the contribution of 235 U in the 236 U peak and 1% of the 229 Th activity is subtracted from the 230 Th activity. Disadvantages in using 236 U and 229 Th are: 1) individual separates of uranium and thorium must be prepared as very thin sources for alpha spectrometry, 2) good resolution in the spectrometer system is required for thorium isotopic measurements where measurement times may extend to 300 h, and 3) separate calibrations of the 236 U and 229 Th spike solution with both uranium and thorium standards are required. The use of these tracers in applications of uranium-series disequilibrium studies has simplified the measurements required for the determination of the isotopic composition of uranium and thorium because of the minimal corrections needed for alpha spectral interferences. (orig.)

  18. Experimental study of Americium-241 biokinetics in Homarus Gammarus lobster. Analysis of the accumulation and detoxication mechanisms at the sub-cellular level; Etude experimentale des biocinetiques de l`americium-241 chez le homard homarus gammarus. Analyse des mecanismes d`accumulation et de detoxication au niveau subcellulaire

    Energy Technology Data Exchange (ETDEWEB)

    Paquet, F

    1991-12-01

    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.

  19. 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

    International Nuclear Information System (INIS)

    Runde, W.; Kim, J.I.

    1994-09-01

    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 2 -free atmosphere and 10 -2 atm CO 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.) [de

  20. A year-by-year record of 236-U/238-U in coral as a step towards establishing 236-U from nuclear weapons testing fall-out as oceanic tracer

    Energy Technology Data Exchange (ETDEWEB)

    Winkler, Stephan; Steier, Peter [University of Vienna, Faculty of Physics, Vienna (Austria); Carilli, Jessica [Australian Nuclear Science and Technology Organisation, Lucas Heights (Australia)

    2012-07-01

    Since uranium is known to behave conservatively in ocean waters, 236-U has great potential in application as oceanic tracer. 236-U (t1/2=23.4 Ma) was introduced into the oceans by atmospheric nuclear weapon testing with amount estimates ranging from 700 kg to 1500 kg. Thus a resulting initial average 236-U/238-U ratio of at least 5e-9 is expected for an oceanic mixed layer depth of 100 m. This ratio is already higher than the natural pre-nuclear background, which is expected to be at 10e-14 levels. Even the elevated ratios of global stratospheric fall-out are beyond the capabilities of ICPMS and TIMS methods. However, the exceptional sensitivity and ultra-low background for 236-U of the Vienna Environmental Research Accelerator's Accelerator Mass Spectrometry system allows us to measure down to 10-13 detection limits. We present a year-by-year record of 236-U/238-U for a Caribbean coral core covering years 1944 to 2006, thus allowing to us put constraints on the oceanic input of 236-U by atmospheric testing. Moreover modeling of the results also demonstrates the capabilities of 236-U as oceanic tracer.

  1. Transfer across the human gut of environmental plutonium, americium, cobalt, caesium and technetium: studies with cockles (Cerastoderma edule) from the Irish Sea

    International Nuclear Information System (INIS)

    Hunt, G.J.

    1998-01-01

    Our previous studies have indicated lower values of the gut transfer factor ('f L values') for plutonium and americium in winkles (Littorina littorea) than adopted by ICRP. The present study was undertaken primarily to investigate whether this observation extends to other species. Samples of cockles (Cerastoderma edule) from Ravenglass, Cumbria were eaten by volunteers who provided 24 samples of urine and faeces. Urine samples indicated f L values for cockles which were higher than for winkles; for plutonium these ranged overall up to 7x10 -4 with an arithmetic mean in the range (2-3)x10 -4 , and for americium up to 2.6x10 -4 with an arithmetic mean of 1.2x10 -4 . Limited data based on volunteers eating cockles from the Solway suggest that f L values for americium may be greater at distance from Sellafield. The measured values compare with 5x10 -4 used by the ICRP for environmental forms of both elements, which would appear to provide adequate protection when calculating doses from Cumbrian cockles. Data for other nuclides were obtained by analysing faecal samples from the volunteers who ate the Ravenglass cockles. Cobalt-60 showed an f L value in the region of 0.2, twice the value currently used by ICRP. For 137 Cs, variabilities were indicated in the range 0.08 to 0.43, within the ICRP value of f L =1.0. Technetium-99 gave f L values up to about 0.6, in reasonable conformity with the ICRP value of 0.5. (author)

  2. An experimental study of americium-241 biokinetics in the Lobster Homarus Gammarus. Analysis of the accumulation/storage and detoxification processes at the subcellular level; Etude experimentale des biocinetiques de l`americium-241 chez le homard homarus gammarus. Analyse des mecanismes d`accumulation et de detoxication au niveau subcellulaire

    Energy Technology Data Exchange (ETDEWEB)

    Paquet, F

    1993-01-01

    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 {sup 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.

  3. 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)

  4. Picomolar traces of americium(III) introduce drastic changes in the structural chemistry of terbium(III). A break in the ''gadolinium break''

    Energy Technology Data Exchange (ETDEWEB)

    Welch, Jan M. [TU Wien, Atominstitut, Vienna (Austria); Mueller, Danny; Knoll, Christian; Wilkovitsch, Martin; Weinberger, Peter [TU Wien, Institute of Applied Synthetic Chemistry, Vienna (Austria); Giester, Gerald [University of Vienna, Institute of Mineralogy and Crystallography, Vienna (Austria); Ofner, Johannes; Lendl, Bernhard [TU Wien, Institute of Chemical Technologies and Analytics, Vienna (Austria); Steinhauser, Georg [Leibniz Universitaet Hannover, Institute of Radioecology and Radiation Protection (Germany)

    2017-10-16

    The crystallization of terbium 5,5{sup '}-azobis[1H-tetrazol-1-ide] (ZT) in the presence of trace amounts (ca. 50 Bq, ca. 1.6 pmol) of americium results in 1) the accumulation of the americium tracer in the crystalline solid and 2) a material that adopts a different crystal structure to that formed in the absence of americium. Americium-doped [Tb(Am)(H{sub 2}O){sub 7}ZT]{sub 2} ZT.10 H{sub 2}O is isostructural to light lanthanide (Ce-Gd) 5,5{sup '}-azobis[1H-tetrazol-1-ide] compounds, rather than to the heavy lanthanide (Tb-Lu) 5,5{sup '}-azobis[1H-tetrazol-1-ide] (e.g., [Tb(H{sub 2}O){sub 8}]{sub 2}ZT{sub 3}.6 H{sub 2}O) derivatives. Traces of Am seem to force the Tb compound into a structure normally preferred by the lighter lanthanides, despite a 10{sup 8}-fold Tb excess. The americium-doped material was studied by single-crystal X-ray diffraction, vibrational spectroscopy, radiochemical neutron activation analysis, and scanning electron microscopy. In addition, the inclusion properties of terbium 5,5{sup '}-azobis[1H-tetrazol-1-ide] towards americium were quantified, and a model for the crystallization process is proposed. (copyright 2017 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

  5. Observations on the redistribution of plutonium and americium in the Irish Sea sediments, 1978 to 1996: concentrations and inventories

    International Nuclear Information System (INIS)

    Kershaw, P.J.; Denoon, D.C.; Woodhead, D.S.

    1999-01-01

    The distribution of plutonium and americium in the sub-tidal sediments of the Irish Sea is described following major surveys in 1978, 1983, 1988 and 1995. Concentrations in surface sediments have declined near the source at Sellafield since 1988. Time-series of inter-tidal surface sediment concentrations are presented from 1977 onwards, revealing the importance of sediment reworking and transport in controlling the evolution of the environmental signal. The surface and near-surface sediments, in the eastern Irish Sea 'mud-patch', are generally well mixed with respect to Pu (α) and 241 Am distributions but show increasing variability with depth - up to 4 orders of magnitude in concentration. The inventories of 239,240 Pu and 241 Am in the sub-tidal sediments have been estimated and compared with the reported decay-corrected discharges. These amounted to 360 and 545 TBq respectively, in 1995, about 60% of the total decay-corrected discharge. Part of the unaccounted fraction may be due to unrepresentative sampling of the seabed. It is speculated that some tens of TBq of plutonium and 241 Am reside undetected in the large volumes of coarse-grained, sub-tidal and inter-tidal sediment which characterise much of the Irish Sea. This has been due to the inability of the available corers to penetrate to the base of contamination in these mobile sediments. Further observations are needed to verify and quantify the missing amount. A budget of plutonium-α and 241 Am has been estimated based on published observations in the three main compartments: water column, sub-tidal and inter-tidal sediments. This amounts to 460-540 TBq and 575-586 TBq respectively, or 64-75% and 60-61%, of the decay-corrected reported discharge. (Copyright (c) 1999 Elsevier Science B.V., Amsterdam. All rights reserved.)

  6. Measurement of total alpha activity of neptunium, plutonium, and americium in highly radioactive Hanford waste by iron hydroxide precipitation and 2-heptanone solvent extraction

    International Nuclear Information System (INIS)

    Maiti, T.C.; Kaye, J.H.

    1992-06-01

    An improved method has been developed to concentrate the major alpha-emitting actinide elements neptunium, plutonium, and americium from samples with high salt content such as those resulting from efforts to characterize Hanford storage tank waste. Actinide elements are concentrated by coprecipitation of their hydroxides using iron carrier. The iron is removed by extraction from 8M HCI with 2-heptanone. The actinide elements remain in the aqueous phase free from salts, iron, and long-lived fission products. Recoveries averaged 98 percent

  7. Neutron widths for 236U from high resolution transmission measurements at a 100M flightpath

    International Nuclear Information System (INIS)

    Carraro, G.; Brusegan, A.

    1975-01-01

    A series of neutron transmission measurements has been performed on 236 U aiming at a determination of the resonance parameters and their statistical properties. The analysis range covered neutron energies from 40eV to 4.1 keV. The experiments were carried out at about 100 m flightpath of the 80 MeV electron linear accelerator of CBNM using a 10 B slab-NaI detector and 2 236 U-oxyde samples on loan from the USAEC. A table displays the details of 6 experimental runs, 3 of which were arranged in such a way that the effect of the 235 U and 238 U impurities in the sample on the transmission was automatically compensated

  8. Synthesis of zirconia sol stabilized by trivalent cations (yttrium and neodymium or americium): a precursor for Am-bearing cubic stabilized zirconia.

    Science.gov (United States)

    Lemonnier, Stephane; Grandjean, Stephane; Robisson, Anne-Charlotte; Jolivet, Jean-Pierre

    2010-03-07

    Recent concepts for nuclear fuel and targets for transmuting long-lived radionuclides (minor actinides) and for the development of innovative Gen-IV nuclear fuel cycles imply fabricating host phases for actinide or mixed actinide compounds. Cubic stabilized zirconia (Zr, Y, Am)O(2-x) is one of the mixed phases tested in transmutation experiments. Wet chemical routes as an alternative to the powder metallurgy are being investigated to obtain the required phases while minimizing the handling of contaminating radioactive powder. Hydrolysis of zirconium, neodymium (a typical surrogate for americium) and yttrium in aqueous media in the presence of acetylacetone was firstly investigated. Progressive hydrolysis of zirconium acetylacetonate and sorption of trivalent cations and acacH on the zirconia particles led to a stable dispersion of nanoparticles (5-7 nm) in the 6-7 pH range. This sol gels with time or with temperature. The application to americium-containing solutions was then successfully tested: a stable sol was synthesized, characterized and used to prepare cubic stabilized zirconia (Zr, Y, Am)O(2-x).

  9. Study of 236U/238U ratio at CIRCE using a 16-strip silicon detector with a TOF system

    Science.gov (United States)

    De Cesare, M.; De Cesare, N.; D'Onofrio, A.; Gialanella, L.; Terrasi, F.

    2015-04-01

    Accelerator Mass Spectrometry (AMS) is presently the most sensitive technique for the measurement of long-lived actinides, e.g. 236U and xPu isotopes. A new actinide AMS system, based on a 3-MV pelletron tandem accelerator, is operated at the Center for Isotopic Research on Cultural and Environmental Heritage (CIRCE) in Caserta, Italy. In this paper we report on the procedure adopted to increase the 236U abundance sensitivity as low as possible. The energy and position determinations of the 236U ions, using a 16-strip silicon detector have been obtained. A 236U/238U isotopic ratio background level of about 2.9×10-11 was obtained, summing over all the strips, using a Time of Flight-Energy (TOF-E) system with a 16-strip silicon detector (4.9×10-12 just with one strip).

  10. Study of 236U/238U ratio at CIRCE using a 16-strip silicon detector with a TOF system

    Directory of Open Access Journals (Sweden)

    De Cesare M.

    2015-01-01

    Full Text Available Accelerator Mass Spectrometry (AMS is presently the most sensitive technique for the measurement of long-lived actinides, e.g. 236U and xPu isotopes. A new actinide AMS system, based on a 3-MV pelletron tandem accelerator, is operated at the Center for Isotopic Research on Cultural and Environmental Heritage (CIRCE in Caserta, Italy. In this paper we report on the procedure adopted to increase the 236U abundance sensitivity as low as possible. The energy and position determinations of the 236U ions, using a 16-strip silicon detector have been obtained. A 236U/238U isotopic ratio background level of about 2.9×10−11 was obtained, summing over all the strips, using a Time of Flight-Energy (TOF-E system with a 16-strip silicon detector (4.9×10−12 just with one strip.

  11. Investigation of the separation of americium(III) and europium(III) by high-speed countercurrent chromatography

    International Nuclear Information System (INIS)

    Wu, J.F.; Jin, Y.R.; Xu, Q.C.; Wang, S.L.; Zhang, L.X.

    2005-01-01

    The long-lived actinides are the important elements in the radioactive waste ;disposal. Because the ions semi diameter and chemical properties of trivalent actinides(III) and trivalent lanthanides(III) are very similar, the separation between them is very difficult. Yang Yu-Sheng put forward the actinides(III) are softer acid than the lanthanides(III), so the actinides(III) are more easily extracted by the soft extractant contain sulfur or nitrogen than the lanthanides(III). Some research have been done on the separation between actinides(III) and lanthanides(III) using the extractants contain sulfur or nitrogen. The results show that satisfactory separation efficiency was gained. Countercurrent Chromatography (CCC) have many specific advantages, such as free from solid support, permit large sample volume and high flow rate, which is useful in the preconcentration of inorganic solute and inorganic preparation. Some studies were done on the separation of lanthanides or-other inorganic elements by HSCCC, the high-purity reagents prepared by HSCCC or CPC turned out to be successful. In present paper, the investigation of separation between Americium (III) and Euricium (III) by High-Speed Countercurrent Chromatography (HSCCC) were made. The extractant used in the work was prepared by ourselves, which is of the soft extractant contrain sulfur. The effects of separation condition on the separation efficiency of Am and Eu by HSCCC were investigated using dichlorophenyl dithiophosphinic acid in xylene as the stationary phase and 0.1 mol/L NaClO4 as mobile phase, respectively. The results show that mutual separation between Am and Eu can be accomplished. The separation factor increases with the increasing of the concentration of extractant and the pH value of the mobile phase, further more, minishing the flow rate of the mobile phase can also improves the separation efficiency between Am and Eu. The nearly base separation was gained when the flow rate is 0.35 ml/min, the

  12. Acinetobacter phage genome is similar to Sphinx 2.36, the circular DNA copurified with TSE infected particles.

    Science.gov (United States)

    Longkumer, Toshisangba; Kamireddy, Swetha; Muthyala, Venkateswar Reddy; Akbarpasha, Shaikh; Pitchika, Gopi Krishna; Kodetham, Gopinath; Ayaluru, Murali; Siddavattam, Dayananda

    2013-01-01

    While analyzing plasmids of Acinetobacter sp. DS002 we have detected a circular DNA molecule pTS236, which upon further investigation is identified as the genome of a phage. The phage genome has shown sequence similarity to the recently discovered Sphinx 2.36 DNA sequence co-purified with the Transmissible Spongiform Encephalopathy (TSE) particles isolated from infected brain samples collected from diverse geographical regions. As in Sphinx 2.36, the phage genome also codes for three proteins. One of them codes for RepA and is shown to be involved in replication of pTS236 through rolling circle (RC) mode. The other two translationally coupled ORFs, orf106 and orf96, code for coat proteins of the phage. Although an orf96 homologue was not previously reported in Sphinx 2.36, a closer examination of DNA sequence of Sphinx 2.36 revealed its presence downstream of orf106 homologue. TEM images and infection assays revealed existence of phage AbDs1 in Acinetobacter sp. DS002.

  13. The MARINE experiment: Irradiation of sphere-pac fuel and pellets of UO{sub 2−x} for americium breeding blanket concept

    Energy Technology Data Exchange (ETDEWEB)

    D' Agata, E., E-mail: elio.dagata@ec.europa.eu [European Commission, Joint Research Centre, Institute for Energy and Transport, P.O. Box 2, NL-1755 ZG Petten (Netherlands); Hania, P.R. [Nuclear Research and Consultancy Group, P.O. Box 25, NL-1755 ZG Petten (Netherlands); Freis, D.; Somers, J. [European Commission, Joint Research Centre, Institute for Transuranium Elements, P.O. Box 2340, D-76125 Karlsruhe (Germany); Bejaoui, S. [Commissariat à l’Energie Atomique et aux Energies Alternatives, DEN/DEC, F-13108 St. Paul lez Durance Cedex (France); Charpin, F.F.; Baas, P.J.; Okel, R.A.F.; Til, S. van [Nuclear Research and Consultancy Group, P.O. Box 25, NL-1755 ZG Petten (Netherlands); Lapetite, J.-M. [European Commission, Joint Research Centre, Institute for Energy and Transport, P.O. Box 2, NL-1755 ZG Petten (Netherlands); Delage, F. [Commissariat à l’Energie Atomique et aux Energies Alternatives, DEN/DEC, F-13108 St. Paul lez Durance Cedex (France)

    2017-01-15

    Highlights: • MARINE is designed to check the behaviour of MABB sphere-pac concept. • MABB sphere-pac are compared with MABB pellet. • Swelling and helium release behaviour will be the main output of the experiment. • An experiment to check sphere-pac MADF fuel behaviour has been already performed. - Abstract: Americium is a strong contributor to the long term radiotoxicity of high activity nuclear waste. Transmutation by irradiation in nuclear reactors of long-lived nuclides like {sup 241}Am is therefore an option for the reduction of radiotoxicity and heat production of waste packages to be stored in a repository. The MARINE irradiation experiment is the latest of a series of European experiments on americium transmutation (e.g. EFTTRA-T4, EFTTRA-T4bis, HELIOS, MARIOS, SPHERE) performed in the High Flux Reactor (HFR). The MARINE experiment is developed and carried out in the framework of the collaborative research project PELGRIMM of the EURATOM 7th Framework Programme (FP7). During the past years of experimental works in the field of transmutation and tests of innovative nuclear fuels, the release or trapping of helium as well as swelling have been shown to be the key issues for the design of such kind of fuel both as drivers and even more for Am-bearing blanket targets (due to the higher Am contents). The main objective of the MARINE experiment is to study the in-pile behaviour of uranium oxide fuel containing 13% of americium and to compare the behaviour of sphere-pac versus pellet fuel, in particular the role of microstructure and temperature on fission gas release and He on fuel swelling. The MARINE experiment will be irradiated in 2016 in the HFR in Petten (The Netherlands) and is expected to be completed in spring 2017. This paper discusses the rationale and objective of the MARINE experiment and provides a general description of its design for which some innovative features have been adopted.

  14. Inhaled americium dioxide

    International Nuclear Information System (INIS)

    Park, J.F.

    1982-01-01

    This project includes experiments to determine the effects of Zn-DTPA therapy on the retention, translocation and biological effects of inhaled 241 AmO 2 . Beagle dogs that received inhalation exposure to 241 AmO 2 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 241 Am. Another group of dogs that received inhalation exposure to 241 AmO 2 and were treated daily with Zn-DTPA had initial pulmonary deposition of 19 to 26 μCi 241 Am. These dogs did not develop respiratory insufficiency, and hematologic and clinical chemistry changes were less severe than in the non-DTPA-treated dogs

  15. Americium-241 Decorporation Model

    Science.gov (United States)

    2014-10-01

    non- pyrogenic ampoules suitable for intravenous administration (FDA 2004, Hameln 2004). This is a standard formulation, which is a fixed parameter...4.4.6. Toxicity/Side Effects Treatment with DTPA can deplete endogenous metals, which is why the Zn salt is preferred for long-term treatment...However, other endogenous metals may be depleted if treatment spans several months. During prolonged treatments serum levels of essential metals should be

  16. 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)

    Perrier, T.

    2004-06-01

    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 241 Am 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. 241 Am remobilization has been studied at the laboratory using leaching experiments performed in controlled conditions on reworked calcareous soils artificially contaminated with 241 Am. 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, Fe tot , organic acids, 241 Am) and its bacterial biomass content too. The overall results indicate that 241 Am 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 241 Am corresponds to a solid/liquid coefficient of partition (K d ) of about 10 5 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 241 Am 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 241 Am released after the dissolution of the carrying phases. Finally, the colloidal transport of 241 Am has been systematically observed in a limited but

  17. Artificial radionuclides in the Northern European Marine Environment. Distribution of radiocaesium, plutonium and americium in sea water and sediments in 1995

    International Nuclear Information System (INIS)

    Groettheim, Siri

    2000-01-01

    This study considers the distribution of radiocaesium, plutonium and americium in the northern marine environment. The highest radiocaesium activity in sea water was observed in Skagerrak, 26 Bq/m 3 , and in surface sediments in the Norwegian Sea, 60 Bq/kg. These enhanced levels were related to Chernobyl. The highest 239,240Pu activity in surface water was measured in the western North Sea, 66 mBq/m 3 . In sea water, sub-surface maxima were observed at several locations with an 239,240Pu activity up to 160 mBq/m 3 , and were related to Sellafield. With the exception to the North Sea, surface sediments reflected Pu from global fallout from weapons tests only. (author)

  18. 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)

    Louwrier, K.P.; Richter, K.

    1976-01-01

    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 239 Pu containing 8-12% 240 Pu (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 241 Am 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 241 Am, 243 Am and 244 Cm. 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 241 Am 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)

  19. AMS measurements of global fallout U-236 and Pu in an ombrotrophic peat profile: evidence for their post depositional migration

    Energy Technology Data Exchange (ETDEWEB)

    Quinto, Francesca; Hrnecek, Erich; Krachler, Michael [European Commission Joint Research Centre, Institute for Transuranium Elements, P.O. Box 2340, 76125 Karlsruhe (Germany); Shotyk, William [Department of Renewable Resources, University of Alberta, 839 General Services Building, Edmonton, AB (Canada); Steier, Peter; Winkler, Stephan; Golser, Robin [VERA Laboratory, Faculty of Physics, University of Vienna, Waehringer Strasse 17, A-1090 Vienna (Austria)

    2014-07-01

    U-236, Pu-239, Pu-240, Pu-241 and Pu-242 were analysed in an ombrotrophic peat core representing the last 80 years of atmospheric deposition. The determination of these isotopes at femtogram and attogram levels was possible by using ultra-clean laboratory procedures and accelerator mass spectrometry. Since the Pu isotopic composition characteristic for global fallout, as well as anthropogenic U-236, were identified in peat samples pre-dating the period of atmospheric atom bomb testing, migration of Pu and U within the peat profile is clearly indicated. The vertical profile of the U-236/U-238 isotopic ratio represents the first observation of the U-236 bomb peak in a terrestrial environment. Comparing the abundances of the global fallout derived U-236 and Pu-239 along the peat core, the post depositional migration of plutonium exceeds that of uranium. These results highlight, for the first time, the mobility of Pu and U in a peat bog with implications for their migration in other acidic, organic rich environments.

  20. The 236U neutron capture cross-section measured at the n_TOF CERN facility

    Directory of Open Access Journals (Sweden)

    Mastromarco M.

    2017-01-01

    Full Text Available The 236U isotope plays an important role in nuclear systems, both for future and currently operating ones. The actual knowledge of the capture reaction of this isotope is satisfactory in the thermal region, but it is considered insufficient for Fast Reactor and ADS applications. For this reason the 236U(n, γ reaction cross-section has been measured for the first time in the whole energy region from thermal energy up to 1 MeV at the n_TOF facility with two different detection systems: an array of C6D6 detectors, employing the total energy deposited method, and a FX1 total absorption calorimeter (TAC, made of 40 BaF2 crystals. The two n_TOF data sets agree with each other within the statistical uncertainty in the Resolved Resonance Region up to 800 eV, while sizable differences (up to ≃ 20% are found relative to the current evaluated data libraries. Moreover two new resonances have been found in the n_TOF data. In the Unresolved Resonance Region up to 200 keV, the n_TOF results show a reasonable agreement with previous measurements and evaluated data.

  1. Towards saturation of the electron-capture delayed fission probability: The new isotopes 240Es and 236Bk

    Directory of Open Access Journals (Sweden)

    J. Konki

    2017-01-01

    Full Text Available The new neutron-deficient nuclei 240Es and 236Bk were synthesised at the gas-filled recoil separator RITU. They were identified by their radioactive decay chains starting from 240Es produced in the fusion–evaporation reaction 209Bi(34S,3n240Es. Half-lives of 6(2s and 22−6+13s were obtained for 240Es and 236Bk, respectively. Two groups of α particles with energies Eα=8.19(3MeV and 8.09(3MeV were unambiguously assigned to 240Es. Electron-capture delayed fission branches with probabilities of 0.16(6 and 0.04(2 were measured for 240Es and 236Bk, respectively. These new data show a continuation of the exponential increase of ECDF probabilities in more neutron-deficient isotopes.

  2. 236U and 239,240Pu ratios from soils around an Australian nuclear weapons test site

    International Nuclear Information System (INIS)

    Tims, S.G.; Froehlich, M.B.; Fifield, L.K.; Wallner, A.; De Cesare, M.

    2016-01-01

    The isotopes 236 U, 239 Pu and 240 Pu are present in surface soils as a result of global fallout from nuclear weapons tests carried out in the 1950's and 1960's. These isotopes potentially constitute artificial tracers of recent soil erosion and sediment movement. Only Accelerator Mass Spectrometry has the requisite sensitivity to measure all three isotopes at these environmental levels. Coupled with its relatively high throughput capabilities, this makes it feasible to conduct studies of erosion across the geographical extent of the Australian continent. In the Australian context, however, global fallout is not the only source of these isotopes. As part of its weapons development program the United Kingdom carried out a series of atmospheric and surface nuclear weapons tests at Maralinga, South Australia in 1956 and 1957. The tests have made a significant contribution to the Pu isotopic abundances present in the region around Maralinga and out to distances ∼1000 km, and impact on the assessment techniques used in the soil and sediment tracer studies. Quantification of the relative fallout contribution derived from detonations at Maralinga is complicated owing to significant contamination around the test site from numerous nuclear weapons safety trials that were also carried out around the site. We show that 236 U can provide new information on the component of the fallout that is derived from the local nuclear weapons tests, and highlight the potential of 236 U as a new fallout tracer. - Highlights: • Measured 236 U inventories around the Maralinga Test Nuclear weapons test site. • Comparison of 236 U and 239 Pu soil depth profiles at Maralinga. • Differences in 236 U and 239 Pu inventories indicate most Pu fallout is from the safety trials, rather than the weapons tests.

  3. Position paper: Live load design criteria for Project W-236A Multi-Function Waste Tank Facility

    International Nuclear Information System (INIS)

    Giller, R.A.

    1995-01-01

    The purpose of this paper is to discuss the live loads applied to the underground storage tanks of the Multi Function Waste Tank Facility, and to provide the basis for Project W-236A live load criteria. Project 236A provides encompasses building a Weather Enclosure over the two underground storage tanks at the 200-West area. According to the Material Handling Study, the Groves AT 1100 crane used within the Weather Enclosure will have a gross vehicle weight of 66.5 tons. Therefore, a 100-ton concentrated live load is being used for the planning of the construction of the Weather Enclosure

  4. Fast radiochemical procedure to measure neptunium, plutonium, americium and curium in environmental samples for application in environmental monitoring and in radioecology research

    International Nuclear Information System (INIS)

    Pimpel, M.; Schuettelkopf, H.

    1984-01-01

    A radiochemical method is described by which Np, Pu, Am and Cm in environmental samples can be determined. The transuranium elements are dissolved with acids out of the ashed material. Np/Pu is separated from Am/Cm by sequential extraction using TOPO/cyclohexane. The two fractions are radiochemically purified. Np-237, Pu-239+240, Pu-238 and Pu-236 as well as Am-243, Am-241, Cm-244 and Cm-242 are measured by alpha spectrometery. Pu-236, Am-243 and Np-239 are used to determine the respective yields. A fast method of Np-239 preparation is described. The chemical yields range from 60 to 90%. The detection limit attained per nuclide is 10 fCi/sample. 20 reference, 1 table

  5. Production and Evaluation of 236gNp and Reference Materials for Naturally Occurring Radioactive Materials

    Science.gov (United States)

    Larijani, Cyrus Kouroush

    This thesis is based on the development of a radiochemical separation scheme capable of separating both 236gNp and 236Pu from a uranium target of natural isotopic composition ( 1 g uranium) and 200 MBq of fission decay products. The isobaric distribution of fission residues produced following the bombardment of a natural uranium target with a beam of 25 MeV protons has been evaluated. Decay analysis of thirteen isobarically distinct fission residues were carried out using high-resolution gamma-ray spectrometry at the UK National Physical Laboratory. Stoichiometric abundances were calculated via the determination of absolute activity concentrations associated with the longest-lived members of each isobaric chain. This technique was validated by computational modelling of likely sequential decay processes through an isobaric decay chain. The results were largely in agreement with previously published values for neutron bombardments on natural uranium at energies of 14 MeV. Higher relative yields of products with mass numbers A 110-130 were found, consistent with the increasing yield of these radionuclides as the bombarding energy is increased. Using literature values for the production cross-section for fusion of protons with uranium targets, it is estimated that an upper limit of approximately 250 Bq of activity from the 236Np ground state was produced in this experiment. Using a radiochemical separation scheme, Np and Pu fractions were separated from the produced fission decay products, with analyses of the target-based final reaction products made using Inductively Couple Plasma Mass Spectrometry (ICP-MS) and high-resolution alpha and gamma-ray spectrometry. In a separate research theme, reliable measurement of Naturally Occurring Radioactive Materials is of significance in order to comply with environmental regulations and for radiological protection purposes. The thesis describes the standardisation of three reference materials, namely Sand, Tuff and TiO2 which

  6. 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

    2016-03-07

    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.

  7. Design review plan for Multi-Function Waste Tank Facility (Project W-236A)

    International Nuclear Information System (INIS)

    Renfro, G.G.

    1994-01-01

    This plan describes how the Multi-Function Waste Tank Facility (MWTF) Project conducts reviews of design media; describes actions required by Project participants; and provides the methodology to ensure that the design is complete, meets the technical baseline of the Project, is operable and maintainable, and is constructable. Project W-236A is an integrated project wherein the relationship between the operating contractor and architect-engineer is somewhat different than that of a conventional project. Working together, Westinghouse Hanford Company (WHC) and ICF Karser Hanford (ICF KH) have developed a relationship whereby ICF KH performs extensive design reviews and design verification. WHC actively participates in over-the-shoulder reviews during design development, performs a final review of the completed design, and conducts a formal design review of the Safety Class I, ASME boiler and Pressure Vessel Code items in accordance with WHC-CM-6-1, Standard Engineering Practices

  8. Method for 236U Determination in Seawater Using Flow Injection Extraction Chromatography and Accelerator Mass Spectrometry

    DEFF Research Database (Denmark)

    Qiao, Jixin; Hou, Xiaolin; Steier, Peter

    2015-01-01

    An automated analytical method implemented in a flow injection (FI) system was developed for rapid determination of 236U in 10 L seawater samples. 238U was used as a chemical yield tracer for the whole procedure, in which extraction chromatography (UTEVA) was exploited to purify uranium, after...... experimental parameters affecting the analytical effectiveness were investigated and optimized in order to achieve high chemical yields and simple and rapid analysis as well as low procedure background. Besides, the operational conditions for the target preparation prior to the AMS measurement were optimized......, on the basis of studying the coprecipitation behavior of uranium with iron hydroxide. The analytical results indicate that the developed method is simple and robust, providing satisfactory chemical yields (80−100%) and high analysis speed (4 h/sample), which could be an appealing alternative to conventional...

  9. Lifetime of the long-lived isomer of /sup 236/Np from. cap alpha. -,. beta. - and electron-capture decay measurements

    Energy Technology Data Exchange (ETDEWEB)

    Lindner, M.; Dupzyk, R.J.; Hoff, R.W.; Nagle, R.J. (California Univ., Livermore (USA). Lawrence Livermore National Lab.)

    1981-01-01

    The half-life of long-lived /sup 236/Np, due to ..cap alpha.., ..beta.. and electron-capture decay, was found to be 1.55 x 10/sup 5/ yr. Of all decays, 88% populate excited states in /sup 236/U and 12% populate levels in /sup 236/Pu. Lifetimes measured by growth of the ground states of /sup 236/U and /sup 236/Pu agree with values from corresponding ..gamma.. de-excitations in these daughter nuclei. Therefore, nearly all the electron-capture decays populate the 6/sup +/ level of the ground-state band in /sup 236/U. Similarly, essentially all the ..beta../sup -/ decay populates an analogous 6/sup +/ level in /sup 236/Pu, which de-excites through a previously unreported transition of 158.3 keV. If a very week ..gamma..-ray at 894 keV can be ascribed to a level in /sup 232/U populated by ..beta.. decay of /sup 232/Pa, its existence establishes a 0.2% ..cap alpha..-branching decay in /sup 236/Np.

  10. The regulatory effect of SC-236 (4-[5-(4-chlorophenyl)-3-(trifluoromethyl)-1-pyrazol-1-l] benzenesulfonamide) on stem cell factor induced migration of mast cells

    International Nuclear Information System (INIS)

    Kim, Su-Jin; Jeong, Hyun-Ja; Park, Rae-Kil; Lee, Kang-Min; Kim, Hyung-Min; Um, Jae-Young; Hong, Seung-Heon

    2007-01-01

    SC-236 (4-[5-(4-chlorophenyl)-3-(trifluoromethyl)-1-pyrazol-1-]benzenesulfonamide; C 16 H 11 ClF 3 N 3 O 2 S), is a highly selective cyclooxygenase (COX)-2 inhibitor. Recently, there have been reports that SC-236 protects against cartilage damage in addition to reducing inflammation and pain in osteoarthritis. However, the mechanism involved in the inflammatory allergic reaction has not been examined. Mast cells accumulation can be related to inflammatory conditions, including allergic rhinitis, asthma, and rheumatoid arthritis. The aim of the present study is to investigate the effects of SC-236 on stem cell factor (SCF)-induced migration, morphological alteration, and cytokine production of rat peritoneal mast cells (RPMCs). We observed that SCF significantly induced the migration and morphological alteration. The ability of SCF to enhance migration and morphological alteration was abolished by treatment with SC-236. In addition, production of tumor necrosis factor (TNF)-α, interleukin (IL)-1β, and vascular endothelial growth factor (VEGF) production induced by SCF was significantly inhibited by treatment with SC-236. Previous work has demonstrated that SCF-induced migration and cytokine production of mast cells require p38 MAPK activation. We also showed that SC-236 suppresses the SCF-induced p38 MAPK activation in RPMCs. These data suggest that SC-236 inhibits migration and cytokine production through suppression of p38 MAPK activation. These results provided new insight into the pharmacological actions of SC-236 and its potential therapeutic role in the treatment of inflammatory allergic diseases

  11. Determination of {sup 236}U in environmental samples by single extraction chromatography coupled to triple-quadrupole inductively coupled plasma-mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Guosheng [Department of Radiation Chemistry, Institute of Radiation Emergency Medicine, Hirosaki University, 66-1 Hon-cho, Hirosaki, Aomori, 036-8564 (Japan); Division of Nuclear Technology and Applications, Institute of High Energy Physics, Chinese Academy of Sciences (China); Beijing Engineering Research Center of Radiographic Techniques and Equipment, Beijing, 100049 (China); Tazoe, Hirofumi [Department of Radiation Chemistry, Institute of Radiation Emergency Medicine, Hirosaki University, 66-1 Hon-cho, Hirosaki, Aomori, 036-8564 (Japan); Yamada, Masatoshi, E-mail: myamada@hirosaki-u.ac.jp [Department of Radiation Chemistry, Institute of Radiation Emergency Medicine, Hirosaki University, 66-1 Hon-cho, Hirosaki, Aomori, 036-8564 (Japan)

    2016-11-09

    In order to measure trace {sup 236}U and {sup 236}U/{sup 238}U in environmental samples with a high matrix effect, a novel and simple method was developed that makes the digestion and purification procedures compatible with advanced triple-quadrupole inductively coupled plasma-mass spectrometry. A total dissolution of sample with HF + HNO{sub 3} + HClO{sub 4} was followed by chromatographic separation with a single resin column containing normal type DGA resin (N,N,N′,N’-tetra-n-octyldiglycolamide) as the extractant system. The analytical accuracy and precision of {sup 236}U/{sup 238}U ratios, measured as {sup 236}U{sup 16}O{sup +}/{sup 238}U{sup 16}O{sup +}, were examined by using the reference materials IAEA-135, IAEA-385, IAEA-447, and JSAC 0471. The low method detection limit (3.50 × 10{sup −6} Bq kg{sup −1}) makes it possible to perform routine monitoring of environmental {sup 236}U due to global fallout combined with the Fukushima Daiichi Nuclear Power Plant accident fallout (>10{sup −5} Bq kg{sup −1}). Finally, the developed method was successfully applied to measure {sup 236}U/{sup 238}U ratios and {sup 236}U activities in soil samples contaminated by the accident. The low {sup 236}U/{sup 238}U atom ratios ((1.50–13.5) × 10{sup −8}) and {sup 236}U activities ((2.25–14.1) × 10{sup −2} mBq kg{sup −1}) indicate {sup 236}U contamination was mainly derived from global fallout in the examined samples. - Highlights: • A simple {sup 236}U/{sup 238}U analytical method has been developed. • The separation required just one DGA column chromatography. • {sup 236}U/{sup 238}U atom ratios in soil were measured by ICP-MS/MS. • {sup 236}U/{sup 238}U atom ratios of (1.50–13.5) × 10{sup −8} were observed in Japanese samples. • {sup 236}U activities of (2.25–14.1) × 10{sup −2} mBq kg{sup −1} were found in Japanese samples.

  12. 33 CFR 110.236 - Pacific Ocean off Barbers Point, Island of Oahu, Hawaii: Offshore pipeline terminal anchorages.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Pacific Ocean off Barbers Point... Grounds § 110.236 Pacific Ocean off Barbers Point, Island of Oahu, Hawaii: Offshore pipeline terminal... regulations. (1) No vessels may anchor, moor, or navigate in anchorages A, B, C, or D except: (i) Vessels...

  13. 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.

    Science.gov (United States)

    León Vintró, L; Mitchell, P I; Omarova, A; Burkitbayev, M; Jiménez Nápoles, H; Priest, N D

    2009-04-01

    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 (241)Am, (239,240)Pu and (238)U concentrations in well waters within the study area are in the range 0.04-87mBq dm(-3), 0.7-99mBq dm(-3), and 74-213mBq dm(-3), respectively, and for (241)Am and (239,240)Pu 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 0.01mBq dm(-3), 0.08mBq dm(-3) and 0.32mBq dm(-3) for (241)Am, (239,240)Pu and (238)U, respectively. The (235)U/(238)U 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 11-42microSv (mean 21microSv). Presently, the ground water feeding these wells would not appear to be contaminated with

  14. 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

    Energy Technology Data Exchange (ETDEWEB)

    Leon Vintro, L. [School of Physics, University College Dublin, Belfield, Dublin 4 (Ireland)], E-mail: luis.leon@ucd.ie; Mitchell, P.I.; Omarova, A. [School of Physics, University College Dublin, Belfield, Dublin 4 (Ireland); Burkitbayev, M. [Department of Inorganic Chemistry, Al-Faraby Kazakh National University, Almaty (Kazakhstan); Jimenez Napoles, H. [School of Physics, University College Dublin, Belfield, Dublin 4 (Ireland); Priest, N.D. [School of Health and Social Sciences, Middlesex University, Enfield, EN3 4SA (United Kingdom)

    2009-04-15

    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 {sup 241}Am, {sup 239,240}Pu and {sup 238}U concentrations in well waters within the study area are in the range 0.04-87 mBq dm{sup -3}, 0.7-99 mBq dm{sup -3}, and 74-213 mBq dm{sup -3}, respectively, and for {sup 241}Am and {sup 239,240}Pu 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{sup -3}, 0.08 mBq dm{sup -3} and 0.32 mBq dm{sup -3} for {sup 241}Am, {sup 239,240}Pu and {sup 238}U, respectively. The {sup 235}U/{sup 238}U 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 {mu}Sv (mean 21 {mu

  15. Solvent extraction of uranium(VI), plutonium(VI) and americium(III) with HTTA/HPMBP using mono- and bi-functional neutral donors. Synergism and thermodynamics

    International Nuclear Information System (INIS)

    Pai, S.A.; Lohithakshan, K.V.; Mithapara, P.D.; Aggarwal, S.K.

    2000-01-01

    Synergistic extraction of hexavalent uranium and plutonium as well as trivalent americium was studied in HNO 3 with thenoyl, trifluoro-acetone (HTTA)/1-phenyl, 3-methyl, 4-benzoyl pyrazolone-5 (HPMBP) in combination with neutral donors viz. DPSO, TBP, TOPO (mono-functional) and DBDECMP, DHDECMP, CMPO (bi-functional) with wide basicity range using benzene as diluent. A linear correlation was observed when the equilibrium constant log Ks for the organic phase synergistic reaction of both U(VI) and Pu(VI) with either of the chelating agents HTTA or HPMBP was plotted vs. the basicity (log Kh) of the donor (both mono- and bi-functional) indicating bi-functional donors also behave as mono-functional. This was supported by the thermodynamic data (ΔG 0 , ΔH 0 , ΔS 0 ) obtained for these systems. The organic phase adduct formation reactions were identified for the above systems from the thermodynamic data. In the Am(III) HTTA system log K s values of bi-functional donors were found to be very high and deviate from the linear plot (log K s vs. log K h ) obtained for mono-functional donors, indicating that they function as bi-functional for the Am(III)/HTTA) system studied. This was supported by high +ve ΔS 0 values obtained for this system. (author)

  16. Diluent and extractant effects on the enthalpy of extraction of uranium(VI) and americium(III) nitrates by trialkyl phosphates

    International Nuclear Information System (INIS)

    Srinivasan, T.G.; Vasudeva Rao, P.R.; Sood, D.D.

    1998-01-01

    The effect of various diluents such as n-hexane, n-heptane n-octane, isooctane, n-decane, n-undecane, n-dodecane, n-tetradecane, n-hexadecane, cyclohexane, benzene, toluene, p-xylene, mesitylene and o-dichlorobenzene on the enthalpy of extraction of uranyl nitrate by tri-n-amyl phosphate (TAP) over the temperature range 283 K--333 K has been studied. The results indicate that the enthalpy of extraction does not vary significantly with the diluents studied. Also enthalpies of extraction of uranyl nitrate and americium(III) nitrate by neutral organo phosphorous extractants such as tri-n-butyl phosphate (TBP), tri-n-amyl phosphate (TAP), tri-sec-butyl phosphate (TsBP), tri-isoamyl phosphate (TiAP) and tri-n-hexyl phosphate (THP) have been studied. An attempt has been made to explain the trends, on the basis of the nature of the solvate formed and the different terms which contribute to the overall enthalpy change

  17. The design of a multisource americium-beryllium (Am-Be) neutron irradiation facility using MCNP for the neutronic performance calculation.

    Science.gov (United States)

    Sogbadji, R B M; Abrefah, R G; Nyarko, B J B; Akaho, E H K; Odoi, H C; Attakorah-Birinkorang, S

    2014-08-01

    The americium-beryllium neutron irradiation facility at the National Nuclear Research Institute (NNRI), Ghana, was re-designed with four 20 Ci sources using Monte Carlo N-Particle (MCNP) code to investigate the maximum amount of flux that is produced by the combined sources. The results were compared with a single source Am-Be irradiation facility. The main objective was to enable us to harness the maximum amount of flux for the optimization of neutron activation analysis and to enable smaller sample sized samples to be irradiated. Using MCNP for the design construction and neutronic performance calculation, it was realized that the single-source Am-Be design produced a thermal neutron flux of (1.8±0.0007)×10(6) n/cm(2)s and the four-source Am-Be design produced a thermal neutron flux of (5.4±0.0007)×10(6) n/cm(2)s which is a factor of 3.5 fold increase compared to the single-source Am-Be design. The criticality effective, k(eff), of the single-source and the four-source Am-Be designs were found to be 0.00115±0.0008 and 0.00143±0.0008, respectively. Copyright © 2014 Elsevier Ltd. All rights reserved.

  18. 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)

    Beims, H.D.

    1986-01-01

    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) [de

  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. Study and modeling of lanthanide(3)-L and americium(3)-L (With L = NTA, EDTA and DTPA) in high ionic strength aqueous solutions

    International Nuclear Information System (INIS)

    Rocchiccioli, F.

    2000-01-01

    The dissociation constants of NTA, EDTA, DTPA in NaCl, NaClO 4 , LiCl and LiClO 4 aqueous solutions of various ionic strengths have been gathered from the literature and from the Critical Surveys of Stability Constants. These values have been completed by a series of pKa values obtained in the same salted solution at higher ionic strengths by potentiometry involving a combined glass electrode at 25 deg C. The dependencies of the pKas versus the ionic strength have been investigated by using the Specific Interaction Theory (SIT), the parabolic model and the Pitzer model. The stability constants of complexes involving lanthanides (III), such as Nd 3+ , Eu 3+ and Lu 3+ , and americium (III), with the ligands previously mentioned in NaCl, NaClO 4 , LiCl and LiClO 4 aqueous solutions of high ionic strengths have been determined. The methods used for the determination of the stability constants for the lanthanide complexes are various: direct measurements by potentiometry when possible, UV-visible absorption spectroscopy involving Arsenazo (III) as a competitor ligand. For the actinide complexes, solvent extraction experiments have been performed. The different systems, along with the dissociation constants of several complexes in the same aqueous media, have been successfully modeled by the SIT, the parabolic method and the Pitzer method. (author)

  1. Epidemiological and clinical features of primary liver cancer: an analysis of 236 patients

    Directory of Open Access Journals (Sweden)

    ZHAO Rongrong

    2016-08-01

    Full Text Available ObjectiveTo investigate the epidemiological and clinical features of patients with primary liver cancer (PLC. MethodsA retrospective analysis was performed for the clinical data of 236 patients with complete information who were admitted to The First Hospital of Lanzhou University and diagnosed with PLC for the first time form August 2012 to August 2014, and their epidemiological and clinical features were analyzed. The chi-square test was used for comparison of categorical data between groups. ResultsAmong the 236 PLC patients, there were 198 male patients (83.9% and 38 female patients (16.1%, and the patients aged 41-60 years has the highest incidence rate (58.5%, 138/236. Nineteen patients had a family history of liver cancer, 28 had a history of heavy drinking, 34 were complicated by type 2 diabetes, and 44 were complicated by hypertension. Among these patients, 232 (98.3% developed PLC on the basis of chronic liver disease, and 4 (1.7% had no chronic liver disease. There were 207 patients (87.7% with chronic HBV infection, and most of them had HBeAg-negative infection. Fourteen patients (5.9% had chronic HCV infection, 5 (2.1% had HBV/HCV co-infection, and 6 (2.5% had chronic alcoholic hepatitis. Among the 212 patients with HBV infection, 51(241% had HBeAg-positive chronic hepatitis B, and 95(448% had HBeAg-negative chronic hepatitis B; there was significant difference in HBV DNA level between the two groups (χ2=40687,Ρ=0001. Among all the PLC patients, 104 had an alpha-fetoprotein(AFP level of >400 IU/ml, 48 had an AFP level of 200-400 IU/ml, and 84 had an AFP level of <200 IU/ml; 154 (62.3% had a single lesion, and 72 (30.5% had multiple lesions; most (72.7% of patients with a single lesion had the single lesion in the right lobe, and the proportions of patients with multiple lesions in the right lobe and in both lobes accounted for 58.3% and 41.7%, respectively. Among the 80 PLC patients with

  2. The distribution of {sup 236}U/{sup 238}U in the North Atlantic and adjacent oceans; Die Verteilung von {sup 236}U/{sup 238}U im Nordatlantik und den angrenzenden Ozeanen

    Energy Technology Data Exchange (ETDEWEB)

    Christl, Marcus; Casacuberta, Nuria; Lachner, Johannes; Maxeiner, Sascha; Vockenhuber, Christof; Synal, Hans-Arno [Labor fuer Ionenstrahlphysik, ETH Zuerich (Switzerland); Herrmann, Juergen [Bundesamt fuer Seeschifffahrt und Hydroghraphie, Hamburg (Germany); Castrillejo, Maxi; Masque, Pere [Universitat Autonoma de Barcelona (Spain); Rutgers van der Loeff, Michiel [Alfred-Wegener-Institut, Bremerhaven (Germany)

    2015-07-01

    The technical developments of recent years, such as the introduction of helium as a stripping gas, make compact AMS systems probably among the most sensitive analyzers available for ultra-trace analyzes of actinides in the environment. Such systems are particularly suitable for the trace analysis of {sup 236}U since conventional mass spectrometry does not provide the necessary suppression of the substrate caused by molecules or neighboring masses. Over the past few years, unique data sets of {sup 236}U/{sup 238}U have been produced at the AMS System Tandy of the ETH Zurich in the Atlantic and Arctic Ocean as well as in the Mediterranean and the North Sea. This lecture will provide a brief overview of the latest technical developments in the field of heavy ion analysis at compact AMS plants at ETH Zurich. In the second part, the produced data sets are then assembled and the current understanding of this new ocean tracer discussed. [German] Die technischen Entwicklungen der letzten Jahre, wie zum Beispiel die Einfuehrung von Helium als stripper Gas, machen kompakte AMS Systeme wahrscheinlich zu den sensitivsten verfuegbaren Analysegeraeten fuer Ultra-Spurenstoffanalysen von Aktiniden in der Umwelt. Solche Systeme eignen sich im Besonderen zur Spurenanalyse von {sup 236}U, da konventionelle Massenspektrometrie hier nicht die erforderliche Unterdrueckung des durch Molekuele oder Nachbarmassen verursachten Untergrundes bietet. Am AMS System Tandy der ETH Zuerich wurden waehrend der letzten Jahre einzigartige Datensaetze von {sup 236}U/{sup 238}U im Atlantischen und Arktischen Ozean, sowie im Mittelmeer und der Nordsee produziert. In diesem Vortrag soll zunaechst ein kurzer Ueberblick ueber die neuesten technischen Entwicklungen im Bezug auf Schwerionen Analysen an kompakten AMS Anlagen der ETH Zuerich gegeben werden. Im zweiten Teil werden dann die produzierten Datensaetze zusammengefuegt und das gegenwaertige Verstaendnis dieses neuen Ozean-Tracers diskutiert.

  3. Use of 236Pu and 242Pu as a radiochemical tracer for estimation of Pu in bioassay samples by fission track analysis

    International Nuclear Information System (INIS)

    Sawant, Pramilla D.; Prabhu, Supreetha P.; Kalsi, P.C.

    2008-01-01

    236 Pu and 242 Pu are routinely used as radiochemical yield monitors in India for bioassay monitoring of occupational workers by alpha spectrometry. Fission Track Analysis (FTA) is also being standardized for trace level determination of Pu in bioassay samples. The present study, reports the utility of 236 Pu and 242 Pu as radiochemical tracers in estimation of Pu in bioassay samples by FTA technique. The advantages of using 236 Pu tracer in FTA over 242 Pu as well as the interference caused due to presence of 241 Pu in the bioassay samples of occupational workers handling power reactor grade Pu is discussed. (author)

  4. Tank 241-TX-118, core 236 analytical results for the final report

    International Nuclear Information System (INIS)

    ESCH, R.A.

    1998-01-01

    This document is the analytical laboratory report for tank 241-TX-118 push mode core segments collected between April 1, 1998 and April 13, 1998. The segments were subsampled and analyzed in accordance with the Tank 241-TX-118 Push Mode Core sampling and Analysis Plan (TSAP) (Benar, 1997), the Safety Screening Data Quality Objective (DQO) (Dukelow, et al., 1995), the Data Quality Objective to Support Resolution of the Organic Complexant Safety Issue (Organic DQO) (Turner, et al, 1995) and the Historical Model Evaluation Data Requirements (Historical DQO) (Sipson, et al., 1995). The analytical results are included in the data summary table (Table 1). None of the samples submitted for Differential Scanning Calorimetry (DSC) and Total Organic Carbon (TOC) exceeded notification limits as stated in the TSAP (Benar, 1997). One sample exceeded the Total Alpha Activity (AT) analysis notification limit of 38.4microCi/g (based on a bulk density of 1.6), core 236 segment 1 lower half solids (S98T001524). Appropriate notifications were made. Plutonium 239/240 analysis was requested as a secondary analysis. The statistical results of the 95% confidence interval on the mean calculations are provided by the Tank Waste Remediation Systems Technical Basis Group in accordance with the Memorandum of Understanding (Schreiber, 1997) and are not considered in this report

  5. Effect translational invariance in low-lying electric dipole excitations in 236U and 238U

    International Nuclear Information System (INIS)

    Ertugral, F.

    2005-01-01

    In this paper the translational invariant QRPA approach suggested by Pyatov [1] for the spherical nuclei has been extended to describe the 1 - states in deformed nuclei. The role of spurious centre-of-motion state on the Pygmy dipole resonance (PDR) has been investigated in the deformed 236 U and 238 U nuclei. It has been shown that the effect of taking into account the translational invariance of the Hamiltonians in the QRPA with separation of zero energy spurious solutions are noticeable in both the low energy density of 1 - states and in the PDR. Present investigation demonstrates the advantage of the translational invariant QRPA over the non translational invariant one. Within the translational invariant model the effect of removing spurious states on the E1 strength distribution is stronger than in none invariant QRPA (∼20%) for the states up to the neutron binding energy. It is found that the spurious state is spread over many levels, the largest admixture being situated in the region of the energy spacing between nuclear shells o w h . The giant resonance states contain, as a rule, very small admixtures of the spurious state

  6. Functions and requirements for Project W-236B, Initial Pretreatment Module: Revision 1

    International Nuclear Information System (INIS)

    Swanson, L.M.

    1994-01-01

    Hanford Site tank waste supernatants will be pretreated to separate the low-level and high-level fractions. The low-level waste fraction, containing the bulk of the chemical constituents, must be processed into a vitrified waste product which will be disposed of onsite, in a safe, environmentally sound, and cost effective manner. The high-level waste fraction separated during supernatant pretreatment (primarily cesium) will be recombined with an additional high-level waste fraction generated from pretreatment of the tank waste sludges and solids. This combined high-level waste fraction will be immobilized as glass and disposed in a geological repository. The purpose of this document is to establish the functional requirements baseline for Project W-236B, Initial Pretreatment Module, by defining the level 5 and 6 functions and requirements for the project. A functional analysis approach has been used to break down the program functions and associated physical requirements that each function must meet. As the systems engineering process evolves, the design requirements document will replace this preliminary functions and requirements document. The design requirements document (DRD) will identify key decisions and associated uncertainties that impact the project. A revision of this document to a DRD is not expected to change the performance requirements or open issues. However, additional requirements and issues may be identified

  7. Feasibility studies to assess the use of 236Pu as a radiochemical yield monitor in bioassay samples

    International Nuclear Information System (INIS)

    Sawant, P.D.; Kalsi, P.C.

    2007-01-01

    Various plutonium compounds are handled in nuclear facilities of BARC. Hence, there is a possibility of occupational workers getting exposed to Pu. In vitro bioassay monitoring in which Pu is separated by chemical procedures from excreta samples and estimated by alpha-spectrometry, is the method of choice for the evaluation of internal dose to the occupational workers handling Pu. However, this method requires a suitable Pu tracer for reducing the uncertainties due to chemical yield in the separation, electro-deposition and counting efficiency. 242 Pu is commonly used as a tracer but due to its non-availability, efforts were made earlier to indigenously synthesis 236 Pu by proton irradiation of 237 Np in BARC-TIFR pelletron facility. The present study, reports the feasibility of using 236 Pu as a radiochemical yield monitor (tracer) in bioassay samples. (author)

  8. Fission Fragment Angular Distributions in the $^{234}$U(n,f) and $^{236}$U(n,f) reactions

    CERN Multimedia

    We propose to measure the fission fragment angular distribution (FFAD) of the $^{234}$U(n,f) and $^{236}$U (n,f) reactions with the PPAC detection setup used in previous n_TOF-14 experiment. This experiment would take advantage of the high resolution of the n_TOF facility to investigate the FFAD behaviour in the pronounced vibrational resonances that have been observed between 0.1 and 2 MeV for the thorium cycle isotopes. In addition, the angular distribution of these isotopes will be measured for the first time beyond 14 MeV. Furthermore, the experiment will also provide the fission cross section with reduced statistical uncertainty, extending the $^{236}$U(n,f) data up to 1 GeV

  9. (236)U and (239,)(240)Pu ratios from soils around an Australian nuclear weapons test site.

    Science.gov (United States)

    Tims, S G; Froehlich, M B; Fifield, L K; Wallner, A; De Cesare, M

    2016-01-01

    The isotopes (236)U, (239)Pu and (240)Pu are present in surface soils as a result of global fallout from nuclear weapons tests carried out in the 1950's and 1960's. These isotopes potentially constitute artificial tracers of recent soil erosion and sediment movement. Only Accelerator Mass Spectrometry has the requisite sensitivity to measure all three isotopes at these environmental levels. Coupled with its relatively high throughput capabilities, this makes it feasible to conduct studies of erosion across the geographical extent of the Australian continent. In the Australian context, however, global fallout is not the only source of these isotopes. As part of its weapons development program the United Kingdom carried out a series of atmospheric and surface nuclear weapons tests at Maralinga, South Australia in 1956 and 1957. The tests have made a significant contribution to the Pu isotopic abundances present in the region around Maralinga and out to distances ∼1000 km, and impact on the assessment techniques used in the soil and sediment tracer studies. Quantification of the relative fallout contribution derived from detonations at Maralinga is complicated owing to significant contamination around the test site from numerous nuclear weapons safety trials that were also carried out around the site. We show that (236)U can provide new information on the component of the fallout that is derived from the local nuclear weapons tests, and highlight the potential of (236)U as a new fallout tracer. Crown Copyright © 2015. Published by Elsevier Ltd. All rights reserved.

  10. Solubility of plutonium and americium-241 from rumen contents of cattle grazing on plutonium-contaminated desert vegetation in in vitro bovine gastrointestinal fluids - August 1975 to January 1977

    International Nuclear Information System (INIS)

    Barth, J.; Giles, K.R.; Brown, K.W.

    1985-01-01

    The alimentary solubility of plutonium and americium-241 ingested by cattle grazing at Area 13 of the Nevada Test Site and the Clean Slate II site on the Tonopah Test Range in Nevada was studied in a series of experiments. For each experiment, or trial, rumen contents collected from a fistulated steer or a normal animals at the time of sacrifice were incubated in simulated bovine gastrointestinal fluids, and the solubility of plutonium and americium was analyzed following the abomasal, duodenal, jejunal, and lower intestinal digestive states. For Area 13, the peak plutonium-238 solubilities ranged from 1.09 to 9.60 percent for animals grazing in the inner enclosure that surrounds ground zero (GZ); for animals grazing in the outer enclosure, the peaks ranged from 1.86 to 18.46%. The peak plutonium-239 solubilities ranged from 0.71 to 4.81% for animals from the inner enclosure and from 0.71 to 3.61% for animals from the outer enclosure. Plutonium-238 was generally more soluble than plutonium-239. Plutonium ingested by cattle grazing in the outer enclosure was usually more soluble than plutonium ingested by cattle grazing in the inner enclosure. The highest concentrations of plutonium in the rumen contents of cattle grazing in the inner enclosure were found in trials conducted during August and November 1975 and January 1976. These concentrations decreased during the February, May, and July 1976 trials. The decrease was followed by an increase in plutonium concentration during the November 1976 trial. The concentration of americium-241 followed the same trend. 13 references, 13 tables

  11. Structural study of U1-xAmxO2±δ oxide microspheres dedicated to the production of americium bearing blankets

    International Nuclear Information System (INIS)

    Caisso, Marie

    2016-01-01

    One of the studied routes to reduce nuclear waste amount, is, after plutonium recycling, americium (Am) heterogeneous transmutation in fast neutron reactors, through the generation of short-lives and inert elements. Am irradiation requires the fabrication of U 1-x Am x O 2±δ pellets and the CRMP (Calcined Resin Microsphere Pelletization) process is currently considered as one the most promising candidate among other fabrication routes. It is based, before pellet sintering, on the compaction of U 1-x Am x O 2±δ oxide microspheres, synthesized through the thermal conversion of ion exchange resin microspheres, loaded with UO 2 2+ and Am 3+ cations. Compared to standard methods using powder metallurgy, CRMP process favours pressing step (easy microsphere flow) while limiting generation of highly radioactive Am-based fine particles. In this context, this PhD work was focused on the exhaustive characterization of CRMP process different steps, from a mechanistic and structural point of view. The cation molecular complex used in the resin was thus determined, highlighting carboxylic bidentate ligand binding around U and Am elements. Thermal conversion was also in-situ followed, and the structures of the different synthesized compounds evidenced and accurately characterized, i.e. (U 1-x Am x ) 3 O 8 et U 1-x Am x O 2±δ . Am substitution in each of them was explained, revealing related distortions around U and Am cations. Finally, sintering of U 1-x Am x O 2±δ microspheres shaped into pellets was studied, showing a two-step densification. This unusual behavior corresponds to multi-scale reorganization into the material during sintering thermal treatment, associated to the presence of nanoparticles in the green pellet that sinter at low temperature. (author) [fr

  12. 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.)

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

    International Nuclear Information System (INIS)

    Ketelaer, Jens

    2010-01-01

    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 ∝ 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 241 Am could be measured directly for the first time. (orig.)

  14. Project W-236A, work plan for preparation of a design requirements document

    International Nuclear Information System (INIS)

    Groth, B.D.

    1995-01-01

    This work plan outlines the tasks necessary, and defines the organizational responsibilities for preparing a Design Requirements Document (DRD) for project W-236A, Multi-Function Waste Tank Facility (MWTF). A DRD is a Systems Engineering document which bounds, at a high level, the requirements of a discrete system element of the Tank Waste Remediation System (TWRS) Program. This system element is usually assigned to a specific project, in this case the MWTF. The DRD is the document that connects the TWRS program requirements with the highest level projects requirements and provides the project's link to the overall TWRS mission. The MWTF DRD effort is somewhat unique in that the project is already in detailed design, whereas a DRO is normally prepared prior to preliminary design. The MWTF design effort was initiated with a Functional Design Criteria (FDC) and a Supplemental Design Requirements Document (SDRD) bounding the high level requirements. Another unique aspect of this effort is that some of the TWRS program requirements are still in development. Because of these unique aspects of the MWTF DRD development, the MWTF will be developed from existing TWRS Program requirements and project specific requirements contained in the FDC and SDRD. The following list describes the objectives of the MWTF DRD: determine the primary functions of the tanks through a functional decomposition of the TWRS Program high level functions; allocate the primary functions to a sub-system architecture for the tanks; define the fundamental design features in terms of performance requirements for the system and subsystems; identify system interfaces and design constraints; and document the results in a DRD

  15. Neutron-Induced Fission Cross Section of Uranium, Americium and Curium Isotopes. Progress report - Research Contract 14485, Coordinated Research Project on Minor Actinide Neutron Reaction Data (MANREAD)

    International Nuclear Information System (INIS)

    Alekseev, A.A.; Bergman, A.A.; Berlev, A.I.; Koptelov, E.A.; Samylin, B.F.; Trufanov, A.M.; Fursov, B.I.; Shorin, V.S.

    2009-12-01

    This report contains brief description of the Lead Slowing Down Spectrometer and results of measurements of neutron-induced fission cross sections for 236 U, 242m Am, 243 Cm, 244 Cm, 245 Cm and 246 Cm done at this spectrometer. The work was partially supported through the IAEA research contract RC-14485-RD in the framework of the IAEA Coordinated Research Project 'Minor Actinide Neutron Reaction Data (MANREAD)'. The detailed description of the experimental set up, measurements procedure and data treatment can be found in the JIA-1182 (2007) and JIA-1212 (2009) reports from the Institute of Nuclear Research of the Russian Academy of Science published in Russian. Part 1 contains the first year report of the research contract and part 2 the second year report. (author)

  16. EPISODIC STAR FORMATION COUPLED TO REIGNITION OF RADIO ACTIVITY IN 3C 236

    International Nuclear Information System (INIS)

    Tremblay, Grant R.; O'Dea, Christopher P.; Baum, Stefi A.; Koekemoer, Anton M.; Sparks, William B.; De Bruyn, Ger; Schoenmakers, Arno P.

    2010-01-01

    We present Hubble Space Telescope Advanced Camera for Surveys and STIS FUV/NUV/optical imaging of the radio galaxy 3C 236, whose relic ∼4 Mpc radio jet lobes and inner 2 kpc compact steep spectrum (CSS) radio source are evidence of multiple epochs of active galactic nucleus (AGN) activity. Consistent with previous results, our data confirm the presence of four bright knots of FUV emission in an arc along the edge of the inner circumnuclear dust disk in the galaxy's nucleus, as well as FUV emission cospatial with the nucleus itself. We interpret these to be sites of recent or ongoing star formation. We present photometry of these knots, as well as an estimate for the internal extinction in the source using line ratios from archival ground-based spectroscopy. We estimate the ages of the knots by comparing our extinction-corrected photometry with stellar population synthesis models. We find the four knots cospatial with the dusty disk to be young, of order ∼10 7 yr old. The FUV emission in the nucleus, to which we do not expect scattered light from the AGN to contribute significantly, is likely due to an episode of star formation triggered ∼10 9 yr ago. We argue that the young ∼10 7 yr old knots stem from an episode of star formation that was roughly coeval with the event resulting in reignition of radio activity, creating the CSS source. The ∼10 9 yr old stars in the nucleus may be associated with the previous epoch of radio activity that generated the 4 Mpc relic source, before being cut off by exhaustion or interruption. The ages of the knots, considered in the context of both the disturbed morphology of the nuclear dust and the double-double morphology of the 'old' and 'young' radio sources, present evidence for an AGN/starburst connection that is possibly episodic in nature. We suggest that the AGN fuel supply was interrupted for ∼10 7 yr due to a minor merger event and has now been restored. The resultant nonsteady flow of gas in the disk is likely

  17. Determination of extremely low 236U/238U isotope ratios in environmental samples by sector-field inductively coupled plasma mass spectrometry using high-efficiency sample introduction

    International Nuclear Information System (INIS)

    Boulyga, Sergei F.; Heumann, Klaus G.

    2006-01-01

    A method by inductively coupled plasma mass spectrometry (Icp-Ms) was developed which allows the measurement of 236 U at concentration ranges down to 3 x 10 -14 g g -1 and extremely low 236 U/ 238 U isotope ratios in soil samples of 10 -7 . By using the high-efficiency solution introduction system APEX in connection with a sector-field ICP-MS a sensitivity of more than 5000 counts fg -1 uranium was achieved. The use of an aerosol desolvating unit reduced the formation rate of uranium hydride ions UH + /U + down to a level of 10 -6 . An abundance sensitivity of 3 x 10 -7 was observed for 236 U/ 238 U isotope ratio measurements at mass resolution 4000. The detection limit for 236 U and the lowest detectable 236 U/ 238 U isotope ratio were improved by more than two orders of magnitude compared with corresponding values by alpha spectrometry. Determination of uranium in soil samples collected in the vicinity of Chernobyl nuclear power plant (NPP) resulted in that the 236 U/ 238 U isotope ratio is a much more sensitive and accurate marker for environmental contamination by spent uranium in comparison to the 235 U/ 238 U isotope ratio. The ICP-MS technique allowed for the first time detection of irradiated uranium in soil samples even at distances more than 200 km to the north of Chernobyl NPP (Mogilev region). The concentration of 236 U in the upper 0-10 cm soil layers varied from 2 x 10 -9 g g -1 within radioactive spots close to the Chernobyl NPP to 3 x 10 -13 g g -1 on a sampling site located by >200 km from Chernobyl

  18. Determination of extremely low (236)U/(238)U isotope ratios in environmental samples by sector-field inductively coupled plasma mass spectrometry using high-efficiency sample introduction.

    Science.gov (United States)

    Boulyga, Sergei F; Heumann, Klaus G

    2006-01-01

    A method by inductively coupled plasma mass spectrometry (ICP-MS) was developed which allows the measurement of (236)U at concentration ranges down to 3 x 10(-14)g g(-1) and extremely low (236)U/(238)U isotope ratios in soil samples of 10(-7). By using the high-efficiency solution introduction system APEX in connection with a sector-field ICP-MS a sensitivity of more than 5,000 counts fg(-1) uranium was achieved. The use of an aerosol desolvating unit reduced the formation rate of uranium hydride ions UH(+)/U(+) down to a level of 10(-6). An abundance sensitivity of 3 x 10(-7) was observed for (236)U/(238)U isotope ratio measurements at mass resolution 4000. The detection limit for (236)U and the lowest detectable (236)U/(238)U isotope ratio were improved by more than two orders of magnitude compared with corresponding values by alpha spectrometry. Determination of uranium in soil samples collected in the vicinity of Chernobyl nuclear power plant (NPP) resulted in that the (236)U/(238)U isotope ratio is a much more sensitive and accurate marker for environmental contamination by spent uranium in comparison to the (235)U/(238)U isotope ratio. The ICP-MS technique allowed for the first time detection of irradiated uranium in soil samples even at distances more than 200 km to the north of Chernobyl NPP (Mogilev region). The concentration of (236)U in the upper 0-10 cm soil layers varied from 2 x 10(-9)g g(-1) within radioactive spots close to the Chernobyl NPP to 3 x 10(-13)g g(-1) on a sampling site located by >200 km from Chernobyl.

  19. 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)

    Michel, H.

    1999-01-01

    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

  20. 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)

    Fernandez Carretero, A.

    2002-01-01

    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)

  1. Sequential Injection Method for Rapid and Simultaneous Determination of 236U, 237Np, and Pu Isotopes in Seawater

    DEFF Research Database (Denmark)

    Qiao, Jixin; Hou, Xiaolin; Steier, Peter

    2013-01-01

    An automated analytical method implemented in a novel dual-column tandem sequential injection (SI) system was developed for simultaneous determination of 236U, 237Np, 239Pu, and 240Pu in seawater samples. A combination of TEVA and UTEVA extraction chromatography was exploited to separate and purify...... target analytes, whereupon plutonium and neptunium were simultaneously isolated and purified on TEVA, while uranium was collected on UTEVA. The separation behavior of U, Np, and Pu on TEVA–UTEVA columns was investigated in detail in order to achieve high chemical yields and complete purification...

  2. Mass dependence of azimuthal asymmetry in the fission of {sup 232}Th and {sup 233,235,236,238}U by polarized photons

    Energy Technology Data Exchange (ETDEWEB)

    Denyak, V.V. [National Science Center ' ' Kharkov Institute of Physics and Technology' ' , Kharkiv (Ukraine); Pele Pequeno Principe Research Institute, Curitiba (Brazil); Khvastunov, V.M. [National Science Center ' ' Kharkov Institute of Physics and Technology' ' , Kharkiv (Ukraine); Paschuk, S.A. [Federal University of Technology - Parana, Curitiba (Brazil); Schelin, H.R. [Federal University of Technology - Parana, Curitiba (Brazil); Pele Pequeno Principe Research Institute, Curitiba (Brazil)

    2013-04-15

    Fission of the even-even nuclei {sup 232}Th, {sup 236,238}U and even-odd nuclei {sup 233,235}U by linearly polarized photons has been studied at excitation energies in the region of a giant dipole resonance. The performed investigations unambiguously showed the existence of the fragment mass dependence of the cross section azimuthal asymmetry in the photofission of {sup 236}U and {sup 238}U. In addition, the obtained results provided the first evidence for the possible difference between the asymmetry values in asymmetric and symmetric mass distribution regions in the case of {sup 236}U. The measured cross section azimuthal asymmetry of the fission of {sup 232}Th does not show any fragment mass dependence. In the even-odd nuclei {sup 233}U and {sup 235}U the difference between the far-asymmetric and other mass distribution regions was also observed but with the statistical uncertainty not small enough for definitive conclusion. (orig.)

  3. Mass dependence of azimuthal asymmetry in the fission of 232Th and 233,235,236,238U by polarized photons

    International Nuclear Information System (INIS)

    Denyak, V.V.; Khvastunov, V.M.; Paschuk, S.A.; Schelin, H.R.

    2013-01-01

    Fission of the even-even nuclei 232 Th, 236,238 U and even-odd nuclei 233,235 U by linearly polarized photons has been studied at excitation energies in the region of a giant dipole resonance. The performed investigations unambiguously showed the existence of the fragment mass dependence of the cross section azimuthal asymmetry in the photofission of 236 U and 238 U. In addition, the obtained results provided the first evidence for the possible difference between the asymmetry values in asymmetric and symmetric mass distribution regions in the case of 236 U. The measured cross section azimuthal asymmetry of the fission of 232 Th does not show any fragment mass dependence. In the even-odd nuclei 233 U and 235 U the difference between the far-asymmetric and other mass distribution regions was also observed but with the statistical uncertainty not small enough for definitive conclusion. (orig.)

  4. Americium behaviour in plastic vessels

    International Nuclear Information System (INIS)

    Legarda, F.; Herranz, M.; Idoeta, R.; Abelairas, A.

    2010-01-01

    The adsorption of 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 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 241 Am is minimized with no water agitation, with PET or PVC plastics, and by water acidification.

  5. Phonon properties of americium phosphide

    Energy Technology Data Exchange (ETDEWEB)

    Arya, B. S., E-mail: bsarya13@yahoo.com [Department of Physics, Govt. Narmada P G College, Hoshangabad -461001 (India); Aynyas, Mahendra [Department of Physics, C. S. A. Govt. P. G. College Sehore-46601 (India); Sanyal, S. P. [Department of Physics, Barkatullah University, Bhopal-462026 (India)

    2016-05-23

    Phonon properties of AmP have been studied by using breathing shell models (BSM) which includes breathing motion of electrons of the Am atoms due to f-d hybridization. The phonon dispersion curves, specific heat calculated from present model. The calculated phonon dispersion curves of AmP are presented follow the same trend as observed in uranium phosphide. We discuss the significance of this approach in predicting the phonon dispersion curves of these compounds and examine the role of electron-phonon interaction.

  6. 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.

  7. Americium behaviour in plastic vessels.

    Science.gov (United States)

    Legarda, F; Herranz, M; Idoeta, R; Abelairas, A

    2010-01-01

    The adsorption of (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 (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 (241)Am is minimized with no water agitation, with PET or PVC plastics, and by water acidification. Copyright 2009 Elsevier Ltd. All rights reserved.

  8. 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)

  9. 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)

    Gosmain, Cecile-Aline

    2011-01-01

    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)

  10. Angular correlation between the heavy fragments and the light charged particles in tripartition of 236U and 252Cf

    International Nuclear Information System (INIS)

    Sowinski, M.

    1975-05-01

    The energy distributions and relative intensities of protons, deuterons, tritons and alpha-particles emitted along the fission axis during thermal neutron fission of 236 U are measured simultaneously with the energies of the two fission fragments. The mass distributions of the fragments, the total kinetic energy (TKE), the dependence of the mean TKE on the fragment mass, as well as the mean kinetic energy dependence of polar particles on the fragment mass and energy are deduced from these data. Although some experimental results agree remarkably well with the hypothesis that polar particles are evaporated in-flight from fission fragments, the general conclusion is that these particles are emitted according to some other mechanism

  11. Bio-aggregates based building materials state-of-the-art report of the RILEM Technical Committee 236-BBM

    CERN Document Server

    Collet, Florence

    2017-01-01

    The work of the RILEM Technical Committee (TC -236 BBM) was dedicated to the study of construction materials made from plant particles. It considered the question whether building materials containing as main raw material recyclable and easily available plant particles are renewable. This book includes a state-of-the-art report and an appendix. The state-of-the-art report relates to the description of vegetal aggregates. Then, hygrothermal properties, fire resistance, durability and finally the impact of the variability of the method of production of bio-based concrete are assessed. The appendix is a TC report which presents the experience of a working group. The goal was to define testing methods for the measurement of water absorption, bulk density, particle size distribution, and thermal conductivity of bio aggregates. The work is based on a first round robin test of the TC-BBM where the protocols in use by the different laboratories (labs) are compared. .

  12. Determination of depth of burnup of fuel in deposition in territory Belarus, after Chernobyl accident, with the help of a tracer of U-236

    International Nuclear Information System (INIS)

    Mironov, V.P.; Matusevich, Zh.L.; Kudryashov, V.P.; Ananich, P.I.; Zhuravkov, V.V.

    2002-01-01

    Experiments and calculations for determination of depth of burnup of fuel are carried out on separate sites in Belarus. As a tracer of Chernobyl deposition the uranium-236 was used. The average depth of burnup of fuel in 30 km zone is 9,4 MW*d/kgU

  13. Applicability of the fish embryo acute toxicity (FET) test (OECD 236) in the regulatory context of Registration, Evaluation, Authorisation, and Restriction of Chemicals (REACH).

    NARCIS (Netherlands)

    Sobanska, Marta; Scholz, Stefan; Nyman, Anna-Maija; Cesnaitis, Romanas; Gutierrez Alonso, Simon; Klüver, Nils; Kühne, Ralph; Tyle, Henrik; de Knecht, Joop; Dang, Zhichao; Lundbergh, Ivar; Carlon, Claudio; De Coen, Wim

    In 2013 the Organisation for Economic Co-operation and Development (OECD) test guideline (236) for fish embryo acute toxicity (FET) was adopted. It determines the acute toxicity of chemicals to embryonic fish. Previous studies show a good correlation of FET with the standard acute fish toxicity

  14. Complete Genome Sequence of Spiroplasma floricola 23-6T (ATCC 29989), a Bacterium Isolated from a Tulip Tree (Liriodendron tulipifera L.).

    Science.gov (United States)

    Tsai, Yi-Ming; Wu, Pei-Shan; Lo, Wen-Sui; Kuo, Chih-Horng

    2018-04-19

    Spiroplasma floricola 23-6 T (ATCC 29989) was isolated from the flower surface of a tulip tree ( Liriodendron tulipifera L.). Here, we report the complete genome sequence of this bacterium to facilitate the investigation of its biology and the comparative genomics among Spiroplasma species. Copyright © 2018 Tsai et al.

  15. Determination of irradiated reactor uranium in soil samples in Belarus using 236U as irradiated uranium tracer.

    Science.gov (United States)

    Mironov, Vladislav P; Matusevich, Janna L; Kudrjashov, Vladimir P; Boulyga, Sergei F; Becker, J Sabine

    2002-12-01

    This work presents experimental results on the distribution of irradiated reactor uranium from fallout after the accident at Chernobyl Nuclear Power Plant (NPP) in comparison to natural uranium distribution in different soil types. Oxidation processes and vertical migration of irradiated uranium in soils typical of the 30 km relocation area around Chernobyl NPP were studied using 236U as the tracer for irradiated reactor uranium and inductively coupled plasma mass spectrometry as the analytical method for uranium isotope ratio measurements. Measurements of natural uranium yielded significant variations of its concentration in upper soil layers from 2 x 10(-7) g g(-1) to 3.4 x 10(-6) g g(-1). Concentrations of irradiated uranium in the upper 0-10 cm soil layers at the investigated sampling sites varied from 5 x 10(-12) g g(-1) to 2 x 10(-6) g g(-1) depending on the distance from Chernobyl NPP. In the majority of investigated soil profiles 78% to 97% of irradiated "Chernobyl" uranium is still contained in the upper 0-10 cm soil layers. The physical and chemical characteristics of the soil do not have any significant influence on processes of fuel particle destruction. Results obtained using carbonate leaching of 236U confirmed that more than 60% of irradiated "Chernobyl" uranium is still in a tetravalent form, ie. it is included in the fuel matrix (non-oxidized fuel UO2). The average value of the destruction rate of fuel particles determined for the Western radioactive trace (k = 0.030 +/- 0.005 yr(-1)) and for the Northern radioactive trace (k = 0.035 + 0.009 yr(-1)) coincide within experimental errors. Use of leaching of fission products in comparison to leaching of uranium for study of the destruction rate of fuel particles yielded poor coincidence due to the fact that use of fission products does not take into account differences in the chemical properties of fission products and fuel matrix (uranium).

  16. Determination of 236U and transuranium elements in depleted uranium ammunition by α-spectrometry and ICP-MS

    International Nuclear Information System (INIS)

    Desideri, D.; Meli, M.A.; Roselli, C.; Testa, C.; Boulyga, S.F.; Becker, J.S.

    2002-01-01

    It is well known that ammunition containing depleted uranium (DU) was used by NATO during the Balkan conflict. To evaluate the origin of DU (the enrichment of natural uranium or the reprocessing of spent nuclear fuel) it is necessary to directly detect the presence of activation products ( 236 U, 239 Pu, 240 Pu, 241 Am, and 237 Np) in the ammunition. In this work the analysis of actinides by α-spectrometry was compared with that by inductively coupled plasma mass spectrometry (ICP-MS) after selective separation of ultratraces of transuranium elements from the uranium matrix. 242 Pu and 243 Am were added to calculate the chemical yield. Plutonium was separated from uranium by extraction chromatography, using tri-n-octylamine (TNOA), with a decontamination factor higher than 10 6 ; after elution plutonium was determined by ICP-MS ( 239 Pu and 240 Pu) and α-spectrometry ( 239+240 Pu) after electroplating. The concentration of Pu in two DU penetrator samples was 7 x 10 -12 g g -1 and 2 x 10 -11 g g -1 . The 240 Pu/ 239 Pu isotope ratio in one penetrator sample (0.12±0.04) was significantly lower than the 240 Pu/ 239 Pu ratios found in two soil samples from Kosovo (0.35±0.10 and 0.27±0.07). 241 Am was separated by extraction chromatography, using di(2-ethylhexyl)phosphoric acid (HDEHP), with a decontamination factor as high as 10 7 . The concentration of 241 Am in the penetrator samples was 2.7 x 10 -14 g g -1 and -15 g g -1 . In addition 237 Np was detected at ultratrace levels. In general, ICP-MS and α-spectrometry results were in good agreement.The presence of anthropogenic radionuclides ( 236 U, 239 Pu, 240 Pu, 241 Am, and 237 Np) in the penetrators indicates that at least part of the uranium originated from the reprocessing of nuclear fuel. Because the concentrations of radionuclides are very low, their radiotoxicological effect is negligible. (orig.)

  17. Determination of {sup 236}U and transuranium elements in depleted uranium ammunition by {alpha}-spectrometry and ICP-MS

    Energy Technology Data Exchange (ETDEWEB)

    Desideri, D.; Meli, M.A.; Roselli, C.; Testa, C. [General Chemistry Institute, Urbino University, Urbino (Italy); Boulyga, S.F.; Becker, J.S. [Central Department of Analytical Chemistry, Research Centre Juelich, Juelich (Germany)

    2002-11-01

    It is well known that ammunition containing depleted uranium (DU) was used by NATO during the Balkan conflict. To evaluate the origin of DU (the enrichment of natural uranium or the reprocessing of spent nuclear fuel) it is necessary to directly detect the presence of activation products ({sup 236}U, {sup 239}Pu, {sup 240}Pu, {sup 241}Am, and {sup 237}Np) in the ammunition. In this work the analysis of actinides by {alpha}-spectrometry was compared with that by inductively coupled plasma mass spectrometry (ICP-MS) after selective separation of ultratraces of transuranium elements from the uranium matrix. {sup 242}Pu and {sup 243}Am were added to calculate the chemical yield. Plutonium was separated from uranium by extraction chromatography, using tri-n-octylamine (TNOA), with a decontamination factor higher than 10{sup 6}; after elution plutonium was determined by ICP-MS ({sup 239}Pu and {sup 240}Pu) and {alpha}-spectrometry ({sup 239+240}Pu) after electroplating. The concentration of Pu in two DU penetrator samples was 7 x 10{sup -12} g g{sup -1} and 2 x 10{sup -11} g g{sup -1}. The {sup 240}Pu/{sup 239}Pu isotope ratio in one penetrator sample (0.12{+-}0.04) was significantly lower than the {sup 240}Pu/{sup 239}Pu ratios found in two soil samples from Kosovo (0.35{+-}0.10 and 0.27{+-}0.07). {sup 241}Am was separated by extraction chromatography, using di(2-ethylhexyl)phosphoric acid (HDEHP), with a decontamination factor as high as 10{sup 7}. The concentration of {sup 241}Am in the penetrator samples was 2.7 x 10{sup -14} g g{sup -1} and <9.4 x 10{sup -15} g g{sup -1}. In addition {sup 237}Np was detected at ultratrace levels. In general, ICP-MS and {alpha}-spectrometry results were in good agreement.The presence of anthropogenic radionuclides ({sup 236}U, {sup 239}Pu,{sup 240}Pu, {sup 241}Am, and {sup 237}Np) in the penetrators indicates that at least part of the uranium originated from the reprocessing of nuclear fuel. Because the concentrations of

  18. Determination of (236)U and transuranium elements in depleted uranium ammunition by alpha-spectrometry and ICP-MS.

    Science.gov (United States)

    Desideri, D; Meli, M A; Roselli, C; Testa, C; Boulyga, S F; Becker, J S

    2002-11-01

    It is well known that ammunition containing depleted uranium (DU) was used by NATO during the Balkan conflict. To evaluate the origin of DU (the enrichment of natural uranium or the reprocessing of spent nuclear fuel) it is necessary to directly detect the presence of activation products ((236)U, (239)Pu, (240)Pu, (241)Am, and (237)Np) in the ammunition. In this work the analysis of actinides by alpha-spectrometry was compared with that by inductively coupled plasma mass spectrometry (ICP-MS) after selective separation of ultratraces of transuranium elements from the uranium matrix. (242)Pu and (243)Am were added to calculate the chemical yield. Plutonium was separated from uranium by extraction chromatography, using tri- n-octylamine (TNOA), with a decontamination factor higher than 10(6); after elution plutonium was determined by ICP-MS ((239)Pu and (240)Pu) and alpha-spectrometry ((239+240)Pu) after electroplating. The concentration of Pu in two DU penetrator samples was 7 x 10(-12) g g(-1) and 2 x 10(-11) g g(-1). The (240)Pu/(239)Pu isotope ratio in one penetrator sample (0.12+/-0.04) was significantly lower than the (240)Pu/(239)Pu ratios found in two soil samples from Kosovo (0.35+/-0.10 and 0.27+/-0.07). (241)Am was separated by extraction chromatography, using di(2-ethylhexyl)phosphoric acid (HDEHP), with a decontamination factor as high as 10(7). The concentration of (241)Am in the penetrator samples was 2.7 x 10(-14) g g(-1) and <9.4 x 10(-15) g g(-1). In addition (237)Np was detected at ultratrace levels. In general, ICP-MS and alpha-spectrometry results were in good agreement. The presence of anthropogenic radionuclides ((236)U, (239)Pu,(240)Pu, (241)Am, and (237)Np) in the penetrators indicates that at least part of the uranium originated from the reprocessing of nuclear fuel. Because the concentrations of radionuclides are very low, their radiotoxicological effect is negligible.

  19. Numerical methods to analyze alpha spectra and application to the study of neptunium 237 and neptunium 236

    International Nuclear Information System (INIS)

    Garcia-Torano, E.

    1990-01-01

    A set of numerical methods to analize alpha spectra measured with semiconductor detectors are presented. The methods can be divided in two groups, the first being based in the X 2 minimization ands the second in the use of the Fourier Transform. The methods based in the minimization of X 2 can, in turn, be divided according to the model used to fit the spectra. Some of them use a monoenergetic line for the intercomparison with the other peaks in the same spectrum. The others take into account the analytical function developed to represent an alpha line. Both allow the determination of positions and areas of the components, as well as the uncertainties of the results. The Fast Fourier Transform is applied to the second group of methods, which include the smoothing of experimental data, and the deconvolution of spectra. Examples are given of the application of these methods to real spectra. The alpha spectra of 237 Np and 236 Np are studied by using some of the methods described in this work. (Author)

  20. Charge distribution of the 236U* fission fragments with accounting for angular momentum of the compound nuclei

    International Nuclear Information System (INIS)

    Volkov, N.G.; Emel'yanov, V.M.; Krajnov, V.P.

    1979-01-01

    In a statistical fission model calculated are charge distributions of fission fragments (CDFF) of a 236 U* nucleus and their dispersions as the functions of excitation energy and angular momentum (AM) of a compound nucleus as well as the effect of one-particle potential parameter on CDFF. The potential of two-center oscillator was choosen as the one-particle potential. The function of fissioning nucleus level density, which is necessary for calculations in the statistical approach, has been determined from one-particle spectrum. The scheme of calculations is realized with a computer. Presented are the results of calculating the dependence of a neutron gap size on nuclear temperature for various projections of total AM; CDFF for different values of E* excitation energy of AM projection and others. Calculated CDFF and experimental data were compared. Notwithstanding the availability of many parameters and a large volume of numerical calculations the model under consideration permits to describe many common regularities of heavy nucleus CDFF (experimental yields of charges, dispersion dependence on excitation energies and masses of nuclear fragments)